DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
This final action is in response to Applicant’s filing dated April 15, 2026. Claims 1-20 are currently pending and have been considered, as provided in more detail below. Claims 1, 11 and 20 have been amended.
*Examiner Note: Claim language is bolded. Cited References and Applicant’s arguments are italicized. Examiner interpretations are preceded with an asterisk *.
Response to Arguments
Applicant's arguments filed 4/15/26 have been fully considered but they are not persuasive. The Examiner respectfully does not agree with Applicant’s remarks on pages 16-17 of the response that states “there exists no teaching or disclosure within the entirety of English, Shue '252, Raza, and/or Shue '658 that teaches or suggests a flight control system that can alternatively operate in a vector rate mode in which inputs can be received from one or more inceptors, and apply flight control laws to map the inputs to command longitudinal and vertical movement of the tiltrotor aircraft, or a a reversionary mode in which the vector rate mode is not allowed to continue operating. Indeed, no prior art reference of record in the present case teaches or suggests any such feature”. Applicant’s argument is conclusory because it does not address the combined teaches of English, Shue 252, Shue 658 and Raza. These references collectively teach a tiltrotor FCC receiving multiple inceptor inputs, applying control laws to command longitudinal and vertical motion and using different control modes or fallback/reversion behavior in aircraft control systems which supports the maintained rejection of the amended claim.
As discussed in detail below, English teaches am ode-based tiltrotor flight control system in which different flight regimes use different effectors and control allocations across hover, transition and airplane modes. Shue 252 is being replied upon to teach inceptor-management and state flow logic that selectively passes or stops command inputs based on the applicable mode which is evidence that command inputs may b e enabled, disabled or rerouted under mode logic. Shue 658 discloses a multi-loop flight control architecture in which control law behavior varies by operating mode and design requirements to support the use of alternate control laws when a primary law is not used. Raza teaches an aircraft control system that maps pilot inputs to higher level speed and climb/descent type commands under selectable control modes. In this connection, it would have been obvious to implement English with a vector rate mode and a reversionary mode that disables that vector rate mode and reverts to an alternate control law.
Applicant’s argument is not persuasive because the cited references, when considered in combination, clearly teach or render obvious a tiltrotor flight control system having a flight control computer that receiver multiple inceptor inputs and applies control laws to map those inputs to commanded translation and vertical motion. Shue 252 teaches management of multiple inceptors and reassignment or limitation of inceptor authority base don mode or system state. Shue 658 teaches a hierarchical flight control system in which pilot inputs are processed through control lops to command aircraft motion and Raza teaches flight control logic that maps pilot inputs to speed and vertical trajectory commands. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to implement the claimed “vector rate mode” as a known outer-loop control mode and to provide a reversionary mode that stops that mode in favor of an alternate control law since this mode switching is a routine design choice in aircraft flight control systems. Accordingly, Applicant’s amendments and arguments are not persuasive and the rejection is maintained as discussed in detail below.
Response to Amendment
Regarding the rejection under 35 USC 103, the amendments made to the claims fail to overcome the prior art. The rejection under 35 USC 103 is maintained as outlined below.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over English (US 2020/0333805A1) in view of Shue’252 (US 2019/0241252A1) in view of Raza (WO 2024/092202A1) and further in view of Shue’658 (US 2008/0097658A1).
Regarding claim 1, as amended, English discloses A flight control system (see at least para.
[0039] of English which discloses “The system 100 and method 200 can be used in relation to various flight regimes of the transition aircraft (e.g., tilt-prop aircraft, tiltrotor aircraft, tilt thrust aircraft, etc.)”) for a tiltrotor aircraft (see at least para. [0037] of English which discloses “a tiltrotor (or tilt-prop) aircraft”), comprising:
a plurality of propulsion systems (Fig. 13A-13C, 118 and see at least para. [0037] of English which discloses “a plurality of aircraft propulsion systems 118”) each independently tiltable (see at least para. [0109] of English which discloses “propulsion units 118 (e.g., tiltable propellers with variable blade pitch, an example is shown in FIGS. 13A-C), and any other suitable control surfaces and/or actuatable mechanisms that can affect the flight of the aircraft”) between a vertical position and a horizontal position (see at least para. [0020] of English which discloses “FIGS. 13A-C is a side view of an example of a tilt rotor mechanism in the forward, transition, and hover regimes, respectively”, *Fig. 13A illustrates propulsion system 118 in a vertical orientation and Fig. 13C illustrates propulsion system 118 in a horizontal orientation) by aircraft effectors (see at least para. [0039] of English which discloses “a set of aircraft effectors that aerodynamically control the forces and moments on the aircraft”, *This may include propulsion units and other actuatable mechanisms); and
a flight control computer (see at least para. [0026] of English which discloses “the unified command system 100 includes an input mechanism 101, a flight processor 102 that receives command input 104 from the input mechanism and translates the input into control output 105, and effectors 110 that are actuated according to the control output … the unified command system 100 can additionally or alternatively include any other suitable components”, which collectively form a flight control computer and English discloses a flight control computer in the form of a flight processor included within a unified command system (see at least para. [0026], which discloses that the unified command system includes a flight processor that receives command input form an input mechanism and translate the input into control output for actuating effectors). Such a flight processor is a functional equivalent of a flight control computer. Also note that para. [0113] of English describes “a machine configured to receive a computer-readable medium storing computer-readable instructions”, *Examiner interprets this machine to be a flight control computer) configured to control the tiltrotor aircraft effectors (see at least para. [0049] of English which discloses “the unified command system 100 includes an input mechanism, one or more sensors, a flight processor that translates the input into control output, and effectors that are actuated according to the control output”) in response to inputs from inceptors (see at least para. [0051] of English which discloses “the inceptor can be the only manual control input in the cockpit or aircraft. However, other control inputs (e.g., pedals, buttons, secondary inceptors, etc.) can optionally be included in the aircraft”, *An inceptor provides manual control input and see para. [0026] which discloses that the flight processor translates command input into control output for effectors), the flight control computer comprising one or more processors (see at least para. [0049] of English which discloses “the unified command system 100 includes an input mechanism, one or more sensors, a flight processor that translates the input into control output, and effectors that are actuated according to the control output”) and a memory (see at least para. [0113] of English which discloses “memory, EEPROMs, optical devices (CD or DVD), hard drives, floppy drives, or any suitable device. The computer-executable component is preferably a general or application specific processor, but any suitable dedicated hardware or hardware/firmware combination device can alternatively or additionally execute the instructions”, *This discloses memory and computer-executable instructions executed by a processor), wherein the memory stores instructions (see at least para. [0113] of English which discloses “storing computer-readable instructions. The instructions are preferably executed by computer-executable components preferably integrated with and/or part of the system. The computer-readable medium can be stored on any suitable computer-readable media such as RAMs, ROMs, flash memory, EEPROMs, optical devices (CD or DVD), hard drives, floppy drives, or any suitable device”) for controlling aircraft effectors, the instructions causing the flight control computer to perform (see at least para. [0039] of English which discloses “The flight regimes are each associated with a set of aircraft effectors that aerodynamically control the forces and moments on the aircraft, and the set of aircraft effectors can vary among the various flight regimes”) the steps of:
receive inputs (see at least para. [0071] of English which discloses “The flight processor can also function to receive input from a vehicle navigation system 150 (e.g., vehicle state 108, flight regime 107, effector state, existing forces and/or moments on the aircraft”) from a first inceptor (see at least para. [0061] of English which discloses “wherein a first inceptor is operable in a first flight regime (e.g., hover)”) and a second inceptor (see at least para. [0061] of English which discloses “the second inceptor is operable in a second flight regime (e.g., airplane), and both inceptors are operable (e.g., in a redundant manner, in a non-redundant manner, etc.) in a transition flight regime” and see at least para. [0051] of English which discloses “the inceptor can be the only manual control input in the cockpit or aircraft. However, other control inputs (e.g., pedals, buttons, secondary inceptors, etc.) can optionally be included in the aircraft”, *English further discloses that the flight control system is configured to receive inputs (see at least para. [0071]) and includes multiple inceptors, including a first inceptor operable in a first flight regime and a second inceptor operable in a second flight regime, with both inceptors operable during a transition flight regime (see at least para. [0061). In this connection, English further discloses that additional or secondary inceptors may be provided as taught in at least para. [0051]); and
to map the inputs to command longitudinal and vertical movement (see at least para. [0099] of English which discloses “Alternative variations of the unified command model can include a two-inceptor mapping of longitudinal, lateral, and vertical control. In such variations, each inceptor axis defines a longitudinal (e.g., X-axis) and lateral (e.g., Y-axis) mapping and the model includes a blend region (e.g., transition regime) between forward flight (e.g., airplane) and hover regimes. With respect to the longitudinal mapping, the first inceptor (e.g., “pitch inceptor”) can control the aircraft pitch (e.g., vertical component of the flightpath) when the aircraft is in forward flight, and the vertical motion rate when the aircraft is in hover”) of the tiltrotor aircraft (see at least para. [0043] of English which discloses “The tiltrotor aircraft defines various geometrical features. The tiltrotor aircraft defines principal geometric axes, as shown in FIGS. 17A-17B, including: a vertical axis 132 (e.g., yaw axis), a longitudinal 134 axis (e.g., a roll axis), and a lateral axis 136 (e.g., a pitch axis). The vertical, longitudinal, and lateral axes can be defined such that they intersect at the CoG of the aircraft, and a pure moment about any one of the aforementioned axes causes the aircraft to rotate about the vertical, longitudinal, and lateral axes, respectively”),
wherein the first inceptor inputs command longitudinal speed (see at least para. [0096] of English which discloses “in the single-inceptor command model, longitudinal (e.g., X-axis) groundspeed can be commanded via the A-axis inceptor motion”) and acceleration of the tiltrotor aircraft (see at least para. [0096] of English which discloses “The A-axis actuation can be dynamically mapped between aircraft velocity and acceleration (e.g., wherein the A-axis commands velocity control when the aircraft is moving at near-zero velocity, and commands acceleration control”) in a hover flight mode (see at least para. [0061] of English which discloses “a first inceptor is operable in a first flight regime (e.g., hover)”, *English teaches that in hover flight mode, an inceptor commands longitudinal groundspeed and that the same inceptor dynamically commands longitudinal speed and acceleration, via a command model – see para. [0096] of English. In this connection, English clearly teaches that pilot inceptor inputs are mapped by a flight processor to “translational motion … in the longitudinal direction when the aircraft is in hover”- see para. [0099] of English. See at least para. [0096] of English which discloses “longitudinal (e.g., X-axis) groundspeed can be commanded via the A-axis inceptor motion (e.g., a single axis actuator on the inceptor, such as a wheel as shown in FIG. 6). The A-axis actuation can be dynamically mapped between aircraft velocity and acceleration”, * this expressly teaches that, in hover flight, longitudinal groundspeed id commanded via an inceptor axis, and that the same inceptor axis is dynamically mapped between velocity and acceleration. English further teaches that, in forward flight, the same inceptor axis blends to airspeed acceleration control. See at least para. [0097] of English which discloses “the A-axis inceptor motion blends between commanding groundspeed (e.g., in hover) and airspeed acceleration control (e.g., in forward flight)”. Finally see at least para. [0124] of English which discloses “inceptor motion is translated into X-translational rate control (e.g., in the hover regime) and X-acceleration and airspeed (or speed) maintenance control (e.g., in the forward flight regime”, *English teaches that a first inceptor commands longitudinal speed and acceleration, including acceleration command in forward flight).
Regarding the newly added limitation of “to operate in a vector rate mode”, English does
disclose flightpath vectoring in hover and forward flight describes the task environment and coupling between attitude and flightpath (see at least para. [0039] of English which discloses “The flight regimes are each associated with a set of aircraft effectors that aerodynamically control the forces and moments on the aircraft, and the set of aircraft effectors can vary among the various flight regimes. For example, forward flight as an airplane can be largely a flightpath vectoring task wherein airplane attitude is largely coupled to the flightpath, as compared to hover which can be largely a horizontal positioning task with a vertical control component, wherein the aircraft attitude is substantially less coupled to the flightpath vector. The system and method function to automatically determine the set of effectors and effector states associated with a commanded aircraft maneuver or action demanded by the user (e.g., such that the user does not need to devote cognitive energy to identifying and commanding the set of effectors directly). As shown in FIG. 3, these flight regimes can include: vertical takeoff and landing (VTOL) or hover, wherein the aircraft yaw is controlled through nacelle tilt, and aircraft roll, pitch, and attitude are controlled through propeller pitch and motor RPM; conventional takeoff and landing (CTOL) and airplane, wherein traditional flight control surfaces are used to control the aircraft yaw, roll, pitch, and attitude (e.g., flaps, ruddervators, ailerons, propeller thrust, etc.); and transition (e.g., between forward flight as an airplane and hover or vice versa), wherein the thrust (e.g., blade pitch and motor RPM), propeller unit tilt angle, and control surfaces are used in a dynamically adjusted manner during conversion between airplane and hover flight”).
English may not explicitly disclose the newly added limitation of to operate in a vector rate
mode.
However, Shue 252 teaches a multi-loop flight control architecture in which the pilot
inceptor inputs are processed through control laws to generate commanded longitudinal and vertical motion, including commanded velocity and acceleration along relevant axes (see at least para. [0081] of Shue 252 which discloses “For pilot command inputs in auto-pilot, mission, and navigation modes, the individual control laws loop design may be designed differently depending on the design requirements, such as coupled or uncoupled mode. For example, in autopilot mode, the pilot commands can be designed as coupled or uncoupled function with hold situation. Therefore, the delta stick on individual axis and airspeed regions will act differently. The pilot commands will just follow the mode switch logic to accomplish the pilot command input motions. Similarly, the commands from ground control station joysticks and aircraft inceptors will work like the delta stick functions following the control laws logic state to fly the aircraft”, *Examiner interprets this as corresponding to the claimed operation in a vector rate mode).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the system of English to operate in a vector rate mode, as taught in Shue’252 with a reasonable expectation of success in order to reduce pilot workload and provide a more intuitive and unified command concept across hover, transition and airplane flight phases by mapping inceptor inputs to translational rate commands instead of requiring the pilot to directly manage effector by effector control.
Regarding the newly added limitation of operation in a vector rate mode, Raza teaches
an aircraft control system that maps pilot inputs to high-level speed and climb/descent-type commands under selectable control modes which confirms that the use of inceptor inputs to command translational and vertical movement is a known and predictable control-law implementation (see at least para. [0044] of Raza which discloses “an operator may utilize longitudinal inputs 308 of left-hand inceptor 302 to provide an overall vertical adjustment (e.g., adjustment in altitude) to aircraft 10. Due to inceptor 302 being at angle “A”, part of the movement of inceptor 302 matches the requested vertical movement of the aircraft (e.g., a forward and downward movement of inceptor 302 causes descent of aircraft 10). In some examples, most of the motion of inceptor 302 may match the vertical motion of the aircraft (e.g., examples where angle “A” is greater than 45 degrees). In other examples, less than half of the movement of inceptor 302 may match the corresponding vertical motion”).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to configure the tiltrotor flight control computer of English to operate in a vector rate mode in which first and second inceptors command longitudinal speed/acceleration and climb/descent rate in both hover and cruise mode because this type of rate-command outer loop control is a conventional and predictable use of known aircraft control laws to simplify pilot workload and mange flight across modes. The cited prior art already teaches flight control computers using control laws to command rate-based translational motion, so adding the operation in the vector rate mode does not add patentable distinction.
English discloses a flight control system for a tiltrotor/VTOL aircraft in which a flight
processor applies control logic to map inceptor inputs to commanded aircraft motion, including longitudinal and vertical movement, and to generate corresponding control outputs to aircraft effectors ( see at least paras. [0026], [0049], [0061] and [0071] of English). English further teaches that pilot command inputs are translated by the flight processor into motion commands across hover, transition, and forward flight regimes.
English may not explicitly label the logic as flight control laws to map the inputs to
command longitudinal and vertical movement of the tiltrotor aircraft.
However, in the same field of endeavor, Shue teaches apply flight control laws (see at least
para. [0044] of Shue’252 which discloses “the flight control laws logic mode requirements in FCC”, *Shue teaches the flight control computer (see at least para. [0029] of Shue which discloses “flight control computer to allow the aircraft to be operated” and para. [0045] of Shue which discloses “The device can be a separated unit or the related software, which can be integrated/installed with the flight control computer or aircraft mission computer depending on aircraft vehicle management system”) implementing flight control laws including logic mode requirements, for processing inceptor inputs and generating aircraft control commands. Also, see at least para. [0055] of Shue’252 which discloses “the tiltrotor controls are with combination of helicopter controls and airplane control surfaces. A tiltrotor also contains nacelles tilted up and down functions, which can be controlled by the longitudinal stick with auto nacelle tilt followed by tiltrotor corridor design. The tiltrotor nacelle tilted up and down functions can also be controlled by the pilot”, *Shue teaches tiltrotor specific control logic for handling inputs during different nacelle angle flight conditions, including combinations of helicopter type and airplane type control strategies. Therefore, Shue explicitly supports the use of flight control laws executed by a flight control computer to map inputs to aircraft control outputs in a tiltrotor context).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the system of English to include logic as flight control laws to map the inputs to command longitudinal and vertical movement of the tiltrotor aircraft, as taught in Shue’252 with a reasonable expectation of success in order to implement the command mapping in a concrete flight control manner for improved flight control. See para. [0055] of Shue for motivation.
English does teach certain flight modes (see at least para. [0061] of English which discloses
“two inceptors (e.g., wherein helicopter-analogous actions are associated with a right-hand inceptor, wherein airplane-analogous actions are associated with a left-hand inceptor, vice versa, etc.). In another example, the system can include two inceptors, wherein a first inceptor is operable in a first flight regime (e.g., hover) and the second inceptor is operable in a second flight regime (e.g., airplane), and both inceptors are operable (e.g., in a redundant manner, in a non-redundant manner, etc.) in a transition flight regime”, * This is evidence of operation across hover, transition and forward flight regimes).
English, as modified by Shue‘252, may not explicitly disclose in a cruise flight mode and that
the same inceptor command semantics are preserved in both hover and cruise modes), and climb and descent rates in both hover and cruise flight modes.
However, in the same field of endeavor, Raza discloses both a cruise flight mode (see at
least para. [0022] of Raza which discloses “a cruise stage”) and a hover flight mode (see at least para. [0049] of Raza which discloses “whether the aircraft is experiencing rotor-borne flight, wing-borne flight, or a transition between rotor-borne and wing-borne flight”, *The rotor-borne flight is equivalent to hover flight mode and the wing-borne flight is equivalent to cruise flight mode), and the second inceptor inputs command climb and descent in both hover and cruise flight modes (see at least para. [0044] of Raza which discloses “longitudinal inputs 308 of left-hand inceptor 302 to provide an overall vertical adjustment (e.g., adjustment in altitude) to aircraft 10. Due to inceptor 302 being at angle “A”, part of the movement of inceptor 302 matches the requested vertical movement of the aircraft (e.g., a forward and downward movement of inceptor 302 causes descent of aircraft 10). In some examples, most of the motion of inceptor 302 may match the vertical motion of the aircraft (e.g., examples where angle “A” is greater than 45 degrees). In other examples, less than half of the movement of inceptor 302 may match the corresponding vertical motion”, * Raza teaches the inceptor motion corresponds to upward and downward aircraft movement, i.e., climb and descent).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the flight control system of English, as modified by Shue’252, to include commands across hover and cruise flight modes, as taught by Raza with a reasonable expectation of success in order to facilitate the application of known flight control objectives (speed/acceleration and vertical rate commands) using known processor based control laws in a predictable manner to achieve intuitive pilot control across different flight plans. See para. [0044] and [0049] of Raza for motivation.
While Raza teaches commanding upward and downward aircraft movement via inceptor
inputs across rotor-borne and wing-borne flight, Raza may not explicitly teach commanding rates of climb and descent.
However, Shue’658 discloses inputs command climb and descent rates (see at least para.
[0099] of Shue’658 which discloses “the difference between a reference and vertical velocity for climb and descent commands. The reference is preferably supplied by a selector knob (or wheel) located on the FGS control panel or through a “beep” switch located on a control stick grip (preferably the power lever) that slews a reference integrator within the FGS. Rate and magnitude limits are designed on the reference consistent with the maneuver limits desired”, *This constitutes express teaching of vertical velocity as a commanded variable used for climb and descent commands, thereby supplying the claimed rate-command limitation).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the flight control system of English, as modified by Shue’252, and Raza to include commanding rates of climb and descent as taught in Shue’658 with a reasonable expectation of success in order to improve inceptor ability to command climb/descent rates, thereby completing the claimed control law mapping for vertical movement. See para. [0099] of shue’658 for motivation.
As discussed above, English teaches a mode-based tiltrotor control system in which different
flight regimes use different effectors and control allocations.
English may not explicitly disclose the newly added limitation of “alternatively operate in a
reversionary mode in which the vector rate mode is not allowed to continue operating”.
However, Shue 252 discloses inceptor-management and state-flow logic that selectively
passes or stops command inputs based on the applicable mode (see at least para. [0103] of Shue 252 which discloses “the total wireless commands can be finite sets as N. The action is to form an enable switching function to allow the individual command to be ON (pass through) or OFF (stop). Note that only one priority command set will be passed through and controlled by the state flow logic switching algorithm design”). Shue 658 teaches a multi-loop flight control architecture in which control-law behavior varies according to operating mode and design requirements (see at least para. [0024] of Shue 658 which discloses “The three control loop design of the present invention will robustly enlarge the stability of the aircraft control laws. Instead of using classic feedback control law, the present invention enhances the system by: (1) leaving the strongest portion of classic feedback control system; and (2) introducing two other control laws to handle the natural weakness of classic feedback control law. The present invention saves flight test periods and shortens the time required to design control laws. Use of the three control loops has been as capable of making unstable aircraft to be not only stabilized but also guided and navigated, whereas the pure classic feedback control laws cannot even stabilize the system”, *Examiner interprets this disclosure of a multi-loop flight control architecture in which aircraft control may be implemented through different outer-loop control laws, and the broader flight-control art recognizes switching between rate command and alternate control law modes based on operating conditions which is equivalent to operating in a reversionary mode that doesn’t allow the vector rate mode).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the system of English to alternatively operate in a reversionary mode in which the vector rate mode is not allowed to continue operating and possibly reverts to an alternate control law when required for safe, predictable flight, as taught in Shue 252 and Shue 658 with a reasonable expectation of success since switching between command laws and reconfiguring control authority based on operating conditions is a known and predictable design choice in aircraft control systems.
Regarding claim 2, English, as modified by Shue’252, Raza and Shue’658 discloses wherein
the instructions further causing the flight control computer to perform the steps of: converting a signal representing a longitudinal force applied to the first inceptor (see at least para. [0026] of English which discloses “a flight processor 102 that receives command input 104 from the input mechanism and translates the input into control output 105, and effectors 110 that are actuated according to the control output. The system can optionally include: one or more sensors, a vehicle navigation system which determines a vehicle state and/or flight regime based on data from the one or more sensors 120, and a vehicle guidance system” and para. [0116] of English discloses “sing an input mechanism (e.g., an inceptor, a pair of inceptors, etc.) substantially as described above in relation to the system 100 but can additionally or alternatively be performed using any suitable means of obtaining input”, *English teaches the flight processor is the component that performs the conversion and the conversion is from inceptor input to commanded aircraft motion) into an altitude rate change (see at least para. [0095] of English which discloses “altitude) data is available, the vertical rate command can schedule a height-change rate of the aircraft”) in hover flight mode or into a flight path angle change (see at least para. [0027] of English which discloses “a user 140 (e.g., pilot, non-pilot) to control output variables of aircraft operation (e.g., aircraft actions, speed, airspeed, groundspeed, flight path, etc.) “) in cruise flight mode; converting a signal representing a longitudinal force applied to the second inceptor into a longitudinal velocity (see at least para. [0096] of English which discloses “velocity and acceleration (e.g., wherein the A-axis commands velocity control when the aircraft is moving at near-zero velocity, and commands acceleration control when further away from the zero-velocity point”) in hover flight mode or into a longitudinal acceleration in cruise flight mode; converting a signal representing a lateral force applied to the second inceptor into a lateral velocity in hover flight mode or into a roll rate in cruise flight mode; and converting a signal representing a twist force applied to the second inceptor into a yaw rate command in hover flight mode or into a sideslip command in cruise flight mode (see at least para. [0097] of English which discloses “ the motion of the inceptor along the 4 independent axes blends between controlling different aspects of the aircraft attitude and motion. In a specific example, longitudinal inceptor motion (e.g., along the X-axis) blends between commanding vertical rate (e.g., in hover) and commanding flightpath rate (e.g., in forward flight)”, *English teaches converting force based inceptor inputs into different commanded aircraft motion variables depending on flight regimes, including converting longitudinal, lateral, and twist forces into a vertical rate (hover), etc. and see para. [0096]-[0097]).
Regarding claim 3, English, as modified by Shue’252, Raza and Shue’658 discloses wherein
the instructions further causing the flight control computer to perform the steps of: converting a signal representing a longitudinal force applied to the first inceptor into a thrust offset command, wherein forward-directed forces correspond to a thrust decrease and backward-directed forces correspond to a thrust increase (see at least para. [0130] of English which discloses “thrust availability, envelope limits, structural limits, terrain limits, etc.), according to demand prioritization. This can include preferentially controlling effectors based on a predetermined demand prioritization, even in cases wherein the user demands (e.g., provides input) actions that require deprioritized effector control. For example, in the hover regime, attitude control can be prioritized over velocities (e.g., thrust) or accelerations; in the transition regime, vertical thrust components can be prioritized over horizontal components”); converting signals from a switch on the first inceptor into a thrust bias setting; converting a signal representing a longitudinal force applied to the second inceptor into a pitch attitude command; converting a signal representing a lateral force applied to the second inceptor into a roll attitude command (see at least para. [0099] of English which discloses “the first inceptor (e.g., “roll inceptor”) can command coordinated turns (e.g., banking turns) when the aircraft is in forward flight, and yaw (e.g., heading) control when the aircraft is in hover. The second inceptor (e.g., “yaw inceptor”) can map commands to sideslip (e.g., de-coordinated heading adjustment) when the aircraft is in forward flight, and to lateral (e.g., left/right) translational control in hover”); converting a signal representing a twist force applied to the second inceptor into a yaw rate command (see at least para. [0100] of English which discloses “yaw response in the hover regime, and a blended sideslip and yaw response in the transition regime. The third input axis also optionally maps to steering during ground operations (taxiing). Preferably, the yaw response is a heading rate (yaw rate) response”); and converting signals from a switch on the second inceptor into a conversion command (see at least para. [0116] of English which discloses “convert the user's intention into an input that can be processed (e.g., by a flight processor) into control outputs (e.g., for actuating aircraft effectors). Block S210 is preferably performed using an input mechanism (e.g., an inceptor, a pair of inceptors, etc.) substantially as described above in relation to the system 100 but can additionally or alternatively be performed using any suitable means of obtaining input (e.g., audio commands”).
Regarding claim 4, English, as modified by Shue’252, Raza and Shue’658 discloses wherein
the instructions further causing the flight control computer to perform the steps of: converting a signal representing a longitudinal force applied to the first inceptor into an altitude rate change (see at least para. [0095] of English which discloses “altitude) data is available, the vertical rate command can schedule a height-change rate of the aircraft”) in hover flight mode or into a flight path angle change (see at least para. [0027] of English which discloses “a user 140 (e.g., pilot, non-pilot) to control output variables of aircraft operation (e.g., aircraft actions, speed, airspeed, groundspeed, flight path, etc.) “) in cruise flight mode; converting a signal representing a longitudinal force applied to the second inceptor into a longitudinal velocity (see at least para. [0096] of English which discloses “velocity and acceleration (e.g., wherein the A-axis commands velocity control when the aircraft is moving at near-zero velocity, and commands acceleration control when further away from the zero-velocity point”) in hover flight mode or into a longitudinal acceleration in cruise flight mode; converting a signal representing a lateral force applied to the second inceptor into a lateral velocity in hover flight mode or into a roll rate in cruise flight mode; and converting signals representing forces applied to floor pedals into a yaw rate command in hover flight mode or into a sideslip command in cruise flight mode (see at least para. [0097] of English which discloses “ the motion of the inceptor along the 4 independent axes blends between controlling different aspects of the aircraft attitude and motion. In a specific example, longitudinal inceptor motion (e.g., along the X-axis) blends between commanding vertical rate (e.g., in hover) and commanding flightpath rate (e.g., in forward flight)”, *English teaches converting force based inceptor inputs into different commanded aircraft motion variables depending on flight regimes, including converting longitudinal, lateral, and twist forces into a vertical rate (hover), etc. and see para. [0096]-[0097]).
Regarding claim 5, English, as modified by Shue’252, Raza and Shue’658 discloses wherein
the instructions further causing the flight control computer to perform the steps of: converting a signal representing a longitudinal force applied to the first inceptor into a longitudinal velocity in hover flight mode or into a longitudinal acceleration in cruise flight mode; converting a signal representing a longitudinal force applied to the second inceptor into; an altitude rate change (see at least para. [0095] of English which discloses “altitude) data is available, the vertical rate command can schedule a height-change rate of the aircraft”) in hover flight mode or into a flight path angle change (see at least para. [0027] of English which discloses “a user 140 (e.g., pilot, non-pilot) to control output variables of aircraft operation (e.g., aircraft actions, speed, airspeed, groundspeed, flight path, etc.) “) in cruise flight mode; converting a signal representing a lateral force applied to the second inceptor into a lateral velocity in hover flight mode or into a roll rate in cruise flight mode; and converting a signal representing a twist force applied to the second inceptor into a yaw rate command (see at least para. [0100] of English which discloses “yaw response in the hover regime, and a blended sideslip and yaw response in the transition regime. The third input axis also optionally maps to steering during ground operations (taxiing). Preferably, the yaw response is a heading rate (yaw rate) response”) in hover flight mode or into a sideslip command in cruise flight mode (see at least para. [0094] of English which discloses “the single-inceptor commands sideslip. Z-twist inceptor input can command aircraft sideslip by pointing the nose of the aircraft in the direction of the inceptor twist. Such sideslip commands can change the heading of the aircraft without changing the flightpath direction, because the flight processor automatically compensates for the sideslip by actuating a combination of effectors to induce the countervailing bank needed to prevent a bank turn. In a specific variant, the Z-twist inceptor input can command sideslip below a threshold airspeed. Above the threshold airspeed, Z-twist inceptor input can be ignored or otherwise suitably used to generate control output”).
Regarding claim 6, English, as modified by Shue’252, Raza and Shue’658 discloses wherein
the instructions further causing the flight control computer to perform the steps of: converting a signal representing a longitudinal force applied to the first inceptor into a longitudinal velocity in hover flight mode or into a longitudinal acceleration in cruise flight mode; converting a signal representing a longitudinal force applied to the second inceptor into; an altitude rate change (see at least para. [0095] of English which discloses “altitude) data is available, the vertical rate command can schedule a height-change rate of the aircraft”) in hover flight mode or into a flight path angle change (see at least para. [0027] of English which discloses “a user 140 (e.g., pilot, non-pilot) to control output variables of aircraft operation (e.g., aircraft actions, speed, airspeed, groundspeed, flight path, etc.) “) in cruise flight mode; converting a signal representing a lateral force applied to the second inceptor into a lateral velocity in hover flight mode or into a roll rate in cruise flight mode; and converting signals representing forces applied to floor pedals into a yaw rate command in hover flight mode or into a sideslip command in cruise flight mode (see at least para. [0094] of English which discloses “the single-inceptor commands sideslip. Z-twist inceptor input can command aircraft sideslip by pointing the nose of the aircraft in the direction of the inceptor twist. Such sideslip commands can change the heading of the aircraft without changing the flightpath direction, because the flight processor automatically compensates for the sideslip by actuating a combination of effectors to induce the countervailing bank needed to prevent a bank turn. In a specific variant, the Z-twist inceptor input can command sideslip below a threshold airspeed. Above the threshold airspeed, Z-twist inceptor input can be ignored or otherwise suitably used to generate control output”).
Regarding claim 7, English, as modified by Shue’252, Raza and Shue’658 discloses wherein
the instructions further causing the flight control computer to perform the steps of: converting a signal representing a longitudinal force applied to the first inceptor into a thrust offset command, wherein forward-directed forces correspond to a thrust increase and backward-directed forces correspond to a thrust decrease; converting signals from a switch on the first inceptor into a thrust bias setting; converting a signal representing a longitudinal force applied to the second inceptor into a pitch attitude command; converting a signal representing a lateral force applied to the second inceptor into a roll attitude command; converting a signal representing a twist force applied to the second inceptor into a yaw rate command (see at least para. [0100] of English which discloses “yaw response in the hover regime, and a blended sideslip and yaw response in the transition regime. The third input axis also optionally maps to steering during ground operations (taxiing). Preferably, the yaw response is a heading rate (yaw rate) response”); and converting signals from a switch on the second inceptor into a conversion command (see at least para. [0116] of English which discloses “convert the user's intention into an input that can be processed (e.g., by a flight processor) into control outputs (e.g., for actuating aircraft effectors). Block S210 is preferably performed using an input mechanism (e.g., an inceptor, a pair of inceptors, etc.) substantially as described above in relation to the system 100 but can additionally or alternatively be performed using any suitable means of obtaining input (e.g., audio commands”).
Regarding claim 8, English, as modified by Shue’252, Raza and Shue’658 discloses wherein
the instructions further causing the flight control computer to: transition from longitudinal velocity and lateral velocity changes in hover flight mode to longitudinal acceleration changes and roll rate changes in cruise flight mode at a discrete airspeed (see at least para. [0097] of English which discloses “airspeed acceleration control (e.g., in forward flight); and the pitch attitude of the aircraft can be gradually de-coupled from the flightpath control as the aircraft slows from forward flight into hover”, *English explicitly describes transitions bounded by airspeed and flight condition thresholds).
Regarding claim 9, English, as modified by Shue’252, Raza and Shue’658 discloses wherein
the instructions further causing the flight control computer to :transition from altitude rate changes and yaw rate changes in hover flight mode to flight path angle changes and sideslip changes in cruise flight mode at a first airspeed when the tiltrotor aircraft is accelerating, and transition from flight path angle changes and sideslip changes in cruise flight mode to altitude rate changes and yaw rate changes in hover flight mode at a second airspeed when the tiltrotor aircraft is decelerating, wherein the second airspeed is lower than the first airspeed (see at least para. [0097] of English which discloses “airspeed acceleration control (e.g., in forward flight); and the pitch attitude of the aircraft can be gradually de-coupled from the flightpath control as the aircraft slows from forward flight into hover. The blending of each of the aforementioned command axes is preferably scheduled against the airspeed of the aircraft (e.g., wherein commands are mapped entirely to hover behavior at an airspeed substantially equal to zero and mapped entirely to airplane behavior at an airspeed greater than the minimum stall speed, and mapped to transitional control outputs by the flight processor in proportion to the airspeed between zero and the minimum stall speed)”).
Regarding claim 10, English, as modified by Shue’252, Raza and Shue’658 discloses wherein
the plurality of propulsion systems (Fig. 13A-13C, 118 and see at least para. [0037] of English which discloses “a plurality of aircraft propulsion systems 118”) have a generally vertical orientation in the hover mode and a generally horizontal orientation in the cruise mode, and wherein additional propulsion systems are fixed in a horizontal position (see at least para. [0020] of English which discloses “FIGS. 13A-C is a side view of an example of a tilt rotor mechanism in the forward, transition, and hover regimes, respectively”, *Fig. 13A illustrates propulsion system 118 in a vertical orientation and Fig. 13C illustrates propulsion system 118 in a horizontal orientation).
Regarding claim 11, English discloses A method for controlling (see at least para. [0026] of
English which discloses “the unified command system 100 includes an input mechanism 101, a flight processor 102 that receives command input 104 from the input mechanism and translates the input into control output 105, and effectors 110 that are actuated according to the control output. The system can optionally include: one or more sensors, a vehicle navigation system which determines a vehicle state and/or flight regime based on data from the one or more sensors 120, and a vehicle guidance system which determines a flightpath for the aircraft”) a tiltrotor aircraft (see at least para. [0037] of English which discloses “a tiltrotor (or tilt-prop) aircraft”), comprising:
receiving, by a flight control computer (see at least para. [0026] of English which discloses “the unified command system 100 includes an input mechanism 101, a flight processor 102 that receives command input 104 from the input mechanism and translates the input into control output 105, and effectors 110 that are actuated according to the control output … the unified command system 100 can additionally or alternatively include any other suitable components”, which collectively form a flight control computer and English discloses a flight control computer in the form of a flight processor included within a unified command system (see at least para. [0026], which discloses that the unified command system includes a flight processor that receives command input form an input mechanism and translate the input into control output for actuating effectors). Such a flight processor is a functional equivalent of a flight control computer. Also note that para. [0113] of English describes “a machine configured to receive a computer-readable medium storing computer-readable instructions”, *Examiner interprets this machine to be a flight control computer), control inputs from a first inceptor and a second inceptor (see at least para. [0051] of English which discloses “the inceptor can be the only manual control input in the cockpit or aircraft. However, other control inputs (e.g., pedals, buttons, secondary inceptors, etc.) can optionally be included in the aircraft”);
using the first inceptor inputs (see at least para. [0061] of English which discloses “wherein a first inceptor is operable in a first flight regime (e.g., hover)” and see at least para. [0061] of English which discloses “the second inceptor is operable in a second flight regime (e.g., airplane), and both inceptors are operable (e.g., in a redundant manner, in a non-redundant manner, etc.) in a transition flight regime” and see at least para. [0051] of English which discloses “the inceptor can be the only manual control input in the cockpit or aircraft. However, other control inputs (e.g., pedals, buttons, secondary inceptors, etc.) can optionally be included in the aircraft”, *English further discloses that the flight control system is configured to receive inputs (see at least para. [0071]) and includes multiple inceptors, including a first inceptor operable in a first flight regime and a second inceptor operable in a second flight regime, with both inceptors operable during a transition flight regime (see at least para. [0061). In this connection, English further discloses that additional or secondary inceptors may be provided as taught in at least para. [0051]) to command longitudinal speed (see at least para. [0096] of English which discloses “in the single-inceptor command model, longitudinal (e.g., X-axis) groundspeed can be commanded via the A-axis inceptor motion”) and acceleration of the tiltrotor aircraft (see at least para. [0096] of English which discloses “The A-axis actuation can be dynamically mapped between aircraft velocity and acceleration (e.g., wherein the A-axis commands velocity control when the aircraft is moving at near-zero velocity, and commands acceleration control”) in a hover flight mode (see at least para. [0061] of English which discloses “a first inceptor is operable in a first flight regime (e.g., hover)”, *English teaches that in hover flight mode, an inceptor commands longitudinal groundspeed and that the same inceptor dynamically commands longitudinal speed and acceleration, via a command model – see para. [0096] of English. In this connection, English clearly teaches that pilot inceptor inputs are mapped by a flight processor to “translational motion … in the longitudinal direction when the aircraft is in hover”- see para. [0099] of English. See at least para. [0096] of English which discloses “longitudinal (e.g., X-axis) groundspeed can be commanded via the A-axis inceptor motion (e.g., a single axis actuator on the inceptor, such as a wheel as shown in FIG. 6). The A-axis actuation can be dynamically mapped between aircraft velocity and acceleration”, * this expressly teaches that, in hover flight, longitudinal groundspeed id commanded via an inceptor axis, and that the same inceptor axis is dynamically mapped between velocity and acceleration. English further teaches that, in forward flight, the same inceptor axis blends to airspeed acceleration control. See at least para. [0097] of English which discloses “the A-axis inceptor motion blends between commanding groundspeed (e.g., in hover) and airspeed acceleration control (e.g., in forward flight)”. Finally see at least para. [0124] of English which discloses “inceptor motion is translated into X-translational rate control (e.g., in the hover regime) and X-acceleration and airspeed (or speed) maintenance control (e.g., in the forward flight regime”, *English teaches that a first inceptor commands longitudinal speed and acceleration, including acceleration command in forward flight).
Regarding the newly added limitation of “operating in a vector rate mode”, English does
disclose flightpath vectoring in hover and forward flight describes the task environment and coupling between attitude and flightpath (see at least para. [0039] of English which discloses “The flight regimes are each associated with a set of aircraft effectors that aerodynamically control the forces and moments on the aircraft, and the set of aircraft effectors can vary among the various flight regimes. For example, forward flight as an airplane can be largely a flightpath vectoring task wherein airplane attitude is largely coupled to the flightpath, as compared to hover which can be largely a horizontal positioning task with a vertical control component, wherein the aircraft attitude is substantially less coupled to the flightpath vector. The system and method function to automatically determine the set of effectors and effector states associated with a commanded aircraft maneuver or action demanded by the user (e.g., such that the user does not need to devote cognitive energy to identifying and commanding the set of effectors directly). As shown in FIG. 3, these flight regimes can include: vertical takeoff and landing (VTOL) or hover, wherein the aircraft yaw is controlled through nacelle tilt, and aircraft roll, pitch, and attitude are controlled through propeller pitch and motor RPM; conventional takeoff and landing (CTOL) and airplane, wherein traditional flight control surfaces are used to control the aircraft yaw, roll, pitch, and attitude (e.g., flaps, ruddervators, ailerons, propeller thrust, etc.); and transition (e.g., between forward flight as an airplane and hover or vice versa), wherein the thrust (e.g., blade pitch and motor RPM), propeller unit tilt angle, and control surfaces are used in a dynamically adjusted manner during conversion between airplane and hover flight”).
English may not explicitly disclose the newly added limitation of operating in a vector rate
mode.
However, Shue 252 teaches a multi-loop flight control architecture in which the pilot
inceptor inputs are processed through control laws to generate commanded longitudinal and vertical motion, including commanded velocity and acceleration along relevant axes (see at least para. [0081] of Shue 252 which discloses “For pilot command inputs in auto-pilot, mission, and navigation modes, the individual control laws loop design may be designed differently depending on the design requirements, such as coupled or uncoupled mode. For example, in autopilot mode, the pilot commands can be designed as coupled or uncoupled function with hold situation. Therefore, the delta stick on individual axis and airspeed regions will act differently. The pilot commands will just follow the mode switch logic to accomplish the pilot command input motions. Similarly, the commands from ground control station joysticks and aircraft inceptors will work like the delta stick functions following the control laws logic state to fly the aircraft”, *Examiner interprets this as corresponding to the claimed operation in a vector rate mode).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the method of English to include operating in a vector rate mode, as taught in Shue’252 with a reasonable expectation of success in order to reduce pilot workload and provide a more intuitive and unified command concept across hover, transition and airplane flight phases by mapping inceptor inputs to translational rate commands instead of requiring the pilot to directly manage effector by effector control.
Regarding the newly added limitation of operation in a vector rate mode, Raza teaches
an aircraft control system that maps pilot inputs to high-level speed and climb/descent-type commands under selectable control modes which confirms that the use of inceptor inputs to command translational and vertical movement is a known and predictable control-law implementation (see at least para. [0044] of Raza which discloses “an operator may utilize longitudinal inputs 308 of left-hand inceptor 302 to provide an overall vertical adjustment (e.g., adjustment in altitude) to aircraft 10. Due to inceptor 302 being at angle “A”, part of the movement of inceptor 302 matches the requested vertical movement of the aircraft (e.g., a forward and downward movement of inceptor 302 causes descent of aircraft 10). In some examples, most of the motion of inceptor 302 may match the vertical motion of the aircraft (e.g., examples where angle “A” is greater than 45 degrees). In other examples, less than half of the movement of inceptor 302 may match the corresponding vertical motion”).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to configure the tiltrotor flight control computer of English to operate in a vector rate mode in which first and second inceptors command longitudinal speed/acceleration and climb/descent rate in both hover and cruise mode because this type of rate-command outer loop control is a conventional and predictable use of known aircraft control laws to simplify pilot workload and mange flight across modes. The cited prior art already teaches flight control computers using control laws to command rate-based translational motion, so adding the operation in the vector rate mode does not add patentable distinction.
English does teach certain flight modes (see at least para. [0061] of English which discloses
“two inceptors (e.g., wherein helicopter-analogous actions are associated with a right-hand inceptor, wherein airplane-analogous actions are associated with a left-hand inceptor, vice versa, etc.). In another example, the system can include two inceptors, wherein a first inceptor is operable in a first flight regime (e.g., hover) and the second inceptor is operable in a second flight regime (e.g., airplane), and both inceptors are operable (e.g., in a redundant manner, in a non-redundant manner, etc.) in a transition flight regime”, * This is evidence of operation across hover, transition and forward flight regimes).
English may not explicitly disclose in a cruise flight mode and that the same inceptor
command semantics are preserved in both hover and cruise modes); and using the second inceptor inputs to command climb and descent rates in both hover and cruise flight modes.
However, in the same field of endeavor, Raza discloses both a cruise flight mode (see at
least para. [0022] of Raza which discloses “a cruise stage”) and a hover flight mode (see at least para. [0049] of Raza which discloses “whether the aircraft is experiencing rotor-borne flight, wing-borne flight, or a transition between rotor-borne and wing-borne flight”, *The rotor-borne flight is equivalent to hover flight mode and the wing-borne flight is equivalent to cruise flight mode), and the second inceptor inputs command climb and descent in both hover and cruise flight modes (see at least para. [0044] of Raza which discloses “longitudinal inputs 308 of left-hand inceptor 302 to provide an overall vertical adjustment (e.g., adjustment in altitude) to aircraft 10. Due to inceptor 302 being at angle “A”, part of the movement of inceptor 302 matches the requested vertical movement of the aircraft (e.g., a forward and downward movement of inceptor 302 causes descent of aircraft 10). In some examples, most of the motion of inceptor 302 may match the vertical motion of the aircraft (e.g., examples where angle “A” is greater than 45 degrees). In other examples, less than half of the movement of inceptor 302 may match the corresponding vertical motion”, * Raza teaches the inceptor motion corresponds to upward and downward aircraft movement, i.e., climb and descent).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the flight control method of English to include commands across hover and cruise flight modes, as taught by Raza with a reasonable expectation of success in order to facilitate the application of known flight control objectives (speed/acceleration and vertical rate commands) using known processor based control laws in a predictable manner to achieve intuitive pilot control across different flight plans. See para. [0044] and [0049] of Raza for motivation.
While Raza teaches commanding upward and downward aircraft movement via inceptor
inputs across rotor-borne and wing-borne flight, Raza may not explicitly teach commanding rates of climb and descent.
However, Shue’658 discloses inputs command climb and descent rates (see at least para.
[0099] of Shue’658 which discloses “the difference between a reference and vertical velocity for climb and descent commands. The reference is preferably supplied by a selector knob (or wheel) located on the FGS control panel or through a “beep” switch located on a control stick grip (preferably the power lever) that slews a reference integrator within the FGS. Rate and magnitude limits are designed on the reference consistent with the maneuver limits desired”, * This constitutes express teaching of vertical velocity as a commanded variable used for climb and descent commands, thereby supplying the claimed rate-command limitation).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the flight control method of English, as modified by Raza to include commanding rates of climb and descent as taught in Shue’658 with a reasonable expectation of success in order to improve inceptor ability to command climb/descent rates, thereby completing the claimed control law mapping for vertical movement. See para. [0099] of Shue’658 for motivation.
As discussed above, English teaches a mode-based tiltrotor control system in which different
flight regimes use different effectors and control allocations.
English may not explicitly disclose the newly added limitation of “alternatively operate in a
reversionary mode in which the vector rate mode is not allowed to continue operating”.
However, Shue 252 discloses inceptor-management and state-flow logic that selectively
passes or stops command inputs based on the applicable mode (see at least para. [0103] of Shue 252 which discloses “the total wireless commands can be finite sets as N. The action is to form an enable switching function to allow the individual command to be ON (pass through) or OFF (stop). Note that only one priority command set will be passed through and controlled by the state flow logic switching algorithm design”). Shue 658 teaches a multi-loop flight control architecture in which control-law behavior varies according to operating mode and design requirements (see at least para. [0024] of Shue 658 which discloses “The three control loop design of the present invention will robustly enlarge the stability of the aircraft control laws. Instead of using classic feedback control law, the present invention enhances the system by: (1) leaving the strongest portion of classic feedback control system; and (2) introducing two other control laws to handle the natural weakness of classic feedback control law. The present invention saves flight test periods and shortens the time required to design control laws. Use of the three control loops has been as capable of making unstable aircraft to be not only stabilized but also guided and navigated, whereas the pure classic feedback control laws cannot even stabilize the system”, *Examiner interprets this disclosure of a multi-loop flight control architecture in which aircraft control may be implemented through different outer-loop control laws, and the broader flight-control art recognizes switching between rate command and alternate control law modes based on operating conditions which is equivalent to operating in a reversionary mode that doesn’t allow the vector rate mode).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the system of English to alternatively operate in a reversionary mode in which the vector rate mode is not allowed to continue operating and possibly reverts to an alternate control law when required for safe, predictable flight, as taught in Shue 252 and Shue 658 with a reasonable expectation of success since switching between command laws and reconfiguring control authority based on operating conditions is a known and predictable design choice in aircraft control systems.
Regarding claim 12, English, as modified by Shue’252, Raza and Shue’658 discloses further
comprising: converting a signal (see at least para. [0026] of English which discloses “a flight processor 102 that receives command input 104 from the input mechanism and translates the input into control output 105, and effectors 110 that are actuated according to the control output. The system can optionally include: one or more sensors, a vehicle navigation system which determines a vehicle state and/or flight regime based on data from the one or more sensors 120, and a vehicle guidance system” and para. [0116] of English discloses “sing an input mechanism (e.g., an inceptor, a pair of inceptors, etc.) substantially as described above in relation to the system 100 but can additionally or alternatively be performed using any suitable means of obtaining input”, *English teaches the flight processor is the component that performs the conversion and the conversion is from inceptor input to commanded aircraft motion) representing a longitudinal force applied to the first inceptor into an altitude rate change (see at least para. [0095] of English which discloses “altitude) data is available, the vertical rate command can schedule a height-change rate of the aircraft”) in hover flight mode or into a flight path angle change (see at least para. [0027] of English which discloses “a user 140 (e.g., pilot, non-pilot) to control output variables of aircraft operation (e.g., aircraft actions, speed, airspeed, groundspeed, flight path, etc.) “) in cruise flight mode; converting a signal representing a longitudinal force applied to the second inceptor into a longitudinal velocity (see at least para. [0096] of English which discloses “velocity and acceleration (e.g., wherein the A-axis commands velocity control when the aircraft is moving at near-zero velocity, and commands acceleration control when further away from the zero-velocity point”) in hover flight mode or into a longitudinal acceleration in cruise flight mode; converting a signal representing a lateral force applied to the second inceptor into a lateral velocity in hover flight mode or into a roll rate in cruise flight mode; and converting a signal representing a twist force applied to the second inceptor into a yaw rate command in hover flight mode or into a sideslip command in cruise flight mode (see at least para. [0097] of English which discloses “ the motion of the inceptor along the 4 independent axes blends between controlling different aspects of the aircraft attitude and motion. In a specific example, longitudinal inceptor motion (e.g., along the X-axis) blends between commanding vertical rate (e.g., in hover) and commanding flightpath rate (e.g., in forward flight)”, *English teaches converting force based inceptor inputs into different commanded aircraft motion variables depending on flight regimes, including converting longitudinal, lateral, and twist forces into a vertical rate (hover), etc. and see para. [0096]-[0097]).
Regarding claim 13, English, as modified by Shue’252, Raza and Shue’658 discloses further
comprising: converting a signal representing a longitudinal force applied to the first inceptor into a thrust offset command, wherein forward-directed forces correspond to a thrust decrease and backward-directed forces correspond to a thrust increase (see at least para. [0130] of English which discloses “thrust availability, envelope limits, structural limits, terrain limits, etc.), according to demand prioritization. This can include preferentially controlling effectors based on a predetermined demand prioritization, even in cases wherein the user demands (e.g., provides input) actions that require deprioritized effector control. For example, in the hover regime, attitude control can be prioritized over velocities (e.g., thrust) or accelerations; in the transition regime, vertical thrust components can be prioritized over horizontal components”); converting signals from a switch on the first inceptor into a thrust bias setting; converting a signal representing a longitudinal force applied to the second inceptor into a pitch attitude command; converting a signal representing a lateral force applied to the second inceptor into a roll attitude command (see at least para. [0099] of English which discloses “the first inceptor (e.g., “roll inceptor”) can command coordinated turns (e.g., banking turns) when the aircraft is in forward flight, and yaw (e.g., heading) control when the aircraft is in hover. The second inceptor (e.g., “yaw inceptor”) can map commands to sideslip (e.g., de-coordinated heading adjustment) when the aircraft is in forward flight, and to lateral (e.g., left/right) translational control in hover”); converting a signal representing a twist force applied to the second inceptor into a yaw rate command (see at least para. [0100] of English which discloses “yaw response in the hover regime, and a blended sideslip and yaw response in the transition regime. The third input axis also optionally maps to steering during ground operations (taxiing). Preferably, the yaw response is a heading rate (yaw rate) response”); and converting signals from a switch on the second inceptor into a conversion command (see at least para. [0116] of English which discloses “convert the user's intention into an input that can be processed (e.g., by a flight processor) into control outputs (e.g., for actuating aircraft effectors). Block S210 is preferably performed using an input mechanism (e.g., an inceptor, a pair of inceptors, etc.) substantially as described above in relation to the system 100 but can additionally or alternatively be performed using any suitable means of obtaining input (e.g., audio commands”).
Regarding claim 14, English, as modified by Shue’252, Raza and Shue’658 discloses further
comprising: converting a signal representing a longitudinal force applied to the first inceptor into an altitude rate change (see at least para. [0095] of English which discloses “altitude) data is available, the vertical rate command can schedule a height-change rate of the aircraft”) in hover flight mode or into a flight path angle change (see at least para. [0027] of English which discloses “a user 140 (e.g., pilot, non-pilot) to control output variables of aircraft operation (e.g., aircraft actions, speed, airspeed, groundspeed, flight path, etc.) “) in cruise flight mode; converting a signal representing a longitudinal force applied to the second inceptor into a longitudinal velocity (see at least para. [0096] of English which discloses “velocity and acceleration (e.g., wherein the A-axis commands velocity control when the aircraft is moving at near-zero velocity, and commands acceleration control when further away from the zero-velocity point”) in hover flight mode or into a longitudinal acceleration in cruise flight mode; converting a signal representing a lateral force applied to the second inceptor into a lateral velocity in hover flight mode or into a roll rate in cruise flight mode; and converting signals representing forces applied to floor pedals into a yaw rate command in hover flight mode or into a sideslip command in cruise flight mode (see at least para. [0097] of English which discloses “ the motion of the inceptor along the 4 independent axes blends between controlling different aspects of the aircraft attitude and motion. In a specific example, longitudinal inceptor motion (e.g., along the X-axis) blends between commanding vertical rate (e.g., in hover) and commanding flightpath rate (e.g., in forward flight)”, *English teaches converting force based inceptor inputs into different commanded aircraft motion variables depending on flight regimes, including converting longitudinal, lateral, and twist forces into a vertical rate (hover), etc. and see para. [0096]-[0097]).
Regarding claim 15, English, as modified by Shue’252, Raza and Shue’658 discloses further
comprising: converting a signal representing a longitudinal force applied to the first inceptor into a longitudinal velocity in hover flight mode or into a longitudinal acceleration in cruise flight mode; converting a signal representing a longitudinal force applied to the second inceptor into; an altitude rate change (see at least para. [0095] of English which discloses “altitude) data is available, the vertical rate command can schedule a height-change rate of the aircraft”) in hover flight mode or into a flight path angle change (see at least para. [0027] of English which discloses “a user 140 (e.g., pilot, non-pilot) to control output variables of aircraft operation (e.g., aircraft actions, speed, airspeed, groundspeed, flight path, etc.) “) in cruise flight mode; converting a signal representing a lateral force applied to the second inceptor into a lateral velocity in hover flight mode or into a roll rate in cruise flight mode; and converting a signal representing a twist force applied to the second inceptor into a yaw rate command (see at least para. [0100] of English which discloses “yaw response in the hover regime, and a blended sideslip and yaw response in the transition regime. The third input axis also optionally maps to steering during ground operations (taxiing). Preferably, the yaw response is a heading rate (yaw rate) response”) in hover flight mode or into a sideslip command in cruise flight mode (see at least para. [0094] of English which discloses “the single-inceptor commands sideslip. Z-twist inceptor input can command aircraft sideslip by pointing the nose of the aircraft in the direction of the inceptor twist. Such sideslip commands can change the heading of the aircraft without changing the flightpath direction, because the flight processor automatically compensates for the sideslip by actuating a combination of effectors to induce the countervailing bank needed to prevent a bank turn. In a specific variant, the Z-twist inceptor input can command sideslip below a threshold airspeed. Above the threshold airspeed, Z-twist inceptor input can be ignored or otherwise suitably used to generate control output”).
Regarding claim 16, English, as modified by Shue’252, Raza and Shue’658 discloses further
comprising: converting a signal representing a longitudinal force applied to the first inceptor into a longitudinal velocity in hover flight mode or into a longitudinal acceleration in cruise flight mode; converting a signal representing a longitudinal force applied to the second inceptor into; an altitude rate change (see at least para. [0095] of English which discloses “altitude) data is available, the vertical rate command can schedule a height-change rate of the aircraft”) in hover flight mode or into a flight path angle change (see at least para. [0027] of English which discloses “a user 140 (e.g., pilot, non-pilot) to control output variables of aircraft operation (e.g., aircraft actions, speed, airspeed, groundspeed, flight path, etc.) “) in cruise flight mode; converting a signal representing a lateral force applied to the second inceptor into a lateral velocity in hover flight mode or into a roll rate in cruise flight mode; and converting signals representing forces applied to floor pedals into a yaw rate command in hover flight mode or into a sideslip command in cruise flight mode (see at least para. [0094] of English which discloses “the single-inceptor commands sideslip. Z-twist inceptor input can command aircraft sideslip by pointing the nose of the aircraft in the direction of the inceptor twist. Such sideslip commands can change the heading of the aircraft without changing the flightpath direction, because the flight processor automatically compensates for the sideslip by actuating a combination of effectors to induce the countervailing bank needed to prevent a bank turn. In a specific variant, the Z-twist inceptor input can command sideslip below a threshold airspeed. Above the threshold airspeed, Z-twist inceptor input can be ignored or otherwise suitably used to generate control output”).
Regarding claim 17, English, as modified by Shue’252, Raza and Shue’658 discloses further
comprising: converting a signal representing a longitudinal force applied to the first inceptor into a thrust offset command, wherein forward-directed forces correspond to a thrust increase and backward-directed forces correspond to a thrust decrease; converting signals from a switch on the first inceptor into a thrust bias setting; converting a signal representing a longitudinal force applied to the second inceptor into a pitch attitude command; converting a signal representing a lateral force applied to the second inceptor into a roll attitude command; converting a signal representing a twist force applied to the second inceptor into a yaw rate command (see at least para. [0100] of English which discloses “yaw response in the hover regime, and a blended sideslip and yaw response in the transition regime. The third input axis also optionally maps to steering during ground operations (taxiing). Preferably, the yaw response is a heading rate (yaw rate) response”); and converting signals from a switch on the second inceptor into a conversion command (see at least para. [0116] of English which discloses “convert the user's intention into an input that can be processed (e.g., by a flight processor) into control outputs (e.g., for actuating aircraft effectors). Block S210 is preferably performed using an input mechanism (e.g., an inceptor, a pair of inceptors, etc.) substantially as described above in relation to the system 100 but can additionally or alternatively be performed using any suitable means of obtaining input (e.g., audio commands”).
Regarding claim 18, English, as modified by Shue’252, Raza and Shue’658 discloses further
comprising: transiting from longitudinal velocity and lateral velocity changes in hover flight mode to longitudinal acceleration changes and roll rate changes (see at least para. [0097] of English which discloses “airspeed acceleration control (e.g., in forward flight); and the pitch attitude of the aircraft can be gradually de-coupled from the flightpath control as the aircraft slows from forward flight into hover”, *English explicitly describes transitions bounded by airspeed and flight condition thresholds) in cruise flight mode over a defined ground speed range (see at least para. [0131] of English which discloses “velocity-related control outputs can be controlled based on an “acceleration well”, wherein the ground speed automatically gradually reduces to zero when the aircraft is moving below a threshold airspeed (e.g., in the hover regime) without further control inputs“).
Regarding claim 19, English, as modified by Shue’252, Raza and Shue’658 discloses further
comprising: transitioning from altitude rate changes and yaw rate changes in hover flight mode to flight path angle changes and sideslip changes in cruise flight mode at a first airspeed when the tiltrotor aircraft is accelerating, and transitioning from flight path angle changes and sideslip changes in cruise flight mode to altitude rate changes and yaw rate changes in hover flight mode at a second airspeed when the tiltrotor aircraft is decelerating, wherein the second airspeed is lower than the first airspeed (see at least para. [0097] of English which discloses “airspeed acceleration control (e.g., in forward flight); and the pitch attitude of the aircraft can be gradually de-coupled from the flightpath control as the aircraft slows from forward flight into hover. The blending of each of the aforementioned command axes is preferably scheduled against the airspeed of the aircraft (e.g., wherein commands are mapped entirely to hover behavior at an airspeed substantially equal to zero and mapped entirely to airplane behavior at an airspeed greater than the minimum stall speed, and mapped to transitional control outputs by the flight processor in proportion to the airspeed between zero and the minimum stall speed)”).
Regarding claim 20, English discloses An tiltrotor aircraft (see at least para. [0037] of English
which discloses “a tiltrotor (or tilt-prop) aircraft”), comprising: a first inceptor (see at least para. [0061] of English which discloses “wherein a first inceptor is operable in a first flight regime (e.g., hover)”) and a second inceptor (see at least para. [0061] of English which discloses “the second inceptor is operable in a second flight regime (e.g., airplane), and both inceptors are operable (e.g., in a redundant manner, in a non-redundant manner, etc.) in a transition flight regime” and see at least para. [0051] of English which discloses “the inceptor can be the only manual control input in the cockpit or aircraft. However, other control inputs (e.g., pedals, buttons, secondary inceptors, etc.) can optionally be included in the aircraft”, *English further discloses that the flight control system is configured to receive inputs (see at least para. [0071]) and includes multiple inceptors, including a first inceptor operable in a first flight regime and a second inceptor operable in a second flight regime, with both inceptors operable during a transition flight regime (see at least para. [0061). In this connection, English further discloses that additional or secondary inceptors may be provided as taught in at least para. [0051]); a first set of propulsion systems (Fig. 13A-13C, 118 and see at least para. [0037] of English which discloses “a plurality of aircraft propulsion systems 118”) configured to tilt (see at least para. [0109] of English which discloses “propulsion units 118 (e.g., tiltable propellers with variable blade pitch, an example is shown in FIGS. 13A-C), and any other suitable control surfaces and/or actuatable mechanisms that can affect the flight of the aircraft”) between a first position when the tiltrotor aircraft is in a hover mode (see Figs. 13A-13C and see at least para. [0020] of English which discloses “an example of a tilt rotor mechanism in the forward, transition, and hover regimes, respectively”) and a second position (see at least para. [0020] of English which discloses “FIGS. 13A-C is a side view of an example of a tilt rotor mechanism in the forward, transition, and hover regimes, respectively”, *Fig. 13A illustrates propulsion system 118 in a vertical orientation and Fig. 13C illustrates propulsion system 118 in a horizontal orientation) when the tiltrotor aircraft is in a mode; a flight control system (see at least para. [0039] of English which discloses “The system 100 and method 200 can be used in relation to various flight regimes of the transition aircraft (e.g., tilt-prop aircraft, tiltrotor aircraft, tilt thrust aircraft, etc.)” configured to control the first and second sets of propulsion systems in response to inputs from the first and second inceptors (see at least para. [0051] of English which discloses “The input mechanism can include one or more inceptors, a display, and any other suitable interface components. In a specific example, the inceptor can be the only manual control input in the cockpit or aircraft. However, other control inputs (e.g., pedals, buttons, secondary inceptors, etc.) can optionally be included in the aircraft”), the flight control computer (see at least para. [0026] of English which discloses “the unified command system 100 includes an input mechanism 101, a flight processor 102 that receives command input 104 from the input mechanism and translates the input into control output 105, and effectors 110 that are actuated according to the control output … the unified command system 100 can additionally or alternatively include any other suitable components”, which collectively form a flight control computer and English discloses a flight control computer in the form of a flight processor included within a unified command system (see at least para. [0026], which discloses that the unified command system includes a flight processor that receives command input form an input mechanism and translate the input into control output for actuating effectors). Such a flight processor is a functional equivalent of a flight control computer. Also note that para. [0113] of English describes “a machine configured to receive a computer-readable medium storing computer-readable instructions”, *Examiner interprets this machine to be a flight control computer) adapted to: convert a signal representing a longitudinal force applied to the first inceptor (see at least para. [0026] of English which discloses “a flight processor 102 that receives command input 104 from the input mechanism and translates the input into control output 105, and effectors 110 that are actuated according to the control output. The system can optionally include: one or more sensors, a vehicle navigation system which determines a vehicle state and/or flight regime based on data from the one or more sensors 120, and a vehicle guidance system” and para. [0116] of English discloses “sing an input mechanism (e.g., an inceptor, a pair of inceptors, etc.) substantially as described above in relation to the system 100 but can additionally or alternatively be performed using any suitable means of obtaining input”, *English teaches the flight processor is the component that performs the conversion and the conversion is from inceptor input to commanded aircraft motion) into an altitude rate change (see at least para. [0095] of English which discloses “altitude) data is available, the vertical rate command can schedule a height-change rate of the aircraft”) in hover flight mode or into a flight path angle change in cruise flight mode; convert a signal (see at least para. [0116] of English which discloses “convert the user's intention into an input that can be processed (e.g., by a flight processor) into control outputs (e.g., for actuating aircraft effectors). Block S210 is preferably performed using an input mechanism (e.g., an inceptor, a pair of inceptors, etc.) substantially as described above in relation to the system 100 but can additionally or alternatively be performed using any suitable means of obtaining input”) representing a longitudinal force applied to the second inceptor into a longitudinal velocity in hover flight mode or into a longitudinal acceleration in cruise flight mode (see at least para. [0039] of English which discloses “a set of aircraft effectors that aerodynamically control the forces and moments on the aircraft, and the set of aircraft effectors can vary among the various flight regimes. For example, forward flight as an airplane can be largely a flightpath vectoring task wherein airplane attitude is largely coupled to the flightpath, as compared to hover which can be largely a horizontal positioning task with a vertical control component, wherein the aircraft attitude is substantially less coupled to the flightpath vector”) ; convert a signal representing a lateral force applied to the second inceptor into a lateral velocity in hover flight mode or into a roll rate in cruise flight mode; and convert a signal representing a twist force applied (see at least para. [0094] of English which discloses “twist (e.g., along the Z-axis) input to the single-inceptor commands sideslip. Z-twist inceptor input can command aircraft sideslip by pointing the nose of the aircraft in the direction of the inceptor twist. Such sideslip commands can change the heading of the aircraft without changing the flightpath direction, because the flight processor automatically compensates for the sideslip by actuating a combination of effectors to induce the countervailing bank needed to prevent a bank turn. In a specific variant, the Z-twist inceptor input can command sideslip below a threshold airspeed”) to the second inceptor into a yaw rate command in hover flight mode or into a sideslip command (see at least para. [0094] of English which discloses “sideslip commands can change the heading of the aircraft without changing the flightpath direction”) in cruise flight mode.
Regarding the newly added limitation of “operate in a vector rate mode”, English does
disclose flightpath vectoring in hover and forward flight describes the task environment and coupling between attitude and flightpath (see at least para. [0039] of English which discloses “The flight regimes are each associated with a set of aircraft effectors that aerodynamically control the forces and moments on the aircraft, and the set of aircraft effectors can vary among the various flight regimes. For example, forward flight as an airplane can be largely a flightpath vectoring task wherein airplane attitude is largely coupled to the flightpath, as compared to hover which can be largely a horizontal positioning task with a vertical control component, wherein the aircraft attitude is substantially less coupled to the flightpath vector. The system and method function to automatically determine the set of effectors and effector states associated with a commanded aircraft maneuver or action demanded by the user (e.g., such that the user does not need to devote cognitive energy to identifying and commanding the set of effectors directly). As shown in FIG. 3, these flight regimes can include: vertical takeoff and landing (VTOL) or hover, wherein the aircraft yaw is controlled through nacelle tilt, and aircraft roll, pitch, and attitude are controlled through propeller pitch and motor RPM; conventional takeoff and landing (CTOL) and airplane, wherein traditional flight control surfaces are used to control the aircraft yaw, roll, pitch, and attitude (e.g., flaps, ruddervators, ailerons, propeller thrust, etc.); and transition (e.g., between forward flight as an airplane and hover or vice versa), wherein the thrust (e.g., blade pitch and motor RPM), propeller unit tilt angle, and control surfaces are used in a dynamically adjusted manner during conversion between airplane and hover flight”).
English may not explicitly disclose the newly added limitation of “operate in a vector rate
Mode”.
However, Shue 252 teaches a multi-loop flight control architecture in which the pilot
inceptor inputs are processed through control laws to generate commanded longitudinal and vertical motion, including commanded velocity and acceleration along relevant axes (see at least para. [0081] of Shue 252 which discloses “For pilot command inputs in auto-pilot, mission, and navigation modes, the individual control laws loop design may be designed differently depending on the design requirements, such as coupled or uncoupled mode. For example, in autopilot mode, the pilot commands can be designed as coupled or uncoupled function with hold situation. Therefore, the delta stick on individual axis and airspeed regions will act differently. The pilot commands will just follow the mode switch logic to accomplish the pilot command input motions. Similarly, the commands from ground control station joysticks and aircraft inceptors will work like the delta stick functions following the control laws logic state to fly the aircraft”, *Examiner interprets this as corresponding to the claimed operation in a vector rate mode).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the system of English to operate in a vector rate mode, as taught in Shue’252 with a reasonable expectation of success in order to reduce pilot workload and provide a more intuitive and unified command concept across hover, transition and airplane flight phases by mapping inceptor inputs to translational rate commands instead of requiring the pilot to directly manage effector by effector control.
Regarding the newly added limitation of operation in a vector rate mode, Raza teaches
an aircraft control system that maps pilot inputs to high-level speed and climb/descent-type commands under selectable control modes which confirms that the use of inceptor inputs to command translational and vertical movement is a known and predictable control-law implementation (see at least para. [0044] of Raza which discloses “an operator may utilize longitudinal inputs 308 of left-hand inceptor 302 to provide an overall vertical adjustment (e.g., adjustment in altitude) to aircraft 10. Due to inceptor 302 being at angle “A”, part of the movement of inceptor 302 matches the requested vertical movement of the aircraft (e.g., a forward and downward movement of inceptor 302 causes descent of aircraft 10). In some examples, most of the motion of inceptor 302 may match the vertical motion of the aircraft (e.g., examples where angle “A” is greater than 45 degrees). In other examples, less than half of the movement of inceptor 302 may match the corresponding vertical motion”).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to configure the tiltrotor flight control computer of English to operate in a vector rate mode in which first and second inceptors command longitudinal speed/acceleration and climb/descent rate in both hover and cruise mode because this type of rate-command outer loop control is a conventional and predictable use of known aircraft control laws to simplify pilot workload and mange flight across modes. The cited prior art already teaches flight control computers using control laws to command rate-based translational motion, so adding the operation in the vector rate mode does not add patentable distinction.
English does disclose a plurality of aircraft propulsion systems in para. [0037] and that
different effectors may be used in different flight regimes as taught in para. [0039] and see at least para. [0037] of English which discloses “propulsion systems 118 (e.g., rotor assemblies, rotor systems, etc.), operable between a forward arrangement (an example is shown in FIG. 16) and a hover arrangement (an example is shown in FIG. 15). However, the rotorcraft can alternatively be any other suitable rotorcraft or vehicle propelled by rotors”).
English may not explicitly disclose a second set of propulsion systems. configured to remain
in a fixed orientation.
However, Section 2144.04 of the MPEP sets forth that the mere duplication of parts has no
patentable significance unless a new and unexpected result is produced. See In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960).
In this case, it would have been obvious to one of ordinary skill in the art before the
effective filing date of the claimed invention to configure a first subset of the plurality of propulsion systems to tilt between hover and cruise positions and to configure a second subset of the plurality to remain in a fixed orientation, as a predictable variation in tiltrotor aircraft design. Further, English discloses a plurality of propulsion systems, and it would have been obvious to configure a first subset to tilt and a second subset to remain fixed a s a predictable design choice in tiltrotor aircraft.
English may not explicitly disclose a fuselage; a cockpit within the fuselage; a wing
connected to the fuselage; and a cruise mode.
However, in the same field of endeavor, Shue’252 discloses a fuselage (Fig. 1, 130 and see at
least para. [0018] which discloses “a fuselage 130”); a cockpit (Fig. 1 illustrates a cockpit and para. [0049] describes “the pilot is on-board in the cockpit”) within the fuselage; a wing (Fig. 1, 150 and see at least para. [0018] of Shue’252 which discloses “a wing 150”) connected to the fuselage (see at least para. [0020] of Shue’252 which discloses “Fuselage 130 represents the main body of rotorcraft 100 and may be coupled to rotor system 110 (e.g., via wing 150)”).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the aircraft to explicitly include a fuselage; a cockpit within the fuselage; a wing connected to the fuselage, as described in Shue’252 with a reasonable expectation of success in order to improve the aircraft design do that it is more aerodynamic.
English, as modified by Shue‘252, may not explicitly disclose in a cruise mode.
However, in the same field of endeavor, Raza discloses both a cruise flight mode (see at
least para. [0022] of Raza which discloses “a cruise stage”) and a hover flight mode (see at least para. [0049] of Raza which discloses “whether the aircraft is experiencing rotor-borne flight, wing-borne flight, or a transition between rotor-borne and wing-borne flight”, *The rotor-borne flight is equivalent to hover flight mode and the wing-borne flight is equivalent to cruise flight mode).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the flight control system of English, as modified by Shue’252, to include commands across hover and cruise flight modes, as taught by Raza with a reasonable expectation of success in order to facilitate the application of known flight control objectives (speed/acceleration and vertical rate commands) using known processor based control laws in a predictable manner to achieve intuitive pilot control across different flight plans. See para. [0044] and [0049] of Raza for motivation.
As discussed above, English teaches a mode-based tiltrotor control system in which different
flight regimes use different effectors and control allocations.
English may not explicitly disclose the newly added limitation of “alternatively operate in a
reversionary mode in which the vector rate mode is not allowed to continue operating”.
However, Shue 252 discloses inceptor-management and state-flow logic that selectively
passes or stops command inputs based on the applicable mode (see at least para. [0103] of Shue 252 which discloses “the total wireless commands can be finite sets as N. The action is to form an enable switching function to allow the individual command to be ON (pass through) or OFF (stop). Note that only one priority command set will be passed through and controlled by the state flow logic switching algorithm design”). Shue 658 teaches a multi-loop flight control architecture in which control-law behavior varies according to operating mode and design requirements (see at least para. [0024] of Shue 658 which discloses “The three control loop design of the present invention will robustly enlarge the stability of the aircraft control laws. Instead of using classic feedback control law, the present invention enhances the system by: (1) leaving the strongest portion of classic feedback control system; and (2) introducing two other control laws to handle the natural weakness of classic feedback control law. The present invention saves flight test periods and shortens the time required to design control laws. Use of the three control loops has been as capable of making unstable aircraft to be not only stabilized but also guided and navigated, whereas the pure classic feedback control laws cannot even stabilize the system”, *Examiner interprets this disclosure of a multi-loop flight control architecture in which aircraft control may be implemented through different outer-loop control laws, and the broader flight-control art recognizes switching between rate command and alternate control law modes based on operating conditions which is equivalent to operating in a reversionary mode that doesn’t allow the vector rate mode).
It would have been obvious to one of ordinary skill in the art before the effective filing date
of the claimed invention to modify the system of English to alternatively operate in a reversionary mode in which the vector rate mode is not allowed to continue operating and possibly reverts to an alternate control law when required for safe, predictable flight, as taught in Shue 252 and Shue 658 with a reasonable expectation of success since switching between command laws and reconfiguring control authority based on operating conditions is a known and predictable design choice in aircraft control systems.
Additional Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Ross (US 2019/0031371 A1) discloses a tiltrotor aircraft including providing a lift propulsion module; providing a fuselage; and connecting the lift propulsion module to the fuselage; wherein the lift propulsion module is configured to be physically interchangeable with different types of fuselages and a lift propulsion module 110 that includes a first rotor system 112, a second rotor system 114, and a wing member 116. The first rotor system 112 is located on an end portion of a first side of the wing member 116, while second rotor system 114 is located an end portion of a second side of the wing member 116. The first rotor system 112 and second rotor system 114 are substantially symmetric of each other about the fuselage 101. The first rotor system 112 and the second rotor system 114 each include a plurality of rotor blades 118 and 119 coupled to a rotor hub assembly 113 and 115, respectively. Oliver (US 8,708,273) discloses a vertical takeoff and landing aircraft comprising a fuselage, a plurality of wings attached to the fuselage, a first rotatable propulsion unit attached to a first side of each of the plurality of wings and a second rotatable propulsion unit attached to a second side of each of the plurality of wings. Each rotatable propulsion unit comprises a propeller and a propeller hub. Moreover, each propeller comprises a plurality of blades, where each of the plurality of blades has a hole along its longitudinal axis. Each propeller also comprise a plurality of rotatable rods, where each of the plurality of rods extends into the hole of a corresponding one of the plurality of blades. The proximal end of each of the plurality of blades is enclosed in or adjacent to the propeller hub and rotatable around the corresponding one of the plurality of rotatable rods. The distal end of each of the plurality of rods is fixed to a distal end of the corresponding one of the plurality of blades
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANA IVEY whose telephone number is (313)446-4896. The examiner can normally be reached 9-5:30 EST Monday-Friday.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jelani Smith can be reached at 571-270-3969. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/DANA D IVEY/Examiner, Art Unit 3662
/D.D.I/June 24, 2026
/JELANI A SMITH/Supervisory Patent Examiner, Art Unit 3662
Prosecution Insights