DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Arguments
Applicant's arguments filed 11/20/2025 have been fully considered but they are not persuasive.
Applicant argues on pages 9-10 of the submitted arguments that the claimed invention integrates the claimed abstract idea into a practical application. Examiner disagrees with Applicant’s arguments. The claimed invention merely calculates forces, but there is no claim made regarding how this data is used. The sensors and robot arm are each claimed at a high level of generality. Applicant states that the method is directed to a “specific robot arm,” but the robot arm is only claimed generically (“comprising a plurality of links connected in sequence and a plurality of joints, the links being connected by the joints, a six degrees of freedom (6-DOF) force and torque sensor being mounted on the joint at each end of at least part of the links”). The claimed configuration of the robot is notoriously old and well-known in the art, and the claim language provides no additional differentiation to show how the robotic structure is differentiable from another robot of the same construction.
If applicant were to amend the claims to include a step of controlling the robot by utilizing the determined external force data, the rejection may be overcome.
On pages 11-12, Applicant argues that Vorndamme does not teach the claimed invention, alleging that Vorndamme’s sensors are arbitrarily distributed. Applicant further arguges that Vorndamme’s algorithm recursively calculates parameters for each link in the kinematic chain, while the claimed invention calculates external force independently using only parameters of the target link itself, without relying on recursion data from other links. Examiner notes that while Vorndamme does state that the sensors are arbitrarily distributed, Vorndamme states explicitly that one example of distributing the sensors includes sensors at each joint (as shown in the previous office action). Therefore, Vorndamme anticipates this limitation. Additionally, there is nothing in the currently provided claim language that precludes the use of recursion, and the claim does not limit the calculation using ONLY parameters of the target link itself. In fact, Applicant’s disclosure extensively discusses the use of recursive algorithms in at least [0014], [0060]-[0061], and [0072]-[0077]. As shown in the previous office action and the rejections to follow, Vorndamme’s recursive algorithm includes the parameters of the link itself, and therefore anticipates the claimed invention.
Claim Rejections - 35 USC § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claims 1-20 are rejected under 35 U.S.C. 101 because the claimed invention is directed to an abstract idea without significantly more.
101 Analysis – Step 1
Claim 1 is directed to a method for determining an external force applied to a robotic arm. Therefore, claim 1 is within at least one of the four statutory categories.
101 Analysis – Step 2A, Prong I
Regarding Prong I of the Step 2A analysis in the 2019 PEG, the claims are to be analyzed to determine whether they recite subject matter that falls within one of the follow groups of abstract ideas: a) mathematical concepts, b) certain methods of organizing human activity, and/or c) mental processes.
Independent claim 1 includes limitations that recite an abstract idea (emphasized below) and will be used as a representative claim for the remainder of the 101 rejection. Claim 1 recites:
A method for determining an external force applied to a robotic arm,
the robotic arm comprising a plurality of links connected in sequence and a plurality of joints,
the links being connected by the joints,
a six degrees of freedom (6-DOF) force and torque sensor being mounted on the joint at each end of at least part of the links,
the 6-DOF force and torque sensor being configured to detect forces and torques applied to the corresponding joint,
wherein the method comprises:
acquiring inertial property parameters of each link, the inertial property parameters comprising a mass, a center of mass, and a rotational inertia of each link;
determining motion state parameters of each link, the motion state parameters comprising an angular velocity, an angular acceleration, and a linear acceleration of each link;
determining an inertial force and an inertial torque at the center of mass of a target link according to the motion state parameters and the inertial property parameters of each link;
acquiring forces and torques between two ends of the target link and the corresponding joints respectively by the 6-DOF force and torque sensors; and
determining an external force applied to the target link according to the inertial force and the inertial torque at the center of mass of the target link, and the forces and the torques between the two ends of the target link and the corresponding joints.
The examiner submits that the foregoing bolded limitation(s) constitute a “mental process” because under its broadest reasonable interpretation, the claim covers performance of the limitation in the human mind. For example, the limitation of “determining an inertial force and an inertial torque…” and “determining an external force … according to the inertial force and the inertial torque…” in the context of this claim encompasses a human performing a force and torque analysis of the robot linkage using gathered data.
101 Analysis – Step 2A, Prong II
Regarding Prong II of the Step 2A analysis in the 2019 PEG, the claims are to be analyzed to determine whether the claim, as a whole, integrates the abstract into a practical application. As noted in the 2019 PEG, it must be determined whether any additional elements in the claim beyond the abstract idea integrate the exception into a practical application in a manner that imposes a meaningful limit on the judicial exception. The courts have indicated that additional elements merely using a computer to implement an abstract idea, adding insignificant extra solution activity, or generally linking use of a judicial exception to a particular technological environment or field of use do not integrate a judicial exception into a “practical application.”
In the present case, the additional limitations beyond the above-noted abstract idea are as follows (where the underlined portions are the “additional limitations” while the bolded portions continue to represent the “abstract idea”):
A method for determining an external force applied to a robotic arm,
the robotic arm comprising a plurality of links connected in sequence and a plurality of joints,
the links being connected by the joints,
a six degrees of freedom (6-DOF) force and torque sensor being mounted on the joint at each end of at least part of the links,
the 6-DOF force and torque sensor being configured to detect forces and torques applied to the corresponding joint,
wherein the method comprises:
acquiring inertial property parameters of each link, the inertial property parameters comprising a mass, a center of mass, and a rotational inertia of each link;
determining motion state parameters of each link, the motion state parameters comprising an angular velocity, an angular acceleration, and a linear acceleration of each link;
determining an inertial force and an inertial torque at the center of mass of a target link according to the motion state parameters and the inertial property parameters of each link;
acquiring forces and torques between two ends of the target link and the corresponding joints respectively by the 6-DOF force and torque sensors; and
determining an external force applied to the target link according to the inertial force and the inertial torque at the center of mass of the target link, and the forces and the torques between the two ends of the target link and the corresponding joints.
For the following reason(s), the examiner submits that the above identified additional limitations do not integrate the above-noted abstract idea into a practical application.
Regarding the additional limitations of “acquiring inertial property parameters of each link…”, “…detect forces and torques applied to the corresponding joint…”, and “acquiring forces and torques between two ends of the target link and the corresponding joints…”, Examiner submits that these limitations are insignificant extra-solution activities that merely use a generic sensor (e.g., 6-DOF force and torque sensor) or other non-specified measuring apparatus (in the case of motion state parameters) to perform data gathering. The 6-DOF force and torque sensor is recited at a high level of generality and is operating in its ordinary capacity and does not use the judicial exception in a manner that imposes meaningful limit on the judicial exception, such that the claim is more than a drafting effort designed to monopolize the exception. Likewise, the robot to which the method is applied is also recited at a high level of generality.
Thus, taken alone, the additional elements do not integrate the abstract idea into a practical application. Further, looking at the additional limitation(s) as an ordered combination or as a whole, the limitation(s) add nothing that is not already present when looking at the elements taken individually. For instance, there is no indication that the additional elements, when considered as a whole, reflect an improvement in the functioning of a computer or an improvement to another technology or technical field, apply or use the above-noted judicial exception to effect a particular treatment or prophylaxis for a disease or medical condition, implement/use the above-noted judicial exception with a particular machine or manufacture that is integral to the claim, effect a transformation or reduction of a particular article to a different state or thing, or apply or use the judicial exception in some other meaningful way beyond generally linking the use of the judicial exception to a particular technological environment, such that the claim as a whole is not more than a drafting effort designed to monopolize the exception. Accordingly, the additional limitations do not integrate the abstract idea into a practical application because it does not impose any meaningful limits on practicing the abstract idea.
101 Analysis – Step 2B
Regarding Step 2B of the Revised Guidance, representative independent claim 1 does not include additional elements (considered both individually and as an ordered combination) that are sufficient to amount to significantly more than the judicial exception for the same reasons to those discussed above with respect to determining that the claim does not integrate the abstract idea into a practical application. As discussed above with respect to integration of the abstract idea into a practical application, the additional elements of detecting forces using the 6-DOF force and torque sensors amounts to mere data gathering applied to a general class of sensors (insignificant extra-solution activity).
Further, a conclusion that an additional element is insignificant extra-solution activity in Step 2A should be re-evaluated in Step 2B to determine if they are more than what is well-understood, routine, conventional activity in the field. The above limitations regarding force detection are routine, well understood, and conventional activity in the field. Additionally, the robotic arm claimed is a generic robotic arm commonly used in the field. It is common to utilize robotic arms comprising links, with sensors included in each joint (see at least Vornedamme in the rejections to follow), and there are many configurations to such a robot. The specification does not provide any indication that the robot is anything other than a conventional robot, nor does the specification indicate that the sensor is anything other than a conventional sensor.
Claims 9 and 17 claim substantially the same subject matter, but include generic computing hardware to execute the method. Accordingly, the additional limitations do not integrate the abstract idea into a practical application.
Dependent claims 2, 10 and 18 introduce additional insignificant extra-solution activity and fail to integrate the abstract idea into a practical application.
Dependent claims 3 and 11 introduce additional insignificant extra-solution activity and fail to integrate the abstract idea into a practical application.
Dependent claims 4 and 12 introduce additional abstract ideas and additional insignificant extra-solution activity, and fail to integrate the abstract idea into a practical application.
Dependent claims 5, 13 and 19 introduce additional abstract ideas and additional insignificant extra-solution activity, and fail to integrate the abstract idea into a practical application.
Dependent claims 6, 14 and 20 introduce additional abstract ideas and additional insignificant extra-solution activity, and fail to integrate the abstract idea into a practical application.
Dependent claims 7 and 15 introduce additional abstract ideas and additional insignificant extra-solution activity, and fail to integrate the abstract idea into a practical application.
Dependent claims 8 and 16 introduce additional abstract ideas and additional insignificant extra-solution activity, and fail to integrate the abstract idea into a practical application.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 1-2, 4-7, 9-10, 12-15, and 17-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Vorndamme ("Collision detection, isolation and identification for humanoids," 2017)
Claim 1
Vorndamme teaches
A method for determining an external force applied to a robotic arm,
the robotic arm comprising a plurality of links connected in sequence and a plurality of joints, the links being connected by the joints,
EXAMINER NOTE: See Fig. 2. The robot comprises arms, the arms comprising links and joints connected in a sequence.
a six degrees of freedom (6-DOF) force and torque sensor being mounted on the joint at each end of at least part of the links,
(Vorndamme - [p. 4754, col 2, para. 2 thru p.4755, col 1, ln 6] … In summary, the main contributions of this paper are … a new real-time method for acceleration estimation and load compensation in humanoid robots for force/torque sensors that are arbitrarily located in the kinematic robot chain …
[p.4757, col 1, ln 11-14] For multiple sensors in a kinematic chain (e.g. in each joint), the compensation wrenches can be calculated recursively to avoid
multiple calculations, see Algorithm 1.
[p.4756, col 2, para. 2] Equations (13) and (14) result in the sensed external wrench
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I3 denotes the three dimensional unit matrix, g the Cartesian gravity vector, rDS the vector from the center of mass of the inertia attached to the sensor to the sensor and 0 the zero matrix of suitable size.)
EXAMINER NOTE: Vorndamme states that the sensors are arbitrarily placed in the kinematic chain, and that in some cases they may be placed in each joint. While there is no explicit statement that the sensors act in six axes, it may be gleaned from equation 16 above that the measurements are taken in six axes (i.e. 3 axes of force and 3 axes of torques) based on the dimensionality of Is. Additionally, Figure 3 shows three coordinate axes (see annotated Fig. 3 below), each of which may correspond to a component of force and a component of torque (six components of a wrench)
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the 6-DOF force and torque sensor being configured to detect forces and torques applied to the corresponding joint,
EXAMINER NOTE: See at least equations 13-16 and the discussion thereof on p.4756, col 2. It is clear that the force/torque sensors are used to detect forces and torques.
wherein the method comprises:
acquiring inertial property parameters of each link, the inertial property parameters comprising a mass, a center of mass, and a rotational inertia of each link;
EXAMINER NOTE: See Fig. 3. For the computations that follow, Vorndamme obtains the mass (m_D), center of mass (r_D), and moment of inertia (I_D) of each body (link) to be analyzed.
determining motion state parameters of each link, the motion state parameters comprising
an angular velocity,
(Vorndamme - [p.4755, col 2, ln 2-3] … the geometric joint Jacobian [JjtT JjrT]T relates r˙C = R JJt(C, i)q˙J and ωi = R JJR(C, i)q˙J
EXAMINER NOTE: Angular velocity is calculated from the robot state information q (measured via sensors listed in table 1) and the geometric joint Jacobian.
an angular acceleration, and a linear acceleration of each link;
(Vorndamme - [p. 4756, col 1, Estimating Generalized Acceleration] In order to be able to determine as many contact wrenches and locations as possible, the external torques already isolated and identified by force/torque sensors are to be excluded from the observed generalized external forces ˆτε [21]. Therefore, we need to compensate for the dynamic and static forces generated by the mass/inertia attached to each sensor. For this compensation, the acceleration in Cartesian space ¨xD of its center of mass D is required. Assuming the sensor S to be mounted on link i, it may simply be calculated via
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EXAMINER NOTE: The above expression includes terms for linear acceleration and angular acceleration (r''_D and ω''_D, respectively). Estimation of q'' is discussed further in this section.
determining an inertial force and an inertial torque at the center of mass of a target link according to the motion state parameters and the inertial property parameters of each link;
(Vorndamme - [p.4756, col 2, Distal Sensor Case] … The body mass is mD and its inertia tensor ID. Newton’s second law yields
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It follows for the sensed external force
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Obviously, equation (13) shows that the sensor does not measure the pure external forces only, but also forces due to gravity and inertia.)
EXAMINER NOTE: The term mDr''D is the inertial force, calculated from the above known terms.
(Vorndamme - [p.4756, col 2, Distal Sensor Case] … (continued from above) To derive the external moment, Euler’s law of rigid body motion is applied to the center of gravity D of the body:
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This leads to the sensed external moment
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Equations (13) and (14) result in the sensed external wrench
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EXAMINER NOTE: Analogous to the above comment regarding equation 13, The term IDw'D in equation 16 is the inertial torque, calculated from the above known terms. Equation 16 is an expression of external wrench, which includes terms for both external force and external moment.
acquiring forces and torques between two ends of the target link and the corresponding joints respectively by the 6-DOF force and torque sensors;
EXAMINER NOTE: See Algorithm 1 and Equations 18, 19, and 27 (discussed in detail below). The compensation terms include forces and torques between the ends of each link and their respective joints in the chain measured by the sensors.
determining an external force applied to the target link according to the inertial force and the inertial torque at the center of mass of the target link, and the forces and the torques between the two ends of the target link and the corresponding joints.
(Vorndamme - [p. 4757, col 1, Intermediate Sensor Case] If the sensor is located within an intermediate link, the compensation wrenches for each body b, with center of mass Db, succeeding this sensor become
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and simply have to be summed up for compensation. Note that this operation explicitly corresponds to the Newton- Euler method for calculating multibody dynamics. Therefore, in this case, the estimated external wrench sensed in S
Becomes
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N(bs) denotes the set of all bodies succeeding link bs, that contains the sensor in the kinematic chain. For multiple sensors in a kinematic chain (e.g. in each joint), the compensation wrenches can be calculated recursively to avoid multiple calculations, see Algorithm 1. The code uses the set M(S), denoting all sensors T ∈ M(S) directly succeeding S. This means there is no further sensor between S and an element of M(S) in the kinematic chain connecting the two.
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EXAMINER NOTE: See Equations 18-19 and Algorithm 1 on page 4757, reproduced above. The computations are carried out by recursively analyzing the dynamics of the links and sensors. At the link level (bodies b), inertial forces are computed for a link and all links succeeding the current link. At the sensor level (T in M(S)), the function is called recursively, computing inertial forces for all links succeeding the current sensor. This process is repeated until all sensors have been accounted for, then the function moves to the next link in the chain and repeats all of the above until each link is accounted for. Carrying out the computations recursively in this manner ultimately results in a value of F_c which includes not only inertial terms for the link immediately forward of a given sensor (target link), but also force terms for every link to follow. In other words, F_c accounts for inertial forces and torques of a given link, as well as inertial forces, inertial torques, and external wrenches on every successive link. Therefore, using Equation 19 with the results of Algorithm 1, the external force (force component of wrench F_ext) is determined according to inertial force (force component of F_c) and inertial torque (torque component of F_c) of a target link, and forces and torques between the two ends of the target link and the corresponding joints (F_s and F_c).
(Vorndamme - [p.4758, col 2, Multiple Contacts] For the case of multiple contacts, above method may be used in combination with compensated force/torque sensing. Then, for each sensor, a contact in the kinematic chain following the sensor may be detected by applying steps 3 and 4 for the compensated (in the sense of (16) or (19)) wrenches ˆ Fext,S of the sensors. In case of more than one sensor and more than one contact in the kinematic chain, the wrenches originating from contacts already measured by sensors closer to the distal end of the chain have to be subtracted from the measured wrench. As a sensor sees all contact wrenches acting on subsequent sensors with an additional moment because of the change in lever of the force, in addition to the external wrenches exclusively seen by it, this leads to
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Considering the situation of Fig. 2 for example, two contacts can be detected at the right arm. One by sensor S3 and one by sensor S1, as long as one contact is behind S1 and the other between S3 and S1. As this is the case for Fext,2 and
Fext,5 these two wrenches may be estimated correctly.)
EXAMINER NOTE: Note that algorithm 1 is used in the context of a single sensor, and alone may not be useful for complex contact scenarios. Taking Algorithm 1 a step further, multiple contacts may be detected and isolated throughout the kinematic chain. Equation 27 determines and isolates the external force acting on a link 'k' by also considering the external wrenches sensed other sensors in the kinematic chain.
Claim 9
Vorndamme teaches
A robotic arm, comprising: a plurality of links connected in sequence; a plurality of joints, the links being connected by the joints;
EXAMINER NOTE: See Fig. 2. The robot comprises arms, the arms comprising links and joints connected in a sequence.
a plurality of six degrees of freedom (6-DOF) force and torque sensors being mounted on the joints at two ends of at least part of the links,
(Vorndamme - [p. 4754, col 2, para. 2 thru p.4755, col 1, ln 6] … In summary, the main contributions of this paper are … a new real-time method for acceleration estimation and load compensation in humanoid robots for force/torque sensors that are arbitrarily located in the kinematic robot chain …
[p.4757, col 1, ln 11-14] For multiple sensors in a kinematic chain (e.g. in each joint), the compensation wrenches can be calculated recursively to avoid
multiple calculations, see Algorithm 1.
[p.4756, col 2, para. 2] Equations (13) and (14) result in the sensed external wrench
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I3 denotes the three dimensional unit matrix, g the Cartesian gravity vector, rDS the vector from the center of mass of the inertia attached to the sensor to the sensor and 0 the zero matrix of suitable size.)
EXAMINER NOTE: Vorndamme states that the sensors are arbitrarily placed in the kinematic chain, and that in some cases they may be placed in each joint. While there is no explicit statement that the sensors act in six axes, it may be gleaned from equation 16 above that the measurements are taken in six axes (i.e. 3 axes of force and 3 axes of torques) based on the dimensionality of Is. Additionally, Figure 3 shows three coordinate axes (see annotated Fig. 3 below), each of which may correspond to a component of force and a component of torque (six components of a wrench)
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the 6-DOF force and torque sensors being configured to detect forces and torques applied to corresponding joints;
EXAMINER NOTE: See at least equations 13-16 and the discussion thereof on p.4756, col 2. It is clear that the force/torque sensors are used to detect forces and torques.
at least one memory storing computer program instructions; and
at least one processor, wherein when the computer program instructions are executed by the at least one processor, following steps are implemented:
(Vorndamme - The simulation is done on a standard Core i7-3770 PC and the algorithm is run as compiled Matlab functions.)
EXAMINER NOTE: The use of a PC and matlab indicates a memory and processor executing instructions.
The following remaining limitations of independent claim 9 are identical to limitations of claim 1 and are therefore rejected for the same reasons outlined above.
acquiring inertial property parameters of each link, the inertial property parameters comprising a mass, a center of mass, and a rotational inertia of each link;
determining motion state parameters of each link, the motion state parameters comprising an angular velocity, an angular acceleration, and a linear acceleration of each link;
determining an inertial force and an inertial torque at the center of mass of a target link according to the motion state parameters and the inertial property parameters of each link;
acquiring forces and torques between two ends of the target link and the corresponding joints respectively by the 6-DOF force and torque sensors; and
determining an external force applied to the target link according to the inertial force and the inertial torque at the center of mass of the target link, and the forces and the torques between the two ends of the target link and the corresponding joints.
Claim 17
Vorndamme teaches
A non-transitory computer-readable storage medium, on which computer program instruction are stored, wherein when the computer program instructions are executed by at least one processor, following steps are implemented:
(Vorndamme - The simulation is done on a standard Core i7-3770 PC and the algorithm is run as compiled Matlab functions.)
EXAMINER NOTE: The use of a PC and matlab indicates a memory and processor executing instructions.
The following remaining limitations of independent claim 17 are identical to limitations of claim 1 and are therefore rejected for the same reasons outlined above.
acquiring inertial property parameters of each link, the inertial property parameters comprising a mass, a center of mass, and a rotational inertia of each link;
determining motion state parameters of each link, the motion state parameters comprising an angular velocity, an angular acceleration, and a linear acceleration of each link;
determining an inertial force and an inertial torque at the center of mass of a target link according to the motion state parameters and the inertial property parameters of each link;
acquiring forces and torques between two ends of the target link and the corresponding joints respectively by the 6-DOF force and torque sensors; and
Claims 2, 10, and 18
Vorndamme teaches the limitations of claims 1, 9, and 17 as outlined above Vorndamme further teaches
wherein the determining the motion state parameters of each link comprises:
acquiring connection parameters of each joint and acquiring angular information of each joint,
the connection parameters representing a spatial position relationship of two adjacent links,
(Vorndamme - [p. 4755, col 1, Floating Base Robot Model] A rigid humanoid robot can be modeled by
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where qB = (rBT ϕTB)T and q = (qTB qJT)T denote the generalized coordinates of the floating base and the full robot. They consist of the Cartesian base position rB ∈ R3 Euler angle base orientation ϕB ∈ R3 and joint angles qJ ∈ RnJ . Base and joint entries are marked with index “B” and “J”, respectively.)
EXAMINER NOTE: Joint angles qJ (connection parameters) are part of the model. The joint angles are measured via various sensors supplied with the robot (see Table 1 [p. 4755, col 2])
and the angular information of each joint comprising
a joint angular position,
EXAMINER NOTE: Joint angles qJ are discussed above.
a joint angular velocity,
EXAMINER NOTE: See again Table 1 [p.4755, col 2]. Joint angular velocity q'J is measured.
and a joint angular acceleration; and
(Vorndamme - [p. 4756, col 1, Estimating Generalized Acceleration] …As one can see, the generalized acceleration ¨ q is needed to calculate the Cartesian acceleration. An estimate q^'' of q'' can be obtained from extending the disturbance observer (4). Using its inner state
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The estimated acceleration follows as
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EXAMINER NOTE: Vordamme estimates angular accelerations using the above model.
according to the inertial property parameters of each link, the connection parameters of each joint, and the angular information of each joint, determining the motion state parameters of each link using a robot dynamics principle.
(Vorndamme - [p.4755, col 2, ln 2-3] … the geometric joint Jacobian [JjtT JjrT]T relates r˙C = R JJt(C, i)q˙J and ωi = R JJR(C, i)q˙J
EXAMINER NOTE: Angular velocity is calculated from the robot state information q (measured via sensors listed in table 1) and the geometric joint Jacobian.
(Vorndamme - [p. 4756, col 1, Estimating Generalized Acceleration] In order to be able to determine as many contact wrenches and locations as possible, the external torques already isolated and identified by force/torque sensors are to be excluded from the observed generalized external forces ˆτε [21]. Therefore, we need to compensate for the dynamic and static forces generated by the mass/inertia attached to each sensor. For this compensation, the acceleration in Cartesian space ¨xD of its center of mass D is required. Assuming the sensor S to be mounted on link i, it may simply be calculated via
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EXAMINER NOTE: The above expression includes terms for linear acceleration and angular acceleration (r''_D and ω'_D, respectively). Estimation of q'' is discussed in the above citation. Note that the expression for estimated q'' in Equation 9 includes mass matrix M(q), which contains inertial properties.
Claims 4 and 12
Vorndamme teaches the limitations of claims 1 and 9 as outlined above. Vorndamme further teaches
wherein the determining the inertial force and the inertial torque at the center of mass of the target link according to the motion state parameters and the inertial property parameters of each link comprises:
determining the inertial force and the inertial torque at the center of mass of the target link according to the motion state parameters and the inertial property parameters of each link by using backward recursive equations of Recursive Newton-Euler equations.
(Vorndamme - [p. 4757, col 1, Intermediate Sensor Case] If the sensor is located within an intermediate link, the compensation wrenches for each body b, with center of mass Db, succeeding this sensor become
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and simply have to be summed up for compensation. Note that this operation explicitly corresponds to the Newton- Euler method for calculating multibody dynamics. Therefore, in this case, the estimated external wrench sensed in S
Becomes
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N(bs) denotes the set of all bodies succeeding link bs, that contains the sensor in the kinematic chain. For multiple sensors in a kinematic chain (e.g. in each joint), the compensation wrenches can be calculated recursively to avoid multiple calculations, see Algorithm 1. The code uses the set M(S), denoting all sensors T ∈ M(S) directly succeeding S. This means there is no further sensor between S and an element of M(S) in the kinematic chain connecting the two.
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EXAMINER NOTE: As discussed above with respect to claim 1, the compensation wrench Fc,b includes terms for inertial force and torque of the links.
Claims 5, 13, and 19
Voorndamme teaches the limitations of claims 4, 12, and 17 as outlined above. Voorndamme further teaches
wherein the determining the external force applied to the target link according to the inertial force and the inertial torque at the center of mass of the target link, and the forces and the torques between the two ends of the target link and the corresponding joints comprises:
determining a first difference between the inertial force at the center of mass of the target link and the forces between the two ends of the target link and the corresponding joints; and
(Vorndamme - [p.4756, col 2, Dynamic Load Compensation] Figure 3 depicts the free body diagram of a distal link containing a force/torque sensor S measuring a wrench FS. The left part belongs to the link connected to the base holding the sensor. The right part represents the body attached to the sensor generating gravitational and dynamic forces measured in the sensor. The body mass is mD and its inertia tensor ID. Newton’s second law yields
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It follows for the sensed external force
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EXAMINER NOTE: During the above derivation of the external wrench terms discussed at length in the rejection of claim 1, Vorndamme uses the example of a distal link to illustrate the application of Newton's second law. Vorndamme does not explicitly show an analogous derivation for the case of an intermediate link, but this case is accounted for later in Algorithm 1 Equations 18, 19, and 27 (discussed at length in the rejection of claim 1). Applicant's claim of a "difference" is due in part to the sign convention chosen arbitrarily for the application of Newton's law as evidenced by [0081]-[0084] of the substitute specification filed 11/27/2023. Vorndamme applies a different convention for the sign, but the end result is the same. If Vorndamme's sign convention were the same as applicant's, Equation 27 would result in the difference claimed by applicant (i.e. Fs would be negative)
determining a magnitude and a direction of the external force applied to the target link according to the first difference.
(Vorndamme - [p. 4758, col 1, ln 26-39] Step 3: For a single external wrench Fext acting at the contact location rC, the wrench Fi in Oi may be obtained with the adjoint matrix A(C,Oi) via
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Recalling the assumption of absence of external moments (mext = 0) this results in
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From (25), the line of action of the force can be derived. It is described by rA + λfi/||fi|| for λ ∈ R with
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f) Step 4: Due to the properties of the pseudo inverse and the rank deficit of skew symmetric matrices, rA is the point along the line of action of the force, which lies closest to the origin and therefore is not identical to rC in general. However, it is possible to calculate rC by intersecting the line of action of the force with the link geometry of the contact link.)
EXAMINER NOTE: The parameter rC above refers to contact location. In addition to the above citation, it should be noted that Vorndamme describes all variables in vector form. Vectors inherently include a magnitude and direction. It should be noted as well that for the case of multiple contacts described in the second column of the page 4758, the wrench Fext in equation 24 would be Fext,k calculated in equation 27, which accounts for the difference between inertial force and the forces at the ends of the link.
(Vorndamme - [p.4758, col 2, Multiple Contacts] … In case of more than one sensor and more than one contact in the kinematic chain, the wrenches originating from contacts already measured by sensors closer to the distal end of the chain have to be subtracted from the measured wrench. As a sensor sees all contact wrenches acting on subsequent sensors with an additional moment because of the change in lever of the
force, in addition to the external wrenches exclusively seen by it, this leads to
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Claims 6, 14 and 20
Voorndamme teaches the limitations of claims 5, 13, and 19 as outlined above. Voorndamme further teaches
determining a net torque of the target link at a reference point
according to a second difference between the torques between the two ends of the target link and the corresponding joints and the inertial torque of the target link at the center of mass;
(Vorndamme - [p.4758, col 2, Multiple Contacts] … In case of more than one sensor and more than one contact in the kinematic chain, the wrenches originating from contacts already measured by sensors closer to the distal end of the chain have to be subtracted from the measured wrench. As a sensor sees all contact wrenches acting on subsequent sensors with an additional moment because of the change in lever of the
force, in addition to the external wrenches exclusively seen by it, this leads to
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)
EXAMINER NOTE: Referring again to the discussion of equation 27 in the rejection of claim 5 above, the wrench Fext accounts for the difference between the torques between the ends of the target link and the joints, as it includes moment components as well as force components. Even with the assumption of zero external moments, the net torque would still exist as a function of inertial torques from links forward of the sensor and the reaction torque on the sensor, as well as the torques resulting from the contact forces. Each of these terms is included in equation 27 when the recursive Algorithm 1 is carried out and applied to equation 27.
And determining a location of the external force applied to the target link relative to the reference point according to the net torque of the target link at the reference point, and the magnitude and the direction of the external force applied to the target link.
(Vorndamme - [p. 4758, col 1, ln 26-39] Step 3: For a single external wrench Fext acting at the contact location rC, the wrench Fi in Oi may be obtained with the adjoint matrix A(C,Oi) via
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Recalling the assumption of absence of external moments (mext = 0) this results in
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From (25), the line of action of the force can be derived. It is described by rA + λfi/||fi|| for λ ∈ R with
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f) Step 4: Due to the properties of the pseudo inverse and the rank deficit of skew symmetric matrices, rA is the point along the line of action of the force, which lies closest to the origin and therefore is not identical to rC in general. However, it is possible to calculate rC by intersecting the line of action of the force with the link geometry of the contact link.)
EXAMINER NOTE: The parameter rC above refers to contact location. In addition to the above citation, it should be noted that Vorndamme describes all variables in vector form. Vectors inherently include a magnitude and direction. As discussed above, for the case of multiple contacts described in the second column of the page 4758, the wrench Fext in equation 24 would be Fext,k calculated in equation 27, which accounts for the difference between inertial torque and the torques at the ends of the link. Essentially, the differences are accounted for in the term mi after application of equation 27. The magnitude and direction of the force are accounted for in the calculation of the line of action using rA ( fi / ||fi|| is the unit vector of the force, indicating a direction). With rA being a point along the line of action of the force, rA can be utilized to determine the contact location.
Claims 7 and 15
Voorndamme teaches the limitations of claims 6 and 14 as outlined above. Voorndamme further teaches
wherein before determining the location of the external force applied to the target link relative to the reference point according to the net torque of the target link at the reference point, and the magnitude and the direction of the external force applied to the target link, the method further comprises:
determining whether the magnitude of the external force is greater than a predetermined first threshold value, and determining whether a value of the net torque is greater than a predetermined second threshold value;
determining that there is no external force applied to the target link if the magnitude of the external force is less than the first threshold value; and
(Vorndamme - [p.4757, col 2, Collision Detection] Collision detection is simply done via thresholding the generalized forces and estimated external wrenches)
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EXAMINER NOTE: The thresholding is carried out element-wise, meaning that both forces and torques are compared to respective thresholds.
determining that the external force applied to the target link is located at the reference point if the magnitude of the external force is greater than or equal to the first threshold value and the value of the net torque is less than the second threshold value.
EXAMINER NOTE: Once the thresholding is carried out to determine a collision, the external wrenches are determined and located in the manner discussed on page 4758 discussed at length in the above rejections.
Claim Rejections - 35 USC § 103
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.
Claim(s) 3 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Voorndamme as applied to claims 1 and 9 above, and further in view of Rabindran (US 20190143513 A1).
Claims 3 and 11
Voorndamme teaches the liitations of claims 1 and 9 as outlined above. Voorndamme may not explicitly teach the following limitations in combination, but Rabindran teaches
wherein an inertial measurement unit is mounted on each of the links for measuring the angular velocity, the angular acceleration, and the linear acceleration of a corresponding link,
(Rabindran - [0057] In the example of FIG. 2A, a link sensor system 204 is attached to each of the links L1, L2, L3, and L4 of a kinematic chain. In various examples, the link sensor system 204 may be located at any portion of its corresponding link (L1, L2, L3, or L4). The link sensor system 204 may include one or more sensors including, for example, an inertial measurement unit (IMU), …In some examples, the link sensor system 204 may include an accelerometer configured to measure the three dimensional linear acceleration of the corresponding link and a gyroscope configured to measure the three dimensional angular velocity of the corresponding link.
the determining the motion state parameters of each link comprises:
obtaining the motion state parameters of each link from the inertial measurement units.
(Rabindran - [0091] The method 550 may then proceed to operation 560, where the recursive kinematics estimator 440 may compute an estimation for angular link acceleration ω'i+1, for link Li+1 based on link measurement data ωi, ωi+1, x''i, x''i+1 and estimated link data ω'i according to equations (7) as follows: …)
EXAMINER NOTE: Angular acceleration of the link is determined from IMU measurements.
(Rabindran - [0092] The method 550 may then proceed to operation 562, where the recursive kinematics estimator 440 computes joint acceleration θ''n for joint J.sub.i+1 using estimated link data ω'i and ω'i+1, and link measurement data ωi as follows: …)
EXAMINER NOTE: The angular acceleration may be used to determine joint parameters
(Rabindran - [0097] Referring to FIGS. 4 and 6A, in some embodiments, a fused estimator 441 of the joint state estimator 430 (e.g., joint state estimator 430 of FIG. 4) may generate joint acceleration estimates based on robustness requirements and/or link data (e.g., link angular velocity data, link acceleration data) availability. In an example, each link sensor system 204 may include a link angular velocity sensor 602 (e.g. a gyroscope) configured to measure the angular velocity of a link, and/or a link acceleration sensor 604 (e.g., an accelerometer) configured to measure link acceleration. In an example, a first joint acceleration estimate may be generated only based on link angular velocity data ω.sub.i and ω.sub.i+1 without using link acceleration data {umlaut over (x)}.sub.i and {umlaut over (x)}.sub.i+1. In one example, the first acceleration estimate may be used when the link acceleration sensor 604 is unavailable and the estimate can be determined only based on the measurements of a link angular velocity sensor 602. In another example, a fused joint acceleration estimate may be generated using the first joint acceleration estimate and second joint acceleration estimate computed based link angular velocity data, link acceleration data, manipulator dynamic model, and/or kinematics of the manipulator. Such fusion may improve the robustness and signal-to-noise ratio (SNR) of the joint acceleration estimate.)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify Vorndamme with Rabindran's suggestion to incorporate IMU sensors on each link in the kinematic chain in order to improve robustness of the joint acceleration estimates. Note that rather than using measurements, Vorndamme utilizes an analytical estimate of q'', the error of which is tracked (see page 4756, col 1, equations 9-11). Rabindran's use of accelerometer and gyroscope sensors provides an additional way to track the state of the robot. Further, Rabindran suggests that redundant sensors may be used when primary sensors are unavailable. Vorndamme's system estimates the robot state using encoders, but incorporation of Rabindran's sensors would allow for additional ways to calculate the state of the robot joints.
Claim(s) 8 and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Voorndamme as applied to claims 7 and 15 above, and further in view of Anonymous (Rigid Bodies; Equivalent Systems of forces) and Owen (Vectors, Matrices, and Linear Algebra)
Claims 8 and 16
Voorndamme teaches the limitations of claims 7 and 15 as outlined above. Voorndamme alone may not explicitly teach the following limitations in combination.
determining the location of the external force applied to the target link relative to the reference point according to following equations if the magnitude of the external force is greater than or equal to the first threshold value and the value of the net torque is greater than the second threshold:
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wherein rmag is a shortest distance from the reference point to an action line of the external force applied to the target link,
rvec is a shortest vector from the reference point to the action line of the external force applied to the target link,
M is the net torque, and F reflects the magnitude and the direction of the external force applied to the target link.
However, the claimed expression of rmag and rvec and their use is a routine, well-understood calculation, as evidenced by Anonymous and Owen.
Anonymous provides a basic introduction to the concept of expressing forces and moments in terms of vectors. Anonymous outlines the use of the cross product to define a moment in terms of force and a perpendicular distance from an arbitrary point O on page 2:
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Anonymous shows that a moment is defined as the product of a Force F and a perpendicular distance d. The variable d is analogous to Applicant's claimed rmag. Rearranging the above expression to solve for the distance yields d = M/F, which is analogous the expression rmag = ||M|| / ||F|| claimed by applicant. It should be noted that Vorndamme has provided the calculation of F and M, and also a method for calculating the point of contact relative to a reference point, but Vorndamme differs in the method of calculating the contact point.
As for the expression of rvec:
Note that the cross product of two vectors yields a third vector which lies along a direction perpendicular to the vectors in the cross product
(Anonymous - [p.3, Vector Cross Product] Vector product of two vectors P and Q is defined as the vector V which satisfies the following conditions:
Line of action of V is perpendicular to plane containing P and Q
…)
Then, the product M x F in the numerator of the expression for rvec yields a vector perpendicular to both the Moment and the Force (i.e. along the same direction as d in the figure above). The denominator of rvec is the magnitude of this vector. Owen states
(Owen - [p.2, para. 2-4] The magnitude of a vector is a scalar value – a number representing the length of the vector independent of the direction. …
To complement the magnitude, which represents the length independent of direction, one might wish for a way of representing the direction of a vector independent of its length. For this purpose, we use “unit vectors,” which are quite simply vectors with a magnitude of 1. A unit vector is denoted by a small “carrot” or “hat” above the symbol. For example, a^ represents the unit vector associated with the vector a. To calculate the unit vector associated with a particular vector, we take the original vector and divide it by its magnitude. In mathematical terms, this process is written as
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Definition: A unit vector is a vector of magnitude 1. Unit vectors can be used to express the direction of a vector independent of its magnitude.)
Then, the fraction in the expression for rvec represents a vector with a length of unity in the direction of the moment arm. As established above, rmag represents the magnitude of the moment arm. Therefore, the expression for rvec is simply an expression for the magnitude and direction of the moment arm originating at a reference point.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to substitute Vorndamme's method of finding the contact point with the above expressions. The expressions are elementary derivations using generic vector manipulations which are taught at an undergraduate level, and therefore within the ordinary capabilities of anyone of ordinary skill in the art. Due to the definition of a moment (or torque) as known by those skilled in the art (and as set forth by Anonymous), the application of the above expressions would yield the predictable result of obtaining the location of an external force on an arbitrary rigid body relative to a reference point.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. The following documents particularly pertain to the use of force sensors and methods of detecting external forces on robots:
G. Buondonno and A. De Luca, "Combining real and virtual sensors for measuring interaction forces and moments acting on a robot," 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Daejeon, Korea (South), 2016,
JP 2020037172 A
US-20110160906-A1
US 20210060793 A1
DE 102021113636 B3
US-20220416701-A1
THIS ACTION IS MADE FINAL. 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.
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/JAMES MILLER WATTS III/Examiner, Art Unit 3657
/ADAM R MOTT/Supervisory Patent Examiner, Art Unit 3657