Manual teaching process in a robot manipulator with force/torque specification

Abstract

A robot manipulator including limbs moveable via bearings controlled by actuators; sensors to capture a bearing position and a bearing torque/bearing force; a first sensor to capture a force screw W; a housing downstream of the first sensor; a second sensor to capture a user force applied to the housing and/or a user torque; a computing unit to determine, using a dynamics model of the robot manipulator and based on particular bearing torque/bearing force, the force screw W, and the user force and/or the user torque, a first force and/or a first torque to shift the limbs and a second force and/or a second torque to apply to an external object via an effector, wherein the dynamics model includes at least gravitational forces and inertial forces based on the bearing position; and a storage unit to store the first and/or the second force, and/or the first and/or the second torque.

Claims

1. A robot manipulator to determine and store a desired force and/or a desired torque from a manual teaching process, the robot manipulator comprising: a number N of robot limbs GL.sub.n, where n=1, . . . , N and N>2, wherein a robot limb GL.sub.n=1 is connected to a robot base, and a robot limb GL.sub.N is a distal end member of the robot manipulator and is designed to receive an end effector, and wherein the robot limbs GL.sub.n are movable in pairs with respect to one another via bearings controlled by actuators, and a particular one of the bearings has a rotational and/or translational degree of freedom; bearing sensors arranged on the bearings and are designed to capture a bearing position and a bearing torque/bearing force, in each case in a direction of a particular degree of freedom of a particular one of the bearings; a first sensor arranged on one of the robot limbs GL.sub.N-a, where aε{0, 1, 2}, and wherein the first sensor is designed to capture a force screw W; an operating housing arranged on a robot limb GL.sub.N-b, where b≥a; a second sensor arranged on the operating housing and is used to capture a user torque applied to the operating housing; and/or a user force; a computing unit connected to the bearing sensors, the first sensor, and the second sensor, the computing unit designed to determine, using a dynamics model of the robot manipulator and based on a particular bearing torque/bearing force, the force screw W, and the user torque and/or the user force, a first desired force and/or a first desired torque to shift the robot limbs GL.sub.n, and a second desired force and/or a second desired torque to apply to an external object via the end effector, wherein the dynamics model includes at least gravitational forces and inertial forces based on the bearing position, and a storage unit to store the first and/or the second desired force, and/or the first and/or the second desired torque.

2. The robot manipulator according to claim 1, wherein the force screw W has forces and torques on and about axes that are orthogonal to one another in pairs.

3. The robot manipulator according to claim 2, wherein the force screw W has forces and torques on and about three axes that are orthogonal to one another in pairs.

4. The robot manipulator according to claim 1, wherein the second sensor is used to capture a user torque applied to the operating housing.

5. The robot manipulator according to claim 1, wherein robot limbs GL.sub.N-a-1 to GL.sub.N are movable relative to one another in/about a number c of movement axes, and wherein the second sensor is designed to capture only user forces/user torques in/about axes consisting of a linear combination of the c movement axes.

6. The robot manipulator according to claim 1, wherein robot limbs GL.sub.N-a-1 to GL.sub.N are rotatably movable relative to one another about a number c of axes of rotation, and wherein the second sensor is designed to capture only user torques about axes consisting of a linear combination of the c axes of rotation.

7. The robot manipulator according to claim 1, wherein robot limbs GL.sub.N-a-1 to GL.sub.N are rotatably movable relative to one another about a number c of axes of rotation, and wherein the second sensor is designed to capture only user torques about axes in parallel with at least one of the c axes of rotation.

8. The robot manipulator claim 1, wherein the bearings are in each case articulations, and/or pivot bearings, and/or linear bearings.

9. The robot manipulator according to claim 1, wherein the following applies: b=a or b=a+1.

10. A method of determining and storing a desired force and/or a desired torque from a manual teaching process on a robot manipulator, wherein the robot manipulator comprises a number N of robot limbs GL.sub.n, where n=1, . . . , N and N>2, wherein a robot limb GL.sub.n=1 is connected to a robot base, and a robot limb GL.sub.N is a distal end member of the robot manipulator and is designed to receive an end effector, and wherein the robot limbs GL.sub.n are movable in pairs with respect to one another via bearings controlled by actuators, and a particular one of the bearings has a rotational and/or translational degree of freedom, the method comprising: capturing a bearing position and a bearing torque/bearing force, in each case in a direction of a particular degree of freedom of a particular one of the bearings, via bearing sensors arranged on the bearings; capturing a force screw W via a first sensor arranged on one of the robot limbs GL.sub.N-a, where aε{0, 1, 2}; capturing, via a second sensor, a user force and/or a user torque applied to an operating housing, wherein the operating housing arranged on a robot limb GL.sub.N-b, where b≥a; using a dynamics model of the robot manipulator and based on a particular bearing torque/bearing force, the force screw W, and the user force and/or the user torque: determining, using a computing unit connected to the bearing sensors, the first sensor, and the second sensor, a first desired force and/or a first desired torque to shift the robot limbs GL.sub.n, and a second desired force and/or a second desired torque to apply to an external object via the end effector, wherein the dynamics model includes at least gravitational forces and inertial forces based on the bearing position; and storing, in a storage unit, the first and/or the second desired force, and/or the first and/or the second desired torque.

11. The method according to claim 10, wherein the force screw W has forces and torques on and about axes that are orthogonal to one another in pairs.

12. The method according to claim 11, wherein the force screw W has forces and torques on and about three axes that are orthogonal to one another in pairs.

13. The method according to claim 10, wherein the second sensor is used to capture a user torque applied to the operating housing.

14. The method according to claim 10, wherein robot limbs GL.sub.N-a-1 to GL.sub.N are movable relative to one another in/about a number c of movement axes, the method further comprising capturing via the second sensor only user forces/user torques in/about axes consisting of a linear combination of the c movement axes.

15. The method according to claim 10, wherein robot limbs GL.sub.N-a-1 to GL.sub.N are rotatably movable relative to one another about a number c of axes of rotation, the method further comprising capturing via the second sensor only user torques about axes consisting of a linear combination of the c axes of rotation.

16. The method according to claim 10, wherein robot limbs GL.sub.N-a-1 to GL.sub.N are rotatably movable relative to one another about a number c of axes of rotation, the method further comprising capturing via the second sensor only user torques about axes in parallel with at least one of the c axes of rotation.

17. The method according to claim 10, wherein the bearings are in each case articulations, and/or pivot bearings, and/or linear bearings.

18. The method according to claim 10, wherein the following applies: b=a or b=a+1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 shows a robot manipulator including a computing unit to determine a first and/or a second desired force, and a first and/or a second desired torque from a manual teaching process on a robot manipulator according to an embodiment of the invention; and

(3) FIG. 2 shows a method of determining and storing a first and/or a second desired force, and/or a first and/or a second desired torque from a manual teaching process on a robot manipulator according to a further embodiment of the invention.

(4) The figures in the drawings are schematic and not to scale.

DETAILED DESCRIPTION

(5) FIG. 1 shows a robot manipulator 1, including a number N of robot limbs GL.sub.n, where n=1, . . . , N and N>2, a robot limb GL.sub.n=1 being connected to a robot base 3, and a robot limb GL.sub.N being a distal end member of the robot manipulator 1 and being designed to receive an end effector 5, and the robot limbs GL.sub.n being movable in pairs with respect to one another via bearings 7 which can be controlled by actuators, and a particular one of the bearings 7 having a rotational degree of freedom, the robot manipulator further including bearing sensors 9 which are arranged on the bearings 7 and are designed to capture a bearing position and a bearing torque, in each case in a direction of a particular degree of freedom of a particular one of the bearings 7, further including a first sensor 11 which is arranged on robot limbs GL.sub.N-a, where aε{1, 2}, wherein, in the case shown, a=1, and designed to capture a force screw W, the force screw W having forces on and torques about axes that are orthogonal to one another in pairs. Furthermore, the force screw W has forces and torques which are based on and about three axes of a Cartesian coordinate system that are orthogonal to one another in pairs. In the case shown, the following applies: a E {1}, which can also be written as “a=1,” since the amount from which a originates is restricted to a single element “one.”

(6) Furthermore, the robot manipulator 1 includes an operating housing 13 which is arranged on a robot limb GL.sub.N-b, where b≥a, and a second sensor 15 which is arranged on the operating housing 13 and is used to capture a user torque applied to the operating housing 13, and a computing unit 17 which is connected to the bearing sensors 9 and to the first sensor 11 and to the second sensor 15, and which is designed to determine, using a dynamics model of the robot manipulator 1 and based on the particular bearing torque, the force screw W, and the user torque, a first desired force and/or a first desired torque to shift the robot limbs GL.sub.n, and a second desired torque to apply to an external object via the end effector 5, wherein the dynamics model includes at least gravitational forces and inertial forces based on the particular bearing position. Finally, the robot manipulator includes a storage unit 19 which is designed to store the first and the second desired torque. The robot limbs GL.sub.N-a-1 to GL.sub.N, i.e., the robot limbs GL.sub.n=2 to GL.sub.n=4, are rotatably movable relative to one another about a number c=2 of movement axes (through the joint L.sub.k=3 and joint L.sub.k=4), the second sensor 15 being designed to capture only user torques about axes consisting of a linear combination of the c=2 movement axes. In the present case, only one of the torques about the c=2 movement axes is captured, in that, in a linear combination, a factor for the degree of freedom allowed by the joint L.sub.k=4 is set to zero, and the degree of freedom allowed by the joint L.sub.k=3 is taken into account by a factor equal to one, and a user torque is captured therein, as a result of which the torque is captured in a redundant manner by the first sensor and the second sensor. In principle, and irrespective of the method according to the invention, the dynamics of a robot manipulator (1) can be modelled by the following equation:
M(q){umlaut over (q)}+C(q,q){dot over (q)}+G(q)=T.sub.tot,  (1)

(7) where, in equation (1), the following applies:

(8) q: is a vector of generalized coordinates;

(9) {dot over (q)}: is a first temporal derivation of the vector of generalized coordinates;

(10) {umlaut over (q)}: is a second temporal derivation of the vector of generalized coordinates;

(11) M: is a mass matrix of the robot manipulator 1;

(12) C: is a matrix having Coriolis terms;

(13) G: is a gravitational influence on the robot manipulator 1;

(14) T.sub.tot: is a vector of further forces and torques acting on the robot manipulator 1, in particular including drive torques (or drive forces in the case of translationally moved linear motors), and external forces and torques, which arise in particular from contacts of the robot manipulator 1 with an external object.

(15) Owing to the arrangement, in FIG. 1, of the first sensor 11, second sensor 15, and the bearing sensors 9, the dynamics from equation (1) are transcribed in the following manner:
M(q){umlaut over (q)}+C(q,q)q+G(q)=[τ.sub.1, . . . ,τ.sub.K-2,τ.sub.UI+W[5],W[6]].sup.T+J.sub.EE.sup.T(q)W+Σ.sup.PJ.sub.P.sup.T(q)W.sub.(P,ext),  (2)

(16) the symbols in equations (2) and (1) corresponding to one another; furthermore, in equation (2):

(17) τ.sub.i to τ.sub.[K-2]: being in each case a scalar of a particular bearing torque/bearing force in a particular one of the bearings 7 L.sub.K, K representing the number of L.sub.k bearings 7, where k=1, . . . , K and K=N, and in particular the following applying: The robot limb GL.sub.n=1 is connected to the robot base 3 by the bearing 7 L.sub.k≤1, and, at the opposite end thereof, to the bearing 7 L.sub.k=2 having the robot limb GL.sub.n=2 adjacent thereto, such that ultimately the bearing 7 L.sub.k=4=L.sub.K is arranged on the robot limb GL.sub.N=4;

(18) τ.sub.[UI]: being a user torque applied to the operating housing 13, as captured by the second sensor 15, wherein the captured user torque is in parallel with the axis of rotation from the rotational degree of freedom of the robot limb GL.sub.N-1=GL.sub.n=3, and is therefore entered into line N−1 of the vector [τ.sub.1, . . . , τ.sub.K-2, T.sub.UI+W[5], W[6]].sup.T (the penultimate entry);

(19) W: The force screw W, W[5], and W[6] being components of the vector of forces and torques recorded by the first sensor 11. In the force screw W, the recorded forces are listed in the first three components, and the recorded torques are listed in the further three components. In the case of FIG. 1, W[6], as the torque about the axis of the rotational degree of freedom of the robot limb GL.sub.4, does not contribute to the redundant measurement, and therefore forms only the last entry of [τ.sub.1, . . . , τ.sub.K-2, τ.sub.UI+W[5], W[6]].sup.T

(20) J.sub.EE: A Jacobian matrix for describing the force screw W captured on the robot limbs GL.sub.N-a on the bearing 7 L.sub.k, in particular on a particular bearing torque/bearing force;

(21) J.sub.P: A Jacobian matrix for describing the force screw W.sub.P,ext desired at point P on the bearing 7 L.sub.K, in particular on a particular bearing torque/bearing force;

(22) (⋅).sup.T: In this case, the superscript “T” specifies, on each sign, the transposed operator which describes a row vector in a column vector and vice versa, and transposes a matrix accordingly, such as the particular Jacobian matrix. Equation (2) thus specifies the dynamics model of the robot manipulator 11. Thus, by solving the equation (2) according to Σ.sup.P J.sub.P.sup.T(q)W.sub.(P,ext), a first desired force and/or a first desired torque to shift the robot limbs GL.sub.n, and a second desired force and/or a second desired torque to apply to an external object via the end effector 5 are determined based on the particular bearing torque/bearing force, the force screw W, and the user force and/or the user torque.

(23) FIG. 2 shows a method of determining and storing a desired force and/or a desired torque from a manual teaching process on a robot manipulator 1, the robot manipulator 1 including a number N of robot limbs GL.sub.n, where n=1, . . . , N and N>2, a robot limb GL.sub.n=1 being connected to a robot base 3, and a robot limb GL.sub.N being a distal end member of the robot manipulator 1 and being designed to receive an end effector 5, and the robot limbs GL.sub.n being movable in pairs with respect to one another via bearings 7 which can be controlled by actuators, and a particular one of the bearings 7 having a rotational and/or translational degree of freedom, the method including: capturing (S1) a bearing position and a bearing torque/bearing force, in each case in a direction of a particular degree of freedom of a particular one of the bearings 7, via bearing sensors 9 arranged on the bearings 7; capturing (S2) a force screw W via a first sensor 11 arranged on one of the robot limbs GL.sub.N-a, where aε{0, 1, 2}; capturing (S3), via a second sensor 15, a user force and/or a user torque applied to an operating housing 13, the operating housing 13 being arranged on a robot limb GL.sub.N-b, where b≥a; using a dynamics model of the robot manipulator 1 and based on a particular bearing torque/bearing force, the force screw W, and the user force and/or the user torque: determining (S4), using a computing unit 17 connected to the bearing sensors 9, the first sensor 11, and the second sensor 15, a first desired force and/or a first desired torque to shift the robot limbs GL.sub.n, and a second desired force and/or a second desired torque to apply to an external object via the end effector 5, wherein the dynamics model includes at least gravitational forces and inertial forces based on the particular bearing position; and storing (S5), in a storage unit 19, the first and/or the second desired force, and/or the first and/or the second desired torque.

(24) Although the invention has been illustrated and explained in greater detail by way of preferred embodiments, the invention is not limited by the disclosed examples, and a person skilled in the art can derive other variations herefrom, without departing from the scope of protection of the invention. It is therefore clear that there is a plurality of possible variants. It is also clear that embodiments cited by way of example really only represent examples which are not to be interpreted, in any way, as any kind of limitation of the scope of protection, the possible applications, or the configuration, of the invention. Instead, the above description and the description of the figures allow a person skilled in the art to specifically implement the embodiments given by way of example, a person skilled in the art being able, with knowledge of the disclosed concept of the invention, to make various amendments, for example with respect to the function or the arrangement of individual elements cited in an embodiment given by way of example, without departing from the scope of protection that is defined by the claims and the legal equivalent thereof, such as further explanations in the description.

LIST OF REFERENCE SIGNS

(25) 1 robot manipulator 3 robot base 5 end effector 7 bearing 9 bearing sensors 11 first sensor 13 operating housing 15 second sensor 17 computing unit 19 storage unit S1 capture S2 capture S3 capture S4 determine S5 store