Device and Method for Performing Open-Loop and Closed-Loop to Control of a Robot Manipulator

Abstract

The invention relates to a device and method for performing open-loop and closed-loop control of a robot manipulator which is driven by a number M of actuators ACT.sub.m and has an end effector. The invention comprises a first unit which registers and/or makes available an external force winder {right arrow over (F)}.sub.ext(t)={{right arrow over (f)}.sub.ext(t),{right arrow over (m)}.sub.ext(t)} acting on the end effector, a regulator which is connected to the first unit and to the actuators ACT.sub.m and which comprises a first regulator R1, which is a force regulator, and a second regulator R2 which is connected thereto and which is an impedance regulator, an admittance regulator, a position regulator or a cruise controller, wherein the regulator determines manipulated variables u.sub.m(t) with which the actuators ACT.sub.m can be actuated in such way that when contact occurs with the surface of an object, the end effector acts on said object with a predefined force winder {right arrow over (F)}.sub.D(t)={{right arrow over (f)}.sub.D(t),{right arrow over (m)}.sub.D(t)}; where u.sub.m(t)=u.sub.m,R1(t)+u.sub.m,R2(t), wherein the first regulator R1 is embodied and configured in such a way that the manipulated variable u.sub.m,R1(t) is determined as a product of a manipulated variable u.sub.m,R1(t)* and a function S(v(t)) or as a function S*(v(t), u.sub.m,R1(t)*), where: u.sub.m,R1(t)=S(v(t)) u.sub.m,R1(t)* or u.sub.m,R1(t)=S*(v*(t), u.sub.m,R1(t)*); v(t)=v({right arrow over (F)}.sub.D(t), {right arrow over (R)}(t)); v[v.sub.a, v.sub.e], v*(t)=v*({right arrow over (F)}.sub.D(t), {right arrow over (R)}(t))=[v.sub.1*({right arrow over (F)}.sub.D(t), {right arrow over (R)}(t)), . . . , v.sub.Q*({right arrow over (F)}.sub.D(t), {right arrow over (R)}(t))].

Claims

1. A device for performing open-loop and closed loop control of a robot manipulator having an end effector, which is driven by a number M of actuators ACT.sub.m, where m=1, 2, . . . , M, comprising: a first unit, which registers and/or makes available an external force winder {right arrow over (F)}.sub.ext(t)={{right arrow over (f)}.sub.ext(t),{right arrow over (m)}.sub.ext(t)} acting on the end effector, where: {right arrow over (f)}.sub.ext(t):=external force acting on the end effector; {right arrow over (m)}.sub.ext(t):=external torque acting on the effector; a regulator R1 connected with the first unit and the actuators ACT.sub.m, which comprises a first regulator R1, which is a force regulator, and a second regulator R2 connected therewith, which is an impedance regulator, an admittance regulator, a position regulator or a cruise control, wherein the regulator determines manipulated variables u.sub.m(t), by means of which the actuators ACT.sub.m can be actuated in such way that when contact occurs with the surface of an object, the end effector acts on said object with a predefined force winder {right arrow over (F)}.sub.D(t)={right arrow over (f)}.sub.D(t),{right arrow over (m)}.sub.D(t)}; wherein,
u.sub.m(t)=u.sub.m,R1(t)+u.sub.m,R2(t),(1) where: {right arrow over (f)}.sub.D(t):=predefined force; {right arrow over (m)}.sub.D(t):=predefined torque, u.sub.m,R1(t):=ratio of manipulated variables of the first regulator R1, and u.sub.m,R2(t):=ratio of manipulated variables of the second regulator R2 wherein the first regulator R1 is embodied and configured in such way that the manipulated variable u.sub.m,R1(t) is determined as product of a manipulated variable u.sub.m,R1(t)* and a function S(v(t)) or as a Q-dimensional function S*(v*(t), u.sub.m,R1(t)*), where:
u.sub.m,R1(t)=S(v(t)).Math.u.sub.m,R1(t)*(2a)
u.sub.m,R1(t)=S*(v*(t),u.sub.m,R1(t)*)(2b)
v(t)=v({right arrow over (F)}.sub.D(t),{right arrow over (R)}(t))(3a)
v*(t)=v*({right arrow over (F)}.sub.D(t),{right arrow over (R)}(t))=[v.sub.1*({right arrow over (F)}.sub.D(t),{right arrow over (R)}(t)), . . . ,v.sub.Q*({right arrow over (F)}.sub.D(t),{right arrow over (R)}(t))]v*(t)=[v.sub.1*(t),v.sub.2*(t), . . . ,V.sub.Q*(t)](3b)
v(t)[v.sub.a,v.sub.e](4a)
v.sub.1*(t)[v.sub.1a,v.sub.1e],v.sub.2*(t)[v.sub.2a,v.sub.2e], . . . ,v.sub.Q*(t)[v.sub.Qa,v.sub.Qe](4b) where: u.sub.m,R1*(t):=a manipulated variable determined by the first regulator R1 to generate the predefined force winder {right arrow over (F)}.sub.D(t), {right arrow over (R)}(t):=a provided negative deviation of the regulator, S(v(t)):=a monotonically decreasing function of v(t), which depends on {right arrow over (F)}.sub.D(t) and {right arrow over (R)}(t), S*(v*(t), u.sub.m,R1(t)*):=a function, where the influence of u.sub.m,R1(t)* is monotonically decreasing, [v.sub.a, v.sub.e]:=a predefined definition area of the variable v(t) [v.sub.1a, v.sub.1b,], . . . :=component-wise predefined definition area of the Q-dimensional variable v*(t).

2. The device according to claim 1, wherein, in case that the object is elastic and its surface is flexible, the regulator takes into consideration predefined elasticity properties of the object when determining the manipulated variables n u.sub.m(t).

3. The device according to claim 1, wherein a second unit is present, which serves as energy storage for passivation of the regulator, and which stores energy T1 coming from regulator according to predefined energy storage dynamics, and delivers energy T2 to the regulator, wherein the second unit and the regulator form a closed-loop, and an initialization of the second unit with an energy T0 depends on a determined or predefined expenditure of energy E.sub.Expenditure to implement a current task of the robot manipulator.

4. The device according to claim 3, wherein the stored energy E is a virtual or a physical energy.

5. The device according to claim 3, wherein an upper energy limit G1 is defined, and the second unit is embodied and configured such that EG1 is always true for the energy E stored in the second unit.

6. The device according to claim 5, wherein a lower energy limit G2 is defined as: 0<G2<G1, and the second unit is embodied such that, if: G2<EG1 is true for the energy E stored in the second energy unit, the second unit is coupled to the regulator, and EG2 is true for the energy E stored in the second energy unit, the second unit is uncoupled from the regulator.

7. The device according to claim 1, wherein the first unit has as sensor system to register the external force winder {right arrow over (F)}.sub.ext(t)={{right arrow over (f)}.sub.ext(t),{right arrow over (m)}.sub.ext(t)} and/or an estimator to estimate the external force winder {right arrow over (F)}.sub.ext(t)={{right arrow over (f)}.sub.ext(t),{right arrow over (m)}.sub.ext(t)}.

8. A robot having a robot manipulator driven by a number of M actuators ACT.sub.m having an end effector, which has a device according to claim 1, where m=1, 2, . . . , M.

9. A method for open-loop and closed-loop control of a robot manipulator driven by a number of M actuators ACT.sub.m, having an end effector, where m=1, 2, . . . , M, with the following steps: registering and/or making available an external force winder {right arrow over (F)}.sub.ext(t)={{right arrow over (f)}.sub.ext(t),{right arrow over (m)}.sub.ext(t)} acting on the end effector, where: {right arrow over (f)}.sub.ext(t):=external force acting on the end effector; {right arrow over (m)}.sub.ext(t):=external torque acting on the end effector; by means of a regulator, which comprises a first regulator R1, which is a force regulator, and a second regulator R2 connected therewith, which is an impedance regulator, an admittance regulator, a position regulator or a cruise controller, determining manipulated variables u.sub.m(t), by means of which the actuators ACT.sub.m are actuated such that when contact occurs with the surface of an object, the end effector acts on said object with a predefined force winder {right arrow over (F)}.sub.D(t)={{right arrow over (f)}.sub.D(t),{right arrow over (m)}.sub.D(t)}; where,
u.sub.m(t)=u.sub.m,R1(t)+u.sub.m,R2(t),(1) where: {right arrow over (f)}.sub.D(t):=predefined force; {right arrow over (m)}.sub.D(t):=predefined torque, u.sub.m,R1(t):=ratio of manipulated variables of the first regulator R1, and u.sub.m,R2(t):=ratio of manipulated variables of the second regulator R2, wherein the first regulator R1 determines the manipulated variable u.sub.m,R1(t) as product of a manipulated variable u.sub.m,R1(t)* and a function S(v(t)))) or as a function S*(v*(t), u.sub.m,R1(t)*), where:
u.sub.m,R1(t)=S(v(t)).Math.u.sub.m,R1(t)*(2a)
u.sub.m,R1(t)=S*(v*(t),u.sub.m,R1(t)*)(2b)
v(t)=v({right arrow over (F)}.sub.D(t),{right arrow over (R)}(t))(3a)
v*(t)=v*({right arrow over (F)}.sub.D(t),{right arrow over (R)}(t))=[v.sub.1*({right arrow over (F)}.sub.D(t),{right arrow over (R)}(t)), . . . ,v.sub.Q*({right arrow over (F)}.sub.D(t),{right arrow over (R)}(t))]v*(t)=[v.sub.1*(t),v.sub.2*(t), . . . ,V.sub.Q*(t)](3b)
v(t)[v.sub.a,v.sub.e](4a)
v.sub.1*(t)[v.sub.1a,v.sub.1e],v.sub.2*(t)[v.sub.2a,v.sub.2e], . . . ,v.sub.Q*(t)[v.sub.Qa,v.sub.Qe](4b) where: u.sub.m,R1*(t):=a manipulated variable determined by the first regulator R1 for generation of the predefined force winder {right arrow over (F)}.sub.D(t), {right arrow over (R)}(t):=a provided negative deviation of the regulator, S(v(t)):=a monotonically decreasing function of v(t), which depends on {right arrow over (F)}.sub.D(t) and {right arrow over (R)}(t), S*(v*(t), u.sub.m,R1(t)*):=a function, wherein the influence of u.sub.m,R1(t)* is monotonically decreasing, [v.sub.a, v.sub.e]:=a predefined definition area of the variable Variable v(t), [v.sub.1a, v.sub.1b,], . . . :=component-wise predefined definition area of Q-dimensional variable v*(t).

10. The method according to claim 9, wherein, in case the object is elastic and therefore its surface is flexible, the regulator takes into consideration predefined elasticity properties of the object when determining the manipulated variables u.sub.m(t).

11. The method according to claim 9 wherein a second unit is present, which serves as energy storage for passivation of the regulator, and which stores energy T1 coming from the regulator according to predefined energy storage dynamics, and delivers energy T2 to the regulator, wherein the second unit and the regulator form a closed-loop, and an initialization of the second unit with an energy T0 depends on a determined or predefined expenditure of energy E.sub.Expenditure to implement a current task of the robot manipulator.

12. A computer system, having a data processing device, wherein the data processing device is designed such that a method according to claim 9 is run on the data processing device.

13. A digital storage media having electronically readable control signals, wherein the control signals can interact with a programmable computer system in such way that a method according to claim 9 is run.

14. A computer program product having a program code stored on a machine-readable carrier to implement the method according to claim 9, if the program code is run on a data processing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In the drawings:

[0073] FIGS. 1a-c show a conceptionally simplified diagram to illustrate a suggested hybrid regulator having an impedance regulator and a force regulator;

[0074] FIG. 2 shows a model system illustration for performing open-loop and closed loop control of a robot manipulator, which interacts with the environment;

[0075] FIG. 3a shows a schematized illustrated impedance controlled robot manipulator having an end effector EFF and a predefined translational robustness region d.sub.max;

[0076] FIG. 3b shows a regulator shaping function ()=S(v(t)) for the translational case;

[0077] FIG. 4 shows a graph for deformation of elastic material by means of applied pressure of the end effector in the translational case;

[0078] FIG. 5 shows a schematized flow chart of a suggested device; and

[0079] FIG. 6 shows a schematized flow chart of a suggested method.

DETAILED DESCRIPTION

[0080] FIG. 1 shows a conceptionally simplified diagram to illustrate a suggested hybrid regulator having an impedance regulator and a force regulator. Dampers are not shown for reasons of clarity. FIG. 1a shows a pure impedance controlled robot manipulator having an end effector EFF. The impedance control is indicated by the illustrated spring. FIG. 1b shows a pure force regulated robot manipulator having an end effector EFF, which presses with a predefined force F.sub.d against an object surface (shaded line). FIG. 1c shows a combination of the force regulator and the impedance regulator according to the invention from FIG. 1a and FIG. 1b.

[0081] FIG. 2 shows a model system illustration for performing open-loop and closed loop control of a robot manipulator according to the invention having an end effector, which interacts with an environment/object/workpiece. Represented as function blocks are the environment (=: environment), which interacts with the robot manipulator (=: rigid body dynamics) and the actuators (=: motor dynamics). The control and regulation of the actuators is implemented by means of a regulator (=: force/impedance regulator), to which an energy tank (=: energy tank) can be coupled. The connections and feedback connections of the blocks, which are interconnected with one another, are shown with the corresponding in/outputs and exchanged quantities. By decoupling of the regulator from the energy tank in case of violation of the passivity of the regulator, feedback of the external forces is annulled.

[0082] FIG. 3a shows a schematized illustrated impedance controlled robot manipulator having an end effector EFF and a predefined translational robustness region d.sub.max. p=p.sub.sp indicates the vector, which points from the end effector position p to a set point p.sub.s, wherein f.sub.d indicates the predefined force winder.

[0083] FIG. 3b shows a regulator shaping function ()=S(v(t)) for the translational case. More detailed illustrations regarding the function () can be found in the above description (cf. Part: C Stabilization of losses of contact).

[0084] FIG. 4 shows a graph for deformation of elastic material by means of applied pressure of the end effector EFF in the translational case, which illustrates in the above description in more detail (cf. Part D Handling of flexible and strongly complaint objects).

[0085] FIG. 5 shows a schematized flow chart of a suggested device for performing open-loop and closed loop control of a robot manipulator, which is driven by a number M of actuators ACT.sub.m, having an end effector, where m=1, 2, 3. The device comprises a first unit 101, which registers and/or makes available a force winder {right arrow over (F)}.sub.ext(t)={{right arrow over (f)}.sub.e, (t),{right arrow over (m)}.sub.ext(t)} acting on the end effector, where {right arrow over (f)}.sub.ext(t):=external force acting on the end effector; {right arrow over (m)}.sub.ext(t):=external torque acting on the end effector; a regulator 102, which is connected with the first unit 101 and the actuators ACT.sub.m, which comprises a first regulator R1, which is a force regulator, and a second regulator R2 connected therewith, which is an impedance regulator, wherein the regulator 102 determines manipulated variables u.sub.m(t), by means of which the actuators ACT.sub.m can be actuated in such way that when contact occurs with the surface of an object, the end effector acts on said object with a predefined force winder {right arrow over (F)}.sub.D(t)={{right arrow over (f)}.sub.D(t),{right arrow over (m)}.sub.D(t)}; wherein: u.sub.m(t)=u.sub.m,R1(t)+u.sub.m,R2(t), where: {right arrow over (f)}.sub.D(t):=predefined force; {right arrow over (m)}.sub.D(t):=predefined torque, u.sub.m,R1(t):=ratio of manipulated variables of the first regulator R1, and u.sub.m,R2(t):=ratio of manipulated variables of the second regulator R2, wherein the first regulator R1 is embodied and configured such that the manipulated variable u.sub.m,R1(t) is determined as a product of a manipulated variable u.sub.m,R1(t)* and a function S(v(t)), wherein: u.sub.m,R1(t)=S(v(t)) u.sub.m,R1(t)*, v(t)=v({right arrow over (F)}.sub.D(t), {right arrow over (R)}(t)),v[v.sub.a, v.sub.e], where: u.sub.m,R1*(t):=a manipulated variable determined by the first regulator R1 to generate the predefined force winder {right arrow over (F)}.sub.D(t), {right arrow over (R)}(t):=a provided negative deviation of the regulator 102, S(v(t)):=a monotonically decreasing function of v(t), which depends on {right arrow over (F)}.sub.D(t) and {right arrow over (R)}(t), and [v.sub.a, v.sub.e]:=a predefined definition area of the variable v(t).

[0086] FIG. 6 shows a schematized flow chart of a suggested method for performing open-loop and closed loop control of a robot manipulator, which is driven by a number M of actuators ACT.sub.m, having an end effector, where m=1, 2, . . . , M. The method comprises the following steps. In a first step 201, a registering and/or making available of an external force winder {right arrow over (F)}.sub.ext(t)={{right arrow over (f)}.sub.ext(t),{right arrow over ()}.sub.ext(t)} acting on the end effector takes place, where: {right arrow over (f)}.sub.ext(t):=external force acting on the end effector; {right arrow over (m)}.sub.ext(t):=external torque acting on the end effector. A determining of manipulated variables u.sub.m(t), by means of which actuators ACT.sub.m are actuated such that, the end effector in case of contact with a surface of an object acts on said object with a predefined force winder {right arrow over (F)}.sub.D(t)={{right arrow over (f)}.sub.D(t),{right arrow over (m)}.sub.D(t)}, takes place in a second step 202 by means of a regulator 102, which comprises a first regulator R1, which is a force regulator, and a second regulator R2 connected therewith, which is an impedance regulator; wherein: u.sub.m(t)=u.sub.m,R1(t)+u.sub.m,R2(t), wherein: {right arrow over (f)}.sub.D(t):=predefined force; {right arrow over (m)}.sub.D(t):=predefined torque, u.sub.m,R1(t):=ratio of manipulated variables of the first regulator R1, and u.sub.m,R2(t):=ratio of manipulated variables of the second regulator R2, wherein the first regulator R1 determines the manipulated variable u.sub.m,R1(t) as product of a manipulated variable u.sub.m,R1(t)* and a function S(v(t)), wherein: u.sub.m,R1(t)=S(v(t)) u.sub.m,R1(t)*, v(t)=v({right arrow over (F)}.sub.D(t), {right arrow over (R)}(t)), and v[v.sub.a, v.sub.e], where: u.sub.m,R1*(t):=a manipulated variable determined by the first regulator R1 for generation of the predefined force winder {right arrow over (F)}.sub.D(t), {right arrow over (R)}(t):=a provided negative deviation of the regulator 102, S(v(t)):=a monotonically decreasing function of v(t), which depends on {right arrow over (F)}.sub.D(t) and {right arrow over (R)}(t), [v.sub.a, v.sub.e]:=a predefined definition area of the variable v(t).

[0087] Although the invention was illustrated and explained in more detail by preferred exemplary embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by the person skilled in the art without leaving the scope of protection of the invention. It is therefore understood, that a plurality of variation possibilities exists. It is also understood, that exemplary stated embodiments do indeed represent mere examples, which are not to be interpreted in any way as limitation of, e.g., the scope of protection, the application possibilities or the configuration of the invention. Rather, the previous description and the description of the figures enable the person skilled in the art to specifically implement the exemplary embodiments, wherein the person skilled in the art can implement various changes with the knowledge of the disclosed idea of the invention, for example with respect to the function or arrangement of individual elements mentioned in an exemplary embodiment, without leaving the scope of protection, which is defined by the claims and their legal equivalences, such as the further explanation in the description.