Method and device for open-loop/closed-loop control of a robot manipulator

1. A method of controlling a robot manipulator, the robot manipulator comprising a sensor to detect an external force {right arrow over (F)}(t) acting on the robot manipulator during mechanical interaction of the robot manipulator with an environment, wherein the method comprises:

controlling a movement speed |{right arrow over (V)}(t)| or a movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator based on speed or torque control, or speed and torque control, depending on predetermined medical parameters;

determining a force-time curve of the external force {right arrow over (F)}(t) acting on the robot manipulator detected by the sensor;

determining a time span Δt 1 extending from a time t 0 when a value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than a defined threshold value G 1 to a subsequent time t 1 when a first maximum Max1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein the defined threshold value G1<the first maximum Max1(|{right arrow over (F)}(t)|);

determining a time span Δt 2 extending from the time t 1 to a subsequent time t 2 when a first minimum Min1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein an overall time span Δt G =Δt 1 +Δt 2 , and wherein the first minimum Min1(|{right arrow over (F)}(t)|)<the first maximum Max1(|{right arrow over (F)}(t)|); and

activating a safety mode of the robot manipulator when the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) in the force-time curve is greater than the defined threshold value G1: |{right arrow over (F)}(t)|>G1, and the overall time span Δt G is less than a defined threshold value G2: Δt G <G2 or the first maximum Max1(|{right arrow over (F)}(t)|) is greater than a defined threshold G3: Max1(|{right arrow over (F)}(t)|)>G3, wherein in the safety mode the movement speed |{right arrow over (V)}(t)| or the movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator is controlled based on the external force {right arrow over (F)}(t).

2. The method according to claim 1 , wherein in the safety mode, an actuator of the robot manipulator is controlled based on the external force {right arrow over (F)}(t).

3. The method according to claim 2 , wherein a torque generated by the actuator, a position of the actuator, or a speed of the actuator is individually limited based on the external force {right arrow over (F)}(t).

4. The method according to claim 1 , wherein for G1=0.

5. The method according to claim 1 , wherein the method further comprises stopping a current movement of the robot manipulator when for a time t>t 2 , the value |{right arrow over (F)}(t)| of the force {right arrow over (F)}(t) exceeds a defined threshold value G4:|{right arrow over (F)}(t)|>G4.

6. The method according to claim 5 , wherein after stopping the current movement of the robot manipulator, the method further comprises:

carrying out previous movement of the robot manipulator in a reverse direction until the value |{right arrow over (F)}(t)| of the force {right arrow over (F)}(t) is less than a defined threshold value G5: |{right arrow over (F)}(t)|<G5; and

stopping the robot manipulator again after carrying out the previous movement of the robot manipulator.

7. The method according to claim 6 , wherein G5=0.

8. The method according to claim 1 , wherein the method further comprises:

carrying out gravitation compensation of the robot manipulator when for a time t>t 2 , the value |{right arrow over (F)}(t)| of the force {right arrow over (F)}(t) exceeds a defined threshold value G4:|{right arrow over (F)}(t)|>G4, wherein in the gravitation compensation the robot manipulator is controlled in such a manner that only a gravitation force is compensated; and

moving the robot manipulator away from at least one additional externally applied force in a compliant manner.

9. A device to control a robot manipulator, the device comprising:

a sensor to detect an external force {right arrow over (F)}(t) acting on the robot manipulator during mechanical interaction of the robot manipulator with an environment; and

a control unit configured to:

control a movement speed |{right arrow over (V)}(t)| or a movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator based on speed or torque control, or speed and torque control, depending on predetermined medical parameters;

determine a force-time curve of the external force {right arrow over (F)}(t) acting on the robot manipulator detected by the sensor;

determine a time span Δt 1 extending from a time t 0 when a value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than a defined threshold value G1 to a subsequent time t 1 when a first maximum Max1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein the defined threshold value G1<the first maximum Max1(|{right arrow over (F)}(t)|);

determine a time span Δt 2 extending from the time t 1 to a subsequent time t 2 when a first minimum Min1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein an overall time span Δt G =Δt 1 +Δt 2 , and wherein the first minimum Min1(|{right arrow over (F)}(t)|)<the first maximum Max1(|{right arrow over (F)}(t)|); and

activate a safety mode of the robot manipulator when the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than the defined threshold value G1: |{right arrow over (F)}(t)|>G1, and the overall time span Δt G is less than a defined threshold value G2: Δt G <G2 or the first maximum Max1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than a defined threshold G3: Max1(|{right arrow over (F)}(t)|)>G3, wherein in the safety mode the movement speed |{right arrow over (V)}(t)| or the movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator is controlled based on the external force {right arrow over (F)}(t).

10. The device according to claim 9 , wherein the robot manipulator comprises an actuator, and the control unit is configured to control the actuator based on the external force {right arrow over (F)}(t).

11. The device according to claim 10 , wherein the control unit is configured to individually limit a torque generated by the actuator, a position of the actuator, or a speed of the actuator based on the external force {right arrow over (F)}(t).

12. The device according to claim 9 , wherein G1=0.

13. The device according to claim 9 , wherein the control unit is configured to stop a current movement of the robot manipulator when for a time t>t 2 , the value |{right arrow over (F)}(t)| of the force {right arrow over (F)}(t) exceeds a defined threshold value G4: |{right arrow over (F)}(t)|>G4.

14. The device according to claim 13 , wherein after stopping the current movement of the robot manipulator, the control unit is configured to:

carry out previous movement of the robot manipulator in a reverse direction until the value |{right arrow over (F)}(t)| of the force |{right arrow over (F)}(t)| is less than a defined threshold value G5: |{right arrow over (F)}(t)|<G5; and

stop the robot manipulator again after carrying out the previous movement of the robot manipulator.

15. The device according to claim 14 , wherein G5=0.

16. The device according to claim 9 , wherein the control unit is configured to:

carry out gravitation compensation of the robot manipulator when for a time t>t 2 , the value |{right arrow over (F)}(t)| of the force {right arrow over (F)}(t) exceeds a defined threshold value G4: |{right arrow over (F)}(t)|>G4, wherein in the gravitation compensation the robot manipulator is controlled in such a manner that only a gravitation force is compensated; and

move the robot manipulator away from at least one additional externally applied force in a compliant manner.

17. A robot comprising:

a robot manipulator; and

a device to control the robot manipulator, the device comprising:

a sensor to detect an external force {right arrow over (F)}(t) acting on the robot manipulator during mechanical interaction of the robot manipulator with an environment; and

a control unit configured to:

control a movement speed |{right arrow over (V)}(t)| or a movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator based on speed or torque control, or speed and torque control, depending on predetermined medical parameters;

determine a force-time curve of the external force {right arrow over (F)}(t) acting on the robot manipulator detected by the sensor;

determine a time span Δt 1 extending from a time t 0 when a value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than a defined threshold value G1 to a subsequent time t 1 when a first maximum Max1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein the defined threshold value G1<the first maximum Max1(|{right arrow over (F)}(t)|);

determine a time span Δt 2 extending from the time t 1 to a subsequent time t 2 when a first minimum Min1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein an overall time span Δt G =Δt 1 +Δt 2 , and wherein the first minimum Min1(|{right arrow over (F)}(t)|)<the first maximum Max1(|{right arrow over (F)}(t)|); and

activate a safety mode of the robot manipulator when the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than the defined threshold value G1: |{right arrow over (F)}(t)|>G1, and the overall time span Δt G is less than a defined threshold value G2: Δt G <G2 or the first maximum Max1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than a defined threshold G3: Max1(|{right arrow over (F)}(t)|)>G3, wherein in the safety mode the movement speed |{right arrow over (V)}(t)| or the movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator is controlled based on the external force {right arrow over (F)}(t).

18. A system to control a robot manipulator, wherein the system comprises:

a processing device; and

a memory device to store a plurality of instructions that, when executed by the processing device, cause the processing device to perform operations comprising:

controlling a movement speed |{right arrow over (V)}(t)| or a movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator based on speed or torque control, or speed and torque control, depending on predetermined medical parameters;

determining a force-time curve of an external force {right arrow over (F)}(t) acting on the robot manipulator detected by a sensor, the sensor configured to detect the external force {right arrow over (F)}(t) acting on the robot manipulator during mechanical interaction of the robot manipulator with an environment; determining a time span Δt 1 extending from a time t 0 when a value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than a defined threshold value G1 to a subsequent time t 1 when a first maximum Max1(|{right arrow over (F)}(t)|) of the value |{right arrow over (V)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein the defined threshold value G1<the first maximum Max1(|{right arrow over (F)}(t)|);

determining a time span Δt 2 extending from the time t 1 to a subsequent time t 2 when a first minimum Min1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein an overall time span Δt G =Δt 1 +Δt 2 , and wherein the first minimum Min1(|{right arrow over (F)}(t)|)<the first maximum Max1(|{right arrow over (F)}(t)|); and

activating a safety mode of the robot manipulator when the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than the defined threshold value G1: |{right arrow over (F)}(t)|>G1, and the overall time span Δt G is less than a defined threshold value G2: Δt G <G2 or the first maximum Max1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than a defined threshold G3: Max1(|{right arrow over (F)}(t)|)>G3, wherein in the safety mode the movement speed |{right arrow over (V)}(t)| or the movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator is controlled based on the external force {right arrow over (F)}(t).

19. A non-transitory storage medium storing instructions that, when executed by a processing device, cause the processing device to perform operations for controlling a robot manipulator, the operations comprising:

controlling a movement speed |{right arrow over (V)}(t)| or a movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator based on speed or torque control, or speed and torque control, depending on predetermined medical parameters;

determining a force-time curve of an external force {right arrow over (F)}(t) acting on the robot manipulator detected by a sensor, the sensor configured to detect the external force {right arrow over (F)}(t) acting on the robot manipulator during mechanical interaction of the robot manipulator with an environment;

determining a time span Δt 1 extending from a time t 0 when a value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than a defined threshold value G1 to a subsequent time t 1 when a first maximum Max1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein the defined threshold value G1<the first maximum Max1(|{right arrow over (F)}(t)|);

determining a time span Δt 2 extending from the time t 1 to a subsequent time t 2 when a first minimum Min1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is reached in the force-time curve, wherein an overall time span Δt G =Δt 1 +Δt 2 , and wherein the first minimum Min1(|{right arrow over (F)}(t)|)<the first maximum Max1(|{right arrow over (F)}(t)|); and

activating a safety mode of the robot manipulator when the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than the defined threshold value G1: |{right arrow over (F)}(t)|>G1, and the overall time span Δt G is less than a defined threshold value G2: Δt G <G2 or the first maximum Max1(|{right arrow over (F)}(t)|) of the value |{right arrow over (F)}(t)| of the external force {right arrow over (F)}(t) is greater than a defined threshold G3: Max1(|{right arrow over (F)}(t)|)>G3, wherein in the safety mode the movement speed |{right arrow over (V)}(t)| or the movement direction {right arrow over (V)}(t)/|{right arrow over (V)}(t)| of the robot manipulator is controlled based on the external force {right arrow over (F)}(t).