Surgical robotic arm admittance control
Certain aspects relate to systems and techniques for surgical robotic arm admittance control. In one aspect, there is provided a system including a robotic arm and a processor. The processor may be configured to determine a force at a reference point on the robotic arm based on an output of a torque sensor and receive an indication of a direction of movement of the reference point. The processor may also determine that a component of the force is in the same direction as the direction of movement of the reference point, generate at least one parameter indicative of a target resistance to movement of the robotic arm, and control the motor, based on the at least one parameter, to move the robotic arm in accordance with the target resistance.
1. A method of driving movement of a robotic arm, comprising:
receiving an indication of a direction of movement of a reference point on a robotic arm, the robotic arm comprising at least two linkages, at least one joint connecting the at least two linkages, and at least one sensor configured to output data indicative of a force at the reference point;
determining a direction of the force at the reference point based on the data received from the at least one sensor,
determining an intent of a user manually moving the robotic arm based on a comparison of the direction of movement of the reference point and the direction of the force at the reference point; and
driving movement of the robotic arm based on the determined intent.
2. The method of claim 1 , wherein:
the robotic arm further comprises at least one motor configured to adjust the position of the at least two linkages, and
the driving of the movement of the robotic arm comprises controlling the at least one motor to move the robotic arm in accordance with the determined intent.
3. The method of claim 1 , wherein determining the intent of the user comprises:
determining that a component of the force at the reference point is in the same direction as the direction of movement of the reference point, and
determining that the intent of the user is to accelerate movement of the robotic arm in response to determining that the component of the force at the reference point is in the same direction as the direction of movement of the reference point.
4. The method of claim 1 , wherein determining the intent of the user comprises:
determining that a component of the force at the reference point is in the opposite direction as the direction of movement of the reference point, and
determining that the intent of the user is to decelerate movement of the robotic arm in response to determining that the component of the force at the reference point is in the opposite direction as the direction of movement of the reference point.
5. The method of claim 1 , wherein the at least one sensor comprises a torque sensor configured to detect torque between the at least two linkages of the robotic arm.
6. The method of claim 5 , further comprising:
determining the force at the reference point on the robotic arm based on an output of the torque sensor.
7. The method of claim 5 , further comprising:
measuring a first torque value at the at least one joint based on an output of the torque sensor;
determining a second torque value at the at least one joint based on a position of the robotic arm, the second torque value indicative of a gravitational component of the torque between the at least two linkages; and
determining the force at the reference point based on a difference between the first and second torque values.
8. The method of claim 1 , wherein:
the robotic arm further comprises an instrument device manipulator (IDM) connected to a distal end of the robotic arm, and
the reference point is located on the IDM.
9. The method of claim 1 , wherein:
the memory further comprises computer-executable instructions to cause the processor to determine a deadband of the force, and
the driving of the movement of the robotic arm is further based on restricting movement of the robotic arm to be responsive to values of the force outside of the deadband.
10. The method of claim 1 , wherein driving movement of the robotic arm comprises:
determining a first parameter defining a virtual mass of the robotic arm with respect to movement of the robotic arm, and
determining a second parameter value defining a virtual damping coefficient of the robotic arm with respect to movement of the robotic arm,
wherein the driving of the movement of the robotic arm is further based on the first parameter and the second parameter.
11. A non-transitory computer readable storage medium having stored thereon instructions that, when executed, cause at least one computing device to:
receive an indication of a direction of movement of a reference point on a robotic arm, the robotic arm comprising at least two linkages, at least one joint connecting the at least two linkages, and at least one sensor configured to output data indicative of a force at the reference point,
determine a direction of the force at the reference point based on the data received from the at least one sensor,
determine an intent of a user manually moving the robotic arm based on a comparison of the direction of movement of the reference point and the direction of the force at the reference point, and
drive movement of the robotic arm based on the determined intent.
12. The non-transitory computer readable storage medium of claim 11 , wherein:
the robotic arm further comprises at least one motor configured to adjust the position of the at least two linkages, and
the driving of the movement of the robotic arm comprises controlling the at least one motor to move the robotic arm in accordance with the determined intent.
13. The non-transitory computer readable storage medium of claim 11 , wherein the instructions that cause at least one computing device to determine the intent of the user further cause the at least one computing device to:
determine that a component of the force at the reference point is in the same direction as the direction of movement of the reference point, and
determine that the intent of the user is to accelerate movement of the robotic arm in response to determining that the component of the force at the reference point is in the same direction as the direction of movement of the reference point.
14. The non-transitory computer readable storage medium of claim 11 , wherein the instructions that cause at least one computing device to determine the intent of the user further cause the at least one computing device to:
determine that a component of the force at the reference point is in the opposite direction as the direction of movement of the reference point, and
determine that the intent of the user is to decelerate movement of the robotic arm in response to determining that the component of the force at the reference point is in the opposite direction as the direction of movement of the reference point.
15. The non-transitory computer readable storage medium of claim 11 , wherein the at least one sensor comprises a torque sensor configured to detect torque between the at least two linkages of the robotic arm.
16. The non-transitory computer readable storage medium of claim 15 , further having stored thereon instructions that, when executed, cause at least one computing device to:
determine the force at the reference point on the robotic arm based on an output of the torque sensor.
17. The non-transitory computer readable storage medium of claim 15 , further having stored thereon instructions that, when executed, cause at least one computing device to:
measure a first torque value at the at least one joint based on an output of the torque sensor;
determine a second torque value at the at least one joint based on a position of the robotic arm, the second torque value indicative of a gravitational component of the torque between the at least two linkages; and
determine the force at the reference point based on a difference between the first and second torque values.
18. The non-transitory computer readable storage medium of claim 11 , wherein:
the robotic arm further comprises an instrument device manipulator (IDM) connected to a distal end of the robotic arm, and
the reference point is located on the IDM.
19. The non-transitory computer readable storage medium of claim 11 , wherein:
the non-transitory computer readable medium further has stored thereon instructions that, when executed, cause at least one computing device to determine a deadband of the force, and
the driving of the movement of the robotic arm is further based on restricting movement of the robotic arm to be responsive to values of the force outside of the deadband.
20. The non-transitory computer readable storage medium of claim 11 , wherein the instructions that cause at least one computing device to drive movement of the robotic arm further cause the at least one computing device to:
determine a first parameter defining a virtual mass of the robotic arm with respect to movement of the robotic arm, and
determine a second parameter value defining a virtual damping coefficient of the robotic arm with respect to movement of the robotic arm,
wherein the driving of the movement of the robotic arm is further based on the first parameter and the second parameter.
21. A system, comprising:
a robotic arm comprising:
at least two linkages,
at least one joint connecting the at least two linkages, and
at least one sensor configured to output data indicative of a force at a reference point on the robotic arm;
a processor; and
a memory storing computer-executable instructions to cause the processor to:
receive an indication of a direction of movement of the reference point,
determine a direction of the force at the reference point based on the data received from the at least one sensor,
determine an intent of a user manually moving the robotic arm based on a comparison of the direction of movement of the reference point and the direction of the force at the reference point, and
drive movement of the robotic arm based on the determined intent.
22. The system of claim 21 , wherein:
the robotic arm further comprises at least one motor configured to adjust the position of the at least two linkages, and
the driving of the movement of the robotic arm is based on controlling the at least one motor to move the robotic arm in accordance with the determined intent.
23. The system of claim 21 , wherein the computer-executable instructions that cause the processor to determine the intent of the user further cause the processor to:
determine that a component of the force at the reference point is in the same direction as the direction of movement of the reference point, and
determine that the intent of the user is to accelerate movement of the robotic arm in response to determining that the component of the force at the reference point is in the same direction as the direction of movement of the reference point.
24. The system of claim 21 , wherein the computer-executable instructions that cause the processor to determine the intent of the user further cause the processor to:
determine that a component of the force at the reference point is in the opposite direction as the direction of movement of the reference point, and
determine that the intent of the user is to decelerate movement of the robotic arm in response to determining that the component of the force at the reference point is in the opposite direction as the direction of movement of the reference point.
25. The system of claim 21 , wherein the at least one sensor comprises a torque sensor configured to detect torque between the at least two linkages of the robotic arm.
26. The system of claim 25 , wherein the memory further stores computer-executable instructions to cause the processor to:
determine the force at the reference point on the robotic arm based on an output of the torque sensor.
27. The system of claim 25 , wherein the memory further stores computer-executable instructions to cause the processor to:
measure a first torque value at the at least one joint based on an output of the torque sensor,
determine a second torque value at the at least one joint based on a position of the robotic arm, the second torque value indicative of a gravitational component of the torque between the at least two linkages, and
determine the force at the reference point based on a difference between the first and second torque values.
28. The system of claim 21 , wherein:
the robotic arm further comprises an instrument device manipulator (IDM) connected to a distal end of the robotic arm, and
the reference point is located on the IDM.
29. The system of claim 21 , wherein:
the memory further stores computer-executable instructions to cause the processor to determine a deadband of the force, and
the driving of the movement of the robotic arm is further based on restricting movement of the robotic arm to be responsive to values of the force outside of the deadband.
30. The system of claim 21 , wherein the computer-executable instructions that cause the processor to drive movement of the robotic arm further cause the processor to:
determine a first parameter defining a virtual mass of the robotic arm with respect to movement of the robotic arm, and
determine a second parameter value defining a virtual damping coefficient of the robotic arm with respect to movement of the robotic arm,
wherein the driving of the movement of the robotic arm is further based on the first parameter and the second parameter.