Active backdriving for a robotic arm
A robotic surgical system includes at least one robotic arm comprising at least one movable joint and an actuator configured to drive the at least one movable joint, and a controller configured to generate a first signal, the first signal comprising a first oscillating waveform having a first frequency and being modulated by a second oscillating waveform having a second frequency, wherein the second frequency is higher than the first frequency. The actuator is configured to drive the at least one movable joint based on the first signal to at least partially compensate for friction in the at least one movable joint.
1. A method for assisting movement of a robotic surgical arm having at least one movable joint, the method comprising:
generating a first signal comprising a first oscillating waveform having a first frequency and a second oscillating waveform having a second frequency, wherein the second frequency is higher than the first frequency and the second oscillating waveform is modulated on top of the first oscillating waveform; and
driving an actuator in the at least one movable joint based on the first signal to at least partially compensate for friction in the at least one movable joint.
2. The method of claim 1 , wherein the first oscillating waveform is a sine wave.
3. The method of claim 2 , wherein the first frequency is between about 1 Hz and about 5 Hz.
4. The method of claim 2 , wherein the second oscillating waveform is a sine wave.
5. The method of claim 4 , wherein the second frequency is less than or equal to about 200 Hz.
6. The method of claim 1 , further comprising detecting movement of the at least one movable joint and, in response to detecting movement of the at least one movable joint, driving the actuator in the at least one movable joint based on a second signal different from the first signal.
7. The method of claim 6 , wherein the second signal is based on a dynamic friction model.
8. The method of claim 7 , wherein the amplitude of the second signal is generally linearly proportional to a velocity of the at least one movable joint.
9. The method of claim 1 , further comprising driving the actuator in the at least one movable joint to at least partially compensate for a gravitational force acting upon the at least one movable joint.
10. A robotic surgical system, comprising:
at least one robotic arm comprising at least one movable joint and an actuator configured to drive the at least one movable joint;
a controller configured to generate a first signal, the first signal comprising a first oscillating waveform having a first frequency and a second oscillating waveform having a second frequency, wherein the second frequency is higher than the first frequency and the second oscillating waveform is modulated on top of the first oscillating waveform;
wherein the actuator is configured to drive the at least one movable joint based on the modulated signal to at least partially compensate for friction in the at least one movable joint.
11. The system of claim 10 , wherein at least one of the first and second oscillating waveforms is a sine wave.
12. The system of claim 11 , wherein the first frequency is between about 1 Hz and about 5 Hz.
13. The system of claim 11 , wherein the second frequency is less than or equal to about 200 Hz.
14. The system of claim 10 , wherein the at least one robotic arm comprises at least one sensor configured to detect movement of the at least one movable joint.
15. The system of claim 14 , wherein the actuator is configured to drive the at least one movable joint based on a second signal different from the first signal, in response to detection of movement of the at least one movable joint.
16. The system of claim 10 , wherein the second signal is based on a dynamic friction model.
17. The system of claim 16 , wherein the amplitude of the second signal is generally linearly proportional to a velocity of the at least one movable joint.
18. The system of claim 10 , wherein the actuator is configured to drive the at least one movable joint to at least partially compensate for a gravitational force acting upon the at least one movable joint.