Input device of surgical manipulator, robot-assisted surgical system, and controller

1. An input device of a surgical manipulator, the input device comprising:

an arm unit having a joint;

a wrist unit including a follower link having a base end rotatably connected to a distal end of the arm unit around a follower rotation axis, a first gimbal link having a base end rotatably connected to a distal end of the follower link and rotatable with respect to a first reference rotation position around a first gimbal rotation axis orthogonal to the follower rotation axis, a second gimbal link having a base end rotatably connected to a distal end of the first gimbal link and rotatable with respect to a second reference rotation position around a second gimbal rotation axis that is orthogonal to the first gimbal rotation axis, the first reference rotation position of the first gimbal link corresponding to a position in which the second gimbal rotation axis coincides with the follower rotation axis, and an operation unit as a third gimbal link having a base end rotatably connected to a distal end of the second gimbal link around a third gimbal rotation axis that is orthogonal to the second gimbal rotation axis, the second reference rotation position of the second gimbal link corresponding to a position in which the third gimbal axis is orthogonal to the first gimbal rotation axis;

a motor that rotates the base end of the follower link around the follower rotation axis; and

a controller configured to perform interference prevention control of a rotation position of the follower link to maintain a second rotation position of the second gimbal link using a rotation position deviation between a rotation position of the second gimbal link and the second reference rotation position as a rotation position deviation of the follower link by controlling an operation of the motor, wherein

the interference prevention control is performed only when the operation unit is operated to maintain the second rotation position by maintaining orthogonality between the first gimbal rotation axis and the third gimbal rotation axis to prevent the second gimbal link from interfering with the first gimbal link, and

the interference prevention control is stopped when the operation unit is stopped.

2. The input device of a surgical manipulator according to claim 1 , wherein the controller is configured to determine whether the operation unit is operated, and to perform the interference prevention control upon determination that the operation unit is operated.

3. The input device of a surgical manipulator according to claim 1 , wherein the controller is configured to determine whether the follower link is within a predetermined operation range, and to perform the interference prevention control upon determination that the follower link is within the predetermined operation range.

4. The input device of a surgical manipulator according to claim 1 , wherein the controller is configured to perform feedforward control of adding a rotation speed of the second gimbal link to a speed command in the interference prevention control of the rotation position of the follower link.

5. The input device of a surgical manipulator according to claim 4 , wherein the controller is configured to determine whether the follower link is within a predetermined operation range, and to perform the feedforward control upon determination that the follower link is within the predetermined operation range.

6. The input device of a surgical manipulator according to claim 5 , wherein the controller is configured to adjust an addition amount of a rotation speed of the second gimbal link to a speed command in the interference prevention control to gradually decrease as the follower link goes toward a predetermined operation range limit of the follower link, near the predetermined operation range limit of the follower link in the feedforward control.

7. The input device of a surgical manipulator according to claim 5 , wherein the controller is configured to adjust an addition amount of a rotation speed of the second gimbal link to a speed command in the interference prevention control to decrease toward zero as an absolute value of a rotation position deviation with respect to the first reference rotation position of a rotation position of the first gimbal link approaches 90 degrees from 0 degrees in the feedforward control.

8. The input device of a surgical manipulator according to claim 1 , wherein the controller is configured to perform interference prevention control to prevent the second gimbal link from interfering with the first gimbal link by maintaining a right angle between the first gimbal link and the second gimbal link.

9. A robot-assisted surgical system comprising:

a manipulator having a distal end to which a surgical tool is attached; and

an input device that operates the manipulator,

wherein the input device includes

an arm unit having a joint,

a wrist unit including a follower link having a base end rotatably connected to a distal end of the arm unit around a follower rotation axis, a first gimbal link having a base end rotatably connected to a distal end of the follower link and rotatable with respect to a first reference rotation position around a first gimbal rotation axis orthogonal to the follower rotation axis, a second gimbal link having a base end rotatably connected to a distal end of the first gimbal link and rotatable with respect to a second reference rotation position around a second gimbal rotation axis that is orthogonal to the first gimbal rotation axis, the first reference rotation position of the first gimbal link corresponding to a position in which the second gimbal rotation axis coincides with the follower rotation axis, and an operation unit as a third gimbal link having a base end rotatably connected to a distal end of the second gimbal link around a third gimbal rotation axis that is orthogonal to the second gimbal rotation axis, the second reference rotation position of the second gimbal link corresponding to a position in which the third gimbal axis is orthogonal to the first gimbal rotation axis,

a motor that rotates the base end of the follower link around the follower rotation axis, and

a controller configured to perform interference prevention control of a rotation position of the follower link to maintain the second rotation position of the second gimbal link using a rotation position deviation between a rotation position of the second gimbal link and the second reference rotation position as a rotation position deviation of the follower link by controlling an operation of the motor, wherein

the interference prevention control is performed only when the operation unit is operated to maintain the second rotation position by maintaining orthogonality between the first gimbal rotation axis and the third gimbal rotation axis to prevent the second gimbal link from interfering with the first gimbal link, and

the interference prevention control is stopped when the operation unit is stopped.

10. The robot-assisted surgical system according to claim 9 , wherein the controller is configured to determine whether the operation unit is operated, and to perform the interference prevention control upon determination that the operation unit is operated.

11. The robot-assisted surgical system according to claim 9 , wherein the controller is configured to determine whether the follower link is within a predetermined operation range, and to perform the interference prevention control upon determination that the follower link is within the predetermined operation range.

12. The robot-assisted surgical system according to claim 9 , wherein the controller is configured to perform feedforward control of adding a rotation speed of the second gimbal link to a speed command in the interference prevention control of the rotation position of the follower link.

13. The robot-assisted surgical system according to claim 12 , wherein the controller is configured to determine whether the follower link is within a predetermined operation range, and to perform the feedforward control upon determination that the follower link is within the predetermined operation range.

14. The robot-assisted surgical system according to claim 13 , wherein the controller is configured to adjust an addition amount of a rotation speed of the second gimbal link to a speed command in the interference prevention control to gradually decrease as the follower link goes toward a predetermined operation range limit of the follower link, near the predetermined operation range limit of the follower link in the feedforward control.

15. The robot-assisted surgical system according to claim 13 , wherein the controller is configured to adjust an addition amount of a rotation speed of the second gimbal link to a speed command in the interference prevention control to decrease toward zero as an absolute value of a rotation position deviation with respect to the first reference rotation position of a rotation position of the first gimbal link approaches 90 degrees from 0 degrees in the feedforward control.

16. The robot-assisted surgical system according to claim 9 , further comprising a positioner that supports the manipulator, wherein the positioner includes an articulated robot.

17. The robot-assisted surgical system according to claim 16 , further comprising a second manipulator having a distal end to which a second surgical tool is attached, wherein the positioner supports the manipulator and the second manipulator.

18. A controller configured to control an input device that operates a manipulator having a distal end to which a surgical tool is attached, wherein

the input device includes

an arm unit having a joint,

a wrist unit including a follower link having a base end rotatably connected to a distal end of the arm unit around a follower rotation axis, a first gimbal link having a base end rotatably connected to a distal end of the follower link and rotatable with respect to a first reference rotation position around a first gimbal rotation axis orthogonal to the follower rotation axis, a second gimbal link having a base end rotatably connected to a distal end of the first gimbal link and rotatable with respect to a second reference rotation position around a second gimbal rotation axis that is orthogonal to the first gimbal rotation axis, the first reference rotation position of the first gimbal link corresponding to a position in which the second gimbal rotation axis coincides with the follower rotation axis, and an operation unit as a third gimbal link having a base end rotatably connected to a distal end of the second gimbal link around a third gimbal rotation axis that is orthogonal to the second gimbal rotation axis, the second reference rotation position of the second gimbal link corresponding to a position in which the third gimbal axis is orthogonal to the first gimbal rotation axis, and

a motor that rotates the base end of the follower link around the follower rotation axis,

the controller is configured to perform interference prevention interference prevention control of a rotation position of the follower link to maintain the second rotation position of the second gimbal link using a rotation position deviation between a rotation position of the second gimbal link and the second reference rotation position as a rotation position deviation of the follower link by controlling an operation of the motor,

the interference prevention control is performed only when the operation unit is operated to maintain the second rotation position by maintaining orthogonality between the first gimbal rotation axis and the third gimbal rotation axis to prevent the second gimbal link from interfering with the first gimbal link, and

the interference prevention control is stopped when the operation unit is stopped.

19. The controller according to claim 18 , configured to determine whether the operation unit is operated, and to perform the interference prevention control upon determination that the operation unit is operated.

20. The controller according to claim 18 , configured to determine whether the follower link is within a predetermined operation range, and to perform the interference prevention control upon determination that the follower link is within the predetermined operation range.

21. The controller according to claim 18 , configured to perform feedforward control of adding a rotation speed of the second gimbal link to a speed command in the interference prevention control of the rotation position of the follower link.

22. An input device of a surgical manipulator, the input device comprising:

an arm unit having a joint;

a wrist unit including a follower link having a base end rotatably connected to a distal end of the arm unit around a follower rotation axis, a first gimbal link having a base end rotatably connected to a distal end of the follower link and rotatable with respect to a first reference rotation position around a first gimbal rotation axis orthogonal to the follower rotation axis, a second gimbal link having a base end rotatably connected to a distal end of the first gimbal link and rotatable with respect to a second reference rotation position around a second gimbal rotation axis that is orthogonal to the first gimbal rotation axis, the first reference rotation position of the first gimbal link corresponding to a position in which the second gimbal rotation axis coincides with the follower rotation axis, and an operation unit as a third gimbal link having a base end rotatably connected to a distal end of the second gimbal link around a third gimbal rotation axis that is orthogonal to the second gimbal rotation axis, the second reference rotation position of the second gimbal link corresponding to a position in which the third gimbal axis is orthogonal to the first gimbal rotation axis;

a motor that rotates the base end of the follower link around the follower rotation axis; and

a controller configured to perform interference prevention control of a rotation position of the follower link to maintain a second rotation position of the second gimbal link using a rotation position deviation between a rotation position of the second gimbal link and the second reference rotation position as a rotation position deviation of the follower link by controlling an operation of the motor, wherein

the interference prevention control is performed only when the operation unit is operated to maintain the second rotation position by maintaining orthogonality between the first gimbal rotation axis and the third gimbal rotation axis to prevent the second gimbal link from interfering with the first gimbal link, and

the rotation of the follower link is stopped when the operation unit is stopped even if a deviation in orthogonality remains between the first gimbal rotation axis and the third gimbal rotation axis.