Surgical manipulator

• US 20070299427A1
• Filed: 06/14/2007
• Published: 12/27/2007
• Est. Priority Date: 06/14/2006
• Status: Active Grant

• Current Assignee: Macdonald Dettwiler and Associates Limited
• Original Assignee: Macdonald Dettwiler and Associates Limited
• Inventors: Gregoris, Dennis, Bednarz, Bronislaw, Gray, Michael, Yeung, Benny
• Granted Patent: US 8,491,603 B2
• Time in Patent Office: Days
• US Class Current: 606/1
• CPC Class Codes: A61B 2034/305 Details of wrist mechanisms at distal ends of robotic arms
• CPC Class Codes: A61B 2034/715 Cable tensioning mechanisms for removing slack
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: A61B 34/37 Master-slave robots A61B34/35 takes precedence
• CPC Class Codes: A61B 34/71 Manipulators operated by drive cable mechanisms
• CPC Class Codes: A61B 34/77 Manipulators with motion or force scaling
• CPC Class Codes: A61B 46/10 specially adapted for instruments, e.g. microscopes
• CPC Class Codes: A61B 90/361 Image-producing devices, e.g. surgical cameras
• CPC Class Codes: B25J 9/047 the pivoting axis of the first arm being offset to the vertical axis
• CPC Class Codes: B25J 9/104 with cables, chains or ribbons

Abstract

The present invention provides a surgical manipulator including a manipulator arm, an end-effector held by the robotic arm, surgical tools held by the end-effector and manipulator joints, particularly right-angle drive devices for transmitting rotational motion in one axis to a perpendicular axis.

Claims

1. A surgical manipulator, comprising:

a) a base and a first right-angle drive mechanism mounted on said base, a shoulder-roll drive mechanism located in said base for rotating said first right-angle drive mechanism about a shoulder-roll axis, said first right-angle drive mechanism including a first input pulley and a first output pulley mounted substantially perpendicular to said input pulley;

said first right-angle drive mechanism including a bi-directional coupling mechanism for coupling said first input pulley and said first output pulley, a first drive mechanism for rotating said first input pulley about a first input axis wherein rotation of said first input pulley is translated into rotation of said first output pulley by said bi-directional coupling mechanism about a shoulder-pitch axis which is substantially perpendicular to said first input axis;

b) a lower robotic arm being mounted at one end thereof to said first output pulley so that when said first output pulley is rotated, said lower arm rotates about said shoulder-pitch axis;

c) a second right-angle drive mechanism mounted in said lower robotic arm, said second right-angle drive mechanism including a second input pulley and a second output pulley mounted substantially perpendicular to said second input pulley,

said second right-angle drive mechanism including said first drive mechanism and said bi-directional coupling mechanism for coupling said second input pulley and said second output pulley, wherein rotation of said second input pulley about a second input axis is translated into rotation of said second output pulley by said bi-directional coupling mechanism about an elbow-pitch axis substantially perpendicular to said second input axis;

d) a robotic fore arm mounted on said second output pulley of said second right-angle drive mechanism so that when said second output pulley is rotated, said robotic fore arm rotates about said elbow-pitch axis;

e) a third right-angle drive mechanism mounted in said robotic fore arm, said third right-angle drive mechanism including a third input pulley and a third output pulley mounted substantially perpendicular to said second input pulley,

said third right-angle drive mechanism including said first drive mechanism and said bi-directional coupling mechanism for coupling said third input pulley and said third output pulley, wherein rotation of said third input pulley about a third input axis is translated into rotation of said third output pulley by said bi-directional coupling mechanism about a wrist-pitch axis substantially perpendicular to said third input axis;

f) a robotic wrist mounted on said third output pulley of said third right-angle drive mechanism so that when said third output pulley is rotated, said robotic wrist rotates about said wrist-pitch axis;

said robotic wrist including an actuation mechanism coupled to a wrist output shaft for rotating said robotic wrist output shaft about a wrist-roll axis; and

g) an end-effector mounted to said wrist output shaft, said end-effector including gripping means for releasibly gripping a surgical tool wherein when said actuation mechanism is engaged said end-effector is rotated about said wrist-roll axis.

2. The surgical manipulator according to claim 1 wherein said first drive mechanism includes a spur-gear mechanism mounted in said base and including a pinion anti-backlash gear meshed with a driven gear, a motor for rotating said pinion gear which in turn rotates said driven gear and therefore the first right angle drive mechanism about a shoulder-roll axis, and including a motor brake.

3. The surgical manipulator according to claim 2 wherein said motor includes a servo motor integrated with a harmonic gear and an angular encoder for measuring rotational displacement of a motor shaft coupled to said pinion gear.

4. The surgical manipulator according to claim 1 wherein said end-effector includes

a main body portion including a frame, a tool-yaw motor mounted on said frame, a tool-actuation motor mounted on said frame,

a tool holder mounted on said frame and being detachable therefrom, said tool holder being configured to hold said surgical tool,

a tool-actuation mechanism mounted on said frame and being detachable therefrom, said tool-actuation mechanism being configured to engage a piston on said surgical tool, said tool-actuation mechanism being coupled to said tool-actuation motor,

and a tool-yaw drive mechanism mounted on said frame and being detachable therefrom, said tool-yaw drive mechanism being coupled to said tool-yaw motor, wherein upon activation of said tool-yaw drive mechanism said surgical tool rotates about said tool-yaw axis and wherein upon activation of said tool-actuation mechanism said piston is linearly retracted or linearly extended with respect to said end-effector thereby activating a tool portion of said surgical tool.

5. The surgical manipulator according to claim 4 wherein said end-effector includes a base block which interfaces to the wrist, and wherein said end-effector includes a tool-tip force-moment sensor which is a single mechanical linkage between said motor-support bracket and said base block.

6. The surgical manipulator according to claim 4 wherein said tool-actuation motor is a linear actuator having an output shaft which moves up and down along a major axis of the motor and at a distal end portion of said output shaft an actuator bar is connected at a first end portion thereof, said actuator bar having a second end portion supported by a vertical guide rod and including an interface which couples to said tool-actuation mechanism, wherein said actuator bar transmits vertical motion of the output shaft to the tool-actuation mechanism which is mounted at the second end of the bar such that said vertical motion provides a tool-actuation axis of motion for the end-effector.

7. The surgical manipulator according to claim 6 wherein said end-effector includes a tool-actuation force sensor mounted on said actuation bar between a point where said actuation bar is supported by the vertical guide rod and the interface with the tool-actuation mechanism.

8. The surgical manipulator according to claim 7 wherein said tool-actuation force sensor is a strain gauge, at which point on the bar on which said force sensor is mounted any elastic vertical deflection due to actuation of the surgical tool can be measured.

9. The surgical manipulator according to claim 4 wherein said tool-yaw mechanism includes a frame, on which is mounted a pair of idler pulleys, a middle idler pulley and a drive pulley, including a toothed belt being routed on said idler pulleys, said middle idler pulley and said drive pulley, said toothed belt being configured to engage a toothed pulley on said surgical tool, on two opposite ends of a diameter of said toothed pulley, and wherein bi-directional rotation of the toothed belt driven by the drive pulley, converts tangential forces to rotary motion of said surgical tool.

10. The surgical manipulator according to claim 9 wherein said frame has an open front-framed architecture and a toothed belt routing configuration on said idler pulleys and said middle idler pulley configured to allow the surgical tool to be ejected/replaced from the open front of the end-effector.

11. The surgical manipulator according to claim 9 wherein said frame includes sheet metal flexures supporting said outer idler pulleys so that said outer idler pulleys can be passively spread out enough to completely disengage the surgical tool thereby eliminating any frictional effects, and wherein when engaged with said surgical tool, the metal flexures allow a constant preload to the toothed belt during tool yawing but can also manually collapse, when no surgical tool is present, for facilitating toothed belt replacement.

12. The surgical manipulator according to claim 9 wherein said tool-yaw motor mounted on said frame includes a drive shaft having a shape complementary to a shape of a bore on the drive pulley for insertion into the bore for enabling torque to be transmitted to the tool-yaw mechanism, while allowing easy de-coupling of the shaft from the drive pulley.

13. The surgical manipulator according to claim 9 wherein said tool-yaw motor includes a servo motor integrated with an anti-backlash spur gearhead and an incremental encoder.

14. The surgical manipulator according to claim 4 wherein said magnetic tool holder, said tool actuator, and said tool-yaw mechanism are sterile subassemblies, with quick release and attachment features for quickly attaching and detaching them to and from said main body portion.

15. The surgical manipulator according to claim 4 wherein said main assembly including said tool-yaw motor, said tool-actuation motor, said tool-tip force-moment sensor and said tool-actuation force sensor are encapsulated in a protective drape bag which covers from the base of the surgical manipulator all the way through the entire length of the robotic fore arm, lower arm and robotic wrist and up to a front face of the end-effector main assembly.

16. The surgical manipulator according to claim 2 wherein said tool holder includes a support body having an elongate channel having a size suitable to receive therein the cylindrical tool body of surgical tool, and wherein said cylindrical tool body is made of a magnetic material, and wherein said support body includes at least one magnet embedded therein adjacent to said groove for magnetically restraining said magnetic cylindrical tool body.

17. The surgical manipulator according to claim 16 wherein said support body is made of a material which allows the surgical tool to rotate with minimal friction within support body when rotated by said tool-yaw mechanism.

18. The surgical manipulator according to claim 16 wherein said surgical tool includes flanges on the body of the surgical tool for locating and constraining the surgical tool axially within said channel in support body due to a close axial fit with the support body.

19. The surgical manipulator according to claim 16 wherein said tool holder includes a tool release mechanism including a pair of tool-ejection wings pivotally mounted on support body with a portion of each wing located in said channel behind said tool body and configured such that once said tool-ejection wings compressed on outer surfaces thereof, tool-ejection wings pivot in a scissor action, to strip the tool body away from said at least one magnet responsively ejecting said tool from said tool holder.

20. The surgical manipulator according to claim 19 wherein said tool-actuation mechanism includes a pair of pivoting fingers pivotally mounted to a support member with matched end portions configured to engage and hold therebetween a portion of a piston on the surgical tool.

21. The surgical manipulator according to claim 20 including a tool changer mechanism comprising a tool storage and tool change tray, said tool change tray including a support structure for holding the surgical tools and including engaging features arrayed on said tool change tray configured to simultaneously spread said pulleys apart, engage the pivoting fingers located on said tool-actuation mechanism, and engage said ejection-wings located on said tool holder thereby releasing said surgical tool from said end-effector.

22. The surgical manipulator according to claim 21 wherein said support structure for holding the surgical tools and said engaging features arrayed on said tool change tray include first and second pair of pins fixed in vertical arrangement to said tool tray being positioned and spaced apart such that they engage said pulleys on said tool-yaw mechanism and spread said pulleys apart when said end-effector engages said passive tool changer when picking up a surgical tool or releasing a surgical tool, and including a third pair of pins positioned on said tool change tray with respect to said first and second pairs of pins such that the third pair of pins engage pivoting fingers located on said tool-actuation mechanism responsively pivoting said fingers out of engagement with said piston on said surgical tool, said tool change tray including mating ejection latches mounted on the tool tray which line up with said ejection-wings located on said tool holder, which mating ejection latches include a spring-loaded pliers-like mechanism to provide a cushioned tool-ejection.

23. The surgical manipulator according to claim 21 wherein each surgical tool includes identifying means mounted thereon, and wherein said tool changer includes a tool-identification sensor for said identifying means.

24. The surgical manipulator according to claim 23 wherein said identifying means includes a radio frequency (rf) tag and, and wherein said reading means includes an rf receiver.

25. The surgical manipulator according to claim 23 wherein said identifying means includes a bar code, and wherein said reading means includes a bar code reader.

26. The surgical manipulator according to claim 1 wherein said surgical manipulator is a first surgical manipulator, including at least a second surgical manipulators and configured to be structural mirror images of each other, said first surgical manipulator being configured for left handed operation and said at least a second surgical manipulator being configured for right handed operation to allow the surgical tools attached to respective end-effectors to be brought into closest proximity with each other in a surgical site on a patient.

27. The surgical manipulator according to claim 1 wherein said first, second and third right-angle drive mechanisms each include

a) a housing and wherein said first drive mechanism includes a harmonic drive mounted on said housing being connected to said input pulley for rotation about said first rotational axis;

b) the output drive shaft having a second axis of rotation, said output shaft being connected to said output pulley, said output pulley being mounted in said housing for rotation about said second rotational axis, said input and output pulleys being mounted in said housing and positioned with respect to each other such that a pre-selected angle is established between said first and second axes of rotation;

c) said bi-directional coupling mechanism for coupling said first input pulley and said first output pulley comprising

a cable drive mounted in said housing, said cable drive including,

at least one flexible cable, said input and output pulleys each including at least one cable guide for receiving therein said at least one flexible cable,

idler means for guiding said at least one flexible cable between said input and output pulleys,

wherein when the input pulley rotates in one direction about said first axis of rotation, said at least one flexible cable pulls the output pulley and output shaft to rotate in one direction about said second rotational axis, and when the input pulley rotates in the other direction about said first axis of rotation, said at least one flexible cable pulls the output pulley and output shaft to rotate in an opposite direction about said second rotational axis.

28. A surgical manipulator system, comprising:

a) at least first and second surgical manipulators according to claim 26;

b) left and right hand controllers with the right hand controller being associated with the first surgical manipulator and the left hand controller being associated with the second surgical manipulator, said at least first and second hand controllers being configured to be operated by a surgeon; and

c) communication system coupling said left and right hand controllers to said at least first and second surgical manipulators for translating movement of said left and right hand controllers to scaled movement of said at least first and second surgical manipulators.

29. The surgical system according to claim 28 including a vision system focused on a work area including an area of a patient to be operated on and focused on the end-effectors and associated surgical tools attached to said at least two surgical manipulators, said vision system including display means for displaying images of said work area to a surgeon.

30. The surgical system according to claim 29 including a vision system focused on a work area including an area of a patient to be operated on and focused on the end-effectors and associated surgical tools attached to said at least two surgical manipulators, said vision system including display means for displaying images of said work area to a surgeon.

31. The surgical system according to claim 29 configured for teleoperation wherein said surgeon is located remotely from said patient.

32. The surgical system according to claim 28 wherein said end-effector includes a tool-tip force-moment sensor mounted to said end-effector and configured to sense tool tip force and moment at a tip of the surgical tool, and wherein said end-effector includes a tool-actuation force sensor mounted thereon configured to measure actuation forces on a tip of the surgical tool, and wherein said communication system coupling said left and right hand controllers to said at least first and second surgical manipulators is configured to communicate said forces and moments to said left and right handed controllers providing haptic feedback to said surgeon.

33. The surgical manipulator according to claim 32 wherein said tool-actuation force sensor is a strain gauge.

34. A drive device for transmitting rotational motion about one axis to rotational motion about another axis, comprising:

a) a housing and a harmonic drive mounted on said housing being connected to an input pulley for rotation about a first rotational axis;

b) an output drive shaft having a second axis of rotation, said output shaft being connected to an output pulley, said output pulley being mounted in said housing for rotation about said second rotational axis, said input and output pulleys being mounted in said housing and positioned with respect to each other such that a pre-selected angle is established between said first and second axes of rotation;

c) bi-directional coupling mechanism for coupling said first input pulley and said first output pulley, comprising

a cable drive mounted in said housing, said cable drive including,

at least one flexible cable, said input and output pulleys each including at least one cable guide for receiving therein said at least one flexible cable,

idler means for guiding said at least one flexible cable between said input and output pulleys,

wherein when the input pulley rotates in one direction about said first axis of rotation, said at least one flexible cable pulls the output pulley and output shaft to rotate in one direction about said second rotational axis, and when the input pulley rotates in the other direction about said first axis of rotation, said at least one flexible cable pulls the output pulley and output shaft to rotate in an opposite direction about said second rotational axis.

35. The drive device according to claim 34 wherein said at least one flexible cable is a pair of flexible cables, said input pulley including a first circular section having a first diameter and a second circular section having at least a second diameter rigidly attached to said first circular section, said at least a second diameter being smaller than said first diameter, a circumference of the first and said at least a second circular sections each having a groove with the groove in the circumference of the first section for receiving therein a first flexible cable of said pair of flexible cables and the groove in the circumference of the at least a second section for receiving therein a second flexible cable of said pair of flexible cables, said idler means including a pair of idlers each having an idler shaft and a first and at least a second idler pulley mounted in said housing and aligned along an axis perpendicular to said first and second rotational axis with said first idler pulley configured for guiding said first flexible cable between said grooves on the first sections of said input and output pulleys, and said at least a second idler pulley configured for guiding said at least a second flexible cable between said grooves on said at least a second sections on said input and output pulleys.

36. The drive device according to claim 35 wherein said cable drive includes a cable tension adjustment mechanism for adjusting a tension of said at least one flexible cable.

37. The drive device according to claim 36 wherein said cable tension adjustment mechanism is manually operable to eliminate any slack in said at least one cable.

38. The drive device according to claim 36 wherein said cable tension adjustment mechanism includes an autotensioning spring mechanism configured apply tension to said at least one cable to eliminate any slack in said at least one cable.

39. The drive device according to claim 36 wherein said cable tension adjustment mechanism includes an autotensioning racheting mechanism configured to rachet said at least one cable to eliminate any slack in said at least one cable and lock said autotensioning racheting mechanism.

40. The drive device according to claim 34 wherein said at least one cable is four cables, and wherein said cable drive includes cable tension adjustment means for adjusting a tension of said at least one flexible cable, said cable tension adjustment means including at least four tensioning screws connected to said output pulley, said at least four cables each having two ends and being connected at one end thereof to said tensioning screw and connected at the other end thereof to a termination at said input pulley, wherein a tension in said each cable is adjusted by turning the corresponding said tensioning screw.

41. The drive device according to claim 34 wherein said harmonic drive connected to said input pulley is configured to provide a substantially backlash free output.

42. The drive device according to claim 34 wherein said input and output pulleys are mounted in said housing in said pre-selected position such that said pre-selected angle established between said first and second axes of rotation is 90 degrees so that said second axis is perpendicular to said first axis.

43. The drive device according to claim 34 including a positioning mechanism mounted in said housing for adjusting the position of said output pulley with respect to said input pulley so that said pre-selected angle established between said first and second axes of rotation is adjustable.

44. The drive device according to claim 34 wherein said at least one flexible cable is a low-stretch/pre-tensioned cable to minimize transmission loss due to elastic stretching of the cable.

45. The drive device according to claim 34 including a sensor engaged with said output shaft for measuring rotational displacement or speed or both of said output shaft.

46. The drive device according to claim 34 including a brake configured to engage with said output shaft to provide mechanical braking action to the output shaft.

47. A surgical end-effector, comprising:

a main body portion including a frame having an interface configured to be attached to a robotic arm, a tool-yaw motor mounted on said frame, a tool-actuation motor mounted on said frame;

a tool holder mounted on said frame and being detachable therefrom, said tool holder being configured to hold a surgical tool;

a tool-actuation mechanism mounted on said frame and being detachable therefrom, said tool-actuation mechanism being configured to engage a piston on said surgical tool, said tool-actuation mechanism being coupled to said tool-actuation motor; and

and a tool-yaw drive mechanism mounted on said frame and being detachable therefrom, said tool-yaw drive mechanism being coupled to said tool-yaw motor, wherein upon activation of said tool-yaw drive mechanism said surgical tool rotates about said tool-yaw axis and wherein upon activation of said tool-actuation mechanism said piston is linearly retracted or linearly extended with respect to said end-effector thereby activating a tool portion of said surgical tool.

48. The surgical end-effector according to claim 47 wherein said interface includes a base block which interfaces to a wrist of a robotic arm, and wherein said end-effector includes a tool-tip force-moment sensor which is a single mechanical linkage between said motor-support bracket and said base block.

49. The surgical end-effector according to claim 47 wherein said tool-actuation motor is a linear actuator having an output shaft which moves up and down along a major axis of the motor and at a distal end portion of said output shaft an actuator bar is connected at a first end portion thereof, said actuator bar having a second end portion supported by a vertical guide rod and including an interface which couples to said tool-actuation mechanism, wherein said actuator bar transmits vertical motion of the output shaft to the tool-actuation mechanism which is mounted at the second end of the bar such that said vertical motion provides a tool-actuation axis of motion for the end-effector.

50. The surgical end-effector according to claim 49 including a tool-actuation force sensor mounted on said actuation bar between a point where said actuation bar is supported by the vertical guide rod and the interface with the tool-actuation mechanism.

51. The surgical end-effector according to claim 50 wherein said tool-actuation force sensor is a strain gauge, at which point on the bar on which said force sensor is mounted any elastic vertical deflection due to actuation of the surgical tool can be measured.

52. The surgical end-effector according to claim 47 wherein said tool-yaw mechanism includes a frame, on which is mounted a pair of idler pulleys, a middle idler pulley and a drive pulley, including a toothed belt being routed on said idler pulleys, said middle idler pulley and said drive pulley, said toothed belt being configured to engage a toothed pulley on said surgical tool, on two opposite ends of a diameter of said toothed pulley, and wherein bi-directional rotation of the toothed belt driven by the drive pulley converts tangential forces to rotary motion of said surgical tool.

53. The surgical end-effector according to claim 52 wherein said frame has an open front-framed architecture and a toothed belt routing configuration on said idler pulleys and said middle idler pulley configured to allow the surgical tool to be ejected/replaced from the open front of the end-effector.

54. The surgical end-effector according to claim 52 wherein said frame includes sheet metal flexures supporting said outer idler pulleys so that said outer idler pulleys can be passively spread out enough to completely disengage the surgical tool thereby eliminating any frictional effects, and wherein when engaged with said surgical tool, the metal flexures allow a constant preload to the toothed belt during tool yawing but can also manually collapse, when no surgical tool is present, for facilitating toothed belt replacement.

55. The surgical end-effector according to claim 52 wherein said tool-yaw motor mounted on said frame includes a drive shaft having a shape complementary to a shape of a bore on the drive pulley for insertion into the bore for enabling torque to be transmitted to the tool-yaw mechanism, while allowing easy de-coupling of the shaft from the drive pulley.

56. The surgical end-effector according to claim 52 wherein said tool-yaw motor includes a servo motor integrated with an anti-backlash spur gearhead and an incremental encoder.

57. The surgical end-effector according to claim 47 wherein said magnetic tool holder, said tool actuator, and said tool-yaw mechanism are sterile subassemblies, with quick release and attachment features for quickly attaching and detaching them to and from said main body portion.

58. The surgical end-effector according to claim 47 wherein said main assembly including said tool-yaw motor, said tool-actuation motor, said tool-tip force-moment sensor and said tool-actuation force sensor are encapsulated in a protective drape bag which covers from the base of the surgical manipulator all the way through the entire length of the robotic fore arm, lower arm and robotic wrist and up to a front face of the end-effector main assembly.

59. The surgical end-effector according to claim 47 wherein said tool holder includes a support body having an elongate channel having a size suitable to receive therein the cylindrical tool body of surgical tool, and wherein said cylindrical tool body is made of a magnetic material, and wherein said support body includes at least one magnet embedded therein adjacent to said groove for magnetically restraining said magnetic cylindrical tool body.

60. The surgical end-effector according to claim 59 wherein said support body is made of a material which allows the surgical tool tool to rotate with minimal friction within support body when rotated by said tool-yaw mechanism.

61. The surgical end-effector according to claim 59 wherein said surgical tool includes flanges on the body of the surgical tool for locating and constraining the surgical tool axially within said channel in support body due to a close axial fit with the support body.

62. The surgical end-effector according to claim 59 wherein said tool holder includes a tool release mechanism including a pair of tool-ejection wings pivotally mounted on support body with a portion of each wing located in said channel behind said tool body and configured such that once said tool-ejection wings compressed on outer surfaces thereof, tool-ejection wings pivot in a scissor action, to strip the tool body away from said at least one magnet responsively ejecting said tool from said tool holder.

63. The surgical end-effector according to claim 62 wherein said tool-actuation mechanism includes a pair of pivoting fingers pivotally mounted to a support member with matched end portions configured to engage and hold therebetween a portion of a piston on the surgical tool.