Input device assemblies for robotic surgical systems

Patent metadata

Field	Value
Publication number	US-9987094-B2
Application number	US-201515116903-A
Country	US
Kind code	B2
Filing date	Feb 5, 2015
Priority date	Feb 7, 2014
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A reaction torque transducer for mounting a motor of an instrument drive unit includes a motor plate, a mounting plate, and a flex ring. The motor plate is fixed to the motor and the mounting plate is fixed to a fixed structure. The flex ring is positioned between the motor plate and the mounting plate. The flex ring includes a body having a first end and a second end that are moveable relative to one another. The first end of the body is fixed to the motor plate and the second end of the body is fixed to the mounting plate. The body is configured to flex in response to the first and second ends moving with respect to one another. A strain gauge is positioned on the body of the flex ring and is configured to measure flexation of the body.

First claim

What is claimed:

1. A torque transducer for mounting a motor, comprising:
a motor plate configured to be fixed to the motor;
a mounting plate configured to be fixed to fixed structure;
a flex ring positioned between the motor plate and the mounting plate, the flex ring including a body having a first end and a second end that are moveable relative to one another, the first end of the body fixed to the motor plate and the second end of the body fixed to the mounting plate, the body configured to flex in response to the first and second ends moving with respect to one another; and
a strain gauge positioned on the body of the flex ring to measure flexation of the body.

2. The torque transducer according to claim 1 , further comprising a bearing having an inner surface positioned over the motor plate and an outer surface positioned within the mounting plate.

3. The torque transducer according to claim 2 , wherein the motor plate includes a bearing stem extending towards the mounting plate and wherein the inner surface of the bearing is fixed to the bearing stem.

4. The torque transducer according to claim 2 , wherein the mounting plate includes a bearing cylinder extending towards the motor plate and wherein the outer surface of the bearing is fixed to an inner surface of the bearing cylinder.

5. The torque transducer according to claim 4 , wherein the flex ring is positioned over an outer surface of the bearing cylinder.

6. The torque transducer according to claim 2 , wherein the flex ring is positioned over the bearing.

7. The torque transducer according to claim 1 , wherein the motor plate includes a radially extending motor flange, the mounting plate includes a radially extending mounting flange, and the flex ring includes a radially extending first flange at the first end of the body and a radially extending second flange at the second end of the body, wherein the first flange is fixed to the motor flange and the second flange is fixed to the mounting flange.

8. The torque transducer according to claim 1 , wherein the body of the flex ring includes a low strain member and a high strain member each having a first end fixed to the motor ring and a second end fixed to the mounting ring.

9. The torque transducer according to claim 8 , wherein the low and high strain members are parallel to a longitudinal axis defined between centers of the motor and mounting rings.

10. The torque transducer according to claim 1 , wherein the mounting ring defines recesses configured to clock the mounting ring to the fixed structure.

11. The torque transducer according to claim 1 , wherein the body of the flex ring has inner and outer diameters, and wherein the inner and outer diameters determine a stiffness of the body.

12. The torque transducer according to claim 1 , wherein the strain gauge is positioned halfway between the first and second ends of the body of the flex ring.

13. An drive unit comprising:
a fixed structure;
a first motor having a drive shaft passing through the fixed structure; and
a first torque transducer positioned between the fixed structure and the first motor about the drive shaft of the first motor to mount the first motor to the fixed structure, the first torque transducer including:
a motor plate positioned about the drive shaft of the first motor and fixed to the first motor;
a mounting plate positioned about the drive shaft of the first motor and fixed to the fixed structure;
a flex ring positioned between the motor plate and the mounting plate and about the drive shaft of the first motor, the flex ring including a body having a first end and a second end that are moveable relative to one another, the first end of the body fixed to the motor plate and the second end of the body fixed to the mounting plate, the body configured to flex in response to the first and second ends moving with respect to one another; and
a strain gauge positioned on the body of the flex ring to measure flexation of the body.

14. The drive unit according to claim 13 , further comprising a first drive cable operably associated with the drive shaft and configured to manipulate a tool in response to rotation of the drive shaft.

15. The drive unit according to claim 14 , further comprising a converter coupled to the drive shaft of the first motor to convert rotation of the drive shaft into linear movement of the first drive cable.

16. The drive unit according to claim 13 , wherein the first motor is configured to manipulate a tool in a first degree of freedom.

17. The drive unit according to claim 16 , further comprising a second motor configured to manipulate the tool in a second degree of freedom different from the first degree of freedom, the second motor mounted to the fixed structure by a second torque transducer.

18. The drive unit according to claim 13 , wherein the fixed structure is an end of an arm of a robotic system.

19. A method of measuring a force exerted by a tool, the method comprising:
activating a motor of a drive unit to manipulate the tool, the motor mounted to a fixed structure of the drive unit by a torque transducer, the motor operatively associated with the tool to manipulate the tool;
measuring a reaction torque of the motor in response to activating the motor by measuring flexation of a body of a flex ring of the torque transducer; and
adjusting the energy supplied to the motor in response to the measured reaction torque of the motor.

20. The method according to claim 19 , wherein activating the motor of the drive unit includes supplying energy to the motor.

Assignees

• Covidien Lp

Inventors

• Allen Robert
• Seow Chi Min
• Zemlok Michael

Classifications

• H02P29/00

  Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors (arrangements for starting electric motors H02P1/00; arrangements for stopping or slowing electric motors H02P3/00; control of motors that can be connected to two or more different electric power supplies H02P4/00; regulating or controlling the speed or torque of two or more electric motors H02P5/00; vector control H02P21/00) · CPC title

• A61B2090/064

  for measuring force, pressure or mechanical tension · CPC title

• A61B34/30 Primary

  Surgical robots · CPC title

• A61B90/06 Primary

  Measuring instruments not otherwise provided for · CPC title

• H02K7/14

  Structural association with mechanical loads, e.g. with hand-held machine tools or fans (with fan or impeller for cooling the machine H02K9/06) · CPC title