SURGICAL ROBOT AND CONTROL METHOD THEREOF

• US 20130116706A1
• Filed: 12/21/2012
• Published: 05/09/2013
• Est. Priority Date: 12/23/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: LEE, Kwang Kyu, Kwon, Woong, Roh, Kyung Shik
• Granted Patent: US 9,658,605 B2
• Time in Patent Office: Days
• US Class Current: 606/130
• 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 34/76 Manipulators having means for providing feel, e.g. force or tactile feedback
• CPC Class Codes: G05B 6/00 Internal feedback arrangements for obtaining particular characteristics, e.g. proportional, integral or differential

Abstract

A method for controlling a surgical robot includes calculating an external force acting on a robot arm mounted with a surgical instrument, filtering the external force acting on the robot arm when a central point of an incision is set, calculating a virtual force to enable the surgical instrument which is positioned away from the central point of the incision to return to the central point of the incision, and applying the calculated virtual force to the filtered external force, to control movement of the robot arm. As a result, it is possible to compactly design the surgical robot and thereby reduce the volume of the surgical robot.

Claims

1. A method for controlling a surgical robot comprising:

calculating an external force acting on a robot arm mounted with a surgical instrument;

filtering the external force acting on the robot arm, when a central point of an incision is set;

calculating a virtual force, to enable the surgical instrument deviating from the central point of the incision to return to the central point of the incision; and

applying the calculated virtual force to the filtered external force to control movement of the robot arm.

2. The method according to claim 1, wherein the control of movement of the robot arm is carried out in a manual positioning mode in which a user directly holds and moves the robot arm mounted with a surgical instrument by hand such that the surgical instrument is inserted through the incision and is positioned in a surgery site.

3. The method according to claim 1, wherein the calculation of the external force acting on the robot arm comprises:

detecting torque information acting on respective pivot joints constituting a joint part using a force/torque sensor; and

subtracting torque information of pivot joints corresponding to a torque value required for maintenance of a present position or movement of the robot arm without the external force being applied, from the detected torque information, to calculate torque information of pivot joints generated by the external force externally applied to the robot arm.

4. The method according to claim 3, wherein the filtering of the external force acting on the robot arm is carried out by removing torque information contributing to a deviation of a remote center of motion present on the surgical instrument from the central point of the incision, from torque information of the pivot joint generated by the external force externally applied to the robot arm.

5. The method according to claim 4, wherein the calculation of the virtual force comprises:

setting a virtual spring and a virtual damper between the central point of the incision and the remote center of motion;

calculating a deviation between the central point of the incision and the remote center of motion; and

calculating the virtual force using the calculated deviation, stiffness of the virtual spring and a coefficient of the virtual damper.

6. A surgical robot comprising:

a sensor to detect torque information acting on respective pivot joints constituting a joint part of a robot arm associated with an operation of the surgical robot;

an instrument adhered to the robot arm; and

a control unit to calculate an external force acting on a robot arm mounted with a surgical instrument, to filter an external force acting on the robot arm when a central point of an incision is set, to calculate a virtual force to enable the instrument which deviates away from the central point of the incision to return to the central point of the incision; and

to apply the calculated virtual force to the filtered external force to control movement of the robot arm.

7. The surgical robot according to claim 6, wherein the control unit controls movement of the robot arm in a manual positioning mode in which a user directly holds and moves the robot arm mounted with the instrument, by hand, such that the instrument is inserted through the incision and is positioned in a surgery site.

8. The surgical robot according to claim 7, wherein the control unit receives torque information acting on pivot joints constituting the joint part associated with the operation of the surgical robot, and subtracts torque information of pivot joints corresponding to a torque value required for maintenance of a present position or movement of the robot arm without an external force being applied, from the detected torque information, to calculate torque information of pivot joints generated by an external force externally applied to the robot arm.

9. The surgical robot according to claim 8, wherein the control unit filters the external force acting on the robot arm by removing torque information contributing to a deviation of a remote center of motion present on the surgical instrument from the central point of the incision, from torque information of the pivot joint generated by the external force externally applied to the robot arm.

10. The surgical robot according to claim 9, wherein the control unit sets a virtual spring and a virtual damper between the central point of the incision and the remote center of motion, calculates a deviation between the central point of the incision and the remote center of motion, and calculates the virtual force using the calculated deviation, stiffness of the virtual spring and a coefficient of the virtual damper, to calculate the virtual force.