Measuring method for the torque control of instrument in surgical robot

The surgical robot instruments conduct an operation in the body on behalf of the surgeon´s hands. However working inside a body prohibits attaching electronic sensors in addition to space restriction. Therefore, all commercial surgical robots are only operated in position control mode becuase there is no way to measure the working force at instrument. The position control mode of the robot system has some problem in grasping. To build a force controllable surgical robot instrument system, this paper proposes torque measuring mechanism indirectly using reaction force. The proposed mechanism estimates the grasping force from measuring reaction force against the driving motor by using a load-cell. The motor is mounted on movable platform which push on load cell according to the tension arisen by reaction force.