An experimental validation of flexible actuator with torque wire for haptic motion

A flexible actuator is a system applied release mechanism to separate an end-effector and a motor. That is for weight saving and miniaturization of robotic end-effector that are demanded in surgical robots especially. The flexible actuator has stiffness and flexibility. Therefore it transmits force input from the motor to the end-effector, and puts the end-effector on any position against the motor. Then flexible actuator can be used with bilateral control. With bilateral control, it can transmit force sensation from the end-effector contacting environment to operators. In this paper, a torque wire for transmission of rotation and torque is developed, and the characteristics of position/torque transmission are validated. Steady-state error is caused between the motor input and the end-effector response. The error is due to elastic torque of the torque wire as well as frictional torque between an inner wire and an outer tube. The end-effector response corresponds to the motor input. Then, availability of the torque wire is confirmed.