Selective Backdriveability and Its Application to a Robotic Finger Design

The work reported covers the design of a prototype finger unit which will be part of a dexterous robotic hand design. Unlike conventional designs for contemporary hands which use tendons to actuate individual finger joints, this design uses small electric motors located in the finger units themselves. Because of high gear ratios in the final drive, the finger is able to sustain a grasp with power removed. An implementation of compliant joint control is discussed, and it is shown that this results in an actuation system which not only has variable stiffness control, but one in which the systems inability to be backdriven may be eliminated for those tasks where it is advantageous to do so.