Magnetically leviated fine motion wrist: Design and feasibility experiments

For a large class of micromechanical assembly tasks requiring compliant motion, it is unnecessary and indeed impossible to provide the needed compliance in the robot manipulator. Instead, active compliance over a limited range of positions can be achieved by dividing a robot manipulator system into coarse and fine domains. The coarse manipulator provides gross positioning capability, while the fine motion wrist provides precise, compliant motion. This paper describes a high performance six degree-of-freedom magnetically levitated fine motion wrist with programmable compliance. Design considerations, and discussion of the actuators, sensors and structure are presented. A prototype wrist has been built and controlled in both position and compliance modes.