Variable damping impedance control of a bilateral telerobotic system

Stiffness and damping control in a telerobotic system allows the master and slave dynamics to be defined by the user. However, many requirements for good teleoperation produce conflicting choices of desired dynamic parameters. Rather than selecting a compromise value for the damping of the master and slave, it is proposed that these values be functionally dependent on sensed and commanded values of force and velocity, with no previous knowledge of the environment required. A strategy is proposed which provides better quality teleoperation under a variety of circumstances than is achievable with constant dynamics. It is shown that tracking in free space and along a surface by the slave can be maintained while impact forces are minimized. The algorithms have been implemented on a 7-DOF Robotics Research Corporation manipulator with a 6-DOF Kraft master hand controller, and the impact and tracking performance is illustrated