Globally stable compliant motion control for robotic assembly

The robust compliant-motion approach yields a controller which causes the manipulator to exhibit a specified mechanical impedance in a small region, but does not ensure stability elsewhere. Design criteria are presented, consisting of three matrix equations to be satisfied by position, velocity, and sensor input gain matrices, which yield a globally stable controller meeting a target impedance specification near a specified operating point. Three methods of solving these equations are proposed, one of which is illustrated by an example. It is shown how the approach may be extended to redundant manipulators