Model-based adaptive hybrid control for manipulators under multiple geometric constraints

This paper proposes an adaptive hybrid controller for manipulators constrained on multiple smooth geometric surfaces and reports the experimental results on a six-degree-of-freedom direct-drive manipulator. This controller produces simultaneous position and force tracking of the constrained manipulators even when their physical parameters are unknown since it is incorporated with the model-based adaptive algorithm. The asymptotic stability is guaranteed by a passivity-based Lyapunov function. Further, we present a parallel implementation of this controller using transputers on the six-DOF manipulator. We examine the control performance by experiments of the manipulator in a point-point contact, two point-point contacts, and a face-face contact with the environment, respectively.