A passivity-based force/position control scheme for robot manipulators

The problem of designing a control scheme for robot manipulators in contact with a compliant surface is considered. A passivity-based force/position control scheme is designed. A keen choice of the reference vector used in the control law is proposed as a function of the end-effector position and velocity errors and the integral of the contact force error. It is demonstrated that the scheme ensures tracking of the unconstrained components of the desired end-effector trajectory with regulation of the desired contact force along the constrained direction. In the imperfect model compensation case, the scheme is made adaptive with respect to a set of dynamic parameters. Numerical case studies are presented for an industrial robot manipulator