Force-position-velocity control with self-tuning for robotic manipulators

The force-path control of a robotic manipulator is presented here in the joint and in the Cartesian coordinate systems. An autoregressive model with external excitation (ARX-model) is introduced for designing an adaptive controller with self-tuning. The controller minimizes the conditional expectation of the sum of a quadratic position (velocity) error and a quadratic force error while satisfying the constraint of the ARX-model with the estimates substituted for the unknown parameters. The basic approach is used to obtain an adaptive controller which operates on the variables expressed in the joint coordinates. Another adaptive controller is similarly determined for the system variables of the Cartesian coordinate system. The adaptive controller for force-path control introduced here has the form similar to that of hybrid force/position controller of [5], but with time varying gains.