On the stability of adaptive controllers for robotic manipulators

The design of an adaptive force and position control system with adjustable gains for robotic manipulators is presented. The design is based on a hybrid feedforward-feedback architecture. The force control module is developed in a feedforward loop and is governed by a control law which includes time-dependent proportional, integral and derivative gains. The position control module is developed in a feedback loop and is governed by a linear adaptive control law which include position, velocity, and acceleration gains. The control gains are continually adapted according to well-defined adaptation schemes formulated to minimize force and position error signals, respectively. Stability considerations in the sense of Lyapunov are formulated, and an outline of a proposed simulation scheme is presented