Model reference adaptive control of a haptic feedback device for improving force performance

Abstract

In this paper, a new adaptive control algorithm of a haptic feedback device is analyzed. Forces applied to the haptic device through human hand movements are modeled as disturbances and compensated in the force control action. A model reference adaptive control (MRAC) scheme is proposed to improve force tracking performance. A separate reference model for every DOF is selected to satisfy rising time, settling time, peak time, and overshoot requirements. General adaptive control laws are developed for tuning gains in the control transfer functions based on the reference model and the force sensor and encoder readings in real time. These control gains cover force tracking performance and compensate human hand disturbances while providing robustness to sensor noise. Stability of the control system is shown analytically. Convergence and boundedness of control gains are also shown through experiments.