Abstract:

Nonlinear control methods for friction compensation are proposed to improve the precision of position control of ball and plate system. Friction forces are estimated by a nonlinear state observer constructed in an augmented space. A stabilizing position controller with friction compensation is designed using the methods of input/output precise feedback linearization and optimal theory. A position tracking controller, which eliminates the influence of friction, is designed with the theory of variable structure control. Simulation shows that the proposed nonlinear control methods for friction compensation are feasible. Stabilizing control experiments prove that the proposed methods can significantly reduce the position errors in steady state. Tracking control experiments prove that the proposed methods can significantly improve the tracking accuracy.

Key words: automatic control technology, friction compensation, nonlinear control, state observer, ball and plate system, extended Kalman filter