APPROXIMATE TIME-OPTIMAL CONTROL OF DC SERVOS WITH UNKNOWN LOAD AND NONLINEAR FRICTION TORQUE

In this paper we apply the minimum time optimal control strategy to achieve the fastest possible position tracking of a servo system under unknown load and non-linear friction torque. Adaptive identification of the discretized model, which becomes a non-linear function of the unknown parameters, is implemented under poor excitation of bang-bang control by introducing two approximate methods. The results show significant improvement in the performance of the system.