Robust position control of a transportation carriage directly driven by a linear brushless d.c. motor

Abstract

This study proposes robust position regulation and output tracking controllers for a transportation carriage directly driven by a linear brushless d.c. motor. System identification for the linear motor and driver is performed using a dynamic signal analyser, thus providing a linearized model for the system. According to the selected nominal parameters, an optimal linear quadratic solution with a prescribed degree of stability is obtained. Owing to inaccuracies in the identification procedures and possible payload variations, system parameter uncertainties exist. In addition, time-varying disturbances corrupting the motor driver are also considered. Thus, an auxiliary input, connected to the nominal optimal control, is introduced to guarantee robustness for the control of the transportation carriage. Computer simulation and experimental implementation are completed and compared. These results demonstrate the effectiveness of the proposed approach for the position regulation and output tracking control within the linear brushless d.c. motor and also confirm the feasibility of its implementation in manufacturing systems.