Recommended control configurations for DC drives with flexible shafts

This paper deals with new recommended control structures for adjustable speed DC drives with flexible coupling. Due to lack of space, the two-inertia system i.e. single motor driving a load through an elastic coupling (e.g., section fan drive) is only analyzed. The first recommended control configuration is an extension of the rigid system controller with an added control term that is proportional to the differential speed. The second recommended configuration is the variable structure sliding-mode control (VSC) which is known to be robust, insensitive to parameter variations, and easy to implement. Simulation results are presented to illustrate the effectiveness of the proposed controllers