Observer based robust control of an electric drive with a flexible coupling

A simple robust control method based on an observer with a multiple integrator plant model is investigated for a DC motor based drive with a flexible load. The problem of controlling the drive with unknown parameters and an external load torque is converted to the simple task of state control of the known plant model. The only information required for commissioning is the specified closed loop dynamics. In contrast with conventional drives, no adjustment of PI controller gains is needed. The method yields robustness with respect to model order uncertainty and this is demonstrated by applying the same controller for speed and position control. The simulations predict the intended robustness, including model order uncertainty, by indicating virtually identical closed loop dynamics without controller adjustment for speed and position control and very low sensitivity to step external load torques.