Forced dynamics position control of the drive with flexible coupling and load position measurement

Paper presents a position control system capable of achieving the prescribed speed and position response, for drives with PMSM and a significant vibration mode. The controller is of cascade structure, comprising an inner speed control loop and an outer position control loop. The inner speed control system complies with principles of vector control and feedback linearisation. The outer position loop based on `forced dynamics´, controls the load angle in the presence of flexible coupling and external load torques. A set of two observers, the first on the load side, and second on the motor side, generates all the state variables necessary for speed and position control algorithms with prescribed dynamics. This approach allows elimination of the motor side position sensor. Simulations confirm that the proposed model based control system with one position sensor can operate with moderate accuracy.