Position Control of Servo Drive With a State Observer

The paper is dedicated to the design and comparison of a positional servo drive with two alternative control structures. PD controller and a state observer are used in two model based control approaches, which differ in type of the state observer. One of them contains an inverse plant model combined with filters of the position and velocity feedback (DO-FPID control). Their orders are optional. The second structure includes an extended state observer (ESO) combined again with filters in the position and velocity feedback. However, the filter orders are not optional and follow from the ESO structure (ESO-PID control). In addition, in both structures a setpoint feedforward is utilized. Its purpose is to minimize the control error during continuous position reference changes. Tuning of the controller, state observer and feedforward parameters are presented in the paper. Properties of the considered position controllers are verified through simulation.