Swing Servo Control Based on Extended Kalman Filter With Disturbance-rejection

Large inertia direct drive system often needs high gain controller to realize high response servo control, and the rotor position sensor of motor is generally used to process the rotor position through the phase-locked loop and filter to obtain the speed feedback. The high bandwidth of conventional filter is easy to introduce speed noise, which affects the control stability, Also, the low bandwidth filter limits the control response of the system. First, the extended Kalman filter (EKF) based on the rocker motion model is used to observe the motor speed in this paper. This method not only avoids the signal noise, but also is convenient to support the model-based motion control method to obtain high control response. However, the model parameters change greatly in the actual motion, such as the values of motion damping and motor torque constant at different rocker arm positions, which are quite different, so the conventional EKF is highly dependent on the parameters. In order to solve this problem, this paper introduces the anti-interference compensation mechanism. By comparing the deviation between the EKF position estimation and the actual rotor position measurement, the disturbance caused by the change of motion parameters can be obtained. By compensating the disturbance, the velocity observation error caused by parameter change can be suppressed. Furthermore, this paper uses model predictive control (MPC) to further improve the dynamic performance of the system. Finally, this paper studies the proposed strategy through simulation, and the effectiveness of proposed scheme can be proved through the rocker arm servo test-bed based on permanent magnet synchronous motors (PMSM). © 2023 Chinese Society for Electrical Engineering. All rights reserved.