Observer-based automatic control loop tuning for servo motor drives

Accurate servo drive tuning requires motor electrical and mechanical parameters such as torque constant, moment of inertia, and frictional torque coefficient. In this paper, an observer-based auto-tuning scheme for servo motor drives is presented. The main element in this scheme is a state estimator which generates a motor parameter-related disturbance torque. Following the disturbance estimator, two adaptive controllers are used to adjust the drive inertia and frictional torque to their correct values. The servo control loops are tuned automatically with the parameters identified. Motor torque constant is also identified and used in the disturbance estimator. The experimental results verified that the proposed scheme can accurately identify motor parameters and tune the servo control loops.