Acceleration Measurement-Based Disturbance Observer Control for a Belt-Drive Servo Instrumentation

Abstract

An acceleration measurement-based disturbance observer control method is proposed to capture and eliminate transient and dramatic dynamic disturbance torque in the flexible belt-drive servo instrumentation. The essence of this method is to incorporate the acceleration difference between the motor side and the load side to implement a disturbance observer (DOB) in the dual-rate control loop. The acceleration difference is sensitive to the rate variation caused by the motor-load large span distribution. The input signal of motor inner-loop with the high bandwidth is equivalently processed to obtain the estimated motor-side acceleration. However, the observed acceleration disturbance suffers from low-frequency drift and noise accumulation, resulting in the system instability under integral characteristics. Therefore the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> principle is used to ensure the stronger stability, and the compensator is bandpass-corrected to enhance the anti-disturbance performance in a limited bandwidth. The proposed method is experimentally validated to effectively suppress the disturbance torque after obtaining an optimal trade-off between robust stability and anti-disturbance. The error spikes and buffeting in the flexible transmission chain is further reduced compared with the conventional methods.