Research on Acceleration Harmonic Cancellation of Electro-hydraulic Servo Shaking Table

• 1、College of Mechanical and Electrical Engineering, Harbin Engineering University
• 2、School of Mechanical and Electrical Engineering, Harbin Institute of Technology

Abstract：Nonlinearities are inherent in electro-hydraulic servo shaking table. Some nonlinearities are dead-zone of servo valve, backlash and friction between joints, and friction in hydraulic cylinder. Nonlinearities cause harmonic distortion of the output acceleration signal corresponding to a sinusoidal input. Based on extensive studies on literatures related to dead-zone, backlash and friction compensation scheme, the method for harmonic cancellation based on adaptive notch filter technology is developed. The task is accomplished by generating reference signals with frequency that should be eliminated from the output. According to the error between the input acceleration and the feedback acceleration, the weights of filter are adjusted on-line by LMS adaptive filtering algorithm in real-time. The reference inputs are weighted by the adaptive filter in such a way that it closely matches the harmonic. The output of the adaptive filter is a harmonic replica and is injected to the fundamental signal such that the output harmonic is cancelled, and the total harmonic distortion (THD) is greatly reduced. The above course is used as a basis for the development of adaptive harmonic cancellation (AHC) algorithm.

Keywords： Dead-zone Backlash Friction Harmonic Cancellation Adaptive Filtering Algorithm