A Practical Adaptive Sinusoidal Vibration Control Strategy for Electro-Hydraulic Shake Table

Background: The electro-hydraulic shake table (EHST) is an essential equipment for vibration tests. When performing sinusoidal vibration excitation, the acceleration response suffers from amplitude attenuation, phase delay, and harmonic distortion, which reduces the accuracy of the vibration test. Purpose: The filtered-x least mean square (FxLMS) algorithm has been generally implemented for narrowband vibration control. However, for the application of vibration realization with an electro-hydraulic shake table, potential instability caused by model identification errors and variations in system characteristics needs to be handled. Method: A practical adaptive sinusoidal vibration control strategy for the EHST combining FxLMS algorithm and online model error compensation technique is proposed in this paper. The control strategy uses auxiliary filters and the simultaneous equation method to achieve online model error compensation. To reduce the computational burden, the local model is adopted for the implementation of the proposed controller. Results: The feasibility of the proposed control strategy is verified with numerical simulation. The influence of parameters on vibration control precision and dynamic characteristics is investigated in detail. Sinusoidal vibration realization experiments are conducted using an EHST, and the experimental results verified the accuracy of the proposed control strategy. Conclusion: The proposed modified narrowband FxLMS with online model error compensation improves the stability and convergence when considering the system identificaiton error. The proposed practical sinusoidal vibration control strategy improves the vibraion realization performance of the EHST.