Adaptive inverse control of time waveform replication for electrohydraulic shaking table

A combined control strategy with an adaptive inverse control (AIC) and an inverse frequency response function (IFRF) equalization technique is proposed for the electrohydraulic shaking table (EST) system. The control purpose is to improve the accuracy of time waveform replication. In contrast to the iterative compensation through repetitive excitations control approach of industrial EST controllers, the proposed control strategy utilizes an IFRF of the EST system for extending the EST system frequency bandwidth and obtaining asymptotic reference tracking, and employs a variable tap-length filtered-x least-mean-squares algorithm to adaptively tune the time-domain drive signal and further improve the position and acceleration tracking performance of the EST system. Thus, the proposed combined control strategy is designed to combine the merits of IFRF and AIC. The procedures of the proposed control strategy are programmed in MATLAB/Simulink, and then compiled to a real-time PC with Microsoft Visual Studio.NET for implementation. The simulated and experimental results show that this control strategy achieves satisfactory position and acceleration waveform replication accuracy.