Shock Waveform Iterative Learning Control of An Electro-hydraulic Shaking Table

The electro-hydraulic shaking table (EHST)is applied extensively in simulating the shock vibrations experienced by large-scale structures, by reproducing the shock waveform in the laboratory to assess the equipment's reliability. Three-variable-control (TVC) is frequently utilized for controlling EHST. However, the fluctuation of the frequency characteristics and unknown disturbance forces in the system are not compensated by TVC. The control precision of waveform reproduction cannot meet the requirement of the shock vibration test. An iterative learning control strategy for shock vibration is presented in this paper. Zero-phase error tracking control (ZPETC) is employed for compensating the fluctuation in system frequency characteristics. Iterative learning control (ILC) is developed for compensating the influence of disturbance forces. Experimental results of acceleration shock waveforms reproduction demonstrate the significant improvement in control precision for shock vibration tests achieved by the proposed method.