Impact of excitation signal upon the acceleration harmonic distortion of an electro-hydraulic shaking table

The shaking table is an important experimental apparatus for mechanical environment tests. This work is focused on an electro-hydraulic shaking table, which has a single degree of freedom. Its configuration and working principle are described. A three-variable controller composed of feed-forward and feedback is applied to achieve iso-acceleration control. The acceleration excitation signal is filtered by an input filter to obtain input variables for the three-variable controller. From the sinusoidal shaking results, harmonic distortion exists in the acceleration response. The frequencies of harmonics are integer multiples of the fundamental frequency. Different harmonic distortion and harmonic distribution occur in the acceleration response excited by different acceleration excitation signals. The acceleration harmonic distortion is decreased as the amplitude and frequency of the excitation signal are increased.