Active control of vibrations by low-pass filter and state feedback on a flexible structure

With a view to minimising the amplitude and duration of vibrations of a flexible beam, an active control system comprising a displacement sensor, digital compensation and a mechanical excitation system is studied. The results of the low-pass filter and the state feedback control laws are presented. The low-pass filter has been used to control the first vibrational mode and an original method of calculation is developed to evaluate the parameters of the filter as a function of the desired damping ratio on the structure. The results are confirmed experimentally by a physical set-up showing that highly satisfactory real-time vibration control can be achieved. Experimental results concerning active control by state feedback on the first two vibratory modes of the structure demonstrate that even better results can be obtained