Control Algorithm Design of the Active Pneumatic Vibration Isolator

The background for the proposed vibration isolation method is based on the principle of active pressure control, minimizing the cyclic load transmitted to the system base through elastic pneumatic element. The paper presents a research on effectiveness of PID-control algorithm with back-calculation of integrator part. Pressure pulsation inside the pneumatic element of the vibration isolator is studied in the frequency range that includes its sub-resonant and resonant frequencies. Spectral analysis is conducted in order to analyze the harmonic excitation response of an active pneumatic isolation system and a passive one, with disabled valves control. The minimal bore size and response rate of the control valve are defined to achieve at least a double advantage of the active system over the passive one in the frequency range including the vibration isolator resonant frequency. As expected, the proposed control algorithm demonstrated a decent decrease of pressure pulsation amplitude at a low frequency range of a Hertz-level excitation signal. The calculation data analysis shows that PID-control algorithm with back-calculation of integrator part can be effectively used for active pneumatic vibration isolator, if the control valve parameters are within specified ranges.