Self-tuning feedforward control for active vibration isolation of precision machines

A novel feedforward control strategy is presented to isolate precision machinery from broadband floor vibrations. The control strategy aims at limiting the low-frequency controller gain, to prevent drift and actuator saturation, while still obtaining optimal vibration isolation performance at higher frequencies. This is achieved by limiting the low-frequency control action such that almost no phase shift is introduced at higher frequencies. To minimize model uncertainties, the feedforward controller is implemented as a self-tuning IIR filter that estimates the parameters online. Only a few parameters have to be estimated, which makes the algorithm computationally efficient. An additional feedback controller is designed to make the self-tuning algorithm more robust. The effects of feedforward and feedback control add up. The control strategy is successfully validated on an experimental setup of a vibration isolator.