Input Delay Control of Pneumatic Vibration Isolation Table

Pneumatic isolators are promising candidates for increasing the quality of the precision instruments. For this purpose, however, higher performance of such isolators is a prerequisite. In this paper an adaptive fuzzy sliding mode controller is proposed and applied to a pneumatic isolator to enhance the isolation performance in the low frequency range, i.e., where the passive techniques have obvious shortcomings. The main idea is to combine the well-known time delay control technique with an adaptive fuzzy predictor. The adaptive fuzzy sliding mode control and the adaptive fuzzy predictor help to circumvent the input delay and nonlinearities in such isolators. The main advantage of the proposed method is that the closed-loop system stability is guaranteed under certain conditions. Simulation results are compared to the experimental measurements of the implemented TDC technique to verify the effectiveness of the proposed method.