Extension of sliding control theory to the model-independent active vibration damping of flexible structures
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A control methodology integrating sliding mode control, distributed parameter systems theory, and fuzzy logic is developed for the vibration damping of flexible structures. The method reduces the theoretically infinite-order plant to a second-order input/output representation, capturing its vibratory nature in a series of decentralized input/output loops. A sliding controller is then designed for vibration damping, where the equivalent control input is derived using no a priori temporal model of the plant dynamics. A fuzzy logic gain weighting is employed for the switching portion of the control to increase performance off the sliding surface, and to preclude control spillover into higher modes. Simulations results are presented for the active damping of a piezoelectric transducer-augmented cantilever beam. The fuzzy/sliding-mode controller demonstrates superior damping performance and robustness compared to an LQG/LTR model-based compensator for equal maximum control amplitudes. The LQG/LTR compensator is destabilized by only a 2.5% variation in the plant natural frequencies. The sliding mode controller maintains a 5 times better settling time performance, and closed-loop stability, even in the presence of 20% variations in the beam natural frequencies.
author list (cited authors)
Meyer, J. E., Burke, S. E., & Hubbard, J. E.