A CONTROL SCHEME BASED ON ER-MATERIALS FOR VIBRATION ATTENUATION OF DYNAMICAL-SYSTEMS

Based on a bang-bang control scheme acting on so called ''electrorheol ogical'' fluids (ER-fluids), a vibration suppression method is propose d for a class of n-dimensional systems subjected to unknown perturbati ons. The proposed controller relates to robustness vis-a-vis unknown b ut bounded disturbances. Two approaches for designing the control sche me are presented and compared. On the one hand we employ Lyapunov stab ility theory; on the other hand there is an obvious reason for minimiz ing rate of energy change due to the spring/damper elements by varying the ER-fluid properties appropriately. The system under investigation is an n-degree of freedom one consisting of masses and spring/damper elements. The spring/damper elements contain an ER-fluid; their stiffn ess and damping properties are changed by varying an imposed electrica l field. The changes in spring and damping properties can be effected in microseconds since the control does not involve the separate dynami cs (inertia) of usual actuators. Detailed derivations are presented fo r a two-dimensional case and simulations are carried out for examples of smooth periodic and discontinuous periodic excitation forces.