| The purpose of this study is to investigate the magnetorheological (MR) fluids, MR fluid actuators, and control laws for their use in the structural vibration control applications. This study shows that the proper semi-active control laws, which dissipate energy in the system for part of the vibration cycle, allow an MR fluid actuator to provide excellent structural vibration control performance with low power consumption.; The test rig used in this work is a simply supported beam excited by a harmonic disturbance. An MR fluid actuator is used to control vibrations in the beam. It is shown that the best vibration reduction is achieved by leaving the MR fluid actuator on all the time. However, almost the same vibration reduction can be accomplished with semi-active control laws (switching the actuator on and off) with significant energy savings. This is first shown, through experimental testing and numerical simulations, with two heuristic semi-active control laws. A Lyapunov approach is then used to develop more rigorous control laws based on the energy level or rate of energy change in the system. These new control laws are tested to show that a beneficial tradeoff between vibration control performance and energy consumption can be achieved. Finally, a new test rig is developed and tested wherein the MR fluid actuator is implemented in an imbedded arrangement. |
