A simple and novel control strategy for semi-active vibration suppression by a magnetorheological damper

Conventional skyhook-based ON–OFF control switches the damping force on a vibration suppression target according to the sign of the product of the target and relative velocities (which is called the condition function). Here, we propose a control strategy that uses a novel condition function for improved performance. The proposed strategy is formulated based on the theory of forced vibration with base excitation. Its effect upon semi-active vibration performance is investigated via numerical simulations and experimental tests of the vibration suppression of a small structure equipped with a magnetorheological (MR) damper. In the simulations, the proposed control strategy can offer high-performance semi-active vibration suppression, even in the presence of force delays in the damper. The experiments show that the displacement response with the proposed control is lower than that with the conventional skyhook-based control over the entire frequency range; furthermore, the desired performance can be achieved when the proposed condition function is used with velocity-proportional control. The simplicity and high performance demonstrated by the proposed control strategy make it applicable to semi-active vibration suppression of practical systems, even in the presence of unavoidable force delays in controllable dampers.