Vibration control of the seat suspension with a magnetorheological damper-based controllable inerter

Semi-active devices have been extensively studied for seat suspension to improve passenger riding experience. However, the traditional semi-active devices can only control the amplitude of the generated force and cannot change the direction of the force as needed. This paper proposes a vibration control method for a new seat suspension with a magnetorheological (MR) damper-based controllable inerter (MRDCI) to break the performance bottleneck of the traditional semi-active seat suspension. The MRDCI consists of two MR dampers, two sets of rack and pinion, and a flywheel. The device can convert reciprocating vibration into unidirectional shaft rotation, and the flywheel can release stored energy to generate a controllable force for vibration reduction. It can work as a controllable inerter. Then, a semi-active controller for the seat suspension is designed for vibration control, and it includes a sliding mode controller that calculates the desired control force and a semi-active control strategy for the control of MRDCI to track the desired control force. Finally, experimental tests are conducted to verify the vibration control performance of the suspension. The results show that the new suspension performs better than the traditional passive and semi-active variable damping (VD) suspensions. Under road excitation, the proposed seat suspension’s RMS acceleration and FW-RMS acceleration are reduced by 9.38% and 15.8% compared to the traditional semi-active VD seat suspension.