Research On Design And Vibration-Attenuation Performance Of A Magnetorheological Seat Suspension For Special Vehicles

The vehicle is a complex dynamic system.The ride vibration transmitted to the occupants of a moving vehicle significantly influences the comfort of the occupants and even threatens their health level.In particular,special vehicles work in severe conditions on rough roads and are exposed to serious vibration problem.Sustaining long-term high-intensity vibration may not only hurt the occupant's body,but also cause occupant's compound fatigue,which reduces occupant's vibration exposure time and affects vehicle's mobility and off-road capability.Therefore,reducing the vibration transmitted to occupants is a major problem.As a direct contact between occupant and vehicle,the seat suspension plays an important role in reducing the vibration transmitted to the occupant.The main work of this paper is to propose a magnetorheological(MR)seat suspension with variable stiffness and damping.The working mechanism and vibration-attenuation performance of the proposed seat suspension have been studied theoretically and experimentally.The specific work of this paper includes the following aspects:(1)The dynamic model of the MR seat suspension with variable stiffness and damping is proposed.The transfer function,the equivalent stiffness and the equivalent damping of the seat suspension are presented.Then the influences of seat parameters on the equivalent stiffness,the equivalent damping and the transfer characteristics of the seat suspension are studied.(2)The overall structure of the MR seat suspension and the structure of the MR damper are designed.The magnetic circuit inside the MR damper is simulated by Comsol.Subsequently,the MR damper is manufactured and tested.According to the test result of MR damper,a force-predicted model of MR damper is established by using Bingham model and improved Sigmoid model.(3)The road profile of random road and the dynamic model of MR seat suspension are established.The principle of sky-hook(SH)control strategy is expounded.The acceleration signal is used instead of the velocity signal,and a fuzzy logic control strategy for the proposed MR seat suspension is presented.The control system is simulated based on SH controllers and fuzzy controllers by adopting Matlab/Simulink,and the simulated results are compared and evaluated.(4)The control system of the magnetorheological seat suspension is designed and implemented.The vibration isolation test of the proposed seat suspension is built based on the vibration table.The vibration-attenuation performance of the seat suspension is studied by the harmonic excitation signal and the random excitation signal respectively.