Design,Modeling And Test Of A Semi-active Inerter Featuring Magnetorheological Effect

Inerters are two-terminal mass elements in which the forces applied at the terminals are proportional to relative acceleration between the nodes.Inerter is completely corresponding to the capacitor based on the second mechanical-electronic analogies.The volume and weight of inerters are much smaller than those of any conventional mass element for the same force.Inerter enriches the structures and design of the vibration control system and promotes the development of mechanical network theory.The new vehicle ISD suspension system based on "Inerter-Spring-Damper"(ISD)has been extensively studied.A semi-active inerter featuring magnetorheological(MR)effect with tunable inertance is proposed,designed and investigated to enhance the performance of the passive inerters.The proposed MR semi-active inerter consists of a flywheel,a flywheel housing,a ball screw,a connection sleeve,bearings,upper and lower covers,excitation coils and MR fluids.MR fluids fulfilled in the flywheel housing of the MR semi-active inerter is energized by the excitation coils with applied current,and correspondingly the mechanical characteristics is tunable via the applied current.The mathematical model and the mechanical performance of the MR semi-active inerter is established and tested,respectively.The magnetic circuit characteristics of the MR semiactive inerter are analyzed and verified.The experimental results show that the output force of MR semi-active inerter increases with the increase of excitation current.Under the excitation current of 0–1.0 A,the inertance realizes the adjustment of 0–6000 kg.The nonlinear factors of MR semi-active inerter are analyzed based on experimental results and the nonlinear model of the SAI is further established.The preliminary principle verification of the continuous adjustment of the equivalent inertance of the SAI is conducted using the nonlinear model.Moreover,a compensator is proposed to address the problem of the phase difference and continuous inertance adjustment is realized.Finally,a quarter-vehicle ISD suspension model based on MR semi-active inerter is established and simulated.The simulation is based on comfort-oriented optimal inertance and optimal damping coefficient.The simulation results show that the performance of the body acceleration and suspension travel are significantly improved,and the performance of the tire dynamic load is improved under certain frequency.