Abstract:Aiming at the problem that the increase of unsprung mass of electric vehicle driven by wheel motor results in the intensification of vertical vibration of vehicle, two suspension system including motor suspension devices, multi-stage vibration isolation(MVI) type and dynamic vibration absorption(DVA) type were designed, and the corresponding mathematical models of vehicle vertical vibration were established. The hub motor suspension stiffness and damping were regarded as optimization variables, the displacement and boundary constraints were determined and a multi-objective optimization function was established. MATLAB software was used to establish the simulation model, based on the analysis of the motor suspension stiffness and damping of suspension system, body acceleration, dynamic deflection of body suspension, dynamic deflection of motor suspension and root mean square value of tire dynamic load were used as evaluation indexes to compare vehicle ride comfort of multi-stage vibration isolation type and dynamic vibration absorption type hub motor suspension system configuration. The results show that the stiffness and damping optimization results of multi-stage vibration isolation type and dynamic vibration absorption type are 119 880 N/m and 200 N〖KG-*2〗·〖KG-*4〗s/m, 9 995 N/m and 1 296 N〖KG-*2〗·〖KG-*4〗s/m, respectively; compared with the multi-level vibration isolation hub motor suspension system, the dynamic vibration absorption type can better improve the negative effect of vertical vibration of vehicles and improve the comfort of vehicles.