Research On Engine Mount Control Based On Active Vibration Isolation

Engine as the vibration source of the whole vehicle will directly result in the aggravation of vibration noise in the whole vehicle.Mount as a connecting component between the engine and motor-vehicle chassis,its vibration isolation effect will influence the stabilization of the whole vehicle and determine the vehicle's service life.Currently,most automobiles use passive rubber mount,which can reduce the low-frequency vibration of the engine but cannot improve its high-frequency vibration.Based on the limitation of passive mount,active engine mount constituted by intelligent materials appeared and solved this difficult problem.This paper first discussed the mechanical properties of the piezoelectric material,deduced the relationship between the active control force and the input voltage,and verified the theory by the experimental method.Secondly,the kinetics model of idling three degree-of-freedom active mount with engine three-dimensional excitation force as input,the kinetics model of five degree-of-freedom active mount with roadway unevenness and engine's vertical excitation force as input,and the kinetics model of ten degree-of-freedom vehicle's active mount with roadway unevenness and engine's three-dimensional excitation force as input have been established.According to the input of the system,the road model is established and the composition of the engine excitation is analyzed.Thirdly,based on the analysis on engine vibration source,according to the condition of engine vibration,an active mount control system is designed with engine vertical,rolling and pitching speed and accelerated speed as the input of three fuzzy controllers,with active control force as the control output,to distribute to engine's four mounts through logic controller.Research result indicates that,compared with passive mount system,fuzzy control based active mount system can improve the vibration isolation capacity of engine.Meanwhile,engine three-degree-of-freedom fuzzy control will be used as the outer-loop control of vehicle engine active mount system in the following text.Its major function is to control engine three-dimensional excitation.Fourth,based on five-degree-of-freedom engine active mount system model,propose to use Single Input Rule Modules fuzzy reasoning(SIRMs fuzzy reasoning),and apply it to five-degree-of-freedom engine active mount.Research result indicates that compared with classic fuzzy control,SIRMs fuzzy control can better restrain vibration in the engineand vehicle body.Its algorithm is simple and feasible.Meanwhile,use SIRMs fuzzy control as the inner-loop control of vehicle engine active mount system in the following text.Its main function is to control roadway unevenness and engine's vertical excitation.Finally,based on excitation sources of vehicle(roadway unevenness and engine excitation),active mount classic fuzzy controller and active mount double-loop controller are respectively designed.At the same time,conduct simulation on bulged roadways and random roadways.Simulation result shows that vehicle's double-loop controller can better improve vehicle's riding comfort and it has stronger adaptability and robustness.