| At present,the powertrain vibration isolation generally uses rubber mount or ordinary hydraulic mount,but the traditional mount can only be isolated within a certain frequency range,can not play a good isolation effect in the full frequency range.The MR(magnetorheological)mount has been studied because of its characteristics of adjustable damping force,low energy consumption and fast response.In order to explore the effect of the MR mount on vibration isolation of powertrain of hybrid electric vehicle,the dynamic characteristics of the MR mount based on ordinary hydraulic mount were studied.A half-car six-degree of freedom model of the MR mount system for hybrid electric vehicle powertrain was established,and a simulation model was designed for vibration isolation of powertrain by fuzzy control strategy,ceiling control strategy,traditional PID control strategy and SOA algorithm.The research work and conclusions of this paper are as follows:The rheological characteristics and working mode of the MR fluid are introduced in detail.The internal structure of a hydraulic mount was redesigned based on the extrusion flow mode.The designed MR suspended magnetic circuit structure was theoretically analyzed by electromagnetic field theory,and MAXWELL software was used to conduct magnetic field analysis on the magnetic circuit structure to verify whether the designed magnetic circuit meets the strength requirements.The mechanical model is established based on the designed MR mount structure.By fitting the calculated data points of the output controllable damping force and the control current of the MR mount,the third-order curve relation between the controllable damping force and the control current is obtained,which provides theoretical support for the control of the MR mount.MATLAB/SIMULINK simulation software was used to establish the simulation model of the MR mount dynamics formula.The restoring force performance curves of the MR mount under different currents and excitation frequencies and the dynamic characteristics of the MR mount under different electric currents and varying frequencies can be obtained.Simulation results show that the designed MR mount has good vibration isolation effect.To verify the vibration isolation effect of the MR mount system for powertrain of hybrid electric vehicle.The vibration excitation of single-cylinder engine and four-cylinder engine is analyzed,and the vibration excitation generated by electromagnetic force in the driving motor is described in detail.A dynamic model of the six degree of the freedom MR mount system for half car was established considering the influence of both powertrain excitation and road excitation.SIMULINK was used to simulate the six degree of freedom MR mount system of hybrid electric vehicle.Based on the principles of fuzzy control,canopy control and PID control,the controller simulation model of the MR mount system of half car power train with six degrees of freedom is designed by fuzzy control,canopy control and traditional PID control.In order to achieve efficient vibration reduction,an SOA optimization algorithm is introduced to optimize the PID parameters.Simulation results show that the PID control based on SOA optimization algorithm can effectively achieve the purpose of vibration isolation. |
