The Vibration Characteristics Research Of In-wheel Motor Driving Vehicle Based On The Energy Analysis

With the continuous consumption of energy and environmental problems gradually highlighted,electric vehicles have become an important trend in the automotive industry.In the study of electric vehicle,the in-wheel motor drive vehicles(IWMDV)is favored by people in the industry because of its unique advantages such as space saving,high efficiency and flexible control.However,due to the special drive form of IWMDV,the vertical vibration of the vehicle is deteriorated significantly.Because the motor is integrated in the wheel hub,the unsprung mass of the vehicle is increased,the unsprung structure is changed,and the motor excitation also has some influence on the vibration of the vehicle.Therefore,this paper will analyze the vibration problems,in order to get a better structure of in-wheel motor and reasonable damping measures,so that the IWMDV vibration problems can be improved.The main contents of this paper are as follows:(1)Establishment and verification of the vibration model of IWMDV based on the bond graph method.Taking an rear wheel drive in-motor vehicle as the research object,the IWMDV vibration model is simplified as 1/2 IWMDV vibration model,established the mathematical model of the model based on bond graph method,verify the correctness of the mathematical model by the method,lay the foundation for the subsequent analysis of IWMDV vibration characteristics.(2)Analysis of vibration characteristics of IWMDV.The natural frequency of the vibration model of 1/2 IWMDV is analyzed by using the bond graph method,to study the basic characteristics of the vehicle vibration under the new structure.Then,based on the idea of the vibration energy transmission of the vehicle,the vibration characteristics of IWMDV under multiple excitation of is analyzed,and the influence of vehicle parameters on the vibration energy transmission of the vehicle is analyzed,so the influence of the vehicle parameters change on the vibration energy of the vehicle is obtained,which lays the foundation for further improvement and optimization of IWMDV structure.(3)Improvement and optimization of IWMDV structure.According to the analysis results of the vibration characteristics of IWMDV,two kinds of in-wheel motor improvement structures are proposed,the vehicle vibration models of the two improved in-wheel motor structures are established,and two kinds of improved structure vehicles are analyzed and compared by the bond graph modeling and simulation.Combined with the analysis of the results and the actual situation,the improved structure 2 is selected as the final improvement plan.On this basis,as trasmmit to the body before and after A,B two points of the sum of the vibration energy for the optimization target,genetic algorithm is used to optimize the vehicle parameters of the improved structure 2,and the vehicle vibration characteristics are simulated and compared before and after the optimization,the results show that the optimized vehicle parameters makes the vibration of IWMDV be further improved.(4)Study on the vibration control of IWMDV.The fuzzy PID control is used to study the vibration control of the suspension system of IWMDV.Based on the optimized vehicle of the improved structure 2 before,first as trasmmit to the body before and after A,B two points of the sum of the vibration energy for the optimization target,the initial parameters of the PID controller are obtained by genetic algorithm,and then the fuzzy PID controller model of the vehicle suspension system is established.Finally,the vibration characteristics of IWMDV before the control and the vibration characteristics of IWMDV after fuzzy PID control are compared and analyzed.The result shows that the established fuzzy PID controller effectively improves the vibration characteristics of IWMDV.