Energy-regenerative Suspension Control Based On In-wheel Motored Vehicle

In order to realize more comfortable, convenient manipulation, safe, reliable andhuman constant pursuit of perfect performance, vehicle has been changed from the earlystage of complete mechanical to the current stage of combining variety of disciplinesand many new technologies, such as machinery, electronics, materials and control. Itsfunction becomes more and more powerful, and has much higher reliability. Now, it isdeveloping towards electric and intelligent vehicle. As a unique direction of thedevelopment of electric vehicles, wheel-drive system is considered to be the final driveform. However, due to its special form of drive, vehicle unsprung significantly increases,which affects not only the vehicle ride, but also reduces the driving safety. Nowadays,people are increasing requirements of the energy efficiency of electric vehicles, as wellas ride comfort and driving safety. So the in-wheel motor driver system which related tothe ride comfort, safety, handling and stability and its integrated control are become theresearch hot topic in the field of automobile engineering. Combing with the currentresearch status and the exist problems of in-wheel motored vehicle, center around theelectromagnetic energy-regenerative active suspension, from the view point of theoryanalysis of vehicle system dynamics in and abroad, this dissertation researched theeffect of in-wheel switched reluctance motor (SRM) on electric vehicle stability andcomfort, analysis energy conversion rules of electromagnetic suspension, modeling andcontrol active suspension to superess the effect of in-wheel mortor on vehicle stabilityand comfort.The main work of this dissertation including the following:①The relationship of different full vehicle attitudes and their effect to vehicleperformance have been analyzed. The union form Magic Formula tire model has beenchosen, a nonlinear coupling full vehicle model integrated in-wheel motor model andactive suspension system has been established. Preliminary analysis on vehicle andmotor characteristics has been discussed based on the full vehicle model. Then, theeffect of SRM on vehicle vibration has been researched, and the relationship of vehiclevelocity, rotor relative eccentricity and the vertical force of in-wheel motor has beenquantitative analyzed. The phase and frequency characteristic of in-wheel motor verticalforce has been determined. And the vehicle simulation model was built in theenvironment of Matlab/SIMULINK. Finally, the simulation model has been verified byreal vehicle test. ②Based on the study of the vertical force of switched reluctance motor andvehicle vibration modal analysis, the effect of motor vertical excitatiment on vehiclestability, comfort and energy regenerative has been discussed through RCF, tyre forceand vehicle vibration acceleration. To better reduce the damage of motor vertical forceeffect on vehicle stability and comfort, the concept of using energy regenerative activesuspension to deal with the new concerns was proposed. In addition, vehicle energyefficiency can be improved by the energy regenerative ability of suspension.③The energy regenerative characteristic of the vehicle electromagneticsuspension and self-powered magnetorhelogical suspension has been analyzed based onthe power flow. The calculation and analysis method of the energy conversionefficiency has been proposed. Based on the study of energy conversion efficiency, thecomparative work between the active system, passive system and the maximal outputpower system under level B and C road is made through computer simulation. And theself-desingend magnetorheological energy-regenerative semi-active suspension wasstudied through experiments.④The regenerate characteristics of active suspension under four different modehas been analyzed. Around basic energy regenerative problems of vehicle suspension,the effect of the energy regenerative on dynamics characteristic has been discussed. Thebasic problems as follows: the potential of energy regenerative, the key parameterseffect on energy regenerative characteristics, the relationship between eneryregenerative characteristics and velocity, road roughness and suspension dynamicscharactersitcs. Theoretical analysis of the index of energy regenerative evaluation hasbeen developed, which emphasis on suspension comfort, safety and energycharacteristics. Based on above discussion, the evaluation system of energy regenerativesuspension has been established. The relationship between suspension energyregenerative characteristics and suspension dynamics performance has beendeterminted.⑤The passive, semi-active, zero energyand active suspension work models havebeen analyzed. Then a main multi-objective control strategy was proposed whichcontrol the suspension to working in each model according to vehicle state,roadroughness and energy condition. In order to verify the effectiveness and correctness ofthe strategy, computer simulations have been conducted under four typical conditions.In the end, the study work of the whole paper was concluded. The characteristicsand the innovation of the whole paper were introduced. Besides, the problems that need deep study recently were pointed out.