Simulation of magneto-rheological semi-active suspension system of EV driven by in-wheel motor

Transcription

1 rd International onferene on Mehatronis, Robotis and Autoation IMRA 5 iulation of agneto-rheologial sei-ative suspension syste of EV driven by in-wheel otor huanglong Zhu, a,hailu Tang, b hool of Autootive Engineering,Wuhan University of Tehnology,Wuhan Hubei 47,hina a solezsl@6.o, b 748.qq.o Keywords:EV driven by in-wheel otor;/4 vehile odel;magneto-rheologial sei-ative suspension syste; Multi degree of freedo. Abstrat. ei-ative ontrol of vehile suspension syste an be realized by adopting the agneto-rheologial daper. This paper does researh on EV driven by in-wheel otor,whih adopts the otor suspension devie and the agneto-rheologial sei-ative suspension. Based on the vehile dynais theory, the three degrees of freedo odel of /4 vehile with agneto-rheologial sei-ative suspension and passive suspension are established respetively. Then the MATLAB/iulin is used to siulate the two inds of suspension systes. The agneto-rheologial sei-ative suspension adopts the "y-hoo" ontrol strategy. The siulation results show the advantages of agneto-rheologial sei-ative suspension. This paper provides a referene ethod for siulation with ulti degree of freedo vibration syste eanwhile. Introdution EV driven by in-wheel otor is a new eletri vehile, and the in-wheel otor taes plae of the traditional engine and transission syste. opared with IE, it has any advantages [] and has beoe the researh fous of a new generation of eletri vehile tehnology. Purdy [] points out that the unsprung ass of the vehile inreases due to the introdution of in-wheel otor, whih enlarges the dynai load of the tire and the vehile body vibration aeleration, thus the tire grounding perforane and ar ride ofort get worse; Liang [] designs a suspension devie for in-wheel otor based on the dynai vibration absorbing theory. The suspension stiffness and the daping value of the ative suspension syste an be adaptively adjusted aording to the hange of the autoobile driving onditions, so the suspension is always in the best daping state [4]. The sei-ative suspension is one type of ative suspension, whih onsist of variable paraeters of the suspension spring and daper. It adjusts the suspension stiffness value or daping oeffiient via a sall aount of energy. This paper does researh on EV driven by in-wheel otor, whih adopts the otor suspension devie and the agneto-rheologial sei-ative suspension.based on the vehile dynais theory, the three degrees of freedo odel of /4 vehile with agneto-rheologial sei-ative suspension and passive suspension are established respetively.the MATLAB/iulin is used to siulate the odel.finally the results of the siulation are analyzed in detail. Road input The road spae roughness is the basi input for ar Ride ofort and is the ain reason ausing the vehile to generate vibrations. Rando road an reflet the atual road ondition when driving.the filtered white noise is suitable as the road input odel. That is: y t π f y t π GV w t 5. The authors - Published by Atlantis Press 65

2 Where yt is road displaeent; G is road roughness oeffiient; wt is White Gauss noise, ean is zero; V is vehile speed; and f is ut-off frequeny,.hz. When the vehile drives on the level road at the speed of /s, G 56-6 / -. /4 vehile odel with agneto-rheologial sei-ative suspension and passive suspension The /4 vehile odel with agneto-rheologial sei-ative suspension/passive suspension is shown in figure a and figure b. Figure a. The /4 vehile odel with agneto-rheologial sei-ative suspension Figure b. The /4 vehile odel with passive suspension odel Where: :Unsprung ass :prung ass :Motor ass :Tire stiffness :uspension stiffness :Motor suspension devie stiffness :Magneto-rheologial daper inherent daping :Motor suspension devie daping A P :Piston effetive area D:ylinder diaeter L:Piston length h:interval between Piston and ylinder τ γ :hear yield stressτ γ :Magneto-rheologial fluid visosity F LA h LA p π LD τ γ sgn [ u t ] π LD τ sgn [ ] h p MR γ For /4 vehile odel with agneto-rheologial sei-ative suspension, the dynais equation is established based on Newton's law: F y MR FMR 4 5, tate variables [,,,, ] T Input variables U [ F MR, y ] T Output variables [,, y] T, The output variables are the vehile body vertial aeleration, Unspring ass aeleration, uspension dynai defletion and Tire run-out. They are the evaluation inde of the vehile suspension syste [5]. 66

3 DU BU A Dynais equation is ransfored to state spae equation: 6 Get oeffiient atri: A B D For the /4 vehile odel with passive suspension, we an also establish the dynais equation, transfor dynais equation to state spae equation and get the oeffiient atri A.B..D in the sae way. y-hoo daping ontrol strategy One oon sii-ative suspension ontrol ethod is y-hoo daping ontrol strategy. The odel is shown in figure. The daper is arranged between the sprung ass and the virtual inertia spae [6]. The orresponding y-hoo daping fore is: F y d 7 where, y is the y-hoo daping oeffiient and needs to be optiized aording to the suspension syste. 67

4 Figure. y-hoo daping ontrol strategy odel The dynais equation is established in order to deterine sy : y 8 y 9 Laplae transfor: ] [ ] [ ] [ y Transfer funtion of Tire: [ ] H y 4 Transfer funtion of ar ride ofort : H 5 To aintain the ideal aneuverability, the wheel needs to follow the road surfae profile under various onditions. The ideal suspension ride ofort requires the sprung ass reains stationary, so the ideal aplitude frequeny harateristis of H and H should be alost horizontal and lose to zero. The urves of aplitude frequeny harateristis of H and H are shown in Figure. The urves shows that the H is loser to the ideal aplitude frequeny harateristis when y inreases, while the tire run-out sharpens at the sae tie, whih aes the ontrol stability bad.oproising on the suspension ride ofort and ontrol stability, the reasonable y is Ns/. To be equivalent to the y-hoo dap, there is: MR Fd F 6 68

5 F MR LA h LA h p [ u t ] π LD τ sgn [ ] p π LD τ γ sgn γ When the signatures of and are the sae, F MR is equal to F d. Otherwise, in order to narrow the differenes, F MR should be zero. That is: F MR F d s < 7 Bode Diagra 4 sy 4 5 H Magnitude db - -4 H Phase deg -9 Frequeny rad/s Figure. urves of aplitude frequeny harateristis of H and H iulation odel Based on these two suspension odels, Matlab/iulin siulation odel is shown figure 4. The atual paraeters of the odel are as follows: 7g, 5g, 8g, 6N/, 474N/, 4N/, 9N//s, 6N//s,A p 5,D.,L8.4, h, τ γ 6 Pa,η. Pa s. Figure 4. Matlab/iulin siulation odel of two suspension systes 69

6 Results and disussion The response urves of vehile body vertial aeleration, suspension dynai defletion, the tire dynai load and the tire runout are shown in Figure 5~ ii-ative suspension.. ii-ative suspension Body vertile aeleration/s uspension dynai deflet Ties Figure 5. Vehile body vertial aeleration Ties Figure 6. uspension dynai defletion 5 ei- ative suspension 5-4 ii-ative suspension Tire dybai load N Tire run-out Ties Figure 7. Tire dynai load Ties Figure 8. Tire run-out opared with passive suspension,the sii-ative suspension iproves the vehile body vertial aeleration apparently,restrains the tire run-out,and enhanes the adhesion perforane of the tire. onlusions opared with the passive suspension syste,the agneto-rheologial sei-ative suspension syste with the "y-hoo" ontrol strategy iproves the ar ride perforane and ofort obviously. We tae the vertial three degree of freedo syste of EV driven by in-wheel otor based on the dynai vibration absorbing theory as an eaple, establish the dynais equation and transfor dynais equation to state spae equation further ore,finally ipleent the siulation. This proess provides a referene ethod for siilar vibration syste siulation with ulti degree of freedo. Referene []Murata.Vehile Dynais Innovation with In-Wheel Motor.AE Paper []Purdy J. D.A brief investigation into the effet on suspension otions of high unspung ass.journal of battlefield tehnology.4,7:5-. [] R.Liang,Z.P.u,G.B.Ning.The suppression of negative effet of in-wheel drive EV vertial vibration based on vibration absorption priniple.journal OF MAHINE DEIGN.8,5:8-. [4]G.L.Wang,L.Gu,F..un.The situation and trend of the tehnology of vehile ative 7

7 suspension.ata ARMAMENTARII.8,8:8-8. [5]Z..u.Autoobile theory.beijing:hina MAHINE PRE,9.. [6]M.u.Researh on the ontrol syste of autoobile agneto-rheologial sei-ative suspension[d].university Of hongqing,5 7