Design of Retracting Wheel Mechanism for Amphibious Vehicle and Motion Analysis Huan Chen a, Lijie Zhao b*, Yan Li c

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1 nd Inernaional onference on lecronic & echanical ngineering and Informaion Technology IT- esign of Reracing Wheel echanism for mphibious Vehicle and oion nalysis uan hen a Lijie hao b* an Li c School of echaronic ngineering Shenyang erospace Universiy hina a chenhuan9895@63.com b zhaolj@sau.edu.cn c liyan5437@63.com Keywords: amphibious vehicle; reracing wheel mechanism; moion analysis bsrac- This paper mainly addresses design of reracing mechanism based on amphibious vehicle's low speed and srong resisance in waer. Through analyzing problems faced in he design of amphibious vehicle one kind of reracing mechanism based on double-wishbone independen suspension is proposed. The equaions of key-poins a suspension guiding mechanism are obained and he relaionship beween he lengh of hydraulic sick reraced and he heigh of wheel lifed are also calculaed. inally a specific 3 model is buil and wheel alignmen is deermined herefore a real mechanism is assembled o illusrae he reracing mechanism. Inroducion In recen years flood disasers happened frequenly because global climae is changing. The amphibious vehicle ges more aenions. I can play a unique performance in juncion of land and waer. mphibious vehicle plays imporan roles in rescuing in flood disaser and has also became essenial weapons especially coas defense. The UK and Swizerland ha developed he high-speed amphibious vehicle named quada and Splash have he leading posiion around he world []. u many key echnological problems have o be solved in order o suffice he funcion of he amphibious vehicle and he reracing wheel mechanism is one of he key echnological problems in waer. ccording o a sudy in U.S he resisance of wheel in waer accouns for 5% of vehicle resisance [] so reracing wheels ino he wheel housing can preven hem from dragging hrough he waer and enable he amphibious vehicle o plane faser and maneuver beer. or he purpose of high speed cruising he guiding mechanism of suspension is needed o redesign [3 4]. ig. irec-reracing on land ig. irec-reracing in waer Through analyzing above he mechanism named direc-reracing is proposed in ig. and ig. he main funcion of his mechanism provides convenional sandards of ride and handing when i is on land and reracs wheels ou of waer o reduce hull drag. I is based on double-wishbone independen suspension. The amphibian senses when i is in waer and so will no allow reracing is wheels when on land. ydraulic pressure is applies o he hydraulic sru which lifs he wheel o is reraced posiion [5]. The hydraulic sysem and shock absorber are combined by line and he hydraulic sysem is mouned under shock absorber. The sru hydraulic ha needs o provide normal suspension and rerac he wheels is he imporan par of his mechanism. * orresponden auhor: zhaolj@sau.edu.cn Published by lanis Press Paris rance. 87

2 nd Inernaional onference on lecronic & echanical ngineering and Informaion Technology IT- odel efore designing his mechanism here is a principle needed o noice ha he Shock bsorber axis should be verical wih he vehicle longiudinal axis. The purpose is ha he inerference is avoided beween shock absorber and lower conrol arm when lifing wheel as shown in ig.3.. ig.3 iagram of Shock bsorber mouned ig.4 iagram of lifing mechanism The Relaionship of irec-reracing oion. s shown in ig.4 he process of movemen of direc-reracing is described by he diagram. The siuaion ha amphibian is on land is shown by solid line and in waer by doed line. So some equaions are obained hrough geomeric relaionships. b sin α θ a h a cos α θ π θ L 8 L b b Release o 8 θ πl b L asin α θ Where L is he lengh of lower conrol arm L is he lengh of hydraulic sysem normal L is he lengh of hydraulic sysem reracing a is disance from he upper poin of hydraulic sysem o axis of lower conrol arm α is he angle beween a and verical direcion is he heigh of wheel lifed in he case <3mm which he heigh of lower ball join lifed is considered as he heigh of wheel lifed. They are known as he parameers of vehicle excep L and. I is easy o show ha he relaionship from above diagram: L b h Δ L L Where Δ which is reracable lengh of hydraulic sysem is given by equaion only expressed as : Δ L L L L asin α a cos α πl πl quaion 3 is only applied o he mechanism based on double-wishbone independen suspension. oion nalysis of Independen Suspension uiding echanism. When he guiding mechanism of fron wheel suspension is designed wo poins are noiced: when he vehicle is driving read should be on cerain range; when fron wheel is jump up and down wheel alignmen has reasonable change [6 7]. Published by lanis Press Paris rance. 88

3 ig.5 iagram of independen suspension ig.6 iagram of lower conrol arm s shown in ig.5 is lower conrol arm bushing is lower ball join P is he shaf and K is poin of wheel on ground. and are shown by coordinae so he direcion of vecor is shown { } { } n Where: / / ; Line is described by equaion 4: 4 The plane which is verical wih and passes is described by equaion: 5 coordinae is obained by equaion 4 and equaion 5: Where: [ ] / The lengh of is described by equaion 6: l 6 The equaion of rack which is a sphere ha uses o he cener of sphere is expressed as l 7 When wheels jump up and down he final equaion of is obained by equaions 5 and 7. l 8 Through analysis above similarly he equaion of can be formulaed. q 9 Where 89 nd Inernaional onference on lecronic & echanical ngineering and Informaion Technology IT- Published by lanis Press Paris rance.

4 nd Inernaional onference on lecronic & echanical ngineering and Informaion Technology IT- q p / p / p p [ ]/ Wheel alignmen. Wheel alignmen is he process of measuring and correcing he various angles formed by he fron wheels spindles and seering arm. ccording o ig.5 alignmen can be given. aser: α arcan Seering axis inclinaion: β arcan amber: arcan γ Toe angle: δ arcan pplicaion Through analysis above one real prooype is assembled o realize he reracing movemen. ased on he prooype chassis he reracing mechanism model is buil and simulaed hrough U package as shown in ig.7 and 8: ig.7 The eniy of reracing mechanism ig.8 The 3-model of reracing mechanism The coordinae of poins in ig.5 is exraced from U package and shown in Table. or his he wheel alignmen is obained. α.36 β 5.9 γ.4 δ. 7 If wheels jump in he range from -4mm o 4mm ha reflec he deflecion caused by road roughness when vehicle is driven on land he range of wheel alignmen is shown as aser:.35~.37; Seering axis inclinaion: 5.5~9.3; amber:.3~.5; Toe angle:.3~; Table he coordinae of poins coordinae poin P K Through analyzing above daa wheel alignmen is reasonable excep ha seering axis inclinaion has large changes due o he posiion of Kingpin described by coordinae in Table bu he funcion of suspension is barely influenced herefore he design of suspension for reracing mechanism is feasible. Published by lanis Press Paris rance. 8

5 nd Inernaional onference on lecronic & echanical ngineering and Informaion Technology IT- onclusions In order o solve he problem ha amphibious vehicle has low-speed in waer he direc-reracing mechanism is designed. Through kinemaic analysis for he mechanism he equaions ha describe rack of poins of suspension are driven and he relaionship beween he lengh of hydraulic sick reraced and he heigh of wheel lifed is obained. The resuls of wheel alignmen show ha he direc-reracing mechanism based on double-wishbone independen suspension can be used in amphibious vehicle o improve is driving performance. I is expeced ha he resuls shown in his paper could be applied o he design of new amphibious vehicle. References [] K.Wu W.Wang.hao: Special Purpose Vehicle Vol. 4 p.5-6 [].Q.ang: mphibious Vehicles Principles and esign Trans achine Publicaions hina 3 [3].P.Jia K.L.u: Journal of cademy of rmored orce ngineering Vol p [4] S..hen..Wu L.ang.hang: Vehicle and Power Technology Vol. 9 p.6-64 [5] Informaion on hp:// [6].u.L.heng: uomoive ngineering Vol p [7].W.ai.L.u J.Liu: Vehicle & Power Technology Vol. p.9-33 Published by lanis Press Paris rance. 8