Structural design and motion analysis of Hexapod Bionic walking. device. Zhu Zhifang12

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1 4th Intrnational Confrnc on Machinry, Matrials and Computing Tchnology (ICMMCT 016) Structural dsign and motion analysis of Hxapod Bionic walking dvic Zhu Zhifang1 1.Jiangxi Provinc Ky Laboratory of prcision driv and control,nanchang,330099,china.nanchang Institut of Tchnology,Nanchang,330099,China Ky words: Bionics; foot walking dvic; structur dsign; motion simulation Abstract: Basd on th principl of bionics, this papr dsigns a hxapod walking dvic by using a crank rockr mchanism. Th dsignd structur can prform som basic walking oprations, such as forward and backward plac, turn lft, turn right and so on. Furthrmor, th triangl gait principl of th hxapod walking dvic and its stability ar analyzd, th ky parts of th dvic dimnsions ar calculatd in dtail, and th simulation of th body cntr of mass motion curv is prformd to tst th prototyp through th dynamic simulation softwar ADAMS. Th rsults show that th hxapod walking motion dvic is stabl, with good mobility, and mts th dsign rquirmnts. 1 Introduction With th dvlopmnt of scinc and tchnology, for th human cannot rach plac and may ndangr th complx nvironmnt of human lif ar incrasingly using mobil robot to complt, so can gratly avoid bad working nvironmnt of th harm to human body[1,]. Mobil robot, th whl or catrpillar mobil mthod is th most common way of moving, has bn widly applid, its advantag is that mov quickly, simpl control, if mobil procss road flat, rlativly stabl movmnt, th robot cntr of mass dos not chang[3,4]. But for complx irrgular and unvn ground nvironmnt, th foot typ mobil mod with whld and trackd mobil mod that th advantags of robots work in ordr to adapt to mor and mor complicatd nvironmnt, foot typ mobil robot rsarch has bcom a striking in robotics rsarch[5]. Basd on th bionics principl, with hxapod outlin inscts is a bionic prototyp, crank rockr mchanism as hxapod, and controlld by singl chip microcomputr, consists of two small dc motors with gar box as driving lmnt to dsign a kind of bionic hxapod walking dvic, and through th simulation softwar Adams is analyzd and th prototyp tst, rsults showd that th movmnt procss smoothly. Ovrall structur dsign of Hxapod walking dvic In this papr, th dsign diagram of th hxapod walking dvic structur is shown in figur 1. Th dvic structur including two parts: mchanical part and control part. Mchanical part is mainly composd of th body, two small dc motor, gar transmission mchanism, th six sts of four bar linkag[6]. Dc motor driv, th motor shaft position to spur gar, work through th motor output gar driv shaft rotation, thrby giving imptus to th movmnt of crankshaft movmnt to control th dvic. Du to th sam sid of th foot joints by th crank shaft and th shaft coupling, so it can b controlld by adjusting th crankshaft Angl similaritis and diffrncs as wll as th 016. Th authors - Publishd by Atlantis Prss 181

2 phas diffrnc of ach phas lg can achiv diffrnt gait, foot walking dvic is dsignd in accordanc with th "four bar linkag", is th crank and rockr mchanism typ usd. In th crank rotats, th robot's foot to wiggl th lliptical shap, so th movmnt is similar to stp whn walking. Driv hxapod by six of th crank to strictly consistnt, thr foot touchs th ground at th sam tim, th sam crank to b practical. At this point, th thr lgs of th crank from th ground to rotat 180 dgrs, corrct installation of th crank is rlatd to th robot walking pac to th right. 1.Bas plat;. Your front foot; 3.Controllr; 4. Conncting rod; 5. Motor; 6. Vrtical bar; 7. Cross bar; 8. Driv gar; 9.Output gar; 10. Hr ft; 11. Hind ft Fig.1. Structur of hxapod bionic walking dvic.1 Foot dsign of walking dvic Hxapod should b dsignd according to th siz of th dvic as a whol, th ky is to st foot should not b too big or too small, if th foot is too small, it will not b abl to jack th whol jacking dvic [7] ; if th foot is too larg, ft walking dvic will hav to ovrcom a lot of work, so th foot of this dvic st should b modst, should b dsignd in btwn 0 to 40 dgrs. As shown in figur is th prototyp of hxapod modl diagram. 1.Crankshaft;. Rail;3. diffrnt turning points in th uppr part; 4. ft rod rotation point in uppr part Fig.. Hxapod structur Crankshaft lngth is st a, two rail lngth for b, uppr cntr turning point lngth for diffrnt, top lngth of foot pol cntr rotating point in g. Whn th crankshaft movmnt to th highs and lows, thr ft paralll and vrtical to th ground, so th top rquir diffrnt rod cntr on a lvl with th crankshaft and th both ft and th horizontal distanc btwn th foot in f= b a, forfoot rod rotation cntr and th crankshaft cntr distanc of: b a + St th initial position, th front foot pol and rotation cntr and th Angl btwn th crankshaft cntr for α, th currnt rod rotation θ to maximum pndulum foot, foot on th 18

3 crankshaft and rod in th sam lin, th front foot pol and rotation cntr and th Angl btwn th crankshaft cntr for β. cosa = So: b a + a = arccos (1) b a + Rod rotation to maximum pndulum is currnt th ft, th crankshaft and th cross bar on th sam lin, st th front foot pol and rotation cntr and th Angl btwn th crankshaft cntr for β, on th front foot ndpoint with th crankshaft cntr distanc of b + a, basd on th cosin thorm. cos b = So: + b a b + a ( a + b) + = a ab b a + a ab b = arccos () b a + Both ft st foot is largst for: θ = β α (3) Through th abov (1), () and (3) formula can vn draw a diffrnt solution st foot is largst, th rsults calculatd formula is as follows: a ab θ = arccos arccos (4) b a + b a + 3 Analysis of Hxapod bionic gait Th hxapod bionic robot is thr ft on on sid of th pol synchronous motion, on both sids of diffrnt motor driv control through two groups of foot pol movmnt rspctivly [8], th both ft on on sid of th fixd triangl formd and on th othr sid of th foot, two groups of triangular intraction can raliz th hxapod bionic robot walk straight, turn and lock. Th bar top trajctory is shown in th following figur. Fig.3. Foot bar at th top of track 3.1 Foot pol movmnt procss analysis Foot pol movmnt procss is shown in figur 4 : 183

4 Fig.4. Foot pol movmnt procss (1)Whn th initial position, th crankshaft is prpndicular to th ground, thr ft paralll and both ft on th ground, carrid to th highst position in th ft. ()With conncting rod crank shaft to rotat countrclockwis to on th sam lin, bfor and aftr th bar clockwis to maximum st foot. (3)Crankshaft countrclockwis rotation, half a circl at this point in th foot with th othr masurmnt of vrtical ground common to jacking dvic at diffrnt rotary to paralll to th pol in diffrnt tims. (4)Crank shaft rotat countrclockwis to th conncting rod on th sam lin, diffrnt rotat countrclockwis to maximum pndulum ft, foot in clockwis to th ground. (5)Crankshaft countrclockwis rotation a wk to th origin, th ntir unit to complt a cycl of walking. 3. Basd on Admas cntroid dynamics analysis In ordr to rsarch cntr of mass of th movmnt of walking dvic, application of cntr of mass for th dynamic simulation of Adams softwar, th simulation rsults ar shown in figur 5 and figur 6, th curv for th cntr of mass in th cas of vrtical vlocity changs: Fig.5. Th cntroid position chang curv Fig.6. Th cntr of mass vlocity curv Can b sn from th cntr of mass position and vlocity curv, th cntr of mass 184

5 cntr of gravity in th vrtical dirction of fluctuating 1 mm, maximum amplitud of th mass cntr around bfor and aftr th location of th chang to nar zro. And th chang of th cntr of mass vlocity in th vrtical dirction is basically in accordanc with th law in a changing, th cntr of mass movmnt spd is about 39 mm/s, th biggst intgral curv is vry smooth, basically th fluctuation is not big, uniform spd chang, it can b sn walking dvic running vry smooth, no obvious fluctuation. 4 Prototyp tst Th bionic analysis robot physical diagram is shown in figur 7. Producd by th body USES th high strngth aluminum alloy matrial, six lgs ar mad of 45 stl, which could gratly improv th ovrall strngth. As shown in figur of Hxapod robot is locatd in th mdian, th ovrall lngth and 400 mm, 160 mm wid, 00 mm high, middl lgs and back bfor th sit distanc is 170 mm, th ovrall quality of.5 kg. Fig.7. Physical objcts of hxapod bionic robot 5 Conclusion In viw of th xisting hxapod dvic structur dsign, hxapod trajctory problms such as unclar, basd on bionics principl, solvs th xisting walking dvic structur dsign, trajctory analysis problms such as unclar, mainly for th gnral structur of th walking dvic dsign, main componnts of th motion simulation and prototyp production, tc. Walking through th plant ovrall structur dsign, th us of six bar linkag for bionic movmnt, th dsign principl of hxapod, obtaind th gait principl; Paramtrs for th ky parts dsign and application of Adams softwar modling and simulation, th movmnt of mass cntr of moving dvics, dynamic simulation curvs, th rsults show that th dvic rasonabl ovrall structur dsign, th cntr of mass movmnt smoothly, and finally mad a prototyp xprimnt, ffct is good, has rachd th xpctd dsign purpos. Acknowldgmnt In this papr, th rsarch was sponsord by th Youth Scinc Fund of Nanchang Institut of Tchnology(Grant No.014KJ01)And 015 Outstanding graduation thsis of Nanchang Institut of Tchnology. Rfrncs 185

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