Simulator for Hydraulic Excavator

Transcription

1 Smulator for Hydraulc Excavator Tae-Hyeog Lm*, Hog-Seo Lee ** ad Soo-Yog Yag *** * Departmet of Mechacal ad Automotve Egeerg, Uversty of Ulsa,Ulsa, Korea (Tel : ; E-mal: bulbaram@mal.ulsa.ac.kr) **Departmet of Costructo Equpmet, Hyuda Heavy Idustry, Ulsa, Korea (Tel : ; E-mal: hsl@hh.co.kr) ***School of Mechacal ad Automotve Egeerg, Uversty of Ulsa, Ulsa, Korea (Tel : ; E-mal: sooyy@ulsa.ac.kr) Abstract: Hydraulc excavators have bee popular devces costructo feld because of ts mult-workgs ad ecoomc effcecy. The mathematcal models of excavators have may oleartes because of olear opeg characterstcs ad dead zoe of ma cotrol valve, ol temperature varato, etc. The objectve of ths paper s to develop a smulator for hydraulc excavator usg AMESm. Compoets ad whole crcut are expressed graphcally. Parameters ad olear characterstcs are putted text style. The smulator ca be used to forecast excavator behavor whe ew compoets, ew mechacal attachmets, hydraulc crcut chages, ad ew cotrol algorthm are appled. The smulator could be a kd of developmet platform for varous ew excavators.. Keywords: Excavator, AMESm, Attachmet, Hydraulc crcut. INTRODUCTION Hydraulc excavator have bee popular devce costructo feld because of ts mult-workg ad ecoomc effcecy. The applcato of ths complex devce wll be exteded maufacture, agrculture, udersea etc. But ts operatg eed very dffcult skll because operator has to operate joystcks ad pedals cosequetly. So accuracy of work s flueced by operator s skll. But evromet of work s poor ad dffcult skll brg about feelg fatgued fast. Autoomous excavator ca be a kk of soluto about prevous problems ad may researches have bee acheved by may researchers. Brtsh Columba uversty Caada, Carege Mello uversty USA ad Sydey uversty Australa have feld robot ceter ad have made a specal studes wth excavator ad may costructo equpmet makes have prototype or autoomous excavator part. The paper map feld robot wth excavator made before my laboratory show that 56 % of papers focus modelg of attachmet (Boom, Arm, Bucket) usg Lagrage Euler equato ad applyg cotrol algorthms but hydraulc crcut ad valves are modeled very smply. For example, ma cotrol valves havg olear ope area characterstcs are modeled smple varable orfce ad logc valves are omtted. I may paper, researchers use robust cotroller order to overcome oleartes created by complex ope area characterstcs ad dead zoe of valve, sgle actg cylder, heavy weght of attachmet. Because of may oleartes, expermets are postvely ecessary but lmted by tme, moey, place etc. The objectve of ths paper s to develop a smulator for hydraulc excavator usg AMESm. Compoets ad whole crcut are expressed graphcally. Parameters ad olear characterstcs are putted text style. The smulator ca be used to forecast excavator behavor whe ew compoets, ew mechacal attachmets, hydraulc crcut chages, ad ew cotrol algorthm are appled. The smulator could be a kd of developmet platform for varous ew excavators. 2. ATTACHMENT MODEL Hydraulc excavator cosst of upper frame, lower frame ad attachmet. Upper frame cota operatg room, ege, pump, ma cotrol valve (MCV) ad attachmet s fxed to ed of upper frame. Lower frame cota crawler or wheels ad upper frame ca rotate by swg motor. I ths paper, attachmet s modeled boom, arm, bucket except swg ad drve ad excavator model s 5 to of Hyuda Heavy Idustry. 2. Attachmet model Fg. The A hydraulc excavator Fg. 2 shows the coordate systems of excavator ad moto equato was establshed by Lagrage equato. j= j j j= H q& + h q& q& + G = Q, =,..., () k= jk j k H q & s erta torque cludg teracto torque by off j j dagoal elemet of attachmet erta tesors, h jk q& jq& s k Corols ad cetrfugal effects ad G s gravty torque.

2 Fg. 4 Hydraulc crcut of excavator Fg. 2 Coordates system Fg. 3 preset AMESm model of attachmet. The supercompoet of attachmet s show rght ad upper part fg. 3 ad ths cota the rest compoets. Each compoet cota lk s characterstc-legth, mass, erta etc. The coordates fg. 2 are cotaed the attachmet supercompoet. The puts of supercompoet are force of cylder ad outputs are agular dsplacemet of boom, arm ad bucket. 3. Joystck The role of joystck s supplyg plot pressure to MCV by operate agle. The AMESm model of joystck s show fg. 5. compoets dotted square are cotaed supercompoet left had sde. Operatg of joystck s assumed to sgal betwee - to ad plot pressure to A, B port s drectly proportoal to sgal. The put sgal to joystck model s fg. 6 (a) ad plot pressure at port A, B s (b). I fg., plot pressure respose s proportoal ad delay s rare. Fg. 5 AMESm model of joystck Fg. 3 AMESm model of attachmet 3. HYDAULIC CIRCUIT MODEL Ma pump operated by ege make two type of pressures that ma pressure work each cylder ad plot pressure work spool of ma cotrol valve by operatg joystck. If operator hadle joystck or lever, plot pressure push the spool of MCV, the rate ad drecto of flow s decded by spool dsplacemet ad drecto ad flow rate ca decde of drecto ad velocty of cylder. Workg area s assumed 2D ths paper, hydraulc crcut ca be smplfed lke fg. 4. Because boom up ad arm dump eed much flow rate, jo of flow rate betwee boom valve ad boom 2 valve, arm valve ad arm 2 valve. (a) Iput sgal (b) Plot pressure at A, B port Fg. 6 Result of joystck model 2

3 3.2 Pump The pump assembly cosst of 2 varable pump for ma pressure ad fxed pump for plot pressure. Varable pump has cotrol algorthm for eergy savg, ths ca be characterzed to P-Q dagram. The AMESm model of pump assembly s show fg. 7. Varous P-Q dagram ca be tested ths model easly because P-Q dagram s serted by text fle. For verfcato of pump model, put ad output P-Q characterstcs are show fg. 8. The sold le s put ad dotted le s output. Ths pump model s verfed wth valve ad cylder. Fg. 0 AMESm model of Boom valve Fg. 7 AMESm model of pump P-Q Fg. Spool dsplacemet varable stffess Q [L/m^ P [kg/cm^2] AMESm Result Orgal Fg. 8 Result of pump model Stffess varato has fluece upo valve dsplacemet. Too low stffess produce oscllato of spool ad errors betwee up ad dow are dfferet to each other make the error to mmum ad spool dsplacemet s show fg. 2. The dsplacemet error at boom up s 0.36[mm], at boom dow s 0.6[mm]. 3.3 Boom valve Boom valve, decde drecto ad velocty of boom cylder maly, s modeled 6 port 3 posto valve. The spool dsplacemet-ope area dagrams cota may oleartes dead zoe, saturato ad uproportoal characterstc. These olear dagrams are put to model text fle. Fg. 9 show ope area dagrams. The velocty of boom cylder at up ad dow wll be dfferet because of osymmetrcal dagram. Fg. 0 s AMESm model of boom valve. The compoets dotted square are packed to super- compoet left had sde fg. Fg. show that spool dsplacemet varous sprg stffess. PH RT PR HT PH-data RT-data HT-data PR-data Fg. 9 Ope area dagram of boom valve Fg. 2 Spool dsplacemet at stffess 7000 [ N 2 ] m 3.4 Boom 2 valve The role of boom 2 valve s supply flow rate to boom cylder at boom up. The boom 2 valve model has same structure wth boom valve model ad dfferet ope area dagram make the error to mmum ad spool dsplacemet s show fg. 3. The dsplacemet error at boom up s.02[mm] 3.5 Arm valve Arm valve, decde drecto ad velocty of Arm cylder maly, has same structure wth boom valve model ad dfferet ope area dagram make the error to mmum. The dsplacemet error at arm dump s [mm], at arm crowd s 0.284[mm]. 3.6 Bucket valve The fal sprg stffess of bucket valve s ad error at bucket dump s 0.042[mm], at bucket crowd s 3.7[mm]. 3

4 4. TOTAL MODEL & SIMULATION Total excavator model s costructed fg. 6 usg prevous models. Fg. 3 Spool dsplacemet varable stffess Fg. 6 AMESm model of excavator Fg. 4 Spool dsplacemet at stffess [ N 2 ] m 3.7 Ma Cotrol Valve (MCV) The ma cotrol valve block cosst of prevous hydraulc compoets(3.~3.6) s show fg. 5. The workg flud through by pass go to tak ad feature of crcut s smlar to smplfled crcut fg. 4. The port relef s added to cylder, out port. Though stffess tug was doe, results at complex moto s dfferet from t at sgle moto. Smulato codto s that operate joystck 50 [%] to + for 4 [sec], 50 [%] to -, 00 [%] to + ad 00 [%] to of boom, arm ad bucket smultaeously. Fg. 7 show spool dsplacemet of boom valve ad boom 2 valve uder smulato codto. Dsplacemet error s bgger tha smple moto that s because pressure at cylder effect to MCV. Fg. 8 show agular dsplacemet of attachmet ad pressures at boom cylder are show fg. 9. Fg. 7 Spool dsplacemet of boom valves at complex work Fg. 5 AMESm model of MCV Fg. 8 Agular dsplacemet of attachmets 4

5 Fg. 9 Pressures of boom cylder 5. CONCLUSION & FUTURE WORK Each compoet of attachmet ad hydraulc crcut of excavator ad total excavator s modeled wth AMESm. To fd costat sprg stffess make error to mmze tug has doe each valve model ad result s as follow. For boom valve error at boom up s 0.36[mm], boom dow s 0.6[mm] wth stffess I case of boom 2 valve, error at boom up s.02 [mm] wth stffess Arm valve, error at arm dump s , arm crowd s [mm] wth stffess I bucket valve, error at bucket dump s 0.042[mm], at bucket crowd s 3.7[mm] wth stffess So, costat sprg stffess ca t satsfy accuracy of spool dsplacemet for all codto. I order to proportoal to dsplacemet of MCV t s eed to costruct closed loop type MCV. The AMESm model for total excavator wll be used to verfy ew cotrol algorthm or ew compoet. Uder beg may lmt to make a expermet wth real excavator, ths AMESm model wll play a actve part smulator or test bech. ACKNOWLEDGMENTS Ths work was supported by the Korea Scece ad Egeerg Foudato (KOSEF) through the research ceter for mache parts ad materal processg at Uversty of Ulsa ad Hyuda Heavy Idustry. REFERENCES [] T. R. Kae, "Dyamcs : Theory ad Applcatos", McGraw-Hll, 985. [2] R. P. Paul, "Robot mapultors : Mathematcs, Programmg, ad Cotrol", The MIT Press, 98. [3] J. Watto, Flud Power Systems, Pretce Hall, 989. [4] AMESm User's Maual, IMAGINE, [5] S. Y. Yag etc. "A Study o Trajectory Trackg Cotrol of Feld Robot", ICASE, Vol8, No.9,