P-06 Proceedings of the 7th JFPS Interntionl Symposium on Fluid Power TOYAMA 008 September 5-8 008 A HYDRAULIC SIMULATOR FOR AN EXCAVATOR Soon-Kwng Kwon* Je-Jun Kim* Young-Mn Jung* Chn-Se Jung* Chng-Don Lee** nd Soon-Young Yng* * Deprtment of Mechnicl nd Automotive Engineering Fculty of Engineering University of Ulsn Dehkro 0 Nm Gu Ulsn 680-749 Kore (E-mil: kwng504@hotmil.com ** Tem of Technicl Development for Intelligent Vehicle Prts Fculty of Engineering University of Ulsn Dehkro 0 Nm Gu Ulsn 680-749 Kore ABSTRACT An excvtor consists of severl hydrulic components which include pumps min control vlve nd cylinders etc. It opertes by the linkge of the components. This pper is concerned with development of hydrulic simultor for n excvtor. The simultor hs been developed using AMESim bsed on specifictions of.5 ton excvtor. The excvtor hs been instlled dditionl components to investigte n utomted field robot; Electro proportionl pressure reducing vlve electronic joysticks ngle sensors nd controller ws instlled t the excvtor. The developed hydrulic simultor hs the bility to represent with nimtion. The modeled MCV hs been pplied non-liner open re of spools. KEY WORDS Excvtor Simultion AMESim MCV INTRODUCTION The Hydrulic excvtor hs been the best populr construction equipment becuse of its multi-working bility in the construction field [-]. However its energy efficiency nd prevention of environmentl crisis re still need to improve. The cpbilities of controllers nd components hve been tested t the excvtor directly. However these tests ccompny with lots of time risk resources. In order to develop efficiently simultion is necessry before the test. This pper describes the hydrulic simultion of excvtors. Components nd hydrulic system re built using the AMESim. MODELING OF COMPONENTS In order to develop the hydrulic simultor first ech component ws modeled. MCV Joysticks ttchment were newly modeled in this pper. These component modeling re bsed on.5 ton hydrulic excvtor. Min Control vlve The MCV consists of vrious vlves for boom rm bucket trvel motor dozer nd swing etc. Only the vlves of boom rm nd bucket re considered in this pper. These vlves re 6 ports 3 position types including bypss circuits. The Fig. is shown circuit digrm of boom vlve. When spool is in neutrl the bypss line Copyright 008 by JFPS ISBN 4-93070-07-X
is completely open. If pilot pressure ct to one side of vlve selectively spool is moved in ccordnce with the pressure. Then the open-re shows non-liner reltion with spool displcement s sme to the Fig.. Figure Circuit digrm of the boom vlve Figure 4 AMESim model of the joystick Figure Stroke-Open re chrcteristics of boom vlve The boom vlve ws designed in order to include the direction of spool nd non-liner open-re using the AMESim s shown in Fig. 3. Attchment The size nd weight of ttchment ws obtined by mking n ctul survey. In order to strt the simultion t wnted shpe of the ttchment the initil ngulr position of boom rm nd bucket hd to be decided. It needed to obtin the geometry modeling. A coordinte system ws determined with 3 degrees of freedom s shown in Fig. 5. Although the reltive ngulr position of ech component hs used generlly to study bout n excvtor [3-5] the bsolute ngulr position which is suitble for the modeling using the AMESim hs been used in this pper. Figure 3 Modeling of the boom vlve using the AMESim Joystick As for most movements of excvtor it is cted with opertions of joysticks. The opertions decide on pilot pressure nd direction. The pilot pressure hving rnge of 0kg/cm to 0kg/cm re used. These pressure nd direction move spools of the MCV then hydrulic oil pss through open-re which re generted by the movement of spools. In this pper operting of joysticks is ssumed to signl between - to nd pilot pressure to A B port is directly proportionl to signl. The models of joysticks re sme to Fig. 4. Figure 5 Coordinte system of the ttchment The joints of boom rm nd bucket re denoted s O b (x b y b O (x y nd O k (x k y k. Their points re obtined using Eqs. ( ~ (3. x b y b 0 0 ( Copyright 008 by JFPS ISBN 4-93070-07-X
k x x L y k L cosb y L sinb ( L cosb L sin b L cos sin. (3 where b re the bsolute ngulr positions of boom nd rm. l l r r cos cos cos cos l l l l L4 L l L 4 3 L6 L l L 3 L3 L l L 3 5 4 L5 L l L 5 6 o cos L 4 L3 l L4 L3 l ( 80 l l (7 r o ( 80 r r. (8 Figure 6 Four-br linkges system Fig. 6 shows the four-br linkges which contin rm bucket control link nd control rod. Eq. (4 is shown the coordinte point of joint which connect rm nd control link nd Eq. (5 is represented joint which connects bucket nd control rod. The ttchment ws modeled using these equtions nd mesuring dt s shown in Fig. 7. This model includes contour dt of boom rm nd bucket so we cn confirm the virtul movement of the ttchment through simultion result. x L l y L l cos b ( L L4 sinb ( L L4 cos sin (4 xr L cosb L cos L3 sin( c k yr L sinb L sin L3 cos( c k. (5 where k is the bsolute ngulr position of bucket. The distnce l of O l nd O r is sme to Eq. (6. l ( xl xr ( yl yr. (6 The initil ngulr position of the control link nd control rod cn be clculted using the second lw of cosines s shown in Eqs. (7 ~ (8. Figure 7 Attchment model using AMESim Pump An pplied excvtor hs got three hydrulic pumps. One pump ws lredy shown in Fig 4. The pump is used to control pilot pressure. The orders re fixed cpcity type ech flowing out 5.cc/rev. A pump minly tke chrge of the movement of the rm. And pump usully concern with motion of boom nd bucket. When the cylinder need much flow rte pump cn concern with the opertion through check vlve. Copyright 008 by JFPS ISBN 4-93070-07-X
Cylinder Attchment is moved by stroke vrition of three cylinders. The specifiction of cylinders is the sme to Tble. In this study the weight of cylinders hs been ignored. Tble specifiction of cylinders Boom Arm Bucket Piston dimeter 55mm 55mm 55mm Rod dimeter 30mm 30mm 30mm Length of stroke 0.38m 0.39m 0.3m Free length 0.6m 0.6m 0.5m MODELING OF SYSTEM The hydrulic simultor system for the excvtor ws completed by ssembly of ech component. The models of the ttchment nd vlves re setting up to ech seprte subcomponent. This simultor system works ccording to input signls hving rnge of - to which they move vlve spools. Relief vlves set up the mximum pressure in the system to 0 kg/cm. Fig.8 shows the hydrulic simultor system using the AMESim. Two pumps turn to the sme speed becuse they re connected with the only engine. And the flow rtes re lso sme. Figure 9 Joystick signls The moving direction of ttchment ccording to input signl ws decided the sme to Tble. Tble Input signl-moving direction chrcteristics Boom Arm Bucket + (positive up crowd crowd - (negtive down dump dump When input signls re the sme to Fig. 9 ech cylinder stroke is ppered s shown in Fig. 0. Figure 0 Cylinder strokes Fig. shows the reltive ngulr positions nd Fig. shows the bsolute ngulr positions of the ttchment. Figure Reltive ngulr positions Figure 8 Circuit digrm of simultor using the AMESim EXPERIMENT We ssumed to work excvtion nd then the signls were inputted to ech vlve. An engine speed ws supposed to 300rpm. Then the input signls re sme to Fig. 9. Figure Absolute ngulr positions The pressure t both ends of cylinders is lso obtined by this simultion s shown Fig. 3. Copyright 008 by JFPS ISBN 4-93070-07-X
Figure 5 A scene of nimtion Figure 3 Cylinder Pressure This hydrulic simultor clcultes not only bove-mentioned things but lso mny other thing trjectory flow rte shft torque etc. Fig. 4 shows the flow rtes t both ends of cylinders in the sme simultion. Figure 6 A photo of the pplictory excvtor CONCLUSIONS Figure 4 Flow rte t ports of cylinders The simultion ws operted nd we obtined the results of tht. We cn confirm the results more quickly nd esily by n nimtion function. Fig. 5 is scene of the nimtion bsed on the results of the excvtion work. In this study the hydrulic simultor is developed for the excvtor. The mechnicls hve been modeled in ccordnce with the specifics nd mesuring of the excvtor. The input signl into the MCV cn be controlled in the simultor. Becuse the MCV model includes chrcteristic of non-liner open-re in ccordnce with displcement of spools it is more effective thn other studies which use feed-bck system with liner open-re vlve. Vrious results re obtined by the virtul excvtion work.. We re going to mesure the pressure nd ngulr positions using the excvtor s shown in Fig. 6. The mesuring dt nd results of simultion will be compred ech other to evlute the simultor. After rectifiction nd supplementtion it is expected tht this hydrulic simultion progrm re pplied utomtion study performnce test of component etc. Copyright 008 by JFPS ISBN 4-93070-07-X
ACKNOWLEDGEMENTS This study ws supported by Hyundi Hevy Industries co. nd Post Brin Kore Republic of Kore. REFERENCES. Jong-Hwn Choi Sung-Su Kim Soon-Yong Yng nd Jin-Gul Lee Robust Trjectory Control of Hydrulic Excvtor using Disturbnce Observer in H Frmework Journl of the Koren Society of Precision Engineering 003 0-0 pp.30-40.. Sung-Su Kim Woo-Suk Seo Soon-Yong Yng Byung-Ryong Lee nd Kyung-Kwn Ahn Trjectory Control of Field Robot Using Adptive Control nd System Identifiction Journl of Control Automtion nd Systems Engineering 00 8-9 pp.78-735. 3. Tomi Mkkonen Kelervo Nevl nd Runo Heikkilä A 3D model bsed control of n excvtor Automtion in Construction 5 006 pp.57-577. 4. P. K. Vähä nd M. J. Skibniewski Dynmic model of excvtor Journl of Aerospce Engineering 993 6- pp.48-58. 5. Seung Ho Cho A Simultion on the Hydrulic Control Chrcteristics of Excvtor Using Lod Sensing System Journl of the Koren Society of Precision Engineering 998 5- pp.34-45. 6. AMESim user Mnul IMAGINE 000. 7. John Wtton Fluid Power System Prentice Hll 989. Copyright 008 by JFPS ISBN 4-93070-07-X