A Development of Embedded System for Speed Control of Hydraulic Motor

Transcription

1 AISTPME (2011) 4(4): A Development of Embedded System for Speed Control of Hydruli Motor Pornjit P. Edutionl Mehtronis Reserh Group Deprtment of Teher Trining in Mehnil Engineering, KMUTN, ngkok, Thilnd Wthrin P. Edutionl Mehtronis Reserh Group Deprtment of Teher Trining in Mehnil Engineering, KMUTN, ngkok, Thilnd Kwnhi S. nd Surhet S. USE.FO-INE Co, td, Pthumthni, Thilnd Abstrt In the present study, high-performne eletro-hydruli motor ontroller is designed nd developed by using embedded tehnology. These eletro-hydruli motor is ontrolled using designed lgorithms in ARM7embedded bord with grphil progrmming. An optil enoder is used to detet hydruli motor speed by reding vi timer in ARM7. Hydruli proportionl vlve is employed to ontrol the flow of hydruli motor by mnipulting PWM signl. The ontrol pprohes hve been tested for the funtion bility of the tutor, whih is speed ontrol. The results hve shown tht the system works suessfully nd gives good performne for prtil pplitions. Keywords: embedded, eletro-hydruli motor ontrol 1 Introdution Hydruli tutors re used to trnsfer energy by onverting fluid energy to mehnil energy. It plys n importnt role in modern industry where ontrolled speed or position with high ury is the most signifint demnd. The rtio of weight, volume, nd inerti to vilble power is signifintly lower thn in eletro-mehnil drives nd the dynmi performne re superior. Mny reserhes on hydruli motor ontrol hve been proposed new ontrol lgorithm to improve the overll performne of the system [1-3]. However, the requirement to implement dvned ontrol strtegies hs led to n inresed interest in the employ of embedded tehnology in this field. One design pproh, whih merits speil onsidertion in this reserh, is the use of grphil progrmming with bview to rete the Grphi User Interfe, nd to generte nd test embedded ode for the trget proessor ARM7. The figure 1 illustrted the struture in ontrolling eletro-hydruli motor system nd the grphi interfe of the ARM7 system for suh systems. The test rig of embedded ontroller onsists of hydruli embedded ontroller, proportionl vlve, vlve mplifier, nd rotry hydruli motor whih oupling with lod. Figure 1: Struture eletro-hydruli motor system nd the grphi interfe 35

2 For performne evlution, the mesuring motion profile of rotry motor employ n optil enoder nd DAQ rd. ARM7 embedded ontroller is the ontrol system s hert. It n red the input speed from touh sreen, disply perentge Pulse Width Modultion (PWM) in double oils of hydruli vlve nd lso n interfe user with setting prmeter to ompenste non-liner hrteristi of hydruli system (rmp nd ded bnd). Speed nd diretion of the hydruli motor re ontrolled by ARM7 proessor inputting timing pulse signls to its drive vlve mplifier. Hydruli motor rottionl speed is diretly proportionl to the width of pulse signl, whih mens the higher width of the pulse signl, the fster motor rotte speed. As show in figure 2, the bidiretionl vlve mplifier (298), will require PWM nd logi signl input in order to ontrol the speed motor nd diretion. This iruit n drives two oil of proportionl vlve with urrents up to 2 Amp. motor ontrol system pproximtion of the reltionship between the lod differentil pressure nd the input urrent to the proportionl vlve hs been derived to be: Figure 3: speed ontrol hydruli motor P ( K v I( S 2 2Ds ( ) 1 (1) In whih P is lod differene pressure, I is input C urrent K is vlve gin, is vlve nturl v frequeny, nd D is vlve dmping rtion. The torque on the hydruli rotry motor is given by; T (2) In whih, T is motor torque, nd is visous dmping is lod inerti, ( S) P ( S) ( V s 1) (3) Figure 2: The vlve mplifier with Mth Modeling of Hydruli Motor Control In this setion, we desribe mthemtil modeling of hydruli motor ontrol system. In figure 3, the system onsists of model behvior of proportionl vlve, eletroni drives, nd hydruli tutors. A ommon form of trnsfer funtion of hydruli The following eqution is vlid for the mplifier whih should provide DC urrent into the proportionl vlve Ie( Ks, K U ( 1 s 1, R R (4) 36

3 In whih, I, e U, R nd is proportionl vlve mplifier output urrent, voltge, resistne, nd indutne respetively. From eqution 1-4, the trnsfer funtion of hydruli motor drive n be express is: ( K s U ( s 1 s ( ) 2 Kv 2Ds 1 ( V (5) s 1) And the blok digrm of eqution 5 is show in figure 4. 3 Struture of Embedded Controller The inresing use of eletroni ontrol units in hydruli pplitions hs used n inresing need for onsidertion of the embedded ontrol system nd its implementtion in whih mny future diretions re surveyed in [4-6]. The struture progrmming of proportionl vlve ontroller in this reserh is shown in figure 4: The embedded proessor, PC2378 is Philips s proessor hip, whih bses on the ARM7 ore. PC2378 inludes PWM modultor, digitl IO, nd 16-hnnel 10- bit A/D onverter. A/D in ARM proessor smples ontrol signl from oystik to regulte speed by using it outputs PWM signl to ontrol proportionl vlve fter ompensted non-liner hrteristi nd one bit of digitl output is used to ontrol the diretion of hydruli motor vi vlve mplifier, 298. The setting ompensted prmeters of proportionl vlve ontroller suh s ontrol rmp, ded bnd, nd frequeny ould be set by the touh- sreen mn-mhine interfe, so s to the ontroller n be pplied in different types of proportionl vlves nd motor. Figure 4: The blok digrm of hydruli motor ontrol system Figure 5: The embedded ontroller grphil progrmming 37

4 In this projet, bview progrmming uses to design hydruli embedded ontroller tht inorportes with PWM, A/D, output logi signl ontrol proessing, nd ontrol nlysis pbility. Unlike other high-level progrmming development tools, bview Embedded Development Module n provide delivers full-funtion grphil lnguge for embedded softwre design from ontrol lgorithm to implementtion trget embedded ARM7. The implement softwre ws built on plugin frmework of hydruli motor ontrol with n desribe their entire pplition grphilly. The figure 5: illustrtes the hydruli motor ontrol frmework with grphil progrmming. Figure 7: The experimentl test rig 4 Simultions nd Experimentl Results In order to test the performne nd funtion bility of the new developed embedded for future motor hydruli ontroller. The Simultion nd experimentl test were rried out with speed ontrol to verify the ontroller performne. Speed ontrol simultion experiment using hydruli motor hd been employed by unified ontrol blok digrm s in figure 3. Figure 8: The Experimentl result Figure 6: The simultion result Figure 6. shows the simultion results hydruli motor ontrol. The plotted ginst the tul speed output of the eletro- hydruli motor nd time. This n be observed in the se of when the system ws ompensted with non-liner prmeter (rmp nd ded bnd). Its dynmi output n provide the stisfied response (smll jerk nd stedy stte error). In experimentl test rig, the embedded ontroller struture is presented in figure.7. For the experiment result shown in Figure 8, the speed of motor hydruli ontroller ompensted with non-liner prmeters n yield good performne. 5 Conlusions New embedded ontroller of hydruli motor ws presented where ARM7 miroontroller nd grphil progrmming with hrdwre drivers were developed together. The tutor relizes ontrol of speed nd diretion ontrol with ompensted nonliner funtion mking it stisfy dynmi response. The ompensted funtion n be setting vi mn-mhine interfe(touh sreen). This tutor system is expeted to ply gret role in mny different industril res espeilly in hydruli mnmhine intertion pplition. Further work will fous on the ontrol lgorithm of intelligent ontrol in embedded ontroller tht n provide better performne thn this proess. Referenes [1] D. Grgi nd K. Srinivsn Applition of Nonliner Adptive Control Tehniques to n Eletrohydruli Veloity Servomehnism IEEE Trnstion on Control System Tehnology, Vol. 12, No. 2, Mrh,

5 [2] W. Xiojing,. ihi, M. Yuhu,. Shngyi QFT Robust Control of the Continuous Rotry Eletro- Hydruli Servo Motor Interntionl Symposium on Systems nd Control in Aerospe nd Astronutis, [3] D.ovre, M. Kstrev,md S. Ulg Eletrohydruli lod sensing with speedontrolled hydr uli supply system on formingmhines Int Adv Mnuf Tehnol [4] K. rz6n, A. Cervin: "Control nd Embedded Computing: Survey of Reserh Diretions". In Pro. 16th IFAC World Congress, Elsevier, uly [5] A. Fudzi, Design nd Control of New Intelligent Pneumti Cylinder for Intelligent Chir Tool Applition 2009 IEEE/ASME Interntionl Conferene on Advned Intelligent Mehtronis [6] Mrti, P; Velso, M; Fuertes, ; Cmho, A;uttzzo, G Design of n Embedded Control Systems bortory Experiment IEEE Trnstions on Industril Eletronis, Volume: PP, Issue: 99 39