Research and Implementation of Tractor Power Shift Clutch Control System

Transcription

1 Reserch nd Implementtion of Trctor Power Shift Clutch Control System Chengjun Li, Meicong Ke nd ouyu Wu School of informtion engineering, Wuhn University of Technology, Chin Abstrct. Applying power shift control technology on trctor cn improve the power, economy nd driving comfort of trctor. The seprtion nd enggement control of clutch in trctor power shift trnsmsion system the key fctor to optimize the qulity of shift. Through mny experiments nd tests, n electronic control unit bsed on MC9S1 ws developed, nd n effective clutch control strtegy ws put forwrd, which improved the jerk of power shift nd shortened the ger shift time. 1 Introduction The power shift trctor dopts electronic control system to simplify the complicted opertion process to simple push-button opertion, gretly reducing the driver's control difficulty nd lbor intensity, nd improving the qulity of work, so s to improve the work efficiency. The engging lw of clutch one of the key technologies of trctor power shift. The utomtic clutch bsed on the trditionl mechnicl clutch nd equipped with n electronic control system, which uses modern electronic technology to relize the utomtion of clutch mnipultion. When shifting, the driver presses the shift button, nd the clutch utomticlly completes seprtion nd enggement. Anlog sensor input signl Digitl sensor input signl Processing circuit Processing circuit Power Supply MC9S1 Solenoid vlve drive circuit Proportion l vlve On-off vlve CA communictio n module Design of electronic control system.1 System overll design Electronic control unit the core of the whole control system. Tking MC9S1 s microcontroller, the informtion of high nd low ger sensors (digitl quntities) nd clutch trvel sensors (nlog signls) extrcted nd nlyzed, dt processed by softwre, nd clutch trvel monitored ccurtely. According to the feedbck informtion of severl sensors, the electro-hydrulic proportionl vlve nd on-off vlve re hydruliclly controlled, nd the enggement speed of the clutch precely controlled with proper clutch enggement lw. Combined with the clutch trvel, the clutch speed chnged in rel time, nd the movement lw of the clutch effectively controlled so tht the ger shift stedy nd fst. The hrdwre system digrm shown in figure 1. Figure 1. System hrdwre circuit digrm.. Clutch control principle Dplceme nt sensor Clutch ction Anlog to digitl conversion Hydrulic cylinder ction Figure. Clutch control schemtic. MC9S1 Proportion l vlve (D1) On-off vlve (C1 C) The ction of the clutch ccomplhed by the clutch hydrulic cylinder. As shown in figure, electronic control system nlyzes hydrulic cylinder dplcement The Authors, publhed by EDP Sciences. Th n open ccess rticle dtributed under the terms of the Cretive Commons Attribution License 4.0 (

2 MATEC Web of Conferences sensor in rel-time, through the on-off vlve nd proportionl vlve control to chieve the hydrulic cylinder stroke control nd speed control, nd finlly relize the clutch movement control. The physicl digrm of the hydrulic cylinder nd the dplcement sensor shown in figure. TCU(Trnsmsion control unit) detects the output signls of ech sensor in rel time. When the TCU obtins the shift signl, the processor sends out n ction instruction to turn on the clutch solenoid vlve C1 so tht the hydrulic cylinder rpidly drives the clutch to be rpidly seprted. When the TCU obtins tht the clutch completely detched, the TCU closes the clutch solenoid vlve C1, leving the clutch in stte of seprtion. See figure 4.. Clutch enggement control Figure. The physicl digrm of the hydrulic cylinder nd dplcement sensor. Clutch control strtegy Clutch control strtegy determines the qulity of shift, nd it the key nd difficult point to relize power shift. Through the clutch seprtion nd joint control, it cn shorten the shift time, reduce the shift jerk, nd improve the shift-feel. The speed of the engging or dengging of the clutch cn be relized by the control of the proportionl solenoid vlve nd the on-off vlve by the electronic control unit. Clutch control strtegy divided into two prts: clutch seprtion control nd clutch enggement control..1 Clutch seprtion control Shift signl The clutch solenoid vlve C1 opens The clutch enggement lw directly ffects the overll shift qulity. The "fst - slow - fst" clutch enggement control strtegy cn effectively improve the shift qulity, referred to s "two fst nd one slow". In the clutch enggement process, the clutch enggement control divided into three modules, nmely, hlf joint front, hlf joint point nd hlf joint behind. The so-clled "clutch hlf joint" mens the hlf linkge. The clutch engged, but it not fully engged. Tht to sy, the hlf joint point tht the vehicle body bout to get enough output torque, nd the vehicle body in criticl stte tht will not move. The clutch rpidly pproching the hlf joint before the semi junction, which "one fst". After the hlf joint, the clutch quickly nd completely engged to shorten the ger shift time, which "two fst". At the hlf joint point, the system controls the flow of the proportionl vlve so tht the clutch engges slowly, ensuring the smoothness of the shift, which "one slow". So prece control of "two fst nd one slow" the key nd difficulty of clutch enggement control. The totl clutch trvel 50mm.After mny experiments nd tests, the clutch hlf joint point between 0-40mm.Therefore, in clutch enggement control process, it should be gurnteed tht during the trvel 0-40mm, clutch slowly engged. The engging time bout 800ms.The digrm of clutch trvel nd speed shown in figure 5. V(m/s) Clutch quick seprtion Are the clutch completely seprted? Return Figure 4. Clutch seprtion control flow chrt. During the ger shifting process, the power interruption time should be reduced s little s possible in order to void excessive power losses which Cuses the vehicle speed to fll too much. Therefore. The clutch seprtion process should be completed quickly S(mm) Figure 5. Reltionship between clutch enggement speed nd stroke. When the TCU obtins the clutch enggement signl, the TCU sends control signl to open the clutch solenoid vlve C, nd controls the proportionl vlve D1 to output lrger flow, nd the clutch enggement speed v 0.15m/s. At the sme time, the nlog sensor 1

3 detecting the clutch trvel position, nd the TCU processes the cquired nlog dt by mens of softwre (seeking vrince nd verge vlue) to obtin the rel-time trvel of the clutch. When the clutch trvel pproching 0mm, the TCU sends control signl to mke the proportionl solenoid vlve D1 output smller flow, nd the clutch enggement speed v 0.015m/s; When the clutch trvel mesured to be 40mm, the TCU controls the flow of the proportionl vlve gin, nd the clutch enggement speed v chnged to 0.m/s; When the clutch detected fully engged, the TCU closes the solenoid vlve C nd the proportionl vlve D1 to complete the enggement of the clutch. The process shown in figure 6. enggement signl C open D1 control speed v1 solenoid vlve C 5-61 proportionl vlve D Experimentl evlution index The experiment evlution index contins two prts:shift jerk j nd totl shift time t. Shift jerk j expressed s follows: d d v j (1) dt dt v trctor speed; trctor longitudinl ccelertion. The Germny recommended vlue of jerk : j 10m / s ; The Chin recommended vlue : j 17.64m / s. Totl shift time t expressed s follows: t t t t () b c Clutch trvel hs reched 0mm? D1 control speed v Clutch trvel hs reched 40mm? D1 control speed v t clutch seprtion time; t b block time; tc clutch enggement time; In order to shorten the totl shift time, the clutch seprtion time cn coincide with the block time. Becuse t, totl shift time t b t t t c () As the "two fst nd one slow" clutch enggement control strtegy, clutch enggement time divided into three prts: t c t t t (4) c1 c c Is the clutch fully engged? return tc1 clutch first segment quick enggement time; t c clutch second segment slow enggement time; t c clutch third segment quick enggement time. Therefore, the totl shift time t t t t t (5) c1 c c Figure 6. clutch enggement control flow chrt. 4 Experiment nlys 4.1 Experimentl conditions It necessry to ensure the stbility of the hydrulic oil nd solenoid vlve. Their experimentl conditions re shown in tble 1. The whole trctor performnce in good condition, the experimentl rod stndrd leveling cement ground. Tble 1. Experimentl conditions oil pressure 1.0MP oil temperture 5-57 solenoid vlve C Experimentl dt nlys For the relibility of the dt, the following experimentl dt re collected from two to three ger clutch first segment quick enggement Figure 7. Clutch first segment quick enggement time.

4 MATEC Web of Conferences clutch second segment slow enggement enggement time t c ms,the men vlue of clutch quick seprtion time t 9.96 ms.so the totl shift time t ms. 700 Figure 8. Clutch second segment slow enggement time 60 clutch third segment quick enggement Figure 9. Clutch third segment quick enggement time Figure 10. Clutch seprtion time Figure 11. Totl shift time. clutch seprtion totl shift Fig.7-11 shows the clutch enggement nd seprtion of ech prt time. The men vlue of clutch first segment quick enggement time t c ms,the men vlue of clutch second segment slow enggement time t c ms,the men vlue of clutch third segment quick Figure 1. The mesured jerk of the ger shift. Fig.1 the mesured digrm of the jerk of the trctor, nd the highest bsolute vlue of the jerk 9. m / s. The results show tht the clutch enggement lw dopts the "two fst nd one slow" control strtegy, which cn effectively reduce the shifting sense of frustrtion nd improve the totl shift time. 5 Conclusion 1) The key problem of trctor power shift technology put forwrd, tht, the seprtion nd enggement of clutch. ) Through mny experiments nd tests, n electronic control unit bsed on MC9S1 developed, nd the "two fst nd one slow" clutch enggement control strtegy put forwrd. ) Through the loding test, the correctness of the "two fst nd one slow" clutch control strtegy verified, the totl shift time shortened to ms, nd the shift jerk improved to 9. m / s. References 1. Liu, Jiguo, et l. "Study on Shifting Control Strtegy for Trctor AMT System." Agriculturl Equipment & Vehicle Engineering 7(014).. Sitou, oshitmi,. Isono, nd. Suzumur. "Electroniclly controlled clutch enggement speed correcting for n utomtic trnsmsion system." US, US Ling, Ling, Z. S. Chen, nd.. Luo. "Study on Control Process of Automtic Mechnicl Trnsmsion System for Pure Electric Bus."Applied Mechnics & Mterils 0-(01): Go, A., Z. Fu, nd W. Zhng. "Fuzzy shift schedule of utomtic mechnicl trnsmsion for trctors." Trnsctions of the Chinese Society for Agriculturl Mchinery 7.11(006):1-4. 4

5 5. Ot, Atsuo, S. rit, nd T. Msud. "Shift control unit of electric-power sst trnsmsion." (000). 6. itsche, Mrtin, nd A. Englch. "Method nd pprtus for ger shifting control with improved shift qulity during ger shifting." US, US Li, Guozheng, nd. Tn. "Reserch of utomtic gershift control technology for trctor mechnicl ger-box." Journl of Chin Agriculturl University 9.(004):