Study On The Application Of One-way Clutch In The Hill-start Assist System Of AMT

Since its inception more than half a century,AMT has never stopped the pace ofdevelopment.At first,it has barely changed the executive part of the transmission frommanual control to electro-hydraulic control,nowadays,it has turned to transmissionclutch and engine triple combine control.The control technology of AMT hasundergone enormous changes.As the technology blockade of the foreigncompanies,the AT that exactly made in China have less than10percent in themarket.The high price and the complex structures might restrict the development ofAT.Compared with AT,the simple structures,the low cost and the increasingly stringentemission standard made AMT which modified by manual transmission has excellentproduct succession become the best select for automobile manufacture.The DualClutch Transmission and the Sequential Gearbox used in Formula One cars whichwere very popular recently were belong to AMT.The economy of DCT and the powerof Sequential Gearbox were unreachable level for other transmissions.Therefore,AMTmust be a significant development direction of transmission in the future.Clutch engage control during the start-up section was the key part of entire controlprocess of AMT,and the difficult part.It relate to the usage of clutch and ridecomfortable.In the manual transmission vehicles,it required drivers combine operateclutch pedal,accelerate pedal,gearbox and parking brake at the same time,on thisbasis,it required drivers continuously adjustment operations rely to the changeableenvironment.However,in the AMT vehicles, ECU and TCU have to made decisiondepend on signals such as vehicle speed,engine speed,clutch output speed andaccelerate pedal angle.It even required to choose different control program byjudgment driver’s intent,how inconsiderable it is.Thus,as long as traditional PIDcontrol has no longer satisfied the requirements,the intelligent control has gradually attract researchers’ attention.In this paper,fuzzy control was adoption as AMT control strategy.Unlike formerlycontrol method,which continuously adjustment the engage volume by the angularvelocity of accelerate pedal in the start-up section,this only judgment drivers’ intent bythe angle of accelerate pedal to calculate the optimal control strategy.In thiscondition,the affect of tiny changes in operation could be minimize.When the driverintend to urgent start or abort start,he could continue depressed the accelerate pedal toa setted angle or just lift up his foot from the accelerate pedal.Based on that,this paperused a brand new type of start-up equipment with an one-way clutch instead oftraditional Hill-start Assist System.In the condition of one-way rotationtheory,one-way clutch could easily achieve the goal that not roll back when vehiclestart-up on a slope.Replace the electronic-hydraulic system by the pure mechanicalsystem,the new method greatly depress cost and improve the reliability.At last,this paper used Matlab/Simulink software created vehicle model,thensimulation contrary to different gradient(include downhill situation) and acceleratepedal angle that conducted two important evaluation index--impact and slidingfriction works.After analysis,they were basically meet the require.Because of theone-way clutch start-up assist system was still in the stage of theory testing rather thanpractice in real vehicle,its work results and usage were demanded more research.