| The automation of automobile transmission is one of the cores of automotiveelectronic technology. With the development of economy and the needs of people'slife, the number of unskilled drivers is increasing. Thereby, automatictransmissions become one important direction of improving automobile structure.Automated Mechanical Transmission (AMT) is a high-tech product integrated withthe microcomputer control technology and technologies of mechanics, electronicsand hydraulic pressure, which is developed from traditional shaft manual gearboxand applied electronic technology and the theory of automatic transmission. Theconventional manual transmission has high efficiency, low cost and simplestructure. They are also used extensively. Automated mechanical transmissionholds the merits of the conventional manual transmission, and became popularincreasingly due to easy operating, good economy and comfortable sitting anddriving security. The AMT plays an important role in automated transmissions.Having high ratio of the performance to cost, it is suitable for the situation of ourcountry. Recently, the AMT automobile with higher shift quality, drivability andenvironmental safety has been required by demanding customers. All these factorsgive the automotive industries an increasing interest in AMT vehicles, which canbe observed. Moreover, AMT are extensively used in racing cars and modernhybrid electric vehicles.1. The conception and idea of AMTThe AMT can be actuated by electrical-hydraulic, electrical-pneumatic orelectrical way. The electrical-hydraulic way is the most. The AMTelectrical-hydraulic transmission control system consists of passages and tubes withhigher pressure hydraulic oil. They are controlled by electronic solenoid valves ormotor operated valves. This is to achieve the required positions at each time whenthe clutch or gear changes. The valves are under the control of an electronic controlunit (ECU). The pressure replay controls the pressure in the hydraulic circuit whenit is changed by switching the pump's motor. The advantages of this system are thefast response movements and the high precision in positioning the actuators.The basic principle of AMT: in terms of the intension of the driver( acceleration pedal, stopping pedal, control stick) and the current status of thevehicle(engine speed, input shaft speed, vehicle speed and gear position), rest onsuitable control rules ( the rule of shift, detach rule of clutch etc.), through themechanism of fuel supply, clutch and shifting, AMT control the system of thedriveline together(engine, gearbox, clutch). It's working performances mainlydecided by control system. Along with the development of information technologyand intelligent control, gearshift control is becoming more and more intelligent.Gear shift not only meets with power and economy requirements, but also shiftscan be done according to the drivers'wish. Thereby, it's a developing trend ofautomatic transmission control technique to design and develop automatictransmission with higher intellectualize. Presently AMT runs into practical phase.Many AMT products have come into the market and won high praise overseas. Inchina, people also are trying hard to make it transit from lab prototype to product.2. Investigative purpose in this dissertationWith the development of automotive electronic technology, automatedtransmission has become standard fitting for car overseas. The technology ofautomated transmission has developed from family car to passenger car, to truck,etc. Domestic car has always fast developed, but, because of some problems, forexample, fund lack, backward productive crafts and technologies, it is a feasibleproject to implement AMT transformation for axis fixed transmission. The researchin this dissertation is the design of the military off-road vehicle AMT electroniccontrol system based on the above ideas.3. Main research workThe goal of this dissertation is to develop the software and hardware design ofthe military off-road vehicle AMT. The electronic control unit (ECU) of AMTcontrol system receives various parameters of vehicle according to the driver'soperation and the status of vehicle in form of electronic signals, such as controlstick, acceleration pedal,the engine speed, vehicle speed, and so on. Infineon'sC164CI microcontroller is used as the processor of the ECU. The ECU receivesinformation from analogue sensors and transfers it to computer software via A/Dconverters and I/O interface. In the ECU, the vehicle speed and the throttle positionsensors'data are used to determine the gear shifting point. After the data acquiringand processing, the control system judge the gear position which is suitable for thevehicle in accordance with the pre-established shifting strategy, and then decide toshift or not.The dissertation consists of six chapters. The main research work of it is as thefollows:3.1 The history of and the characteristics of three typical kinds of automatedtransmission are introduced. Moreover, the advantage and development of AMT arediscussed.3.2 The general design method of AMT control system. The working principle,the configuration and the utility of AMT control system are introduced. In the AMTsystem control strategy,clutch engagement strategies in the process of starting andshifting are elaborated, which are based on analyzing AMT's structure and workingprinciple. Moreover, optimal dynamics and economics shifting strategies aredesigned under different moving environment.3.3 The hardware design of the AMT control system. There're wide varietiesof hardware in the AMT, this section introduce the sensor, mechanism, themicroprocessor, input and output signal circuit that are used in the system.3.4 The software design on the AMT control system includes the softwaregeneral designing and the subroutine designing. In the software general designing,it explains the program structure and the convenience of using C language todevelop program. In the subroutine designing, according to the control method andshifting strategies, the subroutine designing and the code of control program of theAMT control system are finished.3.5 The development tools, environment and the debugging process of theAMT control system are introduced.4. ConclusionThis text doesn't do the further thorough research to the control algorithm ofthe implement mechanism and control system design now still exist some weakness.For example, its capability of anti-jamming is not high and its self-adaptationability is not strong. In addition, the real-time performance of the control algorithmalso needs to be verified and the design of the control system still has a very bigimprovement leeway. Moreover, what the system has completed are basal functionsof the AMT, its functions can be expanded and the simulation need to be furtherinvestigated. For example, we can add the automated fit to the driver characteristicand road characteristic, rationality of the system can be verified byhardware-in-the-loop simulation. In this way, we will make the whole AMT controlsystem more perfect. |
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