Research And Application Of Electronic Control Unit Of Subcompact Automatic Clutch

Based on the traditional dry friction clutch of Subcompact, this paper reveals the design of Automatic Clutch System (ACS), aiming to control the clutch automatically without pedal. Manual motor possesses many advantages such as low cost, simple structure, high transmission efficient and so on, and automatic car can be controlled easily. ACS contains both their strengths so that it is a product which can fit the low cost Subcompact and satisfy Chinese consumers.The paper mainly discusses the following contents:the structure and principle of the automatic clutch's control system, the hardware system's design of the electronic control unit, the software system's design of the electronic control unit and the analysis of launch control.The control system used permanent magnet DC motor to drive the clutch's actuator, transforming the motor's orbiting to linear motion by screw and nut mechanism, so that the clutch can release and engage automatically. Using the AVR single chip as the MCU and it's abundant 10 function, the electronic control unit was designed. It transferred signal by K line and kinds of sensors, displayed data with ZLG7290 and controlled the motor by PWM. PWM was supplied by BTS7960 which is high-power and intelligent. Composed a H-bridge by two chips, the unit could manipulate the motor's starting, inversion and acceleration-deceleration. The motor's movement reflects the actuator's motion so as to realize the purpose of the clutch's automation.For convenience of compile and debug, the software system used modular design to achieve the functions which were needed by hardware platform.These modules includes key module, speed regulation module, display module and acquisition of signals. There are two kinds of acquisition:one is analog signals transferred by sensors which are input by ATmegal6's AD ports and the results are filtered by the program; the other is digital signals deliverred by K line. After researched the KWP2000's structure and resolved the matters of timing and arbitration during realization process, the unit of ACS can communicate with ECU normally by K line.Lastly, taking launch control for example, the paper brings up the strategy of launch control. Because of the clutch-engine system is complicated, the control strategy of the system is high qualified. The paper analyze the engaging process of the clutch and presents "fast-slow-fast" rule. At the base of the rule, the engine constant speed stratege is showed using throttle percentage and the rotatingspeed of the engine as the main parameters. Researching the method of fuzzy control, the paper puts forward partial fuzzy control strategy to reach the goal of launch control for throttle percentage, the engine speed's rate of change, the deviation between the target engine speed and the real speed and the displacement of the clutch as the parameters.