Study On Car's Automatic Gearshift Principle And Development Of Execution System

With the development of automobile industry, people bring forward higher request to function and performance of vehicle. Owing to most of buses in city are equipped with manual transmission and the distance between the bus stops is short, driver has to shift frequently and can be tired easily. Improving driver's steer is cared by the traffic department and carrying company. Using the study of the research experience in abroad for reference, according to our national actual circumstance, we developed an automatic transmission system that has the good function price ratio.Based on the original manual mechanical transmission, the system integrates electronical technology and mechanical design ,exerts their advantage, utilizes method of the electronic pneumatic shift to complete the automatic operation, and use the proportion electro-magnet instead of clutch treadboard . The system is composed of manipulation and execution. The former is in charge of collecting car's speed, engine's rotate speed and handle signals which are transmitted to execution machine's EPU by CAN-bus. EPU controls clutch, accelerograph and cylinder how to work.The thesis first explains automatic gearshift principle ,and then designs the execution system's macro-design ,hardware, software and the CAN-bus communication, and achieves the intelligent control of clutch and accelerograph. Fuzzy-PID complex control strategy has been adopted in this paper just make use of quick dynamic response, small overshooting, and high accuracy of PID control strategy. Different reasonable strategy is chosen for different errors scope. In order to improve anti-jamming capacity, the system adopts a series of measures.