Study On Car's Semi-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.The aim of semi-automatic gearshift system is to solve the problem .The system can reduce driver's labour intensity effectively and increase his safety.Moreover,it is cheaper than automatic transmission and can get population in bus.Based on the original manual mechanical transmission, the system integrates electronical technology and mechanical design ,exerts their advantage, and utilizes method of the electronic pneumatic shift to complete the semi-automatic operation.The system is composed of manipulationl and execution.The former is in charge of collecting handle signals and codes them into commands which are transmitted to execution machine's MCU by CAN-bus.The MCU shifts according to the accepted signals,current car's speed and engine's rotate speed.The material action is carried out by corresponding cylinder that is controlled by MCU ,which supplys power or not for electromagnetic valves .Since one reach of cylingder is connected with gearshift axes, cylinder's action can drive it.This thesis includes the execution system's macro-design ,hardware, software and the CAN-bus communication,etc.The thesis firstly explains semi-automatic gearshift principle , introduces system's every section, the execution machine's actions ,the accelerograph's control,CAN bus communication protocol ,etc. In order to improve anti-jamming capacity, the system adopts a series of measures.