Design Of The Clutch Control System For Electric Automobile

As the gasoline automobiles are casing more and more problems, most governments and corporations focus on the development of electric vehicles. As one of the vital parts in electric cars, the clutch plays an important role in the work of electric car, such as in the field of power performance, economical efficiency, driving comfort and safety. Therefore, it is very important to develop the clutch control system in electric automobile.As the Modular Design is becoming more and more popular in automobile control system, the design of the clutch control system should follow this line. Also, the stroke of the clutch motor is short, the working time is limited and the working condition is complicated, all of these require that the clutch control system should perform well in position control.Firstly, this paper analyzes the combining process of the clutch in detail and finished the demand analysis of the clutch control system. According to the demand analysis, the hardwere and software control system are designed. This control system is based on the ARM-STM32 microcontroller which has plenty functions on chip. CAN bus is used to communicate with other systems. The usage of the STM32 and CAN bus could make the Modular Design available. The 12-bits A/D converting circuit could read the position and current data in precision and short time which is well fit for the control system. H-bridge circuit and opto-coupler are used to control the motor which needs high working current and low-interference.The software is designed on this hardware and it includes main background module, CAN communication module, motor control module and error handling module. The functions of the main background module are system initialization and host computer order processing. CAN communication module is responsible for massge receiving and sending. Using the PID algorithm and interpolation, the motor control module is in charge of motor controling. The PID algorithm is based on incremental method and the interpolation is combined with linear acceleration and deceleration. The error handling module is comprehensive and it consists of the position error, interpolation error and output error. The error handling module is well designed to make sure that it is safe to drive the car. The test on the real car proves that the clutch could work steadily, have high responding speed, long working life and generate low impact under this control system.