Design Of Vehicle Autopilot Control System

Vehicle autopilot is a kind of robot simulating human to drive based on automatic control technology. It can be fixed most of the cars conveniently and fast and intellectually control the running of them. Now, Autopilot research is already one of the main development directions of the intelligent vehicle, meanwhile, which has great significance in the automobile test and practical application.Autopilot control system was designed by using Freescale16-bit microcontroller as a core in this paper, which can let cars’steering wheel, gearshift handle, throttle, clutch and brake pedal, etc. finished coordinated operation through controlling actuating mechanism, and achieving transverse (direction) control and longitudinal (speed) control in a predetermined trajectory path. Finally, the automatic driving function is obtained. The main research content of this paper contains control strategy research, hardware circuit design, system software design and implementation, as follows:(1) In control strategy research respect, vehicle automatic driving control principle is analyzed and transverse and longitudinal control strategy models are established. Meanwhile, a modified algorithm of target distance selecting based on the control algorithm of "Target-track", which can reduce data computational complexity and get parameter values of transverse control and longitudinal control according to the control strategy model.(2) In hardware circuit design, according to the requirements of autopilot control system and performance index, this paper finished the hardware module design of control system under considering system hardware anti interference. The main research contents include the minimum system, input signal conditioning circuit, CAN node circuit, key-press and display circuit, data storage circuit and so on.(3) In system software design, system software is finished in the Code Warrior compiler environment. Moreover, the main body frame of software, the main realization process of each function module and the related program code are given out. Meanwhile, this paper transplants Embedded Real-time Operating System μC/OS-II into Freescale16-bit microcontroller to improve the stability of system software, confirming task priority according to task real-time, the system task partitioning and establishment is also completed under μC/OS-II.(4) In system implementation respect, real-time control and precision of the control system are verified through simulation test and real vehicle test, the experimental results show that this control system can achieve a predetermined trajectory automatic driving function, but the system still needs to be further improved.