基于视觉的四轮驱动电动汽车转向控制方法研究.doc

基于视觉的四轮驱动电动汽车转向控制方法研究

硕士学位论文
MASTER’S DISSERTATION
论文题目基于视觉的四轮驱动电动汽车转向控制方法研究
作者姓名学科专业载运工具运用工程
指导教师副教授摘要
节能、环保及安全是现代汽车工业发展三大主题。面临21世纪能源及环境问题的严峻挑战,世界各国均将车辆节能、环保作为重要研究方向。其中,电动汽车是最受关注领域之一。与此同时,车辆安全性亦备受关注,而车辆操纵稳定性是其安全性重要内容之一。
为改善车辆操纵稳定性,四轮转向技术被应用到车辆转向系统中,该技术能够提高车辆低速时的机动灵活性,改善高速时的操纵稳定性。随着科学技术发展,机器视觉及各种新控制方法亦被应用于车辆上,以提高车辆行驶时的安全性。本文将机器视觉技术和四轮转向技术相结合,运用视觉信息实现四轮转向车辆前后轮转角分配,并对此种车辆进行仿真建模及分析,验证本文所用方法的有效性。
首先,介绍机器视觉技术中所用到的硬件设备及其与四轮转向技术结合后的运行原理。在引入车辆及轮胎标准坐标系基础上,建立四轮转向车辆二自由度动力学模型,并对其稳态响应及瞬态响应进行分析,为仿真模型建立及仿真结果分析奠定基础。
其次,设计车辆控制方法。本文将机器视觉获取的信息融入前馈控制器设计之中,保证车辆质心侧偏角较小且满足一定不足转向特性,并运用最优控制理论设计反馈控制器,实现对整车控制。
最后,建立整车仿真模型,对本文设计的前后轮转角分配方法及控制器进行仿真分析和验证。同时,将本文所用方法应用于不同转向方式车辆,进行仿真分析及结果比较。
关键词:电动汽车;四轮转向;机器视觉;目标函数;最优控制;仿真模型
Abstract
Energy-saving, environmental protection and safety are the three main themes of the modern automobile industry. Facing the serious energy and environmental challenge of the 21st century, vehicles energy-saving, environmental protection are an important research direction worldwide. The electric automobile is one of the most popular areas of concern Four-wheel steering technology has been applied to the vehicle steering system, in o- rder to improve vehicle handling stability, the technology can improve the vehicle maneu- vering flexibility at low-speed, improve handling and stability at high-speed. The bined machine visi- on and four-wheel steering, using visual information to achieve the allocation of vehicle front and rear steering, and took such vehicle modeling and analysis, to verify the validity of the methods used in the text.
Firstly, the text introduced operation principle bined hardware devices used in machine vision technology and four-wheel steering technology. Established two degrees of four-wheel steering vehicle dynamics model, the establishment of two degrees of freedom of the four-wheel steering vehicle dynamics model, and analyzed its steady-state and transient response, lay the foundation for establishing the simulation model