基于CAN总线的拖拉机自动导航系统转向控制策略研究

发布时间：2018-11-10 09:37

【摘要】：拖拉机自动导航技术是精细农业发展的关键技术之一。拖拉机自动转向技术作为自动导航技术的重要组成部分,与作业品质息息相关。本课题以搭载北斗卫星导航系统、智能终端及导航控制器的东风1004拖拉机为测试平台,开发了基于CAN总线的拖拉机自动导航系统转向控制器,并借此平台,进行转向控制策略设计及验证,主要以PID控制算法为基础,研究其改进控制算法,包括分数阶及智能PID控制算法,并通过仿真实验选取综合性能最佳控制算法,在进行转向系统硬件设计后,完成拖拉机自动导航系统的田间测试。本文的研究工作主要有以下几个部分:1.通过介绍国内外农业车辆自动导航系统研究现状、CAN总线在农业机械上的应用现状以及自动转向控制策略的研究现状,制定本课题研究的目标及技术路线。2.在对拖拉机自动导航系统组成及原理,尤其是自动转向系统功能分析的基础上,搭建了拖拉机动力学模型,并据拖拉机液压转向系统自动转向改装方案,建立了基于MATLAB/Sim Hydraulics仿真模型;通过理论分析,建立了基于传递函数的自动转向模型,并进行传递函数模型的优化。3.以自动转向PID算法为基础,对其技术改进算法进行研究,包括分数阶PID及智能PID算法,并利用搭建的仿真模型,初步验证自动转向控制算法控制效果。4.搭建自动转向控制策略的硬件验证平台,根据ISO 11783制定系统的通信协议;进行转向控制系统的硬件设计及软件设计。5.进行自动转向系统的安装与测试,完成转向控制策略的验证试验,测试结果表明,拖拉机行驶速度在4 km/h左右时,直线跟踪的横向偏差最大为2.8 cm,自动转向控制精度为2.5 cm,满足实际作业要求。
[Abstract]:Tractor automatic navigation is one of the key technologies in the development of fine agriculture. As an important part of automatic navigation technology, tractor automatic steering technology is closely related to operation quality. Based on the test platform of Dongfeng 1004 tractor with Beidou satellite navigation system, intelligent terminal and navigation controller, the steering controller of tractor automatic navigation system based on CAN bus is developed. The steering control strategy is designed and verified. Based on the PID control algorithm, the improved control algorithm, including fractional order and intelligent PID control algorithm, is studied, and the optimal comprehensive performance control algorithm is selected through simulation experiments. After the hardware design of steering system, the field test of tractor automatic navigation system is completed. The research work of this paper mainly includes the following parts: 1. This paper introduces the research status of agricultural vehicle automatic navigation system at home and abroad, the application status of CAN bus in agricultural machinery and the research status of automatic steering control strategy, and formulates the research goal and technical route of this subject. 2. Based on the composition and principle of tractor automatic navigation system, especially the function analysis of automatic steering system, a tractor dynamic model is built, and according to the scheme of automatic steering modification of tractor hydraulic steering system, The simulation model based on MATLAB/Sim Hydraulics is established. Through theoretical analysis, an automatic steering model based on transfer function is established, and the transfer function model is optimized. Based on the automatic steering PID algorithm, the improved algorithm is studied, including fractional PID and intelligent PID algorithm, and the simulation model is built to verify the control effect of the automatic steering control algorithm. 4. The hardware verification platform of automatic steering control strategy is built, the communication protocol of the system is established according to ISO 11783, and the hardware and software design of the steering control system is carried out. The installation and test of automatic steering system were carried out, and the verification test of steering control strategy was completed. The test results showed that the maximum transverse deviation of straight line tracking was 2.8 cm, when the tractor speed was about 4 km/h. The precision of automatic steering control is 2. 5 cm,.
【学位授予单位】：重庆理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S219

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