北斗定位田间信息采集平台运动控制器设计与试验  

Design and experiment of motion controller for information collection platform in field with Beidou positioning

作　　者：丁幼春[1] 詹鹏[1] 周雅文[1] 杨军强[1] 张闻宇[1] 朱凯[1] 

机构地区：[1]华中农业大学工学院,武汉430070

出　　处：《农业工程学报》2017年第12期178-185,共8页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点研发计划项目(2016YFD020060602);湖北省技术创新专项重大项目(2016ABA094)

摘　　要：针对轮式田间信息采集平台在田间复杂环境下定速直线跟踪问题,设计了一种横向纠偏与纵向定速行走的运动控制器。控制系统采用低精度北斗定位模块、电子罗盘、旋转编码器、角度传感器获取田间信息采集平台的状态信息(包括位置、航向、速度、转向角)作为运动控制器的输入,通过构建的横向纠偏模糊控制器和纵向定速PID(proportion integration differentiation)控制器,实现行走过程中的横向纠偏和纵向定速行走。为获取更准确的位置信息,采用3个低精度北斗定位模块以边长1 m的等边三角形方式放置对数据求均值得到中心点定位数据的方法,将北斗接收模块的平均静态定位精度从2.06 m提高到了1.50 m,动态定位精度提高到0.78 m以内。信息采集平台田间试验结果表明:车体系统能按照规划的路径行走,在设定速度0.4 m/s时,纵向速度稳态误差小于7%,在外界扰动下响应调节时间小于3 s;以相同的速度行驶,初始横向偏距分别为1.4、2.0和2.5 m时,稳定跟踪需要的时间分别为11、15和25 s且稳定跟踪后最大横向偏距在0.31 m以内,满足农业田间信息采集的需要。该控制系统实现了信息采集平台在田间的定速直线跟踪和稳定行走,为其高效智能化作业提供了技术参考。With the development of precision agriculture technology, agricultural robots which improve efficiency and save labors for agriculture are used for information collection in field, instead of the traditional manual recording and observation. At home and abroad, most of navigation researches of walking platform meet the requirement of tracking precision. However, they mainly use RTK-DGPS （real time kinematics - differential GPS） positioning system, and it is so expensive that it restricts the large-scale promotion of automatic navigation of walking platform to some extent. Consequently, aiming at uniform speed and line tracking problem in complex field environment for information collection platform, a motion controller with transverse correction and longitudinal constant speed control was designed. This paper constructed motion control hardware system using information collection platform as the carrier, STM32F4 32-bit microcontroller was as the control center and multiple sensors were used for obtaining the vehicle status information, including 3D （three-dimensional） electronic compass, low precision Beidou module, rotary encoder and angle sensor. The working principle of the controller could be described as follows： Firstly, 2 points were chosen to determine tracking path. Then, the current position information and the heading angle of the platform in the field were obtained by Beidou module and electronic compass. They were used to calculate the lateral offset and course deviation, which were 2 inputs of fuzzy controller, and the output of fuzzy controller was got through designing control algorithm to control steering angle of front wheel. It ensured information collection platform to always track the goal line. Meanwhile, speed information of the platform was measured by the rotary encoder, which was the input of PID （proportion, integral, derivative） controller. It realized constant speed walking through speed feedback regulation. On the other hand, in order to improve the positioning precisio

关 键 词：农业机械 控制系统 导航 田间信息采集平台 运动控制器 定位精度 直线跟踪 

分 类 号：TP273[自动化与计算机技术—检测技术与自动化装置]