拖拉机自动导航摩擦轮式转向驱动系统设计与试验

针对农机导航系统中使用传统拖拉机前轮转向驱动子系统机构复杂、装卸不便等问题,设计了一种摩擦轮式转向驱动系统。摩擦轮式转向驱动系统主要由驱动装置和相匹配的自适应模糊转向控制器组成。驱动装置采用平行四连杆机构以实现工作模式的快速切换,使用夹持固定方式实现便捷装卸。搭建了试验台架以获取摩擦轮驱动装置的滑移特性数据。同时设计适用于该驱动装置的自适应模糊转向控制器,基于液压系统离散传递函数和滑移特性数据建立了驱动系统递推仿真模型,采用该仿真模型构建遗传算法参数优化器对控制器参数进行在线优化。进行了仿真模型验证试验、遗传算法参数优化器性能对比试验和驱动系统性能试验,结果表明:仿真模型与实际系统基本一致;经过遗传算法参数优化后控制器阶跃响应上升时间减少15%,稳态误差达到3%标准所需调节时间减少29%,消除了振荡现象;所设计驱动系统的20°阶跃响应平均绝对稳态误差为0.197°,平均上升时间为2.0 s,稳态误差达到3%标准的平均调节时间为2.4 s,拖拉机前轮控制效果良好。应用试验表明驱动系统能基本满足拖拉机配套2BFQ-6型油菜精量联合直播机机组自动导航作业要求。

Design and Experiment on Automatic Steering Control System of Friction Drive for Tractor

An automatic steering control system of friction drive for tractor was designed to solve the problem that traditional automatic steering control system was too complex to be installed on 2BFQ-6 type direct seeding combined dual purpose planter. A four connecting rods parallel institutions was used to develop the steering control device of friction drive for achieving fast mode switching. Meanwhile, the friction drive was simple in operation and convenient in installation by using the clamping installation method. The discrete simulation model of tire steering maneuver was established based on slip characteristics of the device. The simulation model was adopted to design the genetic algorithm optimizer, which could optimize the controller parameters online. The self adaptation controller was adapted to control the automatic steering device of friction drive. The experiment on LX854-DFH tractor was used to analyze the performance of genetic algorithm optimizer. The experimental results showed that rise and regulation response time of the genetic algorithm optimization controller was decreased by 15% and 29% compared with the fixed parameter controller, respectively. The measured 20°step responses indicated that the average regulation time was 2.4s, the average absolute steady state error was 0.197°, and there was no steady state oscillation, when the experimental results were recorded. The automatic steering control system of friction drive could be applied to control nosewheel steering turning of 2BFQ-6 type direct seeding combined dual purpose planter for rapeseed.