基于双切圆寻线模型的农机导航控制方法

Dual Circle Tangential Line-tracking Model Based Tractor Navigation Control Method

摘要:

针对油菜直播机组导航作业中田头换行、转弯等直线跟踪之间的衔接控制问题，设计了一种适用于2BFQ—6型油菜精量联合直播机导航的双切圆寻线模型控制方法。对初始偏差较大时拖拉机的寻线路径进行了定量分析，获得最优寻线路径的几何关系，依据该关系构建控制决策方法。所建决策方法根据拖拉机位姿状态选择相匹配的控制方程组，计算获得前轮转角以实现导航控制。进行了双切圆寻线模型参数仿真优化和性能与适应性仿真试验。使用该模型控制器进行拖拉机路面导航试验，结果表明：当行驶速度为0~7m/s，拖拉机与目标直线初始横向偏差为7m，初始航向偏角为90°时，控制器横向偏差响应的超调量不超过3%，上升时间小于14s，调节时间不大于19s，较纯追踪模型方法的超调量和调节时间更小；田间和路面试验结果表明：该模型控制方法对2BFQ—6型油菜精量联合直播机导航作业过程中的对行播种起始位姿调整和套行作业自动转弯操作具有指导价值。

Abstract:

A dual circle tangential line-tracking control method was designed to solve the problem of linear tracking control when navigation system of 2BFQ—6 type direct-seeding combined dual purpose planter for rapeseed working near the boarders of a field. Firstly, a geometric relation formula of optimal connecting linkage was found by quantitative analysis of the far targeted line searching path. Then the method of dual circle tangential line-tracking was constructed by the geometric relation formula, which created decision-making. According to the position and orientation of the tractor, the matching control equations were selected by decision-making, and its calculations were used for tractor navigation control. Hence, a navigation system simulation model was established, which was used to achieve the purpose of optimizing model parameters and verifying the model performance. Path experiments were carried out with the navigation system of tractor. Experiments result showed that the overshoot of lateral deflection error response was less than 3%, rising time and settling time of the response were smaller than 14s and 19s, respectively. When the speed of tractor was 0~7m/s, the initial lateral deviation error of the tractor center between the target line was 7m and the initial course deviation error was 90°. When it was compared with the method of conventional pure pursuit navigation model, the dual circle tangential line-tracking control method resulted in less values of overshoot and settling time. Based on the results of path tracking experiments and field experiments, the dual circle tangential method could be applied to operation of lane-changing and turning of 2BFQ—6 type direct-seeding combined dual purpose planter for rapeseed.