基于履带式联合收获机转向特性的局部跟踪路径规划

为降低履带式联合收获机导航路径跟踪转向控制频率和提高控制系统的稳定性，提出了一种预瞄-切线局部跟踪路径动态规划算法。规划的局部跟踪路径由平滑连接的两段弧线组成，第1段圆弧由收获机当前位姿与1/2横向偏差线上的预瞄点确定，第2段圆弧由收获机在1/2横向偏差线的实际位姿与期望路径的几何关系确定；基于收获机实际转向运动特性建立了相适应的转向控制模型，左转、右转控制模型拟合的决定系数R2分别为0.978、0.980。田间直线导航跟踪对比试验表明：当前进速度为0.4、0.8m/s时，横向偏差的标准差分别为0.0489、0.0507m，航向偏差的标准差分别为3.94°、4.66°，转向控制次数分别为19、12次；与传统纯追踪算法相比，横向偏差的标准差分别减小19.04%、31.30%，航向偏差的标准差分别减小25.94%、9.16%，转向控制次数分别减少47.22%、42.86%。本研究可为履带式农机车辆导航控制器设计提供参考。

Local Tracking Path Planning Based on Steering Characteristics of Crawler-type Combine Harvester

To reduce the navigation path tracking steering control frequency of crawler-type combine harvester and improve the stability of the control system, an aiming-tangent local tracking path dynamic planning algorithm was proposed. The planned local tracking path consisted of two smoothly connected arcs, the first arc defining the aiming point on the line of 1/2 lateral deviation from the current position of the harvester, and the second arc defining the geometry of the desired path from the actual positioning of the harvester on the line of 1/2 lateral deviation. An adapted steering control model was established based on the actual steering motion characteristics of the harvester, with R2 of 0.978 and 0.980 fitted to the left-turn and right-turn control models, respectively. The straight-line navigation tracking comparison test in the field showed that the standard deviation of lateral deviation was 0.0489m and 0.0507m, the standard deviation of heading deviation was 3.94°and 4.66°, and the number of steering control was 19 and 12 when the vehicle speed was 0.4m/s and 0.8m/s, correspondingly. Compared with the conventional aiming pursuit algorithm, the standard deviation of lateral deviation was reduced by 19.04% and 31.30%, the standard deviation of heading deviation was reduced by 25.94% and 9.16%, and the number of steering control was reduced by 47.22% and 42.86%, respectively. The results can provide a reference for crawler-type agricultural vehicles navigation controllers.