农业机械学报2025，Vol.56Issue(10)：321-331,11.DOI:10.6041/j.issn.1000-1298.2025.10.027
基于Hybrid A*与最优控制的农机精准进田转场轨迹规划方法
Hybrid A* and Optimal Control-based Trajectory Planning Method for Precise Field Turning of Agricultural Machines
摘要
Abstract
In narrow farm roads,the planning of farm machinery movement trajectories affects the smoothness of the driving trajectory,as well as the quality and efficiency of field operations.Aiming to address the current issues in farm machinery path planning-such as large trajectory curvature,insufficient smoothness,and imprecise speed planning at narrow turns,which hinder optimal tracking performance,a method for precise farm machinery movement trajectory planning was proposed based on Hybrid A*and optimal control.By obtaining the prior grid map of the field entry,the initial pose,and the target pose,the Hybrid A*algorithm was used to obtain the optimal or near-optimal field entry path that satisfied the agricultural machinery's kinematic constraints.Time information was assigned to path nodes,and initial solutions required for solving nonlinear problems were obtained through data preprocessing.Using the optimal control problem method,a multi-objective cost function was established under multiple constraints,including agricultural machinery kinematic constraints,two-point boundary value constraints,dynamic constraints,and obstacle avoidance constraints,to achieve the objectives of shortening transfer time,improve agricultural machinery maneuverability,and enhance trajectory smoothness;the optimal control problem was converted into a nonlinear programming(NLP)problem and solved by using a nonlinear solver to obtain the agricultural machinery field entry and exit trajectory and velocity sequence.Using the Yanmar VP6E rice transplanter as the experimental platform,simulations and real-vehicle experiments were conducted in two scenarios:the agricultural machinery head facing away from the field access channel and the head facing toward the field access channel.Experimental results showed that the average trajectory curvature was 0.231 2～0.251 7 m-1,indicating good trajectory smoothness consistent with vehicle kinematic characteristics.In the trajectory tracking real-vehicle experiments,the average absolute lateral deviation was from 1.56 cm to 2.59 cm,the average absolute heading angle deviation was 0.97° to 1.54°,the maximum absolute speed deviation was 0.058 m/s to 0.102 m/s,and the average absolute speed was 0.454 m/s to 0.528 m/s.Therefore,the rice transplanting machine effectively tracked the trajectory generated by the trajectory planning method,enabling precise and rapid field entry and exit on narrow farm roads.关键词
精准转场/轨迹规划/最优控制/Hybrid A*/非线性规划/轨迹跟踪Key words
precision transit/trajectory planning/optimal control/Hybrid A*/nonlinear programming/trajectory tracking分类
信息技术与安全科学引用本文复制引用
迟瑞娟,付国辉,马悦琦,班超,苏童,陈嘉翊,李知旻..基于Hybrid A*与最优控制的农机精准进田转场轨迹规划方法[J].农业机械学报,2025,56(10):321-331,11.基金项目
国家自然科学基金项目(52172396) （52172396）
