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基于改进NSGA-II悬臂式掘进机断面成形截割轨迹规划方法

Improved NSGA-II method for section forming trajectory planning of boom-type roadheader

  • 摘要: 悬臂式掘进机断面成形截割轨迹规划是实现自主截割的基础。针对当前悬臂式掘进机的轨迹规划方法对截割头尺寸和目标断面约束考虑不足,难以保证断面成形质量的问题,提出了一种基于改进带精英策略的快速非支配排序遗传算法(Nondominated Sorting Genetic Algorithm II,NSGA-II)的悬臂式掘进机断面成形截割轨迹规划方法。首先,建立悬臂式掘进机运动学模型,实现悬臂式掘进机、目标断面和巷道之间坐标转换。其次,构建截割头简化模型并建立目标断面约束模型,以此为基础设计机身位姿驱动下的截割空间,获得可行截割空间点集。随后,设计总截割轨迹最短与总转角最小的双目标函数,并将其转化为带邻接约束的双目标旅行者问题。总结断面成形截割过程的特点,设计邻接约束处理方法,采用深度优先搜索从种群初始化和遗传操作等对NSGA-II方法进行适应性改进,优化求解双目标旅行者问题从而生成可执行截割轨迹。最后,通过仿真与实验验证方法的有效性。结果表明:相比于原始算法,改进NSGA-II收敛速度提升了68.13%,总耗时减少了91%,同时总距离和总转角均有一定的提升;通过虚拟仿真实验开展非全断面成形截割实验,验证了不同机身位姿驱动下的截割轨迹有效性;通过对比规划轨迹与跟踪轨迹,发现截割轨迹跟踪效果良好,且最大偏差为23.879 mm,能够有效支撑自主截割控制。该方法能够满足当前断面成形截割轨迹规划需求,为进一步开展悬臂式掘进机自主控制提出了新思路。

     

    Abstract: The cutting path planning of boom-type roadheader is the basis of realizing autonomous cutting. Aiming at the problem that the planning trajectory is too simple to support the automatic cutting control effectively due to insufficient consideration of cutting head and target section constraints, a cutting trajectory planning method based on improved NSGA-II was proposed. Firstly, the kinematics model of boom-type roadheader is established to associate roadheader, target section and roadway to achieve a unified coordinate conversion benchmark. Secondly, a simplified model of the cutting head and a target section constraint model are constructed, based on which the cutting space driven by the fuselage pose is designed, and the feasible cutting space point set is obtained. Then, the bi-objective function with the shortest total cut path and the smallest total Angle is designed and transformed into a bi-objective traveler problem with adjacency constraints. The characteristics of the section forming cutting process were summarized, the adjacency constraint processing method was designed, depth-first search was used to improve the NSGA-II method in terms of population initialization and genetic manipulation, and the solution to the double-objective traveler problem was optimized to generate the executable cutting trajectory. The effectiveness of the proposed method is verified by numerical simulation. Compared with the original algorithm, the convergence speed of the improved NSGA-II is increased by 68.13%, and the total time is reduced by 91%. At the same time, the total distance and total Angle are improved to some extent. At the same time, the total distance and total Angle are improved to some extent. The experiment of non-full section forming cutting is carried out by virtual simulation experiment, which verifies the effectiveness of cutting trajectory driven by different fuselage positions and has higher forming quality. Finally, an experimental verification platform was built to compare the planned trajectory and tracking trajectory, and it was found that the tracking effect of the cutting trajectory was good, and the maximum deviation was 23.879 mm, which could effectively support the autonomous cutting control. This method provides a new solution for further developing cutting trajectory planning and autonomous control of section forming.

     

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