基于双维度搜索的地下自主铲运机最优转弯轨迹规划

提出了一种基于双维度搜索的实时轨迹规划方法，用来解决自主地下铲运机转弯轨迹规划问题。该方法是一种结合采样思想和最优化算法的复合轨迹规划方法，包含三个主要步骤:基于双维度搜索策略的优化模型参数生成，基于二次规划的轨迹计算，以及基于约束检查的最优轨迹确定。该方法新颖之处在于提出的基于转弯区域行驶时间和里程的双维度搜索策略，以及基于平稳目标的轨迹最优化模型，可根据弯道区域入口速度和位置，快速生成纵横向都有最优性保证的最优轨迹。该方法结构简单、易于实施，可通过关键参数的调整满足控制器对轨迹生成速度的实时性要求。基于该轨迹规划方法的特点，使其不仅适用于实时轨迹规划，还可为未来智慧矿山的智能管控与优化调度提供底层约束。多组算例验证了该方法的有效性和优越性。 

Optimal turning trajectory planning of an LHD based on a bidimensional search

To solve the problem of smooth turning of an autonomous underground load-haul-dump loader (LHD), in this paper, a method for turning trajectory planning of an LHD was proposed. This method is a type of hybrid trajectory planning method based on a bidimensional search. According to the characteristic of the problem, the longitudinal and lateral decomposition method was applied, and the basic algorithms are a sampling method and an optimization algorithm. The algorithm consists of three main steps that are parameter generation of the optimal model based on a bidimensional search strategy, trajectory calculation based on quadratic programming models, and determination of the optimal trajectory based on an articulated angle and collision avoidance constraints check. The novelty of this method lies in the proposed two-dimensional search strategy and trajectory optimization models. The two dimensions are the driving time and mileage of the trajectory in the turning area; the trajectory optimization model is based on the quadratic programming that can quickly generate the optimal trajectory in both dimensions according to the turning area entering speed and position of the LHD. This trajectory planning method is simple in structure and easy to implement. Moreover, it can satisfy the real-time requirement of the controller on the trajectory generation time by adjusting the key parameters. Based on the characteristics of the trajectory planning method, it is not only suitable for real-time trajectory planning but can also provide basic constraints for intelligent control and optimal scheduling of intelligent mines. A series of case studies was conducted to show the effectiveness and superiority of the proposed method. The case studies show that the optimal trajectories according to different entering speeds and positions can be obtained through the proposed method. A prototype experiment was performed to show the feasibility of the proposed trajectory planning method. This method generates trajectories that are easy to track and control because the velocity, articulated angle, and angular velocity change gently.