Liu Zhi-Guang, Yang Hai-Nan, Wang Qin-Cong, Shi Yong, Zhao Jian
School of Control and Mechanical Engineering, Tianjin Chengjian University, Tianjin, 300384, China.
School of Electrical and Mechanical Engineering, GuangZhou City Construction College, Guangzhou, 510900, Guangdong Province, China.
Sci Rep. 2025 Feb 25;15(1):6727. doi: 10.1038/s41598-025-90822-6.
A four-wheeled robot can stride through longitudinal trenches to adapt to terrain challenges and effectively reach the target position in unstructured space, thus achieving navigation in rough terrain. Establishing a trajectory planning method to plan four paths simultaneously is necessary. Firstly, a grid map is based on the longitudinal trench terrain. Secondly, according to the robot's four-wheel size and chassis height, the robot can safely stand in the grid sequence. Finally, the minimum chassis and road height and the maximum roll Angle are added to the objective cost function of the traditional A* algorithm. An improved A* algorithm plans a four-wheel straddling path through the longitudinal ditch in the safe standing sequence. Simulation experiments prove that proposed method can effectively plan the four-wheel path on complex terrain. The planned path can be changed according to the adjustment of the weight values corresponding to the distance to the target, the minimum distance from the chassis to the ground, and the roll Angle. Such changes prove that the proposed method can effectively plan the path according to the actual situation, focusing on the speed (whether the path planning can be carried out) and the safety (whether the bottom dragging and rollover can be considered). The actual experiment proves that the robot can cross the longitudinal ditch in the form of left and right wheels. When the distance is about 10.5 m, the robot can pass through the longitudinal ditch quickly and safely in 19.8 s at a speed of 0.53 m/s, keeping the robot's tilt angle less than 20°.
四轮机器人能够跨越纵向沟渠以适应地形挑战，并在非结构化空间中有效到达目标位置，从而实现崎岖地形中的导航。有必要建立一种轨迹规划方法来同时规划四条路径。首先，基于纵向沟渠地形创建一个网格地图。其次，根据机器人的四轮尺寸和底盘高度，机器人能够安全地站立在网格序列中。最后，将底盘与路面的最小高度以及最大侧倾角添加到传统A算法的目标代价函数中。一种改进的A算法按照安全站立序列规划通过纵向沟渠的四轮跨越路径。仿真实验证明，所提方法能够在复杂地形上有效规划四轮路径。所规划的路径可根据与目标的距离、底盘与地面的最小距离以及侧倾角对应的权重值的调整而改变。这些变化证明，所提方法能够根据实际情况有效规划路径，兼顾速度（路径规划能否进行）和安全性（是否考虑底部拖拽和翻车）。实际实验证明，机器人能够以左右轮的形式跨越纵向沟渠。当距离约为10.5米时，机器人能够以0.53米/秒的速度在19.8秒内快速安全地通过纵向沟渠，保持机器人的倾斜角度小于20°。
