蛇形机器人在障碍物环境中的运动研究

摘要

蛇形机器人要走向实际应用，必须着力解决的首要问题是如何在复杂环境中运动以及实现适应环境的避障基础理论问题。本文致力于研究蛇形机器人在复杂环境中的避障运动。

目前蛇形机器人普遍采用模块化结构，以便于设计安装和节约成本。蜿蜒运动是蛇形机器人通过各个模块间规律性的振荡推动整个蛇体运动的一种运动步态，是蛇形机器人运动效率较高的一种运动方式[1]。这种运动方式不同于普通的行走机器人，维护模块之间的规律性振荡产生蜿蜒运动使运动控制变得复杂，更增加了复杂环境中路径规划的难度。本文在蜿蜒运动理论基础上，基于几何法、人工势能法和改进后的人工势能法对蛇机器人在障碍物环境下的运动进行规划。利用几何方法探讨了通过规划蛇头与规划整个蛇体对蛇形机器人运动路径的影响，得到更有利于运动稳定性的规划方法，为人工势能法奠定基础。应用人工势能法中将障碍物赋予高势能产生排斥力，将目标赋予低势能产生吸引力，使蛇形机器人在排斥力与吸引力的作用下避开障碍物到达目标。在人工势能法中，蛇形机器人在纵向方向偏移障碍物的距离过大，这不仅浪费了能量，而且增加了运动时间。综合蛇形机器人前进方向与障碍物势能的关系，对人工势能法进行改进。将障碍物产生的排斥力组成的等势面改成椭圆形，不仅缩短了运动路径更提高蛇形机器人的运动稳定性。分析外力对蛇形机器人的运动方向及运动稳定性的影响，建立了避障过程中的力学理论。最后，通过3D 动力学模型模拟真实机器人在障碍物环境中的避障运动，验证了避障方法的可行性。

本文的研究对蛇形机器人在障碍物环境中的路径规划具有推动作用，为蛇形机器人的应用奠定理论基础。

关键词：蛇形机器人；障碍物；人工势能；运动；动力学

Abstract

If the applications of snake-like robot were true, the most important things to be solve that the snake-like robot how to move in rugged environment and how to avoid the obstacles.This thesis focuses on how to make the moving snake-robot without collision in environmentwith obstacles.

Winding movement caused by the regular oscillation interaction between the adjacent joints of snake-like robot is very efficient, which is different from the general walking robots movement. Snake robot becomes difficult in complicated environment to keep regularoscillation to produce the winding movement. This paper uses winding movement to plan the snake-like robot’s movement in the environment with obstacle s based on geometry, artificial potential method and the improved artificial potential method. Snakehead planning method or the whole body planning of the snake-like robot method is investigated in geometry method. Results of Two types of simulation are analyzed to choose which way is better for snake-like robot locomotion. The obstacles with repulsive force are given high potential energy. And the target with attractive force is given low potential energy in artificial potential method. The snake-like robot reaches the target without collision with obstacles in environment by these force. However, the distance is too longer in the longitudinal direction from the obstacle, which wastes much energy and computing time. Therefore, the artificial potential method is improved for getting better path. When equipotential surfaces which composed of repulsive force are changed round into oval, the path would not only be shorted but also the stability of the movement would be better. The force changed the original snake-like robot force in the artificial potential method. Dynamics analysis of the snake-like robot would be analyzed by considering the moving direction and motion stability when the external force exerting on the snake-like robot. Finally, the 3D dynamic simulation verifies the path planning of snake-like robot in the environment with obstacles.

These studies give impetus to the snake-like robot path planning. These obstacle avoidance methods have some reference meanings to the application of snake robot. .

Key words：snake-like robot; obstacle; artificial potential; motion; dynamics