基于改进人工势场的苹果采摘机器人机械手避障方法

Obstacle Avoidance Method of Apple Harvesting Robot Manipulator

摘要:

针对非结构化环境下的采摘机器人机械手实时避障问题，提出一种改进人工势场法的避障路径规划方法。根据自行研制的5自由度苹果采摘机器人机械手具体结构和障碍物特征，进行机械手运动学分析和障碍物建模；在保留传统人工势场法易于实现、结构简单等优点的基础上，针对其存在的局部极小点、陷进区等问题，结合果树生长环境中障碍物的特点，通过引入虚拟目标点使搜索过程跳出局部最优的极小点，从而实现机械手避开障碍物到达目标的灵活避障；将该方法应用于机械手末端位置、障碍物位置和目标位置已知条件下的采摘机器人机械手实时避障任务中，仿真和实验研究结果表明此方法简单，实时性好，能够有效地避开障碍物，成功到达目标位置，适合自然生长状态下苹果的自动采摘。

Abstract:

For the problem of real-time path optimization for picking robot manipulator, an improved artificial potential field method was presented for apple picking robot manipulator to avoid obstacle under unstructured environment. According to the concrete structural characteristics of 5-DOF apple picking robot manipulator and obstacle, the manipulator model and obstacle model were analyzed. On the basis of retaining the merits of the traditional artificial potential field method which had simple structure and easy implement, for some of the shortcomings of its existence, such as local minimum points, the stuck district, combined with the characteristics of obstacles in the apple growing environment, a virtual target point was introduced to help the search process escape local optimal minimum point and obtain an optimization smooth motion curve. This method was applied in the obstacle avoidance path planning experiment for the apple picking robot manipulator, which included end-effector, obstacle and targets position. The experimental result showed that the proposed method was simple and enabled to overcome the shortcoming of traditional artificial potential field method.