EXTERNAL SENSING SYSTEM FOR AGRICULTURAL ROBOT

开发并测试了一种用于人类合作农业机器人的外部传感系统。传感系统由激光扫描仪和红外传感器组成。激光扫描仪安装在上下移动距离为300毫米的升降机上，以捕获三维距离数据。红外传感器被用来探测人的存在。从实验结果来看，通过上下移动激光扫描仪，不仅可以探测到物体的距离，还可以探测到物体的形状。基于激光扫描仪和红外传感器获得的信息，检测人体的运动，包括位置、速度和方向。研究了一种人体识别算法。从结果来看，即使人体之间有一定距离交叉重叠，也能实现识别。此外，还进行了机械手避障控制实验，验证了传感系统的有效性。首先，利用激光扫描仪测量机器人周围物体的距离和形状，确定机器人的避碰运动；其次，机械手在躲避物体的同时移动。当红外传感器检测到机器人周围有人体时，计算危险程度，然后控制机械手尖端的速度。从实验结果来看，机械手避开其操作区域内的障碍物，并与危险程度值成比例地改变其速度。

An external sensing system for human cooperative agricultural robots was developed and tested. The sensing system consisted of a laser scanner and infrared sensors. The laser scanner was mounted on a lift moved up and down at a distance of 300 mm to capture a three-dimensional distance data. The infrared sensors were used to detect the existence of human. From the experimental results, not only the distance to an object but also the shape of the object was detected by moving the laser scanner up and down. The human motions including location, speed and direction were detected based on the information obtained from the laser scanner and the infrared sensors. An algorithm for discriminating human bodies was also investigated. From the result, the discrimination was achieved even if human bodies overlapped each other crosswise when there was some distance between them.Furthermore, manipulator control experiments for obstacle avoidance were carried out to confirm effectiveness of the sensing system. First, the distances and the shapes of objects around a robot were measured by the laser scanner, and an avoidance motion of manipulator was decided. Secondly, the manipulator moved while avoiding the object. The degree of danger was calculated when infrared sensors detected a human body around the robot, then a speed of manipulator tip was controlled. From the experimental results, the manipulator avoided obstacles within its operating area and changed its speed in proportion to the value of degree of danger.