Development of Light-weight manipulator for Agriculture

本研究的目的是开发一种轻型农业机械手。农业机器人在野外作业时，为了搬运重物和移动方便，要求机器人具有大功率、轻重量的特点。因此，操纵器和末端执行器需要轻。在本研究中，我们开发了机械手和末端执行器的西瓜收获。末端执行器由四个指状件组成，这些指状件未被致动。它张开手指，在西瓜的表面描出痕迹。我们称之为“被动式抓手”。测量了夹持器与西瓜之间的允许位置误差和接触力。其结果是，它被证实，末端执行器可以抓住西瓜与位置误差。该机械手具有平行四边形连杆机构和罗夫瓦尔机构。其工作空间为2.8m，自重为150N，机械手的三个关节由液压执行机构和直流伺服电机驱动。对机械手进行了定位试验。结果表明，该机械手具有足够的精度，可以满足被动式西瓜采摘的要求。

The object of this research is the development of a light-weight manipulator for agriculture. It requires that agricultural robot in the open field is high power and light weight in order to handle heavy matters and move easily. Therefore, the manipulator and the end effector need to be light. In this research we have developed the manipulator and the end effector for harvesting watermelon. The end effector consists of four fingers, which are not actuated. It opens the fingers with tracing on the surface of watermelon. We call it 'passive type gripper'. The permissible position error and the contact force between the gripper and watermelon were measured. As the result, it was confirmed that the end effector can grasp watermelon with the position error. The manipulator has a parallelogrammic linkage and Roverval mechanism. Its working space is 2.8m and the weight capacity is 150N.Three joints of manipulator are driven by hydraulic actuators and DC servo motor. The positioning test of manipulator was done. As the result, It was found that the manipulator had the sufficient accuracy for harvesting watermelon using the passive type gripper.