Abstract:In order to complete the globose fruit picking well, a multi DOF flexible three-finger gripper of which wrist can rotate was designed by using flexible pneumatic multi-directional bending actuator. The flexible finger, which was compounded with the actuator to form a whole, bended to an arc to fit the surface of the globose fruit when supplied the air pressure. Three fingers cooperated with each other to grasp the globose fruit tightly and the wrist was twisted to separate it from the tree. The fabrication process of the “rigid-flexible coupling” actuator was investigated and acquired, and subsequently a physical prototype of flexible gripper was manufactured. The deformation model of the flexible pneumatic actuator was built and the deformation characteristics of the flexible actuator when supplied air pressure were obtained. Then the experiments were carried out to verify the theoretical model. Also, the physical prototype of the flexible gripper was trial-manufactured. The working space, grasp pattern and mechanical properties of grasping were studied and a variety of globose fruit picking experiments were carried out on the picking platform built in the laboratory. The results showed that the flexible gripper can well complete three kinds of grasping patterns, and it was flexible and reliable and had good compliance to suit the globose fruit. In addition, the flexible fingers were safe to the delicate surface of the fruit which reduced the damage of the fruit greatly. The size of globose fruit that the flexible gripper can complete was ranged from 30mm to 130mm, and the maximum mass was 1.28kg when flexible gripper staggered grasp with three flexible fingers. The research laid a foundation for the further application of flexible gripper.