A bionic adaptive end-effector with rope-driven fingers for pear fruit harvesting

More and more fruit harvesting robots have been used in fresh fruit harvesting. Because many fruits are vulnerable, achieving damage-free picking is a challenge for most harvesting robots. Controlling the grasping force of the end-effector is the key to achieving damage-free picking. In this paper, a rope-driven adaptive end-effector for damage-free pear-fruit picking is developed with reference to the human hand, including the human grasping method and the robotics model. A self-developed grasping force system is fitted to the inside of the fingers for real-time control of the end-effector grasping force. A self-developed posture system is installed at the finger knuckles to ensure that the posture of the fingers is in a safe working state. The number of fingers of the end-effector is three, with each finger consisting of two knuckles. Each knuckle is driven by a servo through a rope. Finally, the experiments show that the end-effector grasps stably. And it could adapt to different sizes and shapes of pear fruits. The average grasping time is 0.605 s. The grasping success rate of all fruits is 100 %, and the grasping damage rate is 0 %. This end-effector effectively solves the problem of other end-effectors failing to grasp or causing damage to the fruits. The development of the end-effector positively affects picking operations in agriculture.