Analysis and realization of a self-adaptive grasper grasping for non-destructive picking of fruits and vegetables

Abstract

Using robotic graspers to harvest fruits and vegetables is a significant advancement in smart agriculture. However, the inherent fragility and varied shapes of many fruits and vegetables pose substantial challenges in achieving adaptive, non-destructive grasping and harvesting with robotic graspers. Grasping motion control and force uniformity control for different objects are essential for achieving non-destructive grasping and harvesting. Firstly, the working principle of the grasper is presented, along with the design of the joint self-locking and unlocking mechanism. Secondly, the grasping contact force during the movement of the grasper knuckle unit is analyzed. Then, a method is proposed to control the stopping of grasper movement through a binary code feedback signal, significantly reducing both the complexity of controlling the grasper and the potential for damage to the object. Building upon this foundation, a novel method for non-destructive grasping motion control is introduced. Finally, the grasping motion control system is developed based on the above theory, and experiments on the adaptive grasping of various fruits and vegetables as well as knuckle motion control are conducted. The experiments show that the grasper can adaptively and non-destructively grasp various shapes and types of fruits and vegetables, effectively solving the problem that the end-effector cannot grasp the fruits or cause damage to the fruits. The work in this paper provides a solution for the realization of intelligent fruit picking by robotic grasper.