Authors

Abstract

In recent years, apple harvesters have become a research hotspot. Interaction control between the robot end-effector and the fruit is crucial to reduce mechanical damage to the fruit and achieve high picking performance. In this article, the damage degree was also quantified using a damage factor based on the damage plasticity model. A flexible three-finger end-effector was designed based on the Fin-Ray effect, and finite element models were established in ABAQUS to simulate the cortex damage during grasping. The results showed that the maximum von Mises stress was 0.159 MPa for the apple skin, 0.082 MPa for the cortex, and 4.178 N for the contact force, respectively. The result of the verification test showed that the maximum contact force was 4.572 N, and the relative error between the simulation and experimental results was 8.62%. Simulation and verification tests showed that the flexible three-finger end-effector achieved non-destructive grasping of apples.

Abstract in Chinese

近年来，苹果收获机器人成为研究热点，收获过程中末端执行器与果实的交互作用控制对减少果实损伤起到至关重要的作用。本文基于果肉的损伤塑性模型，测算了果肉在拉伸和压缩过程中的损伤因子，量化了损伤程度；基于鳍条效应设计了柔性三指末端执行器，并建立了末端执行器和苹果的有限元模型。仿真结果表明，果皮Mises最大应力为0.159 MPa，果肉最大应力为0.082MPa，接触压力最大为4.178N。验证试验中，最大接触力为4.572 N。最大接触力仿真值与实际最大接触力的误差为8.62%。仿真与验证试验均表明该柔性三指末端执行器可以实现苹果的无损抓取。