Design and test of a rigid-flexible cooperative apple-picking robot based on the flexible spiral-drive

摘要

Aiming at the problems of low picking efficiency and fruit damage in existing apple-picking machinery, this paper presents an apple-picking robot equipped with a flexible clamping mechanism and a rigid cutting mechanism, designed specifically for standardized dwarf and densely planted apple orchards. The flexible clamping mechanism primarily consists of three fingers driven by the flexible spiral, each encased in a soft finger sleeve with a finned structure. Analyzing the simplified model of the flexible finger, the factors affecting its bending angle are identified. Based on these factors, the key structural parameters for achieving a single stable clamping of the fruit are determined. Tests on bending angle and output force confirm that the flexible finger meets the stability requirements for clamping apples. To verify the feasibility of trajectory planning and picking strategy, the kinematics equations of the robotic arm are established using the D-H method, the workspace is determined, and the trajectory of the robotic arm is simulated. To verify the performance of the picking robot, the picking test platform and the corresponding control system are built. The picking test results show that the robot achieved the average single-fruit picking time of 4.91 seconds, the picking success rate of 91.11%, and the picking damage rate of 4.89%. This study offers a reference for achieving nondestructive fruit picking using robots.