果蔬侧立采摘柔性手爪设计与变形特性研究

为了实现果蔬的机械化稳定采摘,设计5种非对称柔性手爪结构方案,并对其进行优选;并针对不同负载下柔性手爪侧立抓握时的三维变形特点,提出包括最小工作压力、手指末端垂直位移、手指变形角在内的3个评价指标。通过单指变形特性试验和多指手爪侧立抓握变形特性试验,分析不同状态下的手爪变形规律。研究表明,手指间呈一定角度布置的手爪方案在负载较大时最小工作压力、各项形变指标变化幅度均较小。总体上,手指末端垂直位移对负载的变化更加敏感;工作压力增加有利于手指末端位姿的稳定。采用仿人手4指的手爪方案5综合性能最优,为柔性手爪结构优化以及其形态的精确控制提供了参考依据。

Design and Investigation on the Deformation Characteristics of Soft Robot Hands for Lateral Grasping of Fruit and Vegetables

Five asymmetrical soft robot hands are designed for the stable picking of fruit and vegetables, and optimized. The evaluation indicators were proposed for the analysis of the three dimensional(3D) deformation of fingers in lateral grasping with multi fingered soft hands at different load masses. The indicators included the minimum working pressure, the distortion angle of finger and the vertical displacement of finger. Through the test of the deformation of a single finger with no load at different working pressures and the test for the five multi fingered robot hands in different loads and at different working pressures, the change of deformation of fingers in different working conditions were derived. The results indicate that the robot hands with asymmetrically placed fingers show less increase in the minimum working pressure and deformation when higher load is imposed. For the conditions involved, the vertical movement at end of fingers are more sensitive to changes of loads, and higher working pressure is beneficial for the stable gesture of soft robot hands. Generally, the performance of the four fingered humanoid hand is the best by comparison. These findings will provide a reference for the design optimization and precise control of soft grippers.