中文摘要：

针对具备持续动力输入和果实约束变形两大特殊性的果实夹持碰撞问题,以果实黏弹性Burger＇s模型为基础,提出并建立了夹持器恒速模式与负载能力限定下的果实夹持碰撞三阶段复合模型。试验证实初始夹持速度19.2 mm/s下,该模型的峰值碰撞力预测误差仅为1.12%。基于该三阶段复合模型对果实夹持碰撞规律的分析发现,以恒速模式实施果实夹持时,初始夹持速度6 mm/s完成绿熟期、变色期、红熟初期与红熟中期番茄果实夹持所需时间分别仅为0.62 s、1.06 s、1.19 s和1.24 s,而超过10 mm/s后继续加大初始夹持速度对提高作业效率的作用有限。峰值碰撞力和果实变形分别与夹持速度呈线性和近似线性关系,随着初始夹持速度的提高果实破裂损伤的概率大大增加,当初始夹持速度低于20 mm/s时番茄果实损伤概率反而呈现绿熟期最高而红熟初期最低的现象。该模型为揭示夹持碰撞的特殊规律和实现果实快速柔顺夹持作业提供了借鉴和依据。

英文摘要：

This paper focused on the special collision phenomenon of fruit gripping with its own characteristics of continuous energy input and restrained deformation.The gripping collision process was divided into three stages： constant-speed loading,collision decelerating and stress relaxation,and a three-stage gripping collision model was put forward under the conditions of constant static loading capacity and constant speed control mode,which was based on the stage dynamic characteristic of gripping collision process and viscoelastic Burger＇s model of fruits.It was proved by test that the prediction of the peak collision force was feasible,and the predicton error under initial gripping speed of 19.2 mm/s was 1.12%.By calculating with this model,it was found that time needed to grip fruit in different ripe period under initial speed of 6 mm/s was 0.62 ~ 1.24 s,and further raising the initial speed might have very limited effectiveness to improve the gripping efficiency.The peak collision force and fruit deformation were proportional and approximately proportional to initial gripping speed,respectively.Probability of skin rupture increased greatly with initial gripping speed.When initial gripping speed was under 20 mm/s,probability of skin rupture of green ripening stage and early red ripening stage were the greatest and the least,respectively.This three-stage gripping collision model may provide helpful reference to discover the special law of gripping collision and to achieve high-speed safe gripping of fruits.