提采式名优茶选择性采摘机构设计与试验

Design and Experiment of Selective Picking Mechanism for Premium Tea with Lifting-picking

摘要:

目前名优茶主要通过人工采摘，名优茶的机械化采摘存在茶茎剪切断口发红影响品质、末端执行器尺寸较大影响精准采摘的问题。为此设计了一种模拟人手指夹紧茶茎并提拉的末端执行器，以所测茶叶几何参数、生物力学参数为约束，设计采摘机构、收集机构各杆件尺寸参数；通过Matlab软件和Solidworks软件运动学仿真，验证收集机构各杆件的尺寸参数。确定采摘成功率的影响因素夹具厚度、采摘高度和夹指张角的参数范围，采用Box-Behnken响应面分析方法，以采摘成功率为响应值建立二次回归模型，研究各因素对采摘成功率的交互影响。各因素对采摘成功率的影响显著性主次排序为：夹指张角、夹具厚度、采摘高度；以采摘成功率为优化目标优化各因素，将优化后的各参数最优组合近似处理为：夹具厚度6mm、夹指张角59°、采摘高度3mm。以优化后的参数进行田间试验，结果表明末端执行器采摘成功率为91.67%，试验值与预测值的误差小于5%，影响因素优化结果可靠，表明所设计采摘末端执行器可以达到茶叶高效采摘的要求。

Abstract:

Currently premium teas are primarily harvested manually, as mechanical picking faces challenges such as the reddening of tea stem cut surfaces, which affects quality, and the large size of end effectors, impacting precision in picking. An end effector that simulated the action of human fingers in gripping and lifting tea stems was designed. The design of the picking mechanism and collection mechanism components was constrained by the geometric parameters and biomechanical properties of tea leaves, which were measured. Kinematic simulations using Matlab and Solidworks software were conducted to verify the dimensional parameters of the mechanism components. The key factors influencing the picking success rate—gripper thickness, picking height, and gripper opening angle—were identified, and their parameter ranges were determined. The Box-Behnken response surface analysis method was used to establish a quadratic regression model, with the picking success rate as the response value, to explore the interactive effects of these factors on picking success. The significance of each factor’s impact on the picking success rate was ranked as follows: gripper opening angle, gripper thickness, and picking height. By optimizing these factors with the picking success rate as the objective, the optimization results were obtained as follows: gripper thickness was 6mm, gripper opening angle was 59°, and picking height was 3mm. Field experimental tests using the optimized parameters indicated a picking success rate of 91.67%, with the error between the experimental and predicted values being less than 5%, thereby confirming the reliability of the optimization results, indicating that the designed picking end-effector can meet the requirements for efficient tea picking.