To prevent mechanical damage during the feeding and conveying process for leafy greens when roots harvesting, it is necessary to redesign the clamping mechanism in consideration of the rheological properties of leafy greens under the mechanical compression. This study takes spinach, a typical representative of leafy greens, as the research object. Firstly, the rheological constitutive equation for leafy greens under clamping is derived using the Burgers viscoelastic model, and the equation coefficient is identified using a spinach creep test. The damage constraints for the feeding process for different feeding widths are constructed with deformation energy based on the rheological constitutive equation. Secondly, a compliant clamping mechanism with variable stiffness properties is proposed, comprising a clamping floating mechanism and a compact cam pendulum mechanism. This mechanism maintains a preconfigured nonlinear force-displacement curve by utilising off-the-shelf torsional spring and cam profile. Furthermore, the mathematical models of interaction between this mechanism and leafy greens are constructed, with which the low-damage and stable clamping as the optimisation objectives are analysed, and the optimal parameters are achieved with particle swarm optimisation algorithm. Finally, an interactive simulation model of the clamping belt with floating roller supported by the compliant clamping mechanism and the Burgers viscoelastic model is built to simulate the feeding process. The dynamic characteristics of the clamping force are analysed for three feeding widths represented by parallel width of spinach. The experimental results show that relative error of the maximum clamping forces between simulation analysis and theoretical computation is less than 10%, and the relative error between test and theoretical computation is less than 13%, indicating the validity of the simulation model and feasibility of the designed compliant clamping.

为防止根部收获时绿叶蔬菜在进料和输送过程中受到机械损伤，考虑到绿叶蔬菜在机械压缩下的流变特性，有必要重新设计夹紧机构。本研究以绿叶蔬菜的典型代表菠菜为研究对象。首先，利用 Burgers 粘弹性模型推导出了夹持下绿叶蔬菜的流变本构方程，并通过菠菜蠕变试验确定了方程系数。基于流变本构方程，用变形能构建不同喂料宽度下喂料过程的损伤约束。其次，提出了一种具有可变刚度特性的柔性夹紧机构，由夹紧浮动机构和紧凑型凸轮摆机构组成。该机构通过利用现成的扭转弹簧和凸轮轮廓来保持预先配置的非线性力-位移曲线。进一步构建了该机制与绿叶蔬菜相互作用的数学模型，以低损伤、稳定夹持为优化目标，通过粒子群优化算法得到最优参数。最后，建立了柔性夹紧机构支撑的带有浮动辊的夹紧带与Burgers粘弹性模型的交互仿真模型来模拟进料过程。分析了以菠菜平行宽度为代表的三种喂料宽度下夹持力的动态特性。