基于支链运动等效的柔性连杆并联机构构型设计

Type Design for Flexible-link Parallel Mechanisms Using Kinematic Equivalence of Limbs

弹性杆/板的连续变形使得柔性连杆并联机构具备灵活运动和被动顺应的能力,但同时也给构型设计带来了很多困难。基于柔度矩阵的主轴分解,建立刚性转动关节和弹性杆/板中离散单元的对应关系,提出一种柔性运动链的设计方法。在此基础上,从刚体2SPR-RPS并联机构的支链出发,得到对应等效柔性运动链的构型方案,并采用以弹性势能最小为目标的优化模型对其最佳等效的存在性进行验证。进一步地,通过对刚性支链的整体替换设计一种柔性类2SPR-RPS并联机构,并采用运动静力分析对其自由度特性和工作空间进行讨论。运动学研究的结果表明文中柔性连杆并联机构设计方法是正确且合理的。

Continuous deformation of elastic rods/sheets gives flexible-link parallel mechanisms the capability of dexterous motion and passive compliance,but simultaneously produces dificulties toward their type design.Based on the principal axis decomposition of a compliance matrix,the relation between the rotating joints in a rigid chain and the joint twists in discretized elements of an elastic rod/sheet is established,and hence a kinematic equivalence approach is proposed for the design of flexible chains.Then,with reference to the rigid limbs of the 2SPR-RPS parallel mechanism,the types of the corresponding flexible chains are invented and subsequently identified via a validating model with minimum elastic potential energy as its objective.Finally,limb replacement is applied to generate the type of a flexible 2SPR-RPS parallel mechanism,which is then researched from the aspect of mobility and workspace.The kinematic results demonstrate that the design approach in this paper is correct and feasible.