大变形柔性连杆并联机构变形协调运动分析与设计方法研究

The large-scale mobility of flexible parallel manipulators' moving platforms is realized by means of overall continuum deformations of their elastic limbs, rather than concentrated deflections at some local positions. Hence, flexible parallel manipulators can overcome the inevitable drawbacks of the traditional compliant mechanisms, including small range mobility, large deflection stress, and easy to fatigue and failure, so that they have broad application prospects in the fields of human-robot collaboration, medical rehabilitation, aerospace engineering, and so on..The modeling and analysis of those flexible parallel manipulators involve two different disciplines, namely the structural elastic mechanics and the rigid body kinematics, which relate to a typical rigid-flexible coupling system suffering from large deflection problems. As a consequence, there is a lack of effective methodologies to systematically analyze their elasto-static behavior, which severely impedes the research, development and application of such a kind of novel parallel manipulators..Aiming at solving the typical rigid-flexible coupling problems raising in the kineto-static analysis of the flexible parallel manipulator, this proposal is to establish a unified modeling approach which is suitable for both calculation of continuum large deflection of the flexible rods and elasto-static analysis of the rigid parallel mechanisms. Thus, a breakthrough can be achieved to conquer the key computational issues for nonlinear large deformations of rigid-flexible coupling systems under complex constraints. The approach established in this proposal will serve as the theoretical fundamental for the elasto-static modeling, analysis and control of those flexible parallel manipulators. Furthermore, the achievements of this proposal will not only enrich the modeling, analysis and design methodologies of compliant mechanisms, but also promote the application of the flexible parallel manipulators in human-robot collaboration.

大变形柔性连杆并联机构是利用弹性杆件的整体连续变形和多个杆件的变形协调来实现末端大范围运动的一类新型机构。与传统柔顺机构依靠铰链局部集中变形来实现运动的方式不同，大变形柔性连杆并联机构可以采用刚体铰链，主要依靠连杆的连续大范围变形生成末端大范围可控运动，可以克服传统柔顺机构运动范围小、变形应力大和易疲劳失效等缺点，同时本身结构轻巧、具备顺应特性，在人机协作操作等领域具有广阔应用前景。现有弹性力学无法完全解决多根空间柔性杆件在耦合约束下协调变形的解析计算问题，因此这类新机构的运动分析尚无方法；如何将末端运动向耦合约束的每个支链分解，更缺乏构型设计的步骤和方法。因此这类机构运动分析与构型设计是一个全新的问题，本项目拟将连杆大变形进行结构柔度矩阵分解，通过离散化将运动分析和构型设计问题转化为超静定结构和欠驱动机构等效问题求解，建立大变形柔性连杆并联机构变形协调运动分析与构型设计的新理论和新方法。

大变形柔性连杆并联机构是利用弹性杆件的整体连续变形和多个支链变形协调来实现末端大范围运动的一类新型机构。与传统柔顺机构依靠铰链局部集中变形来实现运动的方式不同，大变形柔性连杆并联机构利用连杆的连续大范围变形生成末端大范围可控运动，可克服传统柔顺机构运动范围小、变形应力大和易疲劳失效等缺点，同时本身结构轻巧、具备顺应特性，在仿生机器人和人机协同操作等领域具有广阔应用前景。.柔性连杆并联机构各支链的弹性杆件属于大挠度小应变空间梁结构，其非线性连续变形的准确建模一直都是弹性力学难点之一。本项目提出了一种基于结构柔度矩阵主轴分解的大变形柔性杆件的弹性运动静力一般建模方法。将弹性杆件的大挠度非线性连续变形问题转化为超冗余欠驱动柔性铰链机构的运动静力分析。不仅为柔性连杆并联机构弹性运动分析的统一建模提供了模型基础，也便于利用机器人机构学的成熟方法建立其大挠度非线性变形的解析表征模型。.基于运动静力分析中解析梯度表征的完整刚度映射，建立了大变形柔性连杆并联机构的力觉自感知与结构变刚度模型，提出了相应的柔顺交互控制方法；在理论研究的同时，搭建了适用于各类大变形柔性连杆并联机构的通用实验平台系统，集成了“运动静力仿真分析、伺服电机驱动控制、操作位形视觉测量、力觉感知实时反馈”等多个功能模块，并开展了平面、空间等多种柔性连杆并联机构的验证性实验，为后续各类实验工作开展提供了支撑。.将所提出的柔性连杆并联机构向仿生机器人领域进行拓展研究。利用弹性杆件自身良好的顺应特性和储能单元，分别以“基于仿生鳍条效应的自适应柔性夹钳”和“柔性连杆鱼尾高速摆动机构”作为对象，运用前期理论研究成果开展了抓取性能预测与摆动特性分析等方面工作，验证了本项目理论方法在大变形柔性连杆仿生机构分析中的有效性，为本项目研究成果的拓展应用提供了新的思路和方向。.