基于浮动坐标系的大变形柔性机器人动力学建模和仿真

In the fields of aerospace, aviation and robotics, the modern robots are now developing towards the high speed, precise and smart operation, the large span structures, and the lightweight materials with distributed flexibility. In these cases the large deformations of structures, the dynamic coupling between the large overall rigidbody motion and the deformations of the robot system have become a general puzzle and a key technique in the above engineering fields. In this project the above outstanding problems will be investigated in details at the levels of theoretical analysis and numerical simulation. The universal and efficient dynamic modeling theory and numerical simulation technique for the flexible-link and flexible-joint robots with large deformations will be studied via using the floating frame of reference formulation. The research work carried out in this project will benefit to the applications in the fields of aerospace, aviation and robotics, and also enrich the dynamics theory of flexible multibody systems. This project will mainly focus on the following topics: ..1. The precise description of the link with complex geometric shape, and its corresponding efficient discretizing method; the investigation into the dynamic modeling and dynamic properties of the one-link flexible arm with complex geometry.. .2. The rigid-flexible coupling dynamic modeling and simulation of the multi-link flexible robots with flexible links and flexible joints, and complex topologies such as tree like structures and closed loops, in which the link can be of complex geomeric shape and its deformation can be large, the flexibility of the joint and its mass will also be included...3. The development of the general purpose software package for the dynamic simulation of the flexible-link and flexible-joint robots.

本项目以航天和机器人工程为背景，针对太空机器人这类具有轻质、大跨度、高效、灵活等特点的复杂机器人在运动过程中出现的构件大变形和强烈的刚柔耦合等动力学过程问题，通过理论建模和数值仿真手段，重点研究高效和通用的基于浮动坐标系的柔性杆柔性铰机器人在大变形下的刚柔耦合动力学建模理论和计算机仿真技术。本课题的研究不仅在机器人和航天领域有重大的应用价值，而且对推动多柔体系统动力学理论的发展具有重要的学术价值。本课题的主要研究内容为：1.复杂几何杆形的单杆柔性机器人的大变形刚柔耦合动力学建模和动力学性态研究，并提出精确描述复杂几何形状、高效的变形体离散方法；2.复杂拓扑构型和几何杆形的多杆柔性机器人考虑铰柔性效应和质量效应，考虑杆大变形效应的刚柔耦合动力学建模理论和仿真技术；3.能实现上述建模理论程式化计算的柔性杆柔性铰机器人动力学仿真软件的研制。

本项目以航天和机器人工程为背景，针对太空机器人这类具有轻质、大跨度、高效、灵活等特点的复杂机器人在运动过程中出现的构件大变形和强烈的刚柔耦合等动力学过程问题，通过理论建模和数值仿真手段，重点研究高效和通用的基于浮动坐标系的柔性杆柔性铰机器人在大变形下的刚柔耦合动力学建模理论和计算机仿真技术。本课题的研究不仅在机器人和航天领域有重大的应用价值，而且对推动柔性多体系统动力学理论的发展具有重要的学术价值。本项目主要研究了如下内容：.1.柔性体离散方法研究. 将计算几何方法中的B样条插值法、Bezier插值法，无网格法中的无网格点插值方法、无网格径向基点插值法和光滑节点插值法等方法引入柔性体的变形场描述或离散，并且通过动力学仿真验证了方法的可行性和优越性。采用径向基点插值法对传统的绝对节点坐标法进行了改进，提高了计算精度。.2.大变形柔性体刚柔耦合动力学建模理论研究. 以单杆柔性机器人为研究对象，研究了大变形刚柔耦合动力学问题，分别提出了浮动坐标系下的高阶耦合模型、曲率纵向变形效应模型和基于节点坐标的浮动坐标系法。对做大范围旋转运动的柔性梁、板的动力学特性进行了研究，分析了“频率转向”和“模态转换”等现象。.3. 多杆柔性杆柔性铰机器人大变形动力学建模和仿真软件研制.4. 柔性机器人的碰撞动力学研究. 提出了将冲量-动量法(离散法)和接触约束法相结合求解碰撞动力学问题的新方法, 即：先以离散法实现运动转换得到协调的碰撞接触约束初始条件，再以接触约束法求解碰撞过程。.5. 高效高精高稳定的数值计算方法研究. 研究了用于求解四种多体系统动力学微分-代数方程组的状态空间法。基于LU分解构造了新型的状态空间法以便对仅含完整约束的问题、仅含线性非完整约束的问题、含有完整-线性非完整混合约束的问题以及含有完整-非线性非完整混合约束的问题这四种含有不同类型约束问题的多体系统动力学微分-代数方程组进行数值求解，所提出的方法高效、高精和高稳定。