解耦并联机器人机构混沌现象辨识及其在动力学设计中的应用

The modern machinery is developing to the direction of high speed, precision, heavy load and high reliability, which makes the mechanical dynamics to be the key determining the properties of the mechanical product. The emergence of a series of chaos theory scientific achievements provides mentality for the explain of some phenomenon in mechanism fields. The realization of the motion decoupling of the parallel robot mechanism provides an effective way for the improvement of the dynamic quality and comprehensive performance. In this project, it is taken as the research object for the decoupled parallel robot mechanism with one translation and two rotation degree of freedoms obtainning independent comprehensive, and the mechanism is combined with the chaos theory. The dynamics equations of the mechanism will be set up by the influence coefficient principle, and it will be solved by the Runge-Kutta method. The chaos phenomena in the nonlinear dynamics of the space parallel mechanism is identified by using the numerical analysis method of chaos theory. Then the qualitative and quantitative features of the chaos motion will be determined. The way for the dynamics system of the mechanism from the regular motion to the chaotic state will be analyzed. Therefore the special and excellent dynamics quality of the decoupled parallel robot mechanism will be knew and developed. The optimal design of the mechanism for the minimum driving force and torque of the joints will be carried out based on the reseach results of the chaos. The prototype of the decoupled parallel robot mechanism will be developed, which will lay the foundation for the use or control of the chaos. This project conforms to the requirments of the development of the parallel mechanical equipment, and it is the deepening of the theory research on the dynamics of the robot mechanism and the expandation of the application fields of the chaos theory. So this project has important theoretical guiding meanings and practical application values.

现代机械向高速、精密、重载和高可靠性方向发展，使得机构动力学成为决定其性能的关键。一系列混沌理论科学成果的涌现为机构学中某些现象的解释提供了思路，而并联机器人机构运动解耦的实现则为其动态品质的提高提供了有效途径。本项目以自主综合所得一移动两转动解耦并联机器人机构为研究对象，将机构学与混沌理论相结合，应用机构学中影响系数原理建立机构动力学方程，采用龙格-库塔法予以求解，利用混沌数值分析方法对空间并联机构非线性动力学中的混沌现象予以辨识，确定混沌运动定性与定量特征，分析机构动力系统由规则运动进入混沌状态的途径，认识并开发解耦并联机器人机构动力学的特殊优秀品质,进而应用混沌以关节驱动力/力矩最小为目标开展优化设计，并研制解耦并联机器人样机，为混沌利用或控制奠定基础。本项目顺应并联机械装备研发需求，是对机器人机构动力学理论研究的深化和混沌理论应用领域的拓展，具有较重要的理论指导意义和实践应用价值。

作为非线性领域的重要研究成果，混沌理论具有重大的研究价值和广阔的应用前景。本项目以高速、精密机械装备研发为背景，以运动副含间隙解耦并联机构为研究对象，辨识机构动力学中混沌现象，并探讨其在机构优化设计中的应用。.本项目主要研究内容如下：以RU-RPR和PU-RCRR-CRRR解耦并联机构为研究对象，分析机构运动学，建立转动副间隙的接触力模型；分别考虑两机构不同位置的间隙，建立动力学模型，采用Runge-Kutta法予以数值求解；结合相图、Poincare映射、Lyapunov指数进行混沌辨识，并利用ADAMS软件仿真；增设弹簧以提高机构稳定性，并应用遗传算法开展优化；提出一种新的接触力模型。.本项目主要研究结果为：含间隙运动副对并联机构动平台的位移和速度所造成的影响有限，而动平台的加速度将产生较大波动，通过减小运动副间隙或增大驱动速度可以降低加速度的波动；机构Poincare映射呈现出有规律的自相似图形，最大Lyapunov指数大于0，表明确实存在混沌现象；随着间隙的增大，机构的混沌现象愈加明显，而随着摩擦系数增大，机构又可从混沌状态逐渐转变为周期运动状态；当间隙处于不同位置时，RU-RPR机构的混沌现象强度不同；转动副中间隙的存在使得RU-RPR机构产生混沌和冲击现象，而动力学仿真结果表明混沌现象与冲击现象并无必然联系；驱动速度、摩擦系数的增大能够减弱机构中的混沌现象，但对冲击现象影响有限，而增加弹簧可有效消除机构中的冲击现象；润滑对机构稳定运行影响很大，值得关注；应用遗传算法优化弹簧参数后，机构驱动力矩减小，动力学响应稳定性进一步提高。.本项目研究工作结合并联机器人机构学与混沌理论，有助于深化机构学理论研究并拓展混沌理论应用领域，对具有我国自主知识产权的高端、新型并联机器人装备的研制具有理论指导意义和实践应用价值。