柔性机械臂的动力学建模与弹性振动控制研究

发布时间：2018-01-13 11:03

本文关键词：柔性机械臂的动力学建模与弹性振动控制研究　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：柔性机械臂作为刚柔耦合多体动力学系统的典型代表,广泛应用于航空航天、机器人及现代智能制造领域中。对比体积庞大的刚性机械臂,柔性机械臂具有低耗能、操作空间大、载荷自重比高等优点。在实际的操作过程中,柔性机械臂的运动往往由大范围的刚体运动和由柔性体的弹性变形引起的弹性振动组成。这两种不同的运动形式使得柔性机械臂系统是一个非线性的刚柔耦合时变系统。由于弹性振动的存在,使得柔性臂在运动过程中的定位精度下降,甚至降低系统的可靠性。针对柔性臂的振动问题,本文根据当前国内外关于柔性系统动力学建模及弹性振动控制领域里的研究成果,对单连杆柔性机械臂的动力学特性和振动控制问题进行研究。主要研究内容如下:首先,以结构力学和机械振动为基础,建立末端具有集中质量的单连杆柔性机械臂的数学模型,采用假设模态方法描述柔性机械臂弹性变形并进行动力学分析。基于Lagrange方程建立柔性臂的动力学方程并推导出状态空间表达式,分析柔性臂的前六阶模态,为后续的振动控制器设计和实验仿真提供依据。其次,采用反馈控制的形式,根据线性二次型最优控制的基本原理,运用线性二次型最优控制对柔性机械臂进行振动控制。选取不同的加权矩阵,实验结果证实能有效抑制柔性臂末端弹性振动。采用遗传算法搜索最优的加权矩阵,优化后的线性二次型最优控制与优化前相比,能更快的衰减末端振动能量,改善振动抑制效果。最后,采用前馈控制的方式,研究柔性机械臂的弹性抑振问题。分析在不同轨迹规划函数下的角位移及角速度,采用遗传算法优化基于五次多项式函数轨迹规划下的柔性机械臂运动轨迹。利用五次多项式函数插值得到优化后的最优振动控制轨迹曲线。与优化前的运动轨迹相比,优化后的柔性机械臂在最优轨迹控制下能有效衰减末端残余振动能量。研究内容和实验结果不仅对单杆柔性机械臂系统的动力学建模及振动控制有实用价值,而且也为更复杂的柔性系统研究提供了方法和思路。
[Abstract]:As a typical representative of rigid-flexible coupling multi-body dynamics system, flexible manipulator is widely used in aerospace, robot and modern intelligent manufacturing field. Flexible manipulator has the advantages of low energy consumption, large operating space, high load to weight ratio and so on. The motion of flexible manipulator is usually composed of a wide range of rigid body motion and elastic vibration caused by elastic deformation of flexible body. These two different motion forms make the flexible manipulator system a nonlinear rigid-flexible coupling. Variable systems. Due to the existence of elastic vibration. The positioning accuracy of the flexible arm in the process of motion is reduced, and even the reliability of the system is reduced, aiming at the vibration of the flexible arm. This paper is based on the current domestic and foreign research achievements in the field of dynamic modeling and elastic vibration control of flexible systems. The dynamic characteristics and vibration control of single link flexible manipulator are studied. The main contents are as follows: firstly, based on structural mechanics and mechanical vibration. The mathematical model of single link flexible manipulator with concentrated mass at the end is established. The dynamic equations of flexible manipulators are established based on Lagrange equation and the expression of state space is derived. The first six modes of the flexible arm are analyzed to provide the basis for the subsequent vibration controller design and experimental simulation. Secondly, the feedback control is adopted according to the basic principle of linear quadratic optimal control. The linear quadratic optimal control is used to control the vibration of the flexible manipulator. Different weighting matrices are selected. The experimental results show that the elastic vibration at the end of the flexible arm can be suppressed effectively. Genetic algorithm is used to search the optimal weighting matrix. The optimized linear quadratic optimal control can attenuate the vibration energy of the end faster than that before the optimization. Finally, the elastic vibration suppression problem of flexible manipulator is studied by feedforward control. The angular displacement and angular velocity under different trajectory planning functions are analyzed. Genetic algorithm is used to optimize the trajectory of flexible manipulator based on the trajectory planning of quintic function. The optimal trajectory curve of vibration control is obtained by interpolation of quintic function. Compared to. The optimized flexible manipulator can effectively attenuate the residual vibration energy of the end under the optimal trajectory control. The research contents and experimental results are not only of practical value for the dynamic modeling and vibration control of the single rod flexible manipulator system. It also provides methods and ideas for the study of more complex flexible systems.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP241

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