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Dynamic modeling and active vibration control of a planar 3-PRR parallel manipulator with three flexible links.

机译：具有三个柔性连杆的平面3-PRR并联机械手的动态建模和主动振动控制。

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摘要

Given the advantages of parallel manipulators and lightweight manipulators, a 3-PRR planar parallel manipulator with three lightweight intermediate links has been developed to provide an alternative high-speed pick-and-place positioning mechanism to serial architecture manipulators in electronic manufacturing, such as X-Y tables or gantry robots. Lightweight members are more likely to exhibit structural defection and vibrate due to the inertial forces from high speed motion, and external forces from actuators. Structural flexibility effects are much more pronounced at high operational speeds and accelerations. Therefore, this thesis presents the dynamics and vibration control of a 3-PRR parallel manipulator with three flexible links.;Secondly, this thesis presents the investigation on dynamic stiffening and buckling of the flexible links of a 3-PRR parallel manipulator by including the effect of ii longitudinal forces on the modal characteristics. Natural frequencies of bending vibration of the intermediate links are derived as the functions of axial force and rigid-body motion of the manipulator. Dynamic stiffening and buckling of intermediate links is investigated and configuration-dependent frequencies are analyzed. Furthermore, using Lagrange multipliers, the fully coupled equations of motions of the flexible parallel manipulator are developed by incorporating the rigid body motions with elastic motions. The mutual dependence of elastic deformations and rigid body motions are investigated from the analysis of the derived equations of motion. Open-loop simulation without joint motion controls and closed-loop simulation with joint motion controls are performed to illustrate the effect of elastic motion on rigid body motions and the coupling effect amongst flexible links. These analyses and results provide valuable insight into the design and control of the parallel manipulator with flexible intermediate links.;Thirdly, an active vibration control strategy is developed for a moving 3-PRR parallel manipulator with flexible links, each of which is equipped with multiple PZT control pairs. The active vibration controllers are designed using the modal strain rate feedback (MSRF). The amplification behavior of high modes is addressed, and the control gain selection strategy for high modes is developed through modifying the IMSC method. The filters are developed for the on-line estimation of modal coordinates and modal velocity. The second compensator is used to cut off the amplified noises and unmodeled dynamics due to the differentiation operation in the developed controller. The modal coupling behavior of intermediate links is examined with the modal analysis of vibrations measured by the PZT sensors. The error estimation of the moving platform is examined using the measurement of PZT sensors.;Finally, an active vibration control experimental system is built to implement the active vibration control of a moving 3-PRR parallel manipulator with three flexible links. The smart structures are built through mounting three PZT control pairs to each intermediate flexible link. The active vibration control system is set up using National Instruments LabVIEW Real-Time Module. Active vibration control experiments are conducted for the manipulator moving with high-speed, and experimental results demonstrate that the vibration of each link is significantly reduced.;Firstly, a procedure for the generation of dynamic equations for a 3-PRR parallel manipulator with three flexible intermediate links is presented based on the assumed mode method. The dynamic equations of the parallel manipulator with three flexible intermediate links are developed using pinned-pinned boundary conditions. Experimental modal tests are performed using an impact hammer and an accelerometer to identify the mode shapes, frequencies, and damping ratios of flexible intermediate links. The mode shapes and frequencies, obtained from experimental modal tests, match very well the assumed mode shapes and frequencies obtained based on pinned-pinned boundary conditions, and therefore the dynamic model developed is validated.
机译：鉴于并行机械手和轻型机械手的优势，已经开发了具有三个轻型中间链接的3-PRR平面并行机械手，以为电子制造（例如XY）中的串行体系结构机械手提供一种替代的高速取放定位机制。桌子或龙门机器人。由于高速运动的惯性力和致动器的外力，轻质部件更容易出现结构缺陷和振动。在较高的运行速度和加速度下，结构柔韧性的影响更为明显。因此，本文提出了一种具有三个柔性连杆的3-PRR并联机械臂的动力学和振动控制。其次，本文通过考虑该效应，对3-PRR并联机械臂的柔性连杆的动态刚度和屈曲进行了研究。 ii纵向力对模态特性的影响。中间连杆弯曲振动的固有频率是作为机械手的轴向力和刚体运动的函数得出的。研究了中间连杆的动态加劲和屈曲，并分析了与配置有关的频率。此外，使用拉格朗日乘数，通过将刚体运动与弹性运动结合起来，可以开发出柔性并联机械手的完全耦合运动方程。弹性变形与刚体运动之间的相互依赖性通过对运动方程的分析来研究。进行无关节运动控制的开环仿真和具有关节运动控制的闭环仿真，以说明弹性运动对刚体运动的影响以及柔性连杆之间的耦合作用。这些分析和结果为具有柔性中间连杆的并联机械手的设计和控制提供了宝贵的见识。第三，为具有柔性连杆的移动式3-PRR并联机械手开发了一种主动振动控制策略。 PZT控制对。主动振动控制器是使用模态应变率反馈（MSRF）设计的。解决了高模的放大行为，并通过修改IMSC方法开发了高模的控制增益选择策略。开发了用于在线估计模态坐标和模态速度的滤波器。由于开发的控制器中的微分运算，第二个补偿器用于消除放大的噪声和未建模的动态。通过对PZT传感器测得的振动进行模态分析，检查了中间连杆的模态耦合行为。最后，通过建立主动振动控制实验系统，对具有三个柔性链环的3-PRR并联机械手进行主动振动控制，建立了主动振动控制实验系统。通过将三个PZT控制对安装到每个中间柔性链路上，可以构建智能结构。主动振动控制系统是使用National Instruments LabVIEW Real-Time模块设置的。对高速运动的机械臂进行了主动振动控制实验，实验结果表明，各连杆的振动明显减小。首先，建立了具有三个柔性的3-PRR并联机械臂动力学方程的程序。中间链接是基于假定模式方法给出的。使用固定边界条件开发了具有三个柔性中间连杆的并联机械手的动力学方程。使用冲击锤和加速度计进行实验模态测试，以识别柔性中间链节的模态形状，频率和阻尼比。从实验模态测试获得的模态形状和频率与根据钉扎固定边界条件获得的假定模态形状和频率非常匹配，因此验证了开发的动态模型。

著录项

  • 作者

    Zhang, Xuping.;

  • 作者单位

    University of Toronto (Canada).;

  • 授予单位 University of Toronto (Canada).;
  • 学科 Engineering Mechanical.;Engineering Robotics.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 232 p.
  • 总页数 232
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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