Actuation and Motion Control of Flexible Robots: Small Deformation Problem
Actuation and Motion Control of Flexible Robots: Small Deformation Problem
复制标题
柔性机器人的驱动和运动控制：小变形问题
DOI：
10.1115/1.4051438
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Bai, Zhengfeng
中科院分区：
文献类型：
--
作者：
Shabana, Ahmed A.;Bai, Zhengfeng
本文介绍了一种新的计算方法的关节/变形驱动和运动控制的机器人操作器与柔性部件。振动，由于相对刚性的机器人组件，不能忽略的小变形，在这项研究中使用有限元（FE）浮动参考系（FFR）制定采用两组耦合的坐标：参考和弹性坐标。基于FFR公式的逆动力学导致与变形自由度相关联的驱动力。由于连杆的柔性，可以考虑两种方法来确定实现期望的运动轨迹所需的致动力。这两种方法是部分约束逆动力学（PCID）和完全约束逆动力学（FCID）。FCID方法，这将被认为是在未来的调查，并允许运动和形状控制，可以用来实现所需的运动轨迹和抑制不希望的振荡。在这项研究中引入的新的小变形PCID方法，另一方面，允许实现所需的运动轨迹，系统地确定与机器人关节和弹性自由度的驱动力和力矩，并避免恶化的振动特性之间的差异测量的逆和正向动力学解决方案。提出了一种用于确定与变形自由度相关联的致动力的方法，并使用压电致动器进行了举例说明。的PCID解决方案是用来定义一组新的代数方程，可以解决的压电驱动电压需要保持其逆动力学范围内的前向动力学振荡。一个平面的两连杆柔性机器人操作器，演示关节/变形驱动方法的实施。结果表明，如果不考虑变形驱动，机器人精度会恶化。
This paper introduces a new computational approach for the articulated joint/deformation actuation and motion control of robot manipulators with flexible components. Oscillations due to small deformations of relatively stiff robot components which cannot be ignored, are modeled in this study using the finite element (FE) floating frame of reference (FFR) formulation which employs two coupled sets of coordinates: the reference and elastic coordinates. The inverse dynamics, based on the FFR formulation, leads to driving forces associated with the deformation degrees of freedom. Because of the link flexibility, two approaches can be considered to determine the actuation forces required to achieve the desired motion trajectories. These two approaches are the partially constrained inverse dynamics (PCID) and the fully constrained inverse dynamics (FCID). The FCID approach, which will be considered in future investigations and allows for motion and shape control, can be used to achieve the desired motion trajectories and suppress undesirable oscillations. The new small-deformation PCID approach introduced in this study, on the other hand, allows for achieving the desired motion trajectories, determining systematically the actuation forces and moments associated with the robot joint and elastic degrees of freedom, and avoiding deteriorations in the vibration characteristics as measured by the differences between the inverse- and forward-dynamics solutions. A procedure for determining the actuation forces associated with the deformation degrees of freedom is proposed and is exemplified using piezoelectric actuators. The PCID solution is used to define a new set of algebraic equations that can be solved for the piezoelectric actuation voltages required to maintain the forward-dynamics oscillations within their inverse-dynamics limits. A planar two-link flexible-robot manipulator is presented to demonstrate the implementation of the joint/deformation actuation approach. The results obtained show deterioration in the robot precision if the deformation actuation is not considered.