Output Mode Switching for Parallel Five-bar Manipulators Using a Graph-based Path Planner
Output Mode Switching for Parallel Five-bar Manipulators Using a Graph-based Path Planner
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DOI：
10.1109/icra48891.2023.10160891
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发表时间：
2022-09
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影响因子：
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通讯作者：
Parker B. Edwards;A. Baskar;Caroline Hills;Mark M. Plecnik;J. Hauenstein
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作者：
Parker B. Edwards;A. Baskar;Caroline Hills;Mark M. Plecnik;J. Hauenstein
并联机器人位形空间比串联机器人位形空间具有更强的非线性。从质量上看，它们可以看到拥有额外的褶皱。投影到工程相关的较小空间上，例如输出工作空间或输入致动器空间，这些折叠投射出表现出边界行为的边缘。例如，在一个五杆机构的全局工作空间边界内出现了几个局部工作空间边界，它们只约束机构的某些输出模式。这种边界的存在，表现在输入和输出投影，作为一个来源的混乱时，这些投影专门研究，而不是配置空间本身。特别是，非对称并联机器人的设计已被混淆的奇异投影在其输入和输出空间的存在。在本文中，我们表示的配置空间的半径图，然后加权每个边缘通过解决一个优化问题，使用同伦连续量化传输质量。然后，我们采用了图形路径规划器近似的配置点，避免低传输质量的区域之间的测地线。我们的方法自动生成能够在非相邻输出模式之间转换的路径，该运动涉及密切多个工作空间边界（局部，全局或两者）。我们将我们的技术应用到两个非对称的五杆的例子，演示如何传输特性和其他特性的工作空间可以通过切换输出模式进行选择。
The configuration spaces of parallel manipulators exhibit more nonlinearity than serial manipulators. Qualitatively, they can be seen to possess extra folds. Projection onto smaller spaces of engineering relevance, such as an output workspace or an input actuator space, these folds cast edges that exhibit boundary behavior. For example, inside the global workspace bounds of a five-bar linkage appear several local workspace bounds that only constrain certain output modes of the mechanism. The presence of such boundaries, which manifest in both input and output projections, serve as a source of confusion when these projections are studied exclusively instead of the configuration space itself. Particularly, the design of nonsymmetric parallel manipulators has been confounded by the presence of exotic projections in their input and output spaces. In this paper, we represent the configuration space with a radius graph, then weight each edge by solving an optimization problem using homotopy continuation to quantify transmission quality. We then employ a graph path planner to approximate geodesics between configuration points that avoid regions of low transmission quality. Our methodology automatically generates paths capable of transitioning between non-neighboring output modes, a motion which involves osculating multiple workspace boundaries (local, global, or both). We apply our technique to two nonsymmetric five-bar examples that demonstrate how transmission properties and other characteristics of the workspace can be selected by switching output modes.