Pushing revisited: Differential flatness, trajectory planning, and stabilization
Pushing revisited: Differential flatness, trajectory planning, and stabilization
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DOI：
10.1177/0278364919872532
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发表时间：
2019-09
期刊：
影响因子：
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通讯作者：
Jiaji Zhou;Yifan Hou;M. T. Mason
中科院分区：
文献类型：
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作者：
Jiaji Zhou;Yifan Hou;M. T. Mason
我们证明了具有粘着接触和椭球近似极限面的准静态推动是微分平坦的。给出了图形和代数推导。一个主要结论是，推杆-滑块系统可以简化为杜宾斯汽车问题，其中粘着接触约束转化为有界曲率。规划就像计算杜宾斯曲线一样简单，并且具有时间最优性的额外优势。为了稳定轨迹，我们设计使用动态反馈线性化的闭环控制或使用两个接触点作为机械反馈形式的开环控制。我们使用不同压力分布、形状和接触材料的物体进行机器人实验，这些物体放置在不同的初始姿势，需要困难的切换动作才能达到目标姿势。经过 60 次实验试验，平均平移误差在 1.67 毫米以内，方向平均误差在 0.5° 以内。我们还展示了使用具有精确转向功能的 RRT 规划器在障碍物中推动的示例。
We prove that quasi-static pushing with a sticking contact and ellipsoid approximation of the limit surface is differential flat. Both graphical and algebraic derivations are given. A major conclusion is that the pusher–slider system is reducible to the Dubins car problem where the sticking contact constraints translate to bounded curvature. Planning is as easy as computing a Dubins curve with the additional benefit of time-optimality. For trajectory stabilization, we design closed-loop control using dynamic feedback linearization or open-loop control using two contact points as a form of mechanical feedback. We conduct robotic experiments using objects with different pressure distributions, shape, and contact materials placed at different initial poses that require difficult switching action maneuvers to the goal pose. The average error is within 1.67 mm in translation and 0.5° in orientation over 60 experimental trials. We also show an example of pushing among obstacles using a RRT planner with exact steering.