A stability region criterion for flat-footed bipedal walking on deformable granular terrain
A stability region criterion for flat-footed bipedal walking on deformable granular terrain
复制标题
可变形粒状地形上扁平足双足行走的稳定区域准则
DOI：
10.1109/iros.2017.8206323
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
D. Goldman
中科院分区：
文献类型：
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作者：
Xiaobin Xiong;A. Ames;D. Goldman
实现稳定的双足机器人在可变形地形上行走是机器人学和物理学交叉领域的一个开放和具有挑战性的问题。地面变形引入欠驱动;地形动力学的不确定性进一步使动力学建模和控制方法复杂化。这项工作提供了一个稳定的标准，平足双足运动，并允许基于模型的控制方法的功能均匀变形颗粒状地形（如沙子和泥土）。通过表征颗粒材料的静态反作用力，结合颗粒阻力理论（RFT），我们建模并验证了一个静态稳定区域的质心（CoM）投影的颗粒表面上的一个粒子。我们表明，这个稳定区域近似于允许的零力矩点（ZMP）区域行走，使常见的线性倒立摆模型（LIPM）的方法与我们的脚放置策略有效。通过解释的稳定区域的地形的最大反应力矩，我们制定步行作为一个混合动力系统，并利用部分混合零动力学（PHZD）为基础的方法来产生步行步态。最后，我们实验验证了ZMP和PHZD步行步态的平面双足机器人，显示稳定区域的标准允许稳定的动态行走均匀颗粒状地形。
Achieving stable bipedal robotic walking on deformable terrain is an open and challenging problem at the intersection of robotics and physics. Ground deformation introduces underactuation; uncertainty in terrain dynamics further complicates dynamical modeling and control methods. This work provides a stability criterion for flat-footed bipedal locomotion and allows model-based control methods to function on homogeneous deformable granular terrain (e.g. sand and dirt). By characterizing static reaction forces from granular materials, in conjunction with granular resistive force theory (RFT), we model and validate a static stability region for the center of mass (CoM) projection of a biped on a granular surface. We show that this stability region approximates the admissible Zero Moment Point (ZMP) region for walking, rendering common Linear Inverted Pendulum Model (LIPM) methods valid with our foot placement strategy. By interpreting the stability region as the maximum reaction moment of the terrain, we formulate walking as a hybrid dynamical system and utilize the partial hybrid zero dynamics (PHZD) based methodology to generate walking gaits. Finally, we experimentally validate both the ZMP and PHZD walking gaits on a planar bipedal robot, showing that the stability region criterion permits stable dynamic walking on homogeneous granular terrain.