Controller design for bipedal walking on dynamic rigid surfaces (DRSes), which are rigid surfaces moving in the inertial frame (e.g., ships and airplanes), remains largely uninvestigated. This paper introduces a hierarchical control approach that achieves stable underactuated bipedal robot walking on a horizontally oscillating DRS. The highest layer of our approach is a real-time motion planner that generates desired global behaviors (i.e., the center of mass trajectories and footstep locations) by stabilizing a reduced-order robot model. One key novelty of this layer is the derivation of the reduced-order model by analytically extending the angular momentum based linear inverted pendulum (ALIP) model from stationary to horizontally moving surfaces. The other novelty is the development of a discrete-time foot-placement controller that exponentially stabilizes the hybrid, linear, time-varying ALIP model. The middle layer of the proposed approach is a walking pattern generator that translates the desired global behaviors into the robot's full-body reference trajectories for all directly actuated degrees of freedom. The lowest layer is an input-output linearizing controller that exponentially tracks those full-body reference trajectories based on the full-order, hybrid, nonlinear robot dynamics. Simulations of planar underactuated bipedal walking on a swaying DRS confirm that the proposed framework ensures the walking stability under different DRS motions and gait types.
翻译:在动态僵硬表面(即船舶和飞机)上双向行走(DRSes)的操作控制器设计在动态僵硬表面(即质量轨迹和脚步位置的中心)上,在惯性框架(例如船舶和飞机)中移动的僵硬表面,基本上没有调查。本文引入了一种等级控制方法,在水平摇晃的DRS上实现稳定的低动双向机器人行走。我们的方法的最高一层是一个实时运动规划器,它通过稳定一个降序机器人模型(即质量轨迹和脚步站位置的中心)来产生理想的全球行为。这一层的一个关键新颖之处是,通过分析将降序模型的减序模型的衍生出,通过扩展以线性倒转的双向曲(ALIP)模型为基础的角动力,从静止方向向水平移动。另一个创新是开发一个离式的时空脚定位控制器,以指数稳定混合、线和时间对流的ALIP模式。拟议方法的中层是将理想的全球行为模式转换成机器人的完整行行走动参考轨动模型,这是所有行进的行进轨道的行进图,这是所有行进的行进轨道的行进图。