Biomimetics (Nov 2024)

Bipedal Stepping Controller Design Considering Model Uncertainty: A Data-Driven Perspective

  • Chao Song,
  • Xizhe Zang,
  • Boyang Chen,
  • Shuai Heng,
  • Changle Li,
  • Yanhe Zhu,
  • Jie Zhao

DOI
https://doi.org/10.3390/biomimetics9110681
Journal volume & issue
Vol. 9, no. 11
p. 681

Abstract

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This article introduces a novel perspective on designing a stepping controller for bipedal robots. Typically, designing a state-feedback controller to stabilize a bipedal robot to a periodic orbit of step-to-step (S2S) dynamics based on a reduced-order model (ROM) can achieve stable walking. However, the model discrepancies between the ROM and the full-order dynamic system are often ignored. We introduce the latest results from behavioral systems theory by directly constructing a robust stepping controller using input-state data collected during flat-ground walking with a nominal controller in the simulation. The model uncertainty discrepancies are equivalently represented as bounded noise and over-approximated by bounded energy ellipsoids. We conducted extensive walking experiments in a simulation on a 22-degrees-of-freedom small humanoid robot, verifying that it demonstrates superior robustness in handling uncertain loads, various sloped terrains, and push recovery compared to the nominal S2S controller.

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