In this paper, we present a Hybrid-Linear Inverted Pendulum (H-LIP) based approach for synthesizing and stabilizing 3D underactuated bipedal walking. The H-LIP model is proposed to capture the essential components of the underactuated part and actuated part of the robotic walking. The walking gait of the robot is then synthesized based on the H-LIP. We comprehensively characterize the periodic orbits of the H-LIP and provably derive their stepping stabilization. The step-to-step (S2S) dynamics of the H-LIP is then utilized to approximate the S2S dynamics of the horizontal state of the center of mass (COM) of the robotic walking, which results in a H-LIP based stepping controller to provide desired step sizes to stabilize the robotic walking. By realizing the desired step sizes, the robot achieves dynamic and stable walking. The approach is evaluated in both simulation and experiment on the 3D underactuated bipedal robot Cassie, which demonstrate dynamic walking behaviors with both versatility and robustness.

翻译：在本文中, 我们展示了基于混合- 利那尔倒转 Pentulum (H- LIP) 的方法, 用于合成和稳定 3D 低活性双向行走。 H- LIP 模型建议捕捉机器人行走中未活化部分和活化部分的基本组成部分。 然后根据 H- LIP 合成机器人的行走步迹。 我们全面描述 H- LIP 的周期轨道, 并可以辨别其步态稳定性 。 然后, H- LIP 的步至步动态( S2S) 用于接近机器人行走中质量中心水平状态的S2S 动态, 从而形成基于 H- LIP 的步控控制器, 以提供所需的步级大小稳定机器人行走。 通过实现理想的步长大小, 机器人可以实现动态和稳定的行走。 在模拟和实验中, 对3D 低活性双活性机器人凯 进行了评估, 这表明具有多性和稳健性的动态行走行为 。