Realizing bipedal locomotion on humanoid robots with point feet is especially challenging due to their highly underactuated nature, high degrees of freedom, and hybrid dynamics resulting from impacts. With the goal of addressing this challenging problem, this paper develops a control framework for realizing dynamic locomotion and implements it on a novel point foot humanoid: ADAM. To this end, we close the loop between Hybrid Zero Dynamics (HZD) and Hybrid linear inverted pendulum (HLIP) based step length regulation. To leverage the full-order hybrid dynamics of the robot, walking gaits are first generated offline by utilizing HZD. These trajectories are stabilized online through the use of a HLIP based regulator. Finally, the planned trajectories are mapped into the full-order system using a task space controller incorporating inverse kinematics. The proposed method is verified through numerical simulations and hardware experiments on the humanoid robot ADAM marking the first humanoid point foot walking. Moreover, we experimentally demonstrate the robustness of the realized walking via the ability to track a desired reference speed, robustness to pushes, and locomotion on uneven terrain.

翻译：在点足人形机器人上实现双足行走极具挑战性，这源于其高度欠驱动的特性、高自由度以及由冲击引起的混杂动力学。为应对这一难题，本文开发了一种用于实现动态行走的控制框架，并将其应用于新型点足人形机器人ADAM。为此，我们在基于混合零动力学（HZD）的步态生成与基于混合线性倒立摆（HLIP）的步长调节之间建立了闭环控制。为充分利用机器人的完整阶次混杂动力学，首先利用HZD离线生成行走步态。这些轨迹通过基于HLIP的调节器在线稳定。最后，通过结合逆运动学的任务空间控制器，将规划轨迹映射到完整阶次系统中。所提方法在ADAM人形机器人上通过数值仿真和硬件实验得到验证，标志着首次实现人形机器人的点足行走。此外，我们通过实验展示了所实现行走的鲁棒性，包括跟踪期望参考速度的能力、抗推扰鲁棒性以及在非平坦地形上的运动能力。