XPENG Robotics’ new bionic humanoid, Iron, is getting uncomfortably close to the real thing, ditching simple rotational joints for a flexible, human-like spine. The robot is built in layers, from a compact skeleton to “muscle-like” lattice structures and a soft outer skin that feels almost human. This biomimetic design allows it to shrug, hug, and walk with a fluid grace that most of its metallic brethren can only dream of, all orchestrated by custom-built reinforcement learning algorithms.