Why Do Humanoid Robots Still Struggle With the Small Stuff? | Quanta Magazine

To have robots which work like humans, I think we have to master physics.... Kim’s actuators got around the problem with controllable “compliance,” or flexible springiness. Over the past decade, they’ve gotten cheaper and more widely accessible. “Reinforcement learning solved a lot of the [bipedal] locomotion problem, but the hardware was the enabler,” Kim said. If reinforcement learning and compliant actuation were gifts to humanoid robotics, multimodal AI put a bow on it.

Cut to now. Humanoids have apparently become so advanced that Tesla is mothballing some electric car models to make way for its Optimus humanoid robot, and start-ups are preselling android butlers with a straight face. Hype aside, I was genuinely curious: Did a paradigm shift happen in the field when I wasn’t looking?

Surely today’s robotic bipedal marvels can ascend a few stairs and open a door without breaking a nonexistent sweat, something they famously struggled with a decade ago. I asked each researcher: Can your flagship robot — Boston Dynamics’ Atlas or Agility’s Digit, two of the most credible and pedigreed humanoids on Earth — handle any set of stairs or doorway?

Roboticists once coordinated each movement with various hand-engineered algorithms, using equations to model the (simplified) physics of the robot. Now they train neural networks to act as “whole-body controllers” by running countless digital simulations of the humanoid.

To have robots which work like humans, I think we have to master physics.... Kim’s actuators got around the problem with controllable “compliance,” or flexible springiness. Over the past decade, they’ve gotten cheaper and more widely accessible. “Reinforcement learning solved a lot of the [bipedal] locomotion problem, but the hardware was the enabler,” Kim said. If reinforcement learning and compliant actuation were gifts to humanoid robotics, multimodal AI put a bow on it.