Energy Efficiency in Bipedal Walking vs. Wheeled Robots

Legs are a much less energy-efficient way to get around than wheels — a genuine, unavoidable tradeoff.

Wheeled locomotion on flat ground is fundamentally more energy-efficient than bipedal walking, since a wheel maintains continuous, low-friction rolling contact, while walking involves repeatedly lifting and accelerating the entire leg's mass with every single step.

Why the industry builds legs anyway

Legs can navigate stairs, uneven terrain, ladders, and cluttered environments designed for human bodies, in ways wheels fundamentally can't. The efficiency penalty is a deliberate tradeoff for versatility in exactly the kind of unstructured, human-built environments a general-purpose robot needs to operate in.

Where the gap is narrowing

Better actuator efficiency, regenerative braking, and learned locomotion policies that minimize unnecessary motion have all improved bipedal walking efficiency over time, though a fundamental gap versus wheeled locomotion on flat, predictable ground is likely to persist regardless of how much the technology improves.