Bipedal Robot

A robot that moves on two legs, the most typical lower-body form for a humanoid.

A bipedal robot moves on two legs, and can be either a full humanoid or just a pair of legs, as with Agility's Cassie. Two legs give a small support base, and walking often passes through phases with only one foot on the ground, making the robot inherently unstable and requiring continuous balance control. Traditional methods plan gaits around the zero moment point, a reference point that predicts whether the foot will tip over, and an inverted pendulum model; Honda's ASIMO is the classic example. In recent years the mainstream approach has shifted to training walking policies with reinforcement learning in simulation, then transferring them to the real robot. The benefit is that a biped can climb stairs, step over obstacles, and enter environments built for humans, at the cost of higher energy use, cost, and fall risk than a wheeled base. Unitree's G1, Agility's Digit, and Booster's T1 are all bipedal robots.

ExampleHonda's ASIMO planned its gait around the zero moment point; Unitree's G1, by contrast, walks using a policy trained with reinforcement learning in simulation.

Also called

Biped, Two-legged Robot

Related

Bipedal Locomotion · Humanoid Robot · Legged Robot · Zero Moment Point · Inverted Pendulum Model (IPM) · Agility Robotics Cassie

Sources

Humanoid robot - Wikipedia
Zero moment point - Wikipedia