Wheel-Legged Balancing Robot

At a Glance

Jumping up one step. Extend, fly, retract, land: the jump state machine driven by the estimated normal force.

Down stairs. Driving down a flight of outdoor stairs step by step; the estimated normal force switches the state machine at each drop.

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Up one step. Driving up a single step with PID leg-height control.

Down one step. Dropping off a curb and landing balanced.

Gravel. Driving over loose gravel. The velocity estimator tolerates wheel slip, so skidding wheels do not affect the balance control.

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Grass. Driving down a grassy slope with uneven, soft ground, body roll held level by PID.

Snow. Fresh snow on a parking lot: smooth turns on a low-friction surface.

Down stairs, failed. The same stairs on another attempt: the robot skips a step, drops two at once, and tips over.

Tripping over an obstacle. A failed attempt at driving down a single step.

Thanks to the teams who open-sourced their work:

basic_framework from Hunan University’s YueLu team, the base of the embedded code.
The balance infantry control system open-sourced by Shanghai Jiao Tong University’s Jiaolong team, the reference for the wheel-legged model and controller.
The wheel-legged balance infantry structure open-sourced by the Hong Kong University of Science and Technology’s ENTERPRIZE team, the reference for the mechanical design.

Thanks also to the members of RoboGrinder at Virginia Tech for their work on this robot.