  Wheeled bipedal robots offer the advantages of both wheeled and legged
robots, combining the ability to traverse a wide range of terrains and
environments with high efficiency. However, the conventional approach in
existing wheeled bipedal robots involves motor-driven joints with high-ratio
gearboxes. While this approach provides specific benefits, it also presents
several challenges, including increased mechanical complexity, efficiency
losses, noise, vibrations, and higher maintenance and lubrication requirements.
Addressing the aforementioned concerns, we developed a direct-drive wheeled
bipedal robot called DIABLO, which eliminates the use of gearboxes entirely.
Our robotic system is simplified as a second-order inverted pendulum, and we
have designed an LQR-based balance controller to ensure stability.
Additionally, we implemented comprehensive motion controller, including yaw,
split-angle, height, and roll controllers. Through expriments in simulations
and real-world prototype, we have demonstrated that our platform achieves
satisfactory performance.
