Despite their inability to take to the skies, birds like ostriches, emus, and chickens use their wings—they’re actually vital to their everyday movements. And unlike existing biomimetic robots that take their cues from high-flying birds, researchers at China’s Shandong University recently built a new, strutting machine inspired by terrestrial avians.
“[H]umans swing their arms to counteract the angular momentum generated by their legs during high-speed movements, such as sprinting,” engineer Xianwu Zeng explained to TechXplore. “Similarly, ostriches and roadrunners use their wings for flight but flap them during rapid running, jumping, or sharp turns, where the wings serve as auxiliary mechanisms.”
With these biological influences in mind, Zeng and colleagues have designed KOU-III. Named in reference to Lie Yukou, a Chinese mythological figure capable of riding the wind, KOU-III is a small, bipedal robot that walks like a chicken, but utilizes a quadrotator system to assist leaping and sprinting. Zeng says that of all ground birds, however, KOU-III is particularly engineered based on the Red-Carpeted Manakin, which employs its wings during ritual courtship jumps.
According to their SSRN preprint paper, Zeng’s team explains that KOU-III’s rotors provide substantial torque for roll and pitch stabilization, as well as vertical lift. This allows the robot to pick up speed without tipping over due to its weight.
“Crucially, during airborne jumps, the robot’s posture can be rapidly adjusted using the rotors,” added Zeng.
In lab testing, KOU-III took 32 seconds to top out at a speed of 0.79 m/s (2.36 ft/s) while walking without its rotors engaged. Past that, however, and the robot’s stability gave out, causing it to topple over. With its rotors on, however, the bot maxed out at 1.1 m/s (3.6 ft/s). When it came to jumping, the rotors allowed KOU-III to jump up 35.2 cm (1.15 ft), which is over its actual height of 32 cm (1.04 ft).
“Building on the successful use of rotors as legged assistance mechanisms, we aim to explore other more efficient and safer auxiliary systems and develop corresponding motion control strategies,” Zeng said. The team believes real-world applications could include exploring narrow, uneven terrains like caves, and even clearing former battlefields of landmines.
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