H-shaped bionic robot mimics cheetah’s sprint using electric charge

In recent years, roboticists and computer scientists have developed a wide range of systems inspired by nature, particularly by humans and animals. By reproducing animal movements and behaviors, these robots could navigate real-world environments more effectively.

Researchers at Northeastern University in China recently developed a new H-shaped bionic robot that could replicate the movements that cheetahs make while running. This robot, introduced in a paper published in the Journal of Bionic Engineering, is based on piezoelectric materials, a class of materials that generate an electric charge when subjected to mechanical stress.

“The piezoelectric robot realizes linear motion, turning motion, and turning motion with different radii by the voltage differential driving method,” wrote Ying Li, Chaofeng Li and their colleagues in their paper. “A prototype with a weight of 38 g and dimensions of 150 × 80 × 31 mm³ was fabricated.”

The new H-shaped bionic piezoelectric robot (H-BPR) developed by Li, Li and their colleagues has four legs connected by three piezoelectric beams. To emulate the running gait of cheetahs, the robot leverages the bending vibrations of the piezoelectric beams, which move its four legs periodically.

“Firstly, the dynamics and kinematics of the piezoelectric robot were analyzed to obtain the trajectory of a point at the end of the piezoelectric robot leg,” wrote the researchers. “The motion principle of the piezoelectric robot was analyzed, and then the piezoelectric robot’s modal analysis and harmonic response analysis were carried out using finite element analysis software.”

Compared to other robots that move leveraging waves in piezoelectric materials, the new system developed by these researchers has a simpler design and could thus be easier to fabricate. In addition, it can produce a wider range of movements, as its motions and the radius at which it turns can be tuned by adjusting the voltage applied to it.

So far, Li, Li and their colleagues have developed a basic prototype of the robot, which can also carry small loads. In the future, however, its design could also be adapted to integrate miniature sensors or cameras, which could broaden the robot’s capabilities.

The researchers tested the prototype they developed in a series of real-world experiments, which yielded promising results. Overall, the robot was found to mirror the running gait of cheetahs pretty well while also successfully climbing ramps with different inclinations.

“An experimental setup was built to verify the effectiveness and high efficiency of the robot’s motion,” wrote the researchers. “The performance test results show that the piezoelectric robot has a maximum velocity of 66.79 mm/s at an excitation voltage of 320 V and a load capacity of 55 g. In addition, the H-BPR with unequal drive legs has better climbing performance, and the obtained conclusions are informative for selecting leg heights for piezoelectric robots.”

The new robotic system developed by this team of researchers could soon inspire the development of other similar robots based on piezoelectric materials. In the future, the team could further improve their robot to ensure that it can effectively operate at extreme temperatures, in challenging climates, or in the presence of hazardous chemicals, as this would facilitate its deployment in industrial settings or during search and rescue missions.

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