Abstract: The click beetle can jump up with a hinge when it is on the dorsal side. This jumping mechanism is simple and suitable as an inspiration for designing a simple, small, and reliable hopping robot. We report a single-legged robot inspired by the jumping mechanism of click beetles. It is 85 mm high, 60 mm long, and 41 mm wide, and weighs about 49 g. The robot has good hopping performance that the hopping height is about 4 times – 4.3 times of its body height. It is capable for rescue missions that require to enter enclosed spaces through cracks and narrow channels. In addition, hopping dynamics of the robot is important to understand its jumping mechanism and improve the robot’s hopping performance. But existing dynamic study does not complete the analysis including all stages in the hopping which are pre-hopping, take-off, and air-flying. We propose the decomposition method to study dynamics of the three stages separately, and synthesize them with related parameters. The dynamic synthesis of multi-motion states in a hopping cycle of the single-legged hopping robot is implemented. The hopping performance and dynamic synthesis theory of the robot are verified by simulations and experiments. Our study helps lay the foundation for design and hopping control of simple hopping robot systems.

Key words: single-legged hopping robots, hopping cycle, dynamics synthesis, multi-motion states, jumping mechanism, imitation of click beetles