Design and fabrication of a bio-inspired frog robot based on electromagnetic catapult

This paper presents an electromagnetic catapult-driven bio-inspired frog robot. Its core innovation is a novel compact limiting joint, drawing from double-parallelogram and umbrella-rib structures, enhancing control stability and force output. The drive system integrates electromagnetic coil parameter optimization (turns, voltage) for maximum jump distance using power transfer theory. Crucially, it exploits the hyperelasticity of polymer materials (e.g., rubber bands), where tensile strain increases their elastic modulus. A self-locking mechanism ensures targeted pre-stretching matches this high-stiffness phase, maximizing energy transfer efficiency. An FDM-3D printed prototype (330g mass) achieved a 6.5 m/s launch velocity and 2.9m jump distance. This robot demonstrates superior locomotion performance, control robustness, and terrain adaptability, validating its practical utility.