Frog-like robot with jump and walk mechanism for locomotion on rough terrain — Designing legs with biarticular muscles and slide-lock mechanism

The purpose of this study is to develop a frog-like robot that is able to avoid obstacles by jumping and walking on rough terrains by legs. There is no study that realizes both instantaneous jumping ability and precise control of leg joints in a single compact body. In this study, we refer to a musculoskeletal model of a frog and develop a leg mechanism that is designed to extend the leg instantly by a wire drive which is similar to a biarticular muscle of a frog. With this mechanism, two pins slide along with an L-form slot during wire tension, by which the joint swings to apply jumping force. We verified the mechanism by constructing an actual model and found that the joints could passively slide to the extending position by only applying tension on the wire for jumping. Calculation of necessary wire torque is also described.