Transition to Paw/Hoof in Bio-Inspired Quadruped Robot TB-Horse II and Its Demonstrative Simulation

The TB-Horse II is a bio-inspired quadruped robot with biological features of the breed Mangalarga Marchador. The main target of this paper is to verify the possibility of the robot to make the transition to paw/hoof during its movementsthroughthegaitmarcha.Inthisstudy, thetransition is the process of retracting the end joints, which are the feet of robot's legs, forming something similar to a paw or hoof that increase the ground contact area of the robot. The swingleg retraction allows the TB-Horse II to walk on soft ground or sandy terrain, because the normal position of the legs creates an excessive pressure and can sink into the sand. The transition to paw/hoof is carried out in three steps defined as gaitmarcha, gaitmarchaintransitionandpaw/hooflocomotion. In the first step, the TB-Horse II uses the gait marcha as a walking pattern. The swing-leg retraction is performed in the second step. In the third step, the robot moves using the gait marcha, but with the paw/hoof already formed. However, in this step, the movements of the gait marcha is changed due to the curvature of the paw/hoof formed and increase the contact area with the ground. Finally, the three steps are implemented and validated in the simulation software called Virtual Robot Experimentation Platform (V-REP).