A Wheel-legged Robot with Active Waist Joint: Design, Analysis, and Experimental Results

This paper presents a wheel-legged robot that features an active waist joint. The proposed wheel-legged robot is composed of a front module, a rear module, and an active waist joint. The proposed robot can perform rectilinear motion and turning motion in both wheeled and legged modes. The active waist joint module is added to make the robot pass through the curved narrow channel. Several experiments have been done to evaluate the performance of the proposed wheel-legged robot. The maximum velocities of the proposed robot in wheeled and legged modes are 17.2 and 10.4 m/min respectively. And the average corresponding deflection rates of the proposed robot in wheeled and legged modes are 3.1 and 3.7 % respectively. The mobility efficiencies of the robot in wheeled and legged modes are up to 96.3 and 94.3 % respectively. Compared with the proposed robot in legged mode, the performance in the turning motion with the active waist joint is better when the proposed robot is in wheeled mode. Two approaches of climbing obstacles are proposed for the proposed robot in legged mode. The wheel-legged robot can climb an obstacle with maximum height of 10 cm.