Wheel transformer: a multi-terrain robot with passive transformable wheels

Abstract

In this paper, the design, optimization, and performance evaluation of a new wheel-leg hybrid robot are reported. This robot utilizes a novel kind of transformable wheel for its locomotion to combine the advantages of both circular wheels and legged wheels. To minimize design complexity, this new transformable wheels transformation process is operated passively, which eliminates the need for additional actuators. A new triggering mechanism is also employed to increase the success rate of the transformation. To maximize the climbing ability in the legged-wheel mode, the design parameters of the transformable wheel and the robot are tuned based on behavioral analyses. The performance of our new development is evaluated in terms of stability, energy efficiency, and the maximum height of the obstacle the robot can climb over. By virtue of this transformable wheel, the system could climb over an obstacle 3.25 times as tall as its wheel radius, not compromising its driving ability at 2.4 body lengths per second with the specific resistance of 0.7 on flat surfaces.