Amphibious Wheels with a Passive Slip Mechanism for Transformation

In a variety of missions, small sized robots are preferred due to their capability to maneuver and operate in tight spaces and voids. However, scaling down the size of robots impacts adversely on their ability to surmount larger obstacles on their path. A miniature robot operating in an unprepared environment has to face different kinds of terrains. Also, a fixed structure for locomotion does not allow for mobility across all surfaces. We propose a passive transformable wheel design that offers a multimodal (wheel-paddle-leg) design to adapt to operations in both land and water.The appendages were designed to act like paddles in water as well as allow the option to choose between legged or wheeled motion through a passive mechanism. A prototype of the wheel has been built and deployed on a testbed robot to validate the concept. The design has been shown to be feasible, albeit with refinement required in the design and manufacturing process for actual deployment. The results show that the wheel is capable of operating both on land and water with the passive mechanism successful in transitioning the wheel from legged motion to wheeled motion and vice versa.