Study on Roller-Walker (system integration and basic experiments)

Abstract

We have proposed a new leg-wheel hybrid mobile robot named 'Roller-Walker'. Roller-Walker is a vehicle with a special foot mechanism which changes to a sole in walking mode and a passive wheel in skating mode. On rugged terrain the vehicle walks in leg mode, and on level or comparatively smooth terrain the vehicle makes wheeled locomotion by roller-skating using the passive wheel. The characteristics of Roller-Walker are: 1) it has a hybrid function but is lightweight, 2) it has the potential capability to exhibit high terrain adaptability in skating mode if the control method for roller-walking is fully investigated in the future. In this paper, the 2 leg trajectory for straight roller-walking is optimized in order to achieve the maximum constant velocity. Also a changeable ankle mechanism was integrated into the Roller-Walker system. Experiments were performed to demonstrate the validity of the concept of Roller-Walker and the results of straight roller-walk experiments are compared with those derived through simulation.