Study of the forward locomotion of a three-dimensional multibody model of a Waveboard by inverse dynamics

Abstract

This paper studies the forward motion of the Waveboard, a variant of the Skateboard that consists of two platforms and two caster wheels. This system exhibits a very interesting propelling mechanism, since the rider can achieve a forward motion by means of an oscillatory lateral motion of the platforms, without touching the ground.Because of the complex nature of the Waveboard dynamics, a three-dimensional multibody model is proposed, modeling the wheels as two rings first and as tori later on. Some holonomic constraints arise at the contact of the wheels with the ground, while some non-holonomic constraints appear from the assumption of rolling without slipping. The equations of motion of the system are derived and a kinematic and inverse dynamics simulation of a realistic meandering trajectory is carried out, in order to understand the necessary forces and torques to obtain the desired motion. Moreover, an analysis of the influence of the design parameters on the external actions exerted by the rider is made.Finally, the multibody model is enhanced by modeling the wheels as two tori, performing a comparison between the ring and toroidal models.