The Cycab robot: a differentially flat system

The Cycab robot is a new mobile platform already used in several research labs and meant for different applications such as public transportation in airport terminals, self-service cars in pedestrian zones, etc. From a kinematic point of view, the Cycab specificity is the turning of its rear wheels as a linear function of the steering angle of the front wheels. This feature enhances the maneuverability of the Cycab in cluttered environments. However, the associated kinematic model is new and different from the ones commonly treated in the robotics literature( such as the car-like, tractor-trailer, etc). To our knowledge such a system has not yet been studied and especially, there is no existing motion planner for this system. In this paper, we tackle the study of this new nonholonomic system, by establishing its kinematic model and proving its differential flatness property. From this study we deduce a first motion planner for the system.