Presentation and assessment of rideability of a novel single-track vehicle: the Anaconda

Abstract

In this paper, a new single-track vehicle, the Anaconda, is presented and modelled according to a multibody theory. This articulated vehicle begins with a traditional bicycle, called the head module, followed by a succession of so-called pedal modules (PMs) equipped with one rear-steered wheel. Each module is connected to the preceding one by a spherical joint. To assess its dynamic behaviour, the model of an Anaconda with two PMs is simulated under the EasyDyn framework, a multibody library based on the minimal coordinates approach. The simulation of such a vehicle cannot be performed without the riders’ action, consisting of the torques applied on the handlebars. The latter is implemented through controllers designed by optimal control, from the out-of-plane dynamics of the vehicle going straight ahead at 20 km/h. First, two optimal controllers are determined separately for the Head Module alone on one hand and for the Pedal Module alone on the other hand. They are then implemented on the Anaconda and it appears that the vehicle is close to instability and that the handling of the pedal modules is delicate but humanly possible. Finally, the difficulty in riding the Anaconda is evaluated through the so-called rideability index, which increases, as expected, with the amount of PMs, and shows that good psycho-motor skills will be needed to drive the Anaconda.

Keywords:

• multibody
• bicycle dynamics
• single-track vehicle
• optimal control
• path following
• rideability

Acknowledgements

The authors thank the Belgian Development Agency (Belgian Technical Cooperation) for the doctoral grant of the second author, and the Lycée Technique Maurice Herlemont of La Louvière for the construction of the prototype.

Notes

For the purpose of illustration, the script related to the HM is given in Appendix.