Design and Control of an All-in-the-Wheel Assisted Kick Scooter

Traffic congestion, energy efficiency, and environmental issues are fueling the interest in light electric vehicles. In particular, electric human-powered hybrid vehicles are compelling because of their low cost, ease of use, lightweight, and extremely small footprint. This paper presents an electrically assisted kick scooter. Most electric scooters are throttle-controlled; this makes them electric vehicles, and as such, they may require driving licenses. The proposed design solves this limitation by introducing the electrically assisted kick scooter concept. The proposed design does not have any human-machine interface device. It controls the electric assistance in a transparent way. The user operates the vehicle as a passive scooter, while the control system smoothly delivers the assistance. The proposed solution is based on several functional modules: a kick detection algorithm, a closed-loop control of the vehicle velocity, a brake detection algorithm, and an online parameter estimator that makes sure that the vehicle behaves consistently no matter the road surface. The details of the control system are discussed in the paper, and an extensive experimental validation based on metabolic and electric measurements shows that the electric assistance cuts in half the effort necessary to operate the vehicle with an average battery consumption of 4 Wh/km.