Human machine interfacing issues in SeNZA, a Series Hybrid Electric Bicycle

Traffic congestion, energy and environmental considerations are boosting the interest for Light Electric Vehicles. Electrically Power Assisted Cycles (EPAC's) show a great potential: they are cost effective, safe, easy to use and have a small footprint. In this paper, we present SeNZA a Series Hybrid Electric Bicycle. Designing a Series Hybrid Electric Bicycle poses several challenges; in this work, the issue of Human Machine Interface is addressed. Pedals are, at the same time, the interface and a power source; it is therefore critical to provide a natural feeling and intuitive control. The proposed solution is based on two nested cadence control loops. The inner loop makes the pedaling smooth; the outer loop is used to impose a desired behavior to the pedals and to interpret the cyclist's command. The robustness and efficacy of the proposed solution are proven through a linear analysis and human-in-the-loop experimental validation.