Human-in-the-Loop Bicycle Control via Active Heart Rate Regulation

This paper addresses the design of a heart rate (HR) control system for a bicycle equipped with a continuously varying transmission. The control system helps the cyclist maintain a constant physical effort throughout the trip. A complete model of the entire system (bicycle, cyclist, and HR dynamics) is derived, identified, and validated using experimental data. The model is the basis for the development of two controllers. A proportional-integral controller and a second-order sliding mode (SOSM) controller. The two controllers are analyzed, concluding that the SOSM controller offers better robustness against unmodeled dynamics and disturbances. The SOSM controller is finally exhaustively tested on two subjects in real-world conditions. With the proposed systems, the riders are capable of keeping their HR within 10 bpm from the desired one.