Hardware design for an electro-mechanical bicycle simulator in an immersive virtual reality environment

Roughly 50,000 people are injured in bicycle collisions with motor vehicles each year. The Hank Bicycle Simulator provides a virtual environment to study and reduce this tragic loss by safely investigating the interaction of bicycle riders and traffic, particularly for bicyclists crossing streets. The bicycle simulator design focuses on the bicycle and rider inertia, the predominant dynamic element for riders moving from a stopped position. The Hank Bicycle Simulator’s flywheel provides instantaneous inertial response while a servomotor provides simulated wind resistance to pedaling. This work describes the simulator design and a validation experiment that compares the simulator performance to theoretical predictions. The Hank Bicycle Simulator achieved initial acceleration with less than 0.20% error at realistic rider weights. The observed terminal velocity achieved less than 3.75%, with smaller errors for heavier riders. This allows the rider to cross a street with about a 60 ms time difference between the simulator and a real-life rider pedaling at a constant propulsive force. The Hank Bicycle Simulator was also validated through various physical experiments measuring the system inertia, the time delay of the electrical components, and the overall system performance. Such careful system validation for a mechanical feedback system is relatively rare in simulation research and is unique among previous reports of bicycle simulators.