Design and construction of a human powered vehicle seating simulator for diagnostic testing

Abstract

A seating simulator was built to test the influence of various seating positions on human cycling power output. The simulator measures a rider's physical stress required to produce a certain power output. A heart rate monitor is used to find the rider's physical stress level. The theory is that the best shaped seat will allow the rider to pedal most efficiently. The seat of the simulator can easily be changed by connecting the seat's support strings to a square grid of holes. Mechanical power flows from the simulator's bike pedals through a chain drive to an electric motor. Electrical power flows from the electric motor through a rectifier to a variable bank of resistors. There were issues which came up involving the bike parts used and the dynamics of the chain drive system. The worst problem was that the supports would flex causing the chain to slacken and resonate under the changing forces of the pedaling motion. First a steel pipe was added to make the system more rigid. Then a sliding copper derailleur was used to allow the chain to stay on up to 213 watts. Finally the copper derailleur was replaced with a bike's derailleur which allows the simulator to operate in excess of 450 watts. Initial tests of several different seat configurations were completed with notable influence on the heart rate of the rider.