Estimation of pedaling torque for electric power assisted bicycles

Since electric power assisted bicycles have been released in Japan, their sales are increasing. However the prices are high because they are equipped with an expensive torque sensor to measure human pedaling torque to assist human by an electric motor. The purpose of this study is to develop an external power assist systems applicable for a normal bicycle that fits in the Japanese regulation. This paper proposes an instantaneous pedaling torque observer based on the disturbance observer and the fourier filtering in order to decouple the load torque and the pedaling torque. The validity of the proposed method is confirmed by numerical simulations and experiments.