Pedalling Comfort of a Custom Pedal Series Hybrid Drivetrain in a Cargo E-Tricycle

Abstract

A Pedal Series Hybrid Drivetrain (PSHD) uses an electrical power transmission rather than a chain, belt, or shaft. It creates exciting opportunities for the vehicle's design, but pedalling does not always feel comfortable. This study evaluates the pedalling comfort of a custom PSHD in an electric cargo tricycle. In this PSHD, pedal-drive generator converts human mechanical power to electrical power that is used by two hub motors to propel the vehicle. The pedal-driven generator is mechanically decoupled from the propulsion of the vehicle. Therefore, natural pedalling is replicated using a custom programmable controller for the mechanical resistance of the generator. Test subjects reported a very comfortable pedalling feeling, however slightly different from the feeling of a traditional e-bike. They failed to explain the differences in more detail. Further measurements show that the pedal generator of the PSHD has the same power cycle as the pedals in a traditional e-bike, but the pedal generator has a greater variation in the instantaneous angular velocity.