After analyzing and reasoning from all aspects in view of ergonomics,such as human’s influences and problems when bicycle on moving,a unique patent product: low seat,straight pedaling and swing bicycle is developed.

The bicycle s pedal cranks keep indifferent equilibrium state when they stay in the free state,so that they can bring about disturbance between people and machines.

Analysis of stress and stiffness of the treadling force measurement device by F.E.M.;