The torque control of human power assisted electric bikes

This paper investigates the issues of torque control strategies for light electric bike systems with human power assistance. The feature of this electric bike equipped with both usual electrical machine power and personal-dependent human power makes its operation distinct from other types of vehicle. To facilitate a reliable and smooth torque control design, a speculation of the human torque exerted during electrical bike's motion is proposed as function of the desired velocity and actual vehicle velocity. Then, three torque control strategies are formulated, termed the manual control, proportional control, and assistant control, respectively. The assistant control approach is proposed in this work as a control signal to compensate the disturbance torque, which comprises the human torque and the resistance torque from various sources, including the wind, the tire, and the gradient angle. Also, three control laws based on these three control strategies are presented, and the evaluation of these control laws is conducted via time response simulation.