Akama, S., Murayama, Y., and Sakoda, S., "Torque Control of Rear Wheel by Using Inverse Dynamics of Rubber/Aramid Belt Continuous Variable Transmission," SAE Int. J. Engines 6(4):2100-2109, 2013, doi:10.4271/2013-32-9042.
This paper concerns a torque control of a rear wheel of a motorcycle equipped with a rubber/aramid belt electronically-controlled continuous variable transmission where a primary sheave position is controlled by an electric motor. In particular, the paper discusses a method to calculate a required engine torque and a required primary sheave position, given reference values of a rear-wheel torque and an engine rotational velocity. The method forms a foundation of a hierarchized traction control where a higher control layer decides an optimal motorcycle motion (rear-wheel torque and engine rotational velocity) and a lower control layer realizes the motion by actuators (engine torque and primary sheave position). Difficulties of the control are due to large mechanical compliance of the rubber/aramid belt, which leads to an inevitable lag from the primary sheave position to a speed reduction ratio. Taking into account the compliance, the proposed method compensates rotational kinetic energy and losses of the transmission to improve accuracy of the control.