Modeling of a Wind-Turbine-Powered Ground Vehicle

A number of vehicles have been demonstrated in past years that are purely wind-powered and capable of propelling themselves upwind into an oncoming wind. A wind turbine mounted on the vehicle drives the wheels of the vehicle through a geartrain. To help understand the vehicle operation, this paper presents a dynamics model of such a vehicle, using a blade-element momentum theory model of the turbine. As a case study, we use the Blackbird vehicle which set an upwind speed record in 2012. The model is able to accurately predict the vehicle performance in upwind mode when compared to available experimental data. Once validated, the model is used to determine how the Blackbird could be refined to improve its performance. In particular, we find that a variable-ratio transmission could substantially improve the vehicle’s acceleration; and that using lower gear ratios would slightly improve its terminal velocity. A sensitivity analysis performed on the losses (rolling resistance, air drag and transmission efficiency) found that improvement in the transmission efficiency would lead to the greatest increase in terminal velocity.