Development of a tilt control method for a narrow-track three-wheeled vehicle

The space and weight savings provided by narrow tilting vehicles could make them a solution to the pollution and congestion problems seen in urban environments. The success of this new type of vehicle relies heavily on the control method used to balance the vehicle in corners. A tilting three-wheeled vehicle was developed at the University of Bath as part of an EU-funded project. The original direct tilt control method implemented on the prototype was shown to perform well in steady state, but rapid transients were shown to potentially lead to instability. A new type of controller was therefore required to reduce the load transfer across the rear axle during transient state manoeuvres. This paper presents a linearized model of the tilting vehicle system which is used to optimize a new tilt controller in the frequency domain. The controller, which uses combined steer and tilt control inputs, is shown to significantly reduce transient roll moments compared to the previous control method. This results in a much safer and more predictable handling characteristic.