Optimization of the Roll and Steer Systems of a Four-Wheeled Tilting Vehicle

The work addresses the optimization of the steering and roll systems of an innovative four-wheeled tilting vehicle, which is currently being built at the University of Padova. The vehicle is a combination of traditional two and four-wheeled forms, with the driver operating a bike handlebar to steer, and throttle and brake inputs to control speed. Two pedals control the roll movement, while the gearshifts are made automatically. The steering system consists of a handlebar, column, pinion, rack and track-rods to the wheels. In the resulting spatial mechanism, roll and steer motions of the wheels are coupled. The kinematic optimization presented in this paper, aims at minimizing undesired roll to steer behaviour, and provides appropriate outer/inner wheel steer angles. The natural coordinate approach is employed to efficiently simulate and optimize the mechanism.