AERODYNAMIC DISTURBANCE ON VEHICLE’S DYNAMIC PARAMETERS

Abstract

This research paper analysed the influence of aerodynamic disturbance on vehicle’s dynamic parameters. The vehicle dynamics were formulated from the Newton’s Second Law for modelling the vehicle. The vehicle was built using rigid body frames, mass and multi-body signal blocks of MapleSim2015 platform. Several vehicle masses were used to produce different vehicle dynamics with respect to the same aerodynamic drag and input force. Our analyses have shown that the mass of each vehicle is inversely proportional to the aerodynamic drag applied to it. At a given set-point of 25 ms-1 , the vehicle tracked the given speed exactly in the absence of the drag. However, for the lag in displacement, speed and acceleration were found as 25 m, 17 ms-1 and 0.3 ms-2 , respectively in the presence of drag with an average jerk of 45 ms-3 . This has provided an interesting insight on the effects of drag on the moving vehicle. The proposed vehicle was subjected to the same control strategy to form a twovehicle, look-ahead convoy as in conventional type. Improvements in the intervehicular spacing of 1.7 m, proper speed track, low acceleration(1.05 ms-2) and a suitable jerk of 0.04 ms-3 were achieved over the entire period (160 s) as compared to conventional vehicle. The proposed vehicle model scores higher accuracy than conventional vehicle on two-vehicle, look-ahead model and it has shown that the proposed model is more comfortable than the conventional one.

Keywords

• Acceleration
• Aerodynamic
• Jerk
• Position
• Vehicle speed