Optimization of Chassis Design Parameters, Braking and Stability Analysis of Autonomous Vehicles on Elevated Guideway

Abstract

In the development of the PRT (Personal Rapid Transit) systems every detail, ranging from autonomous vehicle dimensions to dynamic performance in the longitudinal (acceleration and braking) ride (vertical and pitch motions) and handling require rigorous study and research to make the system successful as their counterparts (normal cars) moving on the roads. The supposedly enclosing guideway can make analysis more intricate with its confounding surface properties and geometry. The thesis work here proceeds with the dimension estimation the context of which is to propose the autonomous vehicle geometrical dimensions including the wheel base, track width and height, the centre of gravity height which is certainly the most recognized parameter influencing almost all the vehicle performances. The dimension estimation is divided into four major steps. The modus for the dimension estimation is to employ optimized performance equation, for instance optimal braking equation, vehicle dynamic index, rollover threshold and estimation of vehicle size with given centre of gravity height. Continuing with the performance analysis, braking ability of the vehicle was thought to be principal reason behind the stability and hence analyzed subsequently. The optimal braking performance of the PRT system is analyzed and the suitable braking system conforming to the requirement is proposed. For further considerations on the chassis design, the wheel loads especially the amount of load transfer have been discussed in detail with given vehicle data and operating conditions. Also, another important criterion is the risk for overturning and sliding of a vehicle due to wind disturbance, especially the vehicle with high centre of gravity and narrow wheel track during standstill on banked curves. A simple analysis of the guideway design has been proposed with given operating conditions, which is regarding the maximum allowed guideway deflection, support columns spacing and the vehicle top speed. Ride performance as the other major area regarding the human comfort is analyzed and the required suspension stiffness and damping of the autonomous vehicle is estimated using ADAMS. Looking in the fact that the PRT system in discussion here travels on a smooth metallic guideway with nominal surface roughness elevation, two other combinations namely, vehicle without suspension system and vehicle without suspension system but the springs beneath the car seat is analyzed on ADAMS view. At the end the future work is discussed and the report concludes with the discussion and references.