With an intense competitive automotive environment, it becomes
imperative for any OEM to launch their products into the market in
a short span of time & with a 'First Time Right'
approach. Within the current scenario in the Automotive Industry,
the selection of optimum set of hard points and wheel geometry
often becomes an iterative or a trial and error process which is
both time consuming and involves higher development cost as there
may be instances where 2 to 3 sets of iterations are needed before
specification is finalized for production. Through this paper, an
attempt has been made to develop a methodology for deciding wheel
geometry parameters (covered in the later section of this paper
like Caster, Camber, Mechanical trail, etc.) for a three wheeled
vehicle as a First Time Right (FTR) approach to cut down on
conventional, expensive & time-consuming iterative approach. In
this paper, we have studied the parameters which affects the
directional stability and steering effort using a multi body
dynamics (MBD) model and validated it with a series of experiments
on prototype three wheeled vehicles. In a three wheeled vehicle the
design of front suspension system is very critical as the steering
system or the handlebar is often an integral part attached to the
same front wheel. The problem definition was approached by carrying
out a literature review and identifying the parameters affecting
steering effort. Parametric studies were carried out through
simulation to understand the effect on handlebar steering effort.
The primary objective of this dissertation is to highlight the
systematic approach carried out during full vehicle dynamics
analysis to identify key wheel geometry hard-points which influence
the steering effort and ride feel for the customer. Similarly, the
impact of the above listed parameters can be gauged by the fact
that it directly effects the directional stability of the vehicle.
The outcome of this study was validated on the actual test vehicle
to confirm its universal applicability. Through this paper we have
attempted to bring forth new design considerations for a suspension
steering linkage geometry in a three-wheeler vehicle which, we
feel, will be useful for future reference of similar system
architecture. Key words: Original Equipment Manufacturer (OEM),
Three wheeled vehicle, Steering effort, Shimmy, Directional
stability, Multi Body Dynamics (MBD).