This paper describes dimensional synthesis, analysis and
performance optimization of a three-link rigid-axle suspension
system. This suspension architecture has two longitudinal links and
panhard rod as a transverse link. In case of rigid axle with three
links, roll stiffness is primarily governed by springs, anti-roll
bar, suspension link dimensions and its orientations. Because of
suspension architecture, the bushings connecting the longitudinal
link to axle will also contribute to the suspension roll stiffness.
Typically, this contribution is comparable to the contribution due
to the suspension springs. Hence, this paper explores the process
of reducing roll stiffness of three-link rigid-axle suspension by
identifying and changing high impact parameters. In the multi-step
process, the first step is to evaluate the kinematics and
compliance performance. This analysis is performed using
"ADAMSĀ®" - the multibody dynamics analysis software. Out
of all kinematics performance parameters, roll stiffness is one of
the major parameters which has significant effect on ride and
handling characteristics of vehicle. Handling performance of a
vehicle is a critical performance attribute defining and
differentiating a vehicle from its competitors.
Typically, with such suspension architecture, problem of excess
rear roll stiffness is common. Reduction in spring stiffness is not
an option as its specification is governed by other vehicle
performance viz. ride comfort, load capacity, etc. Hence, a
detailed study has been performed to understand the governing
design variables and its sensitivity to the performance metrics (in
the present case, the roll stiffness). The prominent design
variables that have been studied are Side view axle bush
separation, Side view longitudinal link inclination, and Top view
axle side bush separation (between LH and RH). With these design
variables DOE is performed using Taguchi Method of orthogonal
array. The results of this study have been presented to aid
intuitive inferences. The key benefit of this study is with minimum
number of experiments understanding sensitivity of the governing
design variables and therefore a definite dimensional synthesis
procedure to design a required suspension performance.