Extract

Abstract: In this study, the genetic algorithm method is adopted to optimise the ellipsoid parameters of
faceted reflector; i.e. solid angles of θ and ϕ, semi-latus rectum (d), and eccentricity (e). There are two types of reflector which designed in this study, those are divergent and convergent. Both designs are
verified through simulation with the target of illuminance (Eav) and uniformity (Ul) values, which
conform to the national standard for highway lighting. The approach of one-to-one mapping is used in
optimisation, thus one facet illuminates one target point precisely. From the optimisation stage, it is
yielded the ranges of θ angles from 0° to 36° (for divergent type) and 0° to 43° (for convergent).
Meanwhile for ϕ angles, it gave the ranges of 0° to 58° (divergent) and 0° to 85° (convergent). The d
values are ranged between 0.52 m to 0.66 m (for divergent type) and 0.53 m to 0.65 m (for convergent),
while the eccentricities have ranges from 0.95 to 0.98 (divergent) and 0.95 to 0.99 (convergent). From
final simulation, the values of Eav are varied from 22.2 lx to 70.3 lx with Ul = 0.4; which fulfilled the
standard requirements of minimal 20 lx and Ul = 0.2.

Keywords: Faceted reflector; solid angles; semi-latus rectum; eccentricity.

PDF

Download