Multi-objective optimization of the light guide rod by using the combined Taguchi method and Grey relational approach

The light guide rod (LGR) is widely used to transmit light from a light emitting diode lamp. In this paper, a designed LGR for the application in the automobile lighting is prepared. The main factors that affect the LGR performances are the illuminance flux and uniformity. This paper aims to develop a method that optimizes the multi-objective parameters of the LGR. For statistical purposes, the experimental parameters for the LGRs are put in the L9(34) orthogonal array. In order to optimize these parameters, a method combining Taguchi method and Grey relational approach is established. The experimental results from illuminance flux and uniformity can be integrated into a single performance index. A comparison of the integrated performance index between the initial and optimal conditions shows that the illuminance flux increases from 1.14 to 1.42(lm) and the average difference from 1.46 to 1.07. The positive gains for the illuminance flux and the average difference value by this approach and compared with the initial condition are reported as 25.04 and 26.64 %, respectively.