Robust optimization of an automobile rearview mirror for vibration reduction

An automobile outside rearview mirror system has been analysed and designed to reduce vibration with a finite element model, Modal analysis is conducted for the calculation of natural frequencies. Harmonic analysis is utilized to estimate the displacements of the glass surface under dynamic loads. The model is verified with the vibration experiment for the parts and the assembled body. The structure of the mirror system is optimized for robustness defined by the Taguchi concept. At first, many potential design variables are defined. Final design variables are selected based on the amount of contribution to the objective function. That is, sensitive variables are chosen. The signal-to-noise (S/N) ratio in the Taguchi method is replaced by an objective function with mean and standard deviations of the quality characteristics. The defined objective function is appropriate for structural design in that the vibration displacements are minimized while the robustness is improved.