Failure risk assessment in autocollimation-based small-angle measurement systems: a hybrid FMEA model combining fuzzy logic and analytic hierarchy process

The autocollimation-based small-angle measurement system (ASAMS) is a widely used precision instrument in industrial applications. However, domestically produced ASAMS currently exhibit a reliability gap compared to their international counterparts, limiting their ability to meet the increasing demands of various industries. To address this issue, this study conducts a thorough Failure Mode and Effects Analysis (FMEA) on ASAMS to identify critical failure modes. A multi-level fuzzy comprehensive evaluation framework, which integrates fuzzy logic and the Analytic Hierarchy Process, is developed to quantitatively assess fault risks. The evaluation results indicate that the lighting system and optical sensing system exhibit the highest risk levels, both classified as moderate-risk subsystems. Targeted improvements, including the use of high-performance components and optimized assembly designs, are recommended to mitigate measurement failures in these critical subsystems. This systematic approach provides actionable solutions to enhance the reliability and precision of domestically developed autocollimation instruments.