High-Precision Angle Sensor Based on Angle Amplification via Double-Layer Regular Prism Structure

In this paper, a high-precision sensor for angle measurement with angle amplification based on the double-layer regular prisms structure was designed. The angle amplification was achieved by multiple reflections of the measurement laser between the inner and outer double-layer regular prism structure. The trajectory of the measurement laser within the double-layer regular prism structure was investigated, and a corresponding mathematical model was developed. A position-sensitive detector (PSD) measures displacement variations in the measurement laser and ultimately enables angle measurement by applying the displacement-to-angle conversion relationship derived from analysis of the reflection trajectory model. The sensor prototype achieved a measurement precision of ±0.5″. Additionally, the feasibility of the alternative measurement method using multiple measurement units was experimentally verified, while its measurement accuracy remained comparable to that of a single unit. The 360° angle measurement through proper arrangement of multiple PSDs can be achieved as well, and its feasibility has been discussed.