Study On Multi-beam Detection System Based On Position-Sensitive Detector Phase Measurement

PSD (Position-Sensitive Detector) Phase Measurement Technology has advantages such as simple circuit, high-precision detection and good anti-jamming capability. So far, there are not many research reports about PSD Phase Measurement Technology. Phase Measurement Technology and frequency multiplexing is used in 3-D position and posture detection of small wall-climbing robot for multi-beam synchronous detection, which is able to simplify system and reduce costs. At the same time, it provides a new way to streamlined, low-cost and good anti-jamming multi-beam detection in the existing manufacturing process conditions.In this paper, the two theories about Horizontal Photoelectric Effect are summarized. On this basis, the principle of phase measurement is deduced basing on the RC transmission line model. Linearity between phase difference and position is proved using Matlab numerical simulation; Signal processing circuit and acquisition program is designed, the system is established and debugged. Single and multi-beam calibration and comparison is experimented, derivation is validated and some conclusion is obtained. Finally, Factors affect the phase measurement was also discussed. The idea of improving system performance and detection accuracy, as well as reducing the error is proposed.Experiments show that: There is obvious linearity between phase difference of the two electrodes and light position when incident light is sinusoidal modulated. The resolving power and error increases with modulation frequency, but linearity is contrary. There is mutual interference in multi-beam detecting. The less difference between modulating frequency, the much mutual interference, amount of incident light too. There is distortion in deviation from the midline of 2-D PSD. The more close to the edge of PSD, the more obvious distortion.