Fig. 1. Measurement principle of one-dimensional PSD sensor

Fig. 2. Distribution of one-dimensional coordinates of light spot and 4-PSD sensor coordinate system

Fig. 3. Principle diagram for 4-PSD fusion measurement

Fig. 4. PSD signal processing and acquisition circuit design scheme

Fig. 5. Signal conditioning circuit

Fig. 6. Schematic diagram and calibration devices of 4-PSD measuring system

Fig. 7. Man-machine interface of 4-PSD measuring system

Fig. 8. Photo of 4-PSD experimental setup

Fig. 9. Laser modulation to remove ambient light interference effect

Fig. 10. Error analysis of 4-PSD measurement

Fig. 11. Signals after adding variety of filtering algorithms

Fig. 12. One-dimensional PSD linear distortion

Fig. 13. Changes in plane displacement and angle rotation before calibration

Fig. 14. Relationship of PSD1 output and horizontal XY axis linear motion

Fig. 15. Changes in plane displacement and angle rotation after linear correction

Fig. 16. Circular trajectory map after first-order fitting

Fig. 17. Circular trajectory map after second-order fitting

Fig. 18. Angle rotation change after polynomial fitting

Fig. 19. Accuracy distribution in 4-PSD device measurement

Fig. 20. Distribution surface of 4-PSD measurement system error

Fig. 21. Distribution contour of 4-PSD measurement system error