Thermal Stability Analysis and Optimal Design for a Two-Dimensional Angle Sensor

What is it about?

The two-dimensional angle sensor based on autocollimator princple has been widely uesd in the precision measurement field for pitch and yaw error motions of a moving object. A compact angle sensor is develpoed, which consists of a laser diode, a polarization beam splitter, a quarter-wave plate, a focusing lens, a plane mirror and a quadrant-photo detector. The signal drift of this sensor affects the measured angle and is mainly caused by the change in enviromental temperature. To improve the thermal stability of the sensor, the thermal-structure coupling was analyzed using finite element analysis software of ANSYS 16. Simulation results show that it is more stable for the angle sensor to adopt the mechanisms with symmetrical structure. A modifided optimal angle sensor is thus developed. The stability experiments show that, compared with the original one, the average drift of the optimized angle sensor is reduced from 0.430 arcssec/°C to 0.120 arcsec/°C when the variation of the enviromental temperature is 5 °C. The optimized angle sensor is better for high precision measuring equipment.

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