基于位置敏感探测器的六自由度精密位姿测量系统

位置敏感探测器(Position Sensitive Detector,PSD)是一种高精度的二维位移测量传感器,利用三片二维PSD的组合实现空间六自由度相对运动的位移和角度测量。测量系统主要包括三片PSD传感器(包括PSD光敏面和发光管)、低噪声的信号调理和AD采集电路,采用三片PSD正交布局方案,通过PSD光敏面的光点位置计算相对运动的位移和角度。设计了六自由度的PSD标定测试系统,用于PSD测量系统中心偏移和发光管安装误差的标定测试。测试结果表明,PSD测量系统的测量范围优于位移±10mm、角度±2.5°,标定后PSD测量系统的噪声误差为位移0.1mm、角度0.02°,测量系统的绝对位移误差小于0.5mm、角度误差小于0.14°,满足系统0.5mm和0.5°的指标要求。此外,对PSD传感器的环境适应性进行了评估。PSD测量系统具有量程宽、精度高、线性度好的优点,成功应用于天舟1号货运飞船微重力主动隔振装置的相对运动测量中。

Six-degree-of-freedom displacement and angle measurement system based on two-dimensional position-sensitive detector

A Position-Sensitive Detector (PSD) was used to measure two-dimensional displacement with high precision. A combination of three two-dimensional PSDs can implement measurements of six-degree-of-freedom relative displacement and angle. The measurement system mainly comprises three PSD sensors (including PSD photosensitive surface and light-emitting tube), low noise signal conditioning, and an Analog to Digital(AD) acquisition circuit. Three PSD orthogonal layout schemes were used to calculate the displacement and angle of relative motion through the spot position of three PSD photosensitive surfaces. A six-degree-of-freedom PSD calibration and test system was designed for the calibration of the PSD measurement system center offset and light tube installation error. The test results show that the measurement range of the PSD measurement system is better than ±10 mm and ±2.5°. The noise error of the PSD measurement system after calibration is 0.1 mm and the angle is 0.02°, while the absolute displacement error of the measuring system is less than 0.5 mm and the angle error is less than 0.14°. This proves that the system meets the requirements of 0.5 mm and 0.5°. In addition, the environmental adaptability of the PSD sensor was evaluated. It can satisfy the system requirements of noncontact, online, real-time, higher precision, and rapid speed, as well as strong anti-jamming and stabilization. The system is successfully used in the space microgravity active vibration isolation system of the Tian Zhou 1 cargo ship for relative motion measurement.