Kienle Patrick, Batarilo Lorena, Akgül Markus, Köhler Michael H, Wang Kun, Jakobi Martin, Koch Alexander W
Institute for Measurement Systems and Sensor Technology, Department of Electrical and Computer Engineering, Technical University of Munich, 80333 Munich, Germany.
Sensors (Basel). 2020 Sep 1;20(17):4949. doi: 10.3390/s20174949.
Absolute distance measurement is a field of research with a large variety of applications. Laser triangulation is a well-tested and developed technique using geometric relations to calculate the absolute distance to an object. The advantages of laser triangulation include its simple and cost-effective setup with yet a high achievable accuracy and resolution in short distances. A main problem of the technology is that even small changes of the optomechanical setup, e.g., due to thermal expansion, lead to significant measurement errors. Therefore, in this work, we introduce an optical setup containing only a beam splitter and a mirror, which splits the laser into a measurement beam and a reference beam. The reference beam can then be used to compensate for different error sources, such as laser beam dithering or shifts of the measurement setup due to the thermal expansion of the components. The effectiveness of this setup is proven by extensive simulations and measurements. The compensation setup improves the deviation in static measurements by up to 75%, whereas the measurement uncertainty at a distance of 1 m can be reduced to 85 μm. Consequently, this compensation setup can improve the accuracy of classical laser triangulation devices and make them more robust against changes in environmental conditions.
绝对距离测量是一个有着广泛应用的研究领域。激光三角测量法是一种经过充分测试和发展的技术，它利用几何关系来计算到物体的绝对距离。激光三角测量法的优点包括其设置简单且成本效益高，在短距离内仍可实现较高的精度和分辨率。该技术的一个主要问题是，即使光机械装置有很小的变化，例如由于热膨胀，也会导致显著的测量误差。因此，在这项工作中，我们介绍了一种仅包含一个分束器和一个镜子的光学装置，它将激光分成测量光束和参考光束。然后，参考光束可用于补偿不同的误差源，如激光束抖动或由于部件热膨胀导致的测量装置偏移。通过大量的模拟和测量证明了这种装置的有效性。这种补偿装置将静态测量中的偏差提高了75%，而在1米距离处的测量不确定度可降低至85微米。因此，这种补偿装置可以提高传统激光三角测量设备的精度，并使其在环境条件变化时更具鲁棒性。
