桥梁工程中非接触位移测量技术研究综述

Review on research of non-contact displacement measurement technologies in bridge engineering

系统总结了视觉测量、微波雷达与激光测振这3种非接触位移测量技术的测量方法、测量原理与工程应用影响因素,阐述了非接触位移测量技术在桥梁工程动位移测量、模态识别、索杆张力测试中的创新成果,探讨了非接触位移测量面临的关键挑战与后续研究发展方向。分析结果表明:非接触位移测量方法能够实时获取桥梁结构动位移、自振频率、模态振型等信息,测试精度受硬件、算法、测量距离和环境条件等多重因素影响;视觉测量技术易低成本实现面内多目标位移的实时测量,但对环境条件变化较为敏感,且一般应设置靶标,适用于短距离长期或远距离短期情形下的位移监测;微波雷达具有抗天气干扰能力强、测量距离远(可达2 km)、成本可接受、全天候全天时工作、可长期监测等特点,一般也需设置角反射器提高径向位移测试精度;激光测振技术具有微米级位移测量精度,且抗电磁干扰能力强,但难以实现远距离多点同步测量,穿透性较差,易受天气影响,且设备昂贵,适用于短期径向位移监测;应针对桥梁结构监测时长、测量距离、环境条件、单(多)点监测需求、测量精度要求等的不同,选用合适的非接触测量方法;未来可通过提高硬件系统性能提升远距离多点同步测试能力,发展各种自适应环境(光照、大气)扰动校正算法提高位移测试精度和可靠性,将视觉测量、微波雷达、激光测振等技术与加速度计、全站仪、GPS等测试手段进行多源信息融合,通过相互校准减少不确定性,提升不同环境条件下的测量稳健性,实现全天候三维测试。

The measurement methods,principles,and influencing factors during engineering applications of three non-contact displacement measurement technologies were systematically summarized,such as the visual measurement,microwave radar,and laser vibration measurement.The innovative achievements of non-contact displacement measurement technologies in the dynamic displacement measurement,modal identification,and cable tension testing in bridge engineering were introduced.Moreover,the key challenges faced by the non-contact displacement measurement and future research directions were discussed.It is found that non-contact displacement measurement methods can obtain real-time dynamic displacement,natural vibration frequency,modal shape,and other information about bridge structures.The measurement accuracy is affected by multiple factors such as the hardware,algorithm,measurement distance,and environmental conditions.The visual measurement technology makes it easy to achieve real-time in-plane displacement measurement of multiple targets at a low cost,but it is sensitive to change in environmental conditions and generally requires target installation.Therefore,it is suitable for short-distance and long-term or long-distance and short-term displacement monitoring.The microwave radar has the characteristics of strong anti-weather interference capability,long measurement distance(up to 2 km),acceptable cost,all-weather all-time operation,and longterm monitoring.Generally,corner reflectors are needed to improve the accuracy of radial displacement measurement.The laser vibration measurement technology has the micrometer-level displacement measurement accuracy and strong resistance to electromagnetic interference.However,it is difficult to achieve long-distance and multi-target synchronous measurements with poor penetration and is easily affected by environmental conditions.In addition,its equipment is expensive,and thus it is suitable for short-term radial displacement monitoring.Suitable noncontact measurement methods should be selected according to different needs of bridge structures for long-term and short-term monitoring,measurement distance,environmental conditions,single(multiple)target monitoring,and measurement accuracy.In the future,the ability to perform long-distance and multi-target synchronous measurements can be enhanced by improving the performance of the hardware system.Various disturbance correction algorithms for adaptive environments(lighting and atmosphere)can be developed to improve the displacement measurement accuracy and reliability.Furthermore,it is necessary to integrate the visual measurement,microwave radars,and laser vibration measurement technologies with testing methods such as accelerometers,total stations,and global position system(GPS)for multisource information fusion,thus ensuring mutual calibration to reduce uncertainty,improving the measurement robustness under different environmental conditions,and achieving all-weather three-dimensional testing.1 tab,12 figs,153 refs.