【正文】 in the past decades. Several techniques for weighting vehicles inmotion are now used including piezoelectric cables, capacitive mats, hydraulic and bendingplate load cells [1]. Hydraulic and bendingplate load cells offer high accuracy (1–5%) and dynamic range, yet suffer from high installation costs and size constraints. The piezoelectric and capacitive mat techniques are substantially lower in cost, yet are less accurate (5–15%) and do not function properly at speeds lower than 20 km/h [2] and [3]. To offer the required accuracy at reduced installation and maintenance costs, optic fiberbased WIM sensors are now being developed to improve, plement or even replace the ones currently in use. Based on the effect of polarization coupling between two orthogonally polarized eigenmodes of polarizationmaintaining fiber, Ansari et al. report on using highly birefringence polarizationmaintaining (HiBi) fiber for dynamic measurement of pressure with practical ramifications to the determination of weighinmotion of trucks [3]. Navarrete and Bernabeu report a multiple fiberoptic interferometer consisting of a MachZehnder interferometer configuration with one of its arms replaced by another MachZehnder interferometer [4]. Cosentino and Grossman developed a dynamic sensor using the microbend theory to test weightinmotion [5]. The present work describes the development of a dynamic pressure sensor based on the Michelson interferometer, which has simple structure, is cost effective and can potentially offer the high accuracy required for many applications. Special hardware and system software based on Labview WINDOWS/CVI are designed to implement the sensor functions, such as eliminating environmental noise, selftriggering of the test procedure and the fringe number and fringe period simultaneous count. Responses of the dynamic sensor are studied when subjected to dynamic pressive loads with different magnitudes and loading rates. Data calibration method is also researched to calibrate the sensor. 2. The sensor design . Sensor setup Fig. 1 illustrates schematically the proposed dynamic pressure sensor system. Singlemode optical fiber is used as a sensing element to form a Michelson interferometer. The optoelectronics ponents of the interferometer consist of a laser operating at wavelength of 1550 nm, a laser isolator and a photodiode. The sensor is made of munication grade optical fiber (Corning SMF28). The output signal from the detectoramplifier is first fed to a special hardware circuits including a twoorder high pass filter, a zeropoint detection circuit and a Schmitt Trigger circuit. The hardware circuits are designed to implement the following functions: (1) selfdiagnose the arrival time of the vehicle to selftrigger the measurement process。 附件 外文翻譯 Optic fiberbased dynamic pressure sensor for WIM system Shenfang Yuana, , , Fahard Ansarib, Xiaohui Liua and Yang Zhaob aThe Aeronautical Key Laboratory for Smart Materials and Structures, Nanjing University of Aeronautics and Astronautics, 29 YuDao Street, Nanjing 210016, China bDepartment of Civil and Materials Engineering, University of Illinois at Chicago, Illinois, IL 60607, USA Received 16 August 2020。 Weightinmotion。 (3) provide function to reduce the noise to a frequency band similar to the useful fringe outp ut of the Michelson interferometer. One possible source of this noise is caused by vehicles passing in a nearby lane. Since the output of the Michelson interferometer under pressure is fringe which can be considered as high frequency signal paring to the noise caused by temperature changes, laser and diode performance change and other low frequency environmental influences, a twoorder high pass filter was adopted to eliminate those low frequency ponents. A zeropoint detection circuit is designed to change the sineform fringe to pulse signal for the counter in the puter data acquisition system to count the fringe number and measure the f