Comparison study between static and dynamic responses of optical fiber weight in motion sensor

This research investigates responses of Optical Fiber Weight in Motion (WIM) sensors when static and dynamic weighing vehicle are applied. The vehicle used in the experiment was a replica of Mitsubishi FE 71 with weight of 23.01 kg. The WIM measurement system consisted of LED 1310 nm, optical fiber based WIM sensor, transimpedance amplified photodetector Ge PDA50 from Thorlabs, data acquisition DT translation 9816 S, speed sensors, and software program for WIM Evaluation. Static weighing was performed when the vehicle stopped. Besides performing static weighing on WIM sensor, measurement was also conducted on Kenko scale as validation. Meanwhile, measurement of dynamic weight was only conducted when the vehicle moved at a constant speed of about 1 km/h through WIM sensor. Experimental results showed two curves corresponded to the front axle load and the rear axle load. During static weighing, both WIM sensor and Kenko scales indicated similar output, which were flat curves. On the other hand, during dynamic weighing, WIM sensor had different output that was a pulse response. This preliminary study resulted in changes of amplitude and output shape. Unlike static weighing, moving vehicles contributed to the output of WIM sensor.