System for weighing moving motor vehicles based on flexible sensors and fiber optics

Operating process of the deformation sensor measuring system for dynamic vehicle weighing using fiber optics, wherein the system comprises one or more weight sensor(s) (1) connected to an optical emission and detection equipment (2) via a multipath optical cable (C), the optical emission and detection equipment (2) being connected to an information processing and display equipment (5), and further comprising at least one presence sensor (3) and at least one temperature sensor (4) both connected to the information processing and display equipment (5), wherein the weight sensor (1) comprising an enclosure (1-E) made of a material selected from metal, plastic or composite, filled with a siliconized rubber damping material (1-G) which protects and insulates sensor reference components including a right input optical coupler (1-A-1), a left input optical coupler (1-A-2), a right optical reference (1-B-1), a left optical reference (1-B-2), a right output optical coupler (1-C-1), and a left output optical coupler (1-C-2), said reference components being mounted on a tray (1-H), and further comprising a right flexible rod (1-F-1) and a left flexible rod (1-F-2), made of resin and fiberglass, carbon or aramid composite material, fixed to the enclosure (1-E),

• wherein the process of operation of the system takes place in the following sequence:
• Aa) The input coupler (1-A-1) and (1-A-2) divides the optical signal generated by a photo-emitter (2-A);
• the portions of this division are directed to optical sensors (1-D-1) and (1-D-2) for the optical references (1-B-1) and (1-B-2);
• the vehicle, when transiting over the apparatus, exerts forces on the pavement in such a way that these are transmitted to the right flexible rod (1-F-1) and left flexible rod (1-F-2), which are proportionally flexed;
• the aforementioned rods, in turn, transmit the stress suffered to optical sensors (1-D-1) and (1-D-2), but not to the optical references (1-B-1) and (1-B-2);
• the signals from the optical sensors (1-D-1) and (1-D-2) and the optical references (1-B-1) and (1-B-2) are interfered with and the resulting signal emitted by the right output optical coupler (1-C-1) and/or left output optical coupler (1-C-2) is proportional to the forces exerted on the pavement and captured by a photodetector (2-B);
• Ab) A photodetector (2-B) circuit transforms the signal from the optical to the electrical domain and has adjustable gain, which allows losses in the optical path to be compensated;
• the electrical signal is routed to a high-pass filter (2-C);
• Ac) The high-pass filter (2-C) removes the low frequencies that cause the electrical signal to fluctuate as a function of temperature;
• this filtered signal, plus a known DC current level generated via a clamper (2-D), is routed to a buffer (2-E);
• Ad) The buffer (2-E) transfers a signal from a high-impedance region to a low-impedance region, transmitting the resulting signal in parallel to a peak follower (2-F) and to a Schmitt trigger (2-H);
• Ae) The peak follower (2-F) generates a signal copy of the envelope of the signal emitted by the buffer (2-E), which is forwarded to a reference generator (2-G);
• Af) The reference generator (2-G) generates dynamic reference voltages, which are based on percentages of the voltage intensity of the signal envelope generated by a peak follower (2-F);
• these voltages are used as comparison levels for the Schmitt trigger (2-H);
• Ag) Using the signals from processes (Ad) and (Af), the Schmitt trigger (2-H) generates a binary sequence with the same phase and frequency as the signal captured in process (Aa);
• and
• Ah) Finally, the binary signal together with the signals from a presence sensor (3) and a temperature sensor (4) are sent to the information processing and display equipment (5).