SYSTEM FOR WEIGHING MOVING MOTOR VEHICLES BASED ON FLEXIBLE SENSORS AND FIBRE OPTICS

Abstract

The present invention corresponds to a weigh-in-motion system for motor vehicles based on flexible, fiber-optic sensors. The field of application of the patent object is the measurement of dynamic physical events that are caused directly or indirectly by the passage of a motor vehicle over the sensors. This system consists of 5 blocks: an information processing and display equipment (5) is connected to an optical emission and detection equipment (2), one or more presence sensors (3), a temperature sensor (4), and one or more weight sensors (1). It has advantages over other technologies, such as: simplified manufacture and compact size, sensors immune to electromagnetic interference, long service life, and the possibility of being installed on different types of pavement.

Claims

1. IN-MOTION WEIGHING SYSTEM FOR MOTOR VEHICLES BASED ON FLEXIBLE SENSORS AND FIBER OPTIC, consisting of: one or more weight sensor(s) (1) connected to an optical emission and detection equipment (2) via a multipath optical cable (C); an optical emission and detection equipment (2) connected to an information processing and display equipment (5); a presence sensor(s) (3) and a temperature sensor (4) both connected to the information processing and presentation equipment (5), characterized by, a weight sensor (1), composed of an enclosure (1-E) made of a material chosen from metal, plastic or composite, filled with a siliconized rubber damping material (1-G), which protects and insulates the sensor's reference components: a right input optical coupler (1-A-1), a left input optical coupler (1-A-2), a right optical references (1-B-1) and a left optical reference (1-B-2), a right output optical coupler (1-C-1), and a left output optical coupler (1-C-2) from vibrations and impacts; the aforementioned reference components are mounted on a tray (1-H); 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, are fixed to the casing (1-E); the weight sensor (1) is connected to the optical emission and detection equipment (2) via a multipath optical cable (C).

2. WORKING PROCESS OF THE IN-MOTION WEIGHING SYSTEM FOR MOTOR VEHICLES BASED ON FLEXIBLE SENSORS AND FIBER OPTIC, according to claim 1, from the effects inherent in the phenomenon of optical interferometry: phase, frequency and/or intensity (and their variations) of the optical wave, characterized by the weight sensor (1) capturing and making useful, the physical efforts proportional to the dynamic weight under evaluation.

3. OPERATING PROCESS OF THE DEFORMATION SENSOR MEASURING SYSTEM FOR DYNAMIC VEHICLE WEIGHING USING FIBER OPTICS, according to claim 1, characterized in that, the process of operation of the system of the present patent 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).

4. (canceled)

5. IN-MOTION WEIGHING SYSTEM FOR MOTOR VEHICLES BASED ON FLEXIBLE SENSORS AND FIBER OPTIC, which the assembly (M), of the weight sensor (1), takes place in the following sequence: M1) Testing the continuity of the optical fibers inside the rods (16) with a laser pen; if the rod is suitable, remove excess wax and varnish it; M2) Separate the enclosure (1-E); M3) Mount the tray (1-H) inside it; M4) Glue the rods (16) to an upper right end of the base of the enclosure (1-E-D) and to a upper left end of the base of the enclosure (1-E-E) with cyanocrylate; complemented by the following stages characterized by: M5) Separate the multipath optical cable (C) at one end, strip off a piece, glue the stripped end of the multipath optical cable (C) to a lower right end of the enclosure base (1-E-C); M6) Position the input optical couplers (1-A-1) and (1-A-2), output optical couplers (1-C-1) and (1-C-2) and two optical reference sections (1-B-1) and (1-B-2) on the tray (1-H) and splice the optical components; M7) Fill the enclosure with cushioning material (1-G), siliconized rubber, and glue an enclosure cover (1-E-2) to an enclosure base (1-E-1) with epoxy resin-based two-component adhesive; M8) Wait for the adhesive to fully cure and test the sensor; M9) Apply heat shrink to regions the upper right end of the base of the enclosure (1-E-D) and to the upper left end of the base of the enclosure (1-E-E) and to the lower right end of the enclosure base (1-E-C); and M10) Identify the sensor with the serial number and store in an appropriate place.

Description

[0038] The following figures are attached for a better understanding of the present patent:

[0039] FIG. 1 shows the detailed block diagram of the system covered by this patent;

[0040] FIG. 2 shows the general block diagram of the system covered by this patent;

[0041] FIG. 3 shows the block diagram of the software process carried out by the system of the present patent;

[0042] FIG. 4 shows the assembly of the enclosure (1-E) of the weight sensor (1) of the present patent;

[0043] FIG. 5 shows the top view of the installation of the weight sensor (1), temperature probe (4-A), presence probe (3-A) and other equipment used in the system of the present patent;

[0044] FIG. 6 shows the transparent perspective view of the weight sensor (1) of the present patent installed on the pavement (P);

[0045] FIG. 7 shows the cross-sectional view I of FIG. 8, of the weight sensor (1) of the present patent;

[0046] FIG. 8 shows the cross-sectional view II of FIG. 8, of the weight sensor of (1) of the present patent;

[0047] FIG. 9 shows the cross-sectional view III of FIG. 8, of the weight sensor (1) of the present patent;

[0048] FIG. 10 shows the results of the manufacturing stages of the weight sensor (1) of the present patent; and

[0049] FIG. 11 shows the components used in the manufacturing process of the weight sensor (1) of the present patent.

[0050] The sensor in this patent also has the following advantages: [0051] Simple production method; [0052] Compact size; [0053] It works by detecting the phase of the optical wave and does not suffer from interference; [0054] Long service life; [0055] Can be installed and integrated into any type of road surface; and [0056] Made of a material that is not harmful to vehicles when removed from the pavement.

[0057] According to FIG. 2, the in-motion weighing system for motor vehicles based on flexible sensors and fiber optic is made up of weight sensor(s) (1) connected by a multipath optical cable (C) to an optical emission and detection equipment (2); optical emission and detection equipment (2), connected in parallel to a presence sensor(s) (3), and a temperature sensor (4) and all are connected to an information processing and display equipment (5).

[0058] As shown in FIGS. 1 and 6, a weight sensor (1) consists of a right input optical coupler (1-A-1) and a left input optical coupler (1-A-2) of the double taper coupler or planar waveguide coupler type, but not limited to these, connected unidirectionally to a right optical reference (1-B-1) and a left right optical reference (1-B-2), a right optical sensor (1-D-1) and a left optical sensor (1-D-2) and via a multipath optical cable (C) to a photoemitter (2-A); a right optical reference (1-B-1) and a left optical reference (1-B-2), made of optical fiber material, connected unidirectionally to the right input optical coupler (1-A-1) and left input optical coupler (1-A-2) and to a right output optical coupler (1-C-1) and a left output optical coupler (1-C-2); a right output optical coupler (1-C-1) and a left output optical coupler (1-C-2), of the double taper coupler or planar waveguide coupler type, but not limited to these, connected unidirectionally to the optical references (1-B-1) and (1-B-2), to the optical sensors (1-D-1) and (1-D-2) and via the multipath optical cable (C) to a photodetector (2-B); a right optical sensor (1-D-1), of the single or multi-mode optical fiber type, connected unidirectionally to the right input (1-A-1) and right output (1-C-1) optical couplers, and a left optical sensor (1-D-2), of the single or multi-mode optical fiber type, connected unidirectionally to the left input (1-A-2) and left output (1-C-2) optical couplers; an enclosure (1-E) made of a choice of metal, plastic or composite material, filled with a siliconized rubber damping material (1-G), which protects and insulates the sensor's reference components: input optical couplers (1-A-1) and (1-A-2), optical references (1-B-1) and (1-B-2), and output optical couplers (1-C-1) and (1-C-2) from vibrations and impacts; such reference components are mounted on a tray (1-H); 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 are fixed to the enclosure (1-E); the weight sensor (1) is connected to an optical emission and detection equipment (2) via a multipath optical cable (C).

[0059] As shown in FIG. 1, an optical emission and detection equipment (2) consists of a photoemitter (2-A) of the light-emitting diode LED or laser diode type, but not limited to these, connected unidirectionally to the right (1-A-1) and left (1-A-2) input optical couplers via a multipath optical cable (C); a photodetector (2-B), of the avalanche type, but not limited to this, connected to an output optical coupler (1-D) of the weight sensor (1) via the multipath optical cable (C); a high-pass filter (2-C), of the active or passive type, analog or digital, connected after the photodetector (2-B); a clamper (2-D), active or passive, analog or digital, connected after the high-pass filter (2-C); a buffer (2-E), active or passive, analog or digital, connected to the damper (2-D); a peak follower (2-F), active or passive, analog or digital, connected to the buffer (2-E); a reference generator (2-G), active or passive, analog or digital, connected to the peak follower (2-F); and a Schmitt trigger (2-H), active or passive, analog or digital, connected in parallel to the buffer and reference generator (2-G).

[0060] A presence sensor (3), which consists of a presence probe (3-A), of the inductive loop type, but not limited to this, connected to a processor (3-B) which interfaces with the variables provided by a presence trigger (GP) and a speed (V) trigger, as shown in FIGS. 1 and 3.

[0061] A temperature sensor (4) consists of a temperature probe (4-A), of the digital or analog thermometer type, but not limited to these, which is connected to a processor (4-B) that interfaces the temperature variable (T), as shown in FIGS. 1 and 3.

[0062] An information processing and display equipment (5) connected to the emission and detection equipment (2), presence sensor (3) and temperature sensor (4) and consists of an information processing machine, computer or dedicated system with a processor with a recorded logic program. This machine contains a logic program specially developed for the operation of the system covered by this patent. The program interfaces frequencies, signals emitted by sensors, generating the data and results desired by the inventor.

[0063] The computer program is inserted into the information processing and display equipment (5), and its process is as follows (FIG. 3): [0064] 5.a) The binary signal coming from the Schmitt trigger (2-H) is captured via an analog-to-digital converter or edge-sensitive input pins. The instantaneous frequencies of the phase-varying signal, which are the inverse of the time difference between the rising and falling edges of this signal, are stored in a frequency vector; [0065] 5.b) A peak frequency detection algorithm is applied to the frequency vector, which describes the exact moment when a wheel/axle is over the weight sensor (1). The detected peak frequency is time-stamped and a duration window, fixed or not, is opened around it; [0066] 5.c) Each windowed wheel/axle is integrated and the value resulting from the integration is an input variable for the weight estimation curve; [0067] 5.d) With the integration values obtained in 5.c), the temperature variable (T), obtained by processor (4-B), and the speed (V), obtained by processor (3-B), the axle weight is calculated; [0068] 5.e) With the axle weight values obtained in 5.d) and the distance between axles, it is possible to calculate the weight per axle group; and [0069] 5.f) Finally, with the weight values per axle group, obtained in 5.e), and the moments when the vehicles start and end temporally, presence triggers (GP), obtained by processor (3-B), it is possible to calculate the total gross weight.

[0070] The set of sensors, weight sensor(s) (1), presence sensor(s) (3) and temperature sensor (4), are installed in the pavement as shown in FIG. 5. The installation configuration of the system's sensors can follow the format shown in FIG. 5 or other positioning variations. When a vehicle travels through a monitoring region (RM), the pavement temperature and the signals proportional to axle weight and vehicle speed are transduced, the aforementioned signals are sent to the information processing and display equipment (5). After mathematical processing, the weight per wheel, per axle, per axle group and the total gross weight of the vehicle are recorded.

[0071] FIGS. 5, 6, 7, 8 and 9 exemplify the installation of the sensor on the pavement, showing in detail the sections (I, II, III) with the system components installed: a pavement (P), a rod depth (PH), a trench width (LT), a trench depth-rod section (PTH), a resin (R), flexible rods (1-F-1) or (1-F-2), enclosure (1-E), multipath optical cable (C), a trench depth-casing section (PTI), a multipath optical cable width (LC), also showing the monitoring region (RM) and a traffic direction (ST).

[0072] The system in this patent works in the following sequence: [0073] Aa) The input coupler (1-A-1) and (1-A-2) splits the optical signal generated by the photoemitter (2-A). The portions of this division are directed to the optical sensors (1-D-1) and (1-D-2) for the optical references (1-B-1) and (1-B-2). As the vehicle passes over the apparatus, it exerts forces on the pavement (P) 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 flexed proportionally; the rods (1-F-1) and (1-F-2), in turn, transmit the effort suffered to the 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 (P) and captured by the photodetector (2-B); [0074] Ab) The 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); [0075] 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 by a clamp (2-D)) is fed to a buffer (2-E); [0076] 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 the peak follower (2-F) and to a Schmitt trigger (2-H); [0077] 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); [0078] 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 the peak follower (2-F). These voltages are used as comparison levels for the Schmitt trigger (2-H); and [0079] 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). Finally, the binary signal is sent to the information processing and display equipment (5). The weight sensor (1) and its manufacture, are described through the steps of base manufacture Fb), of rod manufacture Fh) and of sensor assembly M), (referencing FIGS. 4, 10 and 11) which are defined below:

[0080] Base Manufacture Fb): [0081] Fb1) Cut three rectangles of carbon fiber, glass or aramid, one rectangle of plastic, one rectangle of shading cloth and one rectangle of peel ply; [0082] Fb2) Wax the upper face of a lower mold (9) and remove excess wax with a polisher; [0083] Fb3) Stick a double-sided tape (10) marking out a rectangular area in the center of the lower mold (9). Position a plastic coil (8) on one side and attach a vacuum control system (7) inlet hose; [0084] Fb4) In the center of the area marked out in Fb3), apply three alternating layers of fibrous blanket and epoxy resin. At the top of the stack, apply the peel ply and a shading screen (12). Finish the assembly by sealing the system with a plastic vacuum screen (11) glued to the double-sided tape (10); [0085] Fb5) Close the mold, start the vacuum control system (7) and a temperature control system (6). The vacuum must be maintained for 30 to 40 minutes. The temperature-controlled curing process has stages which are described in Table 1; and

TABLE-US-00001 TABLE 1 Timings of the temperature control steps in the curing process. Control step A B C D Initial temperature (? C.) 30 80 80 100 Final temperature (? C.) 80 80 100 100 Duration (minutes) 60 60 60 120 [0086] Fb6) After the temperature-controlled curing process has finished, wait for the system to reach room temperature. Open the mold, remove the plastic (11), shading screen (12) and peel ply. Remove the manufactured base plate (13) and set it aside on a bench. Remove the plastic spiral (8), the double-sided tape (10) and the vacuum control system hose (7).

[0087] Rod Manufacture Fh): [0088] Fh1) Using a template, mark out the areas where the optical fibers will be positioned and the cutting areas. Remove the template and resin the optical fiber over the marked areas. Reserve a base plate with optical fibers (14); [0089] Fh2) Cut three rectangles of fiber blanket (carbon, glass or aramid), one rectangle of plastic, one rectangle of shading fabric and one rectangle of peel ply; [0090] Fh3) Stick double-sided tape (10) marking out a rectangular area in the center of (9). Position a plastic coil (8) along the length of one of the sides and attach the intake hose of the vacuum control system (7); [0091] Fh4) In the center of the area demarcated in Fh3), assemble the base plate with optical fibers (14) and apply four alternating layers of epoxy resin and three of fibrous blanket. On top of the stack, apply a peel ply and a shading mesh. Finish the assembly by sealing the system with a plastic vacuum screen (11) glued to a double-sided tape (10); [0092] Fh5) Close the mold, start the vacuum control system (7) and the temperature control system (6). The vacuum must be maintained for 30 to 40 minutes. The temperature-controlled curing process has stages which are described in Table 1; [0093] Fhb) After the temperature-controlled curing process has finished, wait for the system to reach room temperature. Open the mold, remove the plastic (11), shading screen (12) and peel ply. Remove the final plate (15) and set aside on the bench. Remove the plastic spiral, double-sided tape and vacuum system hose; and [0094] Fh7) Cut the areas demarcated in Fh1) using a suitable cutting process (water jet, laser, emery, or by blades). The result of the cut is the production of rods (16), which can be used as right (1-F-1) or left (1-F-2) flexible rods.

[0095] Assembly M) of the weight sensor (1) takes place in the following sequence: [0096] M1) Test the continuity of the optical fibers inside the rods (16) with a laser pen; if the rod is suitable, remove excess wax and varnish it; [0097] M2) Separate the enclosure (1-E); [0098] M3) Mount the tray (1-H) inside it; [0099] M4) Glue the rods (16) to an upper right end of the base of the enclosure (1-E-D) and to a upper left end of the base of the enclosure (1-E-E) with cyanocrylate; [0100] M5) Separate the multipath optical cable (C) at one end, strip off a piece, glue the stripped end of the multipath optical cable (C) to a lower right end of the enclosure base (1-E-C); [0101] M6) Position the input optical couplers (1-A-1) and (1-A-2), output optical couplers (1-C-1) and (1-C-2) and two optical reference sections (1-B-1) and (1-B-2) on the tray (1-H) and splice the optical components; [0102] M7) Fill the enclosure with cushioning material (1-G), siliconized rubber, and glue an enclosure cover (1-E-2) to an enclosure base (1-E-1) with epoxy resin-based two-component adhesive; [0103] M8) Wait for the adhesive to fully cure and test the sensor; [0104] M9) Apply heat shrink to regions the upper right end of the base of the enclosure (1-E-D) and to the upper left end of the base of the enclosure (1-E-E) and to the lower right end of the enclosure base (1-E-C); and [0105] M10) Identify the sensor with the serial number and store in an appropriate place.