ITVR20120116A1 - VERIFICATION DEVICE FOR VERIFICATION OF ONE OR MORE ELECTRONIC DEVICES WITH LOOP DETECTOR. - Google Patents

Description

TEST DEVICE FOR TESTING ONE OR MORE DEVICES

ELECTRONIC LOOP DETECTOR

DESCRIPTION

The present disclosure refers in general to the sector of electronic devices which operate with sensors based on magnetic loops. More specifically, but not exclusively, these sensors are intended to acquire traffic information. More particularly, the present disclosure relates to a verification device for the verification and certification of inductance detection units, so called loop detectors, which operate with, for example are connected to, inductance variation sensors including magnetic loops.

This disclosure also relates to a method for verifying and certifying said loop detectors or inductance detection units.

It is known in the state of the art that the verification and certification of inductance detection units, called â € œloop detectorâ €, intended to acquire a signal generated by magnetic loops placed on a road for traffic detection, are based on a procedure carried out directly in the field. This procedure requires that the loop detector to be tested is connected to magnetic loops positioned on a busy road: taking advantage of the natural passage of vehicles. To examine the operation of the loop detector; the values provided in output by the device (such as vehicle speed) are compared with those provided by certified measurement systems used simultaneously with the loop detectors or inductance detection units under examination.

At the basis of this disclosure, there is a recognition by the inventors of this patent application that, in the state of the art, no procedures or tools are used to avoid field tests, and to certify inductance detection units in the laboratory before installation on the road, ie by means of an off-line procedure.

In other words, the inventors of the present patent application have recognized that the state of the art leaves open the problem of providing a system / instrument that allows loop detector tests and certifications to be carried out directly in the laboratory, without requiring field tests. that require the passage of vehicles on magnetic loops positioned on the carriageway, that is, in a way independent of the actual passage of vehicles.

On the basis of this recognition and the related technical problem, a verification device as defined in claim 1 and a method for verifying a loop detector or inductance detection unit as defined in independent claim 12 are made available.

Secondary characteristics of the object of this disclosure are defined in the corresponding dependent claims.

The device according to the present disclosure is a device for the verification and certification of inductance detection units (loop detector), in which this device is able to accurately reproduce the electro / physical behavior of the inductive loops when they are affected by the passage of vehicles, namely those magnetic loops used to acquire traffic information. In particular, in accordance with this disclosure, the verification device is able to reproduce the electrical-physical behavior of the inductive loops when they are affected by the passage of vehicles, and to send the magnetic fingerprints to the electronic boards under test (loop detector). notes which must correspond to the same number of measurements made by the loop detector under test stimulated by the verification device.

The function of the verification device according to the present disclosure is to generate known magnetic fingerprints, similar to those obtainable through the traffic detection loops, and thus allow the test and certification of the loop detectors (or inductance detection units ) automatically in the laboratory or in any other place, without requiring field installation.

In practice, in accordance with this disclosure, the verification device is capable of emitting a `` nominal '' simulation signal, which reproduces the signal emitted by the inductive loops, such that when the signal is `` read '' by the loop detector, the reading signal, or â € œrealâ € signal, should correspond to the â € œnominalâ € simulation signal. In the event of a lack of correspondence / coincidence between the â € œnominalâ € simulation signal and the reading signal or â € œrealâ € signal, a malfunction of the loop detector / inductance detection unit can be established in the laboratory.

This device according to the present disclosure allows to avoid extensive field tests and allows to calculate a priori a time interval for carrying out the tests, since such tests are not entrusted to the randomness of the passage of vehicles. In fact, with the device according to the present disclosure, it is possible to reproduce in rapid succession the magnetic fingerprints of a predefined set of selected vehicles.

A consequence of carrying out tests in the laboratory, not conditioned by the passage times of real vehicles, can be, for example, a reduction in the costs of the labor required to supervise the measurements. The use of the verification device according to this disclosure allows in practice to significantly reduce the costs for the verification and certification phase of the loop detectors, as all the operations can be performed in the laboratory, or in general in a place independent of the vehicle passage area (i.e. not in the field), and possibly in a rapid and automated manner.

The verification device according to the present disclosure can also allow to increase the quality of the tests to which the loop detectors are subjected with respect to the tests carried out in the field. In fact, through the electronic device it is possible to generate a test plan or program that includes all the magnetic fingerprints (profiles) of the desired vehicles, and all the transit speed values. The high number and exhaustiveness of the configurations that can be used for the tests allow the loop detectors to be subjected to remarkably effective tests, if compared to those obtainable through tests carried out in the field; the latter are in fact subject to randomness and it is not possible to guarantee the verification of the loop detectors in all the necessary scenarios (types of vehicles and transit speeds).

In some embodiments, the verifying device is capable of simulating the signal coming from a selected set of vehicles. In this embodiment, the verification device is put in connection with a library of simulation signals from which the signals correlated to the chosen set of vehicles are selected.

The present invention therefore finds application in the field of testing and certification of electronic cards (loop detectors) for the acquisition of vehicle fingerprints provided by the magnetic loops used for traffic detection.

Magnetic loops are sensors that rely on inductance variations. In some embodiments, the device can be used in all applications where it is necessary to simulate the responses of sensors based on inductance variations, for example to reproduce the behavior of the magnetic loops used in metal detectors.

According to some embodiments of the present disclosure, the verification device is able to simulate the electro / physical behavior of the inductive loops which are coils, and as such they are characterized by the following parameters: inductance (L), series resistance / parallel, and / or series / parallel capacitance. Therefore, by synthetically reproducing these parameters by means of an appropriate electronic device, it is possible to emulate the behavior of the magnetic loops, made for example in the asphalt and affected for example by the passage of vehicles.

According to some embodiments of the present disclosure, the verification device includes a series of output stages, each of which includes a signal transformer. For example, the transformer includes a primary circuit which is stimulated by a constant current generator to obtain an inductance variation on a secondary circuit due to the effect of magnetic induction. The secondary stage can be made available to be connected to the loop detector to be tested: in fact, from the electrical point of view, the simulator is seen exactly as a real turn (two wires without electrical potentials that lead to a winding).

In other embodiments according to the present disclosure, the device comprises, as output stages, generators of variable inductance made with active or passive electronic components. In particular, according to these embodiments, the verification device includes a hardware device, a firmware (which resides on this device) and a high-level software for managing the verification device, for example, by means of a management and control unit, such as an external personal computer (PC) interfaced with it.

In some embodiments, the hardware component of the verification device includes an electronic board with a series of output channels (for example between one and four outputs) with variable inductance, and an input interface for connection to a personal computer (PC) external. The hardware component of the verification device can be governed by a microcontroller that takes care of the communication with the PC and the management of the digital electronic components present in the measuring device. In particular, the microcontroller can drive a high resolution analog digital converter, used to impose the current on the primary circuit of the transformers present on the output stages. It is possible to set both the inductance to be operated by the simulator (for example the same of the turns to be simulated), and the dynamics to be given to the output signal in correspondence with the magnetic fingerprint being simulated. It follows that according to these embodiments, the verification device, from the hardware point of view, can be considered to all effects as an "arbitrary function generator", with a series of controlled inductance outputs. Furthermore, in some embodiments it is possible to provide for the use of an external PC to check high-level functions relating to the tests to be performed and those useful for the periodic calibration and certification of the verification device. This external PC can be connected to the verification device in order to interact through a user interface (screen, keyboard, mouse). A software set up on the external PC can be used to automate the tests performed by the verification device; for this purpose, the developed software is also able to read the data detected by the loop detectors under test. In practice, in accordance with some aspects of the present disclosure, a measurement system is provided, for example a closed loop system and including a verification device, a loop detector and an external PC in which the verification device is interposed. between the external PC and the loop detector. Using this `` ring '' measurement system it is possible to send to the loop detector under test a large quantity and variety of known magnetic fingerprints generated by the verification device, to which as many equal or proximate measurements detected by the loop detector under test must correspond.

Other advantages, characteristics and methods of use of the object of the present disclosure will become evident from the following detailed description of some of its preferred embodiments, given by way of non-limiting example. However, it is evident that each embodiment can present one or more of the advantages listed above; in any case, each embodiment is not required to simultaneously present all the listed advantages. Reference will be made to the figures of the attached drawings, in which:

Figure 1 illustrates a diagram of a signal transformer according to an embodiment of the present disclosure;

Figure 2 illustrates a system including a measurement system according to an embodiment of the present disclosure;

Figure 3 illustrates a block diagram of a verification device according to a further embodiment of the present disclosure.

With reference to the attached figures, reference number 101 indicates, by way of example, a verification device according to an embodiment of the present disclosure. In particular, the device 101 according to the present disclosure is adapted to simulate the behavior of magnetic coils or coils, which are inductors intended, for example, for detecting traffic.

In particular, the device 101 is based on the fact that the loops for traffic detection are coils (inductors), and as such they are characterized by one of the following parameters: inductance (L), resistance in series / parallel, capacitance in series / parallel, or a combination thereof.

It follows that, by synthetically reproducing these parameters by means of an appropriate electronic device, it is possible to emulate the behavior of the magnetic loops made in the asphalt and affected by the passage of vehicles.

The device 101 includes a signal transformer 10 (illustrated in detail in Figure 1), which, in the exemplary embodiment, includes a primary circuit 12, including N1 turns wound on a core 19. The primary circuit 12 is stimulated via a power generator 14.

The signal transformer 10 includes a secondary circuit 16 including N2 turns wound on the core 19, and provided with an output 17. When energy is supplied to the primary stage / circuit 12, due to the effect of magnetic induction a magnetic flux 18 which induces a voltage across the output 17 in the secondary circuit 16.

In other words, the control device 101 includes a signal transformer 10, as schematically illustrated in Figure 1, in which a primary circuit 12 is stimulated by means of a constant current generator 14 to obtain an inductance variation on the secondary circuit 16 due to the effect of magnetic induction. According to another aspect of the present disclosure, with reference to Figure 2, the secondary stage, or secondary circuit 16, is made available to be connected to the loop detector 40 to be tested: in fact, from the electrical point of view, the signal transformer, which in fact it is a simulator, it is seen exactly as a real turn (two wires without electric potentials that lead to a winding).

Figure 3 illustrates a device 101 in a more elaborate embodiment comprising one or more output stages or secondary circuits 16, which is based on the use of variable inductance generators made with signal transformers. With respect to this solution, the verification device 101 according to the present disclosure makes it possible to guarantee perfect compatibility and isolation with any input stage of the loop detector devices to be tested. In practice, the device 101, like the one illustrated in figure 3, is of the adaptable type and can be connected to different loop detectors to be tested.

Even more particularly, with reference to Figure 3, the device 101 according to the present disclosure includes a hardware component comprising an electronic card with a series of output channels, for example from one to four outputs (17a, 17b, 17c, 17) with variable inductance, adapted to be connected to the loop detector devices 40 to be controlled, and of a communication interface 25 (for example but not exclusively of the USB type) for connection with an external personal computer 26.

The device 101 includes a microcontroller 27 which is in charge of communication with the personal computer 26 and of the management of the digital electronic components present in the device 101 itself. In particular, the microcontroller 27 drives a digital analog converter 28, in the example with high resolution, used to impose the current on the primary circuit 12 of the transformers present on the output stages 17a, 17b 17c 17d. It is possible to set both the inductance at which to operate the simulator (for example the same of the turns to be simulated), and a specific dynamics to be given to the output signal in relation to the magnetic fingerprint being simulated.

Even more particularly, in the alternative embodiment illustrated in Figure 3, the device 101 includes four signal transformers 10 each comprising the four output ports 17a, 17b 17c 17d which are characterized by a variable inductance, for example by way of example and not limitative, it can vary from 70 Î1⁄4H to 600 Î1⁄4H. In this regard, it should be noted that the range of values can be much wider depending on the needs and specific cases, and can be established from time to time. Each transformer 10 includes a current generator 30, which can be driven by an analog signal imposed by the digital analog converter 28. The resolution of the digital analog converter, through which the inductance is (indirectly) varied, is, in the example of realization illustrated, it has 16 bits and is able to operate at very high frequencies (compared to practical needs).

All operations are governed by the microcontroller 27, which, as mentioned, also takes care of the communication with the personal computer 26 through the communication interface 25. The microcontroller 27 is equipped with an oscillator, to ensure synchronism, and with a programming port (for loading a firmware).

Furthermore, the device 101 includes a buffer, so as to allow the reception via communication interface of four different waveforms (one for output channel 17a, 17b 17c 17d), and to generate them in a perfectly synchronous way and in the domain weather.

The precision of this procedure is guaranteed by a local quartz and is therefore independent of the asynchronous flow of the communication interface. This particular data management allows to obtain a synchronization in the generation of magnetic fingerprints so as not to generate errors on the simulated â € œspeedâ € of the vehicles.

In particular in this regard, the following is noted.

The traces of the waveforms, which must be reproduced on the output ports 17a, 17b, 17c, 17d, can be loaded via the input communication port 25. Loading can take place in a serial manner while the outputs on ports 17a, 17b, 17c, 17d can take place in parallel. For this reason it appears convenient that the asynchronous data flow coming in from the communication port 25 is buffered in the device 101 and then the traces are sent to the ports 17a, 17b, 17c, 17d in a perfectly synchronous way (so once all the traces have been stored in device 101). In fact, synchronism errors in sending the traces to the output ports 17a, 17b, 17c, 17d could cause simulation errors on the speed of the vehicle. In fact, if we consider that to detect the speed of a vehicle it is convenient to use the traces of at least two loops (= at least two traces generated on the doors 17a, 17b, 17c, 17d), it follows that, if there were synchronism errors on the signals at the gates 17a, 17b, 17c, 17d, errors would be induced on the simulated speed detected by the loop detectors 40 connected to the gates 17a, 17b, 17c, 17d of the device 101.

The device 101, in the embodiment illustrated here, from a hardware point of view, can be considered to all effects as an "arbitrary function generator", with a series of controlled inductance outputs.

The high-level functions relating to the tests to be carried out and those useful for periodic calibration and certification from the 101 device are instead realized through a software that resides on the personal computer 26, and which uses a user interface (screen, keyboard, mouse ). This software is used to automate the tests performed by the device 101 according to this disclosure: for this purpose, the software developed is also able to read the data detected by the loop detectors under test.

It follows that the device 101 according to the present disclosure can be part of a closed or loop system 100 for checking the loop detector devices, such as the one illustrated by way of example in Figure 2.

Thanks to this automatic measurement `` ring system '' (Figure 2), it is possible to send to the loop detector under test a high quantity and variety of known magnetic fingerprints generated by the 101 device, to which as many equal measurements must correspond. or next detected by the loop detector device under test. All the characteristics that in some way can determine the precision of the instrument (of the variable inductance, in the signal generation times, etc.) are limited to the hardware section and are not affected by the performance of the host PC, which, in this form of implementation illustrated by way of example, it is mainly used as a user interface / mass memory, and as an engine for the automation of the test.

According to further aspects of the present disclosure it is possible to manage the device 101 by means of one of the following operating steps or a combination of these operating steps.

Parameterization phase.

In this parameterization phase, the characteristics of the loops to be simulated are set, such as for example the inductance and / or the dynamics of the signal, in which different values can be set for each channel, in order to simulate also loops of the type different.

Test and diagnosis phase.

In this test and diagnosis phase, a self-diagnosis and calibration of the verification device is carried out. In particular, functions are provided to generate known signals in DC (fixed inductance values) or AC (signals, ramps, patterns at known frequencies, real passages, etc.) useful for verifying the accuracy of the verification device using external calibration systems. .

Management phase of references of magnetic tracks.

In this phase of managing references of magnetic tracks, a library of known magnetic fingerprints is used that can be used to set up automatic tests (the samples to be generated can be imported in digital format (numerical patterns) from other environments and instruments).

Test library management phase,

In this test library management phase, test cycles are managed which consist in making the test device 101 generate a series of virtual vehicle passes whose number, class, speed, length can be freely programmed. (for example, it is possible to create a test where it is possible to simulate the passage of 1000 cars at different speeds (known), 100 motorcycles, 100 cars with trailers, etc., possibly mixed together).

Verification phase

In this verification phase it is possible to choose the desired configuration from the test library and to start the test cycle. (in this way the acquired parameters for each sample sent will be read from the loop detector, and at the end of the test a comparison will be made between each sample emitted by the device 101 and the relative data detected by the loop detector device, in order to determine the number of magnetic fingerprints recognized incorrectly to estimate the tolerances of the loop detector.

The object of the present disclosure has hitherto been described with reference to preferred embodiments. It is to be understood that other embodiments may exist which pertain to the same inventive nucleus, all falling within the scope of the protection of the claims annexed hereafter.

Claims (19)

CLAIMS 1. Verification device (101) for the verification of one or more electronic loop detector devices (40) or inductance detection units, in which said electronic loop detector devices are adapted to operate with, and / or are adapted to be connected to sensors based on one or more magnetic loop, and in which the verification device includes a signal simulator (10) adapted to emulate a behavior of said one or more magnetic loop and / or reproduce a signal of said one or more more magnetic coil. Verification device (101) according to claim 1, wherein said one or more electronic loop detector devices (40) are used to acquire traffic information and said magnetic loops are affected by the passage of vehicles. 3. Verification device (101) according to claim 1 or 2, wherein said signal simulator is adapted to emulate the behavior of a magnetic loop and / or reproduce a signal of said one or more magnetic loop, in which said loop magnetic is intended as two wires without electric potentials that lead to a winding. Verification device (101) according to any one of the preceding claims, wherein said signal simulator (10) is adapted to emit a signal based on at least one of the following parameters or combination of parameters: inductance (L), resistance in series / parallel and / or series / parallel capacitance. Verification device (101) according to any one of the preceding claims, wherein the signal simulator is a signal transformer (10) including a primary circuit (12) adapted to be stimulated by means of a current generator (14) , and a secondary circuit (16) provided with an output (17), in which in a condition in which the primary circuit (12) is supplied with electric current, and, due to the effect of magnetic induction, a magnetic flux ( 18) induces a voltage at the output (17) in the secondary circuit (16). 6. Verification device (101) according to claim 5, wherein the secondary circuit can be connected with said one or more electronic loop detector devices (40). Verification device (101) according to any one of the preceding claims, wherein the signal simulator includes one or more signal transformers (10) having variable inductance output stages. Verification device (101) according to claim 7, including a digital to analog converter (28), which drives the one or more signal transformers (10) to vary an inductance. 9. Combination of a verification device according to any one of the preceding claims and said one or more electronic loop detector devices (40). 10. Measurement system comprises a verification device (101) according to any one of claims 1 to 9, a management and control unit (26) and one or more of said electronic loop detector devices (40). 11. Measurement system according to claim 10, wherein said verification device (101), said management and control unit (26) and said one or more of said electronic loop detector devices (40) are connected together in a ring configuration and in which, in said ring, said verification device (101) is interposed between said one or more of said electronic loop detector devices (40) and said management and control unit (26). 12. Method for verifying one or more electronic loop detector devices (40) or inductance detection units, in which said one or more electronic loop detector devices operate with, or are connected to, sensors based on one or more magnetic coil , the method including a step of generating a simulation signal which simulates a behavior of said one or more magnetic loop and / or reproduces a signal of said one or more magnetic loop, and in which said simulation signal is sent to the electronic device loop detector (40). Method according to claim 12, wherein said one or more electronic loop detector devices (40) are used to acquire traffic information and said one or more magnetic loop is affected by the passage of vehicles on a road. Method according to claim 12 or 13, wherein the simulation signal is based on at least one of the following parameters or combination of parameters: inductance (L), series / parallel resistance and / or series / parallel capacitance. Method according to any one of the preceding claims 12 to 14, wherein the simulation signal is compared with a signal coming from one of said one or more electronic loop detector devices (40). 16. Method according to claim 15, in which a plurality of known magnetic fingerprints are sent to said one or more electronic loop detector devices, and that as many equal or proximate measurements detected by said one or more electronic loop detector devices (40) under tests are compared to said plurality of known magnetic fingerprints. Method according to any one of the preceding claims 12 to 16, in which one of the following operating steps or combinations thereof are carried out: - parameterization step in which the characteristics of said one or more magnetic loops to be simulated are set, such as for example the inductance and / or the dynamics of the signal, in which different values are set for each channel, in order to simulate different magnetic loops; - test and diagnosis phase, in which a self-diagnosis and calibration of a simulation device (101) is carried out, by generating known signals to verify the accuracy of a simulation device; - step of managing references of magnetic traces, in which a library of known magnetic fingerprints is used to set up automatic control tests of said one or more electronic loop detector devices (40); - test library management phase in which test cycles are managed to make a simulation device (101) generate a series of virtual vehicle passages whose number, class, speed and / or length are freely programmed; - verification phase in which, on the basis of a comparison between the simulation signal and the signal detected by said one or more electronic loop detector devices (40), a tolerance of said one or more electronic loop detector devices is estimated ( 40). Method according to any one of claims 11 to 17, wherein the simulation signal is obtained by means of a signal transformer (10), including a primary circuit (12) adapted to be stimulated by means of a current generator (14) , and a secondary circuit (16) provided with an output (17), in which the primary circuit (12) is stimulated by means of a constant current generator (14) to obtain an inductance variation on the secondary circuit (16) for magnetic induction effect. Method according to any one of the preceding claims, in which a plurality of simulation signals are simulated by means of a plurality of variable inductance generators.