WO2007034078A1 - Device for acquiring measurement of walking pressure of persons - Google Patents

Abstract

The invention concerns a device for acquiring measurement of walking pressure of persons on a specific surface to determine presence or passage in a specific physical zone without measuring connectors or connecting cables beneath or in the monitored zone.

Description

 Device for measuring the pressure of steps of people.

The invention relates to a device allowing the acquisition of the measurement of the pressure of steps of persons in order to determine the presence or the passage thereof in a determined physical area and potentially of large area and this without the need for complex and expensive connection of measurement cables or connections inside the controlled physical area. Detecting and determining the presence or passage of people in a specific area are important functions of certain security applications such as those in the airport sector to allow the passage of duly authorized people in sensitive or international areas or still in the technical rooms of banknote distributors. It is essential in these security applications that only the authorized person is present in a specific area when it has been previously identified or authenticated.

The determination of the single passage itself has long been managed by devices known from the prior art such as electromechanical single-pass airlocks, dynamic analysis of the video image, measurement of weight by gauges constraints or even technologies based on photoelectric cells. However, it appeared that these technologies are not suitable for determining the uniqueness of presence in a larger area than that corresponding to the passage of a person.

In the field of determining the uniqueness of the presence and in particular in the problem of verifying the presence of people in sensitive premises and this in order to meet security constraints, it is possible to use several well-known techniques and technologies. of the prior art which are essentially based either on existing technologies on the market for passage detection, or for dynamic analysis of video images.

It was moreover previously defined and proposed by the applicant an electronic and computer device making it possible to solve the problem of the uniqueness of passage and / or presence by using a principle of measurement and dynamic analysis of the pressure of the feet. of a person on the ground using sensors arranged on the ground. It has been demonstrated by the applicant that this technology is more efficient than those using dynamic analysis of video images, weight measurement or detection with photoelectric cells and that this technology makes it possible to offer a level of precision and accuracy of data acquisition compatible with user requests.

However, it appears that it is also necessary to develop specific devices for acquiring pressure information which allow a simplification of the installation over large areas and a reasonable acquisition cost. In fact, in the prior art, there are sensors for acquiring the pressure measurement which are based on the well-known principle of matrix or non-matrix measurement. However, given the state of the art in the field of matrix or non-matrix sensors making it possible to dynamically analyze the presence of steps on the ground, it appears that said sensors have numerous disadvantages. Indeed, the problem to be solved of determining presence on large surfaces implies taking into account a very large number of points to be measured if one wants to have a sufficient definition allowing correct information processing. . For example, the determination of the presence of a person in an area of two meters by two meters or 4 m ² , with a non-matrix measurement sensor with a definition of 2 centimeters per measurement point implies a number of 100 by 100 points to be measured, i.e. 10,000 measurement points which is a quantity of measurement points incompatible with the effective management of real-time information for safety applications. In addition, the connection linked to the transfer of this information requires 20,000 connections, which is a quantity that cannot be exploited on both a technical and economic point.

In fact, matrix pressure sensors are better suited and have great advantages over existing non-matrix sensor techniques. For many years, matrix sensors have been found on the market which are used mainly by design offices, for example in the field of testing car seats for research with an ergonomic purpose or even in the field of odontology. It is, in this type of application, it is necessary to obtain very fine measurement precision. The measurement surface is very small and the implementation of this type of sensors and the acquisition cost are only incidental.

These matrix sensors are made up of flexible printed circuits comprising lines and columns, separated by a substrate made up of either resistive, capacitive or piezoresistive ink. The architecture of the matrix sensors uses lines and columns which has the great advantage of limiting the number of connections to the number of lines plus the number of columns. In the previous example dealing with non-matrix sensors, the number of connections is only 200, or 100 row connections and 100 column connections, which represents 100 times fewer connections than with a non-matrix sensor technology.

These matrix sensors have a significant drawback, however, because of the complexity and manufacturing constraints, their size is limited to relatively small dimensions and not exceeding 1 meter in the largest of the dimensions. This limitation leads to a problem in detecting the presence of natural persons in large areas.

In this case, the dimension of the measurement area requires positioning several sensors side by side, and the connections of the sensors located in the middle must therefore be positioned below the associated sensors. This is a problem for obvious questions of assembly complexity and fragility, the connectors are not designed to support the weight of a person who can walk on it or the passage of a transport cart. On the other hand, said connectors, by their thickness and their rigidity, can damage the sensors located above.

In addition, and in order to cover a large area, the number of connections increases arithmetically since the rows and columns of each sensor must be connected. For example, if you want to cover a square area of 16 square meters using standard sensors of dimensions 50cm X 50cm, each having 25 rows and 25 columns, the area of 4 meters x 4 meters will be covered by 64 sensors, i.e. 3200 connection points (64 X (25 + 25)) which gives 3200 connection cables. This quantity is neither technically nor economically manageable. Finally, these sensors have the drawback, by their design, of being able to be cut only into certain of their dimensions. This imposes technical constraints for their adaptation and integration into particular measurement zones when the dimensions of the zone are not multiples of the dimension of the sensor or when the edges of the zone such as the walls are not parallel. or are not regular. The present invention proposes a new type of device for acquiring the measurement of ground pressures, the aim of which is to solve the aforementioned drawbacks of matrix or non-matrix sensors offering better efficiency, greater simplicity of installation, better discretion for safety applications and finally better robustness, therefore higher reliability.

Said matrix measurement device for ground pressures comprises at least two flexible plastic polymer sheets, comprising rectilinear conductive tracks printed with a layer of conductive ink, constituting lines (2) and columns (3) , and having above and below each of their ends contact zones (4) which can be easily brought into contact, for example and in particular using a flexible conductive adhesive, with another device for acquisition of equivalent and adjacent ground pressure measurement. Said rows (2) and said columns (3) can also be covered on their inner face with a layer of resistive ink, allowing precise measurement of the pressures. Each device can have eight or four connection zones on four or two of its edges. Said device makes it possible to detect a break in the connection cables, in particular by placing the external wires of the connection cable ply directly on the device. The connection orders of the rows and columns of said devices are reversed from one connection area to another, in order to minimize the crossings of tracks, and thereby the number of layers constituting said devices. Connections to said device can also be made by means of flexible printed circuits called flounders (12), comprising on one edge the contact areas necessary for connecting the rows and columns of a device, and on one of their ends a multi-pin connector. . Said devices may also include upper and lower layers of impact protection, made of reinforced rubber of adequate thickness or of any material having suitable characteristics of flexibility and mechanical resistance. Said layers of protective material advantageously can be cut to form a self-locking pattern. Said devices can be cut freely in order to adapt to areas of any shape. Said devices can also be manufactured from strips printed continuously and glued to a sheet of plastic polymer.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the drawings which represents a block diagram illustrating the general structure of a device according to the invention.

- Figure 1 shows a detailed view of the device for acquiring pressure data presence of people in a specific area.

- Figure 2 shows an enlarged summary view of the device allowing the acquisition of the measurement of the pressure of steps of people in a determined area.

- Figure 3 shows an enlarged sectional view of the device allowing the acquisition of the measurement of the pressure of steps of people in a given area.

- Figure 4 shows a sectional view of the assembly of three devices for the acquisition of the measurement of the pressure of steps of people in a specific area. - Figure 5 shows the connection of rows and columns to the connection areas of the device allowing the acquisition of the measurement of the pressure of steps of people in a specific area.

- Figure 6 shows a connection device and its assembly on a device allowing the acquisition of the measurement of the pressure of steps of people in a determined area.

FIG. 7 represents the assembly of six devices allowing the acquisition of the measurement of the pressure of pitch of people in a determined area and of their connection cables located at the periphery of said devices.

- Figure 8 shows an example of self-locking cutting protective sheets of said devices allowing the acquisition of the measurement of the pressure of steps of people in a specific area.

The present invention relates to a device for acquiring the measurement of the pressures exerted on the ground making it possible to detect the presence of people over a large area and having the following characteristics:

- The device for acquiring the measurement of pressures on the ground (1) consists of conductive lines (2) and columns (3), having contact zones (4 above and below each of their ends) ) which can be easily brought into contact with another device for acquiring the pressure measurement on the adjacent ground.

- The dimensions of the device for acquiring the measurement of pressures on the ground are maximum taking into account the production possibilities, but may vary without being limiting between 50cm and 1m for each of the dimensions.

- The device (1) for acquiring the measurement of ground pressures consists of at least two flexible plastic polymer sheets (5), comprising rectilinear conductive tracks printed with a layer of conductive ink and resistive (6), horizontal for one and vertical for the other, and separate. Each sheet of printed plastic polymer is protected by an insulating layer of plastic polymer (7) on the unprinted side of conductive and resistive ink. The devices are further protected from impact and abrasion by a protective layer of reinforced rubber (8) or other equivalent material. - The width of the conductive tracks of the device is variable depending on the measurement accuracy requested and will be, in a preferred embodiment of the invention, 2 centimeters.

- The difference between each track is variable depending on the measurement accuracy requested and will, in a preferred embodiment of the invention, 1 centimeter.

Other more or less spaced geometries can be fabricated to, for example, create specific zones in which the acquisition will be more or less precise.

On the other hand, in a preferred embodiment of the invention, the devices can be prefabricated from printed strips which are juxtaposed and glued to a plastic polymer film. This arrangement makes it possible to produce large acquisition devices. Indeed, if it is complicated to print tracks on large sheets whose dimensions are greater than 1 square meter, it is simple to print strips using a continuous printing technique well known in the state art. The ends of each line (2) protrude on each side of the first and last columns (3) by a length sufficient to ensure reliable connection, this length being fixed, for example, at 1 cm in a preferred embodiment of the invention . These ends will include a rectangular area (4), with dimensions of 2 cm × 1 cm in the preferred embodiment of the invention, devoid of insulating film in order to make the bonding. This rectangular area will always be positioned for the lines above the sensor on the left edge, and below on the right edge. Reverse realization is also possible, as long as all the devices are identically produced. For columns (3), the rectangular area (4) will be positioned above the sensor on the top edge, and below on the bottom edge.

It therefore appears extremely relevant to use devices whose rows (2) and columns (3) can be connected to each other, edge to edge, by a solid and thin means, and preferably by bonding, which avoids the use of connectors. This architecture therefore makes it possible on the one hand to deport the connectors outside the measurement zone and thus the passage of people, and on the other hand to limit as much as possible the total number of connections of the installed system.

It is also very relevant to provide connection devices (10) on the devices, which will only be used for devices located at the edges of the measurement area, that said connection areas (10) are located symmetrically at the four corners of said devices. , on their vertical and horizontal edges. Thus, no constraint will be imposed on the cutting of the devices, and the measurement of the pressure of the weight of people in irregular areas will be greatly facilitated. These connection zones (10) will always include the contacts connected to the lines (2) and the columns (3) of said device. By this embodiment of the invention, the devices (1) can easily be connected two by two, by positioning the rectangular zones (4) one on the other, and maintaining them using a flexible conductive adhesive (9). This connection is not limited in terms of dimensions, and can be carried out both for rows (2) and for columns (3). This assembly method makes it possible to obtain a very large device, without any fragile or dangerous connection for the devices which is placed under the measurement area, and whose number of connections is minimal.

Each line (2) and each column (3) of the device are connected to a particular zone (10) of said device (1), located on one of the edges, and capable of receiving an electrical connector for connection. As described above, in order to facilitate the placement of the devices as much as possible and their adaptation to irregular measurement areas, these connection areas (10) will be repeated at each end of the four edges of the device (1). Each device (1) will therefore have eight possible zones for positioning a connector.

In one possible configuration of the device, the connection areas (10) will be limited to four, since it is easily understood that the devices are reversible.

In a particular embodiment of the device (1), each connection zone (10) will directly contact the two end points corresponding to the columns (3) with the end points corresponding to the lines (2). This arrangement will allow the information processing unit to detect a cable cut.

Indeed, in this way, the current sent on each extreme line (2) (i.e. corresponding to the wire located at the edge of the cable ply) will be directly sent to the corresponding extreme column (3) (this is i.e. corresponding to the wire located on the opposite edge of the cable ply). Thus, while a cable cut cannot be distinguished from an absence of pressure on the sensor (in the absence of pressure, no current sent on the lines (2) is measured back on the columns (3 This embodiment makes it possible to automatically detect such an incident, since normal operation must always correspond to a current measured on these specific columns.

In order to connect each row (2) and each column (3), it is necessary to use flexible multilayer printed circuits. A layer of each circuit will be reserved for the lines (respectively for the columns). At least another layer will be reserved for the connection of each of the rows and each of the columns to the eight connection zones (10). On this layer, the number of crossing tracks (11) will determine the number of these other layers.

In a preferred embodiment of these connection devices (1), the connection orders of the tracks (11) will be successively reversed, in order to minimize the number of crossings of tracks and therefore the number of additional layers as shown in figure 5. In another embodiment of the invention, the devices (1) do not comprise connection zones (10), but ribbon cables made up of flexible printed circuits and which are generally called flounders (12), the so-called flounders are connected to the horizontal or vertical edges of one device (1), in the same way that one device (1) connects to another. Preferably, the dabs will be of sufficient dimensions to interconnect the devices and for example of length 100 centimeters to connect the devices of length 100 cm X 50cm, the width being determined by the dimension necessary for the tracks (11), and having on their longest edge the contact areas (4) necessary for connecting the lines (2) or the columns (3) of a device, and at their end a multi-pin connector (13). The dabs (12) can thus be cut lengthwise and to the appropriate dimension according to the dimension of the area measured. The connectors (13) will allow the sensors to be connected to the acquisition electronics by means of ribbon cables (14). This particular embodiment will make it possible to simplify the architecture of a set of devices (1) as much as possible, and therefore to reduce production costs.

The device (1) being relatively fragile in construction, it should be protected both above against the fall of blunt objects, and below any roughness of irregular ground. This protection will for example be guaranteed by reinforced rubber layers (8) of adequate thickness or by any other material having suitable characteristics of flexibility and mechanical resistance.

It is easily understandable that the devices are manufactured in the factory and directly provided with the two protective layers (8). In this case, the protective layers are bonded over the entire surface of the devices, except on horizontal and vertical strips 2 cm wide, on the 4 edges of said devices, which makes it possible to connect the contact zones (4) of the rows (2) or columns (3) of each of the devices.

In a particular embodiment of the invention, the protective sheets of reinforced rubber (8) are cut into symmetrical trapezoidal slots or any other self-locking assembly, so that the junction of these protective layers (8) between two devices is not straight. This embodiment makes it possible, in the event of progressive sliding of the devices, not to generate a rectilinear hollow space between them, this space being able to prove unfavorable to pressure measurements.

Claims

1. A device for matrix measurement of ground pressures characterized in that said device comprises at least two sheets of flexible plastic polymer, comprising rectilinear conductive tracks printed with a layer of conductive ink, constituting rows (2) and columns (3), and having above and below each of their ends contact zones (4) which can be easily brought into contact, with another device for acquiring the measurement of the equivalent and adjacent ground pressures. 2. Device according to claim 1 characterized in that the contacting of said devices is carried out using a flexible conductive adhesive (9). 3. Device according to claims 1 or 2, characterized in that the lines (2) and the columns (3) are also covered on their inner face with a resistive ink layer, allowing a precise measurement of the pressures. 4. Device according to any one of claims 1 to 3, characterized in that each device comprises eight or four connection zones on four or two of its edges. 5. Device according to any one of claims 1 to 4, characterized in that it makes it possible to detect a cut in the connection cables. 6. Device according to claim 5, characterized in that this detection is permitted by the direct connection on the device of the external wires of the connection cable ply. 7. Device according to claim 4, characterized in that the connection orders of the lines and of the measured columns are reversed from one connection area to the other, in order to minimize the crossings of tracks on the device, and by there the number of layers constituting said device. 8. Device according to any one of claims 1 to 3, characterized in that the connections to said device are made by means of flexible printed circuits called flounders (12), having on one edge the contact areas necessary for connecting the lines and columns of a device, and on one of their ends a multi-pin connector. 9. Device according to any one of the preceding claims, characterized in that it comprises upper and lower layers of impact protection, made of reinforced rubber of adequate thickness or of any material having suitable characteristics of flexibility and mechanical resistance. 10. Device according to claim 9, characterized in that the layers of protective material of said device are cut in order to form a self-locking pattern. 11. Device according to any one of the preceding claims, characterized in that said device can be cut freely in order to adapt to zones of any shape. 12. Device according to any one of the preceding claims, characterized in that said device can be manufactured from strips printed continuously and glued to a sheet of plastic polymer.