EP0552338B1 - Safety system for automatic doors - Google Patents

Abstract

At least one face of one or each leaf of an automatic door has an obstacle detector (20) consisting of a movement detector arranged to generate a signal proportional to the relative movement of an obstacle in the spatial detection field of the detector with respect to the corresponding door leaf. A controller is placed to acquire the detection signal generated by the detector for each door leaf and produce a set point signal for door automation, said set point signal representing the relative movement of the obstacle having the slowest movement with respect to door leaf movement. Each movement detector consists advantageously of a Doppler detector which produces a detection signal having a frequency component porportional to the speed of a surface or obstacle moving relatively to the door leaf.

Description

The present invention relates to an electronic system for optimal protection of persons within the operating range of an automatic door.

State of the art

A system of this kind is intended to ensure the protection of people moving or immobilizing themselves in the space swept by the moving part of an automatic door, for example a revolving door. In order to avoid any contact between the user and the mobile equipment of this kind of automatic door, it is important to equip it with a system for detecting people moving or present in its field of action, in order to to give the automatic control the necessary instructions to avoid contact which could prove to be damaging.

By US-A-4785580 for example, electronic presence detectors are known comprising a transmitter for emitting radiation or waves and a receiver for picking up the reflected diffuse radiation or the waves reflected by an obstacle situated in the covered spatial field to produce a detection signal as a function of the reflected intensity.

These detectors, conventionally installed on the moving part of an automatic revolving door, can monitor the space swept by the door during its movement, and provide a signal when a person or an object is detected. in its radius of action. This signal is by nature an all or nothing signal and, depending on the particular application that one wants to make of it, allows either to slow the movement of the door, or to stop it. The relative speed or the relative distance between the door and the detected obstacle is not taken into account in this.

The unique protective action generated by this type of presence detector can in certain cases hamper the efficient operation of the drum holder, which can then be constantly stopped or slowed down in its rotational movement due to the very irregular passage of pedestrians within its radius of action. All-or-nothing detection is only part of the solution to the protection problem.

On the other hand, it is well known that certain optoelectronic presence detectors are particularly sensitive to the nature, the color and the reflecting power of the background that they cover. During the movement of the door to which it is fixed, this kind of detector sees its useful signal constantly varying, depending on the characteristics of the background; depending on the triggering threshold set, the slightest unforeseen disturbance leads to unwanted detection, and therefore the slowdown or untimely stopping of the door. The more sensitive the detector - which is generally desired so that the protection it provides in front of the moving part of the door extends as close to the ground as possible - the more frequent the appearance of parasitic detection.

A method, based on the analysis of the signal signature as a function of the angular position occupied by the movable part of the door, would make it possible to hold account for the irregular structure of the background. However, an occasional modification would not be taken into account and would cause untimely detection. In addition, this method also does not take into account the relative movement (speed or relative distance) between the door and the obstacle detected.

Finally, other types of presence detectors, based on the measurement of the propagation time of ultrasonic waves, have some of the drawbacks mentioned above, in particular the unwanted detections due to the modification of the sensitivity of the detector as a function of climatic conditions (temperature, humidity), sensitivity to drafts, situation particularly aggravated by the mixing of indoor and outdoor air carried out by the drum carrier during its rotation, sensitivity to vibrations and certain ambient noises. These detectors also provide all or nothing information, controlling either the deceleration or the stopping of the door, without ever taking into account the relative movement between the door and the obstacle detected.

• 1°) Les détecteurs utilisés sont des détecteurs de présence, qui donnent un signal tout ou rien à l'automatisme de commande de la porte de sorte que celle-ci ne peut que ralentir ou s'arrêter et ce indépendamment de la vitesse relative ou de la distance relative entre la porte et l'obstacle. Ce mode d'action sur la porte n'est pas optimal : l'arrêt constitue une nuisance pour les utilisateurs éventuels présents dans les autres secteurs de la porte. Sans doute le ralentissement modère-t-il cette nuisance, mais celle-ci constitue néanmoins un danger pour l'utilisateur éventuellement tombé dans le secteur où la détection a eu lieu. Dans l'un ou l'autre cas, le passage est entravé et le confort d'utilisation de la porte-tambour s'en trouve diminué.
• 2°) Les détecteurs de présence utilisés sont affectés d'imperfections inhérentes à leur technologie, entraînant des détections parasites, ce qui réduit l'efficacité de la porte. Parmi ces imperfections soulignons notamment les suivantes :

In summary, the known detection techniques commonly used to protect people operating in an automatic drum carrier suffer from the following drawbacks:

• 1 °) The detectors used are presence detectors, which give an all or nothing signal to the automatic control of the door so that the latter can only slow down or stop regardless of the relative speed or the relative distance between the door and the obstacle. This mode of action on the door is not optimal: stopping constitutes a nuisance for potential users present in other sectors of the door. No doubt the slowdown moderates this nuisance, but it nonetheless constitutes a danger for the user who may have fallen into the sector where the detection took place. In either case, the passage is obstructed and the comfort of use of the drum holder is reduced.
• 2 °) The presence detectors used are affected by imperfections inherent in their technology, causing parasitic detections, which reduces the efficiency of the door. Among these imperfections, let us highlight the following in particular:

Infrared detectors behave according to the characteristics of the background they cover: nature, color and reflective power; they can be sensitive to external light radiation, and their performance can be reduced due to the permanent passage between the external environment and the internal environment, resulting in differences in brightness.

The ultrasonic detectors have a behavior which is a function of the climatic conditions: temperature, humidity, displacement of air, and their performances can be reduced due to the permanent passage between the external medium and the internal medium, involving variations of these conditions and a permanent air mixing. In addition, these detectors are sensitive to vibrations and certain ambient noises.

Statement of the invention

The present invention aims to remedy the drawbacks mentioned above of known protection systems for automatic doors.

According to a first aspect of the invention, this objective is achieved according to claim 1 by an automatic door provided with a protection system for an automatic door, comprising an obstacle detector fixed on at least one face of each leaf of the door, said obstacle detector comprising a transmitter for emitting radiation or waves in a spatial detection field, a receiver for picking up radiation or reflected waves, and a detection circuit for converting the radiation or reflected waves into a detection signal electric for controlling the automation of the automatic door.

Each obstacle detector is a detector arranged to generate a signal proportional to the relative movement of a surface or an obstacle in the spatial detection field of the detector relative to the corresponding leaf, and the system further comprises a controller arranged to acquire the detection signal generated by the detector of each leaf and produce a setpoint signal for the door automation, said setpoint signal being determined as a function of the relative movement of the obstacle animated by the slowest movement relative to the leaf movement.

Each detector is arranged to produce a detection signal proportional to the relative speed of a surface or an obstacle relative to the corresponding leaf or a detection signal proportional to the distance between an obstacle and the leaf.

Thanks to the setpoint signal which it produces as a function of the relative movement of an obstacle with respect to the door, the controller ensures effective control of the door according to the movement of the user.

The invention can not only be used for a revolving door but also for the protection of persons in front of an automatic pivoting door, generally consisting of a single motorized leaf allowing the door to rotate through an angle practically equal to 90 °.

In the case of a revolving door, the controller makes it possible to adapt the speed of rotation of the door to the movement of the user who moves most slowly in one of its sectors, thus optimizing the operation of the door.

Since this process of slaving the speed of the revolving door is based on a measurement of relative movement in different sectors of the door, it is useful that the detectors operating in the different sectors are adjusted identically.

According to another aspect, the invention proposes according to claim 11 therefore a method for adjusting the detectors controlling a revolving door, according to which a predetermined speed of rotation is communicated to the door, a signal is applied successively to each comparison means of predetermined initial reference, then we do gradually and successively decrease each of said reference signals until a measurement signal is detected by the controller, and then the reference signal of each comparison means which controls the movement is increased by a first identical increment relative to a reference surface, and finally the reference signal of each comparison means which controls the relative movement of an obstacle entering the detection field is increased by a second identical increment, greater than the first increment.

When the detectors fitted to the different leaves are set identically, it is possible to organize the controller so that it compares the detection signals produced by the various detectors on the door and issue an alert signal when the detection signals in the absence of an intruder obstacle (no-load operation) are not all identical or when a predetermined number of them are different from the others. The invention thus advantageously allows automatic self-monitoring of the protection system itself.

The invention is explained in more detail below with the aid of the accompanying drawings.

Brief description of the drawings

• Figure 1 is a schematic plan view of a four-leaf drum holder.
• FIGS. 2A-2D illustrate the different stages of the progression of a pedestrian during his passage through an automatic drum carrier.
• Figures 3 and 4 schematically show an automatic drum holder equipped with a conventional protection device (optoelectronic or ultrasonic presence detector).
• FIG. 5 represents a variant of the device illustrated in FIG. 3.
• FIG. 6 illustrates a mode of detection by ultrasonic or infrared barrier.
• Figures 7 and 8 schematically show an automatic drum holder equipped with a protection device according to the invention.
• FIG. 9 is a block diagram of the protection system according to the invention.
• Figures 10 and 11 show a variant of the device according to the invention, offering better longitudinal coverage.
• Figures 12 and 13 show some waveforms associated with the process of regulating the speed of the drum carrier according to the invention. Figure 14 is a block diagram of the protection system of Figure 10 incorporating an automatic adjustment system according to a second aspect of the invention.

Description of embodiments of the invention

The automatic drum carrier, known per se, represented in FIG. 1, consists for example of four movable leaves, denoted 1, which are integral with a central axis represented in 2. A suitable motorization (not shown) makes it possible to drive the axis 2 and the leaves 1 according to a generally uniform rotational movement represented by the curvilinear arrow. A fixed and curved envelope 3, 3 'partially surrounds the mobile drum, providing access zones 4 and 5.

The assembly as described is generally constructed symmetrically with respect to a wall or a partition 6, 6 ′, conventionally delimiting an exterior zone 7 and an interior zone 8.

It is clear that the number of leaves can be different from four, and that the door can be equipped with a mechanism driving the leaves in a non-circular movement. There are mechanisms driving the leaves partially in rotation and partially in translation.

In FIG. 2, the black square denoted 9 symbolizes a pedestrian wishing to pass for example from the exterior 7 towards the interior 8, who is at the level of the access zone 4 (entrance) and enters it when the space left for example by leaves 1a and 1b is sufficient (Figure 2A). By accompanying the rotational movement of the door (FIG. 2B), it is engaged in the drum holder, between the leaves 1a and 1b. In FIG. 2C, the pedestrian is in view of the access zone 5 (exit) which emerges as a function of the rotation of the door. In Figure 2D, the pedestrian leaves the revolving door by the exit zone 5.

It is understood that, during its progression, a pedestrian who stops or slows down may very well be caught and struck by the leaf which follows it (for example, leaf 1b, FIGS. 2B and 2C). In many cases, this shock between the movable leaf and the pedestrian is harmless: it is enough for the pedestrian to pick up speed and move away from the leaf concerned. However, one can imagine the risk run by a pedestrian who fell to the ground after being struck by a leaf that was still moving. In any case, the comfort of using a automatic revolving door means that the user is never struck by a movable leaf, which amounts to ensuring the safety of people.

In order to avoid any risk of impact between the moving part and the user, or even any accident, the automatic revolving door should be equipped with a detection device capable of giving the automation controlling the door the instructions to avoid this kind of 'accident.

Certain presence detectors are conventionally used for this purpose. Figures 3 and 4 schematically show an automatic four-leaf drum holder 1 equipped with four active infrared presence detectors 10. These are fixed to the upper part of each movable leaf, and comprise, as is well known, a transmitter for emitting infrared radiation from top to bottom, a receiver for picking up reflected diffuse radiation in order to produce a detection signal as a function of the reflected intensity, therefore of the presence or not of an obstacle.

The detection lobe 100 has substantially the shape of a pyramid with a rectangular base, relatively narrow so as not to cover too large a portion of the sector comprised between two consecutive leaves, but wide enough to provide protection in front of the leaf which it protects. . The portion of space covered by the detection lobe does not, however, extend to the ground: it has a dead zone, shown in dotted lines in FIG. 3, zone in which no detection can take place in order to avoid the consideration of background irregularities.

During the rotation of the door and the progression of the pedestrian, a detection takes place as soon as the latter, either for having slowed down, or for having stopped, enters the detection lobe of the sensor. Conventionally, the detection signal produces either the stopping of the door, or its slowing down, regardless of the relative speed or the relative distance between the door and the obstacle detected.

In periods of heavy traffic, several pedestrians may be present simultaneously in the consecutive sectors of the door; stopping the door due to detection in one sector constitutes a nuisance for users present in the other sectors of the door. On the other hand, if detection in one sector causes the door to slow down, this makes it possible to reduce the nuisance for users in other sectors, to the detriment of security in the sector where the detection took place: in fact, if detection occurred following a fall by a user, the simple slowing down of the door can cause a shock between the leaf and the user who fell to the ground.

Although having a dead zone on the ground, the detector can however be influenced by the presence on the ground of objects having a strong contrast in relation to the background; this can lead to parasitic detections, and therefore to a reduction in the efficiency of the system.

The protection mode illustrated in Figure 3 is subject to a few variants characterized by different lobe shapes, a different sensor position (horizontally at any point on the upper part of the door, or even vertically or obliquely, on the central axis or the opposite upright or even halfway up). A similar protection mode, based on ultrasonic detection is also possible. It usually involves a conically shaped lobe, the diameter of the circular base of which is generally reduced. In all these cases, presence detection involves a simple action on the movement of the door: slowing down or stopping, with the drawbacks mentioned above. It is clear that this completely usual mode of protection does not allow the relative movement between the door and the obstacle to be taken into account.

FIG. 5 illustrates another detection method conventionally used. This consists, by leaf, of a longitudinal detector fixed horizontally halfway up the leaf. FIG. 5 shows for example the detector of leaf 1. The detection can be infrared or ultrasonic: the detection lobe 100 is horizontal or almost horizontal, and extends in a space very close to the door. It is in fact a somewhat particular variant of the cases cited above, which has the advantage of better immunity to parasitic detections due to ground irregularities because the detection lobe is not directed towards floor. However, in the infrared version, the detector can be affected by external parasitic light radiation, while in the ultrasonic version, many of the disadvantages mentioned affect the detector. On the other hand, the covered area is quite small, and children or fallen people cannot be detected. This detection mode, in this case also, provides information all or nothing, causing only a single action on the door, without taking into account its relative movement.

In FIG. 6 we can see another conventional variant in which an ultrasonic or infrared beam, coming from a detector 10 placed in the lower part of the axis of rotation 2, horizontally covers a field in front of the lower part of the leaf from the 'axis of rotation 2 to substantially the opposite edge of the leaf, thus constituting a barrier almost at ground level. As soon as the barrier is intercepted by a person during the rotation of the door and this regardless of the relative speed or the relative distance between the door and the obstacle, an all or nothing signal is given and the door slows down or s 'stopped. Some of the drawbacks mentioned in the foregoing and inherent in the technology used (infrared or ultrasonic) also affect the system. It is clear that the drawings illustrate only one of the detectors, and that other similar detectors are fitted to the other leaves of the door.

The invention provides a solution to the problems stated above. Figures 7 and 8 schematically show a drum holder equipped with a protection system according to the invention, in a preferred embodiment. The protection system includes a leaf detector. In FIG. 7 we see only one detector 20 fixed for example to the upper part of the leaf 1 and directing its detection lobe 200 from top to bottom. According to the invention, the detectors 20 are detectors capable of measuring the relative speed or the relative distance between a being or object appearing in their field of action and the door. Detectors are for example Doppler detectors (known per se), based on microwave technology but other technologies are applicable, such as for example ultrasound.

The system also includes a controller for acquiring the signals supplied by the detectors fitted to the revolving door, calculating the servo setpoint of the latter and optionally ensuring self-monitoring of the system. The controller is shown in Figure 9 which is a block diagram of the complete protection system according to the invention.

As is known per se, each detector comprises a transmitter circuit 12 for generating a microwave signal which is radiated in space by an antenna shown at 11. This, as is well known, can be constituted a horn, a parabola, a radiating waveguide or any other radiating element known to those skilled in the art. Any relative moving obstacle in the field of action of the detector in a sector of the door reflects part of the incident wave and the reflected wave is picked up by the antenna and mixed with the incident wave thanks to a mixer present. in a receiver circuit 13. Consequently, and due to the Doppler effect, a low frequency signal is available at the output of the receiver 13. The frequency of the Doppler signal is proportional to the relative speed of the detected obstacle and its amplitude is proportional to the size and proximity of the detected obstacle.

The detection signal from each receiver 13 is applied to an amplification and filtering circuit 14 the output of which is for example connected to the inputs of a digitization cell 15. The latter mainly comprises two comparators, known per se, which exploit the information contained in the amplitude of the detection signal.

The first comparator 15a has a comparison threshold denoted + fixed for detecting the low amplitude signal corresponding to the relative movement of the ground relative to the detector fixed on the leaf. At the output of comparator 15a, a digitized square wave signal appears, as shown in 160.

When a person or an object of sufficient mass comes before the detector and is animated relative to the latter by a relative speed, it generates a Doppler signal of amplitude significantly greater than the signal coming from the reflected wave. because of its size and proximity.

The second comparator 15b has a comparison threshold denoted + fixed to detect a signal of greater amplitude than the first comparator: it therefore switches only when a person or an object has been detected. At the output of the comparator 15b, a digitized square wave signal appears, as shown in 170, only during the periods of detection of a person or an object.

As can be seen, each of the detectors 20 delivers at its output two digital signals containing information of a frequency nature which, for one of the signals, is proportional to the relative speed of travel of the ground relative to the detector (leaf) in the absence of detection of an obstacle, and for the other, at the relative speed of the obstacle with respect to the detector 20 (leaf).

Before going further in the description of the other characteristics of the system according to the invention, it should be noted that a motion detector as provided in accordance with the invention is not affected by the drawbacks mentioned in the description of the solutions. classics: they are not influenced by the structure of the background they cover (nature, color and to some extent reflective power) they are not sensitive to light radiation or to differences in brightness between the outdoor areas and interior of the revolving door, and they do not behave affected by the climatic conditions mentioned above, neither by air currents nor by ambient noise.

It should also be noted that the detectors used can occupy any position on each leaf of the drum carrier, provided that this location allows them to measure the relative speed of the obstacles to be detected.

It should also be noted that an advantageous variant of the invention would be to equip the detectors with an antenna formed by a radiating waveguide, known per se, which would make it possible to provide longitudinal coverage over the entire width of the leaf, as shown in Figures 10 and 11.

Unlike the embodiment illustrated in FIGS. 7 and 8 where the detectors radiate in a conical-shaped detection lobe with an elliptical base, the detectors represented in FIG. 10 radiate in a detection lobe 200 having the shape of a narrow brush extending over the entire width of the detector (FIG. 11). This variant advantageously reinforces the efficiency of detection.

• calcul d'une consigne de vitesse à transmettre à la commande du moteur de la porte;
• réglage automatique du système;
• autosurveillance du système.

The signals 160 and 170 from each detector 20 are routed by the lines 16 and 17 to the controller 30. The latter consists for example of a circuit structured around a microprocessor which comprises the conventional elements or peripherals. Appropriate software allows the controller to perform the following functions:

• calculation of a speed setpoint to be transmitted to the door motor control;
• automatic system adjustment;
• self-monitoring of the system.

In order to optimize the functioning of the revolving door, it is advantageous to regulate the speed of rotation thereof as a function of the obstacles appearing in front of the leaves, while authorizing the stopping of the door when a dangerous situation arises.

• il procède périodiquement à l'acquisition des signaux d'entrée 160 donnant la vitesse de la porte en l'absence d'utilisateur et stocke cette valeur en mémoire;
• il scrute en permanence les signaux 170 donnant la vitesse relative entre un utilisateur détecté et la porte;
• il détecte l'apparition d'une fréquence Doppler dans l'un des signaux 170, ce qui signifie qu'un utilisateur est entré dans le lobe de détection de l'un des détecteurs, donc qu'il est animé d'une vitesse relative tendant à le faire entrer en contact avec le vantail qui le suit;
• il calcule la consigne de vitesse à communiquer à la commande de la porte pour faire tendre vers zéro la fréquence Doppler mesurée sur celui des signaux 170 où le risque de collision est le plus important.

According to the invention, the controller 30 performs several tasks:

• it periodically acquires the input signals 160 giving the speed of the door in the absence of a user and stores this value in memory;
• it continuously scans the signals 170 giving the relative speed between a detected user and the door;
• it detects the appearance of a Doppler frequency in one of the signals 170, which means that a user has entered the detection lobe of one of the detectors, therefore that he is driven by a relative speed tending to bring him into contact with the leaf which the following;
• it calculates the speed setpoint to be communicated to the door control so that the Doppler frequency measured on that of the signals 170 where the risk of collision is greatest is brought to zero.

The speed setpoint is communicated to the door control by means of a connection shown in 19 which can be of any type: for example analog, serial, parallel, or any other known means of communication.

A regulation circuit at the door control level can act on the speed of the motor, according to the setpoint calculated by the controller 30, in order to restore satisfactory conditions of use, namely a rotation speed adapted to the slowest of the users present in the drum holder at a determined time.

When, following the slowdown of the door, the relative speed measured at the detector tends towards zero, this means either that the slowest user is moving in synchronism with the door, or that he has picked up speed and is out of the detector detection lobe attached to the leaf preceding it. This situation is obviously harmless to the user.

On the other hand, when the door slowdown instruction does not give the expected result, namely the cancellation of the relative speed measured by the detector, this means that the detected obstacle is fixed or that it is moving in the opposite direction to the rotation of the door. In this case, the controller must order the immediate stop of the door in order to prevent the obstacle from coming into contact with the leaf.

The regulation process can be continuous or discontinuous. Figures 12 and 13 show some waveforms illustrating a discontinuous regulation process according to the invention and which constitutes one example of application among others possible. The waveform denoted Vrel corresponds to the relative speed between the detected obstacle and the leaf, calculated by the microprocessor of the controller 30, from one of the frequency channels 170. The waveform denoted CF is for example a discontinuous braking setpoint, active in the high state noted 1. The waveform noted V represents the speed of the door. All these curves are referenced with respect to the same time axis.

FIG. 12 illustrates the case where a user has a movement speed slightly lower than the tangential speed of the door. It can be seen that from the instant t0, the relative speed is detected on one of the measurement channels as soon as the user enters the detection lobe of the leaf which precedes it. At the instant t1, the controller 30 sends a braking instruction CF to the automatic control of the door. This automatism begins to act at time t1 + ε, which results in a reduction in the speed V of the door, and in the case envisaged here, in a reduction in the measured relative speed Vrel. In the example illustrated, the duration of braking is for example 100 milliseconds. The brake setpoint CF returns to the low state at time t2. During the following time interval t2-t3, which for example has a duration of 100 milliseconds, the controller proceeds to acquire the relative speed and if this is not zero, it sends a second time a brake setpoint at the door control automation. The setpoint is in the high state during the time interval t3-t4 of 100 milliseconds for example. From time t3 + ε, the braking effect is such that the speed V of the door decreases again and, in the case considered, the relative speed measured Vrel also decreases. The process described above is repeated, for example once again. At time t6, ie 500 milliseconds after the start of the regulation phase, the controller finds that the relative speed Vrel has been canceled, either because the user is moving in synchronism with the door, or because he is now outside the detection lobe. The door speed is maintained at its new value for 500 milliseconds for example, after which the controller can restore the door to its initial speed.

FIG. 13 illustrates the case where a user is stopped in a sector of the revolving door. The process proceeds as described above. However, at time t6 (for example 500 milliseconds after the start of the regulation process) the controller notices that the relative speed of the detected obstacle compared to the leaf is far from being canceled, and he then orders the stop immediately from the door.

It should be noted that the obstacle stopped leads to a relative speed measurement equal to the relative speed of travel of the ground relative to the leaf, which can be used by the controller 30.

It is easy to see that the use of Doppler detectors fitted with a direction of travel discriminator makes it possible to detect whether the obstacle is moving in the direction of rotation of the door or in the opposite direction, which allows further regulation. finer than the process described above.

It is clear that other types of detectors can be used, for example infrared or ultrasonic detectors, but with the drawbacks inherent in their technology as explained above.

In the particular case where the detector is placed horizontally halfway up the leaf or on the lower cross member of the leaf, or even vertically in the lower part of the leaf, it is possible to use a distance measuring detector (for example ultrasonic) which transmits and receives in a horizontal plane or in a vertical plane, and which calculates the propagation time between the emitted wave and the reflected wave, which, as is well known, amounts to measuring the relative distance between the detector (therefore the leaf) and the obstacle located in front of the leaf.

The speed setpoint calculated by the controller 30 and communicated to the automatic control of the revolving door must allow the regulation process to maintain between the obstacle and the door a distance greater than a given value.

Other types of detectors can be used for distance measurement as described, and in particular infrared triangulation detectors.

It is also obvious that the distance measurement is inapplicable when the detector is fixed to the upper part of the leaf and directs its detection lobe towards the ground with an angle of inclination relative to the vertical. In this case, the distance measured also depends on the size of the obstacle detected, and not only on its position relative to the door, which is not the case when the measurement is made in a horizontal plane.

As can be seen, the regulation process according to the invention makes it possible, thanks to the speed setpoint calculated by the controller 30, to adapt the speed of the drum carrier to the user who moves most slowly in one of its sectors and thus optimize their operation.

The device according to the invention is a fortiori capable of controlling only the stopping of the door or its slowing down to a predetermined speed just as in conventional known systems.

On the other hand, the invention can advantageously be used for the protection of persons in front of an automatic pivoting door, generally consisting of a single motorized leaf allowing the door to rotate through an angle practically equal to 90 °. This embodiment can be considered as a particular case of application of the invention, although the control of the pivoting door is not necessary in this case.

Another aspect of the invention relates to the automatic adjustment of the detectors. Since the whole process of regulating the speed of the revolving door is based on the measurement of the relative speed in different sectors of the door, it is advantageous that the detectors monitoring the different sectors of the door are adjusted identically. As each detector, as described above, provides two measurement signals, the adjustment of the detectors fitted to an automatic drum holder represents tedious work, but also particularly delicate. It is certain that the installers do not necessarily have the means to control the quality of the adjustment on site, or even the skills required to do so. The invention allows, although this is not an absolute necessity, an automatic adjustment process of the detectors fitted to a drum holder. We will understand its operation by referring to Figure 14. After installation and connection of the detectors, the installer puts the revolving door in service and starts the initial adjustment phase by pushing, for example, on a push button acting on an input line 31 of the microprocessor. The door is driven in a uniform rotational movement, at a speed predetermined by use.

During this rotation, the controller 30 proceeds to the successive acquisition of the signals 160, 170 by acting progressively on the reference voltage of each of the comparators 15a and 15b. To this end, the reference voltage of the comparators 15a and 15b is supplied by the controller 30 by analog outputs 32, 33 coming from digital / analog converters (DAC).

The process starts from an initial setting for which the reference voltage of the comparators 15a and 15b is for example maximum and for which no frequency can be detected on the signals 160 and 170 given the large switching threshold initially imposed on the comparators and the low amplitude of the Doppler signal corresponding to the relative speed of travel of the ground with respect to the respective leaves. The controller 30 progressively and successively decreases the reference voltage applied to the comparators 15a and 15b until a Doppler frequency is detected on each signal 160, 170. The controller 30 then increases the reference voltage by a small identical increment comparators 15a which give the relative speed of travel of the ground or of a reference surface with respect to the leaves, in order to take account of any drifts and to provide a tolerance in the measurement of this relative speed. It then proceeds to the same operation for the other comparators 15b which give the relative speed of the detected obstacle relative to the leaves, but with a larger identical increment, fixed by experience. At the end of this adjustment sequence, each of the detectors is adjusted identically, a condition necessary for optimal operation.

Other methods of adjusting the detectors are possible, for example automatic adjustment of the gain of each of the amplifiers 14 while the reference voltages of the comparators 15a and 15b are fixed at a precise value determined beforehand. This adjustment process involves changing the values of the amplifier's feedback resistances, which can be accomplished by switching a set of resistors by means of analog switches controlled by the microprocessor via output lines. It is obvious that an automatic detector adjustment process can, according to the invention, be applied to other types of detectors.

A final possibility concerns the self-monitoring of the system. As the protection system has to stop the drum holder in the event of danger, it is sometimes essential, for safety reasons, to use self-monitoring detectors in its environment. As the detectors fitted to the leaves of an automatic revolving door can be adjusted identically, it is simple to apply the majority rule to them in order to determine whether their operation is correct. Indeed, the rotation of the drum holder is generally controlled by approach detectors located on either side of the accesses 4 and 5 when a user comes up to them. It is easily understood that, during the no load rotation of the door, the controller 30 can check whether the speeds given by each of the detection signals 160 are identical. Otherwise, it means that one or more detectors have failed, which should be reported immediately. It goes without saying that the software residing in the controller 30 must be written in compliance with the standards concerning self-monitoring systems controlled by microprocessor. It is also clear that the self-monitoring as described above can be applied to any type of detector usable in a protection system for an automatic drum carrier.

Finally, the block diagrams of Figures 9 and 14 are given by way of example. Some internal functions detectors can be perfectly performed within the controller 30 itself, in particular all the functions related to comparators 15a and 15b which can be provided in digital technology, by means of the direct connection of the output of the filter amplifiers to the inputs of analog converters / digital to be provided on board the controller. In this case, the automatic adjustment function no longer requires digital / analog converters at the output, since the whole process described above can be carried out entirely by software.

Other modes of processing the Doppler signal, previously amplified and made available at the inputs of each analog / digital converter of the controller 30, are possible and do not necessarily imply the digitization of this Doppler signal using two comparators 15a and 15b, as described above, or their software equivalent.

We are thinking in particular of the digital processing of the Doppler signal, aiming at the calculation of the frequency and the amplitude thereof, using an algorithm known per se, and at the comparison of these calculated values with previously stored references, said references corresponding to typical system operations: unladen, in the presence of an obstacle, etc.

The recognition of an obstacle and the calculation of its relative speed could advantageously be carried out according to the variant consisting in comparing temporal samples of the detection signal with previously stored reference models, said reference models corresponding to typical operations. of the system: no-load operation, operation in the presence of an obstacle, etc. All signal shape recognition techniques can be applied, including fuzzy logic techniques.

Claims (11)

1. Automatic door provided with a protection system including an obstacle detector (20) fixed to at least one face of each leaf of the door, the said obstacle detector (20) comprising a transmitter (12) for transmitting radiation or waves in a spatial detection field, a receiver (13) for sensing the reflected radiation or waves, and a detection circuit for converting the reflected radiation or waves into an electrical detection signal serving to control the automatic control mechanism of the automatic door, characterised in that each obstacle detector (20) is a detector arranged to generate a signal proportional to the relative speed or to the relative distance of a surface or obstacle in the spatial detection field of the detector with respect to the corresponding leaf, and in that the protection system also comprises a controller (30) arranged to acquire the detection signal generated by the detector (20) of each leaf and produce a speed information signal for the automatic control mechanism of the door, the said speed information signal being determined according to the relative speed or relative variation in distance of the obstacle with the slowest movement with respect to the movement of the leaves so as to regulate the speed of the leaves of the door in order to prevent any contact between one of the leaves and the slowest obstacle.
2. Door according to Claim 1, characterised in that each detector (20) produces a spatial detection field directed from top to bottom with an angle of inclination with respect to the vertical so as to produce a detection signal proportional to the relative speed of a reference surface or of an obstacle with respect to the corresponding leaf.
3. Door according to Claim 2, characterised in that each detector (20) consists of a Doppler effect detector which produces a detection signal including a frequency component proportional to the speed of a reference surface or of an obstacle having a relative movement with respect to the leaf.
4. Door according to Claim 1, characterised in that each detector (20) directs a spatial detection field horizontally and produces a detection signal proportional to the distance between an obstacle and the leaf.
5. Door according to any one of the preceding claims, characterised in that each detector comprises comparison means (15) arranged to receive and compare each detection signal with a reference signal and to produce a signal proportional to the difference between the two input signals.
6. Door according to Claim 5, characterised in that the comparison means (15) are arranged to compare each detection signal with several reference signals and to produce several signals, each of them being proportional to the difference between a detection signal and each of the reference signals.
7. Door according to Claim 5 or 6, characterised in that the aforementioned comparison means (15) are produced in the detection circuit of each detector (20).
8. Door according to Claim 5 or 6, characterised in that the aforementioned comparison means are produced within the controller (30).
9. Door according to any one of Claims 5 to 8, characterised in that the reference signals are adjusted on the basis of information sent by the controller (30).
10. Door according to any one of the preceding claims, characterised in that the controller (30) is organised so as to compare the detection signals produced by the different detectors (20) on the door and emit a warning signal when the detection signals, in the absence of an intruding obstacle (operation off-load), are not all identical or when a predetermined number amongst them are different from the others.
11. Method of regulating the detectors controlling a revolving door, each detector (20) being disposed so as to direct its spatial detection field from top to bottom with an angle of inclination with respect to the vertical, and each detector having a first comparison means (15a) and a second comparison means (15b), the method being characterised by the following steps:

    (a) a predetermined rotation speed is communicated to the door,

    (b) an initial reference signal is applied to the said comparison means (15a, 15b) of each detector,

    (c) the aforementioned initial reference signal is reduced progressively and successively on the first comparison means (15a) and on the second comparison means (15b) until a measurement signal (160, 170) appears at the respective outputs of the said comparison means,

    (d) the reference signal applied to each first comparison means (15a) is then increased by a first predetermined increment,

    (e) the reference signal applied to each second comparison means (15b) is increased by a second predetermined increment, greater than the aforementioned first increment.

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