Method for controlling a winding actuator, winding actuator configured for such a method, and closure or sun-shading apparatus including such an actuator

The disclosed method enables control of an actuator for winding a blackout screen around a winding shaft. The actuator includes at least one electric motor. The method includes: at least one step that involves using an electronic unit to detect screen locking, during lowering or raising, by detecting a torque exerted by the motor on the winding shaft, the torque being determined on the basis of a current for supplying power to the motor; and a step that involves stopping the motor when a signal representing the detected current is greater than a threshold value. The electronic unit is parametrizable. Moreover, the method includes at least one additional step, used when the signal representing the detected current is less than the threshold value and involving detecting, on the basis of the detected current, a localized change in the shape of the screen, during lowering, by using the same electronic unit.

The invention relates to a method for controlling a winding actuator of a blackout screen around a shaft. The invention also relates to a winding actuator for such a screen, this actuator being configured to carry out such a method. Lastly, the invention relates to a closure or sun-shading installation comprising such an actuator.

In the field of closure or sun-shading devices, it is known to maneuver a blackout screen for an opening between an open configuration, in which it is wound around a winding shaft, generally inside a box located above the opening, and a closed position where it extends vertically in the opening, below the winding shaft. In this type of device, it is known to detect an obstacle that opposes the lowering of the screen, i.e., its movement from its first configuration to its second configuration, by detecting a torque supplied by an electric motor belonging to the actuator, owing to the monitoring of a power supply current of this motor. According to a so-called stop detection function, it is known to equip a winding actuator for a rolling shutter of a device that reacts when the screen is blocked on an obstacle, to the point that it is compressed by the motor, which must exert an additional torque, this torque being detected by the device in question.

It is desirable to be able to anticipate such a blocking situation by reacting in advance, once the screen encounters an obstacle, and before it blocks the rotation of the winding shaft driven by the actuator. To that end, it is possible to equip the head of an actuator with an accelerometer or to use an obstacle generating device, as known from EP-A-2 746 526. Other electromechanical devices used for this purpose are based on relative movements between certain component parts of the actuator or the use of force sensors or contactors. These mechanical or mechatronic solutions are precise, but have the drawback of making the configuration more complex, or even impossible, based on the installation in which the actuator must be integrated. Thus, it is not possible to take into account the weight or size of the screen, the diameter of the winding shaft, or the usage conditions on the implementation site of the installation. However, these usage conditions, in particular the quality of the slides guiding the screen, which can be clean and correctly mounted in a new building or have hard spots and alignment defects as part of a renovation, may have a major influence on the movement possibilities of the screen. In the known electromechanical or mechanical materials, the adaptations to the usage conditions are therefore limited and it is only possible to take actual usage conditions of the actuator into account with difficulty. Furthermore, poor adaptation to the usage conditions causes risks of untimely stops of the movement of the shutter, which are bothersome in the use of the shutter on a daily basis.

Furthermore, a certain number of actuators are equipped with a spring-operated brake that has the advantage of effectively accompanying the movements of the winding shaft, when the latter is driving relative to the screen. However, the use of such a spring-operated brake conceals the torque generated by the weight of the screen upon lowering, which limits the performance of a technical solution based solely on measuring the torque delivered by the motor of the actuator.

The invention more particularly aims to resolve these drawbacks by proposing a new method for controlling an actuator for winding a blackout screen that makes it possible to take into account actual usage conditions of the actuator, with a particularly attractive cost, and which is not hindered by the use of a brake, in particular of the spring-operated or cam-operated type.

To that end, the invention relates to a method for controlling an actuator for winding a blackout screen around a winding shaft, this actuator comprising at least one electric motor, the method including at least steps a1 and a2 consisting on the one hand of using electronic means to detect blocking of the screen, during the lowering or raising, by detecting a torque exerted by the motor on the winding shaft, this torque being determined on the basis of a current detected for supplying power to the motor, and on the other hand of stopping the motor when a signal representing the detected current is greater than a threshold current value. According to the invention, the electronic means are parameterizable, and this method comprises an additional step b, implemented when the signal representative of the detected current is below the threshold current value, consisting of detecting a localized deformation of the screen, during lowering, by using the same electronic means and based on the detected current.

Owing to the invention, the early detection of an obstacle obtained in step b resolves the same issues as the mechanical or mechatronic solutions of the prior art, while having the flexibility of a software solution. Step b supplements steps a1, a2 and allows a finer detection, before the motor of the actuator exerts force, via the screen, on stops or any obstacles. Since the electronic means used in step b are parameterizable, the detection level used in this step can be adjusted based on actual usage conditions of the actuator in a closure or sun-shading installation, in particular taking into account the size and weight of the screen, the diameter of the winding shaft and the environment of the actuator, in particular, the quality of the slides guiding the screen.

According to advantageous but optional aspects of the invention, such a method may incorporate one or more of the following features, considered in any technically allowable combination:Step b comprises at least elementary steps b1 to b4 consisting of:b1) creating a first digital signal, by applying first digital processing to a signal representative of the power supply current of the motor,b2) creating a second digital signal by applying at least one second digital processing operation to the first digital signal,b3) comparing the first digital signal to the second digital signal,b4) establishing whether blocking of the screen is imminent, based on the result of the comparison of elementary step b3.The second digital signal is created by applying value shift processing to the first digital signal, in addition to the second digital processing operation.The first digital processing operation and the second digital processing operation are of the same nature.The first digital processing operation and/or the second digital processing operation comprise the application of a low-pass filter.The signal representative of the current is an image of an instantaneous value of this current and, during elementary step b4, blocking of the screen is considered to be imminent when the first digital signal is greater than the second digital signal.The signal representative of the current is an image of an instantaneous value of this current and, during elementary step b4, blocking of the screen is considered to be imminent when the difference between the first digital signal and the second digital signal is above a predefined threshold.The method comprises a prior step c for parameterizing the electronic means, based on a determined sensitivity level, in particular selected, for detecting the imminent blocking of the screen and/or the ambient temperature of the actuator.The parameterization of the electronic means used for step b is independent of the adjustment used for steps a1 and a2.

The invention also relates to an actuator for winding a blackout screen around a winding shaft, this actuator comprising at least one electric motor and electronic control means for this motor. According to the invention, these electronic control means are configured to carry out the aforementioned method.

Advantageously, the motor is a synchronous permanent magnet motor.

Lastly, the invention relates to a closure or sun-shading installation incorporating, inter alia, an actuator as described above.

FIGS. 4 and 5must be considered to simulate the operation of the actuator because they do not take into account the stopping of the actuator that may occur after carrying out step b, as shown by the explanations that follow.

The installation2shown inFIG. 1comprises a screen or apron4formed by several slats6articulated relative to one another and that comprise a lower slat62, intended to bear against the threshold of an opening O closed off by the screen4in the lower position, as well as an upper slat64attached to a winding shaft8using two articulations or connecting elements10, these connecting elements being able to be rigid or flexible.

The screen4is made up of slats6fastened to one another so as to have a space between them when the screen4is in a suspended position, i.e., when the screen4is not in the lower stop position where all of the slats6are stacked against one another so as to be joined.

The winding shaft8is mounted inside a box12, with the possibility of rotation around an axis X2, which is horizontal and stationary, and which constitutes a central axis for the installation2.

The winding shaft8is rotated around the axis X2using a tubular actuator100, more particularly visible inFIG. 2, in which the screen4is shown in a partially raised position, i.e., partially wound around the winding shaft8. The actuator100comprises a fixed cylindrical tube101in which a gear motor102is mounted that comprises a synchronous permanent magnet electric motor103, in the example a brushless electronic switching motor, as well as a spring-operated brake104and a reduction gear105. Reference106denotes the output shaft of the reduction gear105, which protrudes at one end101A of the fixed tube101and drives a wheel200secured in rotation with the tube of the winding shaft8.

The winding shaft8rotates around the axis X2and the fixed tube101owing to two pivot links, one of which is provided by a bearing ring210mounted near the end101B of the fixed tube101opposite the end101A. The second pivot link, which is not visible in the figures, is installed at the other end of the winding shaft8.

The actuator100also comprises a fastening part or head108, protruding at the end101B of the tube101and making it possible to fasten the actuator100on a side wall of the box12. This fastening part108also closes off the tube101and supports an electronic unit109for controlling the power supply of the motor103. The electronic unit109is supplied with alternating voltage by a power cable220and housed in the tube101. The electronic unit109also comprises a unit, not shown, for controlling the sequential power supply of the windings of the motor103that rectifies the power supply voltage of the motor, using a diode bridge, filters this voltage, using a capacitance, and sequentially powers each winding, using a module made up of switches.

The electronic unit109is provided to be in communication with a centralized controller30or a remote control32. A movement control order supplied by the centralized controller30or the remote control32causes a power supply of the motor103making it rotate the winding shaft8, in one direction or the other, around the axis X2, based on the user's choices. A current I circulates in an electrical conductor107that connects the electronic unit109to the motor103and is sequentially supplied to the different windings of the motor103.

The installation2also comprises two slides14that extend on either side of the opening O, below the box12, and in which the ends of the slats6are respectively engaged.

A device1092for monitoring torque, based on the stop detection function, is integrated into the electronic unit109and works based on the monitoring of the current I supplied to the motor103by the electronic unit109. This current I is direct and developed from the alternating voltage delivered by the power cable220. Thus, the electronic unit109comprises an AC/DC converter1094. For the clarity of the drawing, the electrical connections within the electronic unit109are not shown inFIG. 2. This stop detection function is carried out in a first step of the method according to the invention and suitable for detecting a fast and abrupt change in the torque when, after the screen4reaches a stop, the screen4is unwound until it is constrained by the latter, thereby creating an increase in torque at the motor103.

In practice, the device1092comprises a microprocessor1092A and a memory1092B. In practice, the memory1092B is preferably integrated into the microprocessor1092A. The device1092also comprises an RC circuit1092C that comprises a shunting resistance through which the power supply current I of the motor103is measured, this shunting resistance being electrically connected to a power supply module of this motor103and a mass that is at a reference voltage. The current I is thus sometimes called “shunting current”.

The method, shown diagrammatically inFIG. 3, comprises a first elementary step500during which the power supply current I of the motor103is acquired by the electronic unit109. This current I constitutes an image of the torque C103delivered by the motor103to the elements104,105and200, and through them, to the winding shaft8.

In practice, the value of the current I is provided to the microprocessor1092A in the form of an analog signal representative of the value of the current I at each moment. During step500, this analog signal is converted by the microprocessor1092A into a digital signal S(I).

In a second elementary step502, the value of the digital signal S(I) is compared to a reference value Iref. The elementary steps500and502together constitute a first step a1 of the method according to the invention.

The case is considered where the actuator100must unwind the screen4, i.e., drive the winding shaft108in a rotation direction around the axis X2that corresponds to a lowering of the screen4, where the lower slat62is moved toward the threshold of the opening O. The screen4normally constitutes a driving load during this lowering, inasmuch as its weight tends to rotate the winding shaft8in the desired rotation direction. In this case, the current I measured by the electronic unit109has a substantially constant value that is related to the intrinsic characteristics of the motor103, as well as those of the spring-operated brake104, the reducing gear105and the diameter of the winding shaft8. This value is denoted I0inFIG. 4.

The current I, measured in the first elementary step500using the electronic unit109, is representative of the withholding torque C103exerted by the motor103on the winding shaft8.

When the screen4encounters an obstacle, either inside one of the slides14or on the trajectory of the lower slat62between the slides14, the slats6come closer together and settle on one another, then the screen4deforms locally in the box12; the screen4is next compressed between the lower slat62blocked on the obstacle or the end of travel stop and the uppermost slat6, which is not part of the portion of the apron4wound around the winding shaft8.

In other words, when the lower slat62of the screen4abuts either on the lower end of travel or on an obstacle, the following slat6continues to lower until it abuts against the lower slat62, and so forth up to a following slat6, which may be the upper slat64fastened to the winding shaft8. In this way, the screen4gradually becomes rigid starting from the lower slat62up to the winding shaft8.

The screen4thus becomes a load to be driven for the actuator100and the torque to be exerted to continue to move the lower slat62, or tend to move it over the lowering travel, becomes variable, then increases considerably, to the point that the value of the current I exceeds the reference value Iref.

Thus, during the second elementary step502of step a1, it is verified whether the value of the signal S(I) is greater than the value Iref. If this is the case, the method detects blocking of the screen4during its lowering and an additional step504is carried out, during which an audio or visual alarm is activated, while optionally, the actuator100is supplied with current to perform a reverse travel, raising the screen4, with a limited amplitude in order to ease the vertical stress on the screen4and on the obstacle on which the lower slat62is bearing, before stopping the motor103. Otherwise, i.e., if the value of the digital signal S(I) remains lower than the value Iref, the first elementary step500is carried out again, at the predetermined measuring frequency, i.e., 5 ms in the example.

The elementary step504constitutes a second step a2 of the method according to the invention that is carried out after step a1. Steps a1 and a2 are carried out to perform the stop detection function.

The case is considered where the actuator100must wind the screen4, i.e., drive the winding shaft108in a rotation direction around the axis X2that corresponds to a raising of the screen4. In this case, if the screen4becomes jammed in one of the slides14, the torque to be exerted to continue to move it, or tend to move it, over the raising travel, increases considerably, to the point that the value of the current I exceeds the reference value Iref. Thus, steps a1 and a2 can also be carried out over the raising of the screen4.

Alternatively, the threshold values Iref used for the lowering and raising are different.

This stop detection function, during lowering or raising, may be deactivated or modified, based on usage conditions of the installation2and as shown by the following explanations.

FIG. 4shows the case where, during the lowering of the screen4, the latter encounters an obstacle after approximately 3 seconds after beginning its lowering movement, in practice 3.25 s as shown with point P inFIGS. 4 and 5, the screen4continues to unwind, then blocks and is compressed from about 9.5 s. The curve C0shows the current I as a function of time. When the obstacle blocks the downward travel of the slat62, the screen4does not immediately compress. Indeed, for several seconds, between 3.25 s and about 9.5 s, in the example ofFIG. 4, the actuator100can continue to rotate the winding shaft8in the direction lowering the screen4, which corresponds to reacting the vertical play between the slats6of the screen4situated below the box12as well as a localized deformation of the screen4, which tends to move radially away from the axis X2while unwinding inside the box12. During this transitional phase, between 3.25 s and about 9.5 s after the beginning of the movement and as shown inFIG. 4, the current I oscillates with a relatively small total amplitude ΔI around I0.

Upon starting up the motor103, the current I has major fluctuations that are not taken into account by the stop detection function, since they correspond to starting up the actuator100. During approximately the first three seconds and after its stabilization, the current I is centered on the value I0, which corresponds to the aforementioned operation under a driving load. Once an obstacle is encountered, as identified by the point P inFIGS. 4 and 5, the current I globally oscillates around the value I0with the amplitude ΔI. When the winding of the screen4is completely blocked, the current I increases greatly and the value of the digital signal S(I) exceeds the value Iref, about 9.5 s after startup in the example ofFIG. 4, which is detected in the second elementary step502, as explained above.

The present invention makes it possible to anticipate the blocking of the screen4against an obstacle by adding, in addition to the stop detection function that is implemented in the first step a1, including elementary steps500and502, and which detects the overtorque C103exerted by the motor103based on the excess of the value Iref by the value of the digital signal S(I), a function protecting the carrier product that is implemented in a second step b and that makes it possible to react from the beginning of the oscillation phase of the current I, i.e., as soon as possible after the screen4has encountered an obstacle, when it is in the process of deforming locally and temporarily, while the screen4has just become a driven load for the actuator100. In other words, this function of protecting the carrier product makes it possible to detect an imminent blocking of the screen4, before this blocking actually occurs.

To that end, the control method according to the invention comprises, in addition to the elementary steps500,502and504, additional elementary steps506to516during which several operations are done by the microprocessor1092A of the electronic unit109. The elementary steps506and516are carried out by the same equipment as the elementary steps500,502and504, such that the function of protecting the carrier product does not cause an excess cost in terms of equipment relative to the stop detection function.

InFIG. 3, bracketacovers steps a1 and a2 belonging to the stop detection function, implemented during the first method step, while bracketbcovers the steps specific to the function of protecting the carrier product, implemented during the second method step.

In practice, it is provided that elementary steps506to516of the function for protecting the carrier product are only implemented if the comparison in elementary step502does not make it possible to detect an overtorque C103, in other words if the value of the digital signal S(I) remains below the value Iref.

During elementary step506, the digital signal S(I) is averaged, for example over the last twelve measured values. Thus, if the current I is measured every 5 ms, the current I at the output of step506is a current averaged over the previous 60 ms.

S(Ī) denotes the averaged signal obtained at the output of elementary step506. This signal S(Ī) is also the input signal of the following elementary step508.

A first digital processing operation done during elementary step508makes it possible to generate a first processed digital signal S1.

InFIGS. 4 and 5, curve C1shows the signal S1as a function of time t. It will be noted that this curve corresponds to a fixed current value I1during approximately the first second of the lowering of the apron4. This corresponds to the determination of a pre-established value for the signal S1during the startup of the actuator100. The value I1is very different from the value I0. In other words, the processing of elementary step508is neutralized, for example, during the first second after the startup of the lowering of the screen4and the signal S1retains the value I1. This avoids an unfounded detection of an obstacle due to variations in the current I upon startup of the motor103.

The signal S1is next processed in an additional elementary step510during which a second digital processing operation is applied to the signal, which becomes the signal S′1at the output of elementary step510. During another elementary step512, a third digital processing operation is applied to the signal S′1, which then becomes a second processed digital signal S2. For example, this third digital processing operation may be a shift of the signal S′1in value. Such a value shift may also constitute the first or second digital processing operation, respectively carried out in the elementary steps508and510.

The first digital processing operation applied during elementary step508may be the application of a low-pass filter, which may have a finite or infinite impulse response, as chosen by the designer of the electronic unit109.

The second digital processing operation applied to elementary step510is preferably of the same nature as that applied to elementary step508, with other specific parameters of this processing operation by modifying time constants that may for example affect the gain or the characteristic frequencies used.

During an elementary step514, the first and second digital signals S1and S2are compared in order to establish whether the actuator100is in a situation such that the screen4having encountered an obstacle is in the process of locally deforming below and/or inside the box12, for example because it is unwinding abnormally in the box12, before the unwinding is completely blocked. This situation takes place in the example over a period of time Δt, which extends between 3.25 s and about 9.5 s inFIG. 4. In other words, the comparison of elementary step514makes it possible to detect whether the screen4is in the process of locally deforming, while generating relatively low amplitude current variations, before being completely blocked and compressed against the obstacle, from about 9.5 s.

InFIGS. 4 and 5, curve C2shows the signal S2as a function of time t.

Upon startup, i.e., during the first second, the value of the digital signal S2is set at a value I2greater than the value I1and very different from the value I0, for the same reasons as explained above for the digital signal S1.

It is considered that the apron4encounters an obstacle at a moment t1=3.25 s after the beginning of its lowering, which represents the point P inFIGS. 4 and 5. The digital signal S1can be a smoothed version of the signal S(I), due to the digital processing applied in elementary step508. Based on the digital processing operations respectively applied in elementary steps508,510and512, it is possible to dynamically determine that an obstacle has been encountered, that the screen4is unwinding abnormally in the box12and that imminent blocking of the screen4should be anticipated through the comparison of the first and second digital signals S1and S2. In this example, imminent blocking of the screen4is determined when the first digital signal S1, which is an image of the current I at that moment, assumes a value greater than or equal to the second digital signal S2, which takes place from a moment t2identified by point Q inFIGS. 4 and 5. In another example, according to the digital processing operations applied to the signals during elementary steps508,510and/or512, the imminent blocking of the screen4is determined when the second digital signal S2assumes a value greater than or equal to the first digital signal S1. According to another example, the imminent blocking of the screen4is determined when the shift Δ½ between the instantaneous values of the first and second digital signals S1, S2is above a predefined threshold.

When imminent blocking of the screen4is determined, an elementary step516is carried out during which the motor103is stopped, an alarm is activated and/or a movement of the actuator100in the opposite direction is initiated, then the motor103is stopped, using an approach similar to that mentioned above regarding elementary step504. In practice, elementary step516can be identical to elementary step504.

In the example ofFIG. 4, the moment t2is at 3.47 s after the beginning of the lowering of the screen4, or 0.22 s after the obstacle has been encountered by the screen4at moment t1. Thus, the function of protecting the carrier product in step b makes it possible to obtain a reaction time, in case of obstacle over the course of the lowering, of 0.2 s, while this reaction time is about 6 s, or between 3.25 s and about 9.5 s, with the stop detection function of steps a1 and a2. The reactivity of the control means of the actuator100, i.e., of the electronic unit109, is therefore improved by the function of protecting the carrier product of the invention.

The stop detection function cannot, however, be replaced by the function of protecting the carrier product because the former acts as a safety function, necessary in certain usage scenarios, for example when stopped on the lower stop, where the unwinding of the screen4in the box12is very limited. Furthermore, the detection sensitivity and the reactivity of the function of protecting the carrier product risk causing false detections, which is not the case for the stop detection function. They are both therefore highly complementary.

Once elementary step516has been carried out, imminent blocking of the screen4is anticipated, even if the comparison between the signal S1and the signal S2again provides another result. In this sense, the curves C0, C1and C2inFIGS. 4 and 5are theoretical because, due to step516, the current I has a zero value shortly after the moment t2, in reaction to the imminence of blocking. These curves show what could occur if the function of protecting the carrier product was not implemented.

In the case where the comparison between the signals S1and S2does not provide any indication of immediate blocking of the screen4, elementary step500is implemented again, at the predetermined measuring frequency.

Elementary steps510and512constitute a group of elementary steps520during which a sort of template or dynamic model is created formed by the digital signal S2and represented by the curve C2, which the digital signal S1, which substantially corresponds to the shunting current I after digital processing, is compared to the predetermined measuring frequency. This template or dynamic model S2corresponds to a value digitally processed from the digital signal S1.

The invention makes it possible to take into account current variations with a relatively low intensity, ΔI, around the value I0, after a startup period of about 1 s, to anticipate a blocking risk of the screen4, before the latter actually becomes a driven load. In other words, the invention, which is based on the detection of a deformation phenomenon of the screen4that takes place during the period Δt shown inFIG. 4, makes it possible to use this period to react, if applicable using elementary step516, before the output torque C103delivered by the motor103increases considerably, to the point that the value of the digital signal S(I) reaches or exceeds the value Iref, as shown inFIG. 4.

In another embodiment, it is also possible to use the information provided by the function of protecting the carrier product to adjust the detection threshold of the stop detection function. The function of protecting the carrier product then corresponds to a function for anticipating a torque peak.

It will be noted that the same current I is used, from elementary step500, both in elementary steps502and504, in the context of the stop detection function, to detect the torque C103exerted by the motor103on the winding shaft8, and in elementary steps506to516as part of the function of protecting the carrier product, to detect the deformation phenomenon of the screen4.

Elementary steps506to516are carried out by the electronic unit109like elementary steps502and504, such that the detection of a deformation phenomenon of the screen4is obtained without it being necessary to add control members in the actuator100. In other words, the additional detection, which makes it possible to anticipate a blocking situation of the screen4owing to elementary steps506to516, is based on calculations that, in practice, do not require adding electronic components in the electronic unit109, which traditionally comprises the microprocessor1092A and, most often, one or several data storage memories, such as the memory1092B.

Since elementary steps506to516are carried out in the electronic unit109, it is possible to configure these steps by varying the digital values used by the microprocessor1092A for elementary steps508,510and512. For example, depending on the digital processing operations applied in elementary steps508and510, it is possible to vary a cutoff frequency of a filter, characteristic frequencies or gains. Regarding elementary step512, the value of the shift may also be adjusted. These adjustments may be done by programming the electronic unit109using the centralized controller30, the remote control32or a computer temporarily connected to the electronic unit109during commissioning of the installation2.

The parameterizable nature of the electronic unit109makes it possible to take data into account specific to the installation2, such as the weight or size of the screen4or the diameter of the winding shaft8. The parameterizable nature of the electronic unit109also makes it possible to take account of the “quality” of the slides14, i.e., their truly straight and vertical nature and their inner surface condition, which may be related to whether the installation2is new or older. The parameterizable nature of the electronic unit109also makes it possible to take account of the ambient temperature, which may affect the behavior of the screen4, in particular, in case of negative temperature, the sliding of the ends of the slats6in the slides14may have hard spots related to frost that may form, without any additional temperature measurement.

Thus, to carry out the method according to the invention, one begins by configuring the electronic unit109, i.e., setting or adjusting its operating parameters, based on the sensitivity level selected for the detecting the deformation of the screen4and/or the ambient temperature. This parameterization or this adjustment may be done by selecting certain values in the memory1092B or entering values in said memory.

The parameterizable nature of the electronic unit109even makes it possible to deactivate the part of the method corresponding to the function of protecting the carrier product and based on detecting the deformation phenomenon of the screen4, by choosing, for elementary steps508,510and512, parameters such that the signal S1remains strictly lower than the signal S2at all times. This may be the case for an installation2whereof the slides14are very damaged or that is working under extreme temperature or load conditions, in which case the function of protecting the carrier product is not appropriate, since it would cause false detections.

The function of protecting the carrier product may also be deactivated if hard spots upon lowering in the slides14are numerous and/or major, since the mechanics of the carrier product are not suitable, in particular following excessive aging of the carrier product, or during the renovation of an installation, during which the rolling shutter is modified by going from manual driving by a strap to motorized driving, or an incompatible change in motor means.

In summary, the function of protecting the carrier product can be deactivated to operate actuators mounted in installations not appropriate for that solution, in particular, in terms of quality of the slides14or operating conditions.

Deactivating the function of protecting the carrier product or adjusting the sensitivity of the function of protecting the carrier product based on the ambient temperature measured at the actuator100makes it possible to prevent the detection of blocking of the screen4from being too sensitive.

This deactivation or adjustment therefore makes it possible to obtain the robustness of the function of protecting the carrier product from untimely activations, under low temperature conditions where the slats of the screen4may be frozen, the slides14hindered by frost or the resisting torque greater within the gear motor102.

Deactivating or adjusting the sensitivity of the function of protecting the carrier product may be done at the installer's initiative, which allows the latter to take account of the actual implementation conditions of the installation2, in particular when the apron4or its actuator100are damaged or mounted imperfectly.

The independent nature of elementary steps502and514allows an independent adjustment of the detection sensitivity of the torque C103exerted by the motor103, corresponding to the stop detection function, and on the other hand the detection of the deformation phenomenon of the screen4corresponding to the function of protecting the carrier product. Indeed, the reference value Iref may be determined independently of the parameters used in elementary steps508,510and512.

The invention is shown inFIG. 3in the case where the digital signal S(I) used in elementary step502is from elementary step506. Alternatively, the signal used in elementary step502may be the signal S(Ī) from elementary step500or the signal S1from elementary step508. In this case, the signal used in elementary step502is averaged and optionally digitally processed, while remaining representative of the output torque C103of the motor103. In this case, elementary step506, and optionally elementary step508, belong to step a1.

Elementary step506is optional. It may be omitted or integrated into elementary step508.

The invention is shown inFIGS. 1 and 2in the case of its use with a screen4of rolling shutter formed by several slats6. It is, however, applicable to other types of blackout screens, whether involving closure or sun-shading screens. However, the invention is particularly advantageous when the screen is a screen with slats or open-worked members made up of elements articulated to one another with a possibility of relative movements, such as slats or links of a gate, since the relative movements of these parts of the screen over the period Δt generate current variations like those shown over this period inFIG. 4.

The numerical values, in particular the durations, mentioned in this description are indicative and in practice depend on the installation conditions of the actuator100.

The embodiments and alternatives considered above may be combined to generate new embodiments of the invention, without going beyond the scope of the invention defined by the claims.