EP0636340A1 - Suction cleaner having floor nature detecting means - Google Patents

Abstract

Vacuum cleaner comprising a suction body having an air inlet (11), an air outlet (21) and a hose fitted with a nozzle connected to the air inlet of the suction body, which body houses a dust chamber (10) communicating with the air inlet (11), and a housing (20) for a fan (23) driven by an electric motor (22), this housing (20) communicating with the dust chamber (10) and air outlet (21), this vacuum cleaner also comprising: - a first sensor (14), for sensing the floor surface, is [and] a pressure sensor which supplies a signal corresponding to the air pressure measured at a first measurement point (15) in the path of the air drawn in by the vacuum cleaner, which signal has pseudo-periodic oscillations whose maxima ( gamma ) and minima ( epsilon ) correspond in the one case to the outward movements, and in the other to the return movements, of the nozzle over the floor surface during the cleaning operation, this signal having an amplitude difference ( DELTA P), between these maxima and minima, that varies according to the kind of floor surface being cleaned, and in that the computing means (30, 40) determine the kind of floor surface being cleaned on the basis of this difference in amplitude ( DELTA P); - computing means that use the signals supplied by the first sensor in order to output a classification signal indicating the condition of the floor surface during the course of the cleaning operation. <IMAGE>

Description

• un premier capteur, dit capteur de sol, pour fournir un signal fonction de caractéristiques de l'état de surface du sol détectées par la buse lors de l'opération de nettoyage ;
• des moyens de calcul prenant en compte les signaux fournis par ce premier capteur, pour fournir un signal de classification de l'état de surface du sol, lors de l'opération de nettoyage.

A vacuum cleaner includes a vacuum cleaner body having an air inlet and an air outlet, and a hose having a nozzle coupled to the air inlet of the vacuum cleaner body , this vacuum cleaner body including a dust chamber communicating with the air inlet, and a housing for a fan driven by an electric motor, this housing communicating with the dust chamber and the air outlet, this vacuum cleaner comprising in addition :

• a first sensor, called a soil sensor, for supplying a signal which is a function of characteristics of the soil surface condition detected by the nozzle during the cleaning operation;
• calculation means taking into account the signals provided by this first sensor, to provide a classification signal for the surface state of the soil, during the cleaning operation.

The invention finds its application in the field of manufacturing of domestic or industrial vacuum cleaners.

• un premier capteur, qui est un capteur de courant, pour détecter les changements du courant d'alimentation d'une brosse électrique placée dans la buse, qui apparaissent au moment précis du passage d'un sol à un autre sol, par exemple lors des changements de sols entre tapis épais, tapis fin, tatami et sol dur, et un circuit pour mémoriser les pics de courant. En effet pendant l'opération de nettoyage, l'utilisateur de l'aspirateur effectue avec la brosse située dans la buse, des allers et retours en frottant le sol. Selon l'état de surface de ce dernier, la charge appliquée à la brosse change, et donc son courant change. Ce courant présente la forme d'une sinusoïde ayant pour fréquence celle de la tension d'alimentation alternative du moteur de la brosse, fournie par le secteur. Ce courant présente d'autre part des variations en forme de pics de l'enveloppe de la courbe sinusoïdale. Ces pics d'amplitude de la sinusoïde apparaissent à chaque changement de direction dans le frottement du sol par la brosse, c'est-à-dire entre un aller, où la brosse est poussée sur le sol, et un retour, où la brosse est tirée sur le sol. Il est important de remarquer que entre ces pics, la valeur du courant représentée par l'amplitude de la sinusoïde est à peu près constante quel que soit le sol. La valeur du courant varie seulement lorsque les pics apparaissent et de telle manière que l'amplitude de ces pics est plus grande pour les tapis épais que pour les tapis fins, et est la plus petite pour les sols durs. Lorsque la brosse ne touche pas le sol, aucun pic n'apparaît ;
• un second capteur, qui est un capteur de pression, formé d'un capteur piézoélectrique disposé dans le corps de l'aspirateur relié à un tuyau pour détecter la pression d'air à la partie succion du ventilateur, entre le chambre à poussière et la face succion de ce ventilateur, pour fournir un signal fonction de cete pression.

A vacuum cleaner provided with the elements described above is known from European patent application EP 0 467 347. The document describes a vacuum cleaner having means for adjusting the power of the fan drive motor according to the nature or the state. of the soil surface rubbed by the nozzle. These means include:

• a first sensor, which is a current sensor, for detecting changes in the supply current of an electric brush placed in the nozzle, which appear at the precise moment of the passage from one soil to another soil, for example during changes of soil between thick carpet, fine carpet, tatami and hard soil, and a circuit to memorize current peaks. Indeed during the cleaning operation, the user of the vacuum cleaner performs with the brush located in the nozzle, back and forth by rubbing ground. Depending on the surface condition of the latter, the load applied to the brush changes, and therefore its current changes. This current has the shape of a sinusoid having as frequency that of the AC supply voltage of the brush motor, supplied by the sector. This current on the other hand has variations in the form of peaks of the envelope of the sinusoidal curve. These amplitude peaks of the sinusoid appear at each change of direction in the friction of the ground by the brush, that is to say between a go, where the brush is pushed on the ground, and a return, where the brush is pulled to the ground. It is important to note that between these peaks, the value of the current represented by the amplitude of the sinusoid is almost constant whatever the ground. The value of the current varies only when the peaks appear and in such a way that the amplitude of these peaks is greater for thick carpets than for fine carpets, and is smallest for hard floors. When the brush does not touch the ground, no peak appears;
• a second sensor, which is a pressure sensor, formed by a piezoelectric sensor disposed in the body of the vacuum cleaner connected to a pipe for detecting the air pressure at the suction part of the fan, between the dust chamber and the suction side of this fan, to provide a signal as a function of this pressure.

• des moyens de calculs pour fournir un signal de classification de l'état de surface des sols, entre TAPIS EPAIS, TAPIS MINCE, TATAMI, et SOL DUR, à partir des pics de courant de la brosse électrique de base. Ces moyens de calcul incluent un microprocessuer qui compare les valeurs retenues des pics de courant avec des valeurs de courant de référence prédéterminées et prémémorisées. A partir de là, ce microprocesseur établit la classification des sols par comparaison avec ces valeurs de courant de référence. D'autre part, ce microprocesseur compare les valeurs de pression fournies par le second capteur, avec des valeurs de référence de pression prédéterminées et prémémorisées correspondant aux différents sols possibles. Ce microprocesseur fournit ensuite un signal de réglage de la puissance du moteur pour obtenir, en sortie de la chambre à poussière, une valeur de pression conforme à la valeur de pression prédéterminée et prémémorisée correspondant à la classe du sol calculée. Le microprocesseur peut aussi fournir éventuellement un signal interrupteur du moteur de brosse.

The vacuum cleaner known from the cited document further comprises:

• calculation means to provide a classification signal for the surface condition of the soil, between THICK CARPET, THIN CARPET, TATAMI, and HARD GROUND, from the current peaks of the basic electric brush. These calculation means include a microprocessor which compares the retained values of the current peaks with predetermined and pre-stored reference current values. From there, this microprocessor establishes the classification of soils by comparison with these reference current values. Else On the other hand, this microprocessor compares the pressure values supplied by the second sensor, with predetermined and pre-memorized pressure reference values corresponding to the different possible soils. This microprocessor then supplies a signal for adjusting the power of the engine in order to obtain, at the outlet of the dust chamber, a pressure value conforming to the predetermined and pre-stored pressure value corresponding to the calculated soil class. The microprocessor can also optionally provide a switch signal from the brush motor.

This known vacuum cleaner has a drawback in that the soil detector is a current detector linked to the electric nozzle brush. Thus, the detection of peaks, allowing the indication of different soils, can only be made when a brush is systematically used in the nozzle, that is to say is both present and in rotation. However, the systematic use of a brush is not practical. In particular, the electric brush tends to scatter the crumbs instead of attracting them to the nozzle when the floor is a smooth covering or a level carpet. In general, the user wants the brush to be out of service for smooth floors and level carpets. Therefore, the device described is only useful for distinguishing thick carpets from medium carpets, and in this case, it appears that the levels of the current peaks are not different enough to make this distinction in a correct manner.

The object of the present invention is to provide a vacuum cleaner which makes it possible to obtain information relating to the ground, independent of the putting into service of the brush.

According to the invention this object is achieved by means of a vacuum cleaner provided with the elements described in the preamble and further characterized in that the first sensor, called the soil sensor, is a pressure sensor which provides a signal as a function of the pressure of the air measured at a first measurement point on the path of the suction air flow of the vacuum cleaner, this signal having pseudo-periodic oscillations, the maxima and minima correspond for the outward and for the others to the returns of the nozzle on the ground during the cleaning operation, this signal presenting a difference in amplitude, between these maxima and minima, which varies according to the class of the cleaned soil, and in that the calculation means determine the class of the cleaned soil, as a function of this difference in amplitude.

This vacuum cleaner has the advantage that soil detection is very good, because it results from a sensor whose measurement is directly influenced by the action of the soil on the suction air flow and does not have to be taken taking into account parameters related to motors or power supplies.

In addition, this vacuum cleaner has the advantage that the measurement does not depend on the compulsory commissioning of the electric brush located in the nozzle, since the measuring point of the sensor is located on the path of the suction flow. So detection can be done for all floors, even hard floors cleaned without brushing.

Furthermore, this vacuum cleaner has the advantage of better longevity than the known device, because in general the brush motor of the nozzle has a shorter lifespan than the main motor of the vacuum cleaner; therefore the device according to the invention, which is not linked to the brush motor, can last longer than the known device.

In one implementation, this vacuum cleaner is characterized in that, the signal from the first pressure sensor called the soil sensor having a so-called average amplitude, between the amplitudes of the maxima and minima, which varies according to the class of the soil cleaned, the calculating means determine the class of the soil cleaned jointly as a function of the difference in amplitude between maximum and minimum and of said average amplitude of the signal from the soil sensor.

In this implementation, this vacuum cleaner has the advantage that the detection of different floors is further improved.

The present invention also aims to provide a vacuum cleaner which has a better adjustment of the suction pressure according to the class of the soil, than the known vacuum cleaner.

According to the invention, this object is achieved by means of a vacuum cleaner characterized in that it comprises setpoint means for determining, as a function of the class of the soil calculated, a setpoint for said average amplitude of the signal of the first pressure sensor, so as to adjust the suction pressure appropriately according to the calculated soil class.

This vacuum cleaner has the advantage that the detection is improved, the set value for said average amplitude of the signal from the first pressure sensor can be determined more precisely.

In one implementation, this vacuum cleaner is characterized in that it comprises control means for determining a value for adjusting the supply voltage of the fan motor to supply the electric power which makes it possible to obtain the set value for the average amplitude of the signal from the first pressure sensor.

This vacuum cleaner has in particular an extremely important advantage over the known vacuum cleaner: in fact, according to the invention, both the detection of soil and the adjustment of the suitable suction pressure according to the detected soil are carried out by means of a single sensor. So not only according to the invention the detection is more precise, the adjustment of the working pressure is more precise, but also these results are achieved with great economy of means. It is recalled that in the known vacuum cleaner, the current sensor intervened only in the detection of soil, and the pressure sensor located at the outlet of the dust chamber intervened only in the adjustment of the working pressure. Two sensors were therefore necessary to fulfill the two functions. The vacuum cleaner according to the invention achieves these two functions with one sensor instead of two.

The present invention also aims to optimize the detection of the cleaned floor and the adjustment of the suction pressure level.

According to the invention, this object is achieved by means of a vacuum cleaner characterized in that the measurement point of the first pressure sensor called the soil sensor is located at the entrance to the dust chamber.

This vacuum cleaner then has many advantages. First of all, the detection accuracy is greatly improved, since the measurement is influenced by the action of the ground, practically without intermediaries, and in any case without damping.

Then the adjustment of the suction pressure is also improved, because this pressure is adjusted directly at the inlet of the dust chamber, instead of being at the outlet as in the known vacuum cleaner. So the pressure setting is more precise and more adequate than in the known vacuum cleaner.

• un premier signal fonction de ladite valeur moyenne de la pression mesurée sur le trajet du flux d'aspiration par le premier capteur de pression :
• un second signal fonction de la valeur de différence d'amplitude entre maxima et minima des oscillations de la pression mesurée sur le trajet du flux d'aspiration par le premier capteur de pression.

In one implementation, this vacuum cleaner is characterized in that the calculation means comprise so-called pre-treatment means, which receive as input the signal supplied by the first pressure sensor, called the soil sensor, and which supply as an output, resulting of this pretreatment:

• a first signal as a function of said average value of the pressure measured on the path of the suction flow by the first pressure sensor:
• a second signal which is a function of the amplitude difference value between maximum and minimum of the oscillations of the pressure measured on the path of the suction flow by the first pressure sensor.

This vacuum cleaner has the advantage of using, for this pretreatment, only simple calculation means, with additions or subtractions or tests, and not multiplications or divisions. These calculation means are therefore inexpensive and easy to implement to obtain a device at low cost.

In one implementation, this vacuum cleaner is characterized in that, the calculation means further comprise a classifier deduction block, which receives as input the first and second signals from said preprocessing means, and which outputs corresponding classes , according to predetermined rules, on the detection of several different surface states of the floor to be cleaned.

In one implementation, this vacuum cleaner is possibly characterized in that the classifier deduction block provides two classes as output corresponding to the detection of two different surface states of the floor to be cleaned which are a "CARPET" state and a "SOL" state HARD and SMOOTH.

This vacuum cleaner has the advantage of using only very simple means of deduction which provide the results very quickly.

• un troisième signal fonction de la valeur moyenne de la différence entre les pressions à l'entrée et à la sortie de la chambre à poussière.

In one implementation, this vacuum cleaner is characterized in that it comprises a second pressure sensor, to supply a signal which is a function of the difference of the air pressures measured between the inlet and the outlet of the dust chamber, and in that the preprocessing means receive this signal and output:

• a third signal depending on the average value of the difference between the pressures at the inlet and at the outlet of the dust chamber.

This measure improves the robustness of the soil classification. Optionally, this measurement can be used to provide the fill rate of the dust chamber.

In one implementation, this vacuum cleaner is characterized in that it further comprises an electric brush disposed in the nozzle and means for adjusting the electric power of the motor of this brush, called the auxiliary motor as a function of the class of the soil. calculated.

In one implementation, this vacuum cleaner is characterized in that the means for adjusting the power of the auxiliary motor include a setpoint block for determining, by direct conversion according to the detected soil class, a voltage adjustment value supply of the auxiliary motor to provide the power which enables the brush placed in the nozzle to be put into service or not, according to the detected soil class.

This vacuum cleaner has the advantage that starting and adjusting the auxiliary brush motor is completely independent of the adjustment of the main motor depending on the soil.

• la FIG.1 représente un aspirateur muni de ses éléments principaux et des 2 capteurs de pression ;
• la FIG.2 représente, en blocs fonctionnels, l'aspirateur et le dispositif de traitement des signaux des capteurs de pression, pour le contrôle du moteur principal de ventilateur et d'un moteur auxiliaire, de brosse dans la buse, et la détection du taux de remplissage de la chambre à poussière.
• la FIG.3A représente les signaux des premier et second capteurs de pression à puissance constante du moteur principal, avec des taux de remplissage de la chambre à poussière différents, sur un sol "TAPIS" ;
• la FIG.3B représente les signaux des premier et second capteurs de pression, à puissance constante du moteur, à taux de remplissage du sac à poussière identique, avec des sols différents.

The invention is described below in detail with reference to the attached figures among which, schematically:

• FIG.1 represents a vacuum cleaner provided with its main elements and 2 pressure sensors;
• FIG. 2 represents, in functional blocks, the vacuum cleaner and the device for processing the signals from the pressure sensors, for controlling the main fan motor and an auxiliary motor, brush in the nozzle, and the detection of the filling rate of the dust chamber.
• FIG.3A represents the signals of the first and second pressure sensors at constant power of the main engine, with different filling rates of the dust chamber, on a "CARPET"floor;
• FIG. 3B represents the signals of the first and second pressure sensors, at constant engine power, at the same dust bag filling rate, with different soils.

With reference to FIG. 1, a vacuum cleaner for domestic or industrial use comprises a vacuum cleaner body 1, provided with means, not shown, to be easily moved on a floor to be cleaned, for example wheels or pads, or a combination of these.

• un premier logement 10 constituant la chambre à poussière, communiquant avec l'entrée d'air 11 ;
• un second logement 20 pour un ventilateur 23 entraîné par un moteur 22. Le logement du ventilateur et du moteur communiquent avec la chambre à poussière 10 d'une part, et la sortie d'air 21 d'autre part. Le ventilateur 23 présente un côté succion 23a vers la chambre à poussière 10, et un côté soufflerie vers la sortie d'air 21.

The vacuum cleaner body is provided with an air inlet 11 and an air outlet 21, and essentially comprises two housings:

• a first housing 10 constituting the dust chamber, communicating with the air inlet 11;
• a second housing 20 for a fan 23 driven by a motor 22. The housing of the fan and the motor communicate with the dust chamber 10 on the one hand, and the air outlet 21 on the other hand. The fan 23 has a suction side 23a towards the dust chamber 10, and a blower side towards the air outlet 21.

The fan housing 20 is made dustproof from the dust chamber by a filter F1 detachably disposed in the communication opening of the dust chamber 10 with this housing 20. The air outlet 11 is also protected dust by a filter F2 detachably disposed between the blower side 23b of the fan and this air outlet 21.

In general, a dust bag 12 forming a filter is removably placed in the dust chamber. This bag has an opening directed towards the air inlet 11, and is positioned as dust-tight as possible behind this air inlet 11.

The vacuum cleaner further comprises a hose generally formed of a flexible part and a rigid extension terminated by a nozzle. The end of the pipe opposite the nozzle is coupled with the opening of the air inlet 11. These various parts are not shown in FIG.1.

The operation of the vacuum cleaner includes the connection of the fan motor to an alternating voltage source to create, by the action of the fan, a depression in the nozzle, so as to suck up the dust, crumbs, small debris and others which become found on floors to be cleaned. The action of cleaning includes actuation of the rigid part of the hose by the user, according to a back-and-forth movement of the nozzle on the floor to be cleaned, forming back-and-forth movements of the nozzle on the floor in a pseudo-periodic manner, the pseudo-period a round trip being of the order of 0.5 seconds, and generally less than 2 seconds.

When the nozzle is pushed forward by the user by means of the rigid part of the pipe, in the "go" part of the pseudo-period, the nozzle is pressed against the ground, and therefore the resistance to air increases, the flow in the hose decreases, and it follows that the vacuum in the vacuum cleaner hose increases.

When the nozzle is pulled backwards, on the other hand, in the "return" part of the period, the nozzle is slightly raised with respect to the floor to be cleaned and the vacuum in the vacuum cleaner hose decreases.

So at the change of direction of the nozzle, that is to say between a round trip and a reverse, a variation of the depression appears. This variation is also pseudo-periodic, with the pseudo-period of the back and forth movements of the nozzle. These variations in depression at the nozzle, which can also be called oscillations in the amplitude of the pressure in the nozzle and the pipe, constitute quantities which are measurable.

Indeed, each "go" of the nozzle corresponds in this pseudo-periodic variation, to a maximum of the amplitude of the pressure, and each "return" of the nozzle corresponds to a minimum of the amplitude of the pressure in the vacuum cleaner hose. It is important to note that the value of the pressure amplitude remains maximum throughout the duration of the "outward" operation, as well as the pressure amplitude remains minimum throughout the duration of the "return" operation ". Between the maximum and minimum pressure, the pressure variation, which corresponds to an abrupt change of direction of the nozzle on the ground, is abrupt. Thus the curve representing the amplitude of the pressure as a function of time has practically the form of a pseudo-periodic square signal.

The difference in amplitude of the pressure between the "back and forth", that is to say the difference between the amplitude or value of pressure at maximum and the amplitude or value of pressure at minimum of the pseudoperiodic variation, strongly depends on the surface condition or the nature of the soil to be cleaned. Thus, this difference in amplitude of the oscillations is large if the round trips of the nozzle are carried out on a thick carpet; this difference in amplitude decreases when the depth of the mat decreases; and this amplitude is almost zero on hard and smooth ground.

On the other hand, the average amplitude of the pressure in the nozzle, that is to say the average value of the amplitude measured between the maxima and minima of amplitude with respect to the zero pressure also depends strongly on the 'surface condition or type of soil to be cleaned. This average amplitude is large when the nozzle is in the presence of a thick carpet: it decreases when the depth of the carpet decreases and it is at a minimum value, but not zero, when the nozzle is in the presence of hard ground.

These variations in pressure amplitude can be measured in the nozzle of the vacuum cleaner hose. However, it is preferable, for reasons of ease of implementation, to measure them at the level of the air inlet 11 of the body 1 of the vacuum cleaner.

These variations are also visible in the part of the vacuum cleaner body located at 23a between the dust chamber and the fan or else at 23b at the outlet of the dust chamber. But in these places the oscillations are damped by the presence of dust and by that of the various filters (dust bag 12 and possibly filter F1) themselves.

Consequently, a measurement made at the air inlet 11 corresponds more correctly to the conditions pressure which exist in the nozzle itself and provides a more convincing indication of the surface condition of the soil.

This measurement of the variations in amplitude of the pressure which appear at each change of direction of the nozzle is carried out by means of a pressure sensor 14 whose measuring point 15 is disposed at the level of the air inlet 11, for example before the dust bag 12. This pressure sensor can be a silicon sensor provided with a flexible tube 17, the end of which is brought to the measurement point 15. The body of the sensor 14 itself can be fixed on a circuit board 29 disposed in the body 1 of the vacuum cleaner, outside the path of the air flow.

It also appears that the pressure variations during the round trips for the same soil, and the same engine power are slightly influenced by the filling of the dust chamber. This is why in order to improve the robustness of the soil detection, a measurement of the pressure difference between the outlet and the inlet of the dust chamber is provided.

For this purpose, there is, in the body of the vacuum cleaner, a second pressure sensor 24 of the same type as the first pressure sensor 14, provided with a flexible hose 27, the end of which is brought to the measuring point 25 suction side 23a of the fan. The body of the pressure sensor 24 can be fixed on a circuit board arranged in the body of the vacuum cleaner outside the path of the air flow. the body of the pressure sensor 24 can for example be fixed on the same circuit board 29 as the body of the pressure sensor 14. Preferably this second sensor 24 is coupled to the first sensor 14 to provide a measurement of the pressure difference to the dust chamber terminals. The difference between the average pressures which exist at the measurement point 15, at the inlet of the dust chamber, and at the measurement point 25, at the outlet of this chamber can be obtained in a simple manner. To this end, the pressure sensor 24 is a sensor differential, and a T referenced 28 is applied to the flexible pipe which takes the pressure at the measurement point 15 to apply this pressure measured both on the sensor 14 inlet and on the sensor 24 outlet of the dust chamber. Thus the sensor 24 receives both the pressures at the measurement points 15 and 25.

In alternative embodiments, the measuring point 25 may be on one side or the other of the dust filter F1, that is to say in fact, either at the outlet 23b of the dust chamber 10, in this dust chamber behind the dust bag 12, or else in position 23b between the filter F1 and the suction face of the fan 23 in the housing 20.

It should be noted that, unlike the vacuum cleaner disclosed in European patent application EP 0467 347, cited in the prior art, this pressure sensor 24 disposed at the outlet of the dust chamber is not essential for the adjustment of the working pressure of the vacuum cleaner, adjustment which will be described later. This second pressure sensor 24 is according to the invention only intended to improve the robustness of the classification of the soil. Optionally, the differential pressure measurement can make it possible to deduce an indication of the filling rate of the dust chamber.

In one implementation, it is possible to seek to detect the pressure conditions relating to 3 or 4 different soils, for example as known from the document cited under the prior art: thick carpet, fine carpet, tatami, and hard soil and smooth; and the corresponding settings of the fan motor power can be provided.

The curves of FIG. 3A and 3B illustrate the implementation of the detection by the two pressure sensors, respectively 14 and 24.

Curve C in FIG. 3B shows the pressure P in mbar measured by the sensor 14 at the measurement point 15 at the inlet of the dust bag as a function of the time t measured in seconds (s), and the curve D of this same FIG. 3B shows the pressure P in mbar measured by the sensor 24 at the measurement point 25 at the outlet of the dust bag in function of time t measured in seconds. These measurements are made at constant power from the motor 22 of the fan 23, and with the same dust bag filling rate for all parts of the curve.

Remember that 1 bar = 10⁵ Pa (Pascal).

The parts C1 and D1 of curve relate to a cleaning condition where the nozzle undergoes back and forth on a ground provided with a thick carpet, with long strands, the parts C2 and D2 concern a condition of cleaning on medium thickness carpet, and parts C3 and D3 concern a cleaning condition on hard floor.

These curves show in the parts C1 and D1, on the one hand, and C2 and D2 on the other, oscillations formed by maxima γ1, γ2, γ3 considered for example on C1, and minima ε1, ε2, ε3 considered on the same curve C1 representative of the pressure P at the inlet of the dust chamber, when the nozzle goes back and forth on a thick carpet. The pressure maxima, which are here of the order of 82 mbar correspond to the time durations of the order of 1.5 seconds during which the user pushes the nozzle on the belt (back and forth). The pressure minima, which are here of the order of 74 mbar correspond to the time durations of the order of 1.5 seconds during which the user pulls the nozzle on the belt (returns). The variation of the pressure P between the maxima γ1, γ2, γ3 and the minima ε1, ε2, ε3 is extremely abrupt: it corresponds to the changes of direction of the nozzle between back and forth.

The slight irregularities that appear on the maxima or on the amplitude minima are due to noise and must be smoothed when processing the measured data.

The difference in amplitude ΔP between the amplitude P2 of the maxima γ1, γ2, γ3 and the amplitude P1 of the minima ε1, ε2, ε3 is in the example illustrated by FIG.3B of the order of 8 mbar for a carpet, the pressure being measured at the inlet of the dust chamber.

We can see, on the same FIG.3B that the part D1 relating to the pressure measured at the rear of the dust chamber under the same conditions as C1 also shows oscillations between the amplitudes corresponding to the back and forth of the nozzle . On the curve D1, the maxima are noted γ'1, γ'2, γ'3 ... and the minima are noted ε'1, ε'2, ε'3. The average amplitude of the pressure between maximum and minimum is noted PM1 '. But, if the mean amplitude PM 'of the pressure (curve D) is greater at the rear of the dust chamber (PM1' = around 108 mbar for D1) than the mean amplitude PM (curve C) at l front of the dust chamber (PM1 = around 79 mbar for C1), on the other hand the oscillations noted at the rear of the dust chamber (curve D) are more damped: for example for a carpet, the difference of pressure amplitude ΔP between back and forth is about 6 mbar (curve D1) instead of 8 (curve C1) when the pressure is measured at the front of the dust chamber. So it is more favorable to place the pressure sensor which serves as a floor sensor at the front of the dust chamber, rather than at the rear.

The same observations can be made for the parts of curve C2 and D2 relating to a thinner carpet, showing the pressure respectively at the front (curve C2) and at the rear (curve D2) of the dust chamber.

Parts C3 and D3 which concern the conditions where the nozzle performs back and forth on hard ground show that the amplitude of the pressure is identical here for the back and forth. No variation in amplitude
does not appear; there is neither maximum nor minimum. There is only a slight noise.

On the other hand, the determination of the mean pressure amplitudes PM1, in the thick carpet condition (curve C1), PM2 medium carpet (curve C2) and PM3, hard ground (curve C3) shows that this average amplitude goes from 78 mbar (C1), to 69 mbar (C2) and to 64 mbar (C3). So this average amplitude varies with the surface condition of the soil. In particular, it decreases from thick carpet, to medium carpet and hard floor.

The curve A in FIG. 3A shows the pressure P in mbar measured by the sensor 14 at the measurement point 15 at the inlet of the dust chamber, as a function of the times t measured in seconds, and the curve B of this same FIG.3A shows the pressure P in mbar measured by the sensor 24 at the measurement point 25 at the outlet of the dust chamber, as a function of the time t measured in seconds. These measurements are made at constant power from the fan motor 22, and on a medium belt.

The parts A1 and B1 of curve relate to a condition where the dust chamber, for example provided with a dust bag, is empty, that is to say that the bag is clean and new.

Parts A2 and B2 of the curve relate to a condition where the dust bag shows a filling rate of approximately 50%. It can be seen from these curves that when the dust chamber fills, the pressure at point 15 at the inlet to the dust chamber decreases while the pressure at point 25 at the outlet from the dust chamber increases.

Parts A3 and B3 of the curve relate to the condition where the dust bag is full. It can be seen that the pressure at point 15 is minimum, while at point 25 it is maximum.

Whatever the filling conditions of the dust chamber, the maximum and minimum pressure corresponding to the back and forth of the nozzle are always well measurable on the curves, and especially on the curves A which correspond to the pressure measured at l front of the dust chamber.

The curves A and B of FIG. 1A show that a differential measurement of the average pressure can be carried out between the rear of the dust chamber, at measurement point 25, and the front of the dust chamber, at measurement point 15.

• les amplitudes P2 des maxima γ1, γ2,... pour chaque type de sol,
• les amplitudes P1 des minima ε1, ε2... pour chaque sol, pour évaluer ensuite :
  • la différence d'amplitude $\text{ΔP = P2 - P1}$
  • l'amplitude moyenne : $\text{PM = (P1 + P2)/2}$
    

   L'évaluation de la différence d'amplitude ΔP pour chaque sol permet déjà à elle seule une classification des sols. L'évaluation de l'amplitude moyenne PM permet d'améliorer cette classification. Ensuite l'évaluation par le traitement des mesures de la FIG.3A, de la pression différentielle moyenne entre l'entrée et la sortie : PM'-PM, permet une amélioration supplémentaire de cette classification.The characteristics highlighted in FIG. 3B allow precise ground detection to be achieved. To this end, the measurements of the first pressure sensor 14, called the soil sensor, are carried over to calculation means described below, that is to say:

• the amplitudes P2 of the maxima γ1, γ2, ... for each type of soil,
• the amplitudes P1 of the minima ε1, ε2 ... for each soil, to then evaluate:
  • the difference in amplitude $\text{ΔP = P2 - P1}$
  • the average amplitude: $\text{PM = (P1 + P2) / 2}$
    

The evaluation of the difference in amplitude ΔP for each soil alone already allows classification of the soils. The evaluation of the mean amplitude PM makes it possible to improve this classification. Then the evaluation by the processing of the measurements in FIG. 3A, of the average differential pressure between the inlet and the outlet: PM'-PM, allows an additional improvement of this classification.

For the sake of simplicity, an exemplary implementation will be described below where it is sought to detect only two different surface states of the soil, classified as "carpet" and "hard and smooth soil". It has indeed appeared from experience that this implementation leads to a simple and inexpensive vacuum cleaner, the functions of which correspond best to the most frequent demand of the user. This detection of two possible states of different soils will then lead on the one hand to adjustments of the power of the fan motor, and on the other hand to the automatic triggering of an electric brush placed in the nozzle, possibly.

This is why, in this example of implementation, means are further described for activating the motor of an electric brush located in the nozzle, in the case where the device detects a carpet, or for deactivating this motor, when the nozzle comes to clean a hard and smooth floor.

In this implementation, one could also use the measurement of the two pressure sensors to provide an indication of the filling state of the dust bag.

FIG. 2 represents the soil detection device which makes it possible, from measurements 16, of the pressure sensor 14 applied to the measurement point 15 situated at the entrance to the dust chamber, and as shown in FIG. 3B (curve C), to subsequently supply a signal for controlling the power of the main motor 22 of fan 23 and possibly of the auxiliary brush motor (not shown).

• un bloc de prétraitement 30 qui reçoit en entrée les sorties 16 et 26 du premier et du second capteurs de pression et qui effectue un traitement dit PRE-TRAITEMENT consistant à calculer :
• la valeur moyenne PM des oscillations du signal de sortie 16 du premier capteur de pression 14, relatif à la pression existant à l'entrée 11 de la chambre à poussière 12 ;
• la différence d'amplitude ΔP entre maxima et minima des oscillations du signal de sortie 16 du capteur de pression 14 relatif à cette même pression ;
• la différence des valeurs moyennes PM'- PM des pressions existant à l'entrée 11 au point de mesure 15 et à la sortie 23a ou 23b de la chambre à poussière, au point de mesure 25.

This soil detection device includes:

• a preprocessing block 30 which receives as input the outputs 16 and 26 from the first and second pressure sensors and which performs a so-called PRE-TREATMENT treatment consisting in calculating:
• the mean value PM of the oscillations of the output signal 16 from the first pressure sensor 14, relating to the pressure existing at the input 11 of the dust chamber 12;
• the difference in amplitude ΔP between maximum and minimum of the oscillations of the output signal 16 of the pressure sensor 14 relative to this same pressure;
• the difference of the mean values PM'-PM of the pressures existing at the inlet 11 at the measurement point 15 and at the outlet 23a or 23b of the dust chamber, at the measurement point 25.

This calculation is carried out over time periods or "time windows" T of a sufficient value, for example 2 seconds, during which, in operation of the vacuum cleaner, during a conventional cleaning operation, an average user performs at minus a change of direction of the nozzle between a round trip on the floor to be cleaned.

It will be recalled that the soil sensor 14 has a measurement point 15 disposed in the body 1 of the device, and that its output signal 16 is not linked to the compulsory use of an electric brush in the nozzle.

The operations performed by this preprocessing block 30 are therefore very simple. These are only averages on the one hand, and tests on the other hand to first calculate the average amplitude PM of the pressure at the inlet of the dust bag, to then calculate the difference in average pressures (PM ' - PM) between the exit and the entry of the dust bag, and to also detect the maximum γ1, γ2, γ3 and minimum ε1, ε2, ε3 of pressure coinciding with the back and forth of the base and calculate the differences of amplitudes ΔP between these maxima and minima.

These calculations therefore do not include any multiplication or division, from which it follows that this preprocessing block 30 performing these operations can be very simple.

• 1 à 3 entrées,
• 2 sorties pour les signaux à calculer.

The outputs 31, 32, 33 of the preprocessing block 30 are applied to a deduction block 40, known as a classifier which comprises:

• 1 to 3 entries,
• 2 outputs for the signals to be calculated.

• un signal 31 de la valeur maximale de la différence d'amplitude ΔP entre les maxima et minima des oscillations de pression, du signal fourni par le capteur de sol 14 ;
• un signal 32 de la valeur de l'amplitude moyenne de pression PM fournie par le capteur de sol 14,
• un signal 33 de la différence des amplitudes moyennes de pression (PM' - PM) entre la sortie et l'entrée de la chambre à poussière.

The three inputs of the classifier deduction block 40 consist of the three output signals calculated by the preprocessing block 30:

• a signal 31 of the maximum value of the difference in amplitude ΔP between the maximum and minimum of the pressure oscillations, of the signal supplied by the soil sensor 14;
• a signal 32 of the value of the mean pressure amplitude PM supplied by the soil sensor 14,
• a signal 33 of the difference in mean pressure amplitudes (PM '- PM) between the outlet and the inlet of the dust chamber.

• tapis,
• sol dur et lisse.

Dans ce cas, tous les exemples de tapis sont contre-exemples de sol dur, et VICE VERSA. Par ailleurs, il peut être prévu de contrôler en plus du moteur principal 22 de ventilateur, un moteur auxiliaire de brosse (non représenté).The classifier deduction block 40 has only two complementary outputs:

• carpet,
• hard and smooth ground.

In this case, all examples of carpets are counterexamples of hard floor, and VICE VERSA. Furthermore, it can be provided to control, in addition to the main fan motor 22, an auxiliary brush motor (not shown).

The classifier deduction block 40 therefore provides two possible outputs which correspond to two complementary classes, indicating the "carpet" state and the "hard floor" state.

For example, the outputs can be:

For the first output: the output level is +1 if the "CARPET" state is detected and is -1 otherwise.

For the second output: the output level is +1 if the "HARD GROUND" state is detected and is -1 otherwise.

Thus, the sum of the output levels of the first and second outputs is zero. The output levels of the classification deduction block 40 can be brought to a processing stage which provides a binary output 41, such as for example the level of this signal 41 is 1 for the "CARPET" state detected, and is 0 for the "HARD GROUND" state detected.

The output 41 of the classifier deduction block 40 is carried on a setpoint block 50 which, by a direct conversion according to the soil, gives a setpoint 51 of the mean pressure amplitude PM which must be imposed at the inlet dust chamber, for proper cleaning of the detected floor.

• si l'état "tapis" a été détecté, alors la consigne est 80 mbar,
• si l'état "sol dur" a été détecté, alors la consigne est 60 mbar.

This instruction 51 is established by simple rules, for example:

• if the "carpet" state has been detected, then the setpoint is 80 mbar,
• if the "hard floor" state has been detected, then the setpoint is 60 mbar.

Applying a pressure amplitude setpoint to the inlet of the dust chamber makes it possible to be sure that each floor to be cleaned is sucked under the most adequate pressure, since the curves in FIG. 3A and B show that the detection elsewhere than at the entrance of the dust chamber is slightly altered.

In addition, according to the invention, this adjustment really only requires a single sensor, which is the inlet pressure sensor 14, in the example described, which allows both the detection of soil and the application of the pressure setpoint. The second sensor 24 relates only to an improvement. As we have seen previously, the vacuum cleaner known from the prior art made it essential to use two different sensors to perform these two functions. According to the invention, the two functions can be performed economically by a single pressure sensor.

Then, according to the invention, the detection, and therefore the setting of the setpoint, is made independently of the commissioning of an electric brush in the nozzle.

This medium pressure amplitude setpoint 51 is transferred to a controller 60 which compares the setpoint signal 51 with the medium pressure amplitude PM 32 existing at this time at the inlet of the dust chamber, and which provides a signal 61 to regulate the electric power of the main motor in such a way that the appropriate pressure setpoint is brought into or maintained at the entrance to the dust chamber.

On the other hand, the output 41 of the classifier deduction block 40 can be brought to a second setpoint block 70, which by a direct conversion as a function of the soil, gives a setpoint 71 of the motor power of an electric brush located in the nozzle.

• si l'état tapis est détecté, alors la consigne est : moteur auxiliaire actionné,
• si l'état sol dur est détecté, alors la consigne est : moteur auxiliaire coupé.

This instruction 71 is established by simple rules such as:

• if the carpet condition is detected, then the setpoint is: auxiliary motor activated,
• if the hard ground condition is detected, then the setpoint is: auxiliary motor off.

In a variant of this implementation, the first setpoint block 50 can be a fuzzy setpoint block.

In fact, the output 41 of the classifier deduction block 40 may not be clear, that is to say may be between 0 and 1, instead of being 0 or 1.

So the fuzzy setpoint block 50 provides pressure values interpolated between 60 and 80 mB in the example cited above.

A fuzzy setpoint block 70 can also be used to supply the brush motor with an intermediate power between all and nothing.

• 1 entrée relative à la pression,
• 1 entrée relative aux sols.

En outre, ce bloc de consigne compact peut être un bloc de consigne floue.In another implementation of the invention, the setpoint blocks 50, 70 can be grouped into a single compact setpoint block having only two inputs:

• 1 pressure input,
• 1 entry relating to the grounds.

In addition, this compact setpoint block can be a fuzzy setpoint block.

• 3 entrées,
• une couche cachée comprenant 0 à 7 neurones, ce nombre dépendant de la complexité des problèmes à traiter,
• 2 sorties pour les signaux calculés qui peuvent être transformées en 1 sortie 41 comme il a été dit précédemment.

In a preferred implementation, the classifier deduction block 40 is a neural network, which in the case where it is sought to detect only the CARPET state and the HARD GROUND state, comprises:

• 3 entries,
• a hidden layer comprising 0 to 7 neurons, this number depending on the complexity of the problems to be treated,
• 2 outputs for the calculated signals which can be transformed into 1 output 41 as mentioned above.

The three inputs of the classifier neural network are then constituted by the three signals of output 31, 32, 33 calculated by the microprocessor 30, and the two outputs are: MAT and HARD FLOOR.

Claims (11)

Vacuum cleaner comprising a vacuum cleaner body provided with an air inlet (11) and an air outlet (21), and a hose provided with a nozzle coupled to the air inlet of the body vacuum cleaner, this vacuum cleaner body including a dust chamber (10) communicating with the air inlet (11), and a housing (20) for a fan (23) driven by an electric motor (22), this housing (20) communicating with the dust chamber (10) and the air outlet (21), this vacuum cleaner further comprising: - A first sensor, called a soil sensor, to supply a signal which is a function of characteristics of the soil surface condition detected by the nozzle during the cleaning operation; - calculation means taking into account the signals provided by this first sensor, to provide a classification signal for the surface condition of the soil, during the cleaning operation, characterized in that the first sensor (14), called the soil sensor, is a pressure sensor which supplies a signal which is a function of the air pressure measured at a first measuring point (15) on the path of the flow of suction air from the vacuum cleaner, this signal having pseudo-periodic oscillations, the maxima (γ) and the minima (ε) correspond for the outward and for the others to the returns of the nozzle on the ground during the cleaning operation, this signal having a difference in amplitude (ΔP), between these maxima and minima, which varies according to the class of the soil cleaned, and in that the calculation means (30.40) determine the class of the cleaned floor, depending on this difference in amplitude (ΔP). Vacuum cleaner according to claim 1, characterized in that the signal from the first pressure sensor known as the soil sensor having a so-called average amplitude (PM), between the amplitudes of the maxima (γ) and minima (ε), which varies according to the class of the cleaned floor, the means of calculation (30.40) determine the class of the soil cleaned jointly as a function of the difference in amplitude (ΔP) between maximum and minimum and of said average amplitude (PM) of the signal from the soil sensor. Vacuum cleaner according to claim 2, characterized in that it comprises setpoint means (50) for determining, as a function of the calculated soil class, a setpoint value (51) for said average amplitude (PM) of the signal of the first pressure sensor (14), so as to adjust the suction pressure appropriately according to the calculated soil class. Vacuum cleaner according to claim 3, characterized in that it comprises control means (60) for comparing the set value (51) with a measurement of the average pressure (32) measured by the first pressure sensor, and for determining a value for adjusting the supply voltage of the fan motor to supply the electrical power which allows the average amplitude of the signal from the first pressure sensor to reach the set value (51). Vacuum cleaner according to one of claims 1 to 4, characterized in that the measuring point (15) of the first pressure sensor (14), said soil sensor, is located at the inlet (11) of the dust chamber (12 ). Vacuum cleaner according to one of claims 1 to 5, characterized in that the calculation means comprise so-called pre-treatment means (30), which receive as input the signal (16) supplied by the first pressure sensor (14), said soil sensor, and which provide as an output, resulting from this pretreatment: - a first signal (32) as a function of said mean value (PM) of the pressure measured on the path of the suction flow by the first pressure sensor; a second signal (31) which is a function of the amplitude difference value (ΔP) between the maximum (γ) and minimum (ε) of the oscillations of the pressure measured on the path of the suction flow by the first pressure sensor ( 14). Vacuum cleaner according to claim 6, characterized in that, the calculation means further comprise a classifier deduction block (40), which receives as input the first and second signals (31,32) coming from said preprocessing means (30), and which provides output corresponding classes, according to predetermined rules, the detection of several different surface states of the soil to be cleaned. Vacuum cleaner according to claim 7, characterized in that the classifier deduction block (40) outputs two classes corresponding to the detection of two different surface states of the floor to be cleaned which are a "CARPET" state and a "SOL" state HARD". Vacuum cleaner according to one of claims 6 to 8, characterized in that it comprises a second pressure sensor (25), for supplying a signal which is a function of the difference of the average air pressures measured between the inlet (PM) and the output (PM ') of the dust chamber (12), and in that the preprocessing means (30) receive this signal and provide in output: - A third signal (33) depending on the average value (PM'-PM) of the difference between the pressures at the inlet and at the outlet of the dust chamber. Vacuum cleaner according to claim 9, characterized in that it further comprises an electric brush arranged in the nozzle and means for adjusting (70) the electric power of the motor of this brush called auxiliary motor depending on the class of the soil calculated. Vacuum cleaner according to claim 10, characterized in that the means for adjusting the power of the auxiliary motor comprise a set point (70) for determining, by direct conversion according to the detected soil class, an adjustment value (71) of the auxiliary motor supply voltage to supply the power which enables the brush placed in the nozzle to be put into service or out of service, depending on the soil class detected.

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