TECHNICAL FIELD

The present invention relates to a method to control the operation of a home appliance for the electromagnetic induction cooking of food and to a corresponding home appliance .

BACKGROUND ART

Known home appliances for the electromagnetic induction cooking of food comprise a cooktop, a plurality of induction units, which are arranged under the cooktop and each of them is provided with respective sensors to detect the presence of a pot on the cooktop above the induction unit, a plurality of control knobs to allow a user to set the level of electrical power supplied to the various induction units and a control board to adjust the electrical power supplied to the induction units based on the power level and to inhibit the electrical power supply to those induction units whose sensors do not detect the presence of any pot.

The more advanced versions of such home appliances have a high number of induction units distributed all over the cooktop divided into cooking areas comprising a certain number of induction units and a touch screen, which allows to control the turning on and the power adjustment of the various cooking areas and to display information concerning the cooking areas where a pot is detected and the relating power levels.

With respect to simple knobs, the advantages of the touch screen, in principle, are an improved aesthetic appearance of the cooktop and a greater versatility. However, while cooking, hands easily get thoroughly dirty, thus soiling the touch screen and compromising the effectiveness of the operation.

DISCLOSURE OF INVENTION

The object of the present invention is to provide a home appliance for the induction cooking of food, which is free from the aforesaid drawbacks and, at the same time, is easy and inexpensive to manufacture.

In accordance with the present invention, it is provided a method to control a home appliance for the electromagnetic induction cooking of food and a home appliance for the electromagnetic induction cooking of food, as defined in the appended independent claims, and preferably in any one of the claims dependent directly or indirectly on the independent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, it is now described a preferred embodiment, purely by way of non-limiting example and with reference to the accompanying drawings, in which:

Figure 1 shows a home appliance for the electromagnetic induction cooking of food according to the teaching of the present invention;

- Figures 2, 3 and 4 show examples of how to use the home appliance of Figure 1; and

- Figures 5 and 6 show two further embodiments of the home appliance of Figure 1.

BEST MODE FOR CARRYING OUT THE INVENTION

In Figure 1, the reference number 1 generally indicates as a whole a home appliance for the electromagnetic induction cooking of food, comprising an upwardly open box-like support 2, a cooktop 3, which is made of ceramic glass and is arranged as a cover above the box-like support 2, a plurality of induction units 4, which are arranged in the box-like support 2 so as to be distributed under the cooktop 3, and a control board 5 of known type to control the turning on, the turning off and the adjustment of the electrical power of the induction units 4. Figure 1 shows only some of the induction units 4 for a better illustrative clarity.

Each induction units 4 is of known type and comprises a coil, known per se and therefore not shown, supplied with AC power generated by the control board 5 to induce the circulation of an eddy current in a metal kitchen utensil, for example a pot 6, placed on the cooktop 3 above the coil so as to heat the pot 6 by means of the Joule effect.

Each induction unit 4 comprises at least one sensor 7 of known type, for example a capacitive or inductive sensor, having the purpose of detecting the presence of the pot 6 above the induction unit 4. The control board 5 collects the signals of the sensors 7 in a format usable by a processing unit to automatically determine the position of the pot 6 on the cooktop 3. Figure 1 shows the sensors 7 only in some induction units 4 for a better illustrative clarity .

According to the present invention, the home appliance 1 comprises movement detection means, in this case a stereoscopic video camera 8, which is mounted at an opening of the cooktop 3 formed along the side 3a of the cooktop 3 which is closest to the user so that the optical detection field of the video camera 8 is oriented upwards to detect the gesture of a human hand which places itself above the cooktop 3 coming from the side 3a, and a processing and control unit 9, which is provided with respective memory means 10 for storing data relating to a plurality of gestures of a hand, communicates with the video camera 8 and with the control board 5, for example through a bus communication system, and is configured to control the control board 5, and therefore the induction units 4, based on the images acquired by the video camera 8 and in particular based on a comparison between the gestures detected by the video camera 8 and the gestures stored in the memory 10, and based on the signals of the sensors 7 acquired through the control board 5. The video camera 8 is of known type and comprises two image sensors spaced apart by a certain distance to detect the depth of the images.

Moreover, the home appliance 1 comprises a weight detection system mechanically coupled to the cooktop 3 to measure the weight of objects arranged on the cooktop 3 and substantially formed by four load cells 11, which are fixed to the box-like support 2 and on which the cooktop 3 is mounted. The load cells 11 are connected to the processing and control unit 9 to send the weight measurements to this latter .

Finally, the home appliance 1 comprises a display, preferably a TFT touch screen 12, which is mounted at an opening of the cooktop 3 and is controlled by the processing and control unit 9 to display information on the pot 6 on the cooktop 3, such as for example its position and its selection by the user based on the signals transmitted by the sensors 7 and on the gestures detected by the video camera 8, information on the adjustment state of the induction units 4 belonging to the area of the cooktop 3 where the pot 6 is located, such as e.g. their being turned on or turned off, the set level of electrical power, the turning on timer or the residual turning on time, and information on the weight of the objects on the cooktop 3.

In more detail, the processing and control unit 9 is programmed with suitable drivers implementing a plurality of parametrised primitive vector functions representing a human hand in a certain number of static and dynamic combinations of stretched out and/or bent fingers and the memory 10 contains, for each of the stored gestures, data concerning a respective combination of values of the parameters of the primitive vector functions. In particular, the memory 10 stores the data concerning at least a selection gesture representing a selection of an area of the cooktop 3, at least an on-off gesture representing the turning on and/or the turning off of at least one induction unit 4 and at least a third adjustment gesture representing an adjustment of the electrical power and/or of the turning on timer of at least one induction unit 4. Moreover, the memory 10 stores data concerning a browsing gesture representing a browsing order on the touch screen 12 of a list of adjustable parameters and/or information concerning the state of the induction units 4 and the cooktop 3, said list comprising, for example, the level of electrical power and/or the turning on timer and/or the residual turning on time of the induction units 4 and/or the weight of the objects on the cooktop 3.

Advantageously, the selection gesture is defined by a hand with at least one stretched out finger, for example with a single stretched out finger or a fully open hand, oriented according to a given direction on a Cartesian plane parallel to the cooktop 3.

Advantageously, the selection gesture is defined by a stationary hand, for a given period of time, with at least one stretched out finger, which is the finger with the most advanced tip among all the fingers of the hand and is represented by a vector oriented according to a given direction on a Cartesian plane parallel to the cooktop 3. This selection gesture cannot be confused with involuntary gestures detectable by the video camera 8 and recognizable by the processing unit 9.

Advantageously, the on-off gesture is defined by a hand that, while being oriented like the selection gesture, mimes the pressing of a button. Figure 2 shows an example of an on-off gesture starting from a selection gesture defined by a hand 13 where the sole index finger 14, whose representative vector is oriented along a direction 15, is stretched out. In particular, the on-off gesture of Figure 2 is defined by the hand 13 miming the pressing of a button according to a direction P with the sole index finger 14.

Advantageously, the adjustment gesture is defined by a hand that, while being oriented like the selection gesture, mimes a clockwise or counterclockwise rotation corresponding to a decrease or to an increase of the electrical power supplied to the induction units 4. Figure 3 shows an example of an adjustment gesture starting from a selection gesture defined by a hand where only the index finger 14 is stretched out and is oriented according to the direction 15. In particular, the adjustment gesture of Figure 3 is defined by the hand 13 miming a rotation R with the sole index finger 14.

Advantageously, the browsing gesture is defined by an open hand miming its own translation to the right or to the left along a direction T preferably transverse to the palm of the hand 13, as in the example shown in Figure 4.

The processing and control unit 9 is of the type comprising a commercial microprocessor, for example an Intel Core i3 processor, and is programmed with a software to carry out the following functional steps.

On the cooktop 3 it is identified a presence area for each pot 6 arranged on the cooktop based on the processing of the signals of the sensors 7 collected and transmitted by the control board 5. The presence area is determined as the area of the cooktop 3 superimposed to the induction units 4, whose sensors 7 detect the presence of a pot 6. Each presence area is then associated with one or more induction units 4 according to the plan dimensions of the pot 6. The touch screen 12 preferably graphically displays the identified presence areas.

The processing and control unit 9 remains on standby until it detects, through the images detected by the video camera 8, one or two human hands that are stationary for a predetermined and programmable time TH, e.g. for 2 seconds, in the detection field of the video camera 8. At the end of the time TH, the processing and control unit 9 tries to recognize the detected gesture of the hand by comparing it with those stored in the memory 10.

If the detected gesture is recognized as a selection gesture, which remains stationary for the time TH, the induction units 4 associated with the presence area matching the selection gesture are selected, then waiting for the detection of a next gesture. With particular reference to the example of Figures 2 and 3, the presence area matching the selection gesture is the area of the cooktop 3 that points at, or better to say, is crossed by the direction 15.

If the detected gesture is recognized as an on-off gesture, the induction units 4 selected with the selection gesture are turned on, if they had been previously turned off, to heat the pot 6, or are turned off, if they had been previously turned on, to stop heating the pot 6.

If the detected gesture is recognized as an adjustment gesture, the electrical power supplied to the selected and turned-on induction units 4 is decreased or increased, based on the direction of rotation of the gesture (Figure 3), thus causing a consequent decrease or increase in the temperature of the pot 6.

The selected presence area and the state of the corresponding induction units 4, i.e. the turned-on or turned-off condition and the level of electrical power is graphically displayed by the touch screen 12.

In accordance with a second embodiment of the present invention, after having turned on the selected induction units 4, the processing and control unit 9 controls the touch screen 12 to display the list of adjustable parameters associated with the aforesaid induction units 4. Therefore, a subsequent adjustment gesture is associated with the parameter that is currently displayed. Preferably, the touch screen 12 displays one parameter at a time, and the first displayed parameter is the level of electrical power. If the detected gesture is recognized as a browsing gesture, the touch screen 12 is ordered to browse through the list and to go to the next parameter.

In accordance with a third embodiment of the present invention, the cooktop 3 is divided into a given number of predetermined macro cooking areas, in which respective presence areas can be identified corresponding to one or more induction units 4 based on the plan dimensions of the pots, and the cooking areas, and therefore also the respective presence areas, are numbered in a predetermined manner, for example from left to right along the width of the cooktop 3, or clockwise or counterclockwise.

Advantageously, in accordance with the third embodiment, a hand miming a number with open fingers defines the selection gesture and the presence area matching the selection gesture is the one whose order number coincides with the number of the selection gesture. Advantageously, in accordance with the third embodiment, the memory 10 stores a turning on gesture defined by a hand rising from a minimum level with respect to the cooktop 3 and a turning off gesture defined by a hand lowering up to said minimum level.

Advantageously, in accordance with the third embodiment, the adjustment gesture is defined by a hand moving vertically with respect to the cooktop between said minimum level and a maximum level with respect to the cooktop 3.

In accordance with a fourth embodiment of the invention shown in Figure 5, in which corresponding elements are indicated with the same reference numbers of Figure 1, the home appliance 1 comprises a horizontal cooker hood 16 of known type and arranged in a known manner at a given distance above the cooktop 3, and the video camera 8 is not mounted in the cooktop 3 but in a lower frame 17 of the hood 16 so that the optical detection field of the camera 8 is oriented downward and then toward the cooktop 3. In particular, the video camera 8 is mounted along the front side 17a of the frame 17, i.e. the side of the frame 17 which is closest to the user standing before the home appliance 1 and therefore is nearest, according to a plan view, to the side 3a of the cooktop 3 to detect the gesture of a human hand which is positioned above the cooktop 3 coming from the side 3a.

In accordance with a fifth embodiment of the invention shown in Figure 6, in which corresponding elements are indicated with the same reference numbers of Figure 1, the home appliance 1 comprises a vertical cooker hood 18 of known type and arranged in a known manner along a side 3b of the cooktop 3 opposite to the side 3a, and the video camera 8 is not mounted in the cooktop 3 but in a front frame 19 of the hood 18 so that the optical detection field of the video camera 8 is oriented obliquely downward and then toward the cooktop 3. In particular, the video camera 8 is mounted along the upper side 19a of the frame 19, i.e. the side of the frame 19 which is farthest from the cooktop 3, with the optical detection field oriented toward the side 3a of the cooktop 3 to detect the gesture of a human hand which is positioned above the cooktop 3 coming from the side 3a.

In accordance with further, not shown, embodiments of the invention, the home appliance 1 comprises, instead of the video camera 8, a miniature radar detection device, transmitting and receiving radar signals at frequencies of a few tens of GHz, arranged alternately in the cooktop 3, in the horizontal cooker hood 16 or in the vertical cooker hood 18. The advantages of the radar detection device if compared to the video camera 8 are its being housed in the structure (cooktop or cooker hood) of the home appliance 1 without having to create a suitable opening and its having a radio detection field angularly much broader than an optical detection field.