WO2010072649A1

WO2010072649A1 - Method for predicting an unbalance, corresponding apparatus and domestic appliance having an apparatus of this type

Info

Publication number: WO2010072649A1
Application number: PCT/EP2009/067427
Authority: WO
Inventors: Steffen Udluft; Peter Blauert
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2008-12-22
Filing date: 2009-12-17
Publication date: 2010-07-01
Also published as: DE102008055092A1; EP2379788B1; EP2379788A1; PL2379788T3

Abstract

The invention relates to a method for predicting an unbalance (E_800p) which occurs in a drum (2) of a domestic appliance for caring for laundry items (7) and is brought about by a distribution of the laundry items (7) in an interior of the drum (2), in which method the prediction is carried out in a lower value range of a rotational speed (n), in particular in a laundry distribution mode, and a value and/or a profile of the unbalance (E_800p) is determined for an upper value range of the rotational speed (n = 800 rpm), in particular for a spin mode, wherein the unbalance (E_800p) is predicted as a function of a measured variable and/or control variable (W), wherein a movement behaviour of an oscillating system of the domestic appliance is characterized by the measured variable and/or control variable (W).

Description

Method for predicting an imbalance, corresponding device and household appliance with such a device

The present invention relates to a method for predicting or occurring in a drum of a household appliance for the care of laundry caused by a distribution of the laundry items in an interior of the drum caused imbalance, wherein the predictions in a lower value range of a speed, in particular in a Laundry distribution operation is performed, and a value and / or a course of the imbalance for an upper value range of the speed, in particular for a centrifugal operation, is determined. Moreover, the present invention relates to a corresponding device for predicting an unbalance or a household appliance with such a device.

Washing machines usually have an electronically controlled drive. Before a transition to a so-called spin operation, a drum is accelerated over a fixed slow laundry distribution operation and an unbalance estimated. In this case, the estimation of the unbalance usually takes place via an engine speed or a loading of the drum. It is always possible to cancel the spin mode or to influence the further spin cycle. For this purpose, methods are known from the prior art in many ways, in which the unbalance is determined from a speed or current profile. In addition, it is known to carry out a correction of the measured value of the imbalance with respect to the laundry load, wherein the laundry load was determined once before or at the beginning of a spin cycle.

A method for predicting an imbalance forming during the spinning of laundry is known from DE 10 2006 032 337 A1. In this method, the amplitude of the movement of a spring-supported tub of a washing machine and the speed of a laundry drum arranged in the tub during a spin cycle is determined. From the amplitude of movement and the drum speed, the change in amplitude over the speed is also determined and the further spin cycle in dependence of this controlled amplitude change controlled. Moreover, in one embodiment of the method disclosed in DE 10 2006 032 337 A1, extrapolation is made from the determined values for the rotational speed, the amplitude and the amplitude change for a possible rotational speed of the further spin cycle.

There is a particular interest in determining the imbalance at the earliest possible time, so that a corresponding correction and a regulation of the spin cycle are ensured. Consequently, the known methods are merely predicting or predicting the imbalance, since it may still change during the further spin cycle. One of the main reasons for this is that, at the time of the prognosis, water bound to the laundry is thrown out over time. As a result, during a spin cycle, even with firmly attached to the drum wall laundry, constantly changing the training imbalance and mass of wet laundry. Both variables significantly influence the amplitude of movement of the tub during the spin cycle.

The object of the present invention is to propose a method and a device or a household appliance with such a device, which ensure an early and reliable predictions of imbalance.

This object is achieved by a method with the features according to claim 1, and by a device having the features according to claim 1 1 and a domestic appliance with the features of claim 13. Advantageous embodiments of the invention are specified in the dependent claims, which can be combined individually or in any combination with the patent claim 1, 1 1 or 13, if such a combination is technically possible and useful. The features of the methods and their advantageous embodiments also define a domestic appliance, which comprises the devices or devices mentioned in the features or the devices or devices designed to carry out the individual method steps.

An inventive method is for predicting or predicting occurring in a drum of a household appliance for the care of laundry, by a distribution of laundry items designed in an interior of the drum caused imbalance. In this method, the prediction is carried out in a lower value range of a rotational speed, in particular in a laundry distribution mode, and a value and / or a progression of the imbalance is determined for an upper value range of the rotational speed, in particular for a centrifugal operation. An essential idea of the invention is that the imbalance is predicted as a function of a measurement and / or control variable, wherein a behavior of movement of a vibration system of the household appliance is characterized by the measurement and / or control variable.

The term household appliance is understood here in particular a washing machine. The term also includes other household appliances for the care of laundry items, such as a dryer or a washer-dryer.

In other words, a basic idea of the present invention is to predict the imbalance on the basis of a measurement and / or control quantity which characterizes a change in weight of wet laundry items during a spin operation or drainage. In particular, an amplitude of the measured and / or control variable, preferably an average amplitude, is determined, wherein the prediction or prediction is preferably dependent on the determined amplitude and the rotational speed is made. Preferably, the lower value range of the rotational speed, in which the prognosis of the imbalance is performed, on the basis of a course of the measured and / or control variable, in particular a curve of the average amplitude, selected in dependence of the rotational speed, and resonances occurring in this course preferably considered. In particular, it can be provided that the measurement of the amplitude of the measured and / or control variable takes place at a speed of about 235 revolutions per minute, whereby the forecast of the imbalance can be improved. Advantageously, it is achieved by the method according to the invention that a very reliable prediction of the imbalance for the upper value range of the rotational speed, in particular for the centrifugal operation, can be made and the imbalance can be determined. In this way, moreover, it is achieved that the spin time can be saved, since an optimum spin cycle or an improved control of the rotational speed can be carried out early. Preferably, a path signal is selected as the measurement and / or control variable, which characterizes a deflection of a tub of the household appliance from a rest position. It can be provided that the path signal is generated by means of a displacement sensor, which is preferably arranged in a spring piston damper of the tub. The term deflection of the tub is understood in particular an amplitude with which the tub swings to a rest position. In particular, an average amplitude of the path signal over at least half a period, in particular over one to three periods, is determined for predicting the imbalance, wherein the average amplitude is preferably determined from a distance between an upper and a lower envelope of the course of the path signal. Preferably, an imbalance mass directly as a function of the deflection of the tub, in particular as a function of the average amplitude of the path signal can be determined. Since the path signal from a value of the rotational speed of about 800 revolutions per minute due to its asymptotic course has virtually no changes in amplitude, it is of particular interest, the imbalance or the deflection of the tub from the rest position for this value of the speed predict. The imbalance is then in particular a measure of the imbalance occurring in the centrifugal operation.

In an embodiment, it can be provided that for predicting the imbalance, a jump behavior of a profile of the measured and / or control variable, in particular of a path signal, is filtered. In particular, jumps of an average of the measured and / or control variable, in particular a sudden behavior of a rest position of the tub, are filtered. In particular, in the case that a spring piston damper is used, the rest position of the tub changes partially leaps and bounds. These jumps are not a consequence of a change in weight of the laundry items or a drainage, but result from a sudden change in position of a friction element within the spring piston damper. These jumps are preferably removed by means of a suitable filter from the course of the measured and / or control variable, in particular the path signal. This ensures that the imbalance can be determined more accurately. Preferably, the measurement and / or control variable, in particular a path signal, from a time of a first complete emptying of a tub of the household appliance is observed.

In one embodiment, it can be provided that, when predicting or predicting the imbalance, a correction value of a dehydration is determined, and the imbalance determined in advance is corrected by the determined correction value, in particular is corrected additively. In particular, during the observation of the measurement and / or control variable, in particular the path signal, a compensation function is determined, by means of which a value of a residual drainage is extrapolated to spin operation. The compensation function preferably has an exponential component. Preferably, the correction value is limited to a value range of about -0.05 mm to about 0.7 mm. In this context, dewatering means, in particular, a dispensing of water and a compression of the items of laundry.

In particular, a possible error of the unbalance forecast can be justified such that at large loadings of the drum an end imbalance by dispensing water and compression of the laundry or by the drainage is smaller, with the rule that the smaller the load of the drum, the weaker this Effect is. For this purpose, the correction of the drainage is particularly advantageous. In addition, when determining the correction value, a loading state of the drum is preferably determined.

In particular, the correction value of the drainage by which the predicted imbalance is corrected, depending on a slope of an average of the measured and / or control variable and / or a sum of squares of a change in the mean of the measured and / or control variable compared to a previous rotation of the drum and / or extrapolated residual drainage.

The method according to the invention is characterized in that it can be used for different laundry loads or it can be adjusted to a current loading situation. A device according to the invention is designed for predicting or forecasting an imbalance occurring in a drum of a domestic appliance for the care of items of laundry caused by a distribution of the items of laundry in an interior space of the drum. The device comprises an imbalance prediction device, by means of which the predictions in a lower value range of a speed, in particular in a laundry distribution operation, feasible, and a value and / or a course of imbalance for an upper value range of the speed, in particular for a spin operation, can be determined. An essential idea is that the imbalance prediction device is designed for predicting the imbalance as a function of a measurement and / or control variable, which is a change in a weight of wet items during a spin operation or a drainage. Preferably, a movement behavior of a vibration system of the household appliance can also be characterized by the measurement and / or control variable.

Advantageous embodiments of the method according to the invention are to be regarded as advantageous embodiments of the device according to the invention. The method steps at the same time define means for performing the method steps, wherein the devices can be comprised by or connected to the device for predicting an imbalance.

Further advantages, features and details of the invention will become apparent from the following description of individual preferred embodiments and with reference to the drawings. Showing:

1 shows a course of a rotational speed and a course of a travel signal of a tub over time.

Fig. 2 shows a comparison of an imbalance forecast at two different loads one

Drum;

Fig. 3 for two different loadings of the drum in each case a course of a

Change a rest position of a tub, a course of a relative

Change of the rest position of the tub and a course of a

Rotation speed; 4 shows an exemplary course of a relative change in the rest position of the tub for explaining a determination of a compensation function;

Fig. 5 is a schematic representation of a washing machine.

The method according to the invention will be explained in more detail below by means of an example. Given is a shown in Fig. 5 domestic appliance for the care of laundry items 7, in this case a washing machine, which has in a housing 1 a suspended on springs 8 tub 3 with a rotatably mounted drum 2 therein. At the tub 3, a balance weight 10 is attached. The drum 2 is driven by a motor 5 via a belt 4. In a damper 6 of the tub 3 a not shown displacement sensor is arranged in the present example, which is able to detect a deflection of the tub 3 from a rest position, and to generate a signal characterizing this deflection. In the present embodiment, the damper is designed as a so-called spring piston damper 6. In the context of the invention, other dampers with an associated displacement sensor, which detects the movement of the damper, can be applied. Hereinafter, this signal is referred to as a path signal. The invention also includes alternative arrangements of the sensor, if such a sensor can detect a movement of the tub 3 relative to the housing 1.

Furthermore, the household appliance comprises a controller 9, which are electrically connected to electrical consumers, such as the motor 5, and measuring devices, such as the displacement sensor. The controller 9 is designed so that the control signals required for operating the household appliance are generated and that the signals detected by the measuring devices can be evaluated by means encompassed by the controller. Such a controller 9 may itself comprise the device for predicting the unbalance caused in the drum 2 or be connected to such a device. Depending on the determined by the device for predicting the unbalance unbalance E ₈ oo _P , the controller 9 generate control signals that affect the further program flow, in particular the centrifugal operation with respect to the control and / or regulation of the speed of Drum 2. Thus, for example, a reduction of a drum speed when exceeding a predetermined unbalance limit for the determined imbalance E ₈ oo _P possible to avoid excessive movements of the tub 3 and excessive mechanical loads.

In the present case, the interest applies to predicting or predicting an imbalance occurring in the drum 2 of the household appliance, caused by a distribution of the laundry items 7 in an interior of the drum 2. The prediction of the imbalance takes place in a lower value range of a rotational speed n of the drum 2, in the present example in a laundry distribution operation of the washing machine. As a result of the prediction, a value or a course of the imbalance for an upper value range of the rotational speed n is determined in the present case. In the present case, the upper value range of the rotational speed n is understood to mean a centrifugal operation of the washing machine, which is carried out during a washing process, in particular after the laundry distribution operation.

To predict the unbalance, the household appliance in the present case comprises a displacement sensor, which is preferably mounted in a spring piston damper 6 of a liquor container 3 arranged in the household appliance. Instead of the displacement sensor may alternatively be provided an acceleration sensor. The displacement sensor has the task to detect a deflection of the tub 3 from a rest position, and then to generate a displacement signal characterizing this deflection. In the present case, the path signal is used for predicting or predicting the imbalance caused by the distribution of the laundry items 7 in the drum 2.

FIG. 1 shows an example course of a rotational speed n (top) as well as a course of a travel signal W indicated underneath and associated with the rotational speed n. As already mentioned, the path signal W corresponds to a deflection of the tub 3 from a rest position. In order to determine the imbalance forecast, an actual amplitude from the path signal W of a last drum revolution is initially calculated in the present case. In this case, an average amplitude of the envelope of the path signal W over at least half a period, ie over at least half a drum rotation, preferably over two to three periods, determined. This average amplitude then represents a measure of the current unbalance. Since the amplitude of the Path signal W has an asymptotic course from a certain speed of about 800 revolutions per minute, in the present case is of particular interest to predict the imbalance occurring at this speed of about 800 revolutions per minute. On the unbalance occurring in the spin mode can then be closed directly from the determined for the speed of 800 revolutions per minute unbalance. The speed selected for this embodiment of 800 revolutions per minute depends on device-specific parameters. The speed is selected to be well above the resonance speed.

Thus, the occurring at the speed of 800 revolutions per minute amplitude of the path signal W as a function of the current amplitude of the path signal W and the current speed n is predicted. In the present case, the following formula applies

Egoo ⁼ E ₈₀₀ (A, nJ = A - E ₈₀₀ (nj,

where A denotes the amplitude of the path signal W. This results in a dependence of the imbalance occurring at the speed of 800 revolutions per minute as follows:

where P ₁ , p ₂ , P ₃ , p ₄ are coefficients to be adjusted herein. Thus, the imbalance E _80O occurring at the speed of 800 revolutions per minute, and thus in the centrifugal operation can be _predicted at any desired speed n from the current amplitude of the path signal W. Considering a profile of the amplitude of the path signal W as a function of the rotational speed n, it can be determined that a first resonance occurs at a rotational speed n of approximately 190 to 200 revolutions per minute. Below the first resonance speed, a large prognosis error can be ascertained, whereby the prediction of the imbalance E ₈ oo drastically improves the prognosis at a speed n of approximately 235 revolutions per minute. FIG. 2 shows a comparison of a predicted imbalance E ₈ oo _p and a measured imbalance E ₈ OOg at a speed of about 800 revolutions per minute. In Fig. 2, the comparison for a large load of the drum 2 and the right for a small loading of the drum 2 is shown on the left. As can be seen, the predicted value of the unbalance E _8O o _p at the large loading of the drum 2 shows a good agreement with the measured value of the imbalance E ₈₀₀₉ . In contrast, the predicted value of the imbalance E _800p shows smaller scattering for smaller loads of the drum 2, but a systematic underestimation of the actual imbalance E _80O9 . This can be seen on the right in FIG. This systematic deviation increases with decreasing load. The systematic error can be justified such that at large loads of the drum 2, the imbalance by dispensing water and compression of the laundry items 7 is smaller, the smaller the load of the drum 2, the weaker this effect. The dispensing of water and compression of the laundry items 7 will be referred to hereinafter as dewatering. With renewed reference to FIG. 1, it can be seen that the path signal W has a vibration about an average value, wherein the mean value corresponds to a rest position of the tub 3. As shown in Fig. 1, this rest position changes with time t, which is due to the dispensing of water and the compression of the laundry items 7 and to the drainage.

In order to take into account the systematic error, a correction of the dewatering of the predicted unbalance is made in the present case. Fig. 3 shows gradients of a change in the rest position M of the tub 3 and curves of the speed n as a function of the number s of the drum revolutions for a small (left) and a large (right) loading of the drum 2 again. The upper curves each show a course of change in the rest position M of the tub 3 versus the number s of drum revolutions, the middle curves each show a course of the relative change in the rest position M of the tub 3. Moreover, the lower curves each represent a curve of the rotational speed n versus the number s of the drum revolutions. Since, in the present example, the spring piston damper 6 is used, the rest position M changes, as shown in FIG. 3, in some cases abruptly. These cracks are not due to a weight change during drainage, but result from a sudden change in position of a friction element within the spring piston damper 6. These jumps are here removed by a filter from the course, as is the case with the course of the relative change in the rest position M in Fig. 3. In Fig. 4 shows an exemplary course of the relative change of the rest position M of the tub 3 as a function of the number s of the drum revolutions is shown. The determination of the correction of the drainage will now be explained in more detail with reference to FIG. 4.

At this point, it should be mentioned that the measurement and the observation of the path signal W begin at a time of a first complete emptying of the tub 3 and the beginning of a laundry dehumidification by means of rotational movement. From this point on, the relative change of the rest position M of the tub 3 is observed. During the observation, a compensation function is determined continuously or sequentially, whereby a residual dewatering is extrapolated to the spin operation on the basis of the compensation function. The compensation function is determined according to the following formula:

Ic ₁ + k ₂ • exp (k ₃ • s).

Here ki, k ₂ , k _{3 designate} parameters which are adapted to the above formula. Moreover, s denotes the number of drum revolutions since the start of laundry dehydration. This compensation function and, moreover, an approximation of the compensation function are shown in FIG. 4 on the basis of the solid or dashed curve.

In the present case, the predicted value of the imbalance E ₈ oo _{P is} corrected additively by the correction value of the drainage. The correction value of the drainage can be limited to a specific interval, for example from -0.05 to 0.7 mm. In the present case, it should be mentioned that the correction value depends on the extrapolated residual drainage, a slope of a linear compensation function (ki + k ₂ s) and a sum of the

Squares of the change in the rest position M compared to the previous drum rotation is. In the present case this connection is represented by a neural

Adapted network with three input nodes and an output node, wherein the neural network, a transfer function and three weights are assigned.

Claims

claims

1. A method for predicting an imbalance in a tub (3) rotatably mounted drum (2) of a household appliance for the care of laundry items (7), by a distribution of the laundry items (7) in an interior of the drum (2) caused imbalance ( E ₈₀ O _p ), in which the prediction is carried out in a lower value range of a rotational speed (n), in particular in a laundry distribution operation, and a value and / or a course of the imbalance (E _8OOp ) for an upper value range of the rotational speed (n = 800 rpm), in particular for a centrifugal operation, is determined, characterized in that the imbalance (E _8OOp ) is _predicted as a function of a measurement and / or control variable (W), the measurement and / or control variable ( W) a change in weight of wet laundry during a spin operation or dewatering is characterized.

2. The method according to claim 1, characterized in that as the measurement and / or control variable, a signal, in particular a path signal (W) is selected, which characterizes as the movement behavior of a vibration system of the household appliance.

3. A method according to claim 2, characterized in that as the measurement and / or control variable, a signal, in particular a path signal (W) is selected, which characterizes as the movement behavior of the oscillating system a deflection of the tub (3) from a rest position.

4. The method according to claim 3, characterized in that the path signal (W) is generated by means of a device encompassed by the domestic displacement sensor, which in particular in a spring piston damper (6) of the tub (3) is arranged.

5. The method according to any one of the preceding claims, characterized in that for predicting the imbalance (E ₈₀ O _p ) a jumping behavior of a course of the measured and / or control variable, in particular a path signal (W), is filtered.

6. The method according to any preceding claim, characterized in that the measurement and / or control variable, in particular a path signal (W), from a time of a first complete emptying of a tub (3) of the household appliance is observed.

7. The method according to any preceding claim, characterized in that when predicting the unbalance (E _8O o _P ) a correction _{value of} a dewatering is determined, and the previously determined unbalance (E ₈₀ O _p ) is corrected by the determined correction value, in particular additive corrected becomes.

8. The method according to claim 7, characterized in that the correction value of the drainage as a function of a change in an average value (M) of the measured and / or control variable (W), in particular as a function of a change in a rest position (M) of a tub (3) , is determined.

9. The method according to any one of claims 7 to 8, characterized in that a

Course of drainage is extrapolated by means of a compensation function until a time of spin operation.

10. The method according to claim 9, characterized in that the compensation function has an exponential component.

11. Device for predicting an imbalance (2) of a domestic appliance for the care of items of laundry (7) occurring in a tub (3) rotatably caused by a distribution of the items of laundry (7) in an interior of the drum (2) ( E _8OOp ), with an imbalance prediction device, by means of which the prediction in a lower value range of a rotational speed (n), in particular in a Wäscheverteilbetrieb, feasible, and a value and / or a course of the imbalance (E _8OOp ) for an upper value range of the rotational speed (n = 800 U / min), in particular for a centrifugal operation, can be determined, characterized in that the imbalance prediction device for predicting the imbalance (E ₈₀ O _p ) is formed as a function of a measuring and / or control variable (W), by which a change in a weight of wet items during a spin operation or a drainage can be characterized.

12. The device according to claim 1 1, characterized in that by the measuring and / or control variable (W) further a movement behavior of a vibration system of the household appliance is characterized.

13. Household appliance, in particular washing machine or washer-dryer, for carrying out the method according to one of claims 1 to 10, characterized in that a device according to claim 1 1 or 12 is included.