Determining imbalance of component rotating about axis of rotation

Abstract

A method and apparatus for determining an imbalance of an object that vibrationally hangs and has a rotating component that is driven in rotation by an electric motor. The sensor continuously records operation data of the rotating part and supplies the operation data to a control device connected with the sensor so as to control the rotating part according to the operation data. The control device determines an imbalance from the operating data. The sensor includes a vibration sensor configured to the object to measure vibration in a plurality of mutually orthogonal dimensions, a current sensor to measure a current flowing through the electric motor, and a rotational speed sensor to measure a rotational speed of the electric motor. The operating data is supplied to a correlation unit associated with the control device, in which correlation unit a learned correlation between the imbalance and the operating data is stored as a function of the training data, by means of which correlation unit the imbalance is determined from the operating data, the training data is measured as operating data for the object under a predetermined imbalance. The method is particularly useful for controlling a dewatering process in a laundry treatment machine.

Description

Technical Field

[0001] The invention relates to a method for determining an imbalance of a vibrating suspended object having a rotating part, wherein the rotating part is driven by means of an electric motor so as to rotate at a determined rotational speed, in that a determined current flows through the electric motor, wherein a sensor continuously records operating data of the rotating part and supplies them to a control device connected to the sensor in order to control the rotating part as a function of the operating data, wherein the control device determines the imbalance from the operating data. The invention also relates to a device for carrying out this method. Background Art

[0002] Document EP2379786B1 discloses a method of the above type, which is implemented in a laundry treatment machine, wherein the vibrating suspended object is a lye container with a drum. According to this document, the deflection of the lye container caused by the imbalance of the rotating drum is measured and the current value of the motor driving the drum and the drum speed value are analyzed with other measured values ​​to determine the imbalance in the drum. The imbalance generated at the corresponding high speed can also be predicted by the measured values ​​obtained earlier and at low speed. For this purpose, a correction function is determined using the data of removing liquid from the laundry items, from which the imbalance at the corresponding high speed is derived.

[0003] Document US2020 / 0010999A1 discloses a method in which machine learning is used to determine an unbalance error in a set laundry treatment machine, wherein the unbalance error is caused by the movement of laundry in the laundry treatment machine. The unbalance error obtained in this way can also be used as an indicator for changing the curve of the laundry dehydration process in the laundry treatment machine. The current flowing through the motor driving the laundry drum and the motor speed are used as measured variables for determining the unbalance error. This unbalance error is determined when the drum rotates slowly so that the laundry pieces move around each other when the drum rotates, and therefore does not conform to the imbalance that is basically stationary over time, such as the imbalance that occurs when the laundry pieces rotate when the drum rotates rapidly and the laundry rests against the inside of the drum. The unbalance error is transmitted to the mobile terminal, in particular, via an electronic network and then displayed to the user. There is no scheme for influencing the laundry treatment machine through a mobile terminal.

[0004] The treatment of laundry in a laundry care machine usually includes a dehydration process, possibly several dehydration processes, in which the majority of the washing liquor, rinsing liquor or water absorbed during the respective washing or rinsing process is spun out and discharged from the laundry items by centrifugal separation at a correspondingly high rotation speed, so that the laundry items can finally be completely dried within a reasonably short time by drying in air or in a special laundry dryer.

[0005] When the laundry items are dehydrated during the dehydration process (wherein the laundry items are centrifuged in a rapidly rotating drum), the laundry items are generally not evenly distributed so that the drum rotating around a predetermined rotation axis is in a state of force and moment balance. On the contrary, when the drum rotates rapidly with the laundry, forces and moments are usually generated on the drum, which cause the drum and the lye container arranged with the drum to vibrate, which is referred to as "unbalance" herein. Therefore, the lye container in the laundry treatment machine is suspended in a vibrating manner by means of spring legs and damping legs. Thus, the vibrations of the lye container are damped during the dehydration process, wherein the damping legs convert the vibration energy into heat. If the dehydration speed is very high and the drum is mostly filled, or if the laundry items in the drum are few but heavy, this damping may not be sufficient. Another issue worth noting is that the vibrations of the lye container are transmitted to the housing of the laundry treatment machine if these vibrations are very obvious or cause additional noise.

[0006] Measures to solve the imbalance problem include reducing the rotation speed of the drum during dehydration or completely canceling the dehydration. However, these measures will result in the dehumidification effect of the clothes not meeting the desired and expected requirements. Therefore, it is desirable to use these measures only to the minimum extent possible.

[0007] The vibrations of a vibrating suspended object are determined in particular by means of a vibration sensor which is fastened to the object or spatially assigned to the object and by which these vibrations are measured directly or indirectly, wherein further data of the object, in particular geometrical dimensions and operating data, are optionally evaluated.

[0008] A method similar to that defined at the outset is needed which can determine the imbalance of a vibrating suspended object as accurately as possible with as little material and data processing effort as possible. Here, it is also possible to predict the expected imbalance during the dewatering process.

[0009] When the method is applied to a vibrating suspended lye container of a laundry machine, in which a drum containing laundry items can rotate, it should be possible to detect the imbalance while determining it as accurately as possible, in particular to take measures to counteract it in a targeted manner and according to its size. Summary of the invention

[0010] In order to achieve the stated object, the present invention provides a method having the features described at the outset and in a corresponding preferred embodiment, and a device for carrying out the method according to a corresponding preferred embodiment.

[0011] The preferred designs of the present invention are given in the optional technical solutions and the following description, and as long as it is technically possible but not explicitly stated in this document, these designs can also be used in combination with each other. As long as it is technically possible but not explicitly stated in this document, the preferred design of the method of the present invention corresponds to the preferred design of the device of the present invention, and vice versa.

[0012] Accordingly, in order to achieve the object, according to the invention, a method for determining the imbalance of an object suspended in vibration and having a rotating part is provided, wherein the rotating part is driven by means of an electric motor so as to rotate at a determined rotational speed, in that a determined current flows through the electric motor, wherein a sensor continuously records operating data of the rotating part and supplies them to a control device connected to the sensor in order to control the rotating part according to the operating data, wherein the control device determines the imbalance from the operating data. In the method, the sensor comprises: a vibration sensor assigned to the object for measuring the vibration of the object in a plurality of mutually orthogonal dimensions; a current sensor for measuring the current flowing through the electric motor; and a rotational speed sensor for measuring the rotational speed of the electric motor, and the operating data are supplied to a correlation unit belonging to the control device, in which a learned correlation between the imbalance and the operating data is stored according to training data, and the imbalance is determined from the operating data by the correlation unit, wherein the training data are measured as operating data for the object at the respectively predetermined imbalance. The sensor can also be used to detect other physical variables that can characterize vibrations, such as force, displacement, strain or their time derivatives.

[0013] According to the invention, a new method for determining the imbalance of an object suspended in vibration and having a rotating part is therefore provided, which method allows the determination of the imbalance with only a low outlay in terms of sensor technology and corresponding signal analysis measures. The use of training data, which empirically contains correlations between imbalance and operating data, has the advantage that the correlations relevant to the imbalance measurement and the parameters describing these correlations do not need to be completely known, nor does it need to limit the imbalance to be described to the imbalance existing at the time of the measurement. Instead, it is also possible to determine future imbalances, i.e. to make predictions.

[0014] There are no special requirements for the positioning of the vibration sensor, so the positioning of the sensor can take into account the given spatial conditions and avoid interference with the environment around the object, which can also achieve the purpose of generating the largest possible measurement signal.

[0015] To obtain the training data, a precisely defined imbalance can be generated in the rotating part of the vibrating suspended object by the targeted introduction of calibration masses, so that operating data can be obtained by observing the corresponding vibrations of the object and the current consumed by the motor and the rotational speed of the rotating part, which are then used to train the relevant unit. It is also helpful to measure the operating data without the introduction of calibration masses, in particular in order to be able to detect and take into account imbalances caused by asymmetries of the rotating part itself. Of course, if the parameters describing the vibration system are known or can be determined, the training data can also be generated by direct calculation based on the predetermined imbalance.

[0016] The vibration, the current and the rotational speed are measured in particular as a time series of corresponding measured values, wherein the time intervals between two values ​​that follow one another are equal to one another and correspond to fractions of a rotation period of the drum, wherein the amplitude and phase of the time series of the drum portion corresponding to the rotation period are determined for each time series. At a rotation frequency of the drum of 1500 revolutions per minute, which corresponds to 25 Hz (this frequency is used in practice for dehydration), such a time period is approximately 2.5 milliseconds, whereby a functional relationship of the vibration with the rotation angle of the drum can be observed. In this case, the rotation period of the drum is 40 milliseconds, so that the preferred value of the time intervals occurring in the time series is 2.5 milliseconds, whereby 16 measurements can be made per one rotation of the drum and the vibration of the lye container can be described accordingly accurately. In the present invention, these time series can be used directly as input values ​​for the relevant units, thus avoiding any preliminary work.

[0017] However, within the scope of the invention, the time series can also be preprocessed, for example to reduce noise influences and thus to improve the accuracy of the imbalance determination. In particular, the time series can be low-pass filtered or band-pass filtered, which can also be supported by using a fast Fourier transform if necessary.

[0018] In a preferred design of the present invention, a regression determined by the training data is implemented in the relevant unit, by which the imbalance is determined by the operating data. In machine learning, "regression" refers to any model that maps a given input variable to a continuous real number as an output variable, which is different from "classification" that maps the corresponding input variable to a discrete category. In regression, a distinction is made between linear methods (such as linear regression) and nonlinear methods (such as neural networks), while in this example, both linear and nonlinear methods can be considered.

[0019] In a first preferred design of the invention, the correlation unit is a neural network trained with training data, in which the regression is implemented.

[0020] In a second preferred design of the invention, the regression implemented in the correlation unit is a PLS regression.

[0021] In a further preferred embodiment of the invention, the unbalance is determined for a rotational speed which is greater than the rotational speed measured when the unbalance is determined. In this case, the invention can be used to predict the unbalance which will occur in a given case after the unbalance is determined, for example if the rotational speed increases over a predetermined time or if the rotational speed is different from the measured rotational speed, in particular higher. In particular, the rotational speed at which the unbalance is determined is intended to be realized in the future within the framework of a predetermined rotational speed curve.

[0022] It is further preferred that the imbalance is influenced by the distribution of the filling in the rotating part, wherein the distribution of the filling can be changed by rotating the rotating part at a speed lower than a fixed speed, in which method the imbalance determined at the predetermined speed is compared with a first threshold value, and if the determined imbalance is greater than the first threshold value, the speed of the rotating part is reduced to a value lower than the fixed speed at a predetermined time interval, then increased to the predetermined speed again, and then the imbalance is re-determined. This is particularly the case if the vibrating suspended object is a lye container in a laundry treatment machine and the rotating part is a drum with the laundry items. When the laundry items are centrifuged to remove the treatment liquid such as washing lye, rinsing lye or water, the drum with the laundry items rotates rapidly at a speed higher than the fixed speed, from which the laundry items begin to rest against the inside of the drum and thus cause an imbalance. If the determination result shows that the imbalance exceeds a given first threshold value at a speed given during the measurement or at a speed higher than this speed but not yet reached, a redistribution of the laundry items in the drum can be achieved by slowing down the rotation to below the fixed speed, thereby resulting in a different imbalance, in particular a lower imbalance.

[0023] In another preferred embodiment of the invention, the rotating part is supported in a bearing in the object, and the load on the bearing due to the imbalance is determined by the determined imbalance. Thus, the load on the bearing can be directly determined, whereby the speed can be adjusted to avoid excessive load on the bearing.

[0024] In another preferred design of the present invention, the rotating component rotates at a predetermined nominal speed, and the determination of the imbalance is performed cyclically, wherein each determined imbalance is compared with a second threshold value, and if the imbalance is greater than the second threshold value, the rotation speed of the rotating component is reduced to a lower nominal speed that is less than the predetermined nominal speed. Further preferably, the rotating component rotates at the lower nominal speed, wherein each determined imbalance is compared with the second threshold value, and if the imbalance is less than the second threshold value, the rotation speed of the rotating component is increased to a speed that is greater than the lower nominal speed and less than or equal to the predetermined nominal speed. In this way, the rotation speed can be controlled according to the imbalance determined periodically and repeatedly.

[0025] In another preferred embodiment of the invention, the vibration sensor measures vibrations in three mutually orthogonal dimensions. This opens up the use of the invention as a "3D sensor" that can measure vibrations and, in particular, the accelerations generated thereby.

[0026] According to the present invention, a device for implementing the method of the present invention or its design is also disclosed, which includes: a rotating part rotating in a vibrating suspended object; an electric motor for driving the rotating part to rotate at a determined rotational speed, in which a determined current flows through the electric motor; and a sensor for continuously recording operating data of the rotating part; a control device, which is connected to the sensor, for controlling the rotating part according to the operating data and for determining imbalance from the operating data.

[0027] In a preferred embodiment of the invention, the object is suspended in the housing by means of spring legs and damping legs. Further preferably, the device is designed as a laundry treatment machine, wherein the object is a lye container and the rotating part is a drum arranged in the lye container for receiving a filling formed by laundry items. Even further preferably, the device is designed for carrying out the method to determine the imbalance during a dehydration process, during which treatment liquid, in particular washing lye, rinsing lye or water, absorbed by the laundry is removed from the laundry items by centrifugation.

[0028] In principle, the invention can be applied to any type of laundry processing machine, especially since the application of the invention requires little effort. Thus, in addition to conventional washing machines, simple laundry dehydrators and washing and drying machines are also conceivable. The orientation of the drum axis of rotation in space is not important. As described in detail below, the axis of rotation can be essentially horizontal, but can also be vertical or at any angle to the vertical. In particular, the drum is cylindrically shaped, with its shell or side (Mantel) extending parallel to the axis of rotation, a rear wall connected to the drive shaft at the rear end, and a front end bottom designed as a ring, through which the interior of the drum can be accessed for inserting and removing the laundry items.

[0029] In the laundry treatment machine designed according to the invention, the system with the lye container and the drum, which is designed to vibrate, has in particular a resonant frequency, and the highest rotational frequency corresponding to the highest rotational speed is greater than the resonant frequency. This has the advantage that any vibrations can be effectively damped. The resonant frequency is determined in particular by the vibration suspension of the lye container on spring legs and damping legs in the housing. Due to the imbalance, particularly large vibrations are to be expected here. Therefore, when accelerating the drum to the desired rotational speed, the rotational speed corresponding to the resonant frequency should be passed as quickly as possible.

[0030] Preferably, if the load caused by the imbalance exceeds a predetermined second threshold value, the rotation of the drum is stopped and restarted. The advantage of restarting the rotation is that the laundry items to be spun can be redistributed, thereby reducing the imbalance that was initially present. Another advantage is that the rotation frequency of the drum is below the resonance frequency when the imbalance is first determined. In this way, the imbalance is detected early in the spin process and the time loss caused by restarting is kept small. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0032] Figure 1 A schematic side view showing an example of a laundry treatment machine arranged according to the invention, having a vibrating suspended body in which a rotating part is arranged;

[0033] Figure 2 A simplified front view of the same laundry machine is shown;

[0034] Figure 3 a graph showing the results of an imbalance test determined using the method of the present invention; and

[0035] Figure 4 A diagram showing a dehydration process of a laundry machine arranged according to the present invention. DETAILED DESCRIPTION

[0036] Figure 1 and Figure 2 Two mutually orthogonal cross-sections: Figure 1 is a YZ plane view (i.e. viewed from one side) and Figure 2 The figure shows a schematic embodiment of a laundry treatment machine 1 in an XY plane view (i.e., viewed from the front), which is designed as an example of an apparatus for implementing the method of the present invention. The laundry treatment machine 1 has a housing 2 and a lye container 3 arranged in the housing, which is used to receive a treatment liquid, in particular a washing and rinsing lye for fabrics.

[0037] The laundry treatment machine 1 is designed as a washing machine 1. A drum 4 rotatable about a rotation axis 5 is arranged in a lye container 3. The rotation axis 5 is Figure 1 Shown as a dot-dashed line in Figure 2 , are shown as "X" in the figure, and are surrounded by arc-shaped arrows as rotation symbols. The drum 4 contains laundry items 6 treated with a treatment liquid. A roughly cylindrical shell (or side) extends from the front end to the rear end of the alkali liquid container, and a gap is formed between the shell and the drum. The drum is closed by a roughly circular end side bottom near the front end and by a roughly circular rear wall near the rear end. A leather cup 7 (in the middle) made of a flexible material such as EPDM Figure 1The lye container 3 is connected to the housing 2 in a liquid-tight manner by a door 8 (indicated by dashed lines in the figure), and during operation of the laundry treatment machine 1, the lye container 3 is closed to the outside by a door 8 in a liquid-tight manner. For rotation, the drum 4 is driven by a drive shaft 9 (which is guided through the lye container 3 in a sealed manner at a bearing 10), a first pulley 11, a drive belt 12, a second pulley 13 and a motor 14, which is fastened to the lye container 3. Systems for supplying, heating and draining process liquids (such as water and detergent or rinse agent) belonging to the laundry treatment machine 1 are not shown in the figure, because these systems are not absolutely necessary for describing the method according to the invention.

[0038] Figure 1 The current sensor 15 for measuring the current flowing through the motor 14 and the speed sensor 16 for measuring the speed of the motor 14 are shown only schematically as pipelines. There are no special requirements for the design of these sensors 15 and 16, and any suitable known sensors can be used. The current sensor 15 can be a resistor placed in a pipeline (through which the current flows to the motor 14), through which a voltage proportional to the current is measured, wherein the resistor can be integrated in the control device 20. The speed sensor 16 can be a coil located in the motor 14, and whenever the motor 14 rotates the drum 4, a voltage is induced in the coil, and the voltage is supplied to the control device 20 to determine the speed.

[0039] The lye container 3 is suspended in a vibrating manner in the housing 2 by means of spring legs 17 and damping legs 18. In particular, due to uneven distribution of the laundry items 6 in the drum 4 and in particular when the drum 4 rotates rapidly to dehumidify the laundry items 6 by centrifugation or spin drying, a large imbalance may occur, which leads to vibrations of the lye container 3, which are captured by the spring legs 17 and the damping legs 18, wherein the energy of these vibrations is converted into friction heat in the damping legs 18 and released to the environment.

[0040] A 3D sensor 19 is provided for measuring vibrations of the lye container 3 in three mutually orthogonal dimensions, wherein the measured values ​​are supplied to the control device 20. In the present example, the 3D sensor is mounted on the upper part of the lye container 3, but this is not a requirement. In principle, the 3D sensor can be mounted at any position on the lye container 3, even at a position far from the lye container 3, wherein the 3D sensor 19 is preferably mounted at a position of the lye container 3 at which vibrations are particularly large due to possible imbalances, in order to keep measurement errors low and to obtain a particularly good signal-to-noise ratio.

[0041] The determination of the vibrations of the lye container 3 can be used to observe these vibrations and also to influence them by influencing the elasticity and damping properties of the spring legs 17 and the damping legs 18 in a suitable manner or by controlling or cancelling and restarting a process in which the laundry items 6 are handled while causing an imbalance as a function of these vibrations.

[0042] The lye container 3 and / or the spring leg 17 and the damping leg 18 may include further sensors in the form of strain gauges (not shown) for detecting deformations of the lye container 3 caused by vibrations and / or forces introduced via the spring leg 17 and the damping leg 18. Force sensors (not shown) may also be arranged as further sensors at the support points of the spring leg 17 and the damping leg 18, which are designed, for example, as measuring washers.

[0043] The control device 20 is used to control the laundry machine 1 , in particular the motor 14 and other systems (not shown), and to record and analyze the above-mentioned measured values.

[0044] In this method for determining the imbalance of a vibrating suspended object 3 (i.e., a lye container 3) having a rotating part 4 (i.e., a drum 4), the rotating part 4 is driven by means of an electric motor 14 so as to rotate at a determined rotational speed, in that a determined current flows through the electric motor 14, wherein sensors 15, 16, 19 (i.e., a current sensor 15, a rotational speed sensor 16, and a 3D sensor 19) continuously record operating data of the rotating part 4 and supply these data to a control device 20 connected to the sensors 15, 16, 19 and / or to other sensors as appropriate, in order to control the rotating part 4 as a function of the operating data, wherein the control device 20 determines the imbalance from the operating data. In this case, the operating data are supplied to a correlation unit 21, in which correlations between the imbalance and the operating data, which have been learned based on training data, which have been measured as operating data of the object 3 at respectively predetermined imbalances, are stored, and the imbalance is determined from the operating data by the correlation unit 21.

[0045] In order to obtain the training data, a precisely defined imbalance can be generated in the rotating part 4 of the vibrating suspended object by the targeted introduction of a calibration mass 21 - without filling the object 6 with clothing items - so that by observing the corresponding vibrations of the object 3 and the current consumed by the motor 14 and the rotational speed of the rotating part 4, operating data are obtained, which are then used to train the correlation unit 21. It is also helpful to measure the operating data without the introduction of a calibration mass 21, which is mainly to be able to detect and take into account the imbalance caused by the asymmetry of the rotating part 4 itself. Of course, if the parameters describing the vibration system 3, 4, 17, 18 are known or can be determined, the training data can also be generated by directly calculating the operating data according to the predetermined imbalance.

[0046] In the correlation unit 21, a regression determined from the training data is performed, by which the imbalance is determined from the operating data. In the context of machine learning, "regression" refers to any model that maps given input variables to continuous real numbers as output variables, which is different from "classification" that maps the corresponding input variables to discrete categories. Regression is divided into linear methods (linear regression) and nonlinear methods (such as neural networks), and in this case, both linear and nonlinear methods can be considered.

[0047] In a first preferred design of the invention, the correlation unit is a neural network trained with training data, in which the regression is implemented.

[0048] In a second preferred design of the invention, the regression implemented in the correlation unit is a PLS regression.

[0049] Alternatively, the correlation unit 21 is a neural network trained with training data, in which a regression is implemented, or a PLS regression determined on the basis of the training data is implemented in the correlation unit 21 .

[0050] The method can be used not only to measure the imbalance existing at the measurement time point, but also to predict the imbalance at a time point after the measurement, i.e. the future imbalance. In this case, use is made of the fact that the correlation between the operating data and the imbalance is stored in the correlation unit 21 only in the form of a correlation and not in the form of a mathematical function in the narrow sense. In contrast to such functions, correlations can also be formed between data that do not apply to a single time point, provided, of course, that the characteristics of the system are always the same between the measurement time point and the time point applicable to the specific imbalance. In this case, it is particularly desirable to determine the imbalance for a rotational speed that is greater than the rotational speed measured when determining the imbalance, so that a prediction of the imbalance can be made. Reference will be made below to Figure 4 Explain the dehydration process in which this prediction comes into play.

[0051] In the laundry treatment machine 1, the imbalance is affected by the distribution of the laundry pieces forming the filling 6 in the rotating part 4, wherein the distribution of the filling 6 can be changed by rotating the rotating part 4 at a rotation speed lower than a fixed rotation speed at which the filling is substantially in close contact with the inner wall of the rotating part 4. Therefore, the imbalance determined at a predetermined rotation speed is compared with a first threshold value, and if the determined imbalance is greater than the first threshold value, the rotation speed of the rotating part 4 is reduced to a value lower than the fixed rotation speed within a predetermined time interval, and then increased again to the predetermined rotation speed, and then the imbalance is re-determined.

[0052] In the method, for the bearing 10 in which the rotating component 4 is supported in the object 3 , the load to which the bearing 10 is subjected due to the imbalance is determined based on the determined imbalance.

[0053] In particular, during the dehydration process of the laundry machine 1, if the rotating part 4 rotates at a predetermined nominal speed and the imbalance is periodically determined, the imbalance determined each time is compared with the second threshold value, and if the imbalance is greater than the second threshold value, the rotation speed of the rotating part 4 is reduced to a lower nominal speed lower than the predetermined nominal speed. This avoids the load caused by excessive imbalance.

[0054] If the rotating component 4 rotates at the lower nominal speed, each determined imbalance is compared with a second threshold value, and if the imbalance is less than the second threshold value, the rotation speed of the rotating component 4 is increased to a speed greater than the lower nominal speed and less than or equal to the predetermined nominal speed. In this way, the efficiency of the dehydration process can be improved by checking and, if necessary, canceling the speed reduction caused by excessive imbalance.

[0055] The drum 4, which is suspended in vibration on the spring legs 17 and the damping legs 18, has a resonant frequency (or multiple resonant frequencies) in its vibrations, wherein the highest rotational frequency provided in the method is greater than the resonant frequency. This has the advantage of effectively damping possible vibrations. However, at the resonant frequency, the vibrations caused by the imbalance are particularly large. Therefore, when accelerating the drum to the required rotational frequency and when braking after the dehydration process is completed, the rotational frequency corresponding to the resonant frequency should be passed as quickly as possible.

[0056] In particular, at the beginning of the dehydration process, if the load falls below a predetermined second threshold value, it is necessary to stop the rotation of the drum 4 and restart it. This occurs if the rotation frequency of the drum 4 falls below the resonance frequency when the imbalance is detected. In this way, the imbalance is detected early in the dehydration process and the time loss caused by the restart is kept small.

[0057] Figure 3 The diagram in shows how accurately the novel method described herein determines the imbalance from the correlation of the training data. The figure shows the results of a test ("spinning operation"), in which the imbalance determined in the drum 4 of the laundry machine 1 arranged as described above was caused by installing the calibration mass 21. The abscissa in the diagram marked "measured imbalance" represents the absolute value of the imbalance calculated or predicted based on the corresponding installed calibration mass, and the ordinate marked "predicted imbalance" (or determined imbalance) represents the imbalance determined by the correlation unit 21. Each black circle represents a test.

[0058] from Figure 3It can be seen that the test data are distributed quite closely around the diagonal line in the diagram, which clearly shows the accuracy of the correlation-based test method. Deviations of the test data from the above-mentioned diagonal line can be explained in particular by the fact that not only the absolute amount of the imbalance has an influence on the vibration of the lye container 3, but also the position or distribution of the imbalance along the axis of rotation and, if necessary, the distribution of the imbalance around the axis of rotation 5. In addition, there may be other influencing variables that are not taken into account in the present model. Therefore, the distribution of the test data closely around the above-mentioned diagonal line shows that the method can detect existing imbalances with very small errors and is therefore particularly suitable as a basis for predicting and avoiding imbalances.

[0059] Figure 4 The diagram in shows a typical dehydration process of a correspondingly configured laundry treatment machine 1. The abscissa of the diagram represents time ("time"), and the ordinate represents the rotational speed of the drum 4 with the laundry items 6. The ordinate also indicates the rotational speed below which the vibration system resonates (marked as "subcritical"), the rotational speed that causes such resonance (marked as "critical range" or "resonance"), and the rotational speed above which resonance occurs (marked as "overcritical"), wherein the position of the "resonance" range needs to be determined empirically if necessary and also depends on the laundry items 6 loaded in the drum 4.

[0060] Figure 4 The dehydration process shown begins with the loading of the drum 4 with the laundry items 6, initially starting at a subcritical rotational speed and then accelerating to a rotational speed slightly below the critical range. It is also possible to repeatedly accelerate to a rotational speed slightly above the critical range in order to obtain, at least briefly, a strong vibration of the lye container 3, so that a possible imbalance can be determined as accurately as possible. If the imbalance determined in this way is too high, the drum 4 can be completely stopped in order to restart the process and work on reducing the imbalance by redistributing the laundry items 6 in the drum. Finally, when the rotational speed of the drum is alternately above and below the critical range, a prediction of the imbalance at the highest rotational speed is determined and the dehydration process is continued by further accelerating the drum 4 to the highest rotational speed, taking this prediction into account. In this case, the prediction ensures that the imbalance that occurs at a rotational speed equal to or slightly below the highest rotational speed is not so large that damage to the laundry treatment machine 1 is expected. By further determining the imbalance during the dehydration process, the rotational speed of the drum 4 can be reduced as necessary to maintain a predetermined limit or threshold value for the imbalance.

[0061] By accurately knowing the imbalance that occurs during the dehydration process, on the one hand, it is possible to set the components used to manufacture the clothing care machine 1 to the maximum imbalance that can be monitored by the method described herein, thereby reducing the cost of these components. On the other hand, it is also possible for the user of the clothing care machine 1 to individually predetermine the threshold value of the imbalance that occurs during the dehydration process through the operating area on the clothing care machine 1 or the application on the mobile terminal, so that the user can take into account unfavorable installation of the clothing care machine 1, affecting the maximum noise of the clothing care machine 1 or its expected energy consumption. In any case, avoiding unnecessary dehydration starts and premature stops and restarts for redistribution of clothing items 6 helps to improve the user-friendliness of the clothing treatment machine 1 by completing the clothing treatment process more quickly and saving unnecessary start-up energy.

[0062] According to the invention, therefore, a new method for determining the imbalance of an object 3 which is suspended in vibration and has a rotating part 4 is provided, which allows the imbalance to be determined with little outlay in terms of sensor technology and measures for evaluating the corresponding signals.

[0063] List of reference numerals:

[0064] 1 Washing machine

[0065] 2 Shell

[0066] 3. Vibrate hanging objects, lye containers

[0067] 4 rollers

[0068] 5 Rotation Axes

[0069] 6 Fillings, clothing items

[0070] 7 Leather Bowl

[0071] 8 doors

[0072] 9 Drive shaft

[0073] 10 Bearings

[0074] 11First pulley

[0075] 12 Drive belt

[0076] 13 Second pulley

[0077] 14 Motor

[0078] 15. Current sensor

[0079] 16 Speed ​​sensor

[0080] 17 Spring Legs

[0081] 18 Damping Leg

[0082] 19 3D Sensor

[0083] 20 Control device

[0084] 21 Related Units

[0085] 22 Calibration quality.

Claims

1. A method for determining an unbalance of an object (3) which is suspended in vibration and has a rotating part (4), wherein the rotating part (4) is driven by means of an electric motor (14) so ​​as to rotate at a determined rotational speed, in that a determined current flows through the electric motor (14), wherein sensors (15, 16, 19) continuously record operating data of the rotating part (4) and supply them to a control device (20) connected to the sensors (15, 16, 19) in order to control the rotating part (4) as a function of the operating data, wherein the control device (20) determines the unbalance from the operating data, characterized in that The sensors (15, 16, 19) include: a vibration sensor (19) assigned to the object (3) for measuring the vibration of the object (3) in multiple mutually orthogonal dimensions; a current sensor (15) for measuring the current flowing through the electric motor (14); and a rotation speed sensor (16) for measuring the rotation speed of the electric motor (14); The operating data are supplied to a correlation unit (21) assigned to the control device (20), in which a learned correlation between the imbalance and the operating data is stored based on training data, which were measured as operating data for the object (3) at respectively predetermined imbalances, and the imbalance is determined from the operating data by the correlation unit (21).

2. The method according to claim 1, wherein: In the correlation unit (21), a regression is carried out which is determined from the training data, by which the imbalance is determined from the operating data.

3. The method according to claim 2, wherein: The correlation unit (21) is a neural network trained with training data.

4. The method according to claim 2, wherein: The regression is a PLS regression.

5. The method according to any one of the preceding claims, wherein: The unbalance is determined for a rotational speed that is greater than the rotational speed measured during the determination of the unbalance.

6. The method according to claim 5, wherein: The imbalance is influenced by the distribution of a filler (6) in the rotating component (4), wherein the distribution of the filler (6) can be changed by rotating the rotating component (4) at a speed lower than a fixed speed. In the method, the imbalance determined at a predetermined speed is compared with a first threshold value. If the determined imbalance is greater than the first threshold value, the speed of the rotating component (4) is reduced to a value below the fixed speed for a predetermined time interval and then increased again to the predetermined speed, and then the imbalance is redetermined.

7. The method according to any one of claims 5 and 6, wherein: The rotating component (4) is supported in the object (3) in a bearing (10), wherein the load to which the bearing (10) is subjected due to the imbalance is determined from the determined imbalance.

8. The method according to any one of claims 5 to 7, wherein: The rotating component (4) rotates at a predetermined nominal speed, wherein the determination of the imbalance is performed cyclically, wherein each determined imbalance is compared with a second threshold value, and if the imbalance is greater than the second threshold value, the rotation speed of the rotating component (4) is reduced to a lower nominal speed that is less than the predetermined nominal speed.

9. The method according to claim 8, wherein: The rotating component (4) rotates at the lower nominal speed, wherein each determined imbalance is compared with a second threshold value, and if the imbalance is less than the second threshold value, the rotation speed of the rotating component (4) is increased to a rotation speed greater than the lower nominal speed and less than or equal to the predetermined nominal speed.

10. The method according to any of the preceding claims, wherein: The vibration sensor (19) measures vibrations in three mutually orthogonal dimensions.

11. An apparatus (1) for implementing the method according to any one of the preceding claims, comprising: a rotating member (4) which rotates in the vibrating suspended object (3); an electric motor (14) for driving the rotating component to rotate at a determined rotational speed, wherein a determined current flows through the electric motor (14); and sensors (15, 16, 19) for continuously recording operating data of the rotating component (4); and a control device (20) connected to the sensors (15, 16, 26) for controlling the rotating component (4) according to the operating data and for determining the imbalance from the operating data.

12. The device (1) according to claim 11, wherein: The object (3) is suspended in the housing (2) by means of a spring leg (17) and a damping leg (18).

13. The device (1) according to claim 12, which is configured as a laundry treatment machine (1), wherein the object (3) is a lye container (3), and wherein the rotating part (4) is a drum (4) arranged in the lye container for receiving a filling (6) formed by laundry items.

14. The device (1) according to claim 13, which is designed to carry out the method for determining an imbalance during a spin cycle, in which process liquid, in particular wash liquor, rinse liquor or water, absorbed by the laundry items is removed from the laundry items by centrifugation.

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