[0001] The invention relates to a laundry treatment machine. Furthermore, the invention
relates to a method to operate a laundry treatment machine. For example, the laundry
treatment machine is a washing machine or a drying machine or a combined washing and
drying machine.
[0002] The washing unit of a laundry treatment machine is suspended to the cabinet by a
set of springs and dampers. This mechanical system is adjusted to have a resonance
frequency at a relatively low angular speed. During the spinning phase, the angular
speed of the drum has to cross this resonance region without interference between
the tub and the cabinet. Due to an increase of the drum size and a loading capacity
of the laundry treatment machine the available space between the tub and the cabinet
decreased. As a consequence, a precise estimation of an unbalance of the load is required
in order to avoid a mechanical impact between the tub and the cabinet when the resonance
region is crossed. The unbalance estimation has to be performed before the resonance
region is crossed.
[0003] EP 1736 589 A2 discloses a washing machine with a measurement device for detecting an unbalance
of the drum. The washing machine comprises two acceleration sensors which are arranged
in a twelve o'clock position at a front side and a rear side of the drum. Furthermore,
the washing machine comprises an angular speed sensor with a detector which detects
marks at a rotating body. A controller of the washing machine determines the position
and the magnitude of the unbalance from the measurement values.
[0004] It is an object of the present invention to provide a laundry treatment machine which
enables to estimate a behaviour of a load in an easy, reliable and accurate manner.
[0005] This object is achieved by a laundry treatment machine with the features of claim
1. In order to get a reliable and accurate estimation of the load behaviour it is
essential that the at least one unbalance sensor and/or the at least one position
sensor provides a measurement signal with a high signal quality. An increased signal
quality results in an increased estimation accuracy. Therefore, it is important that
disturbances are reduced in each measurement signal and a high signal-to-noise ratio
is achieved.
[0006] The at least one unbalance sensor is arranged at a position such that for the angle
α applies: 0° < α < 90°, in particular 15° ≤ α ≤ 75°, and in particular 30° ≤ α ≤
60°. For each unbalance sensor the angle α is defined in a projection plane which
runs perpendicular to the axis of rotation. In theory, the signal quality of the measurement
signal of the at least one unbalance sensor would be best at an angle of α = 90°,
since at this angle an unbalanced load generates a maximum torque. However, the suspension
system changes this angular position of high signal quality. Furthermore, an angular
position of α = 90° results in a decreased drum size or in an increased risk of a
mechanical impact during operation of the laundry treatment machine. Since 0° < α
< 90° applies, the at least one unbalance sensor provides a good signal quality without
the above described disadvantages.
[0007] Preferably, the rotational axis defines a horizontal plane and the at least one unbalance
sensor is arranged above and/or below this horizontal plane. Preferably, the at least
one unbalance sensor is arranged between a 0 o'clock position and a 3 o'clock position
and/or between a 0 o'clock position and a 9 o'clock position and/or between a 6 o'clock
position and a 3 o'clock position and/or between a 6 o'clock position and a 9 o'clock
position. Preferably, the at least one unbalance sensor is arranged at a tub of the
laundry treatment machine. Preferably, the at least one unbalance sensor is at least
one of an accelerometer sensor and an optical sensor.
[0008] The signal quality of the measurement signal of the at least one position sensor
is increased, because the at least one part to be detected is arranged directly at
the drum. Preferably, the laundry treatment machine has exactly one angular position
sensor. Preferably, the at least one part to be detected is arranged at a rear side
of the drum. Preferably, the at least one position sensor comprises a number of k
parts to be detected wherein 1 ≤ k ≤ 32, in particular 2 ≤ k ≤ 16, and in particular
4 ≤ k ≤ 8. The parts to be detected are attached at the drum at equal angular distances.
The detector is arranged at a tub and/or at a cabinet of the laundry treatment machine.
The attachment of the at least one part to be detected directly at the drum results
in a decreased amount of mechanical disturbances and in an increased signal quality.
The at least one position sensor enables an easy assembly.
[0009] Preferably, the at least one position sensor is a once per revolution sensor with
a detector and exactly one part to be detected. The exactly one part is mounted at
a defined angular position at the drum such that the at least one position sensor
provides an absolute angular position of the drum. Preferably, the detector is designed
as Hall sensor or reed switch. Preferably, the at least one part to be detected is
designed as a magnet.
[0010] The at least one unbalance sensor and the at least one position sensor can be used
independently of each other or in combination and result both in an increase of signal
quality such that the laundry treatment machine enables an estimation of the load
behaviour in any easy, reliable and accurate manner.
[0011] Preferably, the laundry treatment machine comprises a washing unit which is suspended
to a cabinet by means of a suspension system. The suspension system comprises springs
and dampers. A tub of the washing unit is suspended to the cabinet by means of the
springs and the dampers. The drum is arranged within the tub. The drive motor may
be connected to the drum directly or via a belt drive.
[0012] A laundry treatment machine according to claim 2 ensures an easy, reliable and accurate
estimation of the load behaviour. A base of the laundry treatment machine defines
a base plane. The horizontal plane runs in parallel to the base plane. Preferably,
the at least one unbalance sensor is arranged between a 0 o'clock position and a 3
o'clock position and/or between a 0 o'clock position and a 9 o'clock position.
[0013] A laundry treatment machine according to claim 3 ensures an easy, reliable and accurate
estimation of the load behaviour. The laundry treatment machine has a centre of gravity.
The centre of gravity defines a vertical plane which runs perpendicular to the axis
of rotation. This vertical plane defines a front side and a rear side. Preferably,
the first unbalance sensor and the second unbalance sensor are arranged at different
sides of this vertical plane, namely at the front side and at the rear side. Preferably,
the first unbalance sensor and the second unbalance sensor have a distance from each
other in an axial direction. The unbalance sensors enable to estimate the behaviour
of load which is unequally distributed in a direction parallel to the axis of rotation.
The unbalance sensors may have equal or different measuring principles.
[0014] A laundry treatment machine according to claim 4 ensures an easy, reliable and accurate
estimation of the load behaviour. The artificial neural network has an input layer,
at least one hidden layer and an output layer. Preferably, the artificial neural network
has a number M of hidden layers, wherein 1 ≤ M ≤ 5, in particular 2 ≤ M ≤ 4. Preferably,
the artificial neural network is designed as feedforward neural network.
[0015] A laundry treatment machine according to claim 5 ensures an easy, reliable and accurate
estimation of the load behaviour. An input layer of the artificial neural network
provides at least one signal input. Preferably, the at least one signal input is connected
to a signal output of the at least one unbalance sensor and/or a signal output of
the at least one position sensor and/or a signal output to provide a torque signal.
Preferably, the torque signal is provided by an estimation of the drive torque or
by a desired drive torque of a speed controller of the drive motor. The output signal
of the speed controller characterizes the desired electromagnetic drive torque of
the drive motor and can be used to estimate the drive torque.
[0016] A laundry treatment machine according to claim 6 ensures an easy, reliable and accurate
estimation of the load behaviour. An output layer of the artificial neural network
has at least one signal out. Depending on the training of the artificial neural network
the at least one signal output provides an estimation of at least one of a mass of
the load, an angular position of the load, an axial position of the load, a force
acting on the drum and a torque acting on the drum. The force and the torque are caused
by the drive motor and the load. The at least one signal output provides at least
one output signal which can be used to estimate the dry load at the beginning of the
washing cycle in order to set the amount of resources and energy, the wet load at
the end of the washing cycle and/or the position and magnitude of the unbalanced load.
[0017] A laundry treatment machine according to claim 7 ensures an easy, reliable and accurate
estimate of the load behaviour. The drive motor is directly connected via a drive
shaft with the drum. The drive shaft provides a stiff connection such that the drive
torque is acting directly on the drum. Consequently, the torque signal accurately
corresponds to the drive torque. This results in an accurate and reliable estimation
of the load behaviour, in particular by means of the artificial neural network.
[0018] A laundry treatment machine according to claim 8 ensures an easy, reliable and accurate
estimation of the load behaviour. The compensation unit is used to compensate an unbalanced
load depending on the estimated behaviour. Additionally, the compensation unit can
be used to perform a training of the artificial neural network. The compensation unit
comprises several balancers which can be filled individually with water. By filling
an amount of water in at least one selected balancer in a defined manner the compensation
unit can simulate an unbalanced load. This load is known such that the artificial
neural network can be trained. Preferably, each balancer is divided into at least
two subchambers which can be filled individually with water. By filling a subchamber
at a front side and/or a subchamber at a rear side with an amount of water in a defined
manner the artificial neural network can be trained to estimate an axial position
of an unbalanced load. The compensation unit comprises at least one injection valve,
preferably at least two injection valves, to fill water into the at least one balancer,
in particular into at least one subchamber at a front side and/or rear side. Each
balancer is connected with at least one supply channel, preferably with two supply
channels to supply the water from the at least one injection valve to the at least
one balancer.
[0019] Furthermore, it is an object of the present invention to provide a method to operate
a laundry treatment machine which enables an easy, reliable and accurate estimation
of a load behaviour.
[0020] This object is achieved by a method comprising the steps of claim 9. The advantages
of the method according to the invention correspond to the advantages already described
in connection with the laundry treatment machine according to the invention.
[0021] A method according to claim 10 ensures an easy, reliable and accurate estimation
of the load behaviour. In order to avoid a mechanical impact the laundry treatment
machine is operated below a resonance frequency and an angular speed of resonance
during estimation of the load behaviour and/or training of an artificial neural network.
The angular speed ω is lower than a critical resonance frequency, in particular lower
than 300 rpm. Preferably, 50 rpm ≤ ω ≤ 250 rpm, in particular 75 rpm ≤ ω ≤ 200 rpm,
and in particular 100 rpm ≤ ω ≤ 150 rpm.
[0022] A method according to claim 11 ensures an easy, reliable and accurate estimation
of the load behaviour. Preferably, an artificial neural network is used to estimate
the load behaviour. The artificial neural network is implemented into the control
unit and has to be trained in advance to be able to estimate the load behaviour. In
order to train the artificial neural network at least one known unbalanced load is
positioned in the drum. The artificial neural network is trained by minimizing a quality
function which comprises at least one error between the known behaviour of the provided
load and a behaviour of the provided load which is estimated by means of the artificial
neural network.
[0023] A method according to claim 12 ensures an easy, reliable and accurate estimation
of the load behaviour. The compensation unit is used to train the artificial neural
network. At least one balancer of the compensation unit is filled with an amount of
water in a defined manner such that a known unbalanced load is created. Afterwards
the artificial neural network is trained to estimate the behaviour of the known unbalanced
load. By using the compensation unit the training of the artificial neural network
can be fully automated. This results in a considerable saving of time to train the
artificial neural network.
[0024] A method according to claim 13 ensures an easy, reliable and accurate estimation
of the load behaviour. The accuracy of the estimation can be increased by increasing
the number N of known unbalanced loads which are used to train the artificial neural
network. Preferably, 2 ≤ N ≤ 500, in particular 10 ≤ N ≤ 400, in particular 20 ≤ N
≤ 300, and in particular 50 ≤ N ≤ 200. Preferably, the known unbalanced loads are
different in their mass, in their angular position and/or in their axial position.
[0025] A method according to claim 14 ensures an easy, reliable and accurate estimation
of the load behaviour. The artificial neural network comprises weight parameters which
have to be adapted during the training process. The weight parameters are adapted
by minimising a quality function. The quality function comprises at least one error
between a known behaviour of the provided load and an estimated behaviour of the provided
load. For example, to estimate the mass of the load the corresponding quality function
comprises an error between the known mass and an estimated mass.
[0026] A method according to claim 15 ensures an easy, reliable and accurate estimation
of the load behaviour. The trained artificial neural network is used to estimate the
behaviour of a load caused by the laundry inside of the drum during normal operation
of the laundry treatment machine. The estimated behaviour of the load can be used
to compensate the unbalance caused by the load by means of the compensation unit.
In order to compensate the unbalanced load at least one balancer is filled with water
such that the unbalance of the load is decreased. By compensating the unbalance of
the load the mechanical stress on the drum and the bearings is reduced and a mechanical
damage is prevented.
[0027] Further features, advantages and details of the invention will be apparent from the
following description of an embodiment which refers to the accompanying drawings.
- Fig. 1
- shows a schematic view of a laundry treatment machine,
- Fig.2
- shows a rear side of a washing unit of the laundry treatment machine in Fig. 1,
- Fig. 3
- shows a perspective view of a compensation unit of the laundry treatment machine in
Fig. 1,
- Fig. 4
- shows the design of an artificial neural network which is implemented into a control
unit of the laundry treatment machine in Fig. 1,
- Fig. 5
- shows a flow chart of a method to operate the laundry treatment machine in Fig. 1,
and
- Fig. 6
- shows a schematic block diagram of the artificial neural network during a training
process.
[0028] Fig. 1 shows a laundry treatment machine, namely a washing machine 1 with a cabinet
2 and a washing unit 3. The washing unit 3 comprises a tub 4 and a drum 5. The tub
4 is mounted to the cabinet 2 via dampers 6 and springs 7. The drum 5 is mounted in
a rotatable manner to the tub 4. The tub 4 comprises a front wall F, a rear wall R
and a circumferential wall W which is connected to the front wall F and the rear wall
R. The drum 5 is connected via a drive shaft 8 with a drive motor 9. The drive motor
9 is mounted at the rear wall R of the tub 4. The drive motor 9 rotates the drum 5
around a horizontal rotational axis 10 by exerting a drive torque T
em.
[0029] The cabinet 2 comprises a base 11, four side walls 12 and a top cover 13. The base
11 defines a base plane E
B which runs in parallel to a horizontal x-direction and a horizontal y-direction.
The rotational axis 10 and the base plane E
B define a vertical plane E
V1. The vertical plane E
V1 runs perpendicular to the base plane E
B. The vertical plane E
V1 runs in parallel to the horizontal x-direction and a vertical z-direction. The x-direction,
the y-direction and the z-direction run in pairs perpendicular to each other and form
a Cartesian coordinate system.
[0030] The washing machine 1 comprises a first unbalance sensor 14, a second unbalance sensor
15 and a position sensor 16. The first unbalance sensor 14 is mounted to the circumferential
wall W adjacent to the front wall F, whereas the second unbalance sensor 15 is mounted
to the circumferential wall W adjacent to the rear wall R. The first unbalance sensor
14 determines a movement of the washing unit 3 transverse to the rotational axis 10
at the front wall F and provides a first unbalance signal a
1, whereas the second unbalance sensor 15 determines a movement of the washing unit
3 transverse to the rotational axis 10 at the rear wall R and provides a second unbalance
signal a
2.
[0031] Fig. 2 shows the washing unit 3 without the rear wall R of the tub 4. The vertical
plane E
V1 and each of the unbalance sensors 14, 15 enclose an angle a, wherein 0° < α < 90°,
in particular 15° ≤ α ≤ 75°, and in particular 30° ≤ α ≤ 75°. For each unbalance sensor
14, 15 the angle α is defined in a projection plane, wherein the rotational axis 10
runs perpendicular to each projection plane. The unbalance sensors 14, 15 are arranged
in the z-direction above a horizontal plane E
H. The horizontal plane E
H includes the rotational axis 10 and runs in parallel to the base plane E
B. The first unbalance sensor 14 and the second unbalance sensor 15 have a distance
from each other in the x-direction and are mounted at the tub 4 at different sides
of a vertical plane E
V2. The vertical plane E
V2 and the rotational axis 10 run perpendicular to each other, whereas the vertical
plane E
V2 includes a centre of gravity G of the washing unit 3. The first unbalance sensor
14 and the second unbalance sensor 15 are uniaxial accelerometer sensors.
[0032] The position sensor 16 is a once per revolution sensor. The position sensor 16 comprises
a detector 17 and a part 18 to be detected. The detector 17 is attached to the rear
wall R of the tub 4. The drum 5 comprises a front wall f, a rear wall r and a circumferential
wall w which is connected to the front wall f and the rear wall r. The drum 5 further
comprises a starlike stiffening member S which is attached to the rear wall r. The
part 18 to be detected is attached at the stiffening member S. The position sensor
16 provides an absolute angular position signal ϕ of the drum 5.
[0033] The washing machine 1 comprises a compensation unit 19. The compensation unit 19
comprises three balancers A
1, A
2, A
3 which move the laundry and can be filled with water. The balancers A
1, A
2, A
3 are mounted in equal angular distances Δϕ to an inner side of the drum 5. Each balancer
A
1, A
2, A
3 is divided by partition walls p into subchambers s. Adjacent subchambers s are connected
to each other via a through hole t. The subchambers s can be successively filled with
water from the front wall f and/or the rear wall r. Each balancer A
1, A
2, A
3 is filled with water via supply channels Z
11, Z
12, Z
21, Z
22, Z
31, Z
32, wherein the supply channels Z
11, Z
21, Z
31 serve to fill the balancers A
1, A
2, A
3 from the rear wall r and the supply channels Z
12, Z
22, Z
32 serve to fill the balancers A
1, A
2, A
3 from the front wall f. The water is injected into the supply channels Z
11, Z
21, Z
31 via a first nozzle N
1 and into the supply channels Z
12, Z
22, Z
32 via a second nozzle N
2. The injected water is forced into the balancers A
1, A
2, A
3 by a centrifugal force which is caused by a rotation of the drum 5.
[0034] Furthermore, the washing machine 1 comprises a control unit 20 to control the operation.
The control unit 20 comprises a speed controller 21 and a torque controller 22. The
torque controller 22 is part of an inner control loop or a torque control loop to
control the drive torque T
em of the drive motor 9. For example, the torque controller 22 is a PI controller. The
speed controller 21 is part of an outer control loop or a speed control loop to control
the angular speed ω of the drive motor 9. For example, the speed controller 21 is
a PI controller. The speed controller 21 is provided with a difference of a desired
angular speed and measured or estimated angular speed ω of the drive motor 9. The
output signal of the speed controller 21 is a desired drive torque T*
em which is used as an input signal for the torque controller 22.
[0035] The control unit 20 comprises an artificial neural network NN which serves to estimate
the behaviour of a load L. The load L is caused by the laundry inside of the drum
5. The artificial neural network NN has an input layer L
I, two hidden layers L
H1, L
H2 and an output layer L
O. The input layer L
I has four neurons which provide four signal inputs to receive four input signals s
1, s
2, s
3, s
4. Furthermore, the output layer L
O has five neurons with five signal outputs. The five signal outputs provide five output
signals o
1, o
2, o
3, o
4, o
5. The hidden layers L
H1, L
H2 each comprise five neurons. Each neuron of the input layer L
I is connected with each neuron of the first hidden layer L
H1. Each neuron of the first hidden layer L
H1 is connected to each neuron of the second hidden layer L
H2. Furthermore, each neuron of the second hidden layer L
H2 is connected to each neuron of the output layer L
O. The artificial neural network NN is designed as a feedforward network.
[0036] In general, each neuron can be described by the equation
wherein
- xi
- denotes the input signals of the neuron,
- wi
- denotes weight parameters assigned to each input signal,
- w0
- denotes a bias weight parameter,
- n
- denotes the number of input signals,
- i
- denotes an index,
- f
- denotes a transfer function and
- o
- denotes an output signal of the neuron.
[0037] The first unbalance sensor 14 provides the first unbalance signal a
1 which characterizes a movement of the washing unit 3 transverse to the rotational
axis 10 near the front wall F. Correspondingly, the second unbalance sensor 15 provides
the second unbalance signal a
2 which characterizes a movement of the washing unit 3 transverse to the rotational
axis 10 near the rear wall R. The first unbalance signal a
1 is transferred into a frequency domain by calculating a fourier transformation. The
first input signal s
1 of the artificial neural network NN is equal to the transferred first unbalance signal
a
1. Correspondingly, the second unbalance signal a
2 is transferred into a frequency domain by calculating a fourier transformation. The
second input signal s
2 of the artificial neural network NN is equal to the transferred second unbalance
signal a
2.
[0038] The position sensor 16 provides the position signal ϕ. The position sensor 16 is
connected to a third signal input such that the third input signal s
3 is equal to the position signal ϕ.
[0039] The speed controller 21 is connected to a fourth signal input such that the fourth
input signal s
4 is equal to the desired drive torque T*
em.
[0040] The artificial neural network NN is trained such that a first output signal o
1 estimates the mass m of the load L, a second output signal o
2 estimates an axial position X
L of the load L, a third output signal o
3 estimates an angular position ϕ
L of the load L, a fourth output signal o
4 estimates a torque T acting on the drum 5 and a fifth output signal o
5 estimates a force F acting on the drum 5. The torque T depends on the drive torque
T
em and a toque T
L caused by the load L such that T = T
em + T
L. The force F can be described by F = T/r, wherein r is the radius of the drum 5.
For the torque T
L caused by the load L applies: T
L = m·g·r·sin((ϕ
L), wherein g denotes the gravitational acceration.
[0041] In the following the operation of the washing machine 1 is described in detail.
[0042] First of all, the artificial neural network NN has to be trained. In a first step
S
1 a known unbalanced load L is generated by means of the compensation unit 19. At least
one of the balancers A
1, A
2, A
3 is filled with a defined amount of water such that an unbalanced load L is simulated.
The load L has a known mass m, a known axial position X
L, a known angular position ϕ
L such that the drive motor 9 and the load L create a known torque T and a known force
F.
[0043] In a second step S
2 the washing machine 1 is operated and the neural network NN is trained. The training
process is shown in fig. 6, wherein
s is a vector of all input signals s
1 to s
4 and
o is a vector of all output signals o
1 to o
5. The known load L provides desired output signals of the artificial neural network
NN which are summarized in a vector
oL. In order to train the artificial neural network NN error signals e
1 to e
5 are calculated which are summarized in a vector
e, wherein
e =
o -
oL. By means of a quality function which comprises the error signals e
1 to e
5 the weight parameters w
0, w
i of the artificial neural network NN are adapted such that the quality function is
minimized.
[0044] The steps S
1 and S
2 are repeated for a number N of known unbalanced loads L, wherein 2 ≤ N ≤ 500. The
known unbalanced loads L are different of each other with respect to their mass m,
their axial positions x
L and their angular positions ϕ
L. By using the compensation unit 19 to train the artificial neural network NN, the
training process can be automized.
[0045] In order to avoid the excitation of a resonance frequency, the training process takes
place at an angular speed ω of the drum 5 which is lower than an angular speed of
resonance, wherein in particular 50 rpm ≤ ω ≤ 250 rpm, in particular 75 rpm ≤ ω ≤
200 rpm, and in particular 100 rpm ≤ ω ≤ 150 rpm.
[0046] After completion of the training process the artificial neural network NN can be
used in a step S
3 to estimate the behaviour of an unknown load L during normal operation of the washing
machine 1. In step S
3 the adaption of the weight parameters w
0, w
i is finished and disabled such that the weight parameters w
0, w
i are constant. Due to the trained artificial neural network NN the behaviour of the
unknown load L, namely the output signals o
1 to o
5 according to fig. 4 can be estimated.
[0047] In a step S
4 the output signals o
1 to o
5 can be used to compensate the unbalance of the load L by means of the compensation
unit 19. Depending on the estimated behaviour of the load L at least one of the balancers
A
1, A
2, A
3 is filled with a suitable amount of water such that the unbalance of the load L is
reduced. A compensation controller 23 determines the at least one balancer A
1, A
2, A
3, the amount of water and the nozzle N
1, N
2 to compensate the unbalanced load L.
[0048] Due to the angular position of the first unbalance sensor 14 and the second unbalance
sensor 15 the unbalance signals a
1, a
2 have a good signal quality. Furthermore, due to their angular position the unbalance
sensors 14, 15 do not reduce the available space between the tub 4 and the cabinet
2. The potion sensor 16 provides an absolute angular position ϕ of the drum 5 since
exactly one part 18 to be detected is attached directly at the drum 5. Furthermore,
the angular position ϕ has a high quality since the measurement is not affected by
mechanical disturbances.
1. Laundry treatment machine with
- a drum (5), wherein
-- the drum (5) is rotatable around a rotational axis (10),
-- the rotational axis (10) defines a vertical plane (EV1),
- a drive motor (9) to rotate the drum (5) around the rotational axis (10) by exerting
a drive torque (Tem),
- at least one unbalance sensor (14, 15) to determine a movement of the drum (5) transverse
to the rotational axis (10),
- at least one position sensor (16) to determine an angular position (ϕ) of the drum
(5), and
- a control unit (20) to estimate a behaviour of a load (L),
characterized in
that the at least one unbalance sensor (14, 15) and the vertical plane (EV1) enclose an angle α, wherein 0° < α < 90°,
and/or
that the at least one position sensor (16) comprises a detector (17) and at least one
part (18) to be detected, wherein the at least one part (18) to be detected is arranged
at the drum (5).
2. Laundry treatment machine according to claim 1, characterized in that the at least one unbalance sensor (14, 15) is arranged above a horizontal plane (EH) which includes the rotational axis (10).
3. Laundry treatment machine according to claim 1 or 2, characterized by a first unbalance sensor (14) and a second unbalance sensor (15), which in particular
have a distance from each other in a direction (x) parallel to the axis of rotation
(10).
4. Laundry treatment machine according to at least one of the preceding claims, characterized in
that the control unit (20) comprises an artificial neural network (NN) to estimate the
behaviour of the load (L).
5. Laundry treatment machine according to claim 4, characterized in that the artificial neural network (NN) has at least one signal input, wherein at least
one unbalance signal (a1, a2) of the at least one unbalance sensor (14, 15) and/or at least one angular position
signal (ϕ) of the at least one position sensor (16) and/or a torque signal (T*em) characterizing the drive torque (Tem) is supplied to the at least one signal input.
6. Laundry treatment machine according to claim 4 or 5, characterized in
that the artificial neural network (NN) has at least one signal output to provide an estimation
of at least one of a mass (m) of the load (L), an angular position ((ϕL) of the load
(L), an axial position (xL) of the load (L), a force (F) acting on the drum (5) and a torque (T) acting on the
drum (5).
7. Laundry treatment machine according to at least one of the preceding claims, characterized in
that the drive motor (9) is directly connected to the drum (5).
8. Laundry treatment machine according to at least one of the preceding claims, characterized
by a compensation unit (19) to compensate an unbalance of the load (L) depending on
the estimated behaviour.
9. Method to operate a laundry treatment machine with the steps of:
- providing a laundry treatment machine (1) according to at least one of claims 1
to 8, and
- estimating the behaviour of the load (L) during operation of the laundry treatment
machine (1).
10. Method according to claim 9, characterized in that the laundry treatment machine (1) is operated at an angular speed ω of the drum (5)
which is lower than an angular speed of resonance, wherein in particular 50 rpm ≤
ω ≤ 250 rpm.
11. Method according to claim 9 or 10, characterized by the step of training an artificial neural network (NN).
12. Method according to claim 11, characterized in that a compensation unit (19) provides at least one known unbalanced load (L) to train
the artificial neural network (NN).
13. Method according to claim 11 or 12, characterized in that the artificial neural network (NN) is trained automatically by providing a number
N of unbalanced loads (L) which are different of each other and known, wherein in
particular 2 ≤ N ≤ 500.
14. Method according to at least one of claims 11 to 13, characterized in that weight parameters (w0, wi) of the artificial neural network (NN) are adapted by minimizing a quality function,
wherein the quality function comprises at least one error (e1 to e5) between a known behaviour of the provided load (L) and an estimated behaviour of
the provided load (L).
15. Method according to at least one of claims 11 to 14, characterized in that estimating the behaviour of the load (L) during operation of the laundry treatment
machine (1) takes place by means of the trained artificial neural network (NN).