Method for calibrating sensors
View Patent ↗A method for calibrating a sensor, particularly a turbidity sensor in a domestic appliance, such as a dishwasher or washing machine, with the aid of reference values, including the determination of measuring values, with at least one measured value selected using probability calculus that is no longer taken into account when determining the reference values.
1. A method for calibrating a turbidity sensor in a domestic appliance, with the aid of reference values comprising the following steps:
determining a plurality of measured values in at least one cleaning program sequence executed by a computer, the cleaning program sequence having a plurality of sequential time positions at which measured values can be determined, the plurality of measured values including at least two measured values being from the same time position within the program sequence;
calculating, using a program executed by the computer, at least one measured value by at least one of statistical methods and probability calculus for omission from the following step;
determining at least one possible reference value for calibrating the sensor from the non-selected measured values; and
selecting an optimal reference value from the least one possible reference value if more than two possible reference values have been determined.
2. The method according to claim 1 , wherein the selection of the at least one measured value by at least one of statistical methods and probability calculus which is no longer taken into account in the following step is made in each case from a series of measured values which are measured at the same times within a at least one washing program sequence executed by the computer.
3. The method according to claim 1 , wherein the following steps are carried out for selecting at least one measured value (m a s ):
determining the arithmetic mean (d 1 to d a ) for the measured values (m a s for a=1, 2, . . . a) according to the formula
d
a
=
m
a
1
+
m
a
2
+
m
a
3
+
m
a
4
+
…
+
m
a
s
s
,
determining the mean square error (σ a 2 for σ 1 2 to σ a 2 ) with d a from the first step using the formula
σ
a
2
=
(
m
1
1
-
d
a
)
2
+
(
m
1
2
-
d
a
)
2
+
…
+
(
m
1
s
-
d
a
)
2
s
,
determining the probable limits of the possible reference value (m* a s , m a s for m* 1 s , m a s to m* a s , m a s ) wherein these lie within
d
a
±
0
,
6746
s
and
selecting the measured values (m a s ) which lie outside these limits.
4. The method according to claim 3 , wherein if no measured value (m a s ) lies outside the probable limits of the possible reference value (m* a s , m a s ) the interval of the probable limits of the possible reference value (m* a s , m a s ) is set as smaller so that at least one measured value (m a s ) lies outside and this at least one measured value (m a s ) is selected.
5. The method according to claim 4 , wherein empirical values are additionally used to determine the probable limits of the possible reference value (m* a s , m a s ), the empirical values being automatically adapted to changing relationships in the process sequence.
6. The method according to claim 1 , wherein the at least one possible reference value ( m a s ) for the calibration of the sensor is determined from the remaining non-selected measured values (m a s ) by averaging performed by the computer.
7. The method according to claim 1 , wherein the at least one possible reference value (m* a s ) for the calibration of the sensor is determined from the remaining non-selected measured values (m a s ) by selecting a measured value (m a s ) by means of at least one of statistical methods and probability calculus performed by the computer.
8. The method according to claim 7 , wherein the measured value (m a s ) with the highest probability density within the non-selected measured values (m a s ) is selected.
9. The method according to claim 7 , wherein that measured value (m a s ) is selected as a possible reference value (m* a s ) that lies closest to the arithmetic mean of the non-selected measured value m a s by the following steps:
determine the arithmetic mean (d′ a for a=1, 2, a) of the non-selected measured values (m a s )
determining the magnitude of |d′ a −m a s |, wherein that measured value (m a s ) is selected for which the magnitude of |d′ a −m a s | is smallest.
10. The method according to claim 1 , wherein from the possible reference values ( m a s , m* a s ) the most optimum is selected as the reference value ( m a s , m* a s ) for the calibration of the sensor, which can include a reference value ( m a s , m* a s ) having the lowest degree of contamination.
11. A domestic appliance in which a method according to claim 1 , can be implemented.
12. A computer program embodied on a computer-readable medium with program code means executed by said computer to carry out all the steps of a method according to claim 1 , if the computer program is carried out on said computer-readable medium or a corresponding processing unit.
13. A computer program product stored on a computer-readable data carrier with program code means executed by said computer-readable data carrier to carry out all the steps of a method according to claim 1 , if the computer program is carried out said computer-readable data carrier or a corresponding processing unit.
14. A method for calibrating a turbidity sensor in a domestic appliance, with the aid of reference values comprising the following steps:
determining at least two measured values in at least one cleaning program sequence executed by a computer, the cleaning program sequence having a plurality of sequential time positions at which measured values can be determined, the plurality of measured values including at least two measured values being from the same time position within the program sequence;
determining at least one possible reference value from the measured values by selecting a measured value using methods of at least one of probability calculus and statistics executed by the computer; and
selecting an optimal reference value from the possible reference values if more than one possible reference value has been determined.
15. The method according to claim 14 , wherein the selection of the at least one measured value (m a s ) is made by at least one of statistical methods and probability calculus executed by a computer in each case from a series of measured values which were measured at the same times (t a ) within at least one washing program sequence executed by the computer.
16. The method according to claim 15 , wherein from the reference values (m* a s ) the most optimum is selected as the reference value (m* a s ) for the calibration of the sensor, which can include a reference value (m* a s ) having the lowest degree of contamination.
17. The method according to claim 14 , wherein that measured value (m a s ) is selected as a reference value (m* a s ) that lies closest to the arithmetic mean of the non-selected measured values m a s by the following steps:
determine the arithmetic mean (d′ a for a=1, 2, a) of the non-selected measured values (m a s ); and
determining the magnitude of |d′ a −m a s |, wherein that measured value m a s is selected for which the magnitude of |d′ a −m a s | is smallest.