Method of calibrating a sensor
First Claim
1. A method of calibrating a sensor, in which at most as many influence variables affecting the measuring results are considered as measurable quantities are detected by the sensor, the number of influence variables being composed of at least one disturbance variable influencing the measurement and at least one target quantity to be determined from the measurable quantities, and comprising the steps of:
- defining several values of the at least one target quantity and defining several values of the at least one disturbance variable for each of the defined values of the at least one target quantity;
detecting the corresponding values of the measurable quantities for all combinations of defined values of the at least one target quantity with corresponding defined Values of the at least one disturbance variable;
determining from each of the defined values of the at least one target quantity and the corresponding detected values of the measurable quantities a respective set of coefficients;
associating each of the sets of coefficients to the corresponding defined values of the at least one target quantity; and
storing the sets of coefficients,wherein for determining an unknown value of the at least one target quantity the corresponding values of the measurable quantities are detected, wherein the detected values of the measurable quantities for the corresponding unknown value of the at least one target quantity are multiplied with each of the stored sets of coefficients and added up to a subtotal for each set of coefficients, the subtotal being associated to the same defined value of the at least one target quantity as the respective set of coefficients, and that a range of values between two successive defined values of the at least one target quantity is determined as a range of values for the unknown target quantity, the deviation from the corresponding subtotal being positive for one of these two defined values of the at least one target quantity, whereas the deviation from the corresponding subtotal is negative for the other of these two defined values of the at least one target quantity.
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Abstract
To suppress and compensate influences of disturbance variables, a method of calibrating a sensor is disclosed, in which at most as many so-called influence variables influencing the measuring result are considered as measurable quantities are detected by the sensor, the set of the influence variables being composed of at least one disturbance variable influencing the measurement and at least one target quantity to be determined from the measurable quantities. The method in accordance with the invention is characterized in that several values of the target quantity and several states characterized by the disturbance variable are defined, that for all combinations of defined values of the target quantity with defined states the corresponding values of the measurable quantities are acquired, that from one each of the defined values of the target quantity and the corresponding values of the measurable quantity respectively a set of coefficients is determined for all defined states, and that the sets of coefficients are associated each to the corresponding value of the target quantity and stored.
37 Citations
18 Claims
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1. A method of calibrating a sensor, in which at most as many influence variables affecting the measuring results are considered as measurable quantities are detected by the sensor, the number of influence variables being composed of at least one disturbance variable influencing the measurement and at least one target quantity to be determined from the measurable quantities, and comprising the steps of:
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defining several values of the at least one target quantity and defining several values of the at least one disturbance variable for each of the defined values of the at least one target quantity; detecting the corresponding values of the measurable quantities for all combinations of defined values of the at least one target quantity with corresponding defined Values of the at least one disturbance variable; determining from each of the defined values of the at least one target quantity and the corresponding detected values of the measurable quantities a respective set of coefficients; associating each of the sets of coefficients to the corresponding defined values of the at least one target quantity; and storing the sets of coefficients, wherein for determining an unknown value of the at least one target quantity the corresponding values of the measurable quantities are detected, wherein the detected values of the measurable quantities for the corresponding unknown value of the at least one target quantity are multiplied with each of the stored sets of coefficients and added up to a subtotal for each set of coefficients, the subtotal being associated to the same defined value of the at least one target quantity as the respective set of coefficients, and that a range of values between two successive defined values of the at least one target quantity is determined as a range of values for the unknown target quantity, the deviation from the corresponding subtotal being positive for one of these two defined values of the at least one target quantity, whereas the deviation from the corresponding subtotal is negative for the other of these two defined values of the at least one target quantity. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of calibrating a sensor, in which at most as many influence variables affecting the measuring results are considered as measurable quantities are detected by the sensor, the number of influence variables being composed of at least one disturbance variable influencing the measurement and at least one target quantity to be determined from the measurable quantities, and comprising the steps of:
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defining several values of the at least one target quantity and defining several values of the at least one disturbance variable for each of the defined values of the at least one target quantity; detecting the corresponding values of the measurable quantities for all combinations of defined values of the at least one target quantity with corresponding defined values of the at least one disturbance variable; determining from each of the defined values of the at least one target quantity and the corresponding detected values of the measurable quantities a respective set of coefficients; associating each of the sets of coefficients to the corresponding defined values of the at least one target quantity; and storing the sets of coefficients; wherein said sensor is an eddy current sensor having at least one measuring coil, with the distance d between the eddy current sensor and a target forming the at least one target quantity, the electric conductivity and the effective permeability of the target forming the at least one disturbance variable, and the real and imaginary parts of the impedance of the measuring coil at different frequencies being acquired as measurable quantities Ml (l=1, . . . , m) and wherein several distance values di (i=1, . . . , n) and several values ZKj (j=1, . . . , k) of the electric conductivity and the effective permeability of the target are defined, wherein for all combinations of distance values di with combinations of values ZKj the corresponding measurable quantities Ml are detected, wherein from each one of the distance values di and the corresponding values of measurable quantities Ml for all combinations of values ZKj a set of coefficients ki (ki =(ki1, . . . , kim) is determined, and that the sets of coefficients ki are associated each to the corresponding distance value di and stored. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A method of calibrating a sensor, in which at most as many influence variables affecting the measuring results are considered as measurable quantities are detected by the sensor, the number of influence variables being composed of at least one disturbance variable influencing the measurement and at least one target quantity to be determined from the measurable quantities, and comprising the steps of:
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defining several values of the at least one target quantity and defining several values of the at least one disturbance variable for each of the defined values of the at least one target quantity; detecting the corresponding values of the measurable quantities for all combinations of defined values of the at least one target quantity with corresponding defined values of the at least one disturbance variable; determining from each of the defined values of the at least one target quantity and the corresponding detected values of the measurable quantities a respective set of coefficients; associating each of the sets of coefficients to the corresponding defined values of the at least one target quantity; and storing the sets of coefficients; wherein said sensor is an eddy-current sensor having at least one measuring coil, wherein the distance d between the eddy current sensor and a target is considered as the at least one disturbance variable, the electric conductivity and the effective permeability of the target form the at least one target quantity, and the real and imaginary parts of the impedance of the measuring coil are detected at different frequencies as measurable quantities Ml (l=1, . . . , m). - View Dependent Claims (17, 18)
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Specification