Adaptive filter model for motor vehicle sensor signals
First Claim
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1. A method of calculating a physical parameter value (X) of a wheeled vehicle indirectly using at least two directly measurable input signals, comprising the steps of:
- (a) receiving a first input sensor signal (y1(t)) that is dependent on a first physical input parameter affecting a condition of the wheeled vehicle;
(b) receiving a second input sensor signal (y2(t)) that is dependent on a second physical input parameter affecting a condition of the wheeled vehicle, wherein the second physical input parameter can be any one of the same as physical parameter value (X), the same as the first physical input parameter, and different from the first physical input parameter;
(c) recursively filtering the first and second physical input parameters by means of an adaptive filter based on a predetermined model of the condition of the wheeled vehicle, wherein the input signals to said model include the first physical input parameter (y1(t)), the second physical input parameter (y2(t)), a first offset scaling factor (c1(t)) for the first sensor signal, and a second offset scaling factor (c2(t)) for the second sensor signal, and wherein the model output signals include a first offset error signal (b1(t)) and a second offset error signal (b2(t)), and the physical parameter value (X);
(d) estimating the values of said first offset error (b1(t)) and the second offset error (b2(t)) by means of said adaptive filter, wherein at least one offset error relates to the wheel radius; and
(e) calculating the physical parameter value (X) using the adaptive filter from the input sensor signals y1(t) and y2(t) such that offset errors in the calculation are compensated for by means of the first and second offset error parameters (b1(t)) and (b2(t)) and the offset scaling factors c1(t) and c2(t).
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Abstract
A sensor system for combining first and second sensor signals, and generating a physical parameter values dependent on said sensor signals used in autocalibrating sensors improving the performance and quality of existing sensor signals and virtual sensors realizing new sensors by combining and integrating in adaptive filter models sensor signals representing same or different types of physical parameters.
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Citations
48 Claims
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1. A method of calculating a physical parameter value (X) of a wheeled vehicle indirectly using at least two directly measurable input signals, comprising the steps of:
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(a) receiving a first input sensor signal (y1(t)) that is dependent on a first physical input parameter affecting a condition of the wheeled vehicle; (b) receiving a second input sensor signal (y2(t)) that is dependent on a second physical input parameter affecting a condition of the wheeled vehicle, wherein the second physical input parameter can be any one of the same as physical parameter value (X), the same as the first physical input parameter, and different from the first physical input parameter; (c) recursively filtering the first and second physical input parameters by means of an adaptive filter based on a predetermined model of the condition of the wheeled vehicle, wherein the input signals to said model include the first physical input parameter (y1(t)), the second physical input parameter (y2(t)), a first offset scaling factor (c1(t)) for the first sensor signal, and a second offset scaling factor (c2(t)) for the second sensor signal, and wherein the model output signals include a first offset error signal (b1(t)) and a second offset error signal (b2(t)), and the physical parameter value (X); (d) estimating the values of said first offset error (b1(t)) and the second offset error (b2(t)) by means of said adaptive filter, wherein at least one offset error relates to the wheel radius; and (e) calculating the physical parameter value (X) using the adaptive filter from the input sensor signals y1(t) and y2(t) such that offset errors in the calculation are compensated for by means of the first and second offset error parameters (b1(t)) and (b2(t)) and the offset scaling factors c1(t) and c2(t). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. An apparatus for calculating a physical parameter value (X) of a wheeled vehicle indirectly using at least two directly measurable input signals, comprising:
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(a) a first input sensor signal (y1(t)) that is dependent on a first physical input parameter affecting a condition of the wheeled vehicle; (b) a second input sensor signal (y2(t)) that is dependent on a second physical input parameter affecting a condition of the wheeled vehicle, wherein the second physical input parameter can be any one of the same as physical parameter value (X), the same as the first physical input parameter, and different from the first physical input parameter; (c) means for recursively filtering the first and second physical input parameters by means of an adaptive filter based on a predetermined model of the condition of the wheeled vehicle, wherein the input signals to said model include the first physical input parameter (y1(t)), the second physical input parameter (y2(t)), a first offset scaling factor (c1(t)) for the first sensor signal, and a second offset scaling factor (c2(t)) for the second sensor signal, and wherein the model output signals include a first offset error signal (b1(t)) and a second offset error signal (b2(t)), and the physical parameter value (X); (d) means for estimating the values of said first offset error (b1(t)) and the second offset error (b2(t)) by means of said adaptive filter, wherein at least one offset error relates to the wheel radius; and (e) means for calculating the physical parameter value (X) using the adaptive filter from the input sensor signals y1(t) and y2(t) such that offset errors in the calculation are compensated for by means of the first and second offset error parameters (b1(t)) and (b2(t)) and the offset scaling factors c1(t) and c2(t). - View Dependent Claims (46)
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47. A computer program directly loadable into the internal memory of a digital computer, comprising program code for calculating a physical parameter value (X) of a wheeled vehicle indirectly using measurable input signals, the program code comprises sets of instructions for:
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(a) receiving a first input sensor signal (y1(t)) that is dependent on a first physical input parameter affecting a condition of the wheeled vehicle; (b) receiving a second input sensor signal (y2(t)) that is dependent on a second physical input parameter affecting a condition of the wheeled vehicle, wherein the second physical input parameter can be any one of the same as physical parameter value (X), the same as the first physical input parameter, and different from the first physical input parameter; (c) recursively filtering the first and second physical input parameters by means of an adaptive filter based on a predetermined model of the condition of the wheeled vehicle, wherein the input signals to said model include the first physical input parameter (yl(t)), the second physical input parameter (y2(t)), a first offset scaling factor (c1(t)) for the first sensor signal, and a second offset scaling factor (c2(t)) for the second sensor signal, and wherein the model output signals include a first offset error signal (b1(t)) and a second offset error signal (b2(t)), and the physical parameter value (X); (d) estimating the values of said first offset error (b1(t)) and the second offset error (b2(t)) by means of said adaptive filter, wherein at least one offset error relates to the wheel radius; and
(e) calculating the physical parameter value (X) using the adaptive filter from the input sensor signals y1(t) and y2(t) such that offset errors in the calculation are compensated for by means of the first and second offset error parameters (b1(t)) and (b2(t)) and the offset scaling factors c1(t) and c2(t).
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48. A method of calculating a physical parameter value (X) of a wheeled vehicle indirectly by recursively filtering at least two measurable input sensor signals, comprising the steps of:
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processing a plurality of input sensor signals (y1(t),y2(t)) that are dependent on first and second physical input parameters respectively that affect a condition of the wheeled vehicle; recursively filtering the first and second physical input parameters by means of an adaptive filter based on a predetermined model of the condition of the wheeled vehicle, wherein the input signals to said model include the first physical input parameter (y1(t)), the second physical input parameter (y2(t)), a first offset scaling factor (c1(t)) for the first sensor signal, and a second offset scaling factor (c2(t)) for the second sensor signal, and wherein the model output signals include a first offset error signal (b1(t)) and a second offset error signal (b2(t)), and the physical parameter value (X); estimating the values of said first offset error (b1(t)) and said second offset error (b2(t)) by means of recursively filtering with an adaptive filter, wherein at least one offset error relates to the wheel radius; calculating one or more physical parameter value (X) signals using the adaptive filter; and using the first and second offset errors (b1(t),b2(t)) to adjust the physical parameter values (X) to a value that is more representative of its actual value.
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Specification