System and method for performing auto-location of a tire pressure monitoring sensor arranged with a vehicle wheel using confidence interval analysis and rollback events
First Claim
1. A wheel auto-location method, comprising:
- receiving at a control unit of a vehicle, from one of a plurality of tire pressure monitoring (TPM) sensors, a radio frequency (RF) transmission that indicates a TPM sensor wheel phase angle measurement point during a rotation of a wheel and TPM sensor parameters, wherein the RF transmission is associated with a phase correlation data storage event trigger;
storing a current content of a rolling window of antilock brake system (ABS) data for each of a plurality of ABS sensors indicative of a wheel phase angle in response to the phase correlation data storage event trigger, wherein a time period covered by the rolling window is the same or greater than a time period between the TPM sensor wheel phase angle measurement point and a receipt point of the RF transmission, and the current content of the rolling window corresponds to the ABS data incremented between the TPM sensor wheel phase angle measurement point and the receipt point of the RF transmission;
calculating a time of the TPM sensor wheel phase angle measurement point based on the time period between the TPM sensor wheel phase angle measurement point and the receipt point of the RF transmission;
determining a relevant ABS data value at the time of the TPM sensor wheel phase angle measurement point from the current content of the rolling window of the ABS data based on the TPM sensor wheel phase angle measurement point over time;
receiving further measurements that indicate the TPM sensor wheel phase angle at multiple points in time;
determining the relevant ABS data for each of the plurality of ABS sensors for each of the multiple points in time for which the TPM sensor wheel phase angle is received;
generating a histogram array for the relevant ABS data for each of the plurality of ABS sensors, the histogram array comprising a plot of the relevant ABS data and the TPM sensor wheel phase angle;
applying a confidence interval to each histogram array of the relevant ABS data, wherein the confidence interval excludes outlier data;
calculating a confidence interval (COIN) width value from each histogram array from which the outlier data has been excluded; and
applying an auto-location algorithm to identify a specific location of the wheel based on determining which of the plurality of ABS sensors generates the histogram with the lowest COIN width value for the TPM sensor wheel phase angle and assigning one of the plurality of TPM sensors to a same wheel location as the ABS sensor having the lowest COIN width value.
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Accused Products
Abstract
Auto-location systems and methods of tire pressure monitoring sensor units arranged with a wheel of a vehicle detect a predetermined time (T1) when a wheel phase angle reaches angle of interest using a rim mounted or a tire mounted sensor. The systems and methods transmit a radio frequency message associated with a wheel phase angle indication. The wheel phase angle indication triggers wheel phase and/or speed data such as ABS data at the predetermined time (T1) to be stored. A correlation algorithm is executed to identify the specific location of a wheel based on the wheel phase and/or speed data at the predetermined time (T1). TPM sensor parameters from a tire pressure monitoring sensor unit are assigned to the specific location of the wheel based on a confidence interval width analysis of the ABS data at the predetermined (T1). The confidence interval width analysis identifies the specific location of the wheel whose ABS sensor shows a lowest confidence interval width as a result of a normal distribution pattern or similar pattern. The confidence interval width analysis may calculate a weighted cumulative confidence interval width for the ABS data which experience rollback events.
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Citations
20 Claims
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1. A wheel auto-location method, comprising:
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receiving at a control unit of a vehicle, from one of a plurality of tire pressure monitoring (TPM) sensors, a radio frequency (RF) transmission that indicates a TPM sensor wheel phase angle measurement point during a rotation of a wheel and TPM sensor parameters, wherein the RF transmission is associated with a phase correlation data storage event trigger; storing a current content of a rolling window of antilock brake system (ABS) data for each of a plurality of ABS sensors indicative of a wheel phase angle in response to the phase correlation data storage event trigger, wherein a time period covered by the rolling window is the same or greater than a time period between the TPM sensor wheel phase angle measurement point and a receipt point of the RF transmission, and the current content of the rolling window corresponds to the ABS data incremented between the TPM sensor wheel phase angle measurement point and the receipt point of the RF transmission; calculating a time of the TPM sensor wheel phase angle measurement point based on the time period between the TPM sensor wheel phase angle measurement point and the receipt point of the RF transmission; determining a relevant ABS data value at the time of the TPM sensor wheel phase angle measurement point from the current content of the rolling window of the ABS data based on the TPM sensor wheel phase angle measurement point over time; receiving further measurements that indicate the TPM sensor wheel phase angle at multiple points in time; determining the relevant ABS data for each of the plurality of ABS sensors for each of the multiple points in time for which the TPM sensor wheel phase angle is received; generating a histogram array for the relevant ABS data for each of the plurality of ABS sensors, the histogram array comprising a plot of the relevant ABS data and the TPM sensor wheel phase angle; applying a confidence interval to each histogram array of the relevant ABS data, wherein the confidence interval excludes outlier data; calculating a confidence interval (COIN) width value from each histogram array from which the outlier data has been excluded; and applying an auto-location algorithm to identify a specific location of the wheel based on determining which of the plurality of ABS sensors generates the histogram with the lowest COIN width value for the TPM sensor wheel phase angle and assigning one of the plurality of TPM sensors to a same wheel location as the ABS sensor having the lowest COIN width value. - View Dependent Claims (2, 3, 4, 5)
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6. A method for performing auto-location of a wheel in a vehicle, comprising:
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arranging a wheel unit to be associated with a wheel of the vehicle, the wheel unit comprising a tire pressure monitoring (“
TPM”
) sensor and a wheel phase angle sensor and the wheel unit transmitting TPM sensor parameters;arranging an antilock brake system (“
ABS”
) sensor to be associated with each wheel of the vehicle, the ABS sensor producing ABS data indicative of the wheel phase angle;upon rotation of the wheel, detecting with the wheel phase angle sensor a first time (T1) at a predetermined wheel phase angle; at a second time (T2), sending from the wheel unit a radio frequency (RF) transmission; at an electronic control unit (“
ECU”
), receiving the RF transmission;continually maintaining a rolling window of the ABS data associated with each wheel; storing a current content of the rolling window of ABS data for each wheel upon receipt of the RF transmission; calculating the first time (T1) based on a predetermined time delay (T2-T1) between the first time (T1) and the second time (T2); determining the ABS data at the first time (T1) for each wheel; generating a histogram array for the relevant ABS data for each of the ABS sensors, the histogram array comprising a plot of the relevant ABS data and the wheel phase angle; applying a confidence interval to each histogram array of the ABS data, wherein the confidence interval excludes outlier data; calculating a confidence interval (COIN) width value from each histogram array from which the outlier data has been excluded; identifying a location of the wheel whose COIN width value of ABS data is the smallest. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A wheel auto-location method, comprising:
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receiving, from one of a plurality of tire pressure monitoring (TPM) sensors, a radio frequency (RF) transmission indicating a TPM sensor wheel phase angle measurement point during rotation of a wheel and TPM sensor parameters; calculating a time of the TPM sensor wheel phase angle measurement point based on the RF transmission; maintaining a rolling window of ABS data for each of a plurality of ABS sensors and capturing a relevant rolling window of ABS data at the time of the TPM sensor wheel phase angle measurement point; monitoring the ABS data and detecting a rollback event which causes the ABS data to represent an irregular pattern; generating a histogram array for the relevant ABS data for each of the ABS sensors, the histogram array comprising the relevant ABS data and the wheel phase angle; applying a confidence interval to each histogram array of the ABS data, wherein the confidence interval excludes outlier data; calculating a confidence interval (COIN) width value from each histogram array from which the outlier data has been excluded; correlating the ABS data at the one-measurement point with a specific location of a wheel based on confidence interval (COIN) width analysis of the relevant rolling window of ABS data at the time of the TPM sensor wheel phase angle measurement point; and determining the specific location of the wheel where the TPM sensor parameters are assigned. - View Dependent Claims (15, 16, 17)
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18. A tire pressure monitoring system for performing auto-location of a wheel in a vehicle, comprising:
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a wheel unit to be associated with a wheel of the vehicle, the wheel unit comprising; a tire pressure monitoring (TPM) sensor that measures TPM sensor parameters of the wheel; and a wheel phase angle sensor that detects an angle of interest (P1) at a first time (T1); wherein the wheel unit transmits at the second time (T2) a radio frequency (RF) message comprising; an identification of the TPM sensor; and measured TPM sensor parameters; and an electronic control unit (“
ECU”
) of the vehicle in communication with the wheel unit and an ABS sensor; andcomputer program code operable in conjunction with the ECU of the vehicle, the ECU in communication with the wheel unit and the ABS sensor of the vehicle, wherein in response to the phase correlation data storage event trigger, the ECU is operable in response to the computer program code to execute instructions of; calculating the first time (T1) based on a predetermined time delay (T2-T1); storing a count of a number of ABS teeth which represents the number of ABS teeth that have passed each ABS sensor in a given period of time and is indicative of wheel phase angle based on a phase correlation data storage event trigger and determining the count of the number of ABS teeth or data at the first time (T1); generating a histogram array for the relevant ABS data for each of the ABS sensors, the histogram array comprising the relevant ABS data and the wheel phase angle; applying a confidence interval to each histogram array of the ABS data, wherein the confidence interval excludes outlier data; calculating a confidence interval (COIN) width value from each histogram array from which the outlier data has been excluded; correlating a location of the wheel with a location of the ABS sensor based on the confidence interval (COIN) width value calculated from the count of the number of ABS teeth at the first time (T1); and associating the TPM sensor parameters with the determined location of the wheel. - View Dependent Claims (19, 20)
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Specification