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EP-4071016-B1 - BRAKE SYSTEM AND METHOD OF MONITORING

EP4071016B1EP 4071016 B1EP4071016 B1EP 4071016B1EP-4071016-B1

Inventors

  • Sakhare, Sukrut
  • Adkins, Alex
  • Polmear, Chris
  • PHILPOTT, DANIEL

Dates

Publication Date
20260506
Application Date
20220330

Claims (15)

  1. A method of monitoring a brake system (10), the method comprising: obtaining data indicative of temperature of a first brake assembly (22) and temperature of a second brake assembly (22); determining a correlation value between temperature of the first brake assembly (22) and temperature of the second brake assembly (22), wherein the correlation value is a correlation coefficient that measures a linear correlation between the temperature of the first brake assembly and the temperature of the second brake assembly; determining whether the correlation value is less than a threshold correlation value; and conducting a mean temperature comparison when the correlation value is less than the threshold correlation value.
  2. The method of claim 1 wherein a first sensor (46) provides data indicative of the temperature of the first brake assembly (22) and a second sensor (46) provides data indicative of the temperature of the second brake assembly (22).
  3. The method of any preceding claim further comprising conducting a sensor check and excluding data indicative of temperature obtained from a sensor (46) that does not pass the sensor check, preferably further providing a notification via a communication device (90) when the sensor (46) does not pass the sensor check, and optionally, wherein the sensor check is conducted before determining the correlation value and/or the sensor check is conducted before obtaining data indicative of temperature.
  4. The method of any preceding claim wherein obtaining data indicative of temperature includes obtaining a predetermined number of data points indicative of the temperature of the first brake assembly (22) and obtaining a predetermined number of data points indicative of the temperature of the second brake assembly (22).
  5. The method of claim 2 wherein the method includes obtaining additional temperature data from the first sensor (46) and the second sensor (46) and recalculating the correlation value based on a rolling data window that includes the additional temperature data when the correlation value is not less than the threshold correlation value.
  6. The method of any preceding claim wherein an alert notification is provided when a mean temperature of the first brake assembly (22) is not sufficiently close to a mean temperature of the second brake assembly (22).
  7. The method of any preceding claim wherein an alert notification is provided when a mean temperature of the first brake assembly (22) is not sufficiently close to a mean temperature of the second brake assembly (22) for at least three overlapping data sets.
  8. The method of any preceding claim wherein an alert notification is provided when a mean temperature of the first brake assembly (22) is not sufficiently close to a mean temperature of the second brake assembly (22) for at least two consecutive nonoverlapping data sets.
  9. The method of claim 1 wherein: the step of obtaining data includes obtaining data indicative of temperature of a set of brake assemblies (22); the step of determining a correlation value includes determining correlation values between pairs of brake assemblies (22) based on the data; the step of determining whether the correlation value is less than the threshold correlation value includes determining whether any correlation value is less than the threshold correlation value; the step of conducting a mean temperature comparison includes conducting a mean temperature comparison when at least one correlation value is less than the threshold correlation value by (a) determining a candidate mean temperature of the brake assembly having the correlation value that is less than the threshold correlation value, (b) determining a group mean temperature of the brake assemblies (22) having correlation values that are not less than the threshold correlation value, and (c) determining whether the candidate mean temperature is sufficiently close to the group mean temperature; and providing an alert notification when the candidate mean temperature is not sufficiently close to the group mean temperature, and optionally wherein each member of the set of brake assemblies (22) is configured to brake a different wheel (30).
  10. The method of claim 9 wherein determining whether the candidate mean temperature is sufficiently close to the group mean temperature includes determining whether the candidate mean temperature is within a predetermined range with respect to the group mean temperature.
  11. The method of claim 9 or 10 wherein a sensor (46) is provided with each member of the set of brake assemblies (22) and a sensor check is conducted before determining correlation values, preferably correlation values are not determined for members of the set of brake assemblies (22) having sensors (46) that do not pass the sensor check and/or the group mean temperature does not include data from any sensor (46) that does not pass the sensor check.
  12. The method of any one of claims 9 through 11 wherein the alert notification is provided when the candidate mean temperature is not sufficiently close to the group mean temperature for three consecutive nonoverlapping periods of time.
  13. The method of any one of claims 9 through 12 wherein the set of brake assemblies (22) includes first and second brake assemblies (22, 22) that are provided with a first axle assembly (50) and third and fourth brake assemblies (22, 22) that are provided with a second axle assembly (50), preferably correlation values are determined for the first and second brake assemblies (22, 22), the first and third brake assemblies (22, 22), the first and fourth brake assemblies (22, 22), the second and third brake assemblies (22, 22), the second and fourth brake assemblies (22, 22), and the third and fourth brake assemblies (22, 22).
  14. A brake system (20) comprising: a control system (24) comprising a controller configured to: receive data indicative of temperature of a first brake assembly (22) and a temperature of a second brake assembly (22); determine a correlation value between temperature of the first brake assembly and the temperature of the second brake assembly; wherein the correlation value is a correlation coefficient that measures a linear correlation between the temperature of the first brake assembly and the temperature of the second brake assembly, determine whether the correlation value is less than a threshold correlation value; and conduct a mean temperature comparison when the correlation value is less than the threshold correlation value.
  15. A brake system (20) according to claim 14, wherein the brake system further comprises the first brake assembly (22) comprising a first sensor (46) that provides data indicative of temperature of the first brake assembly; the second brake assembly (22) comprising a second sensor that provides data indicative of temperature of the second brake assembly; wherein the first brake assembly and the second brake assembly provide the data to the controller.

Description

TECHNICAL FIELD This relates to a brake system for a vehicle and a method of monitoring the brake system. BACKGROUND A method of controlling a brake system of a vehicle is disclosed in U.S. Patent No. 9,199,624. JP6734863B2 discloses a method that compares brake temperatures and determines that a fault condition exists when the temperature of a brake deviates from an average temperature value by more than a threshold value. SUMMARY According to the invention, a method of monitoring a brake system is provided in claim 1. The method includes obtaining data indicative of temperature of a first brake assembly and temperature of a second brake assembly; determining a correlation value between temperature of the first brake assembly and temperature of the second brake assembly, wherein the correlation value is a correlation coefficient that measures a linear correlation between the temperature of the first brake assembly and the temperature of the second brake assembly; determining whether the correlation value is less than a threshold correlation value; and conducting a mean temperature comparison when the correlation value is less than the threshold correlation value. According to the invention, a corresponding brake system is provided in claim 14. A first sensor may provide data indicative of the temperature of the first brake assembly. A second sensor may provide data indicative of the temperature of the second brake assembly. The method may further comprise conducting a sensor check and excluding data indicative of temperature obtained from a sensor that does not pass the sensor check. The method may further comprise providing a notification via a communication device when the sensor does not pass the sensor check. The sensor check may be conducted before determining the correlation value. The sensor check may be conducted before obtaining data indicative of temperature. Obtaining data indicative of temperature may include obtaining a predetermined number of data points indicative of the temperature of the first brake assembly. Obtaining data indicative of temperature may include obtaining a predetermined number of data points indicative of the temperature of the second brake assembly. The method may include obtaining additional temperature data from the first sensor and the second sensor and recalculating the correlation value based on a rolling data window that includes the additional temperature data when the correlation value is not less than the threshold correlation value. The method may further comprise providing an alert notification when a mean temperature of the first brake assembly is not sufficiently close to a mean temperature of the second brake assembly. The alert notification may be provided when the mean temperature of the first brake assembly is not sufficiently close to the mean temperature of the second brake assembly for at least three overlapping data sets. The alert notification may be provided when the mean temperature of the first brake assembly is not sufficiently close to the mean temperature of the second brake assembly for at least two consecutive nonoverlapping data sets. The step of obtaining data may include obtaining data indicative of temperature of a set of brake assemblies. The step of determining a correlation value may include determining correlation values between pairs of brake assemblies based on the data. The step of determining whether the correlation value is less than the threshold correlation value may include determining whether any correlation value is less than the threshold correlation value. The step of conducting a mean temperature comparison includes conducting a mean temperature comparison when at least one correlation value is less than the threshold correlation value by (a) determining a candidate mean temperature of the brake assembly having the correlation value that is less than the threshold correlation value, (b) determining a group mean temperature of the brake assemblies having correlation values that are not less than the threshold correlation value, and (c) determining whether the candidate mean temperature is sufficiently close to the group mean temperature; and providing an alert notification when the candidate mean temperature is not sufficiently close to the group mean temperature. Each member of the set of brake assemblies may be configured to brake a different wheel. Determining whether the candidate mean temperature is sufficiently close to the group mean temperature may include determining whether the candidate mean temperature is within a predetermined range with respect to the group mean temperature. A sensor may be provided with each member of the set of brake assemblies. A sensor check may be conducted before determining correlation values. Correlation values may not be determined for members of the set of brake assemblies having sensors that do not pass the sensor check. The group mean temperature may not include data from any sens