Patent Description:
<CIT> discloses a method for determining a tread depth of a profile of a tire during operation of a vehicle having the tire, a control device for a vehicle for determining such a tread depth of a profile of a tire of the vehicle, and a system for a vehicle that comprises such a control device and at least one electronic wheel unit, wherein a determination of the tread depth based on a determined instantaneous dynamic wheel radius of a wheel of the vehicle having the tire and a determined instantaneous dynamic inner radius of the tire is provided. <CIT> discloses a method for estimating the degree of wear of a tire.

<CIT> discloses methods and apparatus for assessing tire health through monitoring an effective tire rolling radius.

<CIT> discloses a method for ascertaining a tread depth of a tire during operation of a vehicle having the tire, the vehicle transmitting adaptation data to a central data processor.

The invention is defined by the attached set of claims. Methods, systems, apparatuses, and computer program products for adjustment of indirectly determined values of a tire monitoring system are disclosed. In a particular embodiment, adjustment of indirectly determined values of a tire monitoring system includes a tire monitoring controller identifying an indirectly determined value associated with a tire. The tire monitoring controller also identifies one or more tire parameters from one or more direct measurement devices. The tire monitoring controller uses the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined value. The tire monitoring controller uses the adjusted indirectly determined value to indirectly determine a wear condition value for the tire.

In another embodiment, not falling under the scope of the claims, adjustment of indirectly determined values of a tire monitoring system includes a tire monitoring controller identifying an indirectly determined load value associated with a tire. The tire monitoring controller also identifies one or more tire parameters from one or more direct measurement devices. The tire monitoring controller uses the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined load value.

In another embodiment, not falling under the scope of the claims, adjustment of indirectly determined values of a tire monitoring system includes a tire monitoring controller identifying an indirectly determined grip value associated with a tire. The tire monitoring controller also identifies one or more tire parameters from one or more direct measurement devices. The tire monitoring controller uses the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined grip value.

In yet another embodiment, adjustment of indirectly determined values of a tire monitoring system includes a tire monitoring controller identifying an indirectly determined wear condition value associated with a tire. The tire monitoring controller also identifies one or more tire parameters from one or more direct measurement devices. The tire monitoring controller uses the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined wear condition value for the tire.

As explained above, the indirectly determined measurements of a tire monitoring system may be subject to inaccuracies due to the quality and accuracy of the base measurements. According to embodiments of the present invention, a tire monitoring system may improve the accuracy of the initial indirectly determined values (e.g., expansion value, load value, grip value, and wear condition value), by adjusting or compensating the initial indirectly determined values based on one or more tire parameters from a direct measurement device (e.g., a tire mounted sensor, a wheel mounted sensor, a valve mounted sensor). Improved accuracy in a tire monitoring system may increase the value and reliability of said system and its measurements. In addition to the advantage of improved accuracy, implementing the described tire monitoring system in vehicles with sensors and systems that are configured to generate tire parameters has the added advantage of achieving these improvements without additional sensor technology.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts of exemplary embodiments of the invention.

Whenever a singular form such as "a", "an" and "the" is used and using only a single element is neither explicitly nor implicitly defined as being mandatory, further examples may also use plural elements to implement the same functionality. It will be further understood that the terms "comprises", "comprising", "includes" and/or "including", when used, specify the presence of the stated features, integers, steps, operations, processes, acts, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, processes, acts, elements, components and/or any group thereof.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, the elements may be directly connected or coupled via one or more intervening elements. If two elements A and B are combined using an "or", this is to be understood to disclose all possible combinations, i.e. only A, only B, as well as A and B. An alternative wording for the same combinations is "at least one of A and B". The same applies for combinations of more than two elements.

Accordingly, while further examples are capable of various modifications and alternative forms, some particular examples thereof are shown in the figures and will subsequently be described in detail. However, this detailed description does not limit further examples to the particular forms described. Like numbers refer to like or similar elements throughout the description of the figures, which may be implemented identically or in modified form when compared to one another while providing for the same or a similar functionality.

Exemplary methods, apparatuses, and computer program products for adjustment of indirectly determined values of a tire monitoring system in accordance with the present disclosure are described with reference to the accompanying drawings, beginning with <FIG>. For further explanation, <FIG> sets forth a diagram of a system <NUM> for adjustment of indirectly determined values of a tire monitoring system. The system of <FIG> includes a motor vehicle <NUM> equipped with four tires <NUM> (two are illustrated). The invention is not limited to such a motor vehicle. The invention can also be used in connection with any number of tires, including a motorcycle having only one front tire and one rear tire. In the example of <FIG>, each of the tires is equipped with a tire sensor <NUM>. A tire sensor may be a tire mounted sensor (TMS), a valve mounted sensor (VMS), or a wheel rim mounted sensor.

While the embodiment of <FIG> shows two tires each equipped with a tire sensor <NUM>, it will be understood that as few as one, and as many as all, of the tires <NUM> of the vehicle <NUM> may include a tire sensor <NUM>. The vehicle of <FIG> further includes a vehicle control system (VCS) <NUM> that controls various components and systems within a vehicle. In a particular embodiment, the VCS (<NUM>) includes a plurality of electronic control units (ECUs) that are configured to control one or more vehicle subsystems. Commonly referred to as the vehicle's "computers", an ECU may be a central control unit or may refer collectively to one or more vehicle subsystem control units, such as an Engine Control Module (ECM), a Powertrain Control Module (PCM), a Transmission Control Module (TCM), a Brake Control Module (BCM), a Central Timing Module (CTM), a General Electronic Module (GEM), or a Suspension Control Module (SCM). In an embodiment according to the present disclosure, the VCS <NUM> includes a BCM that includes an Antilock Braking System (ABS) and an Electronic Stability Program (ESP). Alternatively, the VCS <NUM> may comprise a Telematics Control Unit (TCU) independent of vehicle-based sensors (e.g., an aftermarket system).

Each tire sensor <NUM> is equipped with a wireless transceiver for bidirectional wireless communication with the VCS <NUM>, as will be described in more detail below. The VCS is similarly equipped with a wireless transceiver for bidirectional wireless communication with each of the tire sensors <NUM>, as will be described in more detail below. The bidirectional wireless communication may be realized by low power communication technology such as Bluetooth Low Energy or other low power bidirectional communication technology that is intended to conserve energy consumed. Alternatively, each tire sensor <NUM> may include a unidirectional transmitter configured to transmit signals to the VCS <NUM>.

Each vehicle system may include sensors (<NUM>) used to measure and communicate vehicle operating conditions. For example, the ABS may include wheel speed sensors on the wheelbase used to measure wheel speed. The ESP subsystem may include yaw rate sensors configured to measure the yaw-induced acceleration of the vehicle when the vehicle is maneuvering a curve. Readings from such sensors <NUM> may be provided to the VCS <NUM>, which may provide parameters based on these readings to the tire sensor <NUM>. The vehicle <NUM> may further include a transceiver <NUM> communicatively coupled to the VCS <NUM> for cellular terrestrial communication, satellite communication, or both.

The arrangement of devices making up the exemplary system illustrated in <FIG> are for explanation, not for limitation. Data processing systems useful according to various embodiments of the present disclosure may include additional servers, routers, other devices, and peer-to-peer architectures, not shown in <FIG>, as will occur to those of skill in the art. Networks in such data processing systems may support many data communications protocols, including for example TCP (Transmission Control Protocol), IP (Internet Protocol), Bluetooth protocol, Near Field Communication, Controller Area Network (CAN) protocol, and others as will occur to those of skill in the art. Various embodiments of the present disclosure may be implemented on a variety of hardware platforms in addition to those illustrated in <FIG>.

For further explanation, <FIG> illustrates a block diagram of a tire having a tire sensor <NUM>. Typically, the tire sensor <NUM> is mounted on to a valve or tire, or otherwise coupled to, an internal surface of the tire <NUM>, especially on the inner liner of the tire above the tread. As the tire <NUM> rotates, the portion that engages with the road surface at any given time is flattened. The flattened portion is known as the tire footprint or, interchangeably, contact patch. One or more features of the tire <NUM>, in particular the length of the contact patch (typically measured in the direction of travel of the vehicle), may be used, for example, as an indication of the load on the tire <NUM>. Electrical signals produced by the tire sensor <NUM> can be used to measure the contact patch, in particular its length. It will be understood that one or more of the tires <NUM> of the vehicle <NUM> may each include a tire sensor <NUM> for providing one or more target signals in respect of which pulse width measuring is performed.

In another embodiment, the signals from the tire sensor may be used to calculate peak radial displacement (PRD). PRD is the peak magnitude of radial deformation at the tire contact patch. Both CPL and PRD are influenced by tire load and pressure, and, accordingly, tires may be characterized by comparing the magnitude of CPL or PRD with varying pressure and load. Characteristic equations may be stored, for example, in the TMS (<NUM>) of <FIG> or in the vehicle control unit (<NUM>) of <FIG>. CPL may be estimated by measuring the time at which the radial acceleration is returning to and is at zero g. This time is then expressed as a quotient/ratio of the time for a complete rotation, and the CPL is derived from its ratio of the known tire circumference or tire radius. In order to determine the PRD, the radial accelerometric signal may be integrated twice with respect to time. For load estimation, either of these two methods can be used independently.

For further explanation, <FIG> illustrates a reference diagram of a tire <NUM> in accordance with the present disclosure. As used in this disclosure, the z-axis of the tire <NUM> is the direction of radial force during rotation, the y-axis of the tire is the direction of lateral force during rotation, and the x-axis of the tire <NUM> is the direction of tangential force during rotation. The angular speed of rotation is represented by ω, and is also referred to herein as wheel speed.

For further explanation, <FIG> sets forth a diagram of an exemplary vehicle control system (VCS) <NUM> for adjustment of indirectly determined values of a tire monitoring system according to embodiments of the present disclosure. The VCS <NUM> includes a controller <NUM> coupled to a memory <NUM>. The controller <NUM> is configured to obtain sensor readings related to vehicle operating conditions, as well as data from sources external to the vehicle, and provide configuration parameters to a tire sensor, such as tire sensor <NUM> (see <FIG>). The controller <NUM> may include or implement a microcontroller, an Application Specific Integrated Circuit (ASIC), a digital signal processor (DSP), a programmable logic array (PLA) such as a field programmable gate array (FPGA), or other data computation unit in accordance with the present disclosure. The sensor readings and data, as well as tire feature data received from the tire sensor, may be stored in the memory <NUM>. The memory <NUM> may be a non-volatile memory such as flash memory. For example, the VCS <NUM> may obtain vehicle operating condition data such as sensor readings from sensors on-board the vehicle.

For bidirectional wireless communication with a tire sensor, the VCS <NUM> includes a tire sensor transceiver <NUM> coupled to the controller <NUM>. In one embodiment, the tire sensor transceiver <NUM> is a Bluetooth Low Energy transmitter-receiver. In other embodiments, the tire sensor transceiver <NUM> may be other types of low power bidirectional communication technology that is intended to conserve energy consumed in the tire sensor. The VCS <NUM> may further include a transceiver <NUM> for cellular terrestrial communication, satellite communication, or both.

The VCU <NUM> also includes a Global Positioning System (GPS) receiver <NUM> configured to communicate with one or more GPS satellites in order to determine a vehicle location, speed, direction of movement, etc. The VCU <NUM> also includes an inertial measurement unit (IMU) <NUM> configured to measures a vehicle's specific force, angular rate, and/or orientation using a combination of accelerometers, gyroscopes, and/or magnetometers.

The VCS <NUM> may further comprise a controller area network (CAN) interface <NUM> for communicatively coupling vehicle sensors and devices to the controller <NUM>. In the example of <FIG>, the CAN interface <NUM> couples a wheel speed sensor <NUM> and other sensors <NUM>, to the controller <NUM>. The wheel speed sensor <NUM> measures the rotational angular speed of the wheel, e.g., in radians per second. The wheel speed sensor <NUM> may transmit readings to the controller <NUM> via the CAN interface <NUM>.

The memory <NUM> of the VCS <NUM> includes a tire monitoring controller <NUM> configured for adjustment of indirectly determined values of a tire monitoring system. In a particular embodiment, the tire monitoring controller <NUM> includes computer program instructions that when executed by the controller <NUM> cause the controller <NUM> to carry out the steps of: identifying an indirectly determined value; identifying one or more tire parameters from one or more direct measurement devices; using the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined value; and using the adjusted indirectly determined value to indirectly determine a wear condition value for the tire.

In a second embodiment, the tire monitoring controller <NUM> includes computer program instructions that when executed by the controller <NUM> cause the controller <NUM> to carry out the steps of: identifying an indirectly determined load value; identifying one or more tire parameters from one or more direct measurement devices; and using the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined load value.

In a third embodiment, the tire monitoring controller <NUM> includes computer program instructions that when executed by the controller <NUM> cause the controller <NUM> to carry out the steps of: identifying an indirectly determined grip value; identifying one or more tire parameters from one or more direct measurement devices; and using the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined grip value.

In a fourth embodiment, the tire monitoring controller <NUM> includes computer program instructions that when executed by the controller <NUM> cause the controller <NUM> to carry out the steps of: identifying an indirectly determined wear condition value; identifying one or more tire parameters from one or more direct measurement devices; and using the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined wear condition value for the tire.

In a particular embodiment, the memory <NUM> may also store indirectly determined values <NUM> (e.g., expansion values; load values, grip values, and wear condition values). As will be explained below, the tire monitoring controller may generate these indirectly determined values or alternatively may receive these indirectly determined values from another vehicle component.

For further explanation, <FIG> sets forth a diagram of an embodiment of a Telematics Control Unit (TCU) <NUM> (e.g., an aftermarket system not directly coupled to vehicle-based sensors. The TCU <NUM> includes a controller <NUM>, memory <NUM>, and tire sensor transceiver <NUM> performing similar functions as described above with respect to the VCS <NUM> <FIG>. The TCU <NUM> also includes a Global Positioning System (GPS) receiver <NUM> configured to communicate with one or more GPS satellites in order to determine a vehicle location, speed, direction of movement, etc. The TCU <NUM> also includes an inertial measurement unit (IMU) <NUM> configured to measures a vehicle's specific force, angular rate, and/or orientation using a combination of accelerometers, gyroscopes, and/or magnetometers. The TCU <NUM> also includes an on-board diagnostics (OBD) interface <NUM> for coupling the TCU <NUM> to one or more on-board diagnostic devices of a vehicle. The TCU <NUM> may receive power via a power interface (<NUM>) couplable to a vehicle power bus.

The memory <NUM> of the TCU <NUM> includes a tire monitoring controller <NUM> includes computer program instructions that when executed by the controller <NUM> cause the controller to carry out the steps of: identifying an indirectly determined value; identifying one or more tire parameters from one or more direct measurement devices; using the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined value; and using the adjusted indirectly determined value to indirectly determine a wear condition value for the tire.

For further explanation, <FIG> sets forth a diagram of an exemplary tire sensor <NUM> for determining tread depth according to embodiments of the present disclosure. The tire sensor <NUM> includes a processor <NUM>. The processor may include or implement a microcontroller, an Application Specific Integrated Circuit (ASIC), a digital signal processor (DSP), a programmable logic array (PLA) such as a field programmable gate array (FPGA), or other data computation unit in accordance with the present disclosure.

The tire sensor <NUM> of <FIG> also includes a memory <NUM> coupled to the processor <NUM>. The memory may store signal capture configuration parameters <NUM> and other data received from the VCS <NUM>. The memory <NUM> may store a sampling rates table <NUM> of sampling rates each corresponding to a specific parameter value, e.g., a wheel speed or rotational period of the tire. The memory <NUM> may also store a windowing function table <NUM> of windowing functions each corresponding to a specific parameter value, e.g., a wheel speed or rotational period of the tire. The memory <NUM> may also store a filter table <NUM> filter frequency bands, each corresponding to a specific parameter value, e.g., a wheel speed or rotational period of the tire. The memory <NUM> may also store accelerometric data <NUM>, including a raw digital signal sampled from the accelerometer <NUM> by the ADC <NUM> and a processed accelerometric waveform processed by the processor <NUM>. The memory <NUM> may also store tire feature data <NUM>, such as a CPL measurement or a PRD measurement extracted by the processor <NUM>. The memory <NUM> may also store FFT or Goertzel algorithm configurations <NUM>.

For bidirectional wireless communication with the VCS <NUM>, the tire sensor <NUM> of <FIG> includes a transceiver <NUM> coupled to the processor <NUM>. In one embodiment, the transceiver <NUM> is a Bluetooth Low Energy transmitter-receiver. In other embodiments, the transceiver <NUM> may be other types of low energy bidirectional communication technology that is intended to conserve energy consumed in the tire sensor <NUM>. The tire sensor <NUM> transmits extracted tire feature data, such as acceleration profiles, PRD, and CPL, to the VCS <NUM> via the transceiver <NUM>. In an alternative embodiment, the tire sensor <NUM> includes a unidirectional transmitter configured to transmit data to the VCS <NUM>.

The accelerometer <NUM> of <FIG> may also be an acceleration sensor, an accelerometric device, a shock sensor, a force sensor, a microelectromechanical systems (MEMs) sensor, or other device that is similarly responsive to acceleration magnitude and/or to changes in acceleration or tire deformation. For example, an accelerometer senses acceleration in the radial plane (z-plane) and outputs an electric pulse signal responsive to sensed acceleration. In an embodiment, the accelerometer <NUM> is configurable with an accelerometer range, a wheel speed parameter, or other vehicle parameter provided by the VCS <NUM>. For example, g-offset can be determined via wheel speed sensor or another vehicle parameter and used to capture and process signals faster. Accelerometers may have a selectable range of forces they can measure. These ranges can vary from ±<NUM> up to ±<NUM>. An example range of an accelerometer is ± <NUM>. The accelerometer range may be configured based on wheel speed, for example, ± <NUM> at a low speed, ±<NUM> at a medium speed, and ±<NUM> at a high speed. Typically, the smaller the range, the more sensitive the readings will be from the accelerometer.

The tire sensor <NUM> of <FIG> also includes an analog to digital converter (ADC) <NUM> that receives the electric pulse signals from the accelerometer <NUM> and samples them according to a sampling rate. The ADC <NUM> converts the raw analog signals received from the accelerometer <NUM> into a raw digital signal that is suitable for digital signal processing. The sample rate of the ADC <NUM> may be configured via wheel speed from the wheel speed sensor or another vehicle-provided parameter from a vehicle sensor.

The tire sensor <NUM> of <FIG> also includes a battery <NUM> connected to a power bus (not shown) to power the transceiver <NUM>, the processor <NUM>, the ADC <NUM>, the accelerometer <NUM>, and the memory <NUM>. One skilled in the art that the tire sensor <NUM> may be powered by other sources alternative to or in addition to the battery <NUM>, such as an energy harvester or other power source.

In some embodiments, the tire sensor <NUM> may be configured to calculate tread depth while driving. For example, the tire sensor <NUM> may determine the CPL of a tire based on data from the accelerometer <NUM>. In this example, CPL may be estimated by measuring the time at which the radial acceleration is returning to and is at zero g. This time is then expressed as a quotient/ratio of the time for a complete rotation, and the CPL is derived from its ratio of the known tire expansion.

The memory <NUM> of the tire sensor <NUM> includes a tire monitoring controller <NUM> includes computer program instructions that when executed by the controller <NUM> cause the controller <NUM> to carry out the steps of: identifying an indirectly determined value; identifying one or more tire parameters from one or more direct measurement devices; using the one or more tire parameters from the one or more direct measurement devices to adjust the indirectly determined value; and using the adjusted indirectly determined value to indirectly determine a wear condition value for the tire.

In a particular embodiment, the memory <NUM> may also store indirectly determined values <NUM> (e.g., expansion values; load values, grip values, and wear condition values). As will be explained below, the tire monitoring controller may generate these indirectly determined values or alternatively may receive these indirectly determined values from another vehicle component. In the example of <FIG>, the memory <NUM> also includes tire data <NUM> that includes identifications of tires.

For further explanation, <FIG> sets forth a flow chart illustrating an exemplary method for adjustment of indirectly determined values of a tire monitoring system according to embodiments of the present disclosure. The method of <FIG> includes identifying <NUM>, by a tire monitoring controller <NUM>, an indirectly determined value <NUM> associated with a tire. As explained above, a tire monitoring controller according to embodiments of the present invention may be implemented in a variety of vehicle components. For example, the tire monitoring controller <NUM> may be: the example tire monitoring controller <NUM> within the Vehicle Control System <NUM> of <FIG>, the example tire monitoring controller <NUM> within the Telematics Control Unit <NUM> of <FIG>, and the tire monitoring controller <NUM> within the tire sensor <NUM> of <FIG>.

An indirectly determined value is an estimate, inference, or other indirectly determined indication of a condition of a tire (e.g., a degree of expansion of a tire). Examples of indirectly determined values may include but are not limited to tire radius values, tire circumference values, and tire diameter values.

Identifying <NUM>, by a tire monitoring controller <NUM>, an indirectly determined value <NUM> associated with a tire may be carried out by determining an identification for a particular tire; and selecting, from a plurality of indirectly determined values, an indirectly determined value having a tag or identification associated with an identification for the particular tire.

In a particular embodiment, the indirectly determined value may be generated by another vehicle component other than the tire monitoring controller <NUM>. In this embodiment, a tire monitoring controller may receive one or more indirectly determined values from another vehicle component. For example, a tire monitoring controller in a tire sensor may receive indirectly determined values generated by a vehicle control system (VCS).

In another embodiment, the indirectly determined value may be generated by the tire monitoring controller <NUM>. In this embodiment, the tire monitoring controller may indirectly determine a value and store the indirectly determined value in a memory or storage location accessible by the tire monitoring controller.

In addition, the method of <FIG> includes identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> from one or more direct measurement devices. A direct measurement device is a device that is configured to directly measure a tire parameter. Tire parameters in the example of <FIG> are values that impact the condition (e.g., circumference) of the tire and therefore may be used to compensate or adjust an indirectly determined value of the tire. Examples of tire parameters include but are not limited to speed values, tire stiffness parameters, tire max load rating values, max pressure rating value, tire age value, distance traveled value, and others as will occur to those of skill in the art. Identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> may be carried out by requesting and receiving one or more tire parameters from one or more components of the vehicle including a tire sensor, vehicle sensors, a VCS, and a TCU. The tire monitoring controller may have access to memory or a storage location that store the one or more tire parameters. Alternatively, identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> may be carried out by directly measuring one or more of the tire parameters. In another embodiment, identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> may be carried out by accessing the tire parameters.

The method of <FIG> also includes using <NUM>, by the tire monitoring controller <NUM>, the one or more tire parameters <NUM> to adjust the indirectly determined value <NUM>. Using <NUM>, by the tire monitoring controller <NUM>, the one or more tire parameters <NUM> to adjust the indirectly determined value <NUM> may be carried out by applying one or more algorithms or indexes that define a relationship between the one or more tire parameters and an expansion value. For example, each tire parameter may have a defined relationship with an expansion value. An index or algorithm may codify that relationship, such that the tire monitoring controller may use the index or algorithm to generate an adjusted indirectly determined value.

In a particular embodiment, the one or more tire parameters <NUM> include a speed value that indicates a measured vehicle speed or rotational speed of the tire. For example, as a tire rotates across a road surface, the tire is subject to centrifugal force. This centrifugal force acts on the tire in a manner such that the tire is "pulled" in a direction that is outwards from the center of the wheel hub (in the radial plane), having a similar effect as an increase in pressure but with a lesser degree of magnitude. This centrifugal force is proportional to the square of the rotational speed of the tire or the square of the linear velocity of the tire or the vehicle. The tire monitoring controller may use an index or algorithm that defines the relationship between speed values and circumference expansion. In that respect, the additional input of the speed value may be indicated by a measured vehicle speed or tire rotational speed. For example, tire rotational speed may be measured from either the vehicle wheel speed sensors or measured by a tire sensor (e.g., tire mounted sensor (TMS), valve mounted sensor (VMS), or wheel rim sensor). In this example, the wheel speed sensors or tire sensors may communicate the speed value to a vehicle-based system by radio frequency, Bluetooth low energy (BLE), or other means.

In a particular embodiment, the one or more tire parameters <NUM> include a distance traveled value that indicates a distance that a tire has traveled. As a tire travels and becomes worn down, indirectly determined values, such as an expansion value, may be impacted. The tire monitoring controller may use an index or algorithm that defines the relationship between distance traveled values and circumference size. In that respect, the additional input of the distance traveled value may be indicated by a rotations count or miles count. For example, distance traveled value may be measured from either the vehicle sensors or a vehicle-based system (e.g., VCS).

In another embodiment, the one or more tire parameters <NUM> include one or more tire stiffness parameters. The magnitude of a tire expansion and hence circumference change due to pressure and speed is dependent on a tire's characteristic stiffness. To determine the stiffness coefficients for a given tire model, various loads and pressures can be applied to the tire using a flat track, a drum tester, a static test, or through a simulation or model. The measurements can then be used to solve for the coefficients of the polynomial function. For example, assume a polynomial function f(x, y) = p<NUM> + p<NUM>x + p<NUM>y + p<NUM>x<NUM> + p<NUM>xy, where x is the inflated tire pressure, y is the applied load, and p00, p10, p01, p20, and p<NUM> are the stiffness coefficients. The tire coefficients may then be determined by solving for the polynomial function using the test samplings. It is understood that a higher order polynomial function may also be used, resulting in additional polynomial coefficients. The stiffness coefficients may then be stored in a database or other data structure that associates a tire model identifier (e.g., a model number) with a particular set of stiffness coefficients. The tire monitoring controller may adjust the load value by using an index or algorithm that defines the relationship between the tire stiffness parameters and circumference expansion.

These coefficients are indicative of the relationship between the vertical compression load at an applied pressure and the resultant tire radial displacement or deformation at the ground contact surface. Additionally, these stiffness coefficients are a gauge of the relationship between the centrifugal radial forces subjected on the tire, which are applicable to pressure and speed, and the degree of resulting circumferential expansion. In a particular embodiment, the tire stiffness coefficients may be expressed as one or more tire stiffness parameters. The tire stiffness parameters may be stored in various locations (e.g., cloud, vehicle ECU, or tire sensor) for access by the tire monitoring controller. The tire monitoring controller may use an index or algorithm that defines the relationship between tire coefficient parameters and circumference expansion to adjust the initial indirectly determined values.

Furthermore, the method of <FIG> includes using <NUM>, by the tire monitoring controller <NUM>, the adjusted indirectly determined value <NUM> to indirectly determine a wear condition value <NUM> for the tire. A wear condition value may indicate tread depth, loss of tread, tread wear or any other indication of wear. Using <NUM>, by the tire monitoring controller <NUM>, the adjusted indirectly determined value <NUM> to indirectly determine a wear condition value <NUM> for the tire may be carried out by applying one or more algorithms or indexes that define a relationship between the adjusted indirectly determined value to a wear condition value. An index or algorithm may define the relationship between the circumference expansion and the wear condition value.

As explained above, a tire monitoring controller that uses measurements associated with a tire to infer or indirectly determine an expansion value for a tire may be susceptible to inaccuracies due to the quality and accuracy of the measurements and how those measurements were generated. By adjusting the expansion value based on one or more tire parameters, the accuracy of the expansion value may be improved for a tire monitoring system. Using a more accurate expansion value may allow a tire monitoring system to indirectly determine a wear condition value of the tire more accurately. Increasing the accuracy of indirect measurements for a wear condition value of a tire may increase the value of the system to a user or vehicle control system. For vehicles with sensors and systems that are configured to capture tire parameters, another advantage of implementing the tire monitoring system of the present invention is that the accuracy of the wear condition value determination may be achieved without additional sensor technology.

For further explanation, <FIG> sets forth a flow chart illustrating an exemplary method of adjustment of indirectly determined values of a tire monitoring system according to embodiments of the present disclosure. The method of <FIG> is similar to the method of <FIG> in that the method of <FIG> includes all of the elements of <FIG>. However, the method of <FIG> includes additional elements that the tire monitoring controller performs for indirect determination of an indirectly determined value (e.g., an expansion value). Specifically, the method of <FIG> includes determining <NUM>, by the tire monitoring controller <NUM>, one or more measurements <NUM> associated with the tire.

A measurement <NUM> may be any value useful for inferring, estimating, or otherwise indirectly determining an initial indirectly determined value (e.g., an expansion value) of the tire. Examples of the measurements <NUM> include but are not limited to a tire pressure measurement, a tire temperature, an outside temperature, an elapsed time from a start of a drive. Continuing with this embodiment, the tire monitoring controller may receive the one or more measurements from one or more components of the vehicle including vehicle sensors, vehicle control systems (VCS), Electronic Control Systems (ECS), and Telematics Control Units (TCU). For example, the tire monitoring controller may request and receive the one or more measurements from one or more components of the vehicle. As another example, the tire monitoring controller may be configured to periodically receive the one or more measurements from the one or more components without having to specifically request the one or more measurements. In another example, the one or more components of the vehicle may store the one or more measurements in a memory or storage system that the tire monitoring controller may access. Determining <NUM>, by the tire monitoring controller <NUM>, one or more measurements <NUM> associated with the tire may be carried out by selecting from a plurality of measurements the one or more measurements, to use for indirectly determining the expansion value.

In addition, the method of <FIG> also includes using <NUM>, by the tire monitoring controller <NUM>, the one or more measurements <NUM> to indirectly determine the indirectly determined value <NUM>. Using <NUM> the one or more measurements <NUM> to indirectly determine a value <NUM> for the tire may be carried out by applying one or more algorithms or indexes that define a relationship between the one or more measurements and an expansion value. For example, a general rule is that as a tire is inflated from zero pressure, the tire will expand, and its expansion will increase. A tire monitoring controller may utilize an index or algorithm that indicates or generates an expansion value for a given tire pressure and specific of the type of the tire. In a particular embodiment, the one or more measurements may be used in the index or algorithm to indirectly determine an expansion value. Tire temperature, tire pressure, or outside air temperature are examples of other factors that have a general relationship to tire expansion size. For example, the tire monitoring controller may infer an expansion value for the tire based on a combination of tire parameters, such as a temperature measurement, a tire pressure, and the specifics of the type of the tire.

For further explanation, <FIG> sets forth a flow chart illustrating an exemplary method of adjustment of indirectly determined values of a tire monitoring system according to embodiments not falling under the scope of the claims. The method of <FIG> includes identifying <NUM>, by a tire monitoring controller <NUM>, an indirectly determined load value <NUM> associated with a tire. As explained above, a tire monitoring controller according to embodiments of the present invention may be implemented in a variety of vehicle components. For example, the tire monitoring controller <NUM> may be: the example tire monitoring controller <NUM> within the Vehicle Control System <NUM> of <FIG>, the example tire monitoring controller <NUM> within the Telematics Control Unit <NUM> of <FIG>, and the tire monitoring controller <NUM> within the tire sensor <NUM> of <FIG>.

An indirectly determined load value is an estimate, inference, or other indirectly determined indication of the amount of tire compression during loading effects. Identifying <NUM>, by a tire monitoring controller <NUM>, an indirectly determined load value <NUM> associated with a tire may be carried out by determining an identification for a particular tire; and selecting, from a plurality of indirectly determined load values, an indirectly determined load value having a tag or identification associated with an identification for the particular tire.

In a particular embodiment, the indirectly determined load value may be generated by another vehicle component other than the tire monitoring controller <NUM>. In this embodiment, a tire monitoring controller may receive one or more indirectly determined load values from another vehicle component. For example, a tire monitoring controller in a tire sensor may receive indirectly determined load values generated by a vehicle control system (VCS).

In another embodiment, the indirectly determined load value may be generated by the tire monitoring controller <NUM>. In this embodiment, the tire monitoring controller may indirectly determine a load value and store the indirectly determined load value in a memory or storage location accessible by the tire monitoring controller.

In addition, the method of <FIG> also includes identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> from one or more direct measurement devices. A direct measurement device is a device that is configured to directly measure a tire parameter. Tire parameters are values that impact the load value and therefore may be used to compensate an indirect determination of an initial load value. Identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> from the one or more direct measurement devices may be carried out by requesting and receiving one or more tire parameters from one or more components of the vehicle including a tire sensor, vehicle sensors, a VCS, and a TCU. The tire monitoring controller may have access to memory or a storage location that stores the one or more tire parameters. Alternatively, identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> may be carried out by directly measuring one or more of the tire parameters.

The method of <FIG> also includes using <NUM>, by the tire monitoring controller <NUM>, the one or more tire parameters <NUM> to adjust the indirectly determined load value <NUM>. Using <NUM>, by the tire monitoring controller <NUM>, the one or more tire parameters <NUM> to adjust the indirectly determined load value <NUM> may be carried out by applying one or more algorithms or indexes that define a relationship between the one or more tire parameters and the initial load value. For example, each tire parameter may have a defined relationship with a load value. An index or algorithm may codify that relationship, such that the tire monitoring controller may adjust a load value based on the tire parameter.

In a particular embodiment, the one or more tire parameters <NUM> include a tire parameter that is a speed value indicating a measured vehicle speed or rotational speed of the tire. The speed of the tires and the tire stiffness values impact the centrifugal forces acting on the interior of the tire, which impact deformation of the tire under a load. For example, as a tire rotates across a road surface, the tire is subject to centrifugal force. This centrifugal force acts on the tire in a manner such that the tire is "pulled" in a direction that is outwards from the center of the wheel hub (in the radial plane), having a similar effect as an increase in pressure but with a lesser degree of magnitude. This centrifugal force is proportional to the square of the rotational speed of the tire or the square of the linear velocity of the tire or the vehicle. The tire monitoring controller may use an index or algorithm that defines the relationship between speed values, tire stiffness values, and load values. In that respect, the additional input of the speed value may be indicated by a measured vehicle speed or tire rotational speed. For example, tire rotational speed may be measured from either the vehicle wheel speed sensors or measured by a tire sensor (e.g., tire mounted sensor (TMS), valve mounted sensor (VMS), or wheel rim sensor). In this example, the wheel speed sensors or tire sensors may communicate the speed value to a vehicle-based system by radio frequency, Bluetooth low energy (BLE), or other means.

In another embodiment, the one or more tire parameters <NUM> include a tire stiffness parameter. As explained above, the magnitude of the expansion due to pressure and speed is dependent on a tire's characteristic stiffness. Differences in tire expansion may impact the deformation of the tire under a load. To determine the stiffness coefficients for a given tire model, various loads and pressures can be applied to the tire using a flat track, a drum tester, a static test, or through a simulation or model. The measurements can then be used to solve for the coefficients of the polynomial function. These coefficients are indicative of the relationship between the vertical compression load at an applied pressure and the resultant tire radial displacement or deformation at the ground contact surface. Additionally, these stiffness coefficients are a gauge of the relationship between the centrifugal radial forces subjected on the tire, which are applicable to pressure and speed, and the degree of resulting circumferential expansion. In a particular embodiment, the tire stiffness coefficients may be expressed as one or more tire stiffness parameters. The tire stiffness parameters may be stored in various locations (e.g., cloud, vehicle ECU, or tire sensor) for access by the tire monitoring controller. The tire monitoring controller may use an index or algorithm that defines the relationship between tire coefficient parameters and load values to adjust the load values.

In another embodiment, the one or more tire parameters <NUM> include a contact patch length (CPL) measurement associated with a length of the tire contact patch with the road surface. A tire sensor may generate a CPL measurement by using a radial acceleration or tangential acceleration (x plane) measurement. In this example, the tire sensor may generate a radial acceleration measurement using an accelerometer, an acceleration sensor, an accelerometric device, a shock sensor, a force sensor, a microelectromechanical systems (MEMs) sensor, or other devices that are similarly responsive to acceleration magnitude and/or to changes in acceleration. For example, an accelerometer senses acceleration in the radial plane (z-plane) (see <FIG>). The characteristic of the accelerometric waveform exhibits a centrifugal offset and region where the magnitude momentarily drops to zero during the time when the zone where the sensor is mounted is at tire/ground contact position. That is, CPL may be calculated by measuring the time at which the radial acceleration is returning to and is at zero g. This measurement is repeated for rotations of the tire. The radial acceleration signal may then be conditioned to make processing easier by isolating each strike in the acceleration profile, low-pass filtering the waveform, inverting the waveform, and normalizing the waveform for speed. CPL measurements may be influenced by tire load and pressure, and, accordingly, tires may be characterized by comparing the magnitude of CPL with varying pressure and load. Characteristic equations may be stored, for example, in the TMS (<NUM>) of <FIG> or in the vehicle control unit (<NUM>) of <FIG>.

In another embodiment, the one or more tire parameters <NUM> include a peak radial displacement (PRD) measurement associated with a peak magnitude of radial deformation at the tire contact patch. As with CPL measurements, a tire sensor may generate a PRD measurement by using a radial acceleration measurement. In a particular embodiment, the tire sensor determines the PRD by integrating the radial accelerometric signal twice with respect to time. Both CPL and PRD are influenced by tire load and pressure, and, accordingly, tires may be characterized by comparing the magnitude of CPL or PRD with varying pressure and load. Characteristic equations may be stored, for example, in the TMS or in a vehicle control unit.

In another embodiment, the one or more tire parameters <NUM> include a determination of tire load. The determination of tire load may be value that is calculated by some vehicle component (e.g., tire sensor, vehicle sensor, VCS, TCU) using a tire pressure value and a CPL measurement or a PRD measurement. For example, a tire monitoring controller may determine the load for a tire using a stored characteristic equation for determining load based on the CPL/PRD and other factors, such as tire pressure, tire speed, tire temperature, etc. Using a load determination based on PRD or CPL to adjust an initial load value may increase the accuracy of the final adjusted load value.

In a particular embodiment, the tire monitoring controller may use a plurality of tire parameters (e.g., speed values, tire stiffness parameters, contact path length, peak radial deformation, load as determined by CPL/PRD) to adjust the initial load value.

For further explanation, <FIG> sets forth a flow chart illustrating an exemplary method of adjustment of indirectly determined values of a tire monitoring system according to embodiments not falling under the scope of the claims. The method of <FIG> is similar to the method of <FIG> in that the method of <FIG> includes all of the elements of <FIG>. However, the method of <FIG> includes additional elements that the tire monitoring controller performs for indirect determination of a load value. Specifically, the method of <FIG> includes determining <NUM>, by the tire monitoring controller <NUM>, one or more measurements <NUM> associated with the tire.

A measurement <NUM> may be any value useful for inferring, estimating, or otherwise indirectly determining an initial load value of the tire. Examples of the measurements <NUM> include but are not limited to height of tires or axels (axle height sensors) and a tire pressure measurement. Continuing with this embodiment, the tire monitoring controller may receive the one or more measurements from one or more components of the vehicle including vehicle sensors, vehicle control systems (VCS), Electronic Control Systems (ECS), and Telematics Control Units (TCU). For example, the tire monitoring controller may request and receive the one or more measurements from one or more components of the vehicle. As another example, the tire monitoring controller may be configured to periodically receive the one or more measurements from the one or more components without having to specifically request the one or more measurements. In another example, the one or more components of the vehicle may store the one or more measurements in a memory or storage system that the tire monitoring controller may access. Determining <NUM>, by the tire monitoring controller <NUM>, one or more measurements <NUM> associated with the tire may be carried out by selecting from a plurality of measurements, the one or more measurements, to use for indirectly determining the load value.

In addition, the method of <FIG> also includes using <NUM>, by the tire monitoring controller <NUM>, the one or more measurements <NUM> to indirectly determine the load value <NUM>. Using <NUM> the one or more measurements <NUM> to indirectly determine a load value <NUM> for the tire may be carried out by applying one or more algorithms or indexes that define a relationship between the one or more measurements and a load value. For example, a general rule is that as the load on the tires is increased, the height of the axel or tires will decrease. An index or algorithm may define this relationship between a particular measurement (e.g., axle height or tire pressure) and the load value. A tire monitoring controller may utilize an index or algorithm that indicates or generates a load value based on the axel/tire height, tire pressure, and the specific of the type of the tire.

For further explanation, <FIG> sets forth a flow chart illustrating an exemplary method of adjustment of indirectly determined values of a tire monitoring controller according to embodiments not falling under the scope of the claims. The method of <FIG> includes identifying <NUM>, by a tire monitoring controller <NUM>, an indirectly determined grip value <NUM> associated with a tire. As explained above, a tire monitoring controller according to embodiments of the present invention may be implemented in a variety of vehicle components. For example, the tire monitoring controller <NUM> may be the example tire monitoring controller <NUM> within the Vehicle Control System <NUM> of <FIG>, the example tire monitoring controller <NUM> within the Telematics Control Unit <NUM> of <FIG>, and the tire monitoring controller <NUM> within the tire sensor <NUM> of <FIG>.

An indirectly determined grip value is an estimate, inference, or other indirectly determined indication of the amount of grip for a tire. Identifying <NUM>, by a tire monitoring controller <NUM>, an indirectly determined grip value <NUM> associated with a tire may be carried out by determining an identification for a particular tire; and selecting, from a plurality of indirectly determined grip values, an indirectly determined grip value having a tag or identification associated with an identification for the particular tire.

In a particular embodiment, the indirectly determined grip value may be generated by another vehicle component other than the tire monitoring controller <NUM>. In this embodiment, a tire monitoring controller may receive one or more indirectly determined grip values from another vehicle component. For example, a tire monitoring controller in a tire sensor may receive indirectly determined grip values generated by a vehicle control system (VCS).

In another embodiment, the indirectly determined grip value may be generated by the tire monitoring controller <NUM>. In this embodiment, the tire monitoring controller may indirectly determine a grip value and store the indirectly determined grip value in a memory or storage location accessible by the tire monitoring controller.

The method of <FIG> also includes identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> from one or more direct measurement devices. A direct measurement device is a device that is configured to directly measure a tire parameter. Tire parameters are values that impact the grip of the tire and therefore may be used to compensate an indirect determination of an initial grip value of the tire. Identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> may also be carried out by requesting and receiving one or more tire parameters from one or more components of the vehicle including a tire sensor, vehicle sensors, a VCS, and a TCU. The tire monitoring controller may have access to memory or a storage location that stores the one or more tire parameters. Alternatively, identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> may be carried out by directly measuring one or more of the tire parameters.

Furthermore, the method of <FIG> includes using <NUM>, by the tire monitoring controller <NUM>, the one or more tire parameters <NUM> to adjust the indirectly determined grip value <NUM>. Using <NUM>, by the tire monitoring controller <NUM>, the one or more tire parameters <NUM> to adjust the indirectly determined grip value <NUM> may be carried out by applying one or more algorithms or indexes that define a relationship between the one or more tire parameters and a grip value. For example, each tire parameter may have a defined relationship with a grip value. An index or algorithm may codify that relationship, such that the tire monitoring controller may adjust a grip value based on the tire parameter.

In a particular embodiment, the grip of a tire may correspond to the load placed on the tire. As a result, the tire parameters (e.g., speed values, tire stiffness parameters, CPL, PRD, load as determined by CPL/PRD) that impact a load value may be used as additional inputs into a tire monitoring controller to adjust an initial grip value.

In a particular embodiment, the one or more tire parameters <NUM> include a tire parameter that is a speed value indicating a measured vehicle speed or rotational speed of the tire. The speed of the tires impacts the centrifugal forces acting on the interior of the tire, which impact deformation of the tire under a load. For example, as a tire rotates across a road surface, the tire is subject to centrifugal force. This centrifugal force acts on the tire in a manner such that the tire is "pulled" in a direction that is outwards from the center of the wheel hub (in the radial plane), having a similar effect as an increase in pressure but with a lesser degree of magnitude. This centrifugal force is proportional to the square of the rotational speed of the tire or the square of the linear velocity of the tire or the vehicle. The tire monitoring controller may use an index or algorithm that defines the relationship between speed values and grip values. In that respect, the additional input of the speed value may be indicated by a measured vehicle speed or tire rotational speed. For example, tire rotational speed may be measured from either the vehicle wheel speed sensors or measured by a tire sensor (e.g., tire mounted sensor (TMS), valve mounted sensor (VMS), or wheel rim sensor). In this example, the wheel speed sensors or tire sensors may communicate the speed value to a vehicle-based system by radio frequency, Bluetooth low energy (BLE), or other means.

In another embodiment, the one or more tire parameters <NUM> include a tire stiffness parameter. As explained above, the magnitude of the expansion due to pressure and speed is dependent on a tire's characteristic stiffness. Differences in tire expansion may impact the deformation of the tire under a load. To determine the stiffness coefficients for a given tire model, various loads and pressures can be applied to the tire using a flat track, a drum tester, a static test, or through a simulation or model. The measurements can then be used to solve for the coefficients of the polynomial function. These coefficients are indicative of the relationship between the vertical compression load at an applied pressure and the resultant tire radial displacement or deformation at the ground contact surface. Additionally, these stiffness coefficients are a gauge of the relationship between the centrifugal radial forces subjected on the tire, which are applicable to pressure and speed, and the degree of resulting circumferential expansion. In a particular embodiment, the tire stiffness coefficients may be expressed as one or more tire stiffness parameters. The tire stiffness parameters may be stored in various locations (e.g., cloud, vehicle ECU, or tire sensor) for access by the tire monitoring controller. The tire monitoring controller may use an index or algorithm that defines the relationship between tire coefficient parameters and grip to adjust the initial grip values.

In another embodiment, the one or more tire parameters <NUM> include a contact patch length (CPL) measurement associated with a length of the tire contact patch with the road surface. As explained above, a CPL measurement may provide an indication of the load on the tires and the grip of the tires is largely dependent on the tire load. As such, using a CPL measurement to adjust an initial grip value may increase the accuracy of the final adjusted grip value.

In another embodiment, the one or more tire parameters <NUM> include a peak radial displacement (PRD) measurement associated with a peak magnitude of radial deformation at the tire contact patch. As with CPL measurements, a PRD measurement may provide an indication of the load on the tires and the grip of the tires is largely dependent on the tire load. As such, using a PRD measurement to adjust an initial grip value may increase the accuracy of the final adjusted grip value.

In another embodiment, the one or more tire parameters <NUM> include a determination of tire load. The determination of tire load may be value that is calculated by some vehicle component (e.g., tire sensor, vehicle sensor, VCS, TCU) using a tire pressure value and a CPL measurement or a PRD measurement. As explained above, the grip of a tire is largely dependent on the tire load. As such, using a load determination based on PRD or CPL to adjust an initial grip value may increase the accuracy of the final adjusted grip value.

In a particular embodiment, the tire monitoring controller may use a plurality of tire parameters (e.g., speed values, tire stiffness parameters, contact path length, peak radial deformation, load as determined by CPL/PRD) to adjust the initial grip value.

For further explanation, <FIG> sets forth a flow chart illustrating an exemplary method of adjustment of indirectly determined values of a tire monitoring system according to embodiments not falling under the scope of the claims. The method of <FIG> is similar to the method of <FIG> in that the method of <FIG> includes all of the elements of <FIG>. However, the method of <FIG> includes additional elements that the tire monitoring controller performs for indirect determination of a grip value. Specifically, the method of <FIG> includes determining <NUM>, by the tire monitoring controller <NUM>, one or more measurements <NUM> associated with the tire.

A measurement <NUM> may be any value useful for inferring, estimating, or otherwise indirectly determining an initial grip value of the tire or evaluating the degree of tire slip. Examples of the one or more measurements <NUM> include but are not limited to an analysis of wheel rotational speed, acceleration, or jerk based on information derived by signals from the vehicle wheel speed sensors. Continuing with this embodiment, the tire monitoring controller may receive the one or more measurements from one or more components of the vehicle including vehicle sensors, vehicle control systems (VCS), Electronic Control Systems (ECS), and Telematics Control Units (TCU). For example, the tire monitoring controller may request and receive the one or more measurements from one or more components of the vehicle. As another example, the tire monitoring controller may be configured to periodically receive the one or more measurements from the one or more components without having to specifically request the one or more measurements. In another example, the one or more components of the vehicle may store the one or more measurements in a memory or storage system that the tire monitoring controller may access. Determining <NUM>, by the tire monitoring controller <NUM>, one or more measurements <NUM> associated with the tire may be carried out by selecting from a plurality of measurements, the one or more measurements, to use for indirectly determining the grip value.

In addition, the method of <FIG> also includes using <NUM>, by the tire monitoring controller <NUM>, the one or more measurements <NUM> to indirectly determine the grip value <NUM>. Using <NUM> the one or more measurements <NUM> to indirectly determine a grip value <NUM> for the tire may be carried out by applying one or more algorithms or indexes that define a relationship between the one or more measurements and a grip value. For example, a general rule is that the amount of wheel rotation speed increases without an increase in vehicle speed, the amount of grip decreases. A tire monitoring controller may utilize an index or algorithm that indicates or generates a grip value for a given type of tire based on the degree of tire slip indicated by the one or more measurements.

For further explanation, <FIG> sets forth a flow chart illustrating an exemplary method of adjustment of indirectly determined values of a tire monitoring system according to embodiments of the present disclosure. The method of <FIG> includes identifying <NUM>, by a tire monitoring controller <NUM>, an indirectly determined wear condition value <NUM> associated with a tire. As explained above, a tire monitoring controller according to embodiments of the present invention may be implemented in a variety of vehicle components. For example, the tire monitoring controller <NUM> may be the example tire monitoring controller <NUM> within the Vehicle Control System <NUM> of <FIG>, the example tire monitoring controller <NUM> within the Telematics Control Unit <NUM> of <FIG>, and the tire monitoring controller <NUM> within the tire sensor <NUM> of <FIG>.

An indirectly determined wear condition value is an estimate, inference, or other indirectly determined indications of use of a tire. Examples of wear condition values include but are not limited to indications of tread depth and tread wear. Identifying <NUM>, by a tire monitoring controller <NUM>, an indirectly determined wear condition value <NUM> associated with a tire may be carried out by determining an identification for a particular tire; and selecting, from a plurality of indirectly determined wear condition values, an indirectly determined wear condition value having a tag or identification associated with an identification for the particular tire.

In a particular embodiment, the indirectly determined wear condition value may be generated by another vehicle component other than the tire monitoring controller <NUM>. In this embodiment, a tire monitoring controller may receive one or more indirectly determined wear condition values from another vehicle component. For example, a tire monitoring controller in a tire sensor may receive indirectly determined wear condition values generated by a vehicle control system (VCS).

In another embodiment, the indirectly determined wear condition value may be generated by the tire monitoring controller <NUM>. In this embodiment, the tire monitoring controller may indirectly determine a wear condition value and store the indirectly determined wear condition value in a memory or storage location accessible by the tire monitoring controller.

The method of <FIG> includes identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> from one or more direct measurement devices. A direct measurement device is a device that is configured to directly measure a tire parameter. Tire parameters are values that impact the wear condition of the tire and therefore may be used to compensate/adjust an indirect determination of an initial wear condition value for the tire. Identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> may be carried out by requesting and receiving one or more tire parameters from one or more components of the vehicle including a tire sensor, vehicle sensors, a VCS, a TCU. The tire monitoring controller may have access to memory or a storage location that stores the one or more tire parameters. Alternatively, identifying <NUM>, by the tire monitoring controller <NUM>, one or more tire parameters <NUM> may be carried out by directly measuring one or more of the tire parameters.

Furthermore, the method of <FIG> includes using <NUM>, by the tire monitoring controller <NUM>, the one or more tire parameters <NUM> to adjust the indirectly determined wear condition value <NUM> for the tire. Using <NUM>, by the tire monitoring controller <NUM>, the one or more tire parameters <NUM> to adjust the indirectly determined wear condition value <NUM> for the tire may be carried out by applying one or more algorithms or indexes that define a relationship between the one or more tire parameters and a wear condition value. For example, each tire parameter may have a defined relationship with a wear condition value. An index or algorithm may codify that relationship, such that the tire monitoring controller may adjust a wear condition value based on the tire parameter.

In a particular embodiment, the wear of a tire may correspond to the load placed on the tire. The general principle being that a higher degree of tire wear is associated with higher load operating conditions. As a result, the tire parameters (e.g., speed values, tire stiffness parameters, CPL, PRD, load as determined by CPL/PRD) that impact a load value may be used as additional inputs into a tire monitoring controller to adjust an initial wear condition value.

In a particular embodiment, the one or more tire parameters <NUM> include a tire parameter that is a speed value indicating a measured vehicle speed or rotational speed of the tire. The speed of the tires impacts the centrifugal forces acting on the interior of the tire, which impact deformation of the tire under a load. For example, as a tire rotates across a road surface, the tire is subject to centrifugal force. This centrifugal force acts on the tire in a manner such that the tire is "pulled" in a direction that is outwards from the center of the wheel hub (in the radial plane), having a similar effect as an increase in pressure but with a lesser degree of magnitude. This centrifugal force is proportional to the square of the rotational speed of the tire or the square of the linear velocity of the tire or the vehicle. The tire monitoring controller may use an index or algorithm that defines the relationship between speed values and wear condition values. In that respect, the additional input of the speed value may be indicated by a measured vehicle speed or tire rotational speed. For example, tire rotational speed may be measured from either the vehicle wheel speed sensors or measured by a tire sensor (e.g., tire mounted sensor (TMS), valve mounted sensor (VMS), or wheel rim sensor). In this example, the wheel speed sensors or tire sensors may communicate the speed value to a vehicle-based system by radio frequency, Bluetooth low energy (BLE), or other means.

In another embodiment, the one or more tire parameters <NUM> include a tire stiffness parameter. As explained above, the magnitude of the expansion due to pressure and speed is dependent on a tire's characteristic stiffness. Differences in tire expansion may impact the deformation of the tire under a load. To determine the stiffness coefficients for a given tire model, various loads and pressures can be applied to the tire using a flat track, a drum tester, a static test, or through a simulation or model. The measurements can then be used to solve for the coefficients of the polynomial function. These coefficients are indicative of the relationship between the vertical compression load at an applied pressure and the resultant tire radial displacement or deformation at the ground contact surface. Additionally, these stiffness coefficients are a gauge of the relationship between the centrifugal radial forces subjected on the tire, which are applicable to pressure and speed, and the degree of resulting circumferential expansion. In a particular embodiment, the tire stiffness coefficients may be expressed as one or more tire stiffness parameters. The tire stiffness parameters may be stored in various locations (e.g., cloud, vehicle ECU, or tire sensor) for access by the tire monitoring system. The tire monitoring system may use an index or algorithm that defines the relationship between tire coefficient parameters and wear to adjust the initial wear condition values.

In another embodiment, the one or more tire parameters <NUM> include a contact patch length (CPL) measurement associated with a length of the tire contact patch with the road surface. As explained above, a CPL measurement may provide an indication of the load on the tires and the wear of the tires is largely dependent on the tire load. As such, using a CPL measurement to adjust an initial wear condition value may increase the accuracy of the final adjusted wear condition value.

In another embodiment, the one or more tire parameters <NUM> include a peak radial displacement (PRD) measurement associated with a peak magnitude of radial deformation at the tire contact patch. As with CPL measurements, a PRD measurement may provide an indication of the load on the tires and the grip of the tires is largely dependent on the tire load. As such, using a PRD measurement to adjust an initial wear condition value may increase the accuracy of the final adjusted wear condition value.

In another embodiment, the one or more tire parameters <NUM> include a determination of tire load. The determination of tire load may be value that is calculated by some vehicle component (e.g., tire sensor, vehicle sensor, VCS, TCU) using a tire pressure value and a CPL measurement or a PRD measurement. As explained above, the wear of a tire is largely dependent on the tire load. As such, using a load determination based on PRD or CPL to adjust an initial wear condition value may increase the accuracy of the final adjusted wear condition value.

In a particular embodiment, the tire monitoring controller may use a plurality of tire parameters (e.g., speed values, tire stiffness parameters, contact path length, peak radial deformation, load as determined by CPL/PRD) to adjust the initial wear condition value.

For further explanation, <FIG> sets forth a flow chart illustrating an exemplary method of adjustment of indirectly determined values of a tire monitoring system according to embodiments of the present disclosure. The method of <FIG> is similar to the method of <FIG> in that the method of <FIG> includes all of the elements of <FIG>. However, the method of <FIG> includes additional elements that the tire monitoring controller performs for indirect determination of a wear condition value. Specifically, the method of <FIG> includes determining <NUM>, by the tire monitoring controller <NUM>, one or more measurements <NUM> associated with the tire.

A measurement <NUM> may be any value useful for inferring, estimating, or otherwise indirectly determining an initial wear condition value of the tire or evaluating the degree of tire slip. Examples of the one or more measurements <NUM> include but are not limited to distance that the tires were driven from last tire change; average speed that the tires are driven; magnitude and frequency of hard braking; average tire pressure; tire pressure measurements; tire temperature; average outside temperature; and other factors or measurements that may occur to those of ordinary skill in the art. Continuing with this embodiment, the tire monitoring controller may receive the one or more measurements from one or more components of the vehicle including vehicle sensors, vehicle control systems (VCS), Electronic Control Systems (ECS), and Telematics Control Units (TCU). For example, the tire monitoring controller may request and receive the one or more measurements from one or more components of the vehicle. As another example, the tire monitoring controller may be configured to periodically receive the one or more measurements from the one or more components without having to specifically request the one or more measurements. In another example, the one or more components of the vehicle may store the one or more measurements in a memory or storage system that the tire monitoring controller may access. Determining <NUM>, by the tire monitoring controller <NUM>, one or more measurements <NUM> associated with the tire may be carried out by selecting from a plurality of measurements, the one or more measurements, to use for indirectly determining the wear condition value.

In addition, the method of <FIG> also includes using <NUM>, by the tire monitoring controller <NUM>, the one or more measurements <NUM> to indirectly determine the wear condition value <NUM>. Using <NUM> the one or more measurements <NUM> to indirectly determine a wear condition value <NUM> for the tire may be carried out by applying one or more algorithms or indexes that define a relationship between the one or more measurements and wear condition value. For example, a general rule is that as the distance that a tire is driven is increased, the amount of wear on the tires is increased and the tread depth of the tires is decreased. A tire monitoring controller may utilize an index or algorithm that indicates or generates a wear condition value based on the specific of the type of tire and the measurement value. In this example, the tire monitoring controller may infer a wear condition value measurement for the tire based on tire parameters, such as a temperature measurement, a tire pressure, and the specifics of the type of the tire.

Exemplary embodiments of the present invention are described largely in the context of a fully functional computer system for adjustment of indirectly determined values of a tire monitoring system. Readers of skill in the art will recognize, however, that the present invention also may be embodied in a computer program product disposed upon computer readable storage media for use with any suitable data processing system. Such computer readable storage media may be any storage medium for machine-readable information, including magnetic media, optical media, or other suitable media. Examples of such media include magnetic disks in hard drives or diskettes, compact disks for optical drives, magnetic tape, and others as will occur to those of skill in the art. Persons skilled in the art will immediately recognize that any computer system having suitable programming means will be capable of executing the steps of the method of the invention as embodied in a computer program product. Persons skilled in the art will recognize also that, although some of the exemplary embodiments described in this specification are oriented to software installed and executing on computer hardware, nevertheless, alternative embodiments implemented as firmware or as hardware are well within the scope of the present invention.

The present invention may be a system, an apparatus, a method, and/or a computer program product.

The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatuses, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatuses or other devices to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, apparatuses, methods, and computer program products according to various embodiments of the present invention.

According to the present invention, there is provided a method for adjustment of indirectly determined values of a tire monitoring system as set out in the independent claims. Embodiments are set out in the dependent claims.

One or more embodiments may be described herein with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope of the claims Further, the boundaries of these functional building blocks have been arbitrarily defined for convenience of description. Alternate boundaries could be defined as long as the certain significant functions are appropriately performed. Similarly, flow diagram blocks may also have been arbitrarily defined herein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence could have been defined otherwise and still perform the certain significant functionality. Such alternate definitions of both functional building blocks and flow diagram blocks and sequences are thus within the scope of the claims. One of average skill in the art will also recognize that the functional building blocks, and other illustrative blocks, modules and components herein, can be implemented as illustrated or by discrete components, application specific integrated circuits, processors executing appropriate software and the like or any combination thereof.

Claim 1:
A method for adjustment of indirectly determined values of a tire monitoring system, the method comprising:
identifying (<NUM>), by a tire monitoring controller (<NUM>), an indirectly determined value (<NUM>) associated with a tire, wherein the indirectly determined value (<NUM>) is a circumferential expansion value indirectly determined from a tire pressure measurement;
identifying by determining (<NUM>), by the tire monitoring controller (<NUM>), one or more tire parameters (<NUM>) from one or more direct measurement devices, wherein the one or more tire parameters (<NUM>) include a tire stiffness parameter;
using (<NUM>), by the tire monitoring controller (<NUM>), the one or more tire parameters (<NUM>) from the one or more direct measurement devices to adjust the indirectly determined value (<NUM>); and
using (<NUM>), by the tire monitoring controller (<NUM>), the adjusted indirectly determined value (<NUM>) to indirectly determine a wear condition value (<NUM>) for the tire.