Patent Description:
In the United States, the Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, is a network of controlled-access highways that forms part of the National Highway System in the United States. Construction of the Interstate Highway System was authorized by the Federal Aid Highway Act of <NUM>. The Interstate Highway System extends throughout the contiguous United States and has routes in Hawaii, Alaska, and Puerto Rico.

With great roads, trucking is an essential component of the economy infrastructure. Indeed, a tractor-trailer vehicle cruising down the Interstate Highway is common. Trucking is involved in the delivery of not only almost every consumer product but industrial products as well. Truck drivers are often independent drivers who may or may not own their own trailer but, in any case, contract to deliver one or more full-load or part-load trailers. Indeed, being a truck driver is one of the most common jobs in America.

A paradigm shift is on the horizon as the asphalt highway is integrated into the information age. Such vehicles will be equipped with a suite of technology to connect to the information superhighway and image the physical superhighway. The vehicles will form a virtual image of the road that is processed for navigation and control. The technology will include cameras, LIDAR, RADAR, sensors of all sorts, motors and of course a large processing capacity (e.g., processors, memory, power supplies etc.).

Problems with transport by tractor-trailer vehicle remain despite the longstanding and ubiquitous use. Mobile vehicles have been slow to beneficially utilize the potential benefits of interconnection and analysis. Other obstacles stem from the typical driver not being comfortable navigating use of sophisticated electronics or various configurations that are simply not interoperable. Further, without drivers, many more tasks and maintenance activities must be automated. Thus, a need exists for easy, automatic connection and operation of vehicles with more sophisticated communication and networking technology on vehicles, particularly tractor-trailer vehicles.

Various types of sensors have been employed on vehicles, and particularly on tractor-trailer trucks. Normally these sensors are placed on the tractor-trailer truck and manually calibrated to trigger a generic alert (e.g. a tire pressure alert) when a certain measurement is returned. This requires the sensors to be initially tested and calibrated on the vehicle. The utility of each sensor is limited to selectively triggering the alert, and no data from the sensors is gathered or processed for analysis.

Further, challenges arise with adequately placing sensors within an existing vehicle system, such as a braking system. It is difficult to place a sensor, or multiple sensors, within an existing braking system without potentially impacting the integrity of the braking system. Further, assemblies for indicating brake wear are typically integrated into consumable components like the pads themselves. Thus, when the pads are changed, the sensor assembly is also replaced.

<CIT> discloses a system for measuring brake pad wear of a vehicle disc brake system. The system includes an inductive sensor and a target. The sensor is mounted on a first component and the target is mounted on a second component. The travel distance can be measured via the brake pads, the pad holders, the floating caliper, or a piston. A sensor controller is provided to calculate brake pad wear in response to the inductance of the coils. The sensor controller can provide results of these calculations to a main controller, such as a vehicle body control module (BCM), which can alert the vehicle operator when necessary.

<CIT> discloses a disc brake monitoring system comprising a sensor assembly configured to detect, during vehicle braking, relative position of a longitudinal member contacting a brake pad carrier, and a processing structure communication with the sensor assembly.

<CIT> discloses a system for measuring brake data from a drum brake assembly: A brake wear is determined by means of a sensor ,e.g. a linear sensor, arranged at the brake caliper. Displacement of the brake caliper is used to determine the brake pad wear. A s-cam can be provided to readjust the position of the brake in the non-actuated state. An angle sensor can be provided which determines the angle position of the s-cam.

The invention relates to a system for measuring brake data from a drum brake assembly of a vehicle, the drum brake assembly including a brake chamber which actuates a push rod when vehicle brakes are applied, actuation of the push rod causing a rotary motion of an adjuster arm and attached slack adjuster head around a cam shaft. The system includes a brake sensor mounted to the drum brake assembly and configured to measure brake data including a displacement of the drum brake assembly during braking. The brake sensor is configured to transmit brake data over a wireless vehicle area.

The drum brake assembly is configured to rotate an s-cam when the brakes are applied such that the s-cam engages two cam followers coupled to opposing brake shoes. In such a case, the displacement of the drum brake assembly measured by the system is representative of a difference in displacement distance between the two cam followers when the brake assembly is in a disengaged state and when the brake assembly is in an engaged state. The system can be further configured to measure an s-cam rotation angle, the difference in displacement distance between the two cam followers being calculated based on the s-cam rotation angle.

In some embodiments, the brake sensor includes a sense element and a target, the sense element configured to sense a magnetic field of the target.

The sense element can be attached to a fixed brake chamber bracket, the fixed brake chamber bracket remaining at a fixed location with respect to the vehicle when the vehicle brakes are applied. In such a case, the target is attached to the pushrod and configured to move, with respect to the sense element, when the vehicle brakes are applied.

In some embodiments, the sense element is attached to a fixed mount plate adjacent the slack adjuster head, the fixed mount plate remaining at a fixed location with respect to the vehicle when the vehicle brakes are applied. In such a case, the target is attached to the slack adjuster head and configured to move, with respect to the sense element, when the vehicle brakes are applied.

In some embodiments, the target is attached to a fixed indicator plate adjacent the cam shaft, the fixed indicator plate remaining at a fixed location with respect to the vehicle when the vehicle brakes are applied. In such a case, the sense element is attached to the adjuster arm such that the sense element moves as the adjuster arm and cam shaft rotate when the vehicle brakes are applied.

In some embodiments, the braking system further comprises at least one temperature sensor. In such a case, the wireless hub can be further configured to detect an anomaly in a temperature measured by the at least one temperature sensor during a time period. After detecting an anomaly, the wireless hub can compare the temperature measured by the at least one temperature sensor during the time period to temperature data from at least one wheel end temperature sensor. The wireless hub can then generate and transmit an alert when the comparison is indicative of a fault condition.

In some embodiments, the system is configured to determine a current brake pad thickness by calibrating the drum brake assembly at an initial brake pad thickness (ti) and initial s-cam rotation angle (θi). The system determines a slope of a plot of cam follower displacement over s-cam rotation angle (m). The system measures a current s-cam rotation angle (θn). Finally, the system calculates the current brake pad thickness by setting the current brake pad thickness as equal to the following: ti - m (θn - θi). In some cases, the system is configured to provide an alert based on an expected brake pad failure thickness. In some cases, the system is configured to provide an indicator of one or more of the following: a distance until drum brake assembly maintenance is recommended; or a distance until drum brake assembly failure is expected. Actual data about particular driver habits and/or expected routes may also be used in the maintenance calculation.

In some embodiments, the target portion is a magnet that generates a magnetic field and the sensing element is an anisotropic magnet resistivity sensor configured to sense the magnetic field of the magnet to generate a signal.

So that those having ordinary skill in the art to which the disclosed system pertains will more readily understand how to make and use the same, reference may be had to the following drawings.

The subject technology overcomes many of the prior art problems associated with vehicle sensor systems for connecting sensors to vehicle brakes and processing sensor data. The advantages, and other features of the systems and methods disclosed herein, will become more readily apparent to those having ordinary skill in the art from the following detailed description of certain preferred embodiments taken in conjunction with the drawings which set forth representative embodiments of the present invention. Like reference numerals are used herein to denote like parts. Further, words denoting orientation such as "upper", "lower", "distal", and "proximate" are merely used to help describe the location of components with respect to one another. For example, an "upper" surface of a part is merely meant to describe a surface that is separate from the "lower" surface of that same part. No words denoting orientation are used to describe an absolute orientation (i.e. where an "upper" part must always be at a higher elevation).

Referring now to <FIG>, an exemplary vehicle <NUM> is shown utilizing a vehicle area network (VAN) <NUM> in accordance with the subject technology. The vehicle <NUM> has a tractor <NUM> for pulling two trailers 104a, 104b. The tractor <NUM> may haul just a single trailer or multiple trailers, and as many as five. It is typically the responsibility of the truck driver to not only ensure the safe and proper operation of the vehicle <NUM> but to also connect and disconnect the trailers 104a, 104b. The tractor <NUM> also includes a cabin <NUM> having a dashboard (not explicitly shown) for presenting information related to the trailers 104a, 104b. The tractor <NUM> has front wheels 105a, which can be steered to control direction of the tractor <NUM>. The tractor <NUM> also has rear wheels 105b. A dolly <NUM> facilitates mechanical connection of the first and second trailers 104a, 104b. The trailers 104a, 104b and dolly <NUM> also include wheels <NUM>.

The trailers 104a, 104b and dolly <NUM> are equipped with a plurality of sensors for monitoring position, speed, temperature, pressure, weight and the like for various purposes. In <FIG>, the components of the VAN <NUM> such as sensors 110a-c are shown schematically to illustrate possible locations and configurations. The driver is provided with a pairing device <NUM> for making wireless connections between the VAN <NUM> and the sensors <NUM>. The pairing device <NUM> also can monitor the status of the trailers 104a, 104b as well as connect to the devices of the VAN <NUM>. The pairing device <NUM> may be a tablet, smart phone, or specialized controller and the like.

The VAN <NUM> establishes communication between numerous components of the vehicle <NUM>. Individual components can be connected wirelessly, wired and combinations thereof. The connections may utilize various communication protocols, as will be discussed in more detail herein. The VAN <NUM> can utilize WiFi to establish a high bandwidth backbone, in effect a first level of the VAN <NUM>. The VAN <NUM> may include any number of sub-networks, in effect second levels of the VAN <NUM>. For example as shown in <FIG>, the VAN <NUM> includes a tractor subnetwork <NUM> and a trailer subnetwork <NUM>. Each subnetwork <NUM>, <NUM> includes one or more wireless hubs 130a-d. The first trailer 104a includes the wireless hub 130b, the dolly <NUM> includes the wireless hub 130c and the second trailer 104b includes wireless hub 130d. As the tractor <NUM>, trailers 104a, <NUM> and dolly <NUM> are often reconfigured with other trailers and dollies, quick and easy pairing to establish the subsequent vehicle area network is beneficial.

The VAN <NUM> also includes a first telematics module 116a on the tractor <NUM> and in communication the tractor hub 130a as well as a second telematics module 116b on the first trailer <NUM> and in communication with the first trailer hub 130b. The telematics modules 116a, 116b also communicate with external networks <NUM> having external devices <NUM>. The telematics modules 116a, 116b communicate with the external networks <NUM> via cell towers <NUM>. Preferably, the tractor <NUM> has a chassis CAN bus <NUM> over which the tractor hub 130a and the telematics module 116a communicate. The trailers 104a, 104b may be substantially identical or quite differently configured not just in terms of hardware but software. However, the VAN <NUM> can automatically integrate components so that the driver is needed for little pairing activity with the smart device <NUM> if any at all. Telematics modules and services are available commercially from numerous suppliers, such as CalAmp of Irvine, California.

The wireless hubs 130a-d are powered by a wired power line communication (PLC) cable, typically connected by the driver when mechanically coupling the trailer 104a, 104b to the tractor <NUM>. The wireless hubs 130a-d communicate using WiFi with a <NUM>. <NUM> thread network protocol and/or over the CAN bus <NUM>. The wireless hubs 130a-d can also communicate by common lower power friendly means such as Bluetooth or <NUM> technology. The wireless hubs 130a-d can also use near-field communication as well as with any other wireless communication protocol now known or later developed.

The hubs 130a-d can be connected to one or more components or each other using a wired connection. For example, the tractor hub 130a can be connected to the front trailer hub 130b with a wired cable connection. The wired cable connection can optionally provide power from the tractor hub 130a to the trailer hub 130b while simultaneously allowing communication through PLC techniques. The wired connection can allow the tractor hub 130a and the first trailer hub 130b to automatically pair upon making the physical connection. During pairing, the hubs 130a, 130b communicatively connect utilizing the PLC connection to share credentials of the VAN <NUM> in accordance with out of band pairing techniques. Similarly, the hubs 130c, 13d can also be hard wired and automatically integrated into the VAN <NUM>.

Each wireless hub 130a-d acts as central communication or access point for devices within the respective local area or subnetwork <NUM>, <NUM> of the vehicle <NUM>. To that end, the tractor wireless hub 130a creates the tractor subnetwork <NUM> for all devices in and around the tractor <NUM> of the vehicle <NUM>. Similarly, the first trailer hub 130b creates the trailer subnetwork <NUM> for all devices in and around the first trailer 104a. Further, a wireless hub 130c on the dolly <NUM> is part of the first trailer subnetwork <NUM> but could even form another subnetwork. Other subnetworks may also be included, for example, for other additional trailers, dollies, and/or areas of the truck.

Still referring to <FIG>, the tractor wireless hub 130a establishes communication to the tractor telematics module 116a, the pairing device <NUM> and the first trailer wireless hub 130b to establish the tractor subnetwork <NUM>. The tractor hub 130a can communicate with the first trailer hub 130b by PLC and/or WiFi, with the pairing device <NUM> by WiFi, and over the CAN bus <NUM> with the telematics module 116a. In one embodiment, the tractor hub 130a uses Thread networking communication technology based on the IEEE <NUM>. <NUM> radio standard for low power consumption and latency. The communication protocol may include AES <NUM> encryption with a media access control (MAC) layer network key.

The tractor <NUM> also includes a plurality of sensors 110a. For simplicity in <FIG>, only one sensor 110a is shown schematically, but represents any kind of sensor in any location. In order to facilitate communication between the tractor hub 130a and the sensor 110a, the tractor subnetwork <NUM> can include a range extender transmitter/receiver 170a paired with the sensor 110a. Depending upon the sensor configuration, the sensor 110a may also communicate directly with the tractor hub 130a. The transmitter/receiver 170a and sensor 110a may utilize Thread networking communication technology among others.

For example, communication between the transmitter/receiver 170a and sensor 110a may be via Bluetooth communication. The transmitter/receiver 170a acts as a range extender for the sensor 110a. However, Bluetooth is susceptible to eavesdropping so that out of band (OOB) pairing is needed. The pairing device <NUM> is used to accomplish the OOB pairing. The pairing device <NUM> can use near-field communication (NFC) with the hubs 130a-d, sensors 110a-d and transmitter/receivers 170a-d.

Pairing the components 110a-d, 130a-d, 170a-d can use multiple technologies and techniques in any combination. The example given here is based on the normal commissioning/ pairing process for a Thread device. The pairing device <NUM> can use WiFi or even read a barcode to link to the hub 130a. Once linked to the hub 130a, the pairing device <NUM> can use RFID technology such as an NFC tag to establish the OOB (Out of Band) pairing connection to the transmitter/receiver 170a and sensor 110a. NFC technology is desirable because the pairing device <NUM> could simply be a smart phone running an application and held in proximity to the transmitter/receiver 170a or sensor 110a. The OOB pairing link can use datagram transport layer security (DTLS), which is a communications protocol that provides security by allowing communication in a way that is designed to prevent eavesdropping, tampering, and message forgery. Additionally, access can be protected by using a pre-shared key (PSK) generated by an algorithm such a J-PAKE.

Once the pairing device <NUM> establishes communication between the hub 130a, sensor 110a and transmitter/receiver 170a, the tractor subnetwork <NUM> is established. In a similar manner, the trailer subnetwork <NUM> can be established. The first trailer hub 130b establishes the first trailer subnet <NUM> that also includes a plurality of sensors 110b. Again for simplicity, only a single sensor 110b is shown schematically representing, for example, a TPMS. A transmitter/receiver 170b is paired with the sensor 110b. The first trailer 104a also includes a telematics module 116b and beacon <NUM>, both of which are part of the first trailer subnetwork <NUM>. The telematics module 116b communicates with external networks <NUM> via a cell tower <NUM> as well. The beacon <NUM> may also communicate directly, whether wired or wirelessly, with the tractor hub 130a.

The tractor hub 130a is also paired to the trailer hub 130b so that the respective subnetworks <NUM>, <NUM> are in secure communication. To pair the hubs 130a, 130b, the OOB pairing link can use a physical connection with ISO <NUM>, which is a CAN based vehicle bus standard in the heavy-duty truck industry for communication between the tractor and one or more trailers. The pairing of the hubs 130a, 130b can share a unique data key such as a key generated by AES-<NUM> encryption.

The beacon <NUM> provides a separate means of transmitting information wirelessly. In particular, the beacon <NUM> can be configured to act as a GPS, transmitting location data for the first trailer, allowing a remote user to locate the trailer. The beacon <NUM> is particularly useful for tractor drivers who are picking up a trailer from a large lot of many trailers. For example, certain lots tend to store an enormous number of trailers and are not well organized or marked, requiring drivers to search to locate a particular trailer. Typically, the driver is tasked with seeking out the trailer through a particular identifier on the trailer, such as a license plate. This inefficiently requires the driver to look individually at the license plate of each trailer on the lot to determine whether it is the correct trailer. Further, license plates can be difficult to read accurately from a distance, requiring the driver to approach each license plate within a reasonable distance or even get out of the tractor. As such, the beacon <NUM> improves the manual searching process by providing a GPS signal to the external networks <NUM> which ultimately is received by telematics module 116a in the tractor <NUM>. Thus, the beacon GPS signal can be used by the driver to quickly and easily locate the trailer 104a within the lot. It is envisioned that the dashboard of the tractor <NUM> may display not only the location of the beacon <NUM> but assist with directions on how to drive to the beacon <NUM>. The beacon <NUM> can also include a clear visual identifier, such as a blinking light of a specified color or a display showing an identifier, to alert the driver when the driver is close to the correct trailer 104a. The beacon <NUM> eliminates the need for the driver to carefully search the entire lot and allows the driver to quickly and easily identify and connect to the proper trailer.

Still referring to <FIG>, the dolly <NUM> and second trailer 104b also include respective hubs 130c, 130d that become part of the VAN <NUM>. The hubs 130c, 130d similarly communicate with a plurality of sensors 110c, 110d and any transmitter/receiver 170c, 170d paired with the sensors 110c, 110d. Depending upon the configuration, the hubs 130c, 130d may form subnetworks or simply communicate with the first trailer hub 130b, which relays the information to the tractor hub 130a. The second trailer 104b can include a telematics module, beacon and other hardware as needed.

Generally, a transmitter/receiver 170a-d is positioned proximate a respective sensor, which may be pressure, temperature, speed, position, or other sensors. The transmitter/receiver 170a-d receives measured data from one or more sensors and reports that data to the local hub wirelessly. The transmitter/receiver170a-d may also use the <NUM> frequency band for communication. In other cases, the sensors 110a-d are wired directly to the local hub 130a-d, or are connected wirelessly directly to the local hub 130a-d.

It is envisioned that the subnetworks <NUM>, <NUM> can be established in advance. In other words, for the trailer subnetwork, pairing the sensor 110b, transmitter/receiver 170b and hub 130b can be accomplished during assembly by a technician using a pairing device <NUM>. As noted above, the pairing may be very automatic, and to the extent needed, performed by the driver upon connection of the trailer 104a. Many sensors and such devices can be difficult to physically access so that pairing upon installation is advantageous. A sensor, for example, might be located on an axle of the vehicle or within a vehicle braking system. The driver or technician's pairing device <NUM> may be able to read a code from the sensor, such as a QR code or NFC tag. The technician's pairing device <NUM> will be trusted by the VAN <NUM> (e.g. having passcode credentials for the network, or the like) and/or can be manually connected to the VAN <NUM>, whether wired or wirelessly. The pairing device <NUM> can then pair the sensor 110b to the hub 130b using the code from the sensor 110b, thereby connecting the sensor 110b to the subnetwork <NUM> and, ultimately, to the VAN <NUM>.

Once the transmitter/receivers 170a-d are paired for wireless communication to corresponding wireless hubs 130a-d, information can then be transmitted from multiple devices across the VAN <NUM>. The data can be processed and provided to a central location of the vehicle <NUM>, such as within the tractor <NUM> where the driver can see alerts, or other feedback related to the readings of the sensors 110a-d.

In some cases, one or more of the tractor <NUM> and trailers 104a, 104b can include a 3rd party, on-board telematics device 116a, 116b. In the example shown, the tractor hub 130a is in communication with a first telematics device 116a and the first trailer hub 130b is in communication with a second telematics device 116b in the first trailer 104a. Each telematics device 116a, 116b transmits data to a third party source. In the example given, the data is transmitted to an external cloud platform where the data can then be obtained by external devices <NUM>, such as computers, smartphones or the like (e.g., the pairing device <NUM>). The data can then be relied upon for fleet and asset management functions, such as checking health of various components of the truck. In other cases, the telematics devices 116a, 116b can transmit to mediums other than a cloud network, such as a wide area network or directly to third party devices.

Once information from the VAN <NUM> is transmitted out of the vehicle <NUM> to the external networks <NUM> and devices <NUM>, additional data review, analysis and insight can be ascertained. The analysis and insight can then be sent back to the trailer <NUM> for review by the driver. A suite of warning strategy functionality can be general or specific to particular needs. The algorithm that develops the warnings is optimized by ongoing data analysis. For example, the vehicle behavior is characterized so that particularly identified parameters can be measured. Some parameters are tire pressure with reference temperature, spare tire pressure, system temperature, system pressure, and gross vehicle weight (GVW). The external device <NUM> may have specific data such as a range or maximum allowable limit. Since the maintenance of these parameters is ongoing, if the GVW is over limit or out of range, or a tire is under low pressure or unsafe to drive on, a warning message can be sent to the driver for investigation and corrective action. For another example, a fast pressure loss in a tire would generate an alert to the driver.

The subnetworks <NUM>, <NUM> for the vehicle <NUM> are part of and in local communication within the broader VAN <NUM>, with one wireless gateway hub acting as an access point for the VAN <NUM>. In some cases, the access point for the VAN <NUM> can change to a different gateway depending on the number of trailers <NUM> attached to the tractor <NUM> such that the access point is in a central location of the vehicle <NUM>. To centralize the access point, the tractor hub 130a searches down the length of the vehicle <NUM> for additional hubs <NUM> to determine a centrally located hub <NUM>. Since the hubs <NUM> will be somewhere along the length of the vehicle <NUM>, the VAN <NUM> can determine hub locations through a linear search, rather than by searching a broad surrounding radius.

If, for example, only a single trailer 104a is provided, the access point can be the wireless hub <NUM> in the center of the one trailer, which all devices (e.g., transmitter/receivers, sensors and the like) in the trailer 104a or tractor <NUM> can wirelessly reach. If the second trailer 104b is included, the access point could still be located within the first trailer 104a at a location central to the vehicle <NUM> or, alternatively at the dolly hub 130c which is also centrally located. If additional trailers are added (e.g. a third and fourth trailer), the access point can be changed to a new hub at a central location of the vehicle <NUM>, or can use multiple interconnect access points to leap frog wireless signals through the entire length of the vehicle <NUM>. Alternatively, a full WiFi mesh system could be used to connect many hubs at locations across the vehicle <NUM>. Having wireless hubs 130a-d which control the central communication at each area of vehicle <NUM> allows many devices to quickly and easily communicate over the VAN <NUM>, even when devices within the VAN <NUM> may be changed (e.g., sensor repair), or new or additional trailers and dollies may be added to the vehicle <NUM>. In each case, each new device need only be paired and connected to one wireless hub, and data from all devices can be shared across the VAN <NUM>. From the above, it should be understood that the exact number and arrangement of the components shown in <FIG> are exemplary only, and should not be construed as limiting.

As vehicles become self-driving, the subject technology wills seamlessly integrate with the suite of autonomous technology. For example, the data analysis from monitoring the sensors can be used to control speed or even redirect the autonomous vehicle to a service station or rest stop to attend to repairs. The data analysis may also require the autonomous vehicle to enter an emergency mode where the vehicle may be pulled over for towing or control ceded to a remote operator.

In one embodiment, the tractor and the trailer are merged as one. As would be expected, the integration of sensors on the trailer portion into the vehicle area network on the merged tractor-trailer is only required initially. The merged tractor-trailer can still connect and carry additional trailers.

As used herein, a micro controller, computer or smart device is one or more digital data processing devices. Such a device generally can be a personal computer, computer workstation (e.g., Sun, HP), laptop computer, a tablet computer, server computer, mainframe computer, handheld device (e.g., personal digital assistant, Pocket PC, cellular telephone, etc.), information appliance, printed circuit board with components or any other type of generic or special-purpose, processor-controlled device, with or without application specific integrated circuits (ASICs), capable of receiving, processing, displaying, and/or transmitting digital data. A controller includes random access memory (RAM), mechanisms and structures for performing input/output operations, a storage medium such as a magnetic hard disk drive(s), and an operating system (e.g., software) for execution on a central processing unit (CPU). The controller also has input and output devices such as a display screen, a keyboard and mouse and the like.

A CPU generally is logic circuitry that responds to and processes instructions that drive a controller and can include, without limitation, a central processing unit, an arithmetic logic unit, an application specific integrated circuit, a task engine, and/or any combinations, arrangements, or multiples thereof. Software or code generally refers to computer instructions which, when executed on one or more digital data processing devices, cause interactions with operating parameters, sequence data/parameters, database entries, network connection parameters/data, variables, constants, software libraries, and/or any other elements needed for the proper execution of the instructions, within an execution environment in memory of the digital data processing device(s).

A module is a functional aspect, which may include software and/or hardware. Typically, a module encompasses the necessary components to accomplish a task. It is envisioned that the same hardware could implement a plurality of modules and portions of such hardware being available as needed to accomplish the task. Those of ordinary skill will recognize that the software and various processes discussed herein are merely exemplary of the functionality performed by the disclosed technology and thus such processes and/or their equivalents may be implemented in commercial embodiments in various combinations without materially affecting the operation of the disclosed technology.

Referring now to <FIG>, an exploded view of a wireless hub <NUM> is shown. Each hub 130a-d may be differently configured, but in <FIG> an exemplary hub <NUM> is shown. The wireless hub <NUM> includes an enclosure <NUM> with a removable lid <NUM> that connects to form a protected interior <NUM>. The enclosure <NUM> forms opposing recesses <NUM> for compression limiters <NUM> to maintain the joint integrity of the plastic enclosure <NUM>. The hub <NUM> includes a printed circuit board (PCB) <NUM> having electronics, such as a processor and memory (not explicitly shown) required to create modules to carry out the functions of the wireless hub <NUM>, including data processing, storage, and transmission.

The wireless hub <NUM> has an antenna (not shown explicitly) connected to the PCB <NUM> for wireless transmission. Additional antennas may be included as needed to allow the hub <NUM> to transmit and receive data with other devices as described herein. For wired connections, the hub <NUM> includes connecting pins <NUM>. The hub <NUM> may be powered by a battery and/or from a wired connection. In one embodiment, the hub <NUM> is connected to a + <NUM>/24V supply <NUM> (see <FIG>). The wireless hub <NUM> is configured to withstand large temperature changes in the range of -<NUM> to +<NUM>. The hub <NUM> mounts external to the tractor cabin such as on the chassis rail.

Referring now to <FIG>, a schematic diagram of a micro controller <NUM> suitable for use as a portion of the wireless hub <NUM> is shown. Typically, the micro controller <NUM> is part of the PCB <NUM> of <FIG>. The PCB <NUM> includes additional separate peripheral modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and such may be incorporated into the micro controller <NUM>. The micro controller <NUM> and modules <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may include one or more standardly available components or be fabricated as one or more ASICs.

The hubs 130a-d can transmit and/or receive data between other hubs and/or range extenders 170a-d using a WiFi module <NUM> with a <NUM> frequency band. The WiFi module <NUM> creates tractor-to-trailer transparent IP-based data communication. A second <NUM>. <NUM> thread network protocol communication module <NUM> can send and receive additional sensor content and range extension. A third communication module <NUM> can use sub-GHz (e.g., a <NUM> frequency band) with on-board decode and polling functionality for low power modes. The third communication module <NUM> is particularly well-suited for data from nearby sensors that are battery powered and, thus, low power.

The micro controller <NUM> can also be connected for communication to a CAN bus <NUM>, which is typically located in the tractor <NUM>. The micro controller <NUM> can also be directly connected to another wireless hub <NUM> so that the hub <NUM> can act as a radio frequency (RF) to CAN gateway. The PCB <NUM> also includes a <NUM>/<NUM> V power supply <NUM> with surge protection to power and protect the micro controller <NUM> and other components from electrical damage.

When the micro controller <NUM> is operating, hardware <NUM> creates a runtime environment (RTE) <NUM> so that the stored programs are running (e.g., instructions are being executed). The hardware <NUM> includes a processor <NUM> coupled to memory <NUM> along with other components not explicitly shown. Programs are stored in the memory <NUM> and accessed by the processor <NUM>. A boot loader module <NUM> allows programming to the memory <NUM>. An operating system module <NUM> allows the user to interface with the hardware <NUM>. An ECU abstraction layer module <NUM> facilitates uniform access to the micro controller functions performed by peripherals and application program interfaces (APIs). A MCAL micro controller abstraction layer module <NUM> facilitates direct access to the devices on the PCB <NUM>. A complex device drive module <NUM> includes various sub-modules 155a-c to implement drivers for the communication devices <NUM>, <NUM>, <NUM> as needed. The boot-loader module <NUM> can run the micro controller <NUM> for programming and writing information to the memory <NUM>.

As can be seen, the micro controller <NUM> is specifically designed for use in the VAN <NUM>. The micro controller <NUM> also includes a power manager module <NUM> and a Truck to Trailer network link software module <NUM>. The micro controller <NUM> includes a TPMS module <NUM> and onboard weight motor vehicle unit module <NUM> to accomplish TPMS and MVU weight measurements in the VAN <NUM>. The micro controller <NUM> also includes a RF network management module <NUM> and a third party software component module <NUM> to facilitate use of RF network components and third party software. Other modules may be present in the micro controller <NUM> to accomplish any desired features in the VAN <NUM>. Further, the micro controller <NUM> features may be expanded by having hardware and software ready to host additional software and support other components (e.g., additional sensors, hubs, subnetworks).

Referring now to <FIG> and <FIG>, an exploded view and a schematic view of an exemplary transceiver/receiver <NUM> are shown, respectively. The transmitter/receiver <NUM> includes an enclosure <NUM> forming a cavity <NUM> that is sealed with a lid <NUM> for protection of a printed circuit board (PCB) <NUM>. Again, one or more compression limiters <NUM> fit in the enclosure <NUM> to maintain the joint integrity of the plastic enclosure <NUM>. The PCB <NUM> includes the electronics to carry out all the functions of the transmitter/receiver <NUM> including sending/receiving data, data processing, and storage. The PCB <NUM> may include a processor, memory, an antenna and other components (not explicitly shown).

For wired connections, the transmitter/receiver <NUM> includes a connector <NUM>. The transmitter/receiver <NUM> may be powered by a battery and/or from a wired connection. In one embodiment, the hub <NUM> is connected to a + <NUM>/24V supply <NUM>. The transmitter/receiver <NUM> is also configured to withstand large temperature changes in the range of -<NUM> to +<NUM>. Preferably, the transmitter/receiver <NUM> can mount in any suitable location but outside the chassis rail is preferred.

Typically, most, if not all functional modules, are created by components of the PCB <NUM> but one or more peripheral components <NUM>, <NUM>, <NUM> could also be utilized. The PCB <NUM> may include one or more standardly available components or be fabricated as one or more application specific integrated circuits (ASICs). The components of the PCB <NUM> work together to form a central processing unit <NUM>.

The transmitter/receiver <NUM> can transmit and/or receive data to hubs and/or other transmitter/receiver <NUM> using a <NUM>. <NUM> thread network protocol communication module <NUM> as well as send and receive additional sensor content. Thus, the transmitter/receiver <NUM> can be used to enlarge the size of the VAN <NUM>. A sensor communication module <NUM> uses sub-GHz (e.g., a <NUM> frequency band) for low power modes to efficiently work with nearby sensors that are battery powered.

When the transmitter/receiver <NUM> is operating, a runtime environment (RTE) <NUM> is created so that the stored programs are running (e.g., instructions are being executed). The PCB <NUM> may include a processor coupled to memory along with other components not explicitly shown. The programs are stored in the memory and accessed by the processor. One program is an operating system module <NUM> that allows the user to interface with the hardware <NUM>, typically using the pairing device <NUM>.

A hardware abstraction layer module <NUM> facilitates uniform access to the range extender functions. A supplier software development kit (SDK) module <NUM> facilitates creation of applications with advanced features specific to the transmitter/receiver <NUM> and operating system module <NUM>. The PCB <NUM> includes a communications stack module <NUM> to support the <NUM>. <NUM> thread network protocol communication module <NUM>.

As can be seen, the transmitter/receiver <NUM> is specifically designed for use in the VAN <NUM>. The transmitter/receiver <NUM> includes a power manager module <NUM> and a packet forwarder module <NUM> for assisting with data conversion. The transmitter/receiver <NUM> also includes a diagnostic and commissioning module <NUM> that provides a user interface via the smart device <NUM> for start-up and troubleshooting purposes. Other modules may be present in the transmitter/receiver <NUM> to accomplish any desired features in the VAN <NUM>. Further, the transmitter/receiver <NUM> features may be expanded by having hardware and software ready to host additional software and support other components.

The transmitter/receiver <NUM> is particularly beneficial when retrofitting technology on to an existing trailer or tractor for future incorporation into a vehicle area network. The transmitter/receiver <NUM> may connect to various sensors, wired or wirelessly, then pass along the data to a wireless hub. In effect, the transmitter/receiver <NUM> is the additional hardware to bridge communications with existing hardware to the new networked components.

Further, the sensors may also be retrofit. For example, see <CIT> entitled TIRE PRESSURE MONITOR WITH VARIABLE ANGLE MOUNTING, which is incorporated herein by reference. In addition to sensors indicating the tire pressure, the sensors may auto-locate or be programmed to indicate wheel position. As such, when the VAN <NUM> identifies a pressure reading, the pressure reading is associated with a specific tire. The tire-related data can include temperature data as well, which is also an indication of proper and improper performance.

It is envisioned that the smart device <NUM> can be used to assist in refilling tire pressure alleviating the need for a tire pressure gauge by having the pressure reading on the smart device <NUM> or other indicia, such as beeping the horn/flashing the lights, to indicate that the pressure is within specification. If the tire is equipped with automatic tire fill, the VAN <NUM> can trigger refill and stop at the desired pressure. The sensors can also provide an indication that the lift axle is lowered but the tire is not turning. In this instance, a tire lock warning could be generated and/or acted upon such as in an autonomous vehicle. Similarly, a tire blow out can be detected quickly after the burst event to send a warning indicating the blow out and location. In the self-driving vehicle, the tire burst warning generates a reaction for safety and control. Preferably, the sensors are battery powered with efficient power usage for long life.

Referring now to <FIG> and <FIG>, a perspective and a bottom exploded view of a beacon <NUM> in accordance with the subject technology is shown. The beacon <NUM> may mount to the trailer 104a magnetically, with a bracket or by any other fastener. A bottom plate <NUM> forms two recesses <NUM>. Screws <NUM> hold magnets <NUM> in the recesses <NUM> so that the beacon <NUM> can simply be placed against the trailer 104a for mounting and easily removed without tools for wireless charging, relocation, repair and the like. The bottom plate <NUM> has an indicia arrow <NUM>.

The beacon <NUM> also includes a rechargeable battery <NUM> for a power source. A printed circuit board (PCB) <NUM> has an LED <NUM> (shown in dashed lines) that illuminates to show such information as the status of the trailer 104a (e.g., connected to the VAN <NUM> (e.g., solid light) or in process of being connected (e.g., flashing light)). The PCB <NUM> also has components to wirelessly communicate with the hubs 130a-d and or transmitter/receivers 170a-d. The PCB <NUM> is also equipped to interface with a smart device <NUM> that can use near-field communication (NCF). The PCB <NUM> also has a GPS module <NUM> (shown in dashed lines) so that the VAN <NUM> can locate the beacon <NUM>, and in turn the trailer 104a at a great distance as described above. The beacon <NUM> also has a PCB top plate <NUM> for protecting the PCB <NUM>. The PCB top plate <NUM> has a translucent window <NUM> aligned with the LED <NUM>. A top cover <NUM> couples to the bottom plate <NUM> to seal the battery <NUM>, PCB <NUM> and PCB top plate <NUM> within an oval housing <NUM>. Preferably, the top cover <NUM>, bottom plate <NUM>, PCB <NUM>, PCB top plate <NUM> and oval housing <NUM> have features <NUM> for screwing together. The PCB top plate <NUM> and top cover <NUM> also have a plurality of aligned holes <NUM>.

Referring now to <FIG>, another exemplary vehicle area network (VAN) <NUM> for a tractor-trailer vehicle <NUM> is shown. The components and functionality of the VAN <NUM> and tractor-trailer vehicle <NUM> can be similar to the vehicle <NUM> and VAN <NUM> described above, except as otherwise indicated herein. Thus, like reference numerals in the "<NUM>" series represent similar components. For clarity, several components are not shown.

The vehicle <NUM> includes a tractor <NUM> with three trailers 304a-c and two dollies <NUM>, all including components similar to those discussed with respect to <FIG>. The VAN <NUM> allows for communication between all of the components of the vehicle <NUM>, such as wireless hubs 330a-d, sensors 310a-f(e.g., TPMS, pressure sensors, temperature sensors and the like), beacons <NUM>, and the like, as discussed above. The tractor <NUM> and each trailer 304a-c have a corresponding subnetwork 314a-c within the VAN <NUM> which connects the components proximate the respective trailer 304a-c. Although not shown, it is envisioned that the VAN <NUM> includes transmitter/receivers and other components as desirable for robust performance. Each trailer 304a-c also includes a beacon <NUM> for assisting the driver in assembling the vehicle <NUM>.

It is advantageous for the VAN <NUM> to be informed of the relative location of the trailers 304a-c and/or subnets 314a-c established on the vehicle <NUM>. The VAN <NUM> having the relative location helps to identify where various sensors, and other components such as the tires, are located. In some cases, it can be a challenge for the VAN <NUM> to identify the exact ordering of the trailers 304a-c. Further, even if this is manually calibrated, trailers are often dropped off, and new trailers picked up and attached to the truck, requiring the new trailers to be ordered within the VAN <NUM>. Therefore, it is advantageous for the VAN <NUM> to be capable of connecting to and establishing communication with trailers automatically and determining an order of the trailers.

Referring now to <FIG>, a flowchart <NUM> of a method for automatically recognizing the order of three trailers 304a-c on the vehicle <NUM> is shown. The method relies on data, including signal strength and time of flight (ToF) to continuously monitor and update the status of the vehicle <NUM>. The flowchart herein illustrates the structure or the logic of the present technology, possibly as embodied in computer program software for execution on by the hardware described herein. Those skilled in the art will appreciate that the flowchart illustrates the structures of the computer program code elements, including logic circuits on printed circuit boards having integrated circuits that function according to the present technology. As such, the present technology may be practiced by a machine component that renders the program code elements in a form that instructs a digital processing apparatus (e.g., micro controller or computer) to perform a sequence of function step(s) corresponding to those shown in the flowchart.

At step <NUM>, the method starts with the micro controller of each hub 330a-d being powered up and in normal operation to form the respective subnetworks <NUM>, 314a-c but, at this time, the trailer order is unknown and the trailers 304a-c can be in any order. At step <NUM>, each subnetwork <NUM>, 314a-c monitors received signal strength indicators (RSSI) and ToF data from all other subnetworks <NUM>, 314a-c. If other hubs were not present, the same data could come from range extenders or even directly from sensors.

At steps <NUM> and <NUM>, the tractor hub 330a identifies a trailer subnetwork 314a with the highest RSSI and the shortest ToF. The trailer subnetwork 314a with the highest RSSI and shortest ToF should be the lead trailer 304a physically closest to the tractor <NUM>. At step <NUM>, the tractor hub 330a compares the subnetwork 314a identified with the highest RSSI to the subnetwork 314a with the shortest ToF. If the subnetworks of steps <NUM> and <NUM> do not match, meaning the subnetwork with the highest RSSI is different from the subnetwork with the shortest ToF, the method restarts at step <NUM>. At step <NUM>, if there is a match by both being subnetwork 314a, subnetwork 314a is identified as being on the first trailer 314a (e.g., the lead trailer). Further, if at step <NUM>, there is only an RSSI and ToF from the same subnetwork 314a, then the tractor subnetwork <NUM> can identify the associated trailer 304a as the one and only trailer present.

After the lead trailer 304a is identified successfully, the lead trailer wireless hub 330b identifies the subnetwork 314b with the highest RSSI and the shortest ToF with respect thereto, excluding the tractor subnetwork <NUM> in both cases at steps <NUM> and <NUM>. At step <NUM>, if there is a match, then the respective subnetwork 314b is identified as the second trailer 304b immediately after the lead trailer 304a at step <NUM> as shown on <FIG>. If there is no match at step <NUM>, the method restarts at step <NUM>. In another embodiment, the method restarts at step <NUM> by using the previously established lead trailer identification. If at steps <NUM> and <NUM>, there are only an RSSI and ToF from two subnetworks 314a, 314b, then the tractor subnetwork <NUM> can identify and order the associated two trailers 304a, 304b. In one embodiment, the process end after successful identification at step <NUM>.

Once the second trailer 304b is identified, any of the hubs 330a, 330b or the trailer wireless hub 330c of the second trailer 304b can identify the third trailer 304c. To that end, in the following description the second trailer wireless hub 330c is used. At steps <NUM> and <NUM>, the hub 330c identifies the subnetwork 314c with the highest RSSI and the shortest ToF excluding the tractor subnetwork <NUM> and the lead trailer subnetwork 314a in both cases. At step <NUM>, if there is a match, it is assumed the identified subnetwork 314c corresponds to the third trailer 304c (i.e. the trailer 304c immediately after the second trailer 304b). The third trailer 304c is identified at step <NUM> based on the third trailer subnetwork 314c, as shown on <FIG>. If there is no match at step <NUM>, the entire process is restarted at step <NUM> but may alternatively return to step <NUM>.

The steps to identify the next trailer in a line of trailers can be repeated for additional trailers, as would be understood by one of skill in the art. Assuming the vehicle <NUM> has three trailers 304a-c, as in the example of <FIG>, the first results ordering the three trailers 304a-c have then be determined at step <NUM>, which indicate an initial order of all the trailers 304a-c. If at steps <NUM> and <NUM>, there are only an RSSI and ToF from three subnetworks 314a-c, then the tractor subnetwork <NUM> can identify and order the associated three trailers 304a, 304b and end the method or proceed with a double check as follows. For more trailers, the method may continue.

After step <NUM> to double check, the process of determining the order of the trailers 304a-c is then substantially repeated, in reverse order, to get a second set of results for comparison to determine whether the initial ordering was accurate. In more detail, referring now to <FIG>, the method continues to monitor RSSI and ToF data from all other subnetworks 314a-c at step <NUM>. At steps <NUM> and <NUM>, starting with the identified third trailer 304c, the third trailer subnetwork 314c identifies the subnetwork 314b with the highest RSSI and the shortest ToF by comparing data from all of the identified subnetworks <NUM>, 314a-b. At step <NUM>, subnetwork(s) with the highest RSSI and the shortest ToF are compared. If the identified subnetworks with the highest RSSI and the shortest ToF are different, the method restarts to step <NUM>, but if there is a match, then the identified subnetwork 314b is determined to correspond to the second trailer 304b. The identification of location of the second trailer 304b is saved as part of the second set of results at step <NUM>.

At steps <NUM> and <NUM>, the newly identified second trailer subnetwork 314b then identifies the highest RSSI and the shortest ToF excluding the third trailer subnetwork in both cases. At step <NUM>, the second trailer subnetwork 314b compares the identified subnetworks, typically subnetwork 314a for each criteria. If there is a match, then the identified subnetwork (e.g., subnetwork 314a) is determined to correspond to the lead trailer 304a and saved as part of the second set of results at step <NUM>. If the identified subnetworks are different at step <NUM>, the method restarts at step <NUM>.

Referring now to <FIG>, the identified lead trailer subnetwork 314a then identifies the subnetwork with the highest RSSI and with the shortest ToF excluding the second and third trailer subnetworks 314b-c, in both cases at steps <NUM> and <NUM>. At step <NUM>, the lead trailer subnetwork 314a compares the identified subnetworks. If there is a match, properly being the tractor subnetwork <NUM>, then the method proceeds to step <NUM> where the identified tractor subnetwork <NUM> is determined to correspond to the tractor <NUM>. The method gathers and saves the information related to the three properly located subnetworks <NUM>, 314a-b as part of the second set of results at step <NUM>.

At step <NUM>, with the subnetworks <NUM>, 314a-b identified and ordered a second time, the first and second set of results are then compared. If the ordering determined in the first set of results is consistent with the ordering determined in the second set of results, then it is verified that order of the VAN subnetworks <NUM>, 314a-c have been correctly determined and the method ends at step <NUM>. Otherwise, if the order determined in the first and second set of results is different, then the method starts over at step <NUM> so a verified order can be determined.

In this way, the VAN <NUM> is able to automatically determine an order of the trailers 304a-c based on the order of the subnetworks 330b-d with no input from the user. The order of the trailers 304a-c can then be relied upon to determine where various sensors are located, and to easily take action based on a sensor readings and/or alert. For example, if a tire pressure monitoring sensor reports data that triggers a low pressure alert, it is advantageous for the user to be able to narrow down the potential tire(s) corresponding to that alert. A given sensor's subnet can be used to determine which trailer (or tractor) the sensor is a part of, based on the ordering of the trailers with no additional input needed from the user. Thus, if the pressure sensor reporting the alert is in the third trailer subnetwork 314c, the user can be alerted that a tire of the third trailer 304c has low pressure. This avoids the need for the user to spend time checking the tires for the tractor <NUM> or the other trailers 304a-b. This can be similarly used for readings and alerts for other known sensors as are known in the art.

It is also envisioned that the dollies <NUM> can have wireless hubs that form separate subnetworks rather than part of the trailer subnetworks 314b-c, respectively. In this instance, the dolly subnetworks would be similarly identified and ordered in the method of ordering the subnetworks. The process described herein can use shared specifications for standardized information. The shared specifications allow the process of linking trailers to the VAN <NUM>, <NUM> and ordering the trailers to be easily carried out across multiple truck and trailer brands. Preferably, no secondary user action is required to determine the ordering of the trailers <NUM>, <NUM>. For example, the method for ordering the trailers <NUM>, <NUM> can be activated upon making the electrical and/or pneumatic connections between the tractor <NUM>, <NUM> and the trailers <NUM>, <NUM>, as well as between the trailers <NUM>, <NUM>. The method can also be triggered by using the smart device <NUM>.

Referring now to <FIG>, various brake and sensor arrangements are shown. The sensor arrangements can be incorporated into the VAN <NUM> of <FIG>, as described above. Referring to <FIG>, a sensor arrangement <NUM> is shown. The sensor arrangement <NUM> includes a stationary sensor portion <NUM> and a moving target portion <NUM>. The portions <NUM>, <NUM> are mounted to the brake assembly with the sensor portion <NUM> fixed to a casting or other stationary feature whereas the target portion <NUM> is mounted on a moving feature. Thus, as brakewear occurs and the brakes are engaged, the target portion <NUM> moves with respect to the sensor portion <NUM> commensurate with the brakewear and, in turn, the signal from the sensor portion <NUM> varies to indicate wear. The sensor arrangement <NUM> can be mounted in preset cast location, retrofit on existing assemblies, integrally fabricated with the braking assembly, and combinations thereof. Generally, the sensor arrangement <NUM> is not integrated with a consumable portion so that by being battery powered, the sensor arrangement <NUM> can perform measurements after many other consumable parts (e.g., brake pads) have been replaced many times. It is envisioned that the sensor arrangement <NUM> may require calibration during replacement of parts.

Typically, the range of motion of the target portion <NUM> is limited so that calibration and proper positioning is required so that a leading edge <NUM> of the target portion <NUM> is aligned with a start of travel line <NUM> with no wear. As maximum brakewear approaches, the leading edge <NUM> approximately aligns with an end of travel line <NUM> or less.

Referring now to <FIG>, a floating caliper brake system <NUM> with a sensor assembly <NUM> is shown. The brake system <NUM> is on each end <NUM> of an axle <NUM>. When the brakes are applied, a floating caliper <NUM> moves in a linear direction parallel to motion arrow <NUM> with respect to a fixed carrier <NUM> to force brake pads against a wheel (not distinctly shown). The sensor assembly <NUM> (shown in isolation in <FIG>), includes a fixed sense element <NUM> and a moveably mounted target portion <NUM>. The target portion <NUM> includes a magnet <NUM> while the sense element <NUM> includes an anisotropic magnetic resistivity (AMR) sensor on a printed circuit board (PCB) <NUM> that detects a magnetic field based on the positioning of the magnet <NUM>.

In the example given, the sense element <NUM> is attached to the carrier <NUM> while the target <NUM> is attached to the floating caliper <NUM>. When the brakes are applied, the floating caliper <NUM> moves and the target <NUM>, which is positioned to move parallel to the fixed sense element <NUM>, such that the target <NUM> changes position and/or angle with respect to the sense element <NUM>. The movement of the target <NUM> is measured by the sense element <NUM> and reported to a subnetwork, wireless hub and/or VAN.

The brake pad thickness and/or wear can then be determined based on the measured movement and the range of motion between the floating caliper <NUM> and carrier <NUM>. Measurements from sensors across the vehicle can be matched up with the corresponding location on the vehicle to determine brake pad thickness at various locations. Brake pad thicknesses can be analyzed within the VAN to compute remaining pad thickness and compare that thickness to regulatory allowances.

If the thickness of a brake pad falls below an acceptable level, a warning can be generated within the tractor for the driver, thereby identifying a particular brake pad that needs replacing. Further, the data from one or more sensors can be used to verify a new brake pad from the initial offset measured when the brakes are applied or for wheel-to-wheel comparisons. For example, excessive wear on a single wheel may indicate a sticking caliper so that a maintenance check can be scheduled. Measurements can be stored and analyzed to determine a wear rate and overall slope of brake pad wear over time. Based on the data, maintenance reminders and scheduling is done automatically. Changes in wear rate or slope can be indicative of fault conditions with a given brake, correlated to driver behavior, or attributable to a change in primary driving conditions, and corresponding warnings can be issued to the driver and/or the fleet manager. The positioning of the sense element <NUM> and target portion <NUM> could also be reversed, with the sense element <NUM> attached to the floating caliper <NUM> while the target portion <NUM> is attached to the carrier <NUM>.

Referring now to <FIG>, another brake system <NUM> with a sensor assembly <NUM> is shown. The brake system <NUM> is shown on an axle <NUM> in <FIG>. The brake system <NUM> is a fixed caliper brake system where the brake pad <NUM> moves with respect to the fixed caliper <NUM> shown in more detail and isolation in <FIG>. Therefore, the sense element <NUM> can be attached to the fixed caliper <NUM> with the target portion <NUM> attached to the brake pad <NUM>, or the support structure around the brake pad, to move linearly as the brake pad <NUM> moves. Alternatively, the sense element <NUM> could be attached to the brake pad <NUM> and the target portion <NUM> attached to the fixed caliper <NUM>. Again, the signal from the sense element <NUM> may be wirelessly transmitted. Further, the brake system <NUM> is separate from consumable components and battery powered so that other than possibly needing recalibration, the brake system <NUM> may last for the life of the vehicle. The calibration of the brake system <NUM> is preferably performed automatically or by using a smart device in communication with the vehicle area network.

Referring now to <FIG>, <FIG> is a perspective semi-exploded view of a disc brake system <NUM> in accordance with the subject technology. <FIG> is a different perspective semi-exploded view of the disc brake system <NUM>. <FIG> are detailed views of a brake sensor assembly <NUM>.

The disc brake system <NUM> includes a stationary mounting plate <NUM>. Preferably, the sensor element <NUM> can be mounted to an attachment plate <NUM> (see <FIG>), which can in turn be attached to the stationary mounting plate <NUM> at location <NUM>. The target portion <NUM> mounts on a floating portion of the caliper <NUM>, thereby moving with the pads as the pads wear during braking. A preferred location for mounting the target portion <NUM> is a circular projection <NUM>. As can be seen in <FIG>, the sense element <NUM> and the target portion <NUM> can be retrofit by using brackets <NUM>, <NUM>, respectively. Alternatively, in <FIG>, the target element <NUM> is integrated into the casting <NUM>. For example, the casting <NUM> is part of the circular projection <NUM>.

Referring now to <FIG>, other brake systems and brake sensor assemblies are shown. The systems and sensor assemblies can work as described with respect to systems and sensor assemblies above, except as otherwise described herein. In particular, the brake systems in <FIG> are drum brake systems, and all sensor assemblies shown therein are configured for use with a drum brake system as described below.

Referring now to <FIG>, the vehicle (not shown) includes an axle <NUM> having a brake system <NUM> on each end <NUM>. When the brakes are applied, either by the driver or by command in an autonomous vehicle, an air brake chamber <NUM> actuates a push arm or pushrod <NUM> along motion arrow <NUM>. The movement of the pushrod <NUM> rotates a cam shaft <NUM> that controls movement of the brake pads.

Referring particularly to <FIG>, an exemplary sensor assembly <NUM> is shown on the drum brake system <NUM> and in isolation, respectively. The sensor assembly <NUM> includes a sense element <NUM> and a target portion <NUM>, which can be similar to the other sensors described herein. An air brake chamber <NUM> of the brakes actuates the pushrod <NUM> when the brakes are applied. A fixed brake chamber bracket <NUM> is attached to the brake chamber <NUM>, the pushrod <NUM> extending through an aperture <NUM> in the brake chamber bracket <NUM>. The sense element <NUM> is attached to the chamber bracket <NUM> while the target portion <NUM> is attached to the pushrod <NUM>. When the brakes are applied, the pushrod <NUM> moves, changing the position of the target portion <NUM> relative to the sense element <NUM>. These relative positions are measured and can be used to first calculate chamber stroke and ultimately calculate brake pad wear by means of algorithms that correlate the stroke of the brake chamber <NUM> through the geometry of the slack adjuster, cam shaft/cam, and cam follower. The measured data from the sensor assembly <NUM> can then be used as described with respect to other sensors herein.

Referring now to <FIG>, an exemplary sensor assembly <NUM> for a drum brake system <NUM> is shown on the brake system <NUM> and in isolation, respectively. The sensor assembly <NUM> includes a sense element <NUM> and an arcuate target element <NUM>, which can be similar to the other sensors described herein. The brake system <NUM> includes a pushrod <NUM> that moves parallel to motion arrow <NUM>. The pushrod <NUM> is connected to a slack adjuster head assembly <NUM> so that when the pushrod <NUM> moves, the slack adjuster head assembly <NUM> rotates as shown by motion arrow <NUM>. The target portion <NUM> is mounted on the slack adjuster head assembly <NUM> for rotational motion therewith. The brake system <NUM> also includes a fixed mounting plate <NUM> with the sense element <NUM> coupled thereto.

When the brakes are applied, the pushrod motion <NUM> causes the rotary motion <NUM> of the slack adjuster head assembly <NUM> and, in turn, similar motion of the target portion <NUM>. The sense element <NUM> does not move. Thus, when the brakes are actuated, the position of the target portion <NUM> relative to the sense element <NUM> changes. These relative positions are measured and can be used to calculate brake pad wear by means of algorithms, as are described herein. The measured data from the sensor assembly <NUM> can then be used as described with respect to other sensors herein.

Referring now to <FIG>, another drum brake system <NUM> and exemplary sensor assembly <NUM> are shown. The sensor assembly <NUM> includes a sense element <NUM> and a target portion <NUM>, which can be similar to the other sensors described herein. The drum brake system <NUM> is also similar to the brake system <NUM> described above. The drum brake system <NUM> includes an adapter plate <NUM> coupled to an adjuster arm <NUM>. The adapter plate <NUM> facilitates coupling the sense element <NUM> in a fixed location. The target portion <NUM> is attached to the adjacent moving adjuster arm <NUM>. Alternatively, the adapter plate <NUM> could carry the target portion <NUM> and the sense element <NUM> could be attached to the adjuster arm <NUM>. In either case, the adapter plate <NUM> exemplifies a possible retrofit application.

When the brakes are applied, the pushrod motion <NUM> again causes a rotary motion <NUM> of the slack adjuster arm <NUM>. In the example given, the target portion <NUM> is attached to the moving adjuster arm <NUM> and the sense element <NUM> is fixed to the stationary adaptor plate <NUM>. Therefore, when the brakes are applied, the position of the target portion <NUM> relative to the sense element <NUM> changes. These relative positions are measured and can be used to calculate brake pad wear by means of algorithms as described herein. The measured data from the sensor can then be used as described with respect to other sensors herein.

Referring now to <FIG>, yet another drum brake system <NUM> with an exemplary sensor assembly <NUM> are shown. The sensor assembly <NUM> includes a sense element <NUM> and a target portion <NUM>, which can be similar to the other sensors described herein. The drum brake system <NUM> is also similar to drum brake system <NUM>. The drum brake system <NUM> includes an indicator plate <NUM> coupled to a cam shaft <NUM>.

When the brakes are actuated, the cam shaft <NUM> rotates along arrow <NUM> to cause the brake pads to contact the drum. The target portion <NUM> is attached to the indicator plate <NUM> which does not move in response to the brake pads being applied. However, the sense element <NUM> is attached to the adjuster arm <NUM> which moves when the cam shaft <NUM> rotates. Therefore, when the brakes actuate, the position of the target portion <NUM> relative to the sense element <NUM> changes. These relative positions are measured and can be used to calculate brake pad wear by means of algorithms similar to those described herein. The measured data from the sensor can then be used as described with respect to other sensors herein.

Referring now to <FIG>, the end of a drum brake system <NUM> which is normally proximate a wheel is shown. The drum brake system <NUM> can include the other components of drum brake systems as are described herein, and can be incorporated as part of any other drum brake system described herein. As described above, when the brakes are applied, actuation of the pushrod translates into rotation of a cam shaft (e.g. rotation of shaft <NUM> in <FIG>). This results in rotation of an s-cam <NUM> on the end of the cam shaft. The drum brake system <NUM> includes opposing brake shoes <NUM> which are configured to pivot around anchor pins <NUM>. On the end distal from the anchor pins <NUM>, each brake shoe <NUM> includes a cam follower <NUM>. Rotation of the s-cam <NUM> engages the cam followers <NUM>, forcing the brake shoes <NUM> outward along motion line <NUM>. When the brake system <NUM> is fixed within a wheel during normal operation, the outward movement of the brake shoes <NUM> causes the brake linings <NUM> to engage the wheel and stop movement of the wheel.

Referring now to <FIG>, a comparison is shown of the positioning of the s-cam <NUM> with the brakes disengaged in image <NUM> and with the brakes engaged in image <NUM>. As can be seen, the cam followers <NUM> are separated by first distance D1 when the brakes are disengaged. When the brakes are engaged, cam followers <NUM> slide along the rotating s-cam <NUM> and reach a final separation distance D2 as the brakes are fully engaged. To show the rotational movement of the s-cam <NUM>, a phantom image of the s-cam <NUM> in the original disengaged position with the brakes disengaged is shown in dashed lines superimposed over the final s-cam <NUM> position in the example showing the brakes engaged <NUM>. In the engaged position in the example shown, the s-cam <NUM> has rotated roughly <NUM> degrees between the disengaged and engaged positions of images <NUM>, <NUM>. As the brake pads wear, greater total rotation becomes required to fully engage the brakes.

Referring now to <FIG>, examples of typical positions of s-cams and cam followers are shown over life span of the brakes. In particular, <FIG> represents s-cam and cam follower positioning for a new brake, <FIG> represents s-cam and cam follower positioning for a brake near the middle of the brake life cycle, and <FIG> represents s-cam and cam follower positioning for a brake near the end of the brake life. In each <FIG>, the s-cam <NUM> and cam followers <NUM>, in dashed lines, represent the positioning for a disengaged brake system, while the s-cam <NUM> and cam followers <NUM> represent the positioning for an engaged brake system. The slack adjuster of the braking system includes an adjuster mechanism that automatically compensates for brake pad wear by adjusting the positioning of the s-cam <NUM> over the life of the brakes. In the example given, the slack adjuster seeks to keep the s-cam <NUM> positioned such that approximately <NUM> degrees of rotation of the s-cam <NUM> occurs between the disengaged s-cam <NUM> and the engaged cam <NUM>. As the pads wear, the rotation required to fully engage the brakes increases. As can be seen, the s-cam <NUM>, <NUM> position varies with wear so that the separation D1, D2, D3 between the cams <NUM>, <NUM> increases with increased wear, with separation D3 > D2 > D1. Through this process, the opposing arcuate portions <NUM>, <NUM> of the s-cam <NUM>, <NUM> continue to interact with cam followers <NUM>, <NUM> when the breaks are applied.

Referring now to <FIG>, a graph <NUM> of cam follower displacement at various s-cam rotations is shown. The concentric circles <NUM> are zeroed at the center of the graph <NUM> and represent a growing displacement between opposing cam followers in mm as the concentric circles <NUM> approach the perimeter of the graph <NUM>. The circular perimeter <NUM> represents a displacement distance of the s-cam <NUM>. The plot points <NUM> represent the displacement of the cam followers at s-cam angle increments of <NUM> degrees. For ease of explanation, the values of the cam follower displacement at each s-cam angle plotted are then consolidated in a table <NUM>.

Referring now to <FIG>, the table <NUM> is plotted in a typical line graph format in graph <NUM>. The x-axis represents rotation angle of the s-cam in degrees, while the y-axis represents displacement distance between the cam followers in mm. The plot points <NUM> are the values shown in the table <NUM>, which are also the plot points <NUM> of the graph <NUM>. A trend line <NUM> can then be formed between the plot points <NUM>. An equation <NUM> of the trend line <NUM> can be calculated. At any given point of the brake life, brake pad thickness can then be calculated using the difference between the current cam follower separation and the initial cam follower separation when the brakes were new. This is done in accordance with the following equation: <MAT>.

In Equation <NUM>, Thickness is the current calculated brake thickness to be determined, ti is the initial brake pad thickness, m is the slope of the trend line <NUM>, θn is the current s-cam angle, and θi is the initial s-cam angle. For example, if the initial s-cam angle for a brake system was <NUM> degrees, and the initial brake bad thickness was <NUM>, and assuming a graph slope of <NUM> as calculated in <FIG>, Equation <NUM> for a current s-cam angle of <NUM> degrees would yield the following: Thickness = <NUM> - <NUM> (<NUM> - <NUM>) = <NUM>. Thus, when the s-cam rotation is at an angle of <NUM> degrees, the current brake pad thickness is determined to be <NUM>. This process can be repeated at different s-cam angles over the brake life to determine a brake pad replacement timing well in advance of brake failure. Notably, initial and current s-cam angles and cam follower displacement should be compared during like braking states (i.e. disengaged or engaged). In general, this process can be employed as an algorithm in connection with the braking systems described herein and used to calculate brake pad wear. As such, various sensors can be employed to gather data related to the s-cam rotational position, including any of the other position sensors described herein.

Based on the thickness calculations described above, a corresponding alert or message can be displayed for the user, indicating current brake pad thickness, wear, and/or likely miles until failure or recommended maintenance based additionally on the miles traveled to reach the current level of wear and likely level of brake pad failure. For example, assume the brake pad had worn from <NUM> to <NUM> in thickness over the first <NUM>,<NUM> miles traveled, and brake pad failure is assumed to occur at <NUM>. The brake system could include an algorithm to interpolate between the initial brake pad thickness of <NUM> to the expected failure thickness of <NUM> to determine that the brake pads were likely to reach <NUM>, and therefore fail, in another <NUM>,<NUM> miles. The remaining miles until expected brake pad failure could be displayed to the user constantly, or the system could be configured to automatically generate display a warning or alert a certain number of miles in advance of the expected failure point. The system could also factor in more advanced driving variables, such as the effects of city versus highway driving, the vehicle load, or other variables likely to cause non-uniform wear. The system could also aggregate and compare data from all brake sensors, comparing brake pad wear across all wheels to identify outliers which may be indicative of abnormalities and alerting the user of the wheels with potential faults. For example, a dragging brake will likely cause faster brake pad wear than the other brakes.

Information from the sensors as discussed above can be used in various contexts. Maintenance planning personnel can rely on the information for scheduling purposes. If the vehicle normally travels longer routes, brake pad replacement can be planned either before, or during a long trip based on the expected miles until brake pad failure. Information can also be provided to a fleet operator, as one of a larger group of indicators related to a trailer's road readiness. If the brake pads are likely to fail at some point during the expected truck route, the indicator can alert the fleet operator to this fact so that maintenance can be performed beforehand.

In should be understood all sensors described herein are configured for use in a VAN and as part of a system as described herein. In other embodiments, the sensor assemblies may utilize other contactless technology to determine the distance, such as optical devices, capacitive sensors, inductive sensors, sonar, radar and the like. Anisotropic magnetoresistance (AMR) and tunnel magnetoresistance (TMR) are also particularly well-suited for the subject technology because these methods consume little power in battery-based sensor assemblies.

As can be seen, the subject technology can be initially integrated into the brake structure or retrofit. In either case, the brake sensor is preferably not consumable. The brake sensor may have ample battery life to last for the life of the vehicle.

Referring now to <FIG>, a schematic view of a vehicle area network (VAN) <NUM> with integrated brake sensor assemblies <NUM> is shown. The VAN <NUM> is similar to that described above with respect to <FIG> and similar numbers in the "<NUM>" are used to designate similar components, not all of which are described again in detail. The brake sensor assemblies <NUM> are each coupled to a wheel <NUM>. The VAN <NUM> is in communication with a data repository <NUM>. The data repository <NUM> may be integral with the tractor <NUM> and/or at an external remote device (e.g., a server) as depicted, which the VAN can communicate with through a telematics device or the like.

As noted above, the sensors <NUM> can remain in use after brake pad replacement. However, upon initial installation or at a change of brake pads, the sensors <NUM> will typically require calibration. Calibration establishes the baseline for all subsequent measurements and by which the remaining pad thickness is determined. In one embodiment, the sensors <NUM> are capable of measuring a total span of <NUM>. Of that span, about <NUM> to <NUM> is the friction pad thickness. With a new pad, the sensors <NUM> are 'zeroed' so that relative movement indicating wear can be subtracted from the pad thickness to result in the remaining thickness by the repository <NUM>. Absolute position of the target element can be measured but relative position will be computed and recorded. Preferably, when new pads are installed or at the original commissioning, the sensors <NUM> read close to zero absolute position to allow for the most useable measurement range over the life of the pad wear. If for example the data repository <NUM> determines that the sensor absolute position is not within a predetermined tolerance with a new brake pad, the data repository can generate an out of tolerance 'zero' point indicating problems such as an incorrect sensor installation or that brake pads were installed with less than full-life thickness.

As the data repository <NUM> receives information for the sensors <NUM>, the data repository <NUM> improves the utilization, performance, and safety of the vehicle. For example, the data repository <NUM> can determine a minimum brake pad thickness for comparison to a predetermined threshold. As brake pad wear is typically gradual, warnings can be provided to schedule replacement. The service team can pre-program levels for the warnings and alerts so breaching any legal or manufacturer suggested minimums is avoided. In one embodiment, the tractor dashboard may display a 'miles remaining' indicator before brake pad replacement is needed which is based on rate of brake pad wear captured over certain distances over time. The 'miles remaining' indicator may also be sent to one or more smart devices (e.g., desktop computers, smart phones and the like). The data repository <NUM> aggregates all the brake sensors <NUM> to compare the performance of each brake to the others. Thus, abnormal wear can be determined to uncover potential problems like a dragging brake or unbalanced force differential wearing more quickly than others.

The data repository <NUM> can also include information about the type of routes typically covered by a particular vehicle or company. For example, a <NUM> mile per trip would not need the same warnings and alerts for 'miles to service' as a <NUM> mile trip. For a longer trip, a mid-trip service may even be scheduled into the delivery timetable. Although the sensor readings are real-time or near real-time, the measurements may be provided periodically to preserve sensor battery life. With such constant monitoring, the data repository <NUM> can beneficially use statistical modeling and use averages to minimize false nuisance alerts. The continuous stream of data allows for an actual status check prior to any trip, which goes beyond just a visual inspection.

Additionally, brake wear may be an advanced insight of driver behavior. Expected brake pad compression given the brake pad pressure load or degree to which the brakes were applied (e.g., the brake pads will be expected to compress to different degrees if the user lightly taps the brakes versus if they slam on the brakes for an emergency stop). Notably, this requires some input data regarding the degree to which the brakes were applied during one or more braking events. The second sensor reading can then be compared to an expected second sensor reading and if there is a significant deviation. Whether a particular deviation is significant can be determined on a case by case basis or based on compiled data for past known deviations from that particular vehicle or from a number of vehicles.

The sensors <NUM> can also include temperature sensors. The temperature sensors may be internal to the brake pad wear sensor and/or a separate probe connected to or near the brake wear sensor. The temperature probe can be wired to the brake wear sensor so that the temperature data can be combined with the brake data for transmission. The data can then be transmitted to the range extenders <NUM>, and ultimately to the data repository <NUM> and/or the tractor <NUM> for display or generating a control command in an autonomous vehicle.

Temperature data is particularly insightful for brakes because brakes generate a significant amount of heat when operating properly and even more during heavy duty operation such as during steep downhill descents with a full load. Since brake pads lose some stopping power (coefficient of friction) as temperature rises, the driver can be warned to use the engine to slow the vehicle or the autonomous vehicle can make a similar adjustment. It is also possible for the brake pads to glaze and permanently degrade performance if temperatures are too high. Further, the heat generated by the brakes can result in damage to nearby components (e.g., ABS components) or in a more severe case, wheel end fires. By continuously monitoring temperature, warnings and proper action can be taken to avoid a reduction in braking potential that results in a longer required stopping distance. Still further, the data repository <NUM> can generate alerts and/or change in drive control settings to avoid permanent damage to the brake pads and potentially the rotors due to excessive temperature. In the most extreme case, the data repository <NUM> can warn of temperatures that could soon result in a wheel end fire due to ignition of the grease/oil or even the tire. In some cases, temperature sensors can also include ambient temperature sensors so that temperature sensor reading of the brake system can be normalized for ambient driving conditions.

<FIG> is an exemplary graph <NUM> of temperature in Celsius as measured by brake pad temperature sensors over cumulative driving time. When there is a significant spike in brake pad temperature, as indicated within block <NUM> a processor, such as the wireless hub within the vehicle, can perform anomaly detection dependency modeling as shown in <FIG>.

Claim 1:
A system for measuring brake data from a drum brake assembly (<NUM>) of a vehicle (<NUM>,<NUM>), the drum brake assembly (<NUM>) including a brake chamber (<NUM>) which actuates a push rod (<NUM>,<NUM>) when vehicle brakes are applied, actuation of the push rod (<NUM>,<NUM>) causing a rotary motion of an adjuster arm (<NUM>,<NUM>) and attached slack adjuster head (<NUM>) around a cam shaft (<NUM>), the system characterized by:
a brake sensor (<NUM>) mounted to the drum brake assembly (<NUM>) and configured to measure brake data including a displacement of the drum brake assembly (<NUM>) during braking, the brake sensor (<NUM>) configured to transmit the brake data over a wireless vehicle area network (<NUM>),
wherein the drum brake assembly (<NUM>) is configured to rotate an s-cam (<NUM>) when the brakes are applied such that the s-cam (<NUM>) engages two cam followers (<NUM>) coupled to opposing brake shoes (<NUM>), and
wherein the displacement of the drum brake assembly (<NUM>) is representative of a difference in displacement distance between the two cam followers (<NUM>) when the brake assembly is in a disengaged state and when the brake assembly is in an engaged state.