Wireless Vehicular Area Network with Connected Brake Sensors

Abstract

The present invention discloses a system for measuring braking data from a braking assembly of a vehicle. The braking assembly includes a floating portion that moves relative to brake pad wear. The system includes a braking sensor for each wheel. The braking sensor includes a fixed sensing element and a target portion connected to move with the floating portion. The sensing element generates a signal indicative of the position of the target portion. The signal is used to determine the brake pad thickness. The braking sensor also transmits the signal via a wireless vehicle area network for reception and processing by a wireless hub in the vehicle area network. The vehicle area network can generate and send warnings and / or instructions for an autonomous vehicle based on the signal.

Description

Technical Field

[0001] The present subject matter relates to wireless networks and, in particular, to a braking sensor connected to a vehicular area network. Background Art

[0002] 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 is part of the National Highway System of the United States. The construction of the Interstate Highway System was authorized by the Federal-Aid Highway Act of 1956. The Interstate Highway System spans the contiguous United States and has routes in Hawaii, Alaska, and Puerto Rico.

[0003] With good roads, trucking is an important part of the economic infrastructure. In fact, tractor-trailers cruising on the interstate highways are common. Trucking involves the delivery of not only almost all consumer goods but also industrial products. Truck drivers are usually independent drivers who may or may not own their own trailers but, in any case, contract to deliver one or more fully or partially loaded trailers. In fact, truck driver is one of the most common jobs in the United States.

[0004] As asphalt highways integrate into the information age, a paradigm shift is coming. Such vehicles will be equipped with a set of technologies to connect to the information highway and image the physical highway. The vehicle will form a virtual image of the road, which is processed for navigation and control. The technology will include cameras, LIDAR, RADAR, various sensors, motors, and of course significant processing capabilities (such as processors, memories, power supplies, etc.).

[0005] Despite long-term and ubiquitous use, problems with tractor-trailer transportation still exist. Moving vehicles have made slow progress in fully leveraging the potential benefits of interconnectivity and analytics. Other obstacles stem from the fact that typical drivers are not accustomed to using complex electronic devices or various configurations that are not interoperable for navigation. Additionally, without a driver, more tasks and maintenance activities must be automated. Therefore, there is a need for simple, automatic connection and operation of vehicles that use more complex communication and networking technologies on vehicles, especially tractor-trailer vehicles.

[0006] Various types of sensors have been used on vehicles and, in particular, on tractor-trailer trucks. Typically, these sensors are placed on tractor-trailer trucks and manually calibrated to trigger a general warning (such as a tire pressure warning) when returning a specific measurement value. This requires initial testing and calibration of the sensors on the vehicle. The utility of each sensor is limited to selectively triggering a warning and does not collect or process data from the sensor for analysis.

[0007] In addition, placing sensors adequately in existing vehicle systems, such as braking systems, presents challenges. It is difficult to place one or more sensors within an existing braking system without potentially affecting the integrity of the braking system. Further, components for indicating brake wear are typically integrated into consumable parts, such as the brake pads themselves. Thus, when the brake pads are replaced, the sensor components are also replaced. SUMMARY OF THE INVENTION

[0008] In accordance with the foregoing needs, in at least one aspect, the subject technology relates to a plurality of brake sensors that are directly connected to a vehicle's brake components and report data to a wireless hub via a wireless vehicle area network. Further, the sensor assembly is separated from the consumable part, so use is not interrupted by routine repair and maintenance.

[0009] In at least one aspect, the subject technology includes a system for measuring brake data from a brake assembly of a vehicle, the brake assembly including at least one caliper having a fixed portion and a floating portion. The system includes a plurality of brake sensors. Each brake sensor is connected to one of the calipers and includes a sensing element connected to the fixed portion and a target portion connected to the floating portion. The brake sensors are configured to measure brake data, the brake data including the position of the target portion relative to the sensing element, which indicates brake pad thickness. The brake sensors are further configured to transmit the brake data via a wireless vehicle area network. The system further includes a wireless hub that includes a transceiver configured to send and receive data via the wireless vehicle area network. The wireless hub is configured to receive the brake data from the plurality of brake sensors, process the brake data, and generate and send a warning when the brake data from one of the plurality of brake sensors indicates a potential fault condition.

[0010] In some embodiments, the target portion is a magnet that generates a magnetic field and the sensing element is an anisotropic magnetoresistive sensor configured to sense the magnetic field of the magnet to generate a signal.

[0011] In at least one aspect, the subject technology relates to a system for measuring brake data from a brake assembly of a vehicle. The brake assembly includes a caliper having a fixed portion and a floating portion. The caliper further includes a mounting plate configured to connect the caliper to the vehicle's axle. The system includes a brake sensor mounted on the caliper on the inner side of the mounting plate such that the brake sensor is positioned inside the caliper. The brake sensor includes a sensing element connected to the fixed portion and a target portion connected to the floating portion. The brake sensor is configured to measure brake data and transmit the brake data via a wireless vehicle area network, the brake data including the position of the fixed portion relative to the floating portion.

[0012] In some embodiments, the system includes a wireless hub having a transceiver configured to send and receive data via a wireless vehicle area network. The wireless hub is configured to receive brake data from a plurality of brake sensors, process the brake data, and generate and send a warning when the brake data from one of the plurality of brake sensors indicates a potential fault condition.

[0013] In some embodiments, the braking system further includes at least one temperature sensor. In such a case, the wireless hub can also be configured to detect an anomaly in the temperature measured by the at least one temperature sensor over a period of time. After detecting the anomaly, the wireless hub can compare the temperature measured by the at least one temperature sensor during the period with temperature data from at least one wheel end temperature sensor. When the comparison indicates a fault condition, the wireless hub can then generate and send a warning.

[0014] In at least one aspect, the present subject matter technology relates to a system for measuring brake data from a drum brake assembly of a vehicle, the drum brake assembly including a brake chamber that drives a push rod when the vehicle brake is applied, and the driving of the push rod causes a rotational movement of an adjusting arm and a connected slack adjuster head about a camshaft. The system includes a brake sensor mounted to the drum brake assembly and configured to measure brake data including the displacement of the drum brake assembly during braking. The brake sensor is configured to transmit the brake data via a wireless vehicle area network.

[0015] In some embodiments, the brake sensor includes a sensing element and a target, the sensing element being configured to sense a magnetic field of the target. The sensing element can be connected to a fixed brake chamber bracket that remains in a fixed position relative to the vehicle when the vehicle brake is applied. In such a case, the target is connected to the push rod and configured to move relative to the sensing element when the vehicle brake is applied.

[0016] In some embodiments, the sensing element is connected to a fixed mounting plate adjacent to the slack adjuster head that remains in a fixed position relative to the vehicle when the vehicle brake is applied. In such a case, the target is connected to the slack adjuster head and configured to move relative to the sensing element when the vehicle brake is applied.

[0017] In some embodiments, the target is connected to a fixed indicator plate near the camshaft that remains in a fixed position relative to the vehicle when the vehicle brake is applied. In such a case, the sensing element is connected to the adjusting arm such that when the vehicle brake is applied, the sensing element moves as the adjusting arm and the camshaft rotate.

[0018] In some embodiments, the drum brake assembly is configured to rotate an S-shaped cam when the brake is applied such that the S-shaped 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 represents the 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 may also be configured to measure the S-shaped cam rotation angle and calculate the difference in displacement distance between the two cam followers based on the S-shaped cam rotation angle.

[0019] In some embodiments, the system is configured to determine the current brake lining thickness by calibrating the drum brake assembly at an initial brake lining thickness (ti) and an initial S-shaped cam rotation angle (θi). The system determines the slope of the curve of cam follower displacement versus S-shaped cam rotation angle (m). The system measures the current S-shaped cam rotation angle (θn). Finally, the system calculates the current brake pad thickness by setting it equal to: ti - m(θn - θi). In some cases, the system is configured to provide a warning based on an expected brake pad failure thickness. In some cases, the system is configured to provide one or more of the following metrics: the distance recommended before maintenance of the drum brake assembly; or the distance expected until failure of the drum brake assembly. Actual data regarding specific driver habits and / or expected routes may also be used in the maintenance calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To make it easier for those of ordinary skill in the art to which the present disclosure systems pertain to understand how to make and use the systems, reference is made to the following drawings.

[0021] Figure 1 is an exemplary tractor-trailer vehicle utilizing a vehicular area network according to the present subject technology.

[0022] Figure 2A is an exploded view of a wireless hub according to the present subject technology.

[0023] Figure 2B is a schematic block diagram of a wireless hub according to the present subject technology.

[0024] Figure 3A is an exploded view of a range extender according to the present subject technology.

[0025] Figure 3B is a schematic block diagram of a range extender according to the present subject technology.

[0026] Figure 4A is a perspective view of a beacon according to the present subject technology.

[0027] Figure 4B is an exploded view of a beacon according to the present subject technology.

[0028] Figure 5 is another exemplary tractor-trailer vehicle utilizing a vehicular area network according to the present subject matter technology.

[0029] Figure 6A is part of a flowchart of a trailer of a vehicle with automatic sorting according to the present subject matter technology Figure 5 of the vehicle.

[0030] Figure 6B is part of a flowchart of a trailer of a vehicle with automatic sorting according to the present subject matter technology Figure 5 of the vehicle.

[0031] Figure 6C is part of a flowchart of a trailer of a vehicle with automatic sorting according to the present subject matter technology Figure 5 of the vehicle.

[0032] Figure 6D is part of a flowchart of a trailer of a vehicle with automatic sorting according to the present subject matter technology Figure 5 of the vehicle.

[0033] Figure 7A is a perspective view of a sensor arrangement according to the present subject matter technology.

[0034] Figure 7B is Figure 7A two side-by-side top views of the sensor arrangement after initial installation orientation and full brake wear orientation to illustrate how the target portion moves.

[0035] Figure 8A is a perspective view of an axle with a braking system having a brake sensor assembly according to the present subject matter technology.

[0036] Figure 8B is a detailed perspective view of a braking system having a brake sensor assembly according to the present subject matter technology.

[0037] Figure 8C is an isolated view of a brake sensor assembly according to the present subject matter technology.

[0038] Figure 9A is a perspective view of an axle with a braking system having a brake sensor assembly according to the present subject matter technology.

[0039] Figure 9B is a detailed perspective view of a braking system having a brake sensor assembly according to the present subject matter technology.

[0040] Figure 9C is Figure 9B an isolated view of the brake sensor assembly.

[0041] Figure 10Ais a perspective semi-exploded view of a disc brake system according to the present subject matter technology.

[0042] Figure 10B is a different perspective semi-exploded view of a disc brake system according to the present subject matter technology.

[0043] Figure 10C is a detailed perspective view of a brake system with a brake sensor assembly according to the present subject matter technology.

[0044] Figure 10D is a model view of a deployed brake sensor assembly according to the present subject matter technology.

[0045] Figure 10E is a partial view of a deployed brake sensor assembly according to the present subject matter technology.

[0046] Figure 11 is a perspective view of a shaft with drum brake systems at each end according to the present subject matter technology.

[0047] Figure 12 is a separated perspective view of a drum brake system according to the present subject matter technology.

[0048] Figure 13 is an isolated view of a brake sensor assembly according to the present subject matter technology.

[0049] Figure 14 is an end view of a drum brake system according to the present subject matter technology.

[0050] Figure 15 is Figure 14 a separated perspective view of the sensor assembly of the drum brake system.

[0051] Figure 16 is an end view of a drum brake system according to the present subject matter technology.

[0052] Figure 17 is Figure 16 a separated perspective view of the sensor assembly of the drum brake system.

[0053] Figure 18 is an end view of a drum brake system according to the present subject matter technology.

[0054] Figure 19 is for Figure 18 a separated perspective view of the sensor assembly of the drum brake system.

[0055] Figure 20A is a perspective view of a drum brake system according to the present subject matter technology.

[0056] Figure 20BShows two end views of a drum brake system according to the present subject matter technology, where the brake is in a disengaged and engaged state for comparison.

[0057] Figure 20C - 20E is Figure 20A A schematic diagram of the exemplary positioning of the S-shaped cam and cam follower of a drum brake system at various positions of the brake shoe from new to end-of-life.

[0058] Figure 20F is Figure 20A A mapping diagram of the cam follower displacement of a drum brake system during various S-shaped cam rotations.

[0059] Figure 20G is a depiction of Figure 20A The graph of the cam follower displacement of a drum brake system during various S-shaped cam rotations.

[0060] Figure 21 Is a schematic diagram of a vehicle with a vehicle area network having an integrated brake sensor assembly according to the present subject matter technology.

[0061] Figure 22A Is an example graph of the brake pad temperature of a brake system according to the present subject matter technology versus driving time.

[0062] Figure 22B Is an exemplary graph showing the variation of the brake pad temperature and wheel end temperature of a comparative brake system according to the present subject matter technology versus driving time. Detailed Description

[0063] The present subject matter 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 apparent to those of ordinary skill in the art from the following detailed description of certain preferred embodiments in conjunction with the drawings that illustrate representative embodiments of the invention. The same reference numerals are used herein to denote the same components. Additionally, words indicating directions such as "upper", "lower", "distal", and "proximal" are used only to assist in describing the position of components relative to each other. For example, the "upper" surface of a part is used only to describe the surface that is separated from the "lower" surface of the same part. No words indicating direction are used to describe an absolute direction (i.e., the "upper" part must always be at a higher elevation).

[0064] Now referring to Figure 1, an exemplary vehicle 100 is shown using a vehicle area network (VAN) 101 according to the present subject matter. Vehicle 100 has a tractor 102 for towing two trailers 104a, 104b. Tractor 102 can tow only one trailer or multiple trailers, up to five. The responsibilities of a truck driver typically include not only ensuring the safe and proper operation of vehicle 100, but also connecting and disconnecting trailers 104a, 104b. Tractor 102 also includes a cab 103 having a dashboard (not explicitly shown) for presenting information related to trailers 104a, 104b. Tractor 102 has front wheels 105a that can be maneuvered to control the direction of tractor 102. Tractor 102 also has rear wheels 105b. A dolly 106 facilitates the mechanical connection of the first and second trailers 104a, 104b. Trailers 104a, 104b and dolly 106 also include wheels 107.

[0065] Trailers 104a, 104b and dolly 106 are equipped with multiple sensors for monitoring position, speed, temperature, pressure, weight, etc. for various purposes. In Figure 1 , components of VAN 101 such as sensors 110a - 110c are schematically shown to illustrate possible locations and configurations. The driver is equipped with a pairing device 275 for wirelessly connecting to VAN 101 and sensors 110. Pairing device 275 can also monitor the status of trailers 104a, 104b and devices connected to VAN 101. Pairing device 275 can be a tablet computer, a smart phone, a dedicated controller, etc.

[0066] VAN 101 establishes communication between multiple components of vehicle 100. The individual components can be connected wirelessly, wired, and combinations thereof. The connections can utilize various communication protocols, as will be discussed in more detail herein. VAN 101 can utilize WiFi to establish a high - bandwidth backbone, effectively the first level of VAN 101. VAN 101 can include any number of sub - networks, effectively the second level of VAN 101. For example, as Figure 1 shown, VAN 101 includes a tractor sub - network 112 and a trailer sub - network 114. Each sub - network 112, 114 includes one or more wireless hubs 130a - 130d. The first trailer 104a includes wireless hub 130b, the dolly 106 includes wireless hub 130c and the second trailer 104b includes wireless hub 130d. Since tractors 102, trailers 104a, 104 and dolly 106 are often reconfigured with other trailers and dollies, it is advantageous to have quick and easy pairing to establish subsequent vehicle area networks.

[0067] VAN 101 also includes a first remote communication module 116a on the tractor 102 and communicating with the tractor hub 130a, and a second remote communication module 116b on the first trailer 104 and communicating with the first trailer hub 130b. The remote communication modules 116a, 116b also communicate with an external network 118 having external devices 120. The remote communication modules 116a, 116b communicate with the external network 118 via a cellular tower 122. Preferably, the tractor 102 has a chassis CAN bus 124 through which the tractor hub 130a and the remote communication module 116a communicate. The trailers 104a, 104b can be configured substantially the same or completely differently, both in terms of hardware and software. However, VAN 101 can automatically integrate components so that few (if any) pairing activities with the smart device 275 are required of the driver. Remote communication modules and services are available from a number of suppliers, such as Cal Amp of Irvine, California.

[0068] The wireless hubs 130a - 130d are powered by a wired power line communication (PLC) cable, typically connected by the driver when mechanically coupling the trailers 104a, 104b to the tractor 102. The wireless hubs 130a - 130d communicate using WiFi with an 802.15.4 thread network protocol and / or via the CAN bus 124. The wireless hubs 130a - 130d can also communicate via common low - power friendly means such as Bluetooth or 433Mhz technology. The wireless hubs 130a - 130d can also use near - field communication and any other wireless communication protocol known now or developed later.

[0069] The hubs 130a - 130d can be connected to one or more components or to each other using a wired connection. For example, the tractor hub 130a can be connected to the front trailer hub 130b by a wired cable connection. The wired cable connection can optionally provide power from the tractor hub 130a to the trailer hub 130b while allowing communication via PLC technology. The wired connection can allow the tractor hub 130a and the first trailer hub 130b to automatically pair when physically connected. During pairing, the hubs 130a, 130b communicate and connect using the PLC connection according to out - of - band pairing techniques to share the credentials of VAN101. Similarly, the hubs 130c, 130d can also be hard - wired and automatically integrated into VAN 101.

[0070] Each wireless hub 130a - 130d acts as a central communication or access point for devices within the respective local area network or subnet 112, 114 of the vehicle 100. To this end, the tractor wireless hub 130a creates a tractor subnet 112 for all devices in and around the tractor 102 of the vehicle 100. Similarly, the first trailer hub 130b creates a trailer subnet 114 for all devices in and around the first trailer 104a. Additionally, the wireless hub 130c on the flatbed 106 is part of the first trailer subnet 114 but can even form another subnet. Other subnets can also be included, for example, for other additional trailers, flatbeds, and / or truck areas.

[0071] Still referring to Figure 1 , the tractor wireless hub 130a establishes communications to the tractor remote communication module 116a, paired device 275, and the first trailer wireless hub 130b to create the tractor subnet 112. The tractor hub 130a can communicate with the first trailer hub 130b via PLC and / or WiFi, communicate with the paired device 275 via WiFi, and communicate with the remote communication module 116a via the CAN bus 124. In one embodiment, the tractor hub 130a uses Thread networking communication technology based on the IEEE802.15.4 radio standard to achieve low power consumption and latency. The communication protocol can include AES128 encryption with a Media Access Control (MAC) layer network key.

[0072] The tractor 102 also includes a plurality of sensors 110a. For simplicity, Figure 1 only one sensor 110a is schematically shown in , but represents any type of sensor at any location. To facilitate communication between the tractor hub 130a and the sensor 110a, the tractor subnet 112 can include a range extender transmitter / receiver 170a paired with the sensor 110a. Depending on the sensor configuration, the sensor 110a can also communicate directly with the tractor hub 130a. The transmitter / receiver 170a and the sensor 110a can utilize Thread networking communication technology and the like.

[0073] For example, the communication between the transmitter / receiver 170a and the sensor 110a can be via Bluetooth communication. The transmitter / receiver 170a acts as a range extender for the sensor 110a. However, Bluetooth is vulnerable to eavesdropping, so out-of-band (OOB) pairing is required. The paired device 275 is used to complete the OOB pairing. The paired device 275 can use Near Field Communication (NFC) with the hubs 130a - 130d, sensors 110a - 110d, and transmitter / receivers 170a - 170d.

[0074] A variety of techniques and any combination of techniques can be used to pair components 110a - 110d, 130a - 130d, 170a - 170d. The examples given here are based on the normal debugging / pairing process of thread devices. The pairing device 275 can use WiFi or even read barcodes to link to the hub 130a. Once linked to the hub 130a, the pairing device 275 can use RFID technologies such as NFC tags to establish an OOB (out-of-band) pairing connection to the transmitter / receiver 170a and the sensor 110a. NFC technology is desirable because the pairing device 275 can simply be a smart phone running an application and staying near the transmitter / receiver 170a or the sensor 110a. The OOB pairing link can use Datagram Transport Layer Security (DTLS), which is a communication protocol that provides security by allowing communication in a way designed to prevent eavesdropping, tampering, and message forgery. Additionally, a pre-shared key (PSK) generated by an algorithm such as J-PAKE can be used to secure access.

[0075] Once the pairing device 275 establishes communication between the hub 130a, the sensor 110a, and the transmitter / receiver 170a, the tow vehicle subnet 112 is established. In a similar manner, the trailer subnet 114 can be established. The first trailer hub 130b establishes the first trailer subnet 114 which also includes a plurality of sensors 110b. For simplicity, only a single sensor 110b, e.g., a TPMS, is shown schematically. The transmitter / receiver 170b is paired with the sensor 110b. The first trailer 104a also includes a remote communication module 116b and a beacon 200, both of which are part of the first trailer subnet 114. The remote communication module 116b also communicates with the external network 118 via the cellular tower 122. The beacon 200 can also communicate directly with the tow vehicle hub 130a, either wired or wirelessly.

[0076] The tow vehicle hub 130a is also paired with the trailer hub 130b such that the corresponding subnets 112, 114 are in secure communication. To pair the hubs 130a, 130b, the OOB pairing link can use a physical connection compliant with ISO 11992, which is a CAN-based vehicle bus standard in the heavy truck industry for communication between a tow vehicle and one or more trailers. The pairing of the hubs 130a, 130b can share a unique data key, e.g., a key generated by AES-128 encryption.

[0077] The beacon 200 provides a separate means of wirelessly transmitting information. In particular, the beacon 200 can be configured to act as a GPS, transmitting position data of the first trailer and allowing a remote user to locate the trailer. The beacon 200 is particularly useful for a tractor driver extracting a trailer from a large number of trailers. For example, certain lots tend to store a large number of trailers that are not well organized or marked, requiring the driver to search to find a specific trailer. Typically, the driver's task is to look for the trailer by a specific identifier on the trailer (such as a license plate). This inefficiently requires the driver to individually view the license plate of each trailer on the lot to determine if it is the correct trailer. Additionally, it is difficult to accurately read the license plate from a distance, requiring the driver to approach each license plate within a reasonable distance or even to leave the tractor. Thus, the beacon 200 improves the manual search process by providing a GPS signal to an external network 118, which is ultimately received by the telecommunication module 116a in the tractor 102. Thus, the driver can use the beacon GPS signal to quickly and easily locate the trailer 104a within the lot. It is envisioned that the dashboard of the tractor 102 can not only display the position of the beacon 200 but also assist in indicating how to drive to the beacon 200. The beacon 200 can also include a distinct visual identifier, such as a flashing light of a designated color or a display showing an identifier, to warn the driver when approaching the correct trailer 104a. The beacon 200 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 correct trailer.

[0078] Still referring to Figure 1 , the dolly 106 and the second trailer 104b also include respective hubs 130c, 130d that are part of the VAN 101. 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 on the configuration, the hubs 130c, 130d can form a subnet or simply communicate with the first trailer hub 130b, which relays information to the tractor hub 130a. The second trailer 104b can include a telecommunication module, a beacon, and other hardware as needed.

[0079] Typically, transmitters / receivers 170a - 170d are located near the respective sensors, which can be pressure, temperature, speed, position, or other sensors. The transmitters / receivers 170a - 170d receive measurement data from one or more sensors and wirelessly report the data to the local hub. The transmitters / receivers 170a - 170d can also communicate using the 433 MHz band. In other cases, sensors 110a - 110d are directly wired to local hubs 130a - 130d, or directly wirelessly connected to local hubs 130a - 130d.

[0080] It is envisioned that subnets 112, 114 can be pre - established. In other words, for the trailer subnet, during assembly, a technician can use a pairing device 275 to pair sensors 110b, transmitter / receiver 170b, and hub 130b. As described above, the pairing can be highly automated and, to the extent needed, performed by the driver when connecting trailer 104a. Many sensors and such devices may be difficult to physically access, making pairing at installation advantageous. For example, sensors may be located on the vehicle's axle or within the vehicle's braking system. The driver's or technician's pairing device 275 may be able to read a code from the sensor, such as a QR code or NFC tag. The technician's pairing device 275 will be trusted by the VAN 101 (e.g., having password credentials for the network, etc.) and / or can be manually connected to the VAN 101, either wired or wirelessly. The pairing device 275 can then pair sensor 110b with hub 130b using the code from sensor 110b, thus connecting sensor 110b to subnet 114 and ultimately to the VAN 101.

[0081] Once the transmitters / receivers 170a - 170d are paired for wireless communication to the respective wireless hubs 130a - 130d, information can be transmitted across the VAN 101 from multiple devices. The data can be processed and provided to a central location in the vehicle 100, such as within the tractor 102, where the driver can see warnings or other feedback related to the readings of sensors 110a - 110d.

[0082] In some cases, one or more of the tractor 102 and trailers 104a, 104b may include third-party, on-vehicle telecommunication devices 116a, 116b. In the illustrated example, the tractor hub 130a communicates with the first telecommunication device 116a and the first trailer hub 130b communicates with the second telecommunication device 116b in the first trailer 104a. Each telecommunication device 116a, 116b sends data to a third-party source. In the given example, the data is transmitted to an external cloud platform where the data can then be obtained by external devices 120, such as computers, smart phones, etc. (e.g., paired device 275). The data can then be relied upon for fleet and asset management functions, such as checking the health of various components of the truck. In other cases, the telecommunication devices 116a, 116b can transmit to a medium other than the cloud network, such as a wide area network or directly to a third-party device.

[0083] Once the information from the VAN 101 is transmitted out of the vehicle 100 to the external network 118 and device 120, additional data review, analysis, and insights can be determined. The analysis and insights can then be sent back to the trailer 102 for the driver to view. A set of warning strategy functions can be generic or specific to particular needs. The algorithms that generate warnings are optimized through continuous data analysis. For example, vehicle behavior is characterized so that particularly identified parameters can be measured. Some parameters are tire pressure referenced to temperature, spare tire pressure, system temperature, system pressure, and gross vehicle weight (GVW). The external device 120 can have specific data, such as ranges or maximum allowable limits. Since the maintenance of these parameters is ongoing, if the GVW exceeds the limit or is out of range, or if the tires are under low pressure or unsafe to drive, a warning message can be sent to the driver for investigation and corrective action. As another example, a rapid pressure loss in a tire will issue a warning to the driver.

[0084] The subnets 112, 114 of the vehicle 100 are part of the broader VAN 101 and are in local communication, where one wireless gateway hub acts as an access point for the VAN 101. In some cases, the access point of the VAN 101 can change to a different gateway depending on the number of trailers 104 connected to the tractor 102 such that the access point is located at a central position of the vehicle 100. To centralize the access point, the tractor hub 130a searches down the length of the vehicle 100 for additional hubs 130 to determine the hub 130 that is located centrally. Since the hub 130 will be somewhere along the length of the vehicle 100, the VAN 101 can determine the hub location by a linear search rather than by searching a wide surrounding radius.

[0085] For example, if only a single trailer 104a is provided, the access point can be a wireless hub 130 at the center of one trailer, and all devices (e.g., transmitters / receivers, sensors, etc.) in trailer 104a or tractor 102 can reach the wireless hub 130 wirelessly. If a second trailer 104b is included, the access point can still be located at the center position of vehicle 100 within the first trailer 104a, or alternatively at a platform vehicle hub 130c that is also centered. If additional trailers (e.g., third and fourth trailers) are added, the access point can change to a new hub at the center position of vehicle 100, or multiple interconnected access points can be used to span a wireless signal across the entire length of vehicle 100. Alternatively, a full WiFi mesh system can be used to connect many hubs at positions across vehicle 100. Wireless hubs 130a - 130d that control central communication at each area of vehicle 100 allow many devices to communicate quickly and easily through VAN 101, even when devices within VAN 101 may be changed (e.g., sensor repair), or new or additional trailers and platform vehicles can be added to vehicle 100. In each case, each new device only needs to pair and connect to one wireless hub, and data from all devices can be shared across VAN 101. From the above, it should be understood that Figure 1 the exact number and arrangement of components shown in

[0086] Autonomous vehicle

[0087] As vehicles become autonomous, the subject technology will seamlessly integrate with an autonomous driving technology suite. For example, analysis of data from monitoring sensors can be used to control speed and even redirect an autonomous vehicle to a service station or rest stop for repair. Data analysis may also require the autonomous vehicle to enter an emergency mode, in which the vehicle may be pulled over for towing or control may be given to a remote operator.

[0088] In one embodiment, the tractor and trailer are combined into one. As expected, only the sensors of the trailer portion need to be initially integrated into the vehicle area network of the combined tractor - trailer. The combined tractor - trailer can still connect and carry additional trailers.

[0089] Wireless hub

[0090] As used herein, a microcontroller, computer, or intelligent device is one or more digital data processing devices. Such devices can typically be a personal computer, a computer workstation (e.g., Sun, HP), a laptop computer, a tablet computer, a server computer, a mainframe computer, a handheld device (e.g., a personal digital assistant, a palmtop computer, a cellular phone, etc.), an information appliance, a printed circuit board with components, or any other type of general-purpose or special-purpose, processor-controlled device, with or without an application-specific integrated circuit (ASIC), capable of receiving, processing, displaying, and / or transmitting digital data. A controller includes a random access memory (RAM), mechanisms and structures for performing input / output operations, a storage medium such as a magnetic hard disk drive, 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 a mouse.

[0091] The CPU is typically the logic circuitry that responds to and processes the instructions driving the controller and can include, but is not limited to, a central processing unit, an arithmetic logic unit, an application-specific integrated circuit, a task engine, and / or any combination, arrangement, or multiplicity thereof. Software or code generally refers to computer instructions that, when executed on one or more digital data processing devices, cause an interaction within the execution environment in the memory of the digital data processing device with operation parameters, sequence data / parameters, database entries, network connection parameters / data, variables, constants, software libraries, and / or any other elements required for the correct execution of the instructions.

[0092] A module is a functional aspect that can include software and / or hardware. Generally, a module contains the components required to complete a task. It is contemplated that the same hardware can implement multiple modules and portions of such hardware available for completing tasks. One of ordinary skill in the art will recognize that the software and various processes discussed herein are merely examples of the functions performed by the disclosed technology, and thus such processes and / or their equivalents can be implemented in various combinations in commercial embodiments without materially affecting the operation of the disclosed technology.

[0093] Now referring to Figure 2A , an exploded view of the wireless hub 130 is shown. Each hub 130a - 130d can be configured differently, but in Figure 2AAn exemplary hub 130 is shown. The wireless hub 130 includes a housing 131 having a removable cover 132 connected to form a protected interior 133. The housing 131 forms opposing recesses 134 for a compression limiter 135 to maintain the joint integrity of the plastic housing 131. The hub 130 includes a printed circuit board (PCB) 136 having the electronics required to create modules to perform the functions of the wireless hub 130, including data processing, storage, and transmission, such as a processor and memory (not explicitly shown).

[0094] The wireless hub 130 has an antenna (not explicitly shown) connected to the PCB 136 for wireless transmission. Additional antennas can be included as needed to allow the hub 130 to send and receive data with other devices described herein. For a wired connection, the hub 130 includes connection pins 138. The hub 130 can be powered by a battery and / or a wired connection. In one embodiment, the hub 130 is connected to a +12 / 24V power supply 144 (see Figure 2B ). The wireless hub 130 is configured to withstand large temperature variations in the range of -40°C to +85°C. The hub 130 is mounted on the outside of a tractor cab, such as on a chassis rail.

[0095] Now referring to Figure 2B , a schematic diagram of a microcontroller 140 suitable for use as part of the wireless hub 130 is shown. Generally, the microcontroller 140 is Figure 2A part of the PCB 136. The PCB 136 includes additional independent peripheral modules 141, 142, 143, 144, 145, and these can be incorporated into the microcontroller 140. The microcontroller 140 and modules 141, 142, 143, 144, 145 can include one or more standard off-the-shelf components, or be fabricated as one or more ASICs.

[0096] The hubs 130a - 130d can transmit and / or receive data between other hubs and / or range extenders 170a - 170d using a WiFi module 141 having a 2.4GHz band. The WiFi module 141 creates IP-based data communication that is transparent from the tractor to the trailer. A second 802.15.4 Thread network protocol communication module 142 can send and receive additional sensor content and range extension. A third communication module 143 can use sub-GHz (e.g., 433MHz band) as well as on-board decoding and polling functions for low-power modes. The third communication module 143 is particularly suitable for data from nearby sensors that are battery-powered and thus low-power.

[0097] The microcontroller 140 can also be connected to the CAN bus 145 for communication. The CAN bus 145 is typically located in the tractor 102. The microcontroller 140 can also be directly connected to another wireless hub 130 such that the hub 130 can be used as a radio frequency (RF) to CAN gateway. The PCB 136 also includes a 12 / 24V power supply 144 with surge protection to power the microcontroller 140 and other components and protect them from electrical damage.

[0098] When the microcontroller 140 is running, the hardware 147 creates a runtime environment (RTE) 146 such that the stored program is running (e.g., instructions are being executed). The hardware 147 includes a processor 148 coupled to a memory 149 and other components not explicitly shown. The program is stored in the memory 149 and accessed by the processor 148. The bootloader module 150 allows the memory 148 to be programmed. The operating system module 151 allows the user to interface with the hardware 147. The ECU abstraction layer module 152 facilitates unified access to the microcontroller functions performed by the peripherals and application programming interfaces (APIs). The MCAL microcontroller abstraction layer module 153 facilitates direct access to the devices on the PCB 136. The complex device driver module 154 includes various sub-modules 155a - 155c to implement the drivers for the communication devices 141, 142, 143 as needed. The bootloader module 150 can run the microcontroller 140 to program the memory 149 and write information.

[0099] It can be seen that the microcontroller 140 is specifically designed for the VAN 101. The microcontroller 140 also includes a power manager module 156 and a truck-to-trailer network link software module 157. The microcontroller 140 includes a TPMS module 158 and an on-vehicle weight motor vehicle unit module 159 to complete TPMS and MVU weight measurements in the VAN 101. The microcontroller 140 also includes an RF network management module 160 and a third-party software component module 161 to facilitate the use of RF network components and third-party software. Other modules may be present in the microcontroller 140 to implement any desired features in the VAN 101. Additionally, the microcontroller 140 features can be extended by making the hardware and software ready to host additional software and support other components (such as additional sensors, hubs, subnets).

[0100] Transmitter / Receiver

[0101] Now refer to Figure 3A and Figure 3B, respectively showing an exploded view and a schematic view of an exemplary transceiver / receiver 170. The transmitter / receiver 170 includes a housing 171 that forms a cavity 172, and the cavity 172 is sealed with a lid 173 to protect the printed circuit board (PCB) 174. Similarly, one or more compression limiters 175 are installed in the housing 171 to maintain the connection integrity of the plastic housing 171. The PCB 174 includes electronic devices that are used to perform all functions of the transmitter / receiver 170, including sending / receiving data, data processing, and storage. The PCB 174 may include a processor, a memory, an antenna, and other components (not explicitly shown).

[0102] For a wired connection, the transmitter / receiver 170 includes a connector 176. The transmitter / receiver 170 can be powered by a battery and / or from a wired connection. In one embodiment, the hub 130 is connected to a +12 / 24V power supply 183. The transmitter / receiver 170 is also configured to withstand large temperature variations in the range of -40°C to +85°C. Preferably, the transmitter / receiver 170 can be installed in any suitable location, but preferably outside the chassis rail.

[0103] Generally, most (if not all) functional modules are created by components of the PCB 174, but one or more peripheral components 181, 182, 184 can also be used. The PCB 174 can include one or more standard available components or be manufactured as one or more application-specific integrated circuits (ASICs). The components of the PCB 174 work together to form a central processing unit 180.

[0104] The transmitter / receiver 170 can use the 802.15.4 Thread network protocol communication module 181 to send and / or receive data to and from the hub and / or other transmitter / receivers 170 and to send and receive additional sensor content. Thus, the transmitter / receiver 170 can be used to expand the size of the VAN 101. The sensor communication module 182 uses sub-GHz (e.g., 433 MHz band) for low-power mode to effectively work with nearby sensors powered by batteries.

[0105] When the transmitter / receiver 170 is running, a runtime environment (RTE) 183 is created so that the stored program is running (e.g., instructions are being executed). The PCB 174 may include a processor coupled to a memory and other components not explicitly shown. The program is stored in the memory and accessed by the processor. One program is the operating system module 184, which typically allows a user to interface with the hardware 147 using a paired device 275.

[0106] The Hardware Abstraction Layer module 185 facilitates unified access to the extender function. The Vendor Software Development Kit (SDK) module 186 helps create applications with advanced features specific to the transmitter / receiver 170 and the Operating System module 184. The PCB 174 includes a Communication Stack module 187 for supporting the 802.15.4 Thread Network Protocol communication module 182.

[0107] It can be seen that the transmitter / receiver 170 is specifically designed for use in the VAN 101. The transmitter / receiver 170 includes a Power Manager module 188 and a Packet Forwarder module 189 for assisting in data conversion. The transmitter / receiver 170 also includes a Diagnostic and Debug module 190 that provides a user interface via the smart device 275 for startup and troubleshooting purposes. Other modules may be present in the transmitter / receiver 170 to implement any desired features in the VAN 101. Additionally, the transmitter / receiver 170 features can be extended by making the hardware and software ready to host additional software and support other components.

[0108] The transmitter / receiver 170 is particularly beneficial when retrofitting technology into existing trailers or tractors for future integration into the vehicle area network. The transmitter / receiver 170 can be connected, either wired or wirelessly, to various sensors and then pass the data to a wireless hub. In effect, the transmitter / receiver 170 is additional hardware to bridge the communication with existing hardware to new networked components.

[0109] Tire Pressure Monitoring System

[0110] In addition, the sensors can also be retrofitted. For example, see U.S. Patent Application No. 16 / 119,109, entitled "TIRE PRESSURE MONITOR WITH VARIABLE ANGLE MOUNTING," filed on August 31, 2018, which is incorporated herein by reference. In addition to the sensors indicating tire pressure, the sensors can be automatically positioned or programmed to indicate wheel position. Thus, when the VAN 101 identifies a pressure reading, the pressure reading is associated with a specific tire. The data associated with the tire can also include temperature data, which is also an indication of proper and improper performance.

[0111] It is contemplated that the smart device 275 can be used to assist in refilling tire pressure by reading pressure readings or other indicators such as honking / flashing lights on the smart device 275 to reduce the need for a tire pressure gauge to indicate that the pressure is within specifications. If the tire is equipped with an automatic tire filling function, the VAN 101 can trigger the refill and stop at the desired pressure. The sensor can also provide an indication that the lift axle has been lowered but the tire has not rotated. In this case, for example, in an autonomous vehicle, a tire lock warning can be generated and / or acted upon. Similarly, a tire blowout can be quickly detected after a blowout event to send a warning indicating the blowout and location. In an autonomous vehicle, a tire blowout warning results in safety and control responses. Preferably, the sensor is battery-powered with efficient power usage for long life.

[0112] Beacon

[0113] Now referring to Figure 4A and Figure 4B , a perspective view and a bottom exploded view of a beacon 200 in accordance with the present subject technology are shown. The beacon 200 can be mounted to the trailer 104a magnetically, with a bracket, or by any other fastener. The base plate 202 forms two grooves 204. Screws 206 hold magnets 208 in the grooves 204 such that the beacon 200 can be simply leaned against the trailer 104a for installation and easily removed without tools for wireless charging, repositioning, repair, etc. The base plate 202 has a marked arrow 210.

[0114] The beacon 200 also includes a rechargeable battery 212 for power. A printed circuit board (PCB) 214 has an LED 216 (shown in dashed lines) that emits light to display information such as the status of a trailer 104a (e.g., connected to the VAN 101 (e.g., constantly on) or being connected (e.g., flashing)). The PCB 214 also has components for wireless communication with the hubs 130a - 130d and / or the transmitters / receivers 170a - 170d. The PCB 214 is also equipped with an interface to a smart device 218 that can use near - field communication (NCF). The PCB 214 also has a GPS module 220 (shown in dashed lines) such that the VAN 101 can locate the beacon 200 and, in turn, locate the trailer 104a at a great distance, as described above. The beacon 200 also has a PCB top plate 222 for protecting the PCB 214. The PCB top plate 222 has a translucent window 224 aligned with the LED 216. A top cover 226 is coupled to the bottom plate 202 to seal the battery 212, the PCB 214, and the PCB top plate 222 within an oval housing 228. Preferably, the top cover 226, the bottom plate 202, the PCB 214, the PCB top plate 222, and the oval housing 228 have features 230 for screwing together. The PCB top plate 222 and the top cover 226 also have a plurality of aligned holes 232.

[0115] Multi - trailer Sorting

[0116] Now referring to Figure 5 , another exemplary vehicle area network (VAN) 301 for a tractor - trailer vehicle 300 is shown. The components and functions of the VAN 301 and the tractor - trailer vehicle 300 may be similar to those of the vehicle 100 and the VAN 101 described above, unless otherwise stated herein. Thus, like reference numerals in the "3" series represent similar components. For clarity, several components are not shown.

[0117] The vehicle 300 includes a tractor 302 having three trailers 304a - 304c and two platform trucks 306, all trailers including components related to Figure 1Those similar components discussed. VAN 301 allows communication between all components of vehicle 300, such as wireless hubs 330a - 330d, sensors 310a - 310f (such as TPMS, pressure sensors, temperature sensors, etc.), beacons 200, etc., as described above. Tractor 302 and each trailer 304a - 304c have corresponding subnets 314a - 314c within VAN 301, which connect components near the corresponding trailers 304a - 304c. Although not shown, it can be envisioned that VAN 301 includes a transmitter / receiver and other components required for robust performance. Each trailer 304a - 304c also includes a beacon 200 for assisting the driver in assembling vehicle 300.

[0118] It is advantageous to inform VAN 301 of the relative positions of trailers 304a - 304c and / or subnets 314a - 314c established on vehicle 300. VAN 301 with relative positions helps identify the positions of various sensors and other components, such as tires. In some cases, it may be a challenge for VAN 301 to identify the exact order of trailers 304a - 304c. Additionally, even if this is a manual calibration, trailers are often dropped, and new trailers are picked up and connected to the truck, requiring the new trailers to be sorted within VAN 301. Therefore, it is advantageous for VAN 301 to be able to automatically connect to a trailer, establish communication with the trailer, and determine the order of the trailers.

[0119] Now referring to Figure 6A - 6D , a flowchart 600 of a method for automatically identifying the order of three trailers 304a - 304c on vehicle 300 is shown. The method relies on data, including signal strength and time - of - flight (ToF), to continuously monitor and update the state of vehicle 300. The flowchart here illustrates the structure or logic of the present technology, which may be embodied in computer program software for execution by the hardware described here. Those skilled in the art will understand that the flowchart depicts the structure of computer program code elements, including the logic circuits on a printed circuit board having integrated circuits operating according to the present technology. Thus, the present technology can be practiced by machine components that present program code elements in the form of a sequence of functional steps corresponding to those shown in the flowchart, instructing a digital processing device (e.g., a microcontroller or a computer) to execute.

[0120] In step 602, the method starts with the microcontrollers of each of the hubs 330a - 330d being powered on and in normal operation to form the respective subnets 312, 314a - 314c. However, at this time, the trailer order is unknown and the trailers 304a - 304c can be arranged in any order. In step 604, each of the subnets 312, 314a - 314c monitors the received signal strength indicator (RSSI) and ToF data from all the other subnets 312, 314a - 314c. If there are no other hubs, the same data may come from a range extender or even directly from the sensors.

[0121] In steps 606 and 608, the tractor hub 330a identifies the trailer subnet 314a with the highest RSSI and the shortest ToF. The trailer subnet 314a with the highest RSSI and the shortest ToF should be the lead trailer 304a that is physically closest to the tractor 302. In step 610, the tractor hub 330a compares the subnet 314a identified as having the highest RSSI with the subnet 314a having the shortest ToF. If the subnets in steps 606 and 608 do not match, i.e., the subnet with the highest RSSI is different from the subnet with the shortest ToF, the method restarts at step 602. In step 612, if the two subnets 314a match, the subnet 314a is identified as being on the first trailer 314a (e.g., the lead trailer). Additionally, if in step 610, there are only RSSI and ToF from the same subnet 314a, the tractor subnet 312 can identify the associated trailer 304a as the only trailer present.

[0122] After successfully identifying the lead trailer 304a, in steps 614 and 616, the lead trailer wireless hub 330b identifies the subnet 314b with the highest RSSI and the shortest ToF, excluding the tractor subnet 312 in both cases. In step 618, if there is a match, the corresponding subnet 314b is identified as the second trailer 304b following the lead trailer 304a in step 620, as Figure 6B shown. If there is no match in step 618, the method restarts at step 602. In another embodiment, the method restarts at step 612 by using the previously established lead trailer identification. If in steps 614 and 616, there are only RSSI and ToF from the two subnets 314a, 314b, the tractor subnet 312 can identify and order the two associated trailers 304a, 304b. In one embodiment, the process ends after a successful identification in step 620.

[0123] Once the second trailer 304b is identified, any one of the hubs 330a, 330b, or the trailer wireless hub 330c of the second trailer 304b can identify the third trailer 304c. For this purpose, the trailer wireless hub 330c is used in the following description. At steps 622 and 624, the hub 330c identifies the subnet 314c with the highest RSSI and the shortest ToF, excluding the tractor subnet 312 and the lead trailer subnet 314a in both cases. At step 626, if there is a match, it is assumed that the identified subnet 314c corresponds to the third trailer 304c (i.e., the trailer 304c immediately following the second trailer 304b). At step 628, the third trailer 304c is identified based on the third trailer subnet 314c, as Figure 6B shown. If there is no match at step 626, the entire process restarts at step 602, but it can also return to step 620.

[0124] As will be understood by those skilled in the art, the steps of identifying the next trailer in the trailer line can be repeated for additional trailers. Assuming the vehicle 300 has three trailers 304a - 304c, as Figure 5 in the example of, then at step 630 the first result of sorting the three trailers 304a - 304c is determined, which indicates the initial order of all the trailers 304a - 304c. If at steps 622 and 624 there are only the RSSI and ToF from the three subnets 314a - 314c, the tractor subnet 312 can identify and sort the associated three trailers 304a, 304b and end the method or perform a double - check as follows. For more trailers, the method can continue.

[0125] After the double - check step 630, the process of determining the order of the trailers 304a - 304c then repeats essentially in reverse order to obtain a second set of results for comparison to determine whether the initial sorting is accurate. More specifically, now referring to Figure 6C , the method continues to monitor the RSSI and ToF data from all other subnets 314a - 314c at step 632. At steps 634 and 636, starting from the identified third trailer 304c, the third trailer subnet 314c identifies the subnet 314b with the highest RSSI and the shortest ToF by comparing the data from all the identified subnets 312, 314a - 314b. At step 638, the subnets with the highest RSSI and the shortest ToF are compared. If the identified subnets with the highest RSSI and the shortest ToF are different, the method restarts at step 632, but if there is a match, it is determined that the identified subnet 314b corresponds to the second trailer 304b. At step 640, the identification of the position of the second trailer 304b is saved as part of the second set of results.

[0126] In steps 642 and 644, the newly identified second trailer subnet 314b then identifies the highest RSSI and shortest ToF in both cases, excluding the third trailer subnet. In step 646, the second trailer subnet 314b compares the identified subnets against each criterion, typically subnet 314a. If there is a match, then in step 648 it is determined that the identified subnet (e.g., subnet 314a) corresponds to the lead trailer 304a and is saved as part of the second set of results. If the subnets identified in step 646 are different, the method restarts at step 632.

[0127] Now referring Figure 6D , in both cases of steps 650 and 652, the identified lead trailer subnet 314a then identifies the subnet with the highest RSSI and shortest ToF, excluding the second and third trailer subnets 314b - 314c. In step 654, the lead trailer subnet 314a compares the identified subnets. If there is a match, correctly the tow vehicle subnet 312, then the method proceeds to step 640, in which it is determined that the identified tow vehicle subnet 312 corresponds to the tow vehicle 302. The method collects and saves information related to the three appropriately located subnets 312, 314a - 314b as part of the second set of results.

[0128] In step 660, the subnets 312, 314a - 314b are identified and sorted a second time, and then the first and second sets of results are compared. If the order determined in the first set of results is consistent with the order determined in the second set of results, then it is verified that the order of the VAN subnets 312, 314a - 314c has been correctly determined and the method ends at step 662. Otherwise, if the orders determined in the first and second sets of results are different, then the method restarts at step 602 so that a verified order can be determined.

[0129] In this way, the VAN 301 is able to automatically determine the order of the trailers 304a - 304c based on the order of the subnets 330b - 330d without input from the user. The order of the trailers 304a - 304c can then be relied upon to determine where the various sensors are located and to easily take action based on sensor readings and / or warnings. For example, if a tire pressure monitoring sensor reports data triggering a low pressure warning, it is advantageous for the user to be able to narrow down the potential tires corresponding to that warning. The subnet of a given sensor can be used to determine the trailer (or tow vehicle) to which the sensor belongs, based on the order of the trailers, without additional user input. Thus, if the pressure sensor reporting the warning is in the third trailer subnet 314c, the user can be alerted that the tire pressure of the third trailer 304c is low. This avoids the need for the user to spend time checking the tires of the tow vehicle 302 or the other trailers 304a - 304b. This can similarly be used for readings and warnings of other known sensors in the art.

[0130] It is also contemplated that the dolly 306 may have wireless hubs that each form a separate subnet rather than being part of the trailer subnets 314b-314c. In this case, the dolly subnets would be similarly identified and sorted in the method of sorting subnets. The process described herein may use shared specifications for standardized information. The shared specifications allow the process of connecting trailers to the VAN 101, 301 and sorting trailers to be easily performed across multiple truck and trailer brands. Preferably, no auxiliary user action is required to determine the sorting of the trailers 104, 304. For example, when electrical and / or pneumatic connections are made between the tractor 102, 302 and the trailers 104, 304 and between the trailers 104, 304, the method for sorting the trailers 104, 304 may be initiated. The method may also be triggered by using a smart device 275.

[0131] Reference now Figure 7A - 20E , showing various actuator and sensor arrangements. As described above, the sensor arrangement may be incorporated into Figure 1 VAN 101. References Figure 7A and 7B , a sensor arrangement 700 is shown. The sensor arrangement 700 includes a fixed sensor portion 702 and a mobile target portion 704. The portions 702, 704 are mounted to a brake assembly, wherein the sensor portion 702 is fixed to a casting or other fixed feature, and the target portion 704 is mounted on a mobile feature. Therefore, as brake wear occurs and the brake is engaged, the target portion 704 moves relative to the sensor portion 702 in proportion to the brake wear, and then, the signal from the sensor portion 702 changes to indicate wear. The sensor arrangement 700 can be installed in a preset casting position, retrofit an existing assembly, be manufactured integrally with the brake assembly, and combinations thereof. Typically, the sensor arrangement 700 is not integrated with a consumable portion, so that by being battery powered, the sensor arrangement 700 can perform measurements after many other consumable parts (e.g., brake pads) have been replaced multiple times. It is conceivable that the sensor arrangement 700 may require calibration during component replacement.

[0132] Typically, the range of motion of target portion 704 is limited, requiring calibration and correct positioning so that leading edge 706 of target portion 704 is aligned with travel start line 708 without wear. As maximum brake wear approaches, leading edge 706 is approximately aligned with the end of travel line 710 or less.

[0133] Reference now Figure 8A - 8C, shows a floating caliper brake system 800 having a sensor assembly 820. The brake system 800 is located at each end 870 of an axle 872. When braking is applied, the floating caliper 802 moves linearly relative to the fixed bracket 806 in a direction parallel to the movement arrow 804 to force brake pads against a wheel (not clearly shown). The sensor assembly 820 (shown separately in Figure 8C includes a fixed sensing element 822 and a movably mounted target portion 824. The target portion 824 includes a magnet 826, and the sensing element 822 includes an anisotropic magnetoresistive (AMR) sensor on a printed circuit board (PCB) 828 that detects a magnetic field based on the positioning of the magnet 826.

[0134] In the example given, the sensing element 822 is attached to the bracket 806 and the target 824 is attached to the floating caliper 802. When braking is applied, the floating caliper 802 moves and the positioned target 824 moves parallel to the fixed sensing element 822 such that the target 824 changes position and / or angle relative to the sensing element 822. The movement of the target 824 is measured by the sensing element 822 and reported to a subnet, wireless hub, and / or VAN.

[0135] Then the brake pad thickness and / or wear can be determined based on the measured movement and the range of movement between the floating caliper 802 and the bracket 806. Measurements from sensors on the vehicle can be matched to corresponding locations on the vehicle to determine the brake pad thickness at different locations. The brake pad thickness can be analyzed within the VAN to calculate the remaining brake pad thickness and compare that thickness to regulatory allowances.

[0136] If the thickness of the brake pad is below an acceptable level, a warning will be generated in the tractor to the driver, thus identifying the specific brake pad that needs to be replaced. Additionally, data from one or more sensors can be used to verify new brake pads based on the initial offset measured when the brake is applied, or for wheel-to-wheel comparison. For example, excessive wear on a single wheel may indicate a caliper sticking, so a maintenance inspection can be scheduled. Measurements can be stored and analyzed to determine the wear rate and the overall slope of brake pad wear over time. Based on the data, maintenance reminders and scheduling are done automatically. Changes in the wear rate or slope can indicate a fault condition in the actuator, related to driver behavior, or attributable to a change in the primary driving conditions, and corresponding warnings can be issued to the driver and / or fleet manager. The positioning of the sensing element 822 and the target portion 824 can also be reversed, where the sensing element 822 is attached to the floating caliper 802 and the target portion 824 is attached to the bracket 806.

[0137] Now referring to Figure 9A - 9C , shows another brake system 900 having a sensor assembly 920. The brake system 900 is in Figure 9Ais shown on the shaft 972 therein. The braking system 900 is a fixed caliper braking system, wherein the brake pads 902 move relative to Figure 9B the fixed caliper 906 shown in more detail and isolated therein. Thus, the sensing element 922 can be attached to the fixed caliper 906, while the target portion 924 is attached to the brake pad 902 or the support structure surrounding the brake pad to linearly move as the brake pad 902 moves. Alternatively, the sensing element 922 can be attached to the brake pad 902 and the target portion 924 is attached to the fixed caliper 906. Again, the signal from the sensing element 922 can be wirelessly transmitted. Further, the braking system 900 is separate from the consumable components and the power supply battery, such that the braking system 900 can last for the life of the vehicle except for possible recalibration. The calibration of the braking system 900 is preferably performed automatically or by using a smart device communicating with the vehicle local area network.

[0138] Now refer to Figure 10A - 10E , Figure 10A is a perspective semi-exploded view of a disc braking system 1000 according to the present subject technology. Figure 10B is a different perspective semi-exploded view of the disc braking system 1000. Figure 10C - 10E is a detailed view of the brake sensor assembly 1020.

[0139] The disc braking system 1000 includes a fixed mounting plate 1002. Preferably, the sensor element 1022 can be mounted to an attachment plate 1012 (see Figure 10C ), which attachment plate 1012 can in turn be attached to the fixed mounting plate 1002 at location 1003. The target portion 1024 is mounted on the floating portion of the caliper 1110 so as to move with the brake pads as the brake pads wear during the braking process. The preferred location for mounting the target portion 1024 is the circular protrusion 1006. As Figure 10C is visible, the sensing element 1022 and the target portion 1024 can be retrofitted by using brackets 1023, 1025 respectively. Alternatively, in Figure 10D , the target element 1024 is integrated into the casting 1027. For example, the casting 1027 is part of the circular protrusion 1006.

[0140] Now refer to Figure 11 - Figure 20E , other braking systems and brake sensor assemblies are shown. The systems and sensor assemblies can operate as described above with respect to the systems and sensor assemblies unless otherwise specified herein. In particular, Figure 11 - Figure 20E the braking system in is a drum braking system, and all the sensor assemblies shown therein are configured to be used with the drum braking system as described below.

[0141] Now refer to Figure 11 - Figure 13, a vehicle (not shown) includes an axle 1202 having a braking system 1200 at each end 1204. When braking is applied by a command in a driver or autonomous vehicle, an air brake chamber 1212 actuates a push arm or push rod 1208 along the movement arrow 1209. The movement of the push rod 1208 causes a camshaft 1210 that controls the movement of brake pads to rotate.

[0142] Specifically referring to Figure 12 and Figure 13 , an exemplary sensor assembly 1320 is shown separately on the drum braking system 1200. The sensor assembly 1320 includes a sensing element 1322 and a target portion 1324, which may be similar to other sensors described herein. When the brake is applied, the air brake chamber 1212 of the brake actuates the push rod 1208. A fixed brake chamber bracket 1216 is attached to the brake chamber 1212, and the push rod 1208 extends through a hole 1218 in the brake chamber bracket 1216. The sensing element 1322 is attached to the chamber bracket 1216, while the target portion 1324 is attached to the push rod 1208. When the brake is applied, the push rod 1208 moves, changing the position of the target portion 1324 relative to the sensing element 1322. These relative positions are measured and can be used to first calculate the chamber stroke and ultimately calculate brake pad wear through an algorithm that correlates the stroke of the brake chamber 1216 through the geometry of the slack adjuster, camshaft / cam, and cam follower. The measurement data from the sensor assembly 1320 can then be used as described for other sensors herein.

[0143] Now referring to Figure 14 and Figure 15 , an exemplary sensor assembly 1520 for a drum braking system 1400 is shown separately on the braking system 1400. The sensor assembly 1520 includes a sensing element 1522 and an arcuate target element 1524, which may be similar to other sensors described herein. The braking system 1400 includes a push rod 1408 that moves parallel to the movement arrow 1409. The push rod 1408 is connected to a slack adjuster head assembly 1430 such that when the push rod 1408 moves, the slack adjuster head assembly 1430 rotates as shown by the movement arrow 1431. The target portion 1524 is mounted on the slack adjuster head assembly 1430 for rotational movement therewith. The braking system 1400 also includes a fixed mounting plate 1420, where the sensing element 1522 is coupled to the fixed mounting plate 1420.

[0144] When the brake is applied, the pushrod movement 1409 causes a rotational movement 1431 of the slack adjuster head assembly 1430, which in turn causes a similar movement of the target portion 1524. The sensing element 1522 does not move. Thus, when the brake is actuated, the position of the target portion 1524 relative to the sensing element 1522 changes. These relative positions are measured and can be used to calculate brake pad wear through an algorithm, as described herein. The measurement data from the sensor assembly 1520 can then be used as described for the other sensors described herein.

[0145] Now referring Figure 16 and 17 , another drum brake system 1600 and an exemplary sensor assembly 1720 are shown. The sensor assembly 1720 includes a sensing element 1722 and a target portion 1724, which can be similar to other sensors described herein. The drum brake system 1600 is also similar to the brake system 1200 described above. The drum brake system 1600 includes an adapter plate 1626 coupled to an adjusting arm 1630. The adapter plate 1626 facilitates coupling the sensing element 1722 in a fixed position. The target portion 1724 is attached to the adjacent moving adjusting arm 1630. Alternatively, the adapter plate 1626 can carry the target portion 1724 and the sensing element 1722 can be attached to the adjusting arm 1630. In either case, the adapter plate 1626 illustrates a possible retrofit application.

[0146] When the brake is applied, the pushrod movement 1609 again causes a rotational movement 1631 of the slack adjusting arm 1630. In the example given, the target portion 1724 is attached to the moving adjusting arm 1630 and the sensing element 1722 is fixed to the stationary adapter plate 1626. Thus, when the brake is applied, the position of the target portion 1724 relative to the sensing element 1722 changes. These relative positions are measured and can be used to calculate brake pad wear through an algorithm as described herein. The measurement data from the sensor can then be used as described for the other sensors described herein.

[0147] Now referring Figure 18 and Figure 19 , yet another drum brake system 1800 with an exemplary sensor assembly 1920 is shown. The sensor assembly 1920 includes a sensing element 1922 and a target portion 1924, which can be similar to other sensors described herein. The drum brake system 1800 is also similar to the drum brake system 1200. The drum brake system 1800 includes an indicator plate 1840 coupled to a camshaft 1850.

[0148] When the brake is actuated, the camshaft 1850 rotates along arrow 1851 to bring the brake pads into contact with the drum. The target portion 1924 is attached to the indicator plate 1840, which does not move in response to the application of the brake pads. However, the sensing element 1922 is attached to the adjusting arm 1830, which moves when the camshaft 1850 rotates. Thus, when the brake is activated, the position of the target portion 1924 relative to the sensing element 1922 changes. These relative positions are measured and can be used to calculate brake pad wear through an algorithm similar to the algorithms described herein. Then the measurement data from the sensor can be used as described for the other sensors described herein.

[0149] Now referring Figure 20A , an end of a drum brake system 1950 generally adjacent to a wheel is shown. The drum brake system 1950 can include other components of a drum brake system as described herein and can be incorporated as part of any other drum brake system described herein. As described above, when the brake is applied, actuation of the push rod is translated into rotation of the camshaft (e.g., Figure 11 rotation of shaft 1210 in

[0150] Now referring Figure 20B , a comparison shows the positioning of the S-shaped cam 1950 in the case where the brake is disengaged in image 1960 and the brake is engaged in image 1962. It can be seen that when the brake is disengaged, the cam followers 1964 are separated by a first distance D1. When the brake is engaged, the cam followers 1964 slide along the rotating S-shaped cam 1955 and reach a final separation distance D2 when the brake is fully engaged. To show the rotational movement of the S-shaped cam 1952, in the example showing brake engagement 1962, a phantom of the S-shaped cam 1968 in its original disengaged position and the brake in the disengaged state is shown as a dashed line superimposed on the final S-shaped cam 1952 position. In the engagement position in the example shown, the S-shaped cam 1952 rotates approximately 14 degrees between the disengaged and engaged positions of images 1960, 1962. As the brake pads wear, a greater total rotation is required to fully engage the brake.

[0151] Now referring Figure 20C - Figure 20E, shows an example of the typical positions of the S-cam and cam follower during the service life of the brake. In particular, Figure 20C represents the positioning of the S-cam and cam follower of a new brake, Figure 20D represents the positioning of the S-cam and cam follower of a brake near the middle of the brake life cycle, while Figure 20E represents the positioning of the S-cam and cam follower of a brake near the end of the brake life. In each Figure 20C - Figure 20E , the S-cam 1970 and cam follower 1972 in dashed lines represent the positioning of the disengaged brake system, while the S-cam 1974 and cam follower 1976 represent the positioning of the engaged brake system. The slack adjuster of the brake system includes a regulator mechanism that automatically compensates for brake pad wear by adjusting the position of the S-cam 1970 throughout the service life of the brake. In the example given, the slack adjuster attempts to maintain the positioning of the S-cam 1970 such that the S-cam 1970 undergoes approximately 14 degrees of rotation between the disengaged S-cam 1970 and the engaged cam 1974. As the brake pads wear, the rotation required to fully engage the brake increases. It can be seen that the positioning of the S-cams 1970, 1974 changes with wear such that the intervals D1, D2, D3 between the cams 1972, 1976 increase with increasing wear, with D3 > D2 > D1. Through this process, when the brake is applied, the relative arcuate portions 1975, 1977 of the S-cams 1970, 1974 continue to interact with the cam followers 1972, 1976.

[0152] Now refer to Figure 20F , which shows a graph 1978 of cam follower displacement during various S-cam rotations. The concentric circles 1980 are zeroed at the center of the graph 1978 and represent an increase in displacement in millimeters between the opposing cam followers as the concentric circles 1980 approach the perimeter of the graph 1978. The circular perimeter 1982 represents the displacement distance of the S-cam 1979. The plotting points 1984 represent the displacement of the cam follower at 10-degree S-cam angle increments. For ease of explanation, the values of the cam follower displacement at each S-cam angle plotted are subsequently consolidated in a table 1986.

[0153] Now refer to Figure 20G, Table 1986 is plotted in a typical line graph format in Figure 1989. The x-axis represents the rotational angle of the S-cam in degrees, while the y-axis represents the displacement distance between the cam followers in mm. The plotting points 1988 are the values shown in Table 1986, and they are also the plotting points 1984 of Figure 1978. Then a trend line 1990 can be formed between the plotting points 1984. The equation 1992 of the trend line 1990 can be calculated. At any given point in the brake life, the brake pad thickness can be calculated using the difference between the current cam follower spacing and the initial cam follower spacing when the brake was new. This is done according to the following equation:

[0154] Thickness = t i -m(θ n -θ i ) Equation 1

[0155] In Equation 1, Thickness is the currently calculated brake thickness to be determined, t i is the initial brake pad thickness, m is the slope of the trend line 1990, θ n is the current S-cam angle, and θ i is the initial S-cam angle. For example, if the initial S-cam angle of the braking system is 0 degrees and the initial brake pad thickness is 22 mm, and assuming Figure 20G the slope of the curve calculated in is 0.1861, Equation 1 for a current S-cam angle of 100 degrees will yield the following result: Thickness = 22 mm - 0.1861(100 - 0) = 3.39 mm. Thus, when the S-cam rotates through an angle of 100 degrees, the current brake pad thickness is determined to be 3.39 mm. This process can be repeated at different S-cam angles during the brake life in order to determine the time to replace the brake pads before brake failure. It should be noted that during similar braking states (i.e., separation or engagement), the initial and current S-cam angles and the cam follower displacements should be compared. Generally, this process can be used as an algorithm related to the braking system described herein and for calculating brake pad wear. Thus, various sensors can be employed to collect data related to the rotational position of the S-cam, including any of the other position sensors described herein.

[0156] Based on the above thickness calculation, corresponding warnings or messages can be displayed to the user indicating the current brake pad thickness, wear, and / or possible mileage until failure or alternatively the possible degree of maintenance wear and brake pad failure based on the mileage driven to reach the current wear level. For example, assume that the brake pads have worn from 20 millimeters to 10 millimeters in thickness over the first 100,000 miles of driving, and brake pad failure is assumed to occur at 5 millimeters. The braking system can include an algorithm to interpolate between the initial brake pad thickness of 20 millimeters and the expected failure thickness of 5 millimeters to determine that the brake pads are likely to reach 5 millimeters and thus fail within an additional 50,000 miles. The remaining mileage until expected brake pad failure can be continuously displayed to the user, or the system can be configured to automatically generate a display warning or alert a certain number of miles before the expected failure point. The system can also consider more advanced driving variables such as the impact of city versus highway driving, vehicle load, or other variables that may cause uneven wear. The system can also aggregate and compare data from all braking sensors, comparing brake pad wear across all wheels to identify outliers that may indicate anomalies and warning the user of potential wheel failures. For example, a dragging brake may cause the brake pads to wear faster compared to other brakes.

[0157] The information from the above sensors can be used in various contexts. For scheduling purposes, maintenance planners can rely on this information. If the vehicle typically travels long routes, brake pad replacements can be planned based on the expected mileage before or during long trips until the brake pads fail. The information can also be provided to fleet operators as one of a large set of metrics related to the road readiness of the trailers. If the brake pads are likely to fail at some point during the expected truck route, the indicator can alert the fleet operator of this fact so that maintenance can be performed in advance.

[0158] It should be understood that all sensors described herein are configured to be used in a VAN and as part of the system described herein. In other embodiments, the sensor assembly can utilize other non-contact techniques to determine distance, such as optical devices, capacitive sensors, inductive sensors, sonar, radar, etc. Anisotropic magnetoresistance (AMR) and tunneling magnetoresistance (TMR) are also particularly suitable for the subject technology because these methods consume very little power in a battery-based sensor assembly.

[0159] It can be seen that the subject technology can initially be integrated into the braking structure or retrofitted. In either case, the braking sensors are preferably non-consumable. The braking sensors may have sufficient battery life to last the lifespan of the vehicle.

[0160] Now refer to Figure 21, shows a schematic diagram of a vehicle area network (VAN) 2101 with an integrated brake sensor assembly 2110. VAN 2101 is similar to that described above with respect to Figure 1 and the similar numbers in the "2000s" are used to refer to similar components, and not all components will be described in detail again. Each of the brake sensor assemblies 2110 is coupled to a wheel 2111. VAN 2101 communicates with a data repository 2121. The data repository 2121 can be integrated with the tractor 2102 and / or at an external remote device (e.g., a server) as shown, and the VAN can communicate with it via a remote communication device or the like.

[0161] As described above, the sensors 2110 can continue to be used after the brake pads are replaced. However, during initial installation or when replacing brake pads, the sensors 2110 typically need to be calibrated. Calibration establishes a baseline for all subsequent measurements and thereby determines the remaining brake pad thickness. In one embodiment, the sensors 2110 are capable of measuring a total span of 25 mm. In this span, the friction brake pad thickness is approximately 18 to 20 mm. With new brake pads, the sensors 2110 are "zeroed" so that the relative movement indicating wear can be subtracted from the brake pad thickness to yield the remaining thickness by the repository 2121. The absolute position of the target element can be measured, but the relative position will be calculated and recorded. Preferably, when new brake pads are installed or during initial commissioning, the reading of the sensors 2110 is close to the zero absolute position to allow for the most useful measurement range during the life of the brake pad wear. For example, if the data repository 2121 determines that the sensor absolute position is not within a predetermined tolerance for new brake pads, the data repository can generate an out-of-tolerance "zero" point indicating a problem, e.g., the sensor is incorrectly installed or the thickness of the brake pad installation is less than the thickness for a full service life.

[0162] When the data repository 2121 receives information from the sensors 2110, the data repository 2121 improves the utilization, performance, and safety of the vehicle. For example, the data repository 2121 can determine a minimum brake pad thickness for comparison with a predetermined threshold. Since brake pad wear is typically gradual, a warning can be provided to schedule a replacement. The service team can pre-program the warning and the level of the warning to avoid violating any legal or manufacturer-recommended minimum standards. In one embodiment, the tractor dashboard can display a "remaining mileage" indicator before the brake pads need to be replaced, which is based on the brake pad wear rate captured over a period of time at a specific distance. The "remaining mileage" indicator can also be sent to one or more smart devices (e.g., a desktop computer, a smartphone, etc.). The data repository 2121 aggregates all the brake sensors 2110 to compare the performance of each brake with the performance of the other brakes. Thus, abnormal wear can be determined to detect potential problems, such as brake drag or uneven wear of force difference, faster than other methods.

[0163] The data repository 2121 may also include information about the types of routes typically covered by a particular vehicle or company. For example, a 20-mile trip each time may not require the same "service mileage" warnings and alerts as a 1500-mile trip. For long trips, mid-trip services can even be scheduled into the delivery schedule. Although the sensor readings are real-time or near real-time, the measurements can be provided periodically to conserve the sensor battery life. With such continuous monitoring, the data repository 2121 can advantageously use statistical modeling and use averages to minimize nuisance warnings from errors. The continuous data stream allows for an actual status check prior to any trip, which is more than just a visual inspection.

[0164] In addition, brake wear can be a high-level insight into driver behavior. Given the brake pad pressure load or the degree of braking applied, the brake pad compression can be anticipated (e.g., the brake pads are expected to compress to different degrees if the user taps the brakes compared to if the user slams on the brakes to make an emergency stop). It is noted that this requires some input data on the degree to which the brakes are applied during one or more braking events. Then the second sensor reading can be compared with the 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 of past known deviations for that particular vehicle or multiple vehicles.

[0165] The sensor 2110 may also include a temperature sensor. The temperature sensor can be inside the brake pad wear sensor and / or inside a separate probe connected to or near the brake wear sensor. The temperature probe can be connected to the brake wear sensor so that temperature data can be combined with the braking data for transmission. Then the data can be transmitted to the range extender 2170 and ultimately to the data repository 2121 and / or the tractor 2101 for display or generation of control commands in an autonomous vehicle.

[0166] Temperature data is particularly useful for brakes because brakes generate a large amount of heat during normal operation and even more during heavy-duty operation (e.g., when going down a steep hill fully loaded). Since brake pads lose some braking force (coefficient of friction) as the temperature increases, the driver can be warned to use the engine to slow down the vehicle, or an autonomous vehicle can make a similar adjustment. If the temperature gets too high, the brake pads can also glaze over and permanently reduce performance. Additionally, the heat generated by the brakes can damage nearby components (e.g., ABS components), or in more severe cases, cause a wheel-end fire. By continuously monitoring the temperature, warnings and appropriate actions can be taken to avoid a reduction in braking potential, which can lead to a longer required stopping distance. Further, the data repository 2121 can generate warnings and / or changes to drive control settings to avoid permanent damage to the brake pads and potentially the rotors due to excessive temperature. In the most extreme cases, the data repository 2121 can warn of temperatures that may soon lead to a wheel-end fire due to grease / oil or even tire fires. In some cases, the temperature sensor can also include an ambient temperature sensor so that the temperature sensor readings of the braking system can be normalized for ambient driving conditions.

[0167] Figure 22A is an exemplary graph 2000 of the Celsius temperature measured by the brake pad temperature sensor during an accumulated driving time period. When a significant peak in the brake pad temperature occurs, as shown in block 2202, a processor such as a wireless hub within the vehicle can perform anomaly detection correlation modeling, as Figure 22B shown.

[0168] Now referring to Figure 22B , the anomaly detection correlation modeling graph compares the temperature measured by the brake pad temperature sensor represented by plot line 2206 with the wheel-end temperature tracked by the wheel-end temperature sensor at the corresponding wheel represented by plot line 2208. If there is a significant difference in plot lines 2206, 2208 that can indicate an anomaly, a warning can be provided to indicate a potential failure condition of the brake pads at the corresponding wheel. Additionally or alternatively, the peaks in the brake pad temperature can be compared between different wheels, and a significant difference also indicates a failure condition, as described above.

[0169] All orientations and arrangements of the components shown herein are for illustrative purposes only. Additionally, those of ordinary skill in the relevant art will understand that in alternative embodiments, the functions of several elements can be performed by fewer elements or a single element. Similarly, in some embodiments, any functional element can perform fewer or different operations than those described with respect to the illustrated embodiments. Further, functional elements shown as distinct for purposes of illustration can be incorporated into other functional elements in a particular implementation.

[0170] Although the subject technology has been described with respect to preferred embodiments, those skilled in the art will readily appreciate that various changes and / or modifications can be made to the subject technology without departing from the spirit or scope of the subject technology. For example, each claim may depend in a multiple dependent manner from any or all of the claims, even if such claims were not initially claimed.

Claims

1. A system for measuring braking data from a drum brake assembly of a vehicle, the drum brake assembly including a brake chamber that actuates a push rod when the vehicle brake is applied, actuation of the push rod causing rotational movement of an adjusting arm and a connected slack adjuster head around a camshaft, the system comprising: A brake sensor mounted to the drum brake assembly and configured to measure braking data, the braking data including displacement of the drum brake assembly during braking, the brake sensor configured to transmit the braking data via a wireless vehicle area network; wherein the drum brake assembly is configured to rotate an S-shaped cam when the brake is applied such that the S-shaped cam engages two cam followers, the two cam followers being coupled to opposing brake shoes; and wherein the displacement of the drum brake assembly represents the difference in displacement distance between the two cam followers when the drum brake assembly is in a disengaged state and when the drum brake assembly is in an engaged state.

2. The system according to claim 1, wherein The brake sensor includes a sensing element and a target, the sensing element being configured to sense a magnetic field of the target.

3. The system according to claim 2, wherein: The sensing element is connected to a fixed brake chamber bracket that remains in a fixed position relative to the vehicle when the vehicle brake is applied; and The target is connected to the push rod and is configured to move relative to the sensing element when the vehicle brake is applied.

4. The system according to claim 2, wherein: The sensing element is connected to a fixed mounting plate adjacent to the slack adjuster head that remains in a fixed position relative to the vehicle when the vehicle brake is applied; and The target is connected to the slack adjuster head and is configured to move relative to the sensing element when the vehicle brake is applied.

5. The system according to claim 2, wherein: The target is connected to a fixed indicator plate adjacent to the camshaft that remains in a fixed position relative to the vehicle when the vehicle brake is applied; and The sensing element is connected to the adjusting arm such that the sensing element moves as the adjusting arm and camshaft rotate when the vehicle brake is applied.

6. The system according to claim 1, wherein The system is configured to measure an S-shaped cam rotation angle, and the difference in displacement distance between the two cam followers is calculated based on the S-shaped cam rotation angle.

7. The system according to claim 6, wherein, The system is configured to determine a current brake pad thickness by: Calibrate the drum brake assembly at an initial brake pad thickness t i and an initial S-cam rotation angle θ i ; Determining a curve slope of cam follower displacement versus S-shaped cam rotation angle m; and Measure the current S-cam rotation angle θ n ; And The current brake pad thickness is calculated by setting the current brake pad thickness equal to: t i -m(θ n -θ i ).

8. The system according to claim 7, wherein, The system is configured to provide a warning based on an expected brake pad failure thickness.

9. The system according to claim 7, wherein, The system is configured to provide an indicator of one or more of: a distance before maintenance of the drum brake assembly is recommended; or a distance before failure of the drum brake assembly is expected.

10. A sensing system for measuring braking data from a drum brake assembly having a push rod configured to cause an S-cam to rotate about a cam shaft in response to the application of a braking force to engage two cam followers associated with opposing brake shoes, the sensing system comprising: A sensing element; And A target, wherein the sensing element and the target are configured to move relative to each other in response to the rotational movement, and wherein the sensing system is configured to determine 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 based on the relative movement of the sensing element and the target.

11. The sensing system according to claim 10, wherein: The target is a magnet that generates a magnetic field; and The sensing element is an anisotropic magnetoresistive sensor configured to sense the magnetic field of the magnet to generate a signal.

12. The sensing system according to claim 10, wherein: The sensing element is configured to be connected to a fixed brake chamber bracket that remains in a fixed position when the braking force is applied; and The target is configured to be connected to the push rod.

13. The sensing system according to claim 10, wherein: The sensing element is connected to a fixed mounting plate adjacent to a slack adjuster head that remains in a fixed position when the braking force is applied; and The target is connected to the slack adjuster head and is configured to move relative to the sensing element when the braking force is applied.

14. The sensing system according to claim 10, wherein: The target is connected to a fixed indicator plate adjacent to the cam shaft that remains in a fixed position when the braking force is applied; and The sensing element is connected to an adjusting arm such that the sensing element moves as the adjusting arm and the cam shaft rotate when the braking force is applied.

15. The sensing system according to claim 10, wherein, The sensing system is configured to measure the S-cam rotation angle, and the difference in displacement distance between the two cam followers is calculated based on the S-cam rotation angle.

16. The sensing system according to claim 15, wherein, The sensing system is configured to determine the current brake pad thickness at least in part based on the current S-cam rotation angle, the initial S-cam rotation angle, and the initial brake pad thickness.

17. The sensing system according to claim 16, wherein, The sensing system is configured to provide a warning based on an expected brake pad failure thickness.

18. The sensing system according to claim 16, wherein, The sensing system is configured to provide an indicator of at least one of: the distance before maintenance of the drum brake assembly is recommended; or the distance before failure of the drum brake assembly is expected.

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