Patent Application
20190128352
This disclosure relates to the monitoring of the physical state of a vehicle, and in particular the physical state of the brake pads of a vehicle. Monitoring of the physical state of the brake pads is performed using sensors to generate data that may be analyzed for diagnostic purposes.
The invention provides a system to perform real-time monitoring of the physical state of vehicle brake pads. Vehicle brakes rely on friction to control the speed and motion of the vehicle. The friction surfaces of the brakes suffer mechanical wear and require maintenance and replacement under normal operating conditions. Vehicle brakes comprise brake pads to provide an expendable friction surface in order to effectively provide braking functions while also provide inexpensive replacement of the friction surfaces. Monitoring the physical state of the brake pads provides drivers and technicians useful information regarding whether the brake pads need replacement.
Conventional brake pads use passive wear indicators, such as metal tabs that contact a rotor when the friction surface wears away enough to allow contact and make a noise from the contact providing a notification to a driver, and do not comprise an active real-time monitoring system. It would be advantageous to have a network of brake pad monitors in communication with each other or a vehicle to provide data and feedback regarding the condition of the brake pads. This data and feedback may be useful for vehicle passengers and technicians to perform diagnostics or maintain the vehicle. Further, the operational capacity of an autonomous vehicle may not be directly observed by a driver, including the operational capacity of the brakes. Thus, it may be additionally advantageous to provide self-diagnostic functions and notifications of safety features, such as braking components, in autonomous vehicles that may not respond as well to traditional feedbacks provided in non-autonomous vehicles.
One aspect of this disclosure is directed to a brake pad monitor device that is operable to measure the physical deterioration of a vehicular brake pad, and further operable for wireless communication between at least one other such brake pad monitor device.
According to another aspect of this disclosure, some embodiments of brake pad monitors may comprise energy harvesting functions.
Another aspect of this disclosure is directed to a system of system of brake pad monitors in wireless data communication, wherein one of the brake pad monitors operates in a primary control operating mode to coordinate the operations of the other brake pad monitors operating in a secondary subordinate operating mode.
A further aspect of this disclosure is directed to a method of power load balancing in a system of brake pad monitors having wireless data communication functions, the method being operable to optimize power consumption of the brake pad monitors.
The above aspects of this disclosure and other aspects will be explained in greater detail below with reference to the attached drawings.
The illustrated embodiments are disclosed with reference to the drawings. However, it is to be understood that the disclosed embodiments are intended to be merely examples that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed are not to be interpreted as limiting, but as a representative basis for teaching one skilled in the art how to practice the disclosed concepts.
Brake pad monitor 100 comprises a wireless unit 106 housing a pad processor 108, a memory 110, transmitter 112 and a receiver 114. Pad processor 108 controls the functions of the other components of brake pad monitor 100, and in some embodiments may be operable to perform analysis or diagnostic functions. Memory 110 may provide instructions to pad processor 108, or may be used to store data useful to the functions of brake pad monitor 100, such as data identifying the location of brake pad monitor 100 within the vehicle (e.g., front right wheel, etc.). In some embodiments, memory 110 may comprise a unique identification value describing brake pad monitor 100, for use to identify the brake pad monitor 100 when implemented within a network. Transmitter 112 and receiver 114 provide wireless communication functions to pad processor 108. Transmitter 112 and receiver 114 may be configured to communicate wirelessly with other devices via one or more of a Bluetooth specification, an RF (radio frequency) specification, cellular phone channels (analog or digital), cellular data channels, a Wi-Fi specification, a satellite transceiver specification, infrared transmission, a Zigbee specification, Local Area Network (LAN), Wireless Local Area Network (WLAN), a proprietary wireless network, or any other alternative configuration, protocol, or standard known to one of ordinary skill in the art. In some embodiments, transmitter 112 and receiver 114 may be embodied as single transceiver operable to both transmit and receive wireless signals. In the depicted embodiment, wireless unit 106 is disposed away from vehicle brake 102, but other embodiments may comprise other arrangements, such as wireless unit 106 being coupled to vehicle brake 102, associated brake calipers, the wheel or rotor, or any other arrangement known to one of ordinary skill in the art. In the depicted embodiment, wireless unit 106 further comprises a fidelity indicator 115, operable to measure the wireless connection fidelity between brake pad monitor 100 and other wireless devices and to generate fidelity data reflecting the wireless connection fidelity. Fidelity indicator 115 may be operable to generate fidelity data in the form of a single set of data corresponding to all wireless connectivity, or may be operable to generate separate sets of data corresponding to transmitter 112 and receiver 114 individually. In some embodiments, fidelity indicator 115 may be operable to generate sets of data that are distinct to any individual wireless device to which brake pad monitor 100 communicates wirelessly. In some embodiments, pad processor 108 may be operable to sort, analyze, or otherwise process the fidelity data generated by fidelity indicator 115.
Pad processor 108 is operable to control a number of pad sensors, the sensors being operable to provide data corresponding to the physical state and conditions of the brake pads 103. In the depicted embodiment, the pad sensors comprise an optical sensor 116, a thickness sensor 118 or a pressure sensor 120. In the depicted embodiment, brake pad monitor 100 comprises all of these sensors, but other embodiments may have other configurations comprising additional sensors or fewer sensors.
Optical sensor 116 may be configured to track an optical distance measurement of the thickness of brake pads 103. In some embodiments, optical sensor 116 may be configured to measure abrasion or optical density of the surface of brake pads 103. In the depicted embodiment, optical sensor 116 coupled to wireless unit 106, but other embodiments may comprise other arrangements. In some embodiments, optical sensor 116 may additionally measure other conditions detectable using optical emissions, such as infrared heat or reflectivity of the surfaces of vehicle brake 102. Some embodiments may comprise a plurality of optical sensors 116, arranged to optimize measurement of brake pads 103.
Thickness sensor 118 may be configured to directly measure the thickness of brake pads 103. In the depicted embodiment thickness sensor 118 is arranged alongside brake pad 103a, but other embodiments may have other arrangements, such as disposed within one of brake pads 103, or any other equivalent configuration known to one of ordinary skill in the art. In the depicted embodiment, thickness sensor 118 comprises a contact sensor operable to generate an electrical signal correlating to its thickness. For example, thickness sensor 118 may be comprised of a resistive material having a resistivity correlating to the thickness of the material. Thus, a consistent voltage applied to thickness sensor 118 may generate an increasing current draw during contact as the sensor erodes by friction. In such an embodiment, thickness sensor 118 may be configured to erode at substantially the same rate as brake pads 103. In some embodiments, thickness sensor 118 may be operable to generate other data useful for monitoring vehicle brake 102, such as the surface temperature of the rotor during active braking. Some embodiments may comprise a plurality of thickness sensors 118, arranged to optimize the measurement of brake pads 103.
Pressure sensor 120 may be configured to measure the mass of brake pads 103. In the depicted embodiment pressure sensor 118 is disposed between brake pad 103b and backing plate 104b, but other embodiment may have other arrangements. In the depicted embodiment, pressure sensor 120 measures the mass of brake pad 103b based upon the forces applied by brake pad 103b to backing plate 104b. As brake pad 103b is eroded by friction forces, pressure sensor 120 will measure a decreasing mass of brake pad 103b. In some embodiments, pressure sensor 120 may be operable to generate other data useful for monitoring vehicle brake 102, such as the pressure applied by vehicle brake 102 to the wheel or rotor. In the depicted embodiment, pressure sensor 120 is only operably coupled to brake pad 103b, but other embodiment may comprise additional pressure sensor arrangements, such as at least one pressure sensor 120 for each brake pad 103 utilized. Some embodiments may comprise a plurality of pressure sensors 120 for each brake pad 103, arranged to optimize the measurement of each brake pad 103.
Pad processor 108 is operable to collect the data generated by the sensors. In some embodiments, pad processor 108 may be operable to perform analysis using the collected data. In some embodiments, the data generated by the sensors may be stored in memory 110. In some embodiments, pad processor 108 may be operable to transmit the collected data to an external processor for analysis via transmitter 112. In some embodiments, pad processor 108 may be operable to perform analysis on the collected data or transmit the collected data depending on an active operational mode of pad processor 108. In some embodiments, pad processor 108 is operable to transmit commands to an external processor using transmitter 112 or receive commands from an external processor via receiver 114.
The components of brake pad monitor 100 are powered by a power supply 122. In the depicted embodiment, power supply 122 comprises a rechargeable battery, but other embodiments may comprise other configurations such as a capacitive power supply, an electric generator, or hardwire connection to an external power source. In the depicted embodiment, power supply 122 further comprises an electric charge sensor 124 operable to generate charge data corresponding to the total electric power that power supply 122 is currently operable to deliver to the components of brake pad monitor 100. The charge data may be utilized by pad processor 108 for analysis, or transmitted to an external processor using transmitter 112. In the depicted embodiment, all components of brake pad monitor 100 are powered by power supply 122, including the components housed within wireless unit 106, and the sensors 116, 118, and 120. In some embodiments, some components may be powered by other means.
In the depicted embodiment, brake pad monitor 100 further comprises an energy harvester 126. Energy harvester 126 is operable to generate electric power using the environmental conditions surrounding brake pad monitor 100. Energy harvester 126 may comprise a kinetic energy transducer, a thermal energy transducer, a radio frequency (RF) energy transducer, a piezoelectric transducer, or any other equivalent embodiment known to one of ordinary skill in the art without deviating from the disclosure herein. For example, in some embodiments energy harvester 126 may comprise a kinetic energy transducer that is operable to generate electric power when the vehicle brake 102 is engaged, slowing forward motion of the vehicle and shifting vehicular momentum to release harvestable energy. In another example, in some embodiments energy harvester 126 comprises a thermal transducer operable to generate electric energy by converting thermal energy in the form of heat in the environment of the vehicle brake 102, such as the heat generated by the friction forces when the brake pads 103 are pressed to the rotors. In another example, in some embodiments energy harvester 126 comprises an RF transducer operable to converter RF energy from wireless transmissions into electrical energy. RF transmission may include the wireless transmissions to and from the brake pad monitor 100 using transmitter 112 and receiver 114 respectively, but may also include RF transmissions in the environment unrelated to the operation of brake pad monitor 100, such as terrestrial radio broadcasts. In a further example, in some embodiments energy harvester 126 may comprise a piezoelectric transducer that is operable to generate electrical energy when brake pads 103 are compressed against the wheels or rotors during a braking operation. Other embodiments may comprise other forms of energy harvester 126 known to one of ordinary skill in the art without deviating from the teachings disclosed herein. In the depicted embodiment, energy harvester 126 is depicted as being coupled to wireless unit 106, but other embodiments may comprise other arrangements without deviating from the teachings disclosed herein. Some embodiments may comprise more than one energy harvester 126, either of a single form or of a variety of forms. In some such embodiments, individual components of brake pad monitor 100 may be independently powered by one of the plurality of energy harvesters 126. In some embodiments, energy harvester 126 may generate enough electrical power such that power supply 122 is unnecessary for proper function of the other components of brake pad monitor 100. In some such embodiments, brake pad monitor 100 may not comprise a power supply 122. In the depicted embodiment, energy harvester 126 is operable to charge power supply 122, including recharging power supply 122 when electric charge sensor 124 indicates that power supply 122 is below its full charge capacity.
In the depicted embodiment, brake pad monitor 100 may be operated in a plurality of operating modes. In a primary control operating mode, pad processor 108 functions to coordinate collaborative functions of a network of brake pad monitors 100. In a secondary support mode, pad processor 108 functions as a subordinate process in a network, its functions being coordinated by another brake pad monitor 100 operating in the primary control mode. Other embodiments may comprise other modes of operation, such as an independent mode for brake pad monitors that are not part of a network of other brake pad monitors.
In the depicted embodiment, brake pad monitor 204a is the primary mode monitor 204′ operating in a primary control mode, and is coordinating the functions of brake pad monitors 204b, 204c, and 204d. When serving as primary mode monitor 204′, brake pad monitor 204a wirelessly communicates with brake pad monitor 204b using a monitor channel 206ab. Monitor channel 206ab exists when brake pad monitor 204a is in the primary control mode and brake pad monitor 204b is in the secondary support mode. When serving as primary mode monitor 204′, brake pad monitor 204a wirelessly communicates with brake pad monitor 204c using a monitor channel 206ac. Monitor channel 206ac exists when brake pad monitor 204a is in the primary control mode and brake pad monitor 204c is in the secondary support mode. When serving as primary mode monitor 204′, brake pad monitor 204a wirelessly communicates with brake pad monitor 204d using a monitor channel 206ad. Monitor channel 206ad exists when brake pad monitor 204a is in the primary control mode and brake pad monitor 204d is in the secondary support mode. In the depicted embodiment, only one of brake pad monitors 204 may serve as primary mode monitor 204′ and operate in the primary control mode. The remaining brake pad monitors 204 within the network operate in the secondary subordinate mode. Other embodiments may comprise other configurations. One such configuration may comprise a number of sub-networks, each of the sub-networks having a respective primary mode monitor 204′ to coordinate an additional number of brake pad monitors operating in the secondary subordinate mode. In some such embodiments, primary mode monitors 204′ may each communicate directly with an external processor. In some such embodiments, one brake pad monitor 204 may operate in a third mode to which the primary mode monitors 204′ are subordinate, the third mode being operable to collate the generated data sets from each subnetwork. Such embodiments may be advantageous for use with vehicles having a larger quantity of brake pads (e.g., an eighteen-wheel truck).
As depicted in
Primary mode monitor 204′ may be further operable to transmit control commands to the other brake pad monitors (brake pad monitors 204b, 204c, and 204d as depicted in
The primary mode monitor 204′ is further operable to connect wirelessly to an external processor, such as the diagnostic processor 208 via diagnostic channel 210. Diagnostic channel 210 exists between diagnostic processor 208 and the primary mode monitor 204′ (e.g., brake pad monitor 204a in the depicted embodiment of
In the depicted embodiment, primary mode monitor 204′ is further operable to connect wirelessly to a vehicle processor 212 instead of, or in addition to, diagnostic processor 208. In the depicted embodiment, vehicle processor 212 is operable to perform some or all of the functions of diagnostic processor 208. In some embodiments, vehicle processor 212 may be operable to perform additional functions beyond what functions diagnostic processor 208 is capable, or vice-versa. A vehicle channel 214 exists between vehicle processor 212 and a primary mode monitor 204′ (e.g., brake pad monitor 204a in the depicted embodiment). In the depicted embodiment, vehicle processor 212 is embodied within a dongle device configured to interface with the diagnostic port of a vehicle (e.g., an OBD-II port), but other embodiments may comprise other configurations of vehicle processor 212 such as an on-board vehicle processor, a native processor disposed within a vehicle head unit, an aftermarket processor installed in the vehicle, a telematics system, or any other equivalent alternative known to one of ordinary skill in the art without deviating from the teachings disclosed herein. In some embodiments, vehicle processor 212 may be operable to receive data transmitted by a primary mode monitor 204′. In some embodiments, vehicle processor 212 is operable to perform analysis upon the data received from a primary mode monitor 204′. In some embodiments, vehicle processor 212 is operable to transmit commands to a primary mode monitor 204′, such as control commands intended for the primary mode monitor 204′ (e.g., brake pad monitor 204a in
In the depicted embodiment, diagnostic processor 208 and vehicle processor 212 are in wireless communication using an interconnect channel 216. Interconnect channel 216 may provide a communication channel that makes diagnostic processor 208 and vehicle channel 212 operable to each contribute to the functions thereof without redundant operations. In some embodiments, interconnect channel 216 may enable diagnostic processor 208 and vehicle processor 212 to operate in a cooperative manner with respect brake pad monitors 204. In some embodiments, only one of diagnostic processor 208 or vehicle processor 212 may be present. In some embodiments, multiple additional processors of varying types may be included instead of, or in addition to diagnostic processor 208 or vehicle processor 212.
A primary mode monitor 204′ may expend extra power performing the additional transmissions to each of the other brake pad monitors 204 in a secondary subordinate mode, or the additional transmissions to one of diagnostic processor 208 or vehicle processor 212. Additionally, if the wireless connection fidelity between a primary mode monitor 204′ and another element of brake pad monitor system 200 is poor, the primary mode monitor 204′ may expend extra power in accurately transmitting or receiving data or commands. Advantageously, a primary mode monitor 204′ may initiate a load-balancing procedure to shift itself into the secondary subordinate mode after nominating another of brake pad monitors 204 in brake pad monitor system 200 to operate in the primary control mode. This load-balancing procedure effectively shifts the status of primary mode monitor 204′ to a different one of the brake pad monitors 204 within brake pad monitor system 200. Advantageously, the load-balancing procedure may extend the operability of brake pad monitor system 200 by optimizing power consumption, thereby minimizing the risk of failure in the system caused by an expended power supply 122 (see
In some embodiments, the load-balancing procedure may be initiated based upon the electric charge status indicated by the electric charge sensor 124 (see
Selection of the next brake pad monitor 204 to serve as the primary mode monitor 204′ during the load-balancing procedure may be performed based upon the conditions of brake pad monitor system 200. In one embodiment, the brake pad monitor 204 having the highest electric charge indicated by its respective electric charge sensor 124 may be selected. In one embodiment, the brake pad monitor 204 having the highest wireless connection fidelity indicated by its respective fidelity indicator 115 (see
Selection of a brake pad monitor 204 to serve as an initial primary mode monitor 204′ may be required in some embodiments. Initial selection of the primary mode monitor 204′ may be a one-time event upon installation or initialization of brake pad monitor system 200 or may be routinely performed. In some embodiments, the initial selection of a primary mode monitor 204′ is performed upon each engine startup of the vehicle. In some embodiments, the initial selection of a primary mode monitor 204′ is determined by vehicle processor 212 upon initial activation of vehicle processor 212. In some embodiments, the initial selection of a primary mode monitor 204′ is determined by diagnostic processor 208 upon initial activation of diagnostic processor 208. In some embodiments, one of brake pad monitors 204 may be designated by the system as the initial primary mode monitor 204′, and the system may utilize the load-balancing procedure to adjust operation of the brake pad monitor system 200 if the designated brake pad monitor 204 is not the optimal selection.
At step 304, the primary brake pad monitor initiates a load-balancing procedure, such as if its power supply 122 has an electric charge lower than the threshold level or if its fidelity indicator shows wireless connection fidelity between itself as primary mode monitor and another element of the brake pad monitor system is below a threshold value. If neither condition is met, the system returns to step 302 to continue normal operation and monitoring of the status of primary brake pad monitor. Other embodiments may comprise other reasons for the primary mode monitor to initiate the load-balancing procedure.
If the primary mode monitor initiates the load-balancing procedure, the system continues to step 306 where the primary brake pad monitor selects which of the secondary brake pad monitors 204 shall serve as the next primary mode monitor. The selection of the next primary mode monitor may be in response to the reason for initiating the load-balancing procedure. For example, if primary brake pad monitor initiates the load-balancing procedure in response to low power, the selection of the next primary mode monitor may be based upon which of the secondary brake pad monitors has a power supply with the greatest remaining electric charge. In another example, if the primary brake pad monitor initiates the load-balancing procedure in response to poor wireless connection fidelity, the selection of the next primary mode monitor may be based upon which of the secondary brake pad monitors indicating the greatest wireless connection fidelity. Some embodiments may select the next primary mode monitor in response to other causes of initiating the load-balancing procedure.
At step 308, the operating modes of the brake pad monitors are adjusted to operate with the next primary mode monitor in control, and the logic flow is transferred to the new primary brake pad monitor. Accordingly, the former primary brake pad monitor shifts from a primary control mode to a secondary subordinate mode. The brake pad monitor selected as the next primary mode monitor shifts from a secondary subordinate mode to the primary control mode. By way of example, and not limitation, if brake pad monitor 204b has been selected as the next primary mode monitor 204′, then brake pad monitor 204b shifts into the primary control mode (see
After the brake pad monitors shift their operation and establish the proper communication channels in step 308, the system returns to step 302 to resume normal operation and monitor for another initiation of the load-balancing procedure.
In
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosed apparatus and method. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure as claimed. The features of various implementing embodiments may be combined to form further embodiments of the disclosed concepts.
| Number | Date | Country | |
|---|---|---|---|
| 62579634 | Oct 2017 | US |
