Wheel monitoring system

Abstract

To provide a wheel monitoring system that can detect theft of wheel, tire change or the like while suppressing electrical power consumption due to transmission of information by a tire sensor.SOLUTION: A wheel monitoring system includes a tire sensor 2. The tire sensor 2 determines that wheels 10a-10d are stollen when an acceleration sensor 22 detects a predetermined acceleration change while a vehicle 10 is in a parking state. The tire sensor 2 determines that there is a possibility that tire rotation or change has been carried out when the acceleration sensor 22 detects a predetermined acceleration change while the vehicle 10 is in a stopping state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a wheel monitoring system. [Background technology]

[0002] Conventionally, there is known a vehicle theft notification system that transmits warning information to the outside of the vehicle based on, for example, a detection that the amount of change in acceleration applied to the tires when the vehicle's main power source is turned off and the vehicle doors are locked exceeds a first acceleration range (see, for example, Patent Document 1).

[0003] The system described in Patent Document 1 detects the air pressure of each tire using a tire sensor (i.e., a TPMS transmitter) attached to each tire. An on-board device mounted on the body of the vehicle periodically obtains tire information including the tire air pressure from the tire sensor and determines whether or not the amount of change in acceleration applied to the tire has exceeded a first acceleration width. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-141237 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have been studying a method for detecting wheel theft by monitoring the acceleration of tires. However, when the acceleration of tires is monitored by an on-board device as in the conventional technology, the tire sensor needs to transmit tire information frequently, and the tire sensor consumes a lot of power due to the transmission of information. This is true not only when detecting wheel theft, but also when detecting tire changes, etc.

[0006] The present disclosure aims to provide a wheel monitoring system capable of detecting wheel theft, tire replacement, etc., while suppressing power consumption caused by information transmission from tire sensors. [Means for solving the problem]

[0007] The invention described in claim 1 is A wheel monitoring system applied to a vehicle (10) having a body (11) and a plurality of wheels (10a to 10d) including tires, a tire sensor (2) including an acceleration sensor (22) provided on a wheel and outputting an acceleration that changes with the rotation of the wheel; An on-board device (3) provided in a vehicle body, The tire sensor and the on-board device are configured to be able to communicate bidirectionally, The on-board device determines whether the vehicle is in a parked state, a stopped state, or a moving state based on the vehicle's traveling speed, the state of the vehicle doors, and the on / off state of the vehicle ignition switch, and transmits information including the determination result to the tire sensor. The tire sensor identifies the current vehicle condition based on information notified by the onboard unit, and determines whether the vehicle has been stolen, tires have been rotated, or tires have been replaced based on a combination of the identified vehicle condition and the sensor output of the speed sensor.

[0008] In this manner, if the vehicle state determination result from the vehicle-mounted device is notified to the tire sensor 2 (synchronization of vehicle state), it is sufficient for the tire sensor to receive information from the vehicle-mounted device only once each time the vehicle state changes, so power consumption of the tire sensor can be sufficiently suppressed. Therefore, it is possible to detect wheel theft, tire change, etc. while suppressing power consumption caused by information transmission from the tire sensor.

[0009] In the invention described in claim 3, when the vehicle is parked and a predetermined change in acceleration is detected by the acceleration sensor, the tire sensor determines that a wheel has been stolen.

[0010] By performing the wheel theft determination on the tire sensor side in this manner, there is no need to increase the frequency of information transmission from the tire sensor, making it possible to detect wheel theft while reducing power consumption due to information transmission from the tire sensor.

[0011] In the invention described in claim 4, when the acceleration sensor detects a predetermined change in acceleration while the vehicle is stopped, the tire sensor determines that there is a possibility that tires have been rotated or replaced.

[0012] In this way, if the tire sensor is configured to determine whether a tire change has occurred based on the detection results of the acceleration sensor, it is possible to detect a tire change without increasing the frequency of information transmission from the tire sensor. Therefore, it is possible to detect a tire change while suppressing power consumption due to information transmission from the tire sensor.

[0013] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0014] [Figure 1] 1 is an overall configuration diagram of a wheel monitoring system according to an embodiment; [Diagram 2] FIG. 2 is a block diagram of a tire sensor. [Diagram 3] FIG. 2 is a block diagram of an in-vehicle device. [Figure 4] 5 is a flowchart showing a flow of a control process executed by a tire sensor. [Diagram 5] 5 is a flowchart showing a flow of a theft detection process executed by a tire sensor. [Figure 6] FIG. 2 is an explanatory diagram for explaining a state of a vehicle. [Figure 7] 5 is a flowchart showing a flow of a theft alarm process executed by a tire sensor. [Figure 8]5 is a flowchart showing a procedure for a theft alarm process executed by an on-board device of the own vehicle. [Figure 9] 6 is a flowchart showing a procedure for a theft tracking process executed by a tire sensor. [Figure 10] FIG. 13 is an explanatory diagram for explaining a theft master code. [Figure 11] 6 is a flowchart showing the flow of a theft tracking process executed by an in-vehicle device of another vehicle; [Figure 12] 5 is a flowchart showing a flow of a detection process for a tire change or the like executed by a tire sensor. [Figure 13] 6 is a flowchart showing a flow of a response process such as tire replacement executed by the vehicle-mounted device. [Figure 14] 10 is an explanatory diagram for explaining the relationship among door state, vehicle speed, vehicle state, two-way communication, acceleration change, and judgment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An embodiment of the present disclosure will be described with reference to Figs. 1 to 14. Fig. 1 is a diagram showing a wheel monitoring system. Front, rear, left and right in Fig. 1 refer to front, rear, left and right of a vehicle 10. In addition, in the following, when the four wheels 10a to 10d attached to the vehicle 10 are to be described separately, the four wheels 10a to 10d may be referred to as a left front wheel FL, a right front wheel FR, a left rear wheel RL and a right rear wheel RR.

[0016] The wheel monitoring system has a function of detecting wheel theft and a function of detecting whether or not a tire has been changed. That is, the wheel monitoring system functions as a wheel theft detection system and also as a tire change detection system. As shown in Fig. 1, the wheel monitoring system detects theft of wheels 10a to 10d using multiple tire sensors 2, an in-vehicle device 3, a brake ECU 4, a meter 5, a door lock ECU 6, and a mobile communication device 7.

[0017] The tire sensors 2 and the vehicle-mounted device 3 are components of a tire pressure monitoring system (hereinafter referred to as TPMS). The TPMS uses the tire sensors 2 and the vehicle-mounted device 3, as well as information from the brake ECU 4, to perform autolocation to automatically detect the wheel positions.

[0018] The brake ECU 4 is an electronic control device for brake control. The brake ECU 4 acquires wheel speed pulses obtained from detection signals of the wheel angle sensors 4a to 4d provided corresponding to the wheels 10a to 10d, and transmits the information to the vehicle-mounted device 3 for wheel position detection.

[0019] The wheel angle sensors 4a to 4d are generally called wheel speed sensors. These sensors output signals corresponding to the tooth positions of gears that rotate with the axles as wheel speed pulses, but since they are used here to obtain the angles at which the tire sensor 2 exists relative to the central axes of the wheels 10a to 10d, they are called "wheel angle sensors."

[0020] The tire sensors 2 are attached to the wheels 10a-10d, detect the air pressure of the tires attached to the wheels 10a-10d, and transmit the tire pressure-related information indicating the detection result stored in a frame. The vehicle-mounted device 3 is attached to the vehicle body 11 of the vehicle 10, and receives the frame transmitted from the tire sensors 2, and detects the tire pressure by performing various processes and calculations based on the information stored in the frame.

[0021] As shown in FIG. 2, the tire sensor 2 includes an air pressure detection unit 21, an acceleration sensor 22, a first microcomputer 23, and a tire radio 24, and each unit is driven by power supplied from a battery (not shown).

[0022] The tire pressure detection unit 21 includes a pressure sensor 21a and a temperature sensor 21b, and outputs a detection signal corresponding to the tire pressure and a detection signal corresponding to the temperature. The acceleration sensor 22 is used to detect the rotation angle of the tire sensor 2, the traveling speed (i.e., vehicle speed) of the vehicle 10, and detect theft. The acceleration sensor 22 is, for example, configured with a two-axis acceleration sensor capable of detecting the radial acceleration and circumferential acceleration of each of the wheels 10a to 10d.

[0023] The first microcomputer 23 constitutes the control unit of the tire sensor 2 and includes a CPU, memories such as ROM and RAM, an I / O, etc. The first microcomputer 23 executes a predetermined process according to a program stored in the built-in memory. The memory stores individual ID information including a unique tire ID for identifying each tire sensor 2 and a vehicle ID unique to the vehicle for identifying the vehicle itself.

[0024] The first microcomputer 23 receives, for example, detection signals from the pressure sensor 21a and the temperature sensor 21b, processes the signals and, if necessary, manipulates them, and stores the information relating to the tire pressures together with the ID information of each tire sensor 2 in a frame.

[0025] The first microcomputer 23 also monitors the detection signal from the acceleration sensor 22 and performs vehicle movement determination to determine the angle of each tire sensor 2 and whether the vehicle 10 is moving. After creating a frame, the first microcomputer 23 transmits the frame from the tire radio 24 to the vehicle-mounted device 3 based on the result of the vehicle movement determination. Hereinafter, information related to tire pressure is also simply referred to as tire information.

[0026] Specifically, the first microcomputer 23 repeatedly transmits frames at a predetermined timing while the vehicle 10 is traveling. The first microcomputer 23 determines whether the vehicle 10 is traveling or not based on the detection result of the acceleration sensor 22. The first microcomputer 23 determines that the vehicle 10 is traveling when the acceleration detected by the acceleration sensor 22 is equal to or greater than a certain value. The certain value is set to a value equivalent to the centrifugal acceleration occurring while traveling at about 5 km / h, for example.

[0027] In addition, since the acceleration sensor 22 outputs a detection signal corresponding to the rotation of each of the wheels 10a to 10d, the detection signal includes a gravitational acceleration component during driving, and has an amplitude corresponding to the wheel rotation. Therefore, the position of the acceleration sensor 22, i.e., the rotation angle of the tire sensor 2, can be grasped based on this amplitude.

[0028] The tire radio 24 includes a first transmission / reception circuit 241 and a first communication antenna 242. The first transmission / reception circuit 241 is a communication circuit that performs bidirectional communication with the in-vehicle device 3 through the first communication antenna 242. The first transmission / reception circuit 241 performs wireless communication based on a communication method such as BLE. BLE is an abbreviation for Bluetooth (registered trademark) Low Energy. Note that the first transmission / reception circuit 241 may perform wireless communication based on a communication method other than BLE.

[0029] The first communication antenna 242 is an antenna for performing bidirectional communication with the vehicle-mounted device 3. By including the tire wireless device 24, the tire sensor 2 is able to perform bidirectional communication with the vehicle-mounted device 3, not just unidirectional communication from the tire sensor 2 to the vehicle-mounted device 3.

[0030] Specifically, the tire sensor 2 performs wireless communication with the vehicle-mounted device 3 based on BLE. BLE-based wireless communication allows unicast communication, which is bidirectional communication, and broadcast communication, which is one-way communication.

[0031] Unicast communication is a communication method in which a virtual connection (a virtual dedicated communication path) is established with a partner before starting communication, and data is transmitted and received through the established connection. The tire sensor 2 is capable of transmitting and receiving data to and from the vehicle-mounted device 3 of the vehicle by unicast communication.

[0032] On the other hand, broadcast communication, also known as connectionless communication, is a communication method in which data is sent unilaterally without checking the status of the other party before starting communication. By using broadcast communication, the tire sensor 2 can send and receive data not only to the on-board unit 3 of its own vehicle, but also to on-board units 3 of other vehicles around the tire sensor 2.

[0033] The tire sensor 2 thus configured detects the tire pressure and the temperature inside the tire, and while the vehicle 10 is traveling, transmits a frame at a timing when the angle of the tire sensor 2 reaches a predetermined angle.

[0034] In addition, the tire sensor 2 detects theft of the wheels 10a-10d based on the acceleration that changes with the rotation of the wheels 10a-10d when the vehicle 10 is stopped and traveling at a speed less than a predetermined speed (e.g., 5 km / h). Of the tire sensor 2, the hardware and software for detecting theft of the wheels 10a-10d constitute a "tire monitoring unit 23a" for determining whether the wheels 10a-10d have been stolen.

[0035] On the other hand, the vehicle-mounted device 3 is provided in the vehicle body 11. As shown in FIG. 3, the vehicle-mounted device 3 includes an in-vehicle wireless device 31 and a second microcomputer 33. The vehicle-mounted device 3 acquires the number of edges of the teeth of the gears rotated together with the wheels 10a to 10d or the tooth positions indicated by the number of teeth by acquiring wheel speed pulses from the brake ECU 4 as described later through an in-vehicle LAN (Local Area Network) such as a CAN (Controller Area Network). In the following description, the number of edges is taken as an example of the gear information, but the number of teeth may also be used. The vehicle-mounted device 3 also acquires the detection value of a steering angle sensor (not shown) (i.e., the steering angle of the steering wheel) through the in-vehicle LAN.

[0036] The in-vehicle wireless device 31 includes a second communication antenna 311 and a second transmission / reception circuit 312. The second communication antenna 311 is an antenna for performing bidirectional communication with each tire sensor 2. The second communication antenna 311 is used not only for receiving frames and the like sent from each tire sensor 2, but also for transmitting signals to each tire sensor 2. The second communication antenna 311 may be an internal antenna disposed within the main body of the in-vehicle wireless device 3, or may be an external antenna with wiring extended from the main body.

[0037] The second transmission / reception circuit 312 is a communication circuit that communicates bidirectionally with each tire sensor 2 through the second communication antenna 311. The second transmission / reception circuit 312 performs wireless communication based on a communication method such as BLE. The second transmission / reception circuit 312 inputs a transmission frame received from each tire sensor 2 by the second communication antenna 311, and functions as an input unit that sends the frame to the second microcomputer 33. When the second transmission / reception circuit 312 receives a frame through the second communication antenna 311, it transmits the received signal to the second microcomputer 33.

[0038] The second microcomputer 33 constitutes a control unit in the vehicle-mounted device 3 and includes a CPU, memories such as a ROM and a RAM, an I / O, etc. The second microcomputer 33 executes wheel position detection processing and tire air pressure detection processing according to programs stored in the built-in memory.

[0039] In the wheel position detection process, wheel position detection is performed to identify which of the wheels 10a to 10d the tire sensor 2 is attached to. Specifically, the second microcomputer 33 performs wheel position detection based on information obtained from the brake ECU 4 and information obtained from each tire sensor 2. The second microcomputer 33 obtains, from the brake ECU 4, wheel speed pulses, which are output signals from the wheel angle sensors 4a to 4d provided corresponding to each of the wheels 10a to 10d, at a predetermined cycle, for example, every 10 ms.

[0040] The wheel speed pulse is information indicating the tooth position of the gear that rotates together with each wheel 10a-10d. The wheel angle sensors 4a-4d are, for example, configured by electromagnetic pickup type sensors arranged facing the teeth of the gears, and change the detection signal as the teeth of the gears pass. In this type of wheel angle sensor 4a-4d, a square pulse wave corresponding to the passing of the teeth is output as a detection signal, and the rising and falling edges of the square pulse wave indicate the passing of the edges of the teeth of the gears. The brake ECU 4 counts the number of edges of the teeth of the gears, that is, the number of passing edges, as wheel speed pulses from the number of rising and falling edges of the detection signals of the wheel angle sensors 4a-4d. For example, if the number of teeth of the gears is 48, the number of edges is counted as 0 to 95, a total of 96, when the gears rotate once. The brake ECU 4 then transmits the number of edges of the teeth at that time to the second microcomputer 33 as a wheel speed pulse at every predetermined period.

[0041] The second microcomputer 33 acquires wheel speed pulses from the wheel angle sensors 4a-4d and converts the amount of change in the acquired wheel speed pulses into the rotation angle of each of the wheels 10a-10d. If the total number of wheel speed pulses during one rotation of the wheels 10a-10d is 96, the rotation angle of the wheels 10a-10d per one wheel speed pulse is 3.75°. Therefore, by multiplying the amount of change in the wheel speed pulses by 3.75°, the amount of change in the wheel speed pulses can be converted into the rotation angle of each of the wheels 10a-10d.

[0042] The second microcomputer 33 compares the rotation angles of the wheels 10a-10d based on the wheel angle sensors 4a-4d with the rotation angles of the tire sensors 2 based on the tire sensors 2, and associates those whose rotation angles fall within a predetermined range. This makes it possible to perform wheel position detection that identifies which of the wheels 10a-10d each tire sensor 2 is attached to.

[0043] In the tire pressure detection process, the tire pressure of each wheel 10a-10d to which each tire sensor 2 is attached is detected. Specifically, the second microcomputer 33 associates the ID information of each tire sensor 2 with the position of each wheel 10a-10d to which each tire sensor 2 is attached based on the result of the wheel position detection, and stores the ID information. After that, the tire pressure of each wheel 10a-10d is detected by calculating a tire pressure conversion value at a predetermined temperature based on the ID information and tire information stored in the transmission frame from each tire sensor 2. Then, an electric signal according to the tire pressure detection result is output to the meter 5 through an in-vehicle LAN such as CAN. For example, the second microcomputer 33 outputs a signal indicating the tire pressure of each wheel 10a-10d to the meter 5. In addition, the second microcomputer 33 detects a decrease in tire pressure by comparing the tire pressure with a predetermined judgment threshold, and when the second microcomputer 33 detects a decrease in tire pressure, it outputs a signal to that effect to the meter 5. This notifies the meter 5 that the tire pressure of one or more of the four wheels 10a to 10d has decreased, and the meter 5 displays this information.

[0044] The meter 5 serves as a display unit provided in the vehicle cabin and displays various information. The meter 5 displays various information when the power is on, specifically when an accessory switch (hereinafter referred to as ACC) or a start switch such as an ignition switch IG is on. The meter 5 basically displays information when the power is on.

[0045] The meter 5 is disposed in a location visible to the driver, and is configured, for example, by a multi-information display installed in the instrument panel of the vehicle 10, a display of a navigation device, or the like. When the meter 5 receives a signal indicating a drop in tire air pressure from, for example, the second microcomputer 33 in the vehicle-mounted device 3, the meter 5 notifies the driver of the drop in tire air pressure of the wheel in question by displaying the drop in tire air pressure while identifying the wheel in question.

[0046] The door lock ECU 6 is a control device that controls locking and unlocking of the doors of the vehicle 10. In a door-locked state where the doors are locked, the door lock ECU 6 outputs a door lock signal to the in-vehicle device 3. In a door-unlocked state where the doors are unlocked, the door lock ECU 6 outputs a door unlock signal to the in-vehicle device 3. The door lock ECU 6 is always operating while the ignition switch IG is on, during the period from when the ignition switch IG is off until the doors are locked, and during the period after the ignition switch IG is turned off and the doors are locked.

[0047] The mobile communication device 7 is a wireless communication unit for communicating with a communication destination outside the vehicle 10. When the ignition switch IG is turned on, the mobile communication device 7 becomes active and communicates with a service center 73 connected to the communication network 72 (a mobile communication network, the Internet, etc.) by wirelessly connecting to a wireless base station 71 connected to the communication network 72.

[0048] The service center 73 communicates with a user terminal 75 (a terminal carried by the user of the vehicle 10) via the communication network 72 and the base station 74. The service center 73 also communicates with a security system (not shown) via the communication network 72. The security system is a communication device owned and operated by a security company or the police.

[0049] Next, various control processes including theft detection of the wheels 10a-10d executed by each tire sensor 2 and the vehicle-mounted device 3 will be specifically described with reference to Fig. 4 to Fig. 12. The control process shown in Fig. 4 is executed by each tire sensor 2 periodically or irregularly.

[0050] As shown in Fig. 4, the tire sensor 2 executes theft detection processing in step S100. This theft detection processing is processing for determining whether theft of the wheels 10a to 10d has been detected. Details of the theft detection processing will be described with reference to Fig. 5.

[0051] 5, in step S101, the tire sensor 2 reads various pieces of information. Specifically, the tire sensor 2 reads information related to a change in acceleration from the acceleration sensor 22. In addition, the tire sensor 2 reads, via the in-vehicle device 3, on / off information of the ignition switch IG, door information including the door locked and unlocked states, and the like.

[0052] In step S102, the tire sensor 2 determines whether the vehicle 10 is in a stopped state. In this specification, as shown in Fig. 6, a state in which the traveling speed of the vehicle 10 (i.e., the vehicle speed) is less than 5 km / h, such as a "parked state" and a "stopped state", is defined as the "stopped state" of the vehicle 10.

[0053] Here, the "parked state" is a state in which the doors are locked and the ignition switch IG is off when the vehicle speed is less than 5 km / h. The stopped state is a state in which the ignition switch IG is on or the doors are unlocked when the vehicle speed is less than 5 km / h. The running state is a state in which the ignition switch IG is on and the vehicle speed is 5 km / h or more. The states of the vehicle 10, such as the "parked state", "stopped state", and "running state", can be determined based on the running speed of the vehicle 10, the state of the doors, and the on / off state of the ignition switch IG.

[0054] If the vehicle 10 is not stopped but is moving, there is no possibility of theft, so the tire sensor 2 skips the subsequent processes and exits from this process. On the other hand, if the vehicle 10 is not stopped, the tire sensor 2 determines in step S103 whether the doors are locked and the ignition switch IG is turned off. That is, the tire sensor 2 determines whether the vehicle 10 is in a "parked state." Note that when the vehicle 10 is stopped, the doors are locked and the ignition switch IG is turned off, which is the "parked state" of the vehicle 10.

[0055] If the result of this determination process is that the doors of the vehicle 10 are unlocked or the ignition switch IG is on (i.e., the vehicle 10 is in a "parked" state), the tire sensor 2 skips the subsequent processes and exits from this process. On the other hand, if the doors of the vehicle 10 are locked and the ignition switch IG is off (i.e., the vehicle 10 is in a "parked" state), the tire sensor 2 proceeds to step S104. In step S104, the tire sensor 2 determines whether or not a predetermined acceleration change has been detected by the acceleration sensor 22. The predetermined acceleration change is set to the range of fluctuation in the detection value of the acceleration sensor 22 that occurs when changing tires, for example.

[0056] If the determination result in step S104 is an affirmative determination (YES), it means that the acceleration sensor 22 detects a predetermined acceleration change when the vehicle 10 is stopped, the doors are locked, and the ignition switch IG is off (i.e., parked). When changing tires or the like, the doors are often unlocked or the ignition switch IG is on for convenience of the work. On the other hand, the wheels 10a to 10d are almost always stolen when the vehicle 10 is stopped, the doors are locked, and the ignition switch IG is off (i.e., parked). If the acceleration sensor 22 detects a predetermined acceleration change when the vehicle 10 is stopped, the doors are locked, and the ignition switch IG is off (i.e., parked), there is a high possibility that the wheels 10a to 10d have been stolen. Therefore, when the acceleration sensor 22 detects a predetermined change in acceleration while the vehicle 10 is stopped, the doors are locked, and the ignition switch IG is off (i.e., parked), the tire sensor 2 turns on the first theft flag in step S105. This first theft flag is a flag that is turned on when the wheels 10a-10d are stolen. Since the first theft flag is turned on when the acceleration sensor 22 detects a predetermined change in acceleration, it is assumed that the wheels 10a-10d are present around the vehicle 10.

[0057] On the other hand, if the determination result in step S104 is negative (NO), that is, if the acceleration sensor 22 has not detected a predetermined change in acceleration, the tire sensor 2 checks in step S106 whether communication with the vehicle-mounted device 3 is possible. Then, in step S107, the tire sensor 2 checks whether communication with the vehicle-mounted device 3 has been interrupted. This communication check, for example, checks whether a connection for unicast communication with the vehicle-mounted device 3 can be established.

[0058] When communication with the vehicle-mounted device 3 is possible, it is considered that the wheels 10a to 10d are attached to the vehicle 10. Therefore, when communication with the vehicle-mounted device 3 is possible, the tire sensor 2 skips the subsequent processes and exits from this process.

[0059] On the other hand, if communication with the vehicle-mounted device 3 is interrupted, it is assumed that the wheels 10a-10d to which the tire sensors 2 are attached have been stolen and taken away to a location far away from the vehicle-mounted device 3 attached to the vehicle body 11. For this reason, if communication with the vehicle-mounted device 3 is interrupted, the tire sensor 2 turns on a second theft flag in step S108. The second theft flag, like the first theft flag, is a flag that is turned on when the wheels 10a-10d are stolen. Since the second theft flag is turned on when communication between the tire sensor 2 and the vehicle-mounted device 3 is interrupted, it is assumed that the wheels 10a-10d are in a location far away from the vehicle 10.

[0060] The above is the description of the theft detection process. When the theft detection process in step S100 in Fig. 4 is completed, the tire sensor 2 proceeds to step S110 and determines whether or not the first theft flag is on.

[0061] If the first theft flag is on, the tire sensor 2 executes the theft alarm process in step S120 and then exits from this process. This theft alarm process will be described with reference to FIGS.

[0062] 7, in step S121A, the tire sensor 2 transmits a theft signal to the vehicle-mounted device 3 of the vehicle by unicast communication. This theft signal is a signal indicating that the wheels 10a to 10d of the vehicle have been stolen, and is receivable only by the vehicle-mounted device 3 of the vehicle for security reasons.

[0063] As shown in FIG. 8, the vehicle-mounted device 3 of the vehicle determines in step S121B whether or not it has received a theft signal from the tire sensor 2 attached to the wheels 10a-10d of the vehicle. As a result, if it has received a theft signal from the tire sensor 2, the vehicle-mounted device 3 of the vehicle proceeds to step S122B, transmits a response signal to the tire sensor 2 that is the source of the theft signal, and notifies the theft of the wheels 10a-10d using the in-vehicle notification unit. For example, the vehicle-mounted device 3 of the vehicle notifies people in the vicinity of the vehicle 10 of the theft of the wheels 10a-10d by emitting an alarm sound from an in-vehicle alarm device (not shown) or turning on the hazard lights. In this example, the in-vehicle alarm device and the hazard lights constitute the "notification unit." When the ignition switch IG is turned on, the vehicle-mounted device 3 of the vehicle may be configured to notify the theft to the service center 73 or the like using the mobile communication device 7, for example.

[0064] After transmitting the theft signal, the tire sensor 2 determines in step S122A whether or not a response signal has been received from the vehicle-mounted device 3 of the vehicle. As a result, if a response signal has been received from the vehicle-mounted device 3 of the vehicle, communication with the vehicle-mounted device 3 of the vehicle has been established. Therefore, if a response signal has been received from the vehicle-mounted device 3 of the vehicle, the tire sensor 2 exits this process.

[0065] On the other hand, if a response signal is not received from the vehicle-mounted device 3 of the vehicle, this means that communication with the vehicle-mounted device 3 of the vehicle has been interrupted. Therefore, if a response signal is not received from the vehicle-mounted device 3 of the vehicle, the tire sensor 2 proceeds in step S123A to the theft tracking process in step S140 of FIG.

[0066] Returning to FIG. 4, if it is determined in the determination process of step S110 that the first theft flag is OFF, the tire sensor 2 determines in step S130 whether or not the second theft flag is ON.

[0067] If the second theft flag is on, the tire sensor 2 executes the theft tracking process in step S140 and then exits from this process. This theft tracking process will be described with reference to FIGS.

[0068] As shown in Fig. 9, in step S141A, the tire sensor 2 transmits a theft master code by broadcast communication to the vehicle-mounted devices 3 mounted on vehicles other than the vehicle itself, and then exits from this process. This theft master code is a data code including tire information of the vehicle itself. For example, as shown in Fig. 10, the theft master code includes data such as a theft master ID, ID information for identifying the tire sensor 2, the wheel position where the tire sensor 2 is attached, the tire air pressure, and the remaining sensor battery charge of the tire sensor 2.

[0069] In response to this, the on-board device 3 of the other vehicle performs the theft tracking process shown in Fig. 11 so as to be able to receive the theft master code. The theft tracking process shown in Fig. 11 is executed periodically or irregularly by the on-board device 3 of the other vehicle.

[0070] 11, the on-board device 3 of the other vehicle determines whether or not it has received a theft master code in step S141B. If it receives the theft master code, the on-board device 3 of the other vehicle notifies the tire theft information to the service center 73 outside the vehicle 10 in step S142B. The tire theft information is information that includes the tire information of the vehicle itself excluding the theft master ID, as well as the location and time (e.g., timestamp) at which the theft master code was received.

[0071] The service center 73 identifies the user of the wheels 10a-10d based on the tire theft information, and notifies the user terminal 75 of the user that the wheels 10a-10d have been stolen. The service center 73 may be configured to notify a security company or the police by a security system that the wheels 10a-10d have been stolen.

[0072] 4, if it is determined in the determination process of step S130 that the second theft flag is OFF, the tire sensor 2 executes a tire change / rotation detection process in step S150. This detection process will be described with reference to FIG.

[0073] 12, the tire sensor 2 reads various information in step S151. Specifically, the tire sensor 2 reads information related to acceleration changes from the acceleration sensor 22. In addition, the tire sensor 2 reads, via the in-vehicle device 3, on / off information of the ignition switch IG, door information including the door locked and unlocked states, and the like.

[0074] In step S152, the tire sensor 2 determines whether or not the vehicle 10 is in a stopped state. This determination process is similar to the determination process in step S102 in Fig. 5, and therefore a description thereof will be omitted.

[0075] If the vehicle 10 is not stopped but is moving, the tire sensor 2 skips the subsequent processes and exits from this process. On the other hand, if the vehicle 10 is not stopped, the tire sensor 2 determines in step S153 whether the doors are locked or the ignition switch IG is turned on.

[0076] If the result of this determination process shows that the doors of the vehicle 10 are locked and the ignition switch IG is off (i.e., the vehicle is in a "parked" state), the tire sensor 2 skips the subsequent processes and exits from this process. On the other hand, if the doors of the vehicle 10 are unlocked or the ignition switch IG is off (i.e., the vehicle is in a "parked" state), the tire sensor 2 proceeds to step S154. In step S154, the tire sensor 2 determines whether or not a predetermined acceleration change has been detected by the acceleration sensor 22. The predetermined acceleration change is set to, for example, the fluctuation range of the detection value of the acceleration sensor 22 that occurs when changing tires.

[0077] If the determination result in step S154 is an affirmative determination (YES), it means that a predetermined acceleration change has been detected by the acceleration sensor 22 with the vehicle 10 in a stopped state, the doors unlocked, or the ignition switch IG in an on state (i.e., the vehicle is stopped). In this case, it is highly likely that a tire change or tire rotation has been performed. Therefore, in step S155, the tire sensor 2 turns on a tire change flag, which indicates that a tire change or rotation may have been performed, and notifies the vehicle-mounted device 3 of this information before exiting this process.

[0078] When the on-board device 3 detects that the tire change flag is on, it executes a corresponding process such as tire change, etc. Hereinafter, the corresponding process such as tire change executed by the vehicle-mounted device 3 will be described with reference to FIG.

[0079] 13, in step S200, the vehicle-mounted device 3 determines whether the vehicle 10 is in a traveling state. Specifically, the vehicle-mounted device 3 determines that the vehicle 10 is in a traveling state when the vehicle speed is, for example, 5 km / h or more, and determines that the vehicle 10 is in a stopped state when the vehicle speed is less than 5 km / h.

[0080] When the vehicle 10 is in a traveling state, in step S210, the vehicle-mounted device 3 determines whether or not rotation of all the wheels 10a-10d pre-registered in the vehicle-mounted device 3 has been detected. This determination process can be performed, for example, by matching the ID information acquired from each tire sensor 2 with pre-registered ID information and detecting the rotation of the wheels 10a-10d based on the acceleration information acquired from each tire sensor 2.

[0081] If any of the pre-registered wheels 10a to 10d is not detected, it is assumed that a tire change has been performed. Therefore, if any of the pre-registered wheels 10a to 10d is not detected, the vehicle-mounted device 3 determines that a tire change has been performed and executes an automatic ID registration process to automatically register the tire ID in step S220.

[0082] On the other hand, if all pre-registered wheels 10a-10d are detected, it is considered that no tire change has occurred, but there is a possibility that the tires have been rotated. Therefore, in step S230, the tire sensor 2 determines that no tire change has occurred, and performs auto-location to automatically detect the positions of the wheels 10a-10b to which the tire sensor 2 is attached.

[0083] The wheel monitoring system described above determines the theft of the wheels 10a-10d by the tire sensor 2. That is, when the vehicle 10 is parked and a predetermined change in acceleration is detected by the acceleration sensor 22, the tire sensor 2 determines that the wheels 10a-10d have been stolen. In this manner, if the tire sensor 2 is configured to determine the theft of the wheels 10a-10d based on the detection result of the acceleration sensor 22, it is possible to detect the theft of the wheels 10a-10d without increasing the frequency of information transmission by the tire sensor 2. Therefore, it is possible to detect the theft of the wheels 10a-10d while suppressing power consumption due to information transmission by the tire sensor 2.

[0084] In addition, the wheel monitoring system can provide the following effects.

[0085] (1) The tire sensor 2 includes a tire radio 24 capable of bidirectional communication with the vehicle-mounted device 3. When the tire monitoring unit 23a detects the theft of the wheels 10a-10d, it transmits a theft signal indicating that the wheels 10a-10d have been stolen to the vehicle-mounted device 3 via the tire radio 24. When the vehicle-mounted device 3 receives the theft signal from the tire sensor 2, it notifies the theft of the wheels 10a-10d using a notification unit provided in the vehicle 10. In this way, if the theft of the wheels 10a-10d is notified from the vehicle 10 when the theft of the wheels 10a-10d is detected, it becomes easier for the user to quickly take action against the theft of the wheels 10a-10d (for example, to report to the police, a security company, etc.).

[0086] (2) When the vehicle-mounted device 3 receives the theft signal, it transmits a response signal to the tire sensor 2 in response to the theft signal. If the tire sensor 2 does not receive a response signal from the vehicle-mounted device 3 after transmitting the theft signal, it transmits a theft master code including the tire information of the vehicle to the vehicle-mounted device 3 mounted on another vehicle other than the vehicle. Then, when the vehicle-mounted device 3 mounted on the other vehicle receives the theft master code, it notifies the service center 73 outside the vehicle 10 of tire theft information including the position and time when the theft master code was received in addition to the tire information. In this way, even after the wheels 10a to 10d of the vehicle are taken away by theft, the stolen tires of the vehicle can be tracked based on the tire theft information notified to the service center 73. This is effective as a measure to prevent the theft of the wheels 10a to 10d.

[0087] (3) Specifically, as shown in Fig. 14, when the vehicle 10 is in a parked state and the acceleration sensor 22 detects a change in acceleration, the tire sensor 2 determines that the wheels 10a-10d have been stolen. Also, when the vehicle 10 is in a stopped state and the acceleration sensor 22 detects a change in acceleration, the tire sensor 2 determines that the tires may have been rotated or replaced. This makes it possible to distinguish between wheel theft and intentional movement of the wheels 10a-10d, such as tire rotation or replacement, and improves the accuracy of detecting the theft of the wheels 10a-10d.

[0088] (4) Furthermore, if the communication with the in-vehicle device 3 is interrupted while the vehicle 10 is in a parked state, the tire monitoring unit 23a of the tire sensor 2 determines that the wheels 10a to 10d have been stolen.

[0089] If the wheels 10a-10d are stolen and taken away to a position away from the body 11 of the vehicle 10, communication between the tire sensor 2 and the in-vehicle device 3 will be cut off. Therefore, the tire sensor 2 can determine whether the wheels 10a-10d have been stolen based on the success or failure of communication between the in-vehicle device 3 and the tire sensor 2. In such a case of determining whether the wheels 10a-10d have been stolen, there is no need to increase the frequency of information transmission from the tire sensor 2. Therefore, it is possible to detect the theft of the wheels 10a-10d while suppressing power consumption due to information transmission from the tire sensor 2.

[0090] (5) When the tire monitoring unit 23a of the tire sensor 2 detects the theft of the wheels 10a-10d, it transmits a theft master code including the tire information of the vehicle to the vehicle-mounted device 3 mounted on another vehicle other than the vehicle. Then, when the vehicle-mounted device 3 mounted on the other vehicle receives the theft master code, it notifies the service center 73 outside the vehicle 10 of tire theft information including the position and time when the theft master code was received in addition to the tire information. In this way, even after the wheels 10a-10d of the vehicle are taken away by theft, the stolen wheels 10a-10d of the vehicle can be tracked based on the tire theft information notified to the service center 73. This is effective as a measure to prevent theft of the wheels 10a-10d.

[0091] (6) When the vehicle 10 is traveling and the rotation of any of the pre-registered wheels 10a-10d is not detected, the vehicle-mounted device 3 determines that a tire change has been performed. Also, when the vehicle 10 is traveling and the rotation of all the pre-registered wheels 10a-10d is detected, the vehicle-mounted device 3 determines that a tire change has not been performed. This allows tire change to be detected appropriately. This allows, for example, the timing to perform automatic ID registration of the tire sensor 2, etc. to be appropriately grasped.

[0092] (Modification) The tire sensor 2 of the above embodiment is adapted to read various information including the traveling speed of the vehicle 10, the door state, and the on / off state of the ignition switch IG from the in-vehicle device 3 when performing the theft detection process or the tire change / rotation detection process. Then, based on the various information read from the in-vehicle device 3, the tire sensor 2 determines whether the state of the vehicle 10 is "parked state", "stopped state", or "traveling state", and then performs the detection process for theft, tire change, etc.

[0093] In such a case, the tire sensor 2 needs to frequently receive information from the vehicle-mounted device 3, and the information reception may consume a lot of power in the tire sensor 2. In addition, an increase in various determination processes on the tire sensor 2 side also causes an increase in the power consumption of the tire sensor 2.

[0094] Here, in the theft detection process and tire change / rotation detection process, it is sufficient if the vehicle 10 can be identified as being in a "parked state", a "stopped state", or a "driving state". Note that the "parked state" is, for example, a state in which the vehicle 10 is stopped, the doors are locked, and the ignition switch is turned off. Also, the "stopped state" is a state in which the vehicle 10 is stopped, the doors are unlocked, or the ignition switch is turned off.

[0095] The vehicle-mounted device 3 can determine whether the state of the vehicle 10 is a "parked state" or not based on the traveling speed of the vehicle 10, the state of the doors of the vehicle 10, and the on / off state of the ignition switch IG. In view of this, it is desirable that the vehicle-mounted device 3 determines whether the state of the vehicle 10 is a "parked state", a "stopped state", or a "traveling state", and when the state of the vehicle 10 changes, the vehicle-mounted device 3 notifies the tire sensor 2 of the determination result (synchronization of the vehicle state). For example, it is desirable that the vehicle-mounted device 3 determines whether the state of the vehicle 10 is a parked state or a stopped state based on the traveling speed of the vehicle 10, the state of the doors of the vehicle 10, and the on / off state of the ignition switch IG, and transmits the determination result to the tire sensor 2. According to this, it is sufficient that the tire sensor 2 receives information from the vehicle-mounted device 3 only once each time the state of the vehicle 10 changes, so that the power consumption of the tire sensor 2 can be sufficiently suppressed.

[0096] (Other embodiments) Representative embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments and can be modified in various ways, for example, as described below.

[0097] In the above embodiment, an example was shown in which theft detection of the wheels 10a-10d is performed based on the detection result by the acceleration sensor 22 in the parked state and the success or failure of communication between the tire sensor 2 and the in-vehicle device 3 in the parked state, but the present invention is not limited to this. The theft detection of the wheels 10a-10d may be performed based on either the detection result by the acceleration sensor 22 in the parked state or the success or failure of communication between the tire sensor 2 and the in-vehicle device 3 in the parked state.

[0098] As in the above-described embodiment, it is desirable for the wheel monitoring system to perform detection processing such as tire change in addition to the theft detection processing, but this is not limited thereto, and for example, the system may be configured to perform only one of the theft detection processing and the tire change detection processing.

[0099] In the above embodiment, when the vehicle-mounted device 3 receives a theft signal from the tire sensor 2, it uses a notification unit provided in the vehicle 10 to notify the theft of the wheels 10a-10d, but is not limited to this. When the vehicle-mounted device 3 receives a theft signal from the tire sensor 2, it may notify a service center 73 or the like outside the vehicle 10.

[0100] In the above embodiment, in the stopped state, the door-locked state and the ignition switch IG are in the off state are defined as the "parked state", and the ignition switch IG is in the on state or the door is in the unlocked state are defined as the "parked state", but this is not limited thereto. The "parked state" is a state in which the driver is away from the vehicle 10 and the vehicle 10 cannot immediately transition to a running state. The "parked state" is a state in which the vehicle 10 can immediately transition to a running state. For this reason, for example, in the stopped state, a state in which the electronic key of the vehicle 10 cannot be detected by the vehicle-mounted device 3 may be defined as the "parked state", and a state in which the electronic key can be detected by the vehicle-mounted device 3 may be defined as the "parked state".

[0101] The tire sensor 2 and the vehicle-mounted device 3 in the above-described embodiment are configured to be capable of bidirectional communication based on the BLE communication method, but may be configured to be capable of bidirectional communication based on a communication method other than BLE.

[0102] In the above-described embodiment, an example was given of the wheel monitoring system of the present disclosure being applied to a vehicle 10 having four wheels 10a to 10d, but the wheel monitoring system of the present disclosure can also be similarly applied to a vehicle 10 having a greater number of wheels.

[0103] In the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where it is particularly expressly stated that they are essential or where they are clearly considered to be essential in principle.

[0104] In the above-described embodiments, when numerical values ​​such as the number, values, amounts, ranges, etc. of components of the embodiments are mentioned, they are not limited to the specific numbers unless it is specifically stated as required or unless it is clearly limited to a specific number in principle.

[0105] In the above-described embodiments, when referring to the shapes, positional relationships, etc. of components, etc., there is no limitation to those shapes, positional relationships, etc., unless specifically stated or in principle limited to a specific shape, positional relationship, etc.

[0106] In the above-described embodiment, when it is described that external environment information (e.g., outside air temperature) of the vehicle 10 is acquired from a sensor, it is also possible to eliminate the sensor and receive the external environment information from a server or cloud external to the vehicle 10. Alternatively, it is also possible to eliminate the sensor and acquire related information related to the external environment information from a server or cloud external to the vehicle 10, and estimate the external environment information from the acquired related information.

[0107] The control unit and the method of the present disclosure may be implemented in a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. The control unit and the method of the present disclosure may be implemented in a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. The control unit and the method of the present disclosure may be implemented in one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. The computer program may also be stored in a computer-readable non-transitory tangible recording medium as instructions executed by a computer. [Explanation of symbols]

[0108] 10 Vehicles 11 Body 2 Tire Sensor 22 Acceleration Sensor 23a Tire Monitoring Section 24 Tire Radio 3 Onboard equipment

Claims

1. A wheel monitoring system applied to a vehicle (10) having a body (11) and a plurality of wheels (10a to 10d) including tires attached thereto, a tire sensor (2) including an acceleration sensor (22) provided on the wheel and outputting an acceleration that changes with the rotation of the wheel; An on-board device (3) provided on the vehicle body, The tire sensor and the on-board device are configured to be able to communicate bidirectionally, the on-board device determines whether the state of the vehicle is a parked state, a stopped state, or a moving state based on the traveling speed of the vehicle, the state of the doors of the vehicle, and an on / off state of an ignition switch of the vehicle, and transmits information including the determination result to the tire sensor; The tire sensor identifies the current state of the vehicle based on the information notified from the onboard device, and determines whether the vehicle has been stolen, the tires have been rotated, or the tires have been replaced based on a combination of the identified vehicle state and the sensor output of the acceleration sensor.

2. The vehicle-mounted device includes: When the traveling speed is less than a predetermined value, the vehicle doors are locked, and the ignition switch is off, the vehicle is determined to be in the parked state; determining that the vehicle is in the stopped state when the traveling speed is less than the predetermined value, the ignition switch is on, or the vehicle doors are unlocked, indicating a door unlocked state; 2. The wheel monitoring system according to claim 1, wherein the vehicle is determined to be in the running state when the running speed is equal to or greater than the predetermined value and the ignition switch indicates an on state.

3. 3. The wheel monitoring system according to claim 1, wherein the tire sensor determines that the wheel has been stolen when a predetermined change in acceleration is detected by the acceleration sensor while the vehicle is in the parked state.

4. 3. The wheel monitoring system according to claim 1, wherein the tire sensor determines that the tire may have been rotated or replaced when a predetermined change in acceleration is detected by the acceleration sensor while the vehicle is stopped.

5. The tire sensor includes: When a predetermined acceleration change is detected by the acceleration sensor in the parked state, it is determined that the wheel has been stolen, 3. The wheel monitoring system according to claim 1, wherein when the acceleration sensor detects a change in acceleration while the vehicle is stopped, it is determined that there is a possibility that the tires have been rotated or replaced.

6. The vehicle-mounted device includes: determining that a tire change has been performed when rotation of any of the pre-registered wheels is not detected in the running state; 6. The wheel monitoring system according to claim 5, wherein when rotation of all of the wheels registered in advance is detected in the running state, it is determined that the tire change has not been carried out.

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