JP2023163958A - Tire auto-location system and tire auto-location method - Google Patents

Abstract

To provide a tire auto-location system and a tire auto-location method which can save electric power of a power supply of a tire communication instrument.SOLUTION: A first processing part 28 makes tire communication instruments 4 respectively execute peak detection using output of an acceleration detecting part 11 that rotates in synchronization with a tire 3, by transmitting trigger radio waves Str for position determination, from an initiator 6 in which ranges where radio waves reach are different between axle units to the tire communication instruments 4. A second processing part 29 obtains measurement information Sk measured based on timings of reception of the trigger radio waves Str and of the peak detection in the tire communication instruments 4, by radio communication from each of the tire communication instruments 4. A third processing part 30 determines coordination of the axles 24 arranged in a longitudinal direction of a vehicle body with each of the tire communication instruments 4, on the basis of the measurement information Sk obtained from each of the tire communication instruments 4.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tire autolocation system and a tire autolocation method used in a TPMS (Tire Pressure Monitoring System).

BACKGROUND ART Conventionally, as disclosed in Patent Document 1, in a tire pressure monitoring system, a tire autolocation system that determines which electronic box is attached to which axle wheel aligned in the longitudinal direction of a vehicle body is well known. The electronic box is a communication device that detects the air pressure in the wheels and sends the air pressure information to the vehicle body. An electronic box is attached to each wheel so that it rotates synchronously with the wheel.

In the case of Patent Document 1, the electronic box detects its own rotational position based on wheel rotation based on the output of a built-in acceleration sensor. The electronic box also receives radio waves transmitted from the vehicle's central transceiver module. Based on the relationship between the rotational position of the electronic box when it receives radio waves from the central transceiver module and the received signal strength when it receives radio waves from the central transceiver module, which electronic box is attached to the wheel of which axle is determined. Determine whether there is one.

JP 2019-73274 Publication

In the case of Patent Document 1, the tire communication device measures, for example, the received signal strength of radio waves transmitted from the central transmitting/receiving module, detects the rotational position based on the output of an acceleration sensor, and measures the measured received signal strength and rotational position from the central transmitting/receiving module. It is necessary to perform various processing such as sending data to For this reason, there has been a concern that the electronic box consumes a large amount of power. In particular, since the power source of the electronic box is a battery, it is necessary to save power in order to enable long-term use.

A tire autolocation system that solves the above problem transmits tire air pressure information from a tire communication device attached to each tire of a vehicle, receives the air pressure information with a receiver on the vehicle body, and determines the tire air pressure. This is a configuration used in a tire pressure monitoring system to be monitored, and by transmitting a position determination trigger radio wave to a plurality of the tire communication devices from an initiator that forms a communication area where radio waves reach different ranges for each axle, a first processing unit that causes each of the tire communication devices to perform peak detection using the output of an acceleration detection unit that rotates in synchronization with the tire; and a timing of receiving the trigger radio wave and detecting the peak in the tire communication device; a second processing unit that wirelessly acquires measurement information from each of the tire communication devices; and a second processing unit that wirelessly acquires measurement information from each of the tire communication devices; and a third processing unit that determines the correspondence with the axles arranged in the direction.

A tire autolocation method that solves the above problem transmits tire air pressure information from a tire communication device attached to each tire of a vehicle, receives the air pressure information with a receiver on the vehicle body, and determines the tire air pressure. A method used in a tire pressure monitoring system to monitor, in which a trigger radio wave for position determination is transmitted to a plurality of tire communication devices from an initiator that forms a communication area where radio waves reach different ranges for each axle, causing each of the tire communication devices to perform peak detection using the output of an acceleration detection unit that rotates in synchronization with the tire; and measurement in the tire communication device based on the reception of the trigger radio wave and the timing of the peak detection. the measurement information obtained from each of the tire communication devices is obtained wirelessly from each of the tire communication devices; and based on the measurement information obtained from each of the tire communication devices, communication between each of the tire communication devices and the axles arranged in the longitudinal direction of the vehicle body is performed. The tire pressure monitoring system is caused to determine the correspondence.

INDUSTRIAL APPLICATION This invention can save the power supply of a tire communication device.

FIG. 1 is a configuration diagram of a tire autolocation system according to an embodiment. 1 is a schematic diagram showing an axle configuration of a vehicle. It is an output waveform diagram of the acceleration detection part which a tire communication device has. FIG. 3 is a communication area diagram of a first initiator. It is a communication area diagram of a 2nd initiator. It is a timing chart when determining correspondence between a tire and a tire communication device. (a) and (b) are distribution charts of determination times for each communication device ID. It is a block diagram of the receiver in another example. (a) and (b) are explanatory diagrams showing how to adjust the area of the initiator.

An embodiment of the present disclosure will be described below.
(Overview of tire pressure monitoring system 1)
As shown in FIG. 1, the vehicle 2 includes a tire pressure monitoring system (TPMS) 1 that monitors the air pressure of each tire 3. As shown in FIG. The tire pressure monitoring system 1 includes a tire communication device 4 that measures the tire pressure in the tire 3 and wirelessly transmits the tire pressure information Spr. The tire pressure monitoring system 1 of this example uses a method in which the tire communication device 4 transmits the tire pressure information Spr by itself at a prescribed timing, or transmits the tire pressure information Spr in response to a radio wave from an initiator 6 provided on the vehicle body 5. Either method is acceptable.

A tire communication device 4 is attached to each tire 3. The tire communication device 4 is, for example, a tire mount sensor embedded inside the tire 3 or a tire valve attached to a tire plug.

The tire communication device 4 includes a communication device control section 9 that controls the operation of the tire communication device 4. In the communication device control unit 9, a communication device ID, which is a unique ID given to each tire communication device 4, is written in a memory (not shown).

The tire communication device 4 includes a pressure detection section 10 that detects the air pressure of the tire 3, and an acceleration detection section 11 that detects acceleration (for example, gravitational acceleration) generated in the tire communication device 4. The pressure detection unit 10 is, for example, a pressure sensor. The acceleration detection unit 11 is, for example, an acceleration sensor (G sensor). The communication device control section 9 receives signals from the pressure detection section 10 and the acceleration detection section 11.

The tire communication device 4 includes an antenna 12 that performs communication. The antenna 12 includes, for example, a receiving antenna 12a that receives radio waves and a transmitting antenna 12b that transmits radio waves. The receiving antenna 12a receives, for example, radio waves in the LF (Low Frequency) band. The transmitting antenna 12b transmits radio waves in the UHF (Ultra High Frequency) band, for example. The communication device control unit 9 performs wireless communication via the receiving antenna 12a and the transmitting antenna 12b.

The tire communication device 4 transmits the air pressure information Spr from the transmission antenna 12b at a predetermined timing. The air pressure information Spr includes, for example, pressure information detected by the pressure detection section 10 and a communication device ID registered in the memory of the communication device control section 9. The tire communication device 4 transmits the air pressure information Spr, for example, at a predetermined timing or when receiving an instruction to transmit radio waves from the initiator 6.

The tire air pressure monitoring system 1 includes a receiver 14 on the vehicle body 5 that receives air pressure information Spr transmitted from the tire communication device 4 and monitors the air pressure of each tire 3. The receiver 14 includes an antenna 15 that receives the air pressure information Spr transmitted from the tire communication device 4, and a monitoring control unit 16 that monitors the air pressure of the tire 3 based on the received air pressure information Spr. In the memory 17 of the monitoring control unit 16, the communication device ID and the tire position are registered in a linked manner. That is, which communication device ID corresponds to which mounting position of the tire 3 is registered in the memory 17. The antenna 15 receives radio waves in the UHF band, for example.

When the monitoring control unit 16 receives the air pressure information Spr transmitted from the tire communication device 4 through the antenna 15, it checks the communication device ID included in the air pressure information Spr. If the communication device ID is registered in the memory 17, the monitoring control unit 16 checks the air pressure information Spr included in the same radio wave. If the tire air pressure is below the threshold, the monitoring control unit 16 displays on the display unit 18 that the tire air pressure is low, in association with the tire position. The monitoring control unit 16 notifies the driver of whether or not there is an abnormality in the air pressure of each tire 3 by executing this air pressure check for each received air pressure information Spr.

(Example of vehicle 2)
As shown in FIG. 2, the vehicle 2 is, for example, a load carrier 21. The transport vehicle 21 is, for example, a truck or a trailer. The transport vehicle 21 includes a drive section 22 having a driver's seat and a traveling drive source, and a cargo section 23 towed by the drive section 22.

The vehicle 2 has a plurality of axles 24 with tires 3 attached to both ends of the axles. In this example, one axle 24 is provided in the drive section 22, and a plurality of axles 24 are provided in the cargo section 23, for example. The axle 24 of this example includes a first axle 24a provided in the drive section 22 so as to follow the steering wheel operation, a second axle 24b, a third axle 24c, a fourth axle 24d provided in the cargo section 23, and and a fifth axle 24e. One tire 3 is attached to each of the first axle 24a and the second axle 24b at both ends of the axle. Two tires 3 are attached to each of the third axle 24c to the fifth axle 24e at both ends of the axle.

(Overview of Tire Auto Location System 27)
As shown in FIG. 1, the tire pressure monitoring system 1 includes a function (tire autolocation system 27) that automatically registers the association between the communication device ID and the tire position. The tire autolocation system 27 of this example automatically registers which axle 24 of the plurality of axles 24 each tire communication device 4 is attached to.

As shown in FIG. 3, the acceleration detection unit 11 detects gravitational acceleration according to the rotational position of the tire 3. Specifically, the acceleration detection unit 11 outputs acceleration data Dg in the form of a trigonometric function (for example, a sine wave) in which one rotation of the tire is one cycle. For example, the acceleration data Dg takes a value within the range of "-1G to +1G" as a gravity dependence component. The acceleration data Dg detects a peak value of "-1G" each time the tire is located at the apex of the rotation path (the 12 o'clock point on the clock in the figure).

As shown in FIG. 2, the initiator 6 is placed at a position to transmit radio waves to a set of axles 24 arranged in front and behind each other. The initiator 6 of this example includes a first initiator 6a that transmits radio waves to the tire communication device 4 attached to each tire 3 of the first axle 24a and the second axle 24b, and each tire of the third axle 24c to the fifth axle 24e. and a second initiator 6b that transmits radio waves to the tire communication device 4 attached to the tire. For example, the initiator 6 transmits radio waves in the LF band, thereby forming a communication area E in which the radio waves can reach the tire communication device 4 serving as the communication partner.

As shown in FIG. 4, the first initiator 6a has a communication area Ea that includes a rear region of the tire 3 attached to the first axle 24a and a front region of the tire 3 attached to the second axle 24b. is set to . That is, the communication area Ea of the first initiator 6a is set so that the radio waves reach different areas for the tires 3 attached to the first axle 24a and the tires 3 attached to the second axle 24b. There is.

As shown in FIG. 5, the second initiator 6b is attached to the rear region of the tire 3 attached to the third axle 24c, the entire area of the tire 3 attached to the fourth axle 24d, and the second initiator 6b attached to the fifth axle 24e. The communication area Eb is set to include an area near the front of the tire 3. That is, the communication area Eb of the second initiator 6b is for each of the tires 3 attached to the third axle 24c, the tires 3 attached to the fourth axle 24d, and the tires 3 attached to the fifth axle 24e. The radio waves are set to reach different areas.

As shown in FIG. 1, the tire autolocation system 27 includes a first processing unit 28 that transmits a position determination trigger radio wave Str from the initiator 6 to the tire communication device 4 to execute the tire autolocation operation. The first processing section 28 is provided in the monitoring control section 16 of the receiver 14. The first processing unit 28 causes the tire communication device 4 to receive a trigger radio wave Str for position determination from the initiator 6, which has a different range of radio waves for each axle, and uses the output of the acceleration detection unit 11, which rotates in synchronization with the tire 3, to generate a peak signal. Each tire communication device 4 is caused to perform the detection.

The first processing unit 28 transmits a trigger radio wave Str from the first initiator 6a to each tire communication device 4 of the tire 3 attached to the first axle 24a and the second axle 24b. The first processing unit 28 transmits a trigger radio wave Str from the second initiator 6b to each tire communication device 4 of the tire 3 attached to the third axle 24c to the fifth axle 24e. The trigger radio wave Str transmitted from the first initiator 6a and the trigger radio wave Str transmitted from the second initiator 6b may be transmitted simultaneously or with a time difference.

As shown in FIG. 6, upon receiving the trigger radio wave Str through the receiving antenna 12a, the tire communication device 4 executes rotation peak detection. The tire communication device 4 measures, for example, a measured value Tx (first measured value T1 in this example) representing the time required from receiving the trigger radio wave Str to starting peak frequency detection. The tire communication device 4 measures, for example, a measurement value Tx (second measurement value T2 in this example) representing the time required from the start of peak frequency detection until the peak is detected a specified number of times.

When the measurement is completed, the tire communication device 4 transmits the measurement information Sk to the receiver 14. The measurement information Sk is transmitted from the tire communication device 4 using UHF band radio waves, for example. The measurement information Sk is information measured by the tire communication device 4 based on the reception of the trigger radio wave Str and the timing of peak detection. Specifically, the measurement information Sk is information including a measurement value Tx (first measurement value T1 and second measurement value T2) and a communication device ID registered in the tire communication device 4.

As shown in FIG. 1, the tire autolocation system 27 includes a second processing unit 29 that acquires measurement information Sk measured by the tire communication devices 4 from each of the tire communication devices 4. The second processing section 29 is provided in the monitoring control section 16 of the receiver 14. For example, when the measurement information Sk transmitted from the tire communication device 4 is received by the antenna 15 of the receiver 14, the second processing unit 29 takes in the measurement information Sk. The second processing unit 29 acquires measurement information Sk from each of the tire communication devices 4 that are present in the vehicle 2 .

The tire autolocation system 27 includes a third processing unit 30 that determines which tire 3 the tire communication device 4 is attached to. The third processing section 30 is provided in the monitoring control section 16 of the receiver 14. The third processing unit 30 determines the correspondence between each of the tire communication devices 4 and the axles 24 arranged in the longitudinal direction of the vehicle body, based on the measurement information Sk acquired from each of the tire communication devices 4.

In addition, it is preferable that the third processing unit 30 also determines which of the left and right wheels of each axle 24 the tire communication device 4 is attached to. This auto-location of the left and right wheels is also preferably performed based on the measurement information Sk acquired from the tire communication device 4. In this way, the third processing unit 30 may perform the processing based on the measured value Tx in the measurement information Sk, for example.

(Action of embodiment)
Next, the operation of the tire autolocation system 27 (tire autolocation method) of this embodiment will be explained.

As shown in FIG. 6, when it is time to execute tire autolocation, the first processing unit 28 transmits a trigger radio wave Str from the initiator 6 to the tire communication device 4 to start tire autolocation (time t1). The trigger radio wave Str is, for example, an LF band signal that includes a bit signal that instructs the tire communication device 4 to start measuring the measured value Tx. The trigger radio wave Str in this example is transmitted from each of the first initiator 6a and the second initiator 6b toward the tire communication device 4 forming the pair.

When the tire communication device 4 receives the trigger radio wave Str through the reception antenna 12a, it starts measuring time by using its own timer, for example. That is, the tire communication device 4 starts monitoring the acceleration data Dg of the acceleration detection section 11 at the same time as starting time measurement. Then, the tire communication device 4 measures the time required from receiving the trigger radio wave Str to detecting the first peak, that is, the first measurement value T1.

Note that after the tire communication device 4 receives the trigger radio wave Str, the peak that occurs first may be missed (time t2). At this time, the peak that occurs after one rotation of the tire after the release is detected as the first peak (time t3). When the tire communication device 4 detects the first peak, it starts detecting the number of peaks.

After starting the peak number detection, the tire communication device 4 measures the time required from starting the peak number detection until detecting the peak a predetermined number of times, that is, the second measurement value T2 (time t4). The number of peak detections (the number of tire rotations) is set as a predetermined value in the tire autolocation system 27. Both the tire communication device 4 and the receiver 14 know the number of peak detections. In this example, the number of times of peak detection is set to "3 times", for example.

After measuring the second measurement value T2, the tire communication device 4 transmits the measurement information Sk obtained by the measurement from the transmission antenna 12b using UHF band radio waves (time t5). The measurement information Sk in this example includes, for example, a first measurement value T1, a second measurement value T2, and a communication device ID. The measurement information Sk is transmitted after a delay time Td has elapsed, for example, in order to prevent radio wave interference with other tire communication devices 4. The delay time Td is, for example, a random value that differs for each tire communication device 4.

When the receiver 14 receives the measurement information Sk through the antenna 15, the second processing section 29 takes in this measurement information Sk. Then, the third processing section 30 calculates the period Tr per rotation of the tire based on the measurement information Sk taken in by the second processing section 29. The period Tr is determined by the formula "Tr=T2/number of peak detections" using, for example, the second measurement value T2 in the measurement information Sk and the constant number of peak detections (number of tire rotations: 3 in this example). It is calculated by

The third processing unit 30 uses the calculated period Tr and the first measurement value T1 to determine a determination time T1, which is the time required from when the tire communication device 4 receives the trigger radio wave Str to when the first peak is detected. 'Seek.' In this example, if the first measured value T1 is equal to or less than the period Tr, the first measured value T1 is taken in as the determination time T1'. That is, when the first measured value T1 is less than or equal to the period Tr, the first measured value T1 is directly acquired as the determination time T1' because no peak is missed.

On the other hand, if the first measured value T1 exceeds the period Tr, the third processing unit 30 calculates the determination time T1' by performing an operation using the period Tr and the first measured value T1. That is, since a missed peak has occurred, the determination time T1' is determined by a calculation that can offset this missed peak. This operation may be, for example, subtraction or division. The subtraction is, for example, an operation of subtracting the period Tr from the first measurement value T1, and the remainder is obtained as the determination time T1'. In the division, for example, the first measured value T1 is divided by the period Tr, and the remainder is determined as the determination time T1'.

Note that the series of processes from time t1 to time t5 shown in FIG. 6 may be executed multiple times. That is, a series of processes including the following [1] to [3] may be executed multiple times.
[1] Sending a trigger radio wave Str from the initiator 6 to each tire communication device 4 [2] Making each tire communication device 4 execute peak rotation detection and transmitting measurement information Sk to the receiver 14 [3] Measurement Determining the determination time T1' from the information Sk The third processing unit 30 determines the correspondence between the tire communication device 4 and the axle 24 based on the plurality of determination times T1'.

As shown in FIG. 4, when the first initiator 6a transmits the trigger radio wave Str, the tire communication device 4 attached to the first axle 24a reaches the peak position relatively quickly after receiving the trigger radio wave Str. , there is a tendency for the determination time T1' to become shorter. On the other hand, when the first initiator 6a transmits the trigger radio wave Str, in the case of the tire communication device 4 attached to the second axle 24b, the distance from receiving the trigger radio wave Str to reaching the peak position is long, so the determination is made. There is a tendency for time T1' to become longer.

Therefore, as shown in FIG. 7A, for example, when the determination time T1' of "ID1" is distributed in a short time period (ta, tb, tc, td), the third processing unit 30 ” is determined to be the tire communication device 4 of the tire 3 attached to the first axle 24a. Further, as shown in FIG. 7B, for example, when the determination time T1' of "ID2" is distributed over a long time period (te, tf, tg, th), the third processing unit 30 is determined to be the tire communication device 4 of the tire 3 attached to the second axle 24b.

As shown in FIG. 5, in the case of the tire communication device 4 attached to the third axle 24c, the determination time T1' tends to be short because it reaches the peak position relatively quickly after receiving the trigger radio wave Str. In the case of the tire communication device 4 attached to the fourth axle 24d, since the trigger radio wave Str is received at any rotational position, the determination time T1' tends to vary. In the case of the tire communication device 4 attached to the fifth axle 24e, since the distance from receiving the trigger radio wave Str to reaching the peak position is long, the determination time T1' tends to be long.

For this reason, the third processing unit 30 selects the IDs that are distributed in the time period where the determination time T1' is short, among the communication device IDs that received a response when the second initiator 6b transmitted the trigger radio wave Str, to the third axle. It is determined that it is the tire communication device 4 of the tire 3 attached to the tire 24c. Similarly, the third processing unit 30 determines that the ID whose determination time T1' varies is the tire communication device 4 of the tire 3 attached to the fourth axle 24d, and distributes the ID in which the determination time T1' is long. ID is determined to be the tire communication device 4 of the tire 3 attached to the fifth axle 24e.

Note that the third processing unit 30 also determines, for example, which tire 3 on the left or right of each axle 24 has the tire communication device 4 attached to it. This left/right determination may be performed, for example, using the rotational speed of each tire 3 during curve travel. Specifically, when traveling on a curve, each tire 3 has a unique rotational speed on the left and right sides, so the period Tr determined for each tire communication device 4 also takes a value related to the rotational speed of the tire 3. Therefore, the third processing unit 30 may determine which tire communication device 4 is attached to the left or right tire 3 based on the magnitude of the value of the period Tr.

When the position determination is finalized, the third processing unit 30 writes the position determination result into the memory 17. That is, the third processing unit 30 writes the combination of the mounting position of the tire 3 and the communication device ID of the tire communication device 4 into the memory 17. With the above steps, tire autolocation is completed. Note that the completion of tire autolocation may be notified to the driver by, for example, displaying a message to that effect on the display unit 18.

(Effects of embodiment)
According to the tire autolocation system 27 (tire autolocation method) of the above embodiment, the following effects can be obtained.

(1) The tire pressure monitoring system 1 transmits tire pressure information Spr from the tire communication device 4 attached to each tire 3 of the vehicle 2, and receives the tire pressure information Spr by the receiver 14 of the vehicle body 5. Monitor the air pressure of tires 3. A tire autolocation system 27 is used in this tire pressure monitoring system 1. The tire autolocation system 27 includes a first processing section 28, a second processing section 29, and a third processing section 30. The first processing unit 28 transmits a trigger radio wave Str for position determination to a plurality of tire communication devices 4 from an initiator 6 forming a communication area E in which radio waves reach different ranges for each axle, so that the first processing unit 28 rotates synchronously with the tire 3. Each tire communication device 4 is caused to perform peak detection using the output of the acceleration detection section 11. The second processing unit 29 wirelessly acquires measurement information Sk measured by the tire communication device 4 based on the reception of the trigger radio wave Str and the peak detection timing from each of the tire communication devices 4. The third processing unit 30 determines the correspondence between each of the tire communication devices 4 and the axles 24 arranged in the longitudinal direction of the vehicle body, based on the measurement information Sk acquired from each of the tire communication devices 4.

According to this configuration, when executing the tire autolocation of the tire communication device 4, the tire communication device 4 obtains the measurement information Sk based on the reception of the trigger radio wave Str and the timing of peak detection, and calculates the measurement information Sk. It is sufficient to simply execute the process of transmitting the data to the receiver 14 of the vehicle body 5. Specifically, when the tire communication device 4 performs tire autolocation, it is not necessary, for example, to measure the received signal strength in the tire communication device 4 or to transmit this measurement data to the receiver 14. Therefore, it is possible to reduce the processing load on the tire communication device 4. Therefore, power consumption of the tire communication device 4 can be reduced.

(2) The measurement information Sk includes a first measurement value T1 representing the time required from the time when the tire communication device 4 receives the trigger radio wave Str until starting the peak number detection, and a and a second measurement value T2 representing the time required to detect the specified number of times. According to this configuration, it is possible to perform a calculation using the first measurement value T1 and the second measurement value T2, and determine the correspondence between the tire communication device 4 and the axle 24 from the calculation result. Therefore, the association between the tire communication device 4 and the axle 24 can be executed with high accuracy.

(3) The third processing unit 30 determines the cycle Tr per tire rotation based on the second measurement value T2, and determines whether the tire communication device 4 receives the trigger radio wave Str based on the cycle Tr and the first measurement value T1. The determination time T1', which is the time required from the time when the first peak is detected until the first peak detection, is determined for each tire communication device 4, and based on the determination time T1' determined for each tire communication device 4, the tire communication device 4 and the axle 24 are associated. Determine.

According to this configuration, the tire communication device 4 generates the trigger radio wave Str using the period Tr obtained from the second measurement value T2 obtained from the tire communication device 4 and the first measurement value T1 obtained from the tire communication device 4. The time required from reception until the first peak is detected can be determined with high accuracy as the determination time T1'. Therefore, the association between the tire communication device 4 and the axle 24 can be executed with high accuracy using the highly reliable determination time T1'.

(4) Sending a trigger radio wave Str from the initiator 6 to each tire communication device 4, causing each tire communication device 4 to perform peak frequency detection and transmitting measurement information Sk to the receiver 14, and measurement information Sk A series of processes including determining the determination time T1' from is executed multiple times. The third processing unit 30 determines the correspondence between the tire communication device 4 and the axle 24 based on the plurality of determination times T1'. According to this configuration, it is possible to associate the tire communication device 4 and the axle 24 based on the trends of the plurality of determination times T1'. Therefore, even if the determination time T1' suddenly changes, it is possible to obtain a determination result that is not affected by this change. Therefore, it contributes to improving the accuracy of determining the mounting position of the tire communication device 4.

(5) Each tire communication device 4 transmits measurement information Sk to the vehicle body 5 with a time difference (difference in delay time Td) with respect to other tire communication devices 4. According to this configuration, when transmitting the measurement information Sk from each tire communication device 4 to the vehicle body 5, the measurement information Sk does not need to collide with each other.

(Other embodiments)
Note that this embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

- As shown in FIG. 8, the tire autolocation system 27 may include an area adjustment unit 35 that can adjust the communication area E formed by the initiator 6. The area adjustment section 35 is provided in the monitoring control section 16, for example. The area adjustment unit 35 adjusts the communication area E formed by the initiator 6, for example, by checking the response of each tire communication device 4 to the radio waves transmitted from the initiator 6. Note that the adjustment of the communication area E may be performed either during tire autolocation or during non-tire autolocation.

Specifically, as shown in FIG. 9A, if the communication area E is too narrow, for example, when the trigger radio wave Str is transmitted, a response from the tire communication device 4 is not received often. The area adjustment unit 35 of this example gradually expands the communication area E if the number of responses from both the front and rear tire communication devices 4 when transmitting the trigger radio wave Str is equal to or less than a specified number. Then, when a sufficient number of responses are obtained from each of the front and rear tire communication devices 4, the adjustment is stopped. Thereby, the communication area E of the initiator 6 is optimized.

Further, as shown in FIG. 9(b), for example, if the communication area E is too large, when the trigger radio wave Str is transmitted and a response is obtained from the tire communication device 4, the determination time T1' is determined in any tire communication device 4. will vary. When the area adjustment unit 35 of this example detects that the determination time T1' varies in any of the tire communication devices 4, it gradually narrows the communication area E, and when a predetermined tendency is obtained in the determination time T1', the area adjustment unit 35 gradually narrows the communication area E. , the adjustment stops there. Thereby, the communication area E of the initiator 6 is optimized.

In this way, the area adjustment unit 35 adjusts the communication area E formed by the initiator 6 by checking the response of each tire communication device 4 to the radio waves transmitted from the initiator 6. According to this configuration, it is possible to optimize the communication area E formed by the initiator 6, so when the trigger radio wave Str is transmitted from the initiator 6, it is possible to make the tire communication device 4 respond accurately. becomes. Therefore, it contributes to improving the accuracy of determining the mounting position of the tire communication device 4.

- The measurement information Sk may include only the first measurement value T1. That is, the measurement information Sk may include a measurement value Tx representing the time required from when the tire communication device 4 receives the trigger radio wave Str until it starts detecting the number of peaks. This is because, for example, if there is no missed peak, it is possible to determine the correspondence between the tire 3 and the tire communication device 4 using only the first measured value T1. According to this configuration, when the tire communication device 4 performs tire autolocation, it is only necessary to measure the time required from when the tire communication device 4 receives the trigger radio wave Str to when it starts detecting the number of peaks. Therefore, it further contributes to power saving of the power source of the tire communication device 4.

- The delay time Td may be instructed by the initiator 6 to each tire communication device 4. In this case, when tire autolocation is started, an ID provision request is sent from the initiator 6 in order to collect the communication device ID of the tire communication device 4 attached to each tire 3. When each of the tire communication devices 4 receives the ID provision request at the receiving antenna 12a, each of the tire communication devices 4 transmits the communication device ID registered in itself toward the receiver 14 from the transmitting antenna 12b. In addition, when each tire communication device 4 transmits the communication device ID, it is preferable to transmit the communication device ID with a time difference so that the signals do not interfere.

After collecting the communication device ID, the first processing unit 28 transmits a position determination trigger radio wave Str from the initiator 6. In this case, the trigger radio wave Str includes, for example, an instruction for the tire communication device 4 to start measuring the measured value Tx, and delay information representing a waiting time when transmitting the measured measurement information Sk. The delay information is, for example, information specifying which communication device ID and how long the waiting time should be. In this way, each tire communication device 4 may be instructed to specify an individual delay time Td.

- The peak is not limited to the highest point in the tire rotation direction (the 12 o'clock position on a clock). For example, the peak may be the lowest point in the tire rotation direction (the 6 o'clock position on a clock), or may be any other prescribed position.

- The initiator 6 may be arranged separately for the left wheel of the front and rear axles and for the right wheel of the front and rear axles. In this case, even if the radio waves from the initiator 6 do not reach both the left and right wheels of the front and rear axles, this can be handled.

- The determination logic for tire autolocation may not take into account the possibility of missing peaks.
- Tire autolocation may be executed, for example, when the vehicle 2 starts traveling. Alternatively, tire autolocation may be performed a certain period of time after the start of travel.

- Sending a trigger radio wave Str from the initiator 6 to each tire communication device 4, causing each tire communication device 4 to perform peak rotation detection and transmitting measurement information Sk to the receiver 14, and determining from the measurement information Sk. A series of processes including determining time T1' may be executed only once.

- The air pressure information Spr and the measurement information Sk may be signals using the same format.
- The vehicle 2 is not limited to the transport vehicle 21, and may be, for example, a passenger car or a bus.
- The first processing section 28, the second processing section 29, and the third processing section 30 may be configured by [1] one or more processors that operate according to a computer program (software), or [2] such The processor may be configured by a combination of a processor and one or more dedicated hardware circuits such as an application specific integrated circuit (ASIC) that executes at least some of the various types of processing. A processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to perform processing. Memory (computer-readable media) includes any available media that can be accessed by a general purpose or special purpose computer. Alternatively, instead of a computer including the processor, a processing circuit configured with one or more dedicated hardware circuits that executes all of the various processes may be used.

- The first processing section 28, the second processing section 29, and the third processing section 30 may be constructed from independent processors, or may be constructed from processors whose functions are partially shared. In this way, the first processing section 28, the second processing section 29, and the third processing section 30 are not limited to independent functional blocks, but may be composed of one functional block, or may have partially shared functions. It may be composed of blocks.

- Although the present disclosure has been described based on examples, it is understood that the present disclosure is not limited to the examples or structures. The present disclosure also includes various modifications and equivalent modifications. In addition, various combinations and configurations, as well as other combinations and configurations that include only one, more, or fewer elements, are within the scope and scope of the present disclosure.

DESCRIPTION OF SYMBOLS 1... Tire pressure monitoring system, 2... Vehicle, 3... Tire, 4... Tire communication device, 5... Vehicle body, 6... Initiator, 11... Acceleration detection part, 14... Receiver, 24... Axle, 27... Tire autolocation system , 28...first processing section, 29...second processing section, 30...third processing section, Spr...air pressure information, Str...trigger radio wave, E...communication area, Sk...measurement information, Tx...measured value, T1...th 1 measurement value, T2...second measurement value, T1'...judgment time, Tr...period.

Claims (8)

A tire used in a tire pressure monitoring system that monitors the tire pressure by transmitting tire pressure information from a tire communication device attached to each tire of a vehicle, and receiving the tire pressure information by a receiver on the vehicle body. An autolocation system,
By transmitting trigger radio waves for position determination to a plurality of tire communication devices from an initiator that forms a communication area in which radio waves reach different ranges for each axle, peak detection using the output of an acceleration detection unit that rotates in synchronization with the tires is performed. a first processing unit that causes each of the tire communication devices to perform detection;
a second processing unit that wirelessly acquires measurement information measured in the tire communication device based on the reception of the trigger radio wave and the timing of the peak detection from each of the tire communication devices;
A tire autolocation system comprising: a third processing unit that determines correspondence between each of the tire communication devices and axles arranged in the longitudinal direction of the vehicle body based on the measurement information acquired from each of the tire communication devices. The measurement information includes a first measurement value representing the time required from when the tire communication device receives the trigger radio wave to when it starts detecting the number of peaks, and a predetermined number of times the peak has been detected since it started detecting the number of peaks. 2. The tire autolocation system of claim 1, further comprising: a second measurement value representative of the time taken to locate the tire. The third processing unit calculates a cycle per rotation of the tire based on the second measured value, and calculates the first cycle after the tire communication device receives the trigger radio wave based on the cycle and the first measured value. Claim 2: A determination time, which is the time required to detect the peak, is determined for each tire communication device, and a correspondence between the tire communication device and the axle is determined based on the determination time determined for each tire communication device. Tire autolocation system described in. transmitting the trigger radio wave from the initiator to each tire communication device; causing each tire communication device to perform peak frequency detection and transmitting the measurement information to the receiver; and determining the determination time from the measurement information. A series of processes, including determining , are executed multiple times,
The tire autolocation system according to claim 3, wherein the third processing unit determines the association between the tire communication device and the axle based on the plurality of determination times. The tire autolocation system according to claim 1, wherein the measurement information includes a measurement value representing the time required from when the tire communication device receives the trigger radio wave until it starts detecting the number of peaks. The tire autolocation system according to claim 1, wherein each of the tire communication devices transmits the measurement information to the vehicle body with a time difference with respect to other tire communication devices. The tire autolocation system according to claim 1, further comprising an area adjustment unit that adjusts the communication area formed by the initiator by checking a response of each of the tire communication devices to the radio waves transmitted from the initiator. A tire used in a tire pressure monitoring system that monitors the tire pressure by transmitting tire pressure information from a tire communication device attached to each tire of a vehicle, and receiving the tire pressure information by a receiver on the vehicle body. An autolocation method,
By transmitting trigger radio waves for position determination to a plurality of tire communication devices from an initiator that forms a communication area in which radio waves reach different ranges for each axle, peak detection using the output of an acceleration detection unit that rotates in synchronization with the tires is performed. causing each of the tire communication devices to perform detection;
wirelessly acquiring measurement information measured by the tire communication device based on the reception of the trigger radio wave and the timing of the peak detection from each of the tire communication devices;
A tire autolocation method that causes the tire pressure monitoring system to determine, based on the measurement information acquired from each of the tire communication devices, a correspondence between each of the tire communication devices and axles arranged in the longitudinal direction of the vehicle body. .

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