JP2008308168A - Wheel information processing apparatus and wheel information processing method - Google Patents

Abstract

When a plurality of sensors are provided on a wheel and sensor outputs are transmitted to a vehicle body side communication device, transmission signals from the plurality of sensors interfere with each other.
A vehicle body side communication device 200 transmits a request signal to a wheel side sensor 31 provided in a valve 24 of a wheel 22 and a tire side sensor 32 embedded in a tire tread 28. When the wheel side sensor 31 and the tire side sensor 32 receive a request signal from the vehicle body side communication device 200, the wheel side sensor 31 and the tire side sensor 32 transmit a response signal to the vehicle body side communication device 200. Different patterns.
[Selection] Figure 2

Description

  The present invention relates to a technique for processing wheel information, and more particularly, to a wheel information processing apparatus and a wheel information processing method for receiving and processing wheel information from a wheel side communication device.

  In order for the vehicle to travel safely, it is essential to keep the wheels in a normal state. If the vehicle is run for a long time in a state where the tire is at a low pressure or a high temperature, the reliability of the tire is impaired, and an undesirable phenomenon is caused in some cases. Therefore, there is a demand for a technique for appropriately monitoring the air pressure, temperature and other conditions of individual tires and warning the driver early when an abnormality is detected.

Patent Document 1 discloses a tire pressure alarm system including a wheel side transmitter that transmits tire pressure information and a vehicle body side receiver that receives tire pressure information from a wheel side communication device.
Japanese Utility Model Laid-Open No. 5-13802

  In the alarm system as disclosed in Patent Document 1, it is assumed that there is one wheel side communication device on the wheel side, and when there are a plurality of wheel side communication devices on the wheel, there is a problem of interference. Occurs. In order to grasp the state of the wheel, various types of sensor information such as air pressure and temperature are required as wheel information, and sensor information of different locations such as tires and wheels is required even when detecting the temperature. Therefore, a number of sensors are provided on one wheel, and a plurality of communication devices that transmit the output of the sensor are also provided, and transmission signals from a plurality of wheel side communication devices are received without interference, and wheel information is received. There is a need for processing technology.

  Further, in the tire pressure warning system of Patent Document 1, the transmission of the signal by the wheel side communication device is performed with a different prime number period for each wheel. In this method, when the number of wheel side communication devices increases, the transmission is performed. The difference in the period increases, and the amount of information that can be acquired varies.

  This invention is made | formed in view of such a point, The objective is to provide the wheel information processing technique which can receive wheel information reliably from several wheel side communication apparatus.

  One embodiment of the present invention relates to a wheel information processing apparatus. This device includes a plurality of wheel side communication devices provided on one wheel and a vehicle body side communication device that communicates with the plurality of wheel side communication devices, and each of the plurality of wheel side communication devices has a different identification number. The vehicle body side communication device transmits a request signal including the identification number to the plurality of wheel side communication devices, and the plurality of wheel side communication devices include their identification numbers in the received request signals. Send a reply signal. According to this structure, the vehicle body side communication apparatus can specify the wheel side communication apparatus of a communication destination, and can acquire wheel information from the specified wheel side communication apparatus.

  Another aspect of the present invention relates to a wheel information processing method. This method receives and processes wheel information from a plurality of wheel side communication devices provided on one wheel, and identifies the wheel side communication device from a vehicle body side communication device to the plurality of wheel side communication devices. Transmitting a request signal including a number, and receiving a reply signal from the wheel side communication device that has received the request signal including its own identification number.

  Still another aspect of the present invention also relates to a wheel information processing apparatus. This device includes a plurality of wheel side communication devices provided on one wheel and a vehicle body side communication device that communicates with at least one of the plurality of wheel side communication devices. A first wheel side communication device that performs communication, and a second wheel side communication device that indirectly communicates with the vehicle body side communication device using the first wheel side communication device as a repeater.

  According to the wheel information processing apparatus and the wheel information processing method of the present invention, it is possible to reliably acquire necessary wheel information while avoiding signal interference in the vehicle body side communication device.

Embodiment 1
FIG. 1 shows an overall configuration of a vehicle 10 including a wheel information processing apparatus according to the first embodiment. The vehicle 10 includes four wheels 20a to 20d and a vehicle body 12. Sensors 30a to 30d for detecting the wheel state quantities of the wheels 20a to 20d and information on the detected wheel state quantities (hereinafter simply referred to as "wheel information") are transmitted to the vehicle body 12 to the wheels 20a to 20d. Communication devices 40a to 40d and communication antennas 50a to 50d are provided. The vehicle body 12 includes vehicle body side communication devices 200a to 200d that receive wheel information from the respective wheels 20a to 20d, communication antennas 210a to 210d, and an electronic control device (hereinafter, "ECU" ”64, an initialization switch 68, an alarm buzzer 70, and a warning lamp 72. Hereinafter, when the configuration is described without distinguishing each wheel, the symbols a to d that distinguish each wheel are omitted.

  Each wheel 20 is provided with a plurality of sensors 30, and the output value of each sensor is sent to the communicator 40 and transmitted from the antenna 50 to the vehicle body side communicator 200 by radio. The communication device 40 and the antenna 50 may be built in the sensor 30.

  The vehicle body side communication device 200 receives the wheel information from the communication device 40 via the antenna 210 provided in the vicinity of the wheel 20 and sends the received wheel information to the ECU 64. The ECU 64 grasps the state of the wheel 20 based on the wheel information received from the vehicle body side communication device 200. The ECU 64 turns on the warning lamp 72 when the tire temperature of the wheel 20 exceeds a predetermined value, or the tire air pressure of the wheel 20 falls below the predetermined value, or causes the buzzer 70 to sound a warning sound. To the driver.

  The ECU 64 includes a storage unit that stores mounting positions and identification information of the plurality of sensors 30 provided on each wheel 20. The ECU 64 causes the vehicle body side communication device 200 to receive the identification information of each of the plurality of sensors 30 provided on each wheel 20 when the engine is started, and updates the identification information registered in the storage unit as appropriate. The initialization switch 68 is pressed by the driver when the wheel 20 is rotated or replaced. When the initialization switch 68 is pressed, the ECU 64 updates the mounting position and identification information of the sensor 30 registered in the storage unit based on the wheel information that the vehicle body side communication device 200 subsequently receives from each wheel 20.

  FIG. 2 is a cross-sectional view of the wheel 20, and in this cross-sectional view, an example of the mounting location and configuration of the plurality of sensors 30 provided on each wheel 20 described in FIG. 1 is shown. The wheel 20 includes a tire 21, a wheel 22, and a rim 26. A wheel side sensor 31 is integrally assembled with a valve 24 of the wheel 22, and a tire side sensor 32 is embedded in a tire tread 28. The wheel-side sensor 31 is a high-performance sensor equipped with an air pressure sensor that detects the air pressure of the tire 21 and a temperature sensor that detects the temperature of air in the tire 21, and the tire-side sensor 32 is a temperature of the tire tread 28. It is a temperature sensor that detects Each of the wheel-side sensor 31 and the tire-side sensor 32 is an example of a sensor 30 provided on the wheel 20 shown in FIG. In this example, the wheel 20 is provided with two sensors 30 in the form of a wheel-side sensor 31 and a tire-side sensor 32, but is not limited to a mode in which the sensor 30 is provided on each of the wheel 20 and the tire side. There is also a form in which a plurality of sensors 30 are provided only on the wheel side of the wheel 20 or only on the tire side. The wheel side sensor 31 and the tire side sensor 32 incorporate the communication device 40 and the antenna 50 described with reference to FIG. 1, and communicate wirelessly with the vehicle body side communication device 200 provided on the vehicle body 12 via the antenna 210.

  The vehicle body side communication device 200 transmits a request signal to the wheel side sensor 31 and the tire side sensor 32, and the wheel side sensor 31 and the tire side sensor 32 receive the request signal from the vehicle body side communication device 200, and A reply is appropriately sent to the communication device 200. Communication between the vehicle body side communication device 200 and the wheel side sensor 31 and communication between the vehicle body side communication device 200 and the tire side sensor 32 are bidirectional, and a low frequency band is used.

  In wireless communication using a low frequency band, the communication distance is short and there is less risk of interference with other communications, so signals are sent and received without identifying information for identifying the communication source and destination. Is common. Therefore, when the wheel side sensor 31 and the tire side sensor 32 perform short-distance wireless communication with the vehicle body side communication device 200 provided in the vicinity of the wheel as in the present embodiment, the communication signal is distinguished by the identification information. If the transmission timing of the transmission signal of the wheel side sensor 31 and the transmission signal of the tire side sensor 32 overlap, there will be a problem of interference.

  Even though the communication distance is short, interference between the four wheels can occur with a low probability. That is, the transmission signal of the sensor 30 provided on the left front wheel may be received by the vehicle body side communication device 200 provided near the right front wheel. However, even when there is interference between the wheels, it is possible to identify signals received from other wheels due to differences in the number of responses to requests and differences in received signal strength. Therefore, below, the communication procedure which the vehicle body side communication apparatus 200, the wheel side sensor 31, and the tire side sensor 32 implement in order to prevent interference in the same wheel is demonstrated.

  FIGS. 3A to 3C are diagrams for explaining the communication procedure of the vehicle body side communication device 200, the wheel side sensor 31, and the tire side sensor 32. The vehicle body side communication device 200 specifies the communication destination by identification information. Indicates when to do. As shown in FIG. 3A, the vehicle body side communication device 200 transmits a request signal 100 designating identification information of the wheel side sensor 31 to the wheel side sensor 31 and the tire side sensor 32 at time t0. The wheel side sensor 31 and the tire side sensor 32 receive the request signal 100 of the vehicle body side communication device 200 at time t1. Since the wheel side sensor 31 includes its own identification information in the received request signal, the wheel side sensor 31 transmits a reply signal 110 to the vehicle body side communication device 200 as shown in FIG. On the other hand, the tire side sensor 32 does not respond at all as shown in FIG. 3C because the identification information included in the received request signal is not its own identification information.

  In this way, the vehicle body side communication device 200 adds the identification information of any of the plurality of sensors 30 provided on the same wheel to the request signal 100 and performs broadcast communication with the plurality of sensors 30, thereby communicating with the communication destination. Sensor 30 can be selected, and interference does not occur.

  FIGS. 4A to 4C show a communication procedure when the transmission start timings of reply signals to the request signal 100 of the vehicle body side communication device 200 are different. As shown in FIG. 4A, the vehicle body side communication device 200 transmits the request signal 100 to the wheel side sensor 31 and the tire side sensor 32 at time t0. In this case, the vehicle body side communication device 200 does not select either the wheel side sensor 31 or the tire side sensor 32 and transmits the request signal 100, but transmits the request signal 100 to either sensor. Request transmission of detected value.

  The wheel side sensor 31 and the tire side sensor 32 receive the request signal 100 of the vehicle body side communication device 200 at time t1. As shown in FIG. 4B, the wheel side sensor 31 sets the transmission start timing of the reply signal 110 to a time point after the time T1 from the reception time t1 of the request signal 100. On the other hand, as shown in FIG. 4C, the tire side sensor 32 sets the transmission start timing of the reply signal 120 to a time point T2 after the reception time t1 of the request signal 100, and the reply signal of the wheel side sensor 31. 110 is delayed from the transmission start timing.

  Due to the deviation of the transmission start timing, the transmission timing of the reply signal 110 of the wheel side sensor 31 and the reply signal 120 of the tire side sensor 32 do not overlap, and interference is avoided. The vehicle body side communication device 200 can reliably receive both the reply signal 110 of the wheel side sensor 31 and the reply signal 120 of the tire side sensor 32 without interference, and the transmission start of the two reply signals 110 and 120 is started. The two reply signals 110 and 120 can be distinguished from the difference between the timings T1 and T2.

  FIGS. 5A to 5C show a communication procedure when the transmission cycle of the reply signal to the request signal 100 of the vehicle body side communication device 200 is different. As shown in FIG. 5A, the vehicle body side communication device 200 transmits the request signal 100 to the wheel side sensor 31 and the tire side sensor 32 at time t0. The wheel side sensor 31 and the tire side sensor 32 receive the request signal 100 of the vehicle body side communication device 200 at time t1. The wheel side sensor 31 transmits a reply signal 110 at a transmission cycle S1 shown in FIG. 5B, and the tire side sensor 32 transmits a reply signal 120 at a transmission cycle S2 shown in FIG.

  Since there is a time difference in signal transmission as shown in FIGS. 5B and 5C due to the difference in the transmission periods S1 and S2 of the reply signals 110 and 120 of the wheel side sensor 31 and the tire side sensor 32, two replies are made. Interference of the signals 110 and 120 is avoided. The vehicle body side communication device 200 can distinguish the return signals 110 and 120 of the wheel side sensor 31 and the tire side sensor 32 based on the respective transmission cycles S1 and S2.

  FIGS. 6A to 6C show a communication procedure when the transmission interval of the reply signal to the request signal 100 of the vehicle body side communication device 200 is random. As shown in FIG. 6A, the vehicle body side communication device 200 transmits the request signal 100 to the wheel side sensor 31 and the tire side sensor 32 at time t0. The wheel side sensor 31 and the tire side sensor 32 receive the request signal 100 of the vehicle body side communication device 200 at time t1. The wheel side sensor 31 transmits the reply signal 110 a plurality of times at random transmission intervals R1 and R2 shown in FIG. 6B, and the tire side sensor 32 receives the random transmission intervals R3 and R4 shown in FIG. 6C. The reply signal 120 is transmitted a plurality of times.

  Since the transmission intervals of the reply signals 110 and 120 of the wheel side sensor 31 and the tire side sensor 32 are random, even if the transmission timings of the two reply signals 110 and 120 may coincide by chance, the two reply signals 110 and 120 Is transmitted a plurality of times, as shown in FIGS. 6B and 6C, the transmission intervals R1 and R2 of the return signal 110 of the wheel-side sensor 31 and the transmission interval R3 of the return signal 120 of the tire-side sensor 32. Because of the difference between R4 and R4, the transmission times of the two reply signals 110 and 120 transmitted a plurality of times are shifted, and there is no overlap in transmission timing, so that interference is avoided. The reply signal 110 from the wheel side sensor 31 and the reply signal 120 from the tire side sensor 32 have different data formats such as different bit lengths. The vehicle body side communicator 200 uses the reply signal 110 from the wheel side sensor 31 and the tire side. The return signal 120 of the sensor 32 can be distinguished by the difference in data format.

  As described above, when the wheel side sensor 31 and the tire side sensor 32 change the transmission patterns of the return signals 110 and 120, the vehicle body side communication device 200 causes the two return signals 110 and 120 to interfere with each other. The two reply signals 110 and 120 can be distinguished from the difference in transmission pattern. The wheel side sensor 31 and the tire side sensor 32 do not need to add sensor identification information to the transmission signal, and can prevent interference by a simple method.

Embodiment 2
The second embodiment has the same configuration as that of the first embodiment, but the communication procedure between the vehicle body side communication device 200 and the plurality of sensors 30 is different from that of the first embodiment. FIG. 7 is a diagram for explaining a state in which the wheel side sensor 31 and the tire side sensor 32 according to the second embodiment communicate with the vehicle body side communication device 200. In the present embodiment, the tire side sensor 32 adds the identification information of the tire side sensor 32 to the output signal of the sensor and transmits it to the wheel side sensor 31 wirelessly without directly communicating with the vehicle body side communication device 200. . The wheel side sensor 31 transfers the received output signal of the tire side sensor 32 to the vehicle body side communication device 200. Further, the wheel side sensor 31 adds the identification information of the wheel side sensor 31 to the output signal of its own sensor and directly transmits it to the vehicle body side communication device 200. The vehicle body side communication device 200 outputs the output signal of the wheel side sensor 31 directly received from the wheel side sensor 31 and the output signal of the tire side sensor 32 received indirectly via the wheel side sensor 31 as output signals. It is distinguished by the identification information added to.

  FIG. 8 is a diagram illustrating a communication procedure of the vehicle body side communication device 200, the wheel side sensor 31, and the tire side sensor 32. The vehicle body side communication device 200 transmits a request signal to the wheel side sensor 31 (S10). The wheel side sensor 31 transmits a reply signal with its own identification information added to the request signal to the vehicle body side communication device 200 (S12).

  The wheel side sensor 31 transfers the request signal from the vehicle body side communication device 200 to the tire side sensor 32 (S14). The tire side sensor 32 transmits a reply signal with its own identification information added thereto to the wheel side sensor 31 (S16). The wheel side sensor 31 transfers the received reply signal of the tire side sensor 32 to the vehicle body side communication device 200 (S18).

  In the above procedure, in step S12, the wheel side sensor 31 transmits its own reply signal to the vehicle body side communication device 200. As a modification, however, step S12 is omitted, and in step S18, the wheel side sensor 31 returns its own reply. You may make it transmit a signal to the vehicle body side communication apparatus 200 with the reply signal of the tire side sensor 32. FIG.

  In the present embodiment, since the wheel side sensor 31 functions as a communication repeater of the tire side sensor 32, the transmission timing of the return signal of the wheel side sensor 31 and the return signal of the tire side sensor 32 does not overlap, Does not occur. Since the tire-side sensor 32 performs short-range wireless communication with the wheel-side sensor 31, the communication distance is shorter and less power is required than when communicating with the vehicle-body side communication device 200 on the vehicle body 12 side. When the tire side sensor 32 is battery-driven, battery consumption can be suppressed.

  In step S16, the tire side sensor 32 transmits a reply signal to the wheel side sensor 31 by short-range wireless communication, but the transmission signal of the tire side sensor 32 arrives at the vehicle body side communication device 200 via the antenna 210. Therefore, in the vehicle body side communication device 200, there is a possibility that the transmission signal of the tire side sensor 32 and the transmission signal of the wheel side sensor 31 may interfere with each other. Therefore, as described in the first embodiment, the wheel-side sensor 31 and the tire-side sensor 32 may have different transmission patterns of the reply signals to avoid interference in the vehicle body-side communication device 200. . For example, if the tire side sensor 32 transmits a signal at a transmission frequency different from that of the wheel side sensor 31, the vehicle body side communication device 200 determines whether the received signal is a signal from the wheel side sensor 31 or from the tire side sensor 32. Can be identified.

  FIG. 9 is a diagram illustrating another communication mode of the vehicle body side communication device 200, the wheel side sensor 31, and the tire side sensor 32. In FIG. 7, the tire side sensor 32 and the wheel side sensor 31 are configured to perform two-way communication wirelessly. However, in FIG. 9, the tire side sensor 32 and the wheel side sensor 31 are connected by a connection line 33. In this configuration, 32 output signals are sent to the wheel-side sensor 31 by wire. The communication procedure is the same as in FIG. 8 except for the difference between the communication between the tire side sensor 32 and the wheel side sensor 31 being wired or wireless. In this embodiment, since the tire side sensor 32 does not need to include the communication device 40 and the antenna 50, the cost of the tire side sensor 32 can be suppressed. Since the tire side sensor 32 is discarded together with the tire 21 when the tire 21 is replaced, it is important to reduce the cost of the tire side sensor 32.

  The present invention has been described based on the embodiments. The above embodiments are exemplifications, and it is understood by those skilled in the art that various modifications thereof are also included in the scope of the present invention. Examples of such modifications are given.

  The wheel side communicator 40 may be a transponder in which power is supplied by radio waves from the vehicle body side communicator 200 or may be a battery-driven communicator with a built-in battery. In the above description, the wheel side communication device 40 and the vehicle body side communication device 200 are configured to perform bidirectional communication, and the communication device 40 transmits a reply signal in response to a request signal from the vehicle body side communication device 200. The wheel side communicator 40 has a transmission only function, and the vehicle body side communication apparatus 200 has a function of only reception. May be changed.

  In the first and second embodiments, the wheel side sensor 31 provided on the valve 24 of the wheel 22 and the tire side sensor 32 provided on the tire tread 28 have been described as examples of the plurality of sensors 30 provided on the wheel. This shows an example of the sensor mounting location, and the sensor may be provided at other locations, for example, the rim 26 of the wheel 22. The type of sensor is not limited to the air pressure sensor and the temperature sensor, and may be any type of sensor that detects the wheel state quantity, such as a speed sensor or an acceleration sensor.

  In the first and second embodiments, the vehicle body side communication device 200 distinguishes the reply signal from the wheel side sensor 31 and the reply signal from the tire side sensor 32 from the difference in the transmission start timing, transmission cycle, data format, identification information, and the like. However, when these cannot be distinguished, ECU64 analyzes the signal received by the vehicle body side communication apparatus 200, and discriminate | determines whether it is the signal of the wheel side sensor 31 or the signal of the tire side sensor 32. May be.

  For example, if the wheel side sensor 31 and the tire side sensor 32 are both temperature sensors, they have the same data format and cannot be distinguished in the data format, but the ECU 64 receives a temperature change after the initialization switch 68 is depressed. The received signal having the larger temperature rise can be determined as the signal from the tire side sensor 32 by observing from the generated signal. This is because the wheel-side sensor 31 detects the temperature of the air in the tire 21, whereas the tire-side sensor 32 detects the temperature of the tire tread 28, and the tire tread 28 increases in temperature during traveling. Because is big.

  In addition, when the acceleration sensor is provided on both the tire side and the wheel side, the acceleration sensor provided on the tire side outputs a higher frequency signal, so the ECU 64 analyzes the frequency of the received signal. The signal from the tire-side acceleration sensor or the wheel-side acceleration sensor can be identified.

  Thus, ECU64 can learn the mounting position of the some sensor 30 in a wheel by analyzing the wheel information which the vehicle body side communication apparatus 200 acquired, and can register it in a memory | storage part. The ECU 64 periodically analyzes wheel information such as when the engine is started to check the mounting state of the sensor 30, and if the mounting state changes, the registration data may be automatically reinitialized. Good. Further, when the vehicle body side communication device 200 transmits a request signal to the tire side sensor 32, when a reply signal including identification information different from the identification information already registered in the storage unit is received from the tire side sensor 32, The ECU 64 may determine that there has been a tire change or a tire rotation, and may automatically re-initialize the registration data.

It is a figure which shows the whole structure of the vehicle provided with the wheel information processing apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the mounting location of the some sensor provided in the tire of FIG. It is a figure explaining the procedure which the sensor designated by the request signal transmits a reply signal with respect to the request signal of the vehicle body side communication apparatus of FIG. It is a figure explaining the procedure in which a some sensor transmits a reply signal in different transmission start timing with respect to the request signal of the vehicle body side communication apparatus of FIG. It is a figure explaining the procedure in which a some sensor transmits a reply signal in different transmission periods with respect to the request signal of the vehicle body side communication apparatus of FIG. It is a figure explaining the procedure in which a some sensor transmits a reply signal with a random transmission interval with respect to the request signal of the vehicle body side communication apparatus of FIG. It is a figure explaining the communication form of the vehicle body side communication apparatus which concerns on Embodiment 2, and a some sensor. It is a figure explaining the communication procedure of the vehicle body side communication apparatus of FIG. 7, and a some sensor. It is a figure explaining another communication form of a body side communication machine and a plurality of sensors.

Explanation of symbols

  20 wheel, 30 sensor, 31 wheel side sensor, 32 tire side sensor, 40 communicator, 64 ECU, 68 initialization switch, 70 buzzer, 72 warning lamp, 100 request signal, 110, 120 reply signal, 200 vehicle body side communication device .

Claims (3)

In a wheel information processing apparatus provided with a plurality of wheel side communication devices provided on one wheel and a vehicle body side communication device that communicates with the plurality of wheel side communication devices,
Each of the plurality of wheel side communicators has a different identification number,
The vehicle body side communication device transmits a request signal including the identification number to the plurality of wheel side communication devices,
The wheel information processing apparatus, wherein the plurality of wheel side communication devices transmit a reply signal when the received request signal includes its own identification number. In a wheel information processing method for receiving and processing wheel information from a plurality of wheel side communication devices provided on one wheel,
Transmitting a request signal including an identification number of the wheel side communication device from the vehicle body side communication device to the plurality of wheel side communication devices;
Receiving a return signal from the wheel side communication device that has received the request signal including its own identification number. In a wheel information processing apparatus comprising a plurality of wheel side communication devices provided on one wheel and a vehicle body side communication device communicating with at least one of the plurality of wheel side communication devices,
A first wheel side communicator that directly communicates with the vehicle body side communicator;
A wheel information processing apparatus comprising: a second wheel side communication device that communicates indirectly with the vehicle body side communication device using the first wheel side communication device as a repeater.

Images