Communication system, vehicle unit and seat unit

Abstract

A communication system (1) comprising a seat unit (2) adapted to be mounted on a seat (4) of a vehicle and to receive a power supply from a battery (21) for operation, and a vehicle unit (3) adapted to wirelessly communicate with the seat unit (2), wherein the vehicle unit (3) comprises a determination section (311) configured to determine whether communication with the seat unit (2) is necessary, and a command transmission section (311) configured to transmit to the seat unit (2) a transmission command requesting the seat unit (2) to transmit information via an electronic device (SW1, SW2) mounted on the seat (4) during a period in which the determination section (311) determines that communication with the seat unit (2) is necessary, and wherein the seat unit (2) is configured to transmit the information via the electronic device (SW1, SW2) upon receipt of the transmission command.

Description

background

[0001] The present invention relates to a communication system and a vehicle unit and a seat unit used in the communication system. The communication unit includes the seat unit, which is mounted on a seat of a vehicle and powered by a power supply from a battery, and the vehicle unit, which wirelessly communicates with the seat unit.

[0002] A prior art signal receiving device performs infrared communication between a sliding seat and a vehicle and uses a battery as a power source on one side of a sliding seat, so that routing of a wire harness between the sliding seat and the vehicle is avoided (see, for example, JP 2013 - 67 322 A).

[0003] However, according to the signal receiving device described above, communication between the sliding seat and the vehicle is performed even during a period when communication with the sliding seat is not necessary. Therefore, battery depletion occurs quickly.

[0004] US 2009 / 0 259 369 A1 describes an intelligent child safety seat, or ICSS, comprising an electronic unit loaded with manufacturer-specific specifications for the ICSS, or ICSS data, configured to communicate at least one feature to vehicle systems via a common interface. The ICSS data supports the provision of seat installation instructions, the detection of potential incompatibilities, the detection of the presence of a child and the placement of the ICSS in the vehicle seat, the detection of misuse and improper reuse after a crash or after the expiration date, a check to determine if the ICSS is included in recall announcements, and several safety applications performed by vehicle systems. The electronic unit also includes at least one module consisting of an I / O module, a sensor module, and a device module.A communication interface between the ICSS and the vehicle can be implemented in top-tether arrangements.

[0005] DE 10 2018 205 976 A1 describes a vehicle detection system comprising an RFID reader unit, a detection device, and an ECU. The RFID reader unit transmits a transmission signal containing at least one power-supplying signal. The detection device includes a second antenna unit that transmits and receives a signal to and from the RFID reader unit, an RFID detection circuit that activates using the power-supplying signal included in the transmission signal received by the second antenna unit as drive power and outputs a detection signal to the second antenna unit, and a switching circuit that switches an electrical connection portion between the second antenna unit and the RFID detection circuit to a contact state or a non-contact state according to a condition inside the vehicle.The ECU determines the condition inside the vehicle based on the detection signal received by the RFID reader.

[0006] US 2013 / 0 300 555 A1 describes a seat belt reminder system that includes an on-board vehicle sensor to detect an occupant on a vehicle seat, and a buckle sensor to detect when a seat belt is engaged in a seat belt buckle. A control unit detects whether the buckle is engaged, and a wireless transmitter sends the buckle status to a remote receiver in the vehicle. The control unit and transmitter are powered by a battery that is separate from the vehicle's electrical system. The control unit, transmitter, and battery can be integrated with the occupant sensor. By providing a separate power supply for the control unit and transmitter, and providing a wireless connection to the receiver in the vehicle, the need for a wiring harness from the seat to the vehicle is eliminated.The seat belt reminder system can provide a long battery life by connecting the control unit and transmitter to the battery only when the seat is occupied. Summary

[0007] Representative aspects of the present invention provide a communication system suitable for extending battery life, a vehicle unit, and a seat unit.

[0008] According to one illustrative aspect of the invention, a communication system includes a seat unit configured to be mounted on a seat of a vehicle and receive a power supply from a battery for operation, and a vehicle unit configured to wirelessly communicate with the seat unit. The vehicle unit includes a determining section configured to determine whether communication with the seat unit is necessary, and a command transmitting section configured to transmit to the seat unit a transmission command requesting the seat unit to transmit information via an electronic device mounted on the seat during a period in which the determining section determines that communication with the seat unit is necessary.The seat unit is configured to transmit the information via the electronic device upon receipt of the transmission command.

[0009] According to another illustrative aspect of the invention, an in-vehicle unit is configured to wirelessly communicate with a seat unit mounted on a seat of a vehicle, the seat unit being configured to receive a power supply from a battery for operation. The in-vehicle unit includes a determining section configured to determine whether communication with the seat unit is necessary, and a command transmitting section configured to transmit to the seat unit a transmission command requesting the seat unit to transmit information via an electronic device mounted on the seat during a period in which the determining section determines that communication with the seat unit is necessary.

[0010] According to another illustrative aspect of the invention, a seat unit is configured to be mounted on a seat of a vehicle and receive a power supply from a battery for operation, wherein the seat unit is configured to wirelessly communicate with the above-described vehicle unit. The seat unit includes an information transmission section configured to transmit information via an electronic device upon receipt of the transmission command from the vehicle unit.

[0011] Other aspects and advantages of the invention will become apparent from the following description, figures and claims. Short description of the characters Fig. 1 is an illustrative diagram showing configurations of a vehicle unit and a seat unit constituting a communication system of the invention; Fig. 2 is a schematic configuration diagram of the Fig. 1 communication system; Fig. 3 is a detailed electrical configuration diagram of the Fig. 1 seat unit shown; Fig. 4 is a flowchart showing a processing procedure of the Fig. 1 represents the vehicle units shown; Fig. 5 is a flowchart showing a processing procedure of the Fig. 1 represents the seat unit shown; Fig. 6 is a schematic configuration diagram of a communication system of a reference example; Fig. 7A and Fig. 7B are flowcharts showing a processing method of a Fig. 6 represent the vehicle unit shown; and Fig. 8A and Fig. 8B are flowcharts showing the processing procedures of a Fig. 6 represent the seat unit shown. Detailed description

[0012] Hereinafter, exemplary embodiments of the present invention are described with reference to the figures.

[0013] As in Fig. 1, a communication system includes a seat unit 2 provided on a sliding seat (sliding seat) 4 (seat), and a vehicle unit 3 provided on a vehicle (vehicle body). The communication system 1 is a system that transmits information from the seat unit 2 to the vehicle unit 3 via an electronic device provided on the sliding seat 4.

[0014] The sliding seat 4 is mounted on a vehicle and mainly includes a seat cushion 41 and a seat back 42. With a rail 5 provided below the seat cushion 41, the sliding seat 4 is slidable along a front-rear direction of the vehicle.

[0015] A seat unit 2 is mounted on a sliding seat 4 and is powered by a battery 21. In the present embodiment, the battery 21 is constituted by a primary battery that cannot be recharged and is, for example, a battery that needs to be replaced regularly, such as at the time of vehicle inspections.

[0016] Furthermore, in the present embodiment, an example is described in which the seat unit is mounted on all the sliding seats 4 (driver's seat, front passenger's seat, and rear seats) mounted in a vehicle, and the invention is not limited thereto. The seat unit 2 may be mounted only on the sliding seat 4 serving as the driver's seat, or may be mounted only on the sliding seats 4 serving as the driver's seat and the front passenger's seat.

[0017] As in Fig. As shown in Figure 2, the seat unit 2 includes a seat switch SW1, a buckle switch (lock switch) SW2, a control section 22, and a power switch SW3. The seat switch SW1 is one of the electronic devices mounted on the sliding seat 4. The seat switch SW1 is arranged, for example, in the seat cushion 41, as shown in Figure 2. Fig. 1, is pressed to turn on when an occupant sits on the sliding seat 4, and is turned off when the occupant leaves the sliding seat 4. Seating of the occupant can be detected based on an on-off state of the seat switch SW1.

[0018] In the present embodiment, as shown in Fig. 3, the seat switch SW1 is provided in a power supply line between the battery 21 and the control section 22, which will be described later. In Fig. 3, a solid line indicates a power supply line, and a dashed line indicates a signal line. Seat unit 2 transmits on / off information of seat switch SW1 to vehicle unit 3.

[0019] The buckle switch SW2 is one of the electronic devices mounted on the sliding seat 4. The buckle switch SW2 is provided on a buckle (clasp) of a seat, as shown in Fig. 1, is turned on when a tongue thereof is inserted into the seat buckle and is turned off when the tongue is pulled out. A seat belt worn by the occupant can be detected based on the on-off state of the buckle switch SW2.

[0020] In the present embodiment, the seat switch SW1 and the buckle switch SW2 are described as examples of the electronic devices mounted on the sliding seat 4, and the invention is not limited thereto. For example, various sensors mounted on the sliding seat 4 may be the electronic devices.

[0021] The control section 22 acquires information about the electronic devices including the seat switch SW1 and the buckle switch SW2, and wirelessly transmits the acquired information to the vehicle unit 3. As shown in Fig. 2, the control section 22 includes a timer 222 and a wireless communication device 221 that performs and controls wireless communication (such as Bluetooth (registered trademark)) with the vehicle unit 3.

[0022] The wireless communication device 221 includes an outer portion and a substrate housed in the outer portion (neither of which is shown), and is provided on the substrate with an antenna AT1 and a wireless communication IC 221A with a microcomputer function (hereinafter abbreviated as "wireless communication IC 221A"). The wireless communication IC 221A is constituted by an IC constituting a communication portion that transmits and receives signals via the antenna AT1 and a microcomputer that controls the communication portion (neither of which is shown). On-off information about the seat switch SW1 and the buckle SW2 is supplied to the wireless communication IC 221A. The wireless communication IC 221A controls on-off of the power switch SW3.

[0023] The timer 222 starts taking a predetermined time period under the control of the wireless communication IC 221 and outputs an off signal to turn off the power switch SW3, which will be described later, when the taking of the predetermined time period is completed. As shown in Fig. 3, the power switch SW3 in the power supply line between the battery 21 and the control section 22 is connected in parallel with the seat switch SW1.

[0024] The vehicle unit 3 is arranged, for example, on an instrument panel of a vehicle, as in Fig. 1, and is operated upon receiving a power supply from a battery 7. The battery 7 is formed by a secondary battery and is charged by an alternator. As shown in Fig. As shown in Figure 2, the in-vehicle unit 3 is constituted by a wireless communication device 31. The wireless communication device 31 includes an outer portion and a substrate housed in the outer portion (neither of which is shown), and is provided on the substrate with an antenna AT2, a wireless communication IC 311 having a microcomputer function (hereinafter abbreviated as "wireless communication IC 311"), and a multiplex communication IC 312.

[0025] The wireless communication IC 311 is constituted by an IC that forms a communication section that receives and transmits signals via the antenna AT2, and a microcomputer that controls the communication section (neither of which is shown). The multiplex communication IC 312 is an IC for multiplexing communication (such as CAN and CXPI) with a body control module (BCM) 6. The BCM 6 is mounted on an instrument panel of a vehicle, receives information about electronic devices mounted on the sliding seat from the in-vehicle unit 3, and executes predetermined control. In the present embodiment, the BCM 6 receives an on-off signal of the seat switch SW1 and the buckle switch SW2 from the in-vehicle unit 3 and issues a warning when sitting is detected while the seat belt is not worn.

[0026] Operations of the communication system 1 with the configuration described above are described below with reference to the Fig. 4 and Fig. 5. First, the wireless communication IC 311 of the vehicle unit 3 (hereinafter also abbreviated as “vehicle unit 3”) functions as a determination section and determines whether an ignition (IG) switch is on and a speed of the vehicle is a predetermined value or greater (for example, 3 km / h or more) (steps S1 and S2 in Fig. 4). If the IG switch is on and the vehicle speed is 3 km / h or higher (Y in step S1 and Y in step S2), the in-vehicle unit 3 determines that communication with the seat unit 2 is necessary. Further, the wireless communication IC 311 of the in-vehicle unit 3 functions as a command transmission section and sequentially transmits to each seat unit 2 a transmission command requesting each seat unit 2 to transmit information about the electronic devices attached to the sliding seat (step S3).

[0027] Thereafter, upon receiving the information from each seat unit 2 (Y in step S4), the in-vehicle unit 3 controls the multiplex communication IC 312 to transmit the information received from the seat unit 2 to the BCM 6 (step S5). Next, the in-vehicle unit 3 waits to see if a specified time period or more has elapsed since the transmission command is transmitted (Y in step S6) and returns to step S1 again. Accordingly, the in-vehicle unit 3 transmits a transmission command to the seat unit 2 at an interval of the specified time period during a period in which the IG switch is on and the vehicle speed is equal to or above 3 km / h.On the other hand, if the vehicle unit 3 cannot receive the information from the seat unit 2 even if the predetermined time period or more has elapsed since the transmission command is transmitted (Y in step S7), the vehicle unit 3 immediately returns to step S1.

[0028] In the seat unit 2, the power switch SW3 is turned off in an initial state. Therefore, the seat switch SW1 and the power switch SW3 are also turned off during a period in which the occupant is not sitting on the sliding seat 4, and thus, power supply to the control section 22 is cut off. Thereafter, when the occupant is sitting on the sliding seat 4, the seat switch SW1 is turned on. Power is supplied to the control section 22 in response to the seat switch SW1 turning on, and the wireless communication IC 221A of the seat unit 2 (hereinafter simply abbreviated as "seat unit 2") performs an operation. When the power is turned on, the seat unit 2 turns on the first power switch SW3 (step S11 in Fig. 5).

[0029] Next, the seat unit 2 acquires on-off information of the seat switch SW1 (step S12). If the acquired on-off information is information indicating that the seat switch SW1 is on (Y in step S13), the seat unit 2 determines whether a transmission command has been received from the vehicle unit 3 (step S14). Upon receiving the transmission command (Y in step S14), the seat unit 2 acquires on-off information of the buckle switch SW2 (step S15).

[0030] Next, the wireless communication IC 221 on the seat unit 2 functions as an information transmission section to wirelessly transmit the on-off information of the seat switch SW1 and the buckle switch SW2 acquired in steps S12 and S15 to the vehicle unit 3 (step S16) and returns to step S12. The on-off information of the seat switch SW1 transmitted in step S16 is information indicating that the seat switch SW1 is on. On the other hand, if the transmission command cannot be received even if a certain period of time has elapsed (N in step S14 and Y in step S17), the seat unit 12 immediately returns to step S12.

[0031] In contrast, if the on-off information of the seat switch SW1 detected in step S12 is information indicating the off state of the seat switch SW1 (N in step S13), the seat unit 2 causes the timer 222 to start counting (step S13). At this time, since the power switch SW3 is kept on even when the seat switch SW1 is off, the power supply to the control section 22 is maintained.

[0032] Next, the seat unit 2 determines whether a transmission command has been received (step S19). The seat unit 2 waits until a transmission command is received (Y in step S19) and proceeds to step S20. In step S20, the seat unit 2 acquires the on / off information of the buckle switch SW2. Next, the seat unit 2 transmits the on / off information of the seat switch SW1 and the buckle switch SW2 acquired in steps S12 and S20 to the vehicle unit 3 (step S21) and ends the processing. The on / off information of the seat switch SW1 transmitted in step S21 is information indicating an off of the seat switch SW1.

[0033] Upon completion of taking a predetermined time period, the timer 222 outputs an off signal to the power switch SW3. Accordingly, the power switch SW3 is turned off, and the power supply from the battery 21 to the control section 22 is cut off. The predetermined time period is set to be a time period longer than the specified time period, which is a transmission interval of the transmission command transmitted by the in-vehicle unit 3, as described above. Therefore, during a period in which the timer 222 takes the predetermined time period, the seat unit 2 can receive the transmission command (Y in step S19) and transmits a fact that the seat switch SW1 is turned off to the in-vehicle unit 3 (step S21).It should be noted that in cases such as one where the vehicle is stopped with the IG on, the transmission command cannot be transmitted from the vehicle unit 3 after a predetermined period of time has elapsed since the start of the count of the timer 222. In this case, while the seat unit 2 waits for reception of the transmission command (step S19), the timer 222 stops counting (timing) and the power supply is cut off, and thus the on-off information is not transmitted.

[0034] According to the above-described embodiments, information about the electronic devices (the seat switch SW1 and the buckle switch SW2) is not transmitted from the seat unit 2 during a period in which the vehicle unit 3 determines that communication with the seat unit 2 is not necessary. Therefore, the service life (running time) of the battery 21 can be extended.

[0035] According to the above-described embodiment, the seat switch SW1 is connected in parallel with the power switch SW3, and the control section 22 turns on the power switch SW3 in response to the seat switch SW1 being turned on, and turns off the power switch SW3 after a predetermined period of time has elapsed since the seat switch SW1 was turned off. Accordingly, when the occupant sits on the sliding seat 4, the seat switch SW1 is turned on to supply power from the battery 21 to the control section 22, thereby enabling communication with the vehicle unit 3. When the occupant leaves the sliding seat 4, the seat switch SW1 is turned off, but the power switch SW3 remains on, and the power supply to the control section 22 is maintained until a predetermined period of time has elapsed.Therefore, the seat unit can transmit the fact that the seat switch SW1 is off to the vehicle unit 3 during the elapse of the predetermined time period. Since the control section 22 turns off the power switch SW3 after the time period has elapsed since the seat switch SW1 was turned off, power is saved by cutting off the power supply to the control section 22 during a period in which the occupant is not sitting on the sliding seat 4.

[0036] While the present invention has been described with reference to certain exemplary embodiments thereof, the scope of the present invention is not limited to the exemplary embodiments described above, and it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the scope of the present invention as determined by the appended claims.

[0037] According to the above-described embodiment, when the IG switch is on and the vehicle speed is 3 km / h or higher, the in-vehicle unit 3 transmits a transmission command to the seat unit 2, and the invention is not limited to this. The in-vehicle unit 3 may transmit a transmission command to the seat unit 2 during a period in which the IG switch is on. Furthermore, the in-vehicle unit 3 may transmit a transmission command to the seat unit 2 when the vehicle speed is 3 km / h or higher.

[0038] Furthermore, according to the above-described embodiment, the power supply from the battery 21 to the control section 22 is coupled with the on and off of the seat switch SW1 in the seat unit 2, and the invention is not limited thereto. If the operating time of the battery 21 can be sufficiently extended simply by transmitting the transmission command during a period in which the vehicle unit 3 determines that communication with the seat unit 2 is necessary, it is not necessary to couple the power supply from the battery 21 to the control section 22 with the on and off of the switch SW1.

[0039] Furthermore, according to the above-described embodiment, the seat unit 2 is attached to the sliding seat 4, but the invention is not limited thereto. The seat unit 2 may be attached to a seat, and may be attached to a seat with a rotation device.

[0040] Furthermore, according to the above-described embodiment, the timer 222 is provided separately from the wireless communication IC 221A, and the invention is not limited thereto. A timer integrated into the wireless communication IC 221A can be used as the timer 222.

[0041] Next, a reference example of the communication system 1 with reference to Fig. 6 described. In Fig. 6 are the same components as those described above Fig. 2 in the first embodiment, denoted by the same reference numerals, and a detailed description thereof will be omitted. In the reference example, the seat switch SW1 and the power switch SW3 are not provided between the control section 22 and the battery 21, and power is continuously supplied to the control section 22. In the present reference example, the wireless communication IC 221A can switch between two states: a wake-up state in which power consumption is large and processing speed is high, and a sleep state in which power consumption is low and processing speed is lower. The wireless communication IC 221A switches to the wake-up state in response to receiving a wake-up signal from the in-vehicle unit 3 and switches to the sleep state in response to receiving a sleep signal.The wireless communication IC 221A can detect an on-off state of the switch SW1 and the buckle switch SW2.

[0042] Next, operations of the communication system 1 will be briefly described. When an IG switch is on and a vehicle speed is equal to or above 3 km / h, the vehicle unit 3 transmits a wake-up signal to the seat unit 2. When the IG switch is on and the vehicle speed is less than 3 km / h, the vehicle unit transmits a sleep signal to the seat unit 2.

[0043] The vehicle unit 3 retransmits the wake-up signal and the sleep signal until a reception signal is received from the seat unit 2, determines that the seat unit 2 is irregular if the reception signal cannot be received even if the number of retransmission times exceeds 100, and transmits a determination result to the BCM 6.

[0044] On the other hand, the seat unit 2 enters the sleep state when the sleep signal is received, and enters the wake-up state when the wake-up signal is received, and performs a switching state transmission. Regarding the switching state transmission, a state of the seat switch SW1 and the buckle switch SW2 is regularly read out and transmitted if there is a change in the switching state. The seat unit 2 transmits the switching state every regular transmission timer = 1 s if the seat switch SW1 is on, even if there is no change in the switching state, and transmits the switching state every regular transmission timer = 10 s if the seat switch SW1 is off. Further, the seat unit 2 repeats the switching state transmission until a reception signal is received from the vehicle unit 3 in response to the switch state transmission.If the reception signal cannot be received even if the number of times of transmission of the switch state exceeds 100, the seat unit 2 determines that the vehicle unit is irregular and enters the sleep state.

[0045] Next, detailed operations of the communication system 1, which are schematically described above, will be explained with reference to the Fig. 7A to 8B. First, as described in the Fig. 7A and Fig. As shown in Figure 7B, the wireless communication IC 311 of the in-vehicle unit 3 determines whether a regular routine (10 ms) has elapsed (step S101). The in-vehicle unit 3 waits for the regular routine to complete (Y in step S101) and determines whether the IG switch is on and a vehicle speed is 3 km / h or above (steps S102 and S103).

[0046] If the IG switch is on and the vehicle speed is 3 km / h or higher (Y in step S102 and Y in step S103), the in-vehicle unit 3 proceeds to step S104. In step S104, the in-vehicle unit 3 determines whether a wake-up signal has been transmitted and whether a reception signal from the seat unit 2 has subsequently been received. If the wake-up signal has not yet been transmitted (N in step S104), the in-vehicle unit 3 transmits the wake-up signal (step S105). Further, if the wake-up signal has been transmitted but the reception signal from the seat unit 2 has not yet been received (N in step S104), the in-vehicle unit 3 transmits the wake-up signal again (step S105).

[0047] Thereafter, the in-vehicle unit 3 performs a reception confirmation until a reception wait time elapses (steps S106 and S108). If the reception signal is received (Y in step S106), the in-vehicle unit 3 resets a retransmission counter of the wake-up signal (step S107) and then returns to step S101. The in-vehicle unit 3, having returned to step S101, determines in step S104 that, after transmitting the wake-up signal, the reception signal can be received by the seat unit 2 (Y in step S104) and immediately returns to step S101 without transmitting a signal.

[0048] On the other hand, if the reception signal cannot be received even if the reception waiting time has elapsed (Y in step S108), the vehicle unit 3 adds 1 to the retransmission count (step S109). Accordingly, the number of times the wake-up signal has been retransmitted is counted by the retransmission counter.

[0049] Next, the vehicle unit 3 determines whether the retransmission counter has exceeded 100 (step S110). If the retransmission counter has not exceeded 100 (N in step S110), the vehicle unit 3 immediately returns to step S101. On the other hand, if the retransmission counter has exceeded 100 (Y in step S110), the vehicle unit 3 transmits an abnormality (error) of the seat unit 2 to the BCM 6 (step S111) and then returns to step S101.

[0050] In contrast, if the IG switch is not on and the vehicle speed is less than 3 km / h (N in step S102 and N in step S103), the vehicle unit 3 proceeds to step S112. In step S112, the vehicle unit 3 determines whether a sleep signal has been transmitted and whether a reception signal from the seat unit 2 has been received thereafter. If the sleep signal has not yet been transmitted (N in step S112), the vehicle unit 3 transmits the sleep signal (step S113). Further, if the sleep signal has been transmitted but the reception signal from the seat unit 2 has not yet been received (N in step S112), the vehicle unit 3 transmits the sleep signal again (step S113).

[0051] Thereafter, the in-vehicle unit 3 performs a reception confirmation until a reception wait time elapses (steps S114 and S116). If the reception signal can be received (Y in step S114), the in-vehicle unit 3 resets a sleep signal retransmission counter (step S115) and then returns to step S101. The in-vehicle unit 3, having returned to step S101, determines in step S112 that, after transmitting a sleep signal, the reception signal can be received from the seat unit 2 (Y in step S112) and immediately returns to step S101 without transmitting a signal.

[0052] On the other hand, if the reception signal cannot be received even if the reception wait time has elapsed (Y in step S116), the vehicle unit 3 adds 1 to the retransmission counter (step S117). Accordingly, the number of times the sleep signal has been retransmitted is counted by the retransmission counter.

[0053] The vehicle unit 3 then determines whether the retransmission counter has exceeded 100 (step S113). If the retransmission counter has not exceeded 100 (N in step S118), the vehicle unit 3 immediately returns to step S101. On the other hand, if the retransmission counter has exceeded 100 (Y in step S118), the vehicle unit 3 transmits an abnormality (error) of the seat unit 2 to the BCM 6 (step S119) and then returns to step S101.

[0054] In addition to the Fig. 7A and Fig. 7B, the vehicle unit 3 executes reception processing for receiving information about the switching state from the seat unit 2, and when the information about the switching state is received, transmits the information to the BCM 6 and transmits a reception signal to the seat unit 2.

[0055] As in the Fig. 8A and Fig. As shown in Figure 8B, upon receiving a wake-up signal (Y in step S201), the seat unit 2 transmits a reception signal to the vehicle unit 3 and then enters the wake-up state (step S202). After that, the seat unit 2 waits for the regular routine (100 ms) to complete (Y in step S203) and determines whether a sleep signal has been received from the vehicle unit 3 (step S204).

[0056] If the sleep signal is not received (N in step S204), the seat unit 2 determines whether a transmission counter, to be described below, has exceeded 100 (step S205). If the transmission counter has not exceeded 100 (N in step S205), the seat unit 2 reads the state of the seat switch SW1 and the buckle switch SW2 (step S206). As a result of the reading, if there is a change in the switching state (Y in step S207), the seat unit 2 transmits the switching state (step S208) and resets a regular transmission timer (step S209).

[0057] The seat unit 2 sets the regular transmission timer to 1 second (step S211) if the seat switch SW1 is on (Y in step S210), and sets the regular transmission timer to 10 seconds (step S212) if the seat switch SW1 is off (N in step S210), and then proceeds to the next step. Next, the seat unit 2 confirms receipt of the reception signal from the in-vehicle unit 3 related to the switch state transmission until the reception wait time elapses (steps S213 and S214). Upon receipt of the reception signal (Y in step S213), the seat unit 2 resets the transmission counter (step S22) and returns to step S201.

[0058] On the other hand, if the reception signal cannot be received even if the reception waiting time has elapsed (Yes in step S214), the seat unit 2 adds 1 to the transmission counter (step S62) and returns to step S201. Accordingly, the number of times the switch state has been transmitted is counted by the transmission counter.

[0059] If there is no change in the switching state (N in step S207), the seat unit determines whether the regular transmission timer has overflowed (step S217). If there is no overflow (N in step S217), the seat unit 2 immediately returns to step S201. On the other hand, if there is an overflow (Y in step S217), the seat unit 2 transmits the switching state (step S218) and resets the regular transmission timer (step S219), and proceeds to step S213.

[0060] When the seat unit 2 receives the sleep signal (Y in step S204) and the transmission counter exceeds 100 (Y in step S205), the seat unit 2 transmits a reception signal to the vehicle unit 3, and then enters the sleep state (step S220) and returns to step S201.

[0061] According to one aspect of the exemplary embodiments described above, a communication system (1) comprises a seat unit (2) configured to be mounted on a seat (4) of a vehicle and to receive a power supply from a battery (21) for operation, and a vehicle unit (3) configured to wirelessly communicate with the seat unit (2). The vehicle unit (3) comprises a determination section (311) configured to determine whether communication with the seat unit (2) is necessary, and a command transmission section (311) configured to transmit to the seat unit (2) a transmission command requesting the seat unit (2) to transmit information via an electronic device (SW1, SW2) mounted on the seat (4) during a period in which the determination section (311) determines that communication with the seat unit (2) is necessary.The seat unit (2) is designed to transmit the information via the electronic device (SW1, SW2) upon receipt of the transmission command.

[0062] The seat unit (2) may comprise a seat switch (SW1) configured to turn on when sitting on the seat (4) is detected and to turn off when leaving the seat (4) is detected, a control section (22) configured to control wireless communication with the vehicle stop (3), and a power switch (SW3) configured to turn on and off a power supply from the battery (21) to the control section (22). The switch (SW1) is connected in parallel to the power switch (SW3). The control section (22) is configured to turn on the power switch (SW3) in response to turning on the seat switch (SW1) and to turn off the power switch (SW3) after a predetermined period of time has elapsed since the switch (SW1) was turned off.

[0063] The determination section (311) may be configured to determine whether communication with the seat unit (2) is necessary based on at least one of an on-off state of an ignition switch of the vehicle and a speed of the vehicle.

[0064] According to another aspect of the exemplary embodiments described above, a vehicle unit (3) is configured to wirelessly communicate with a seat unit (2) mounted on a seat (4) of a vehicle, wherein the seat unit is configured to receive a power supply from a battery (21) for operation. The vehicle unit (3) comprises a determination section (311) configured to determine whether communication with the seat unit (2) is necessary, and a command transmission section (311) configured to transmit to the seat unit (2) a transmission command requesting the seat unit (2) to transmit information via an electronic device (SW1, SW2) mounted on the seat (4) during a period in which the determination section (311) determines that communication with the seat unit (2) is necessary.

[0065] According to another aspect of the exemplary embodiments described above, a seat unit (2) is configured to be attached to a seat (4) of a vehicle and to receive a power supply from a battery (21) for operation, wherein the seat unit (2) is configured to wirelessly communicate with the above-described vehicle unit (3). The seat unit (2) comprises an information transmission section (221A) configured to transmit information via an electronic device (SW1, SW2) upon receipt of the transmission command from the vehicle unit (3).

Claims

[1] A communication system (1) comprising a seat unit (2) adapted to be mounted on a seat (4) of a vehicle and to receive a power supply from a battery (21) for operation, and a vehicle unit (3) adapted to wirelessly communicate with the seat unit (2), wherein the vehicle unit (3) comprises a determination section (311) configured to determine whether communication with the seat unit (2) is necessary, and a command transmission section (311) configured to transmit to the seat unit (2) a transmission command requesting the seat unit (2) to transmit information via an electronic device (SW1, SW2) mounted on the seat (4) during a period in which the determination section (311) determines that communication with the seat unit (2) is necessary, and wherein the seat unit (2) is configured to transmit the information via the electronic device (SW1, SW2) upon receipt of the transmission command. [2] Communication system (1) according to claim 1, wherein the seat unit (2) comprises a seat switch (SW1) configured to be turned on when sitting on the seat (4) is detected and to be turned off when leaving the seat (4) is detected, a control section (22) configured to control wireless communication with the vehicle unit (3), and a power switch (SW3) configured to turn on and off the power supply from the battery (21) to the control section (22), wherein the seat switch (SW1) is connected in parallel with the power switch (SW3), and wherein the control section (22) is configured to turn on the power switch (SW3) in response to turning on the seat switch (SW1), and to turn off the power switch (SW3) after a predetermined period of time has elapsed from turning off the seat switch (SW1). [3] The communication system (1) according to claim 1 or 2, wherein the determining section (311) is configured to determine whether communication with the seat unit (2) is necessary based on at least one of an on-off state of an ignition switch of the vehicle and a speed of the vehicle. [4] A vehicle unit (3) adapted to wirelessly communicate with a seat unit (2) mounted on a seat (4) of a vehicle, the seat unit (2) being adapted to receive a power supply from a battery (21) for operation, the vehicle unit (3) comprising: a determination section (311) configured to determine whether communication with the seat unit (2) is necessary; and a command transmission section (311) configured to transmit to the seat unit (2) a transmission command requesting the seat unit (2) to transmit information via an electronic device (SW1, SW2) mounted on the seat (4) during a period in which the determination section (311) determines that communication with the seat unit (2) is necessary. [5] A seat unit (2) adapted to be mounted on a seat (4) of a vehicle and to receive a power supply from a battery (21) for operation, wherein the seat unit (2) is adapted to wirelessly communicate with a vehicle unit (3) according to claim 4, wherein the seat unit (2) comprises an information transmission section (221A) configured to transmit information via an electronic device (SW1, SW2) upon receipt of a transmission command from the vehicle unit (3).

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