Wireless sensor terminal, wireless sensor system, and data transmission method

Abstract

To provide a wireless sensor terminal capable of efficiently transmitting data collected by a sensor.SOLUTION: A wireless sensor terminal 100 comprises a sensor information acquisition unit 111, a sensor information determination unit 112, a transmission interval change unit 113, and a transmission unit 114. The sensor information acquisition unit 111 acquires sensor information from a sensor. On the basis of the sensor information, the sensor information determination unit 112 determines whether or not a predetermined state is detected by the sensor. On the basis of an ON-OFF state of a transmission flag showing whether or not to be timing for transmitting the sensor information to an ECU and a result determined by the sensor information determination unit 112, the transmission interval change unit 113 changes the ON-OFF state of the transmission flag. At timing at which the sensor information is acquired by the sensor information acquisition unit and in the case that the transmission flag is ON, the transmission unit 114 transmits the sensor information.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a wireless sensor terminal, a wireless sensor system, and a data transmission method. [Background technology]

[0002] In recent years, wireless communication systems have been proposed in which vehicles are equipped with wireless communication devices for outside the vehicle, and communication is performed between the vehicle and an external base station or between vehicles themselves. Patent Document 1 discloses a communication control device used in a vehicle-to-vehicle communication system. In the communication control device disclosed in Patent Document 1, specific road connection points such as intersections and junctions on expressways are provided, and when a vehicle approaches a road connection point, the communication cycle is changed to control the amount of communication. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-175209 A Summary of the Invention [Problem to be solved by the invention]

[0004] In wireless communication, as the number of sensors and the amount of information increase, the amount of communication (amount of data) transmitted and received increases, causing interference and collisions in the transmitted and received data. The communication control device disclosed in Patent Document 1 controls the amount of communication by changing the communication cycle for inside and outside the range of a road connection point. However, the control for inside and outside the range of a road connection point is not control of the actual traffic volume, and there are cases where the traffic volume is low within the range of a road connection point and high outside the range of a road connection point. In other words, the communication control device disclosed in Patent Document 1 does not control communication reflecting the conditions around the vehicle, such as the actual traffic volume.

[0005] The present invention has been made in consideration of the problems inherent in the conventional techniques, and an object of the present invention is to provide a wireless sensor terminal capable of efficiently transmitting data collected by a sensor. [Means for solving the problem]

[0006] A wireless sensor terminal according to an embodiment of the present invention is a wireless sensor terminal that transmits sensor information collected by a sensor to an ECU, and includes a sensor information acquisition unit that acquires the sensor information from the sensor, a sensor information determination unit that determines whether or not a predetermined state has been detected in the sensor based on the sensor information, a transmission interval change unit that changes the on / off state of a transmission flag indicating whether or not it is the timing to transmit the sensor information to the ECU and the result determined by the sensor information determination unit, and a transmission unit that transmits the sensor information to the ECU when the transmission flag is on at the timing when the sensor information acquisition unit acquires the sensor information.

[0007] A wireless sensor system according to yet another aspect of the present invention is a wireless sensor system comprising a plurality of wireless sensor terminals that transmit sensor information collected by the sensors to an ECU, and an ECU, wherein the wireless sensor terminals comprise a sensor information acquisition unit that acquires sensor information from the sensors, a sensor information determination unit that determines whether or not a predetermined state has been detected in the sensor based on the sensor information, a transmission interval change unit that changes the on / off state of a transmission flag indicating whether or not it is the timing to transmit the sensor information to the ECU and the result determined by the sensor information determination unit, and a transmission unit that transmits the sensor information to the ECU when the transmission flag is on at the timing when the sensor information acquisition unit acquires the sensor information.

[0008] A data transmission method according to another aspect of the present invention is a data transmission method executed by a computer, which acquires sensor information from a sensor, determines whether or not a specified state has been detected in the sensor based on the sensor information, changes the on / off state of a transmission flag indicating whether it is time to transmit the sensor information to an ECU and based on the determination result of whether or not the specified state has been detected in the sensor, and transmits the sensor information when the sensor information has been acquired and the transmission flag is on. Effect of the Invention

[0009] According to the present invention, it is possible to provide a wireless sensor terminal capable of efficiently transmitting data collected by a sensor. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing a basic configuration of a wireless sensor system according to an embodiment of the present invention. [Diagram 2] 1 is a diagram for explaining an example of traveling of a vehicle equipped with a wireless sensor terminal according to the embodiment; [Figure 3A] 5 is a timing chart for explaining timing of transmitting sensor information from each sensor of the wireless sensor system according to the present embodiment to an ECU. [Figure 3B] 10 is a timing chart showing another example of the transmission timing of the sensor information transmitted from each sensor of the wireless sensor system according to the present embodiment to the ECU. [Figure 4] 1 is a block diagram showing a schematic configuration of a wireless sensor terminal according to an embodiment of the present invention; [Diagram 5] 6 is a flowchart showing an example of the operation of the wireless sensor terminal according to the embodiment. [Figure 6A] 11 is a diagram for explaining a process for changing a transmission interval according to the embodiment; FIG. [Figure 6B] 11 is a diagram for explaining a process for changing a transmission interval according to the embodiment; FIG. [Figure 6C]11 is a diagram for explaining a process for changing a transmission interval according to the embodiment; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The wireless sensor system 1 according to this embodiment will be described in detail below with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios. In addition, in the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0012] (Schematic configuration of wireless sensor system 1) A wireless sensor system 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 shows an example of the wireless sensor system 1 according to this embodiment in which a wireless sensor terminal 100 is attached to a vehicle 10. As shown in Fig. 1, the wireless sensor system 1 has an ECU 20 (Electronic Control Unit) provided at the front of the vehicle 10 in the traveling direction, and each sensor provided on the vehicle 10 communicates with this ECU 20.

[0013] In this embodiment, the vehicle 10 is provided with a front sensor 100a, a back sensor 100b, a side sensor 100c, and a side sensor 100d, which are sensor terminals for grasping the environment around the vehicle 10, at each end of the front, rear, left and right of the vehicle 10. The front sensor 100a, the back sensor 100b, the side sensor 100c, and the side sensor 100d periodically transmit information from an object detection sensor as sensor information to the ECU 20. The object detection sensor is a sensor that detects (senses) whether or not an object such as a vehicle or a person exists in the front, back, and side directions, respectively. In addition, the front sensor 100a, the back sensor 100b, the side sensor 100c, and the side sensor 100d transmit sensor information to the ECU 20 at a periodic time of 100 ms.

[0014] In this embodiment, the front sensor 100a, the back sensor 100b, the side sensor 100c, and the side sensor 100d correspond to the wireless sensor terminal 100. That is, in this embodiment, the front sensor 100a, the back sensor 100b, the side sensor 100c, and the side sensor 100d have the functions of the wireless sensor terminal 100 described below.

[0015] A battery sensor 200 is provided at the rear of the vehicle 10, and the battery sensor 200 periodically transmits sensor information such as the battery state to the ECU 20. For example, the battery sensor 200 transmits the sensor information such as the battery state to the ECU 20 at a periodic time of 80 ms.

[0016] Furthermore, each seat of the vehicle 10 is provided with a seat sensor 300a-300d, which periodically transmits sensor information such as the riding status to the ECU 20 when a person is seated in the seat. Hereinafter, when there is no need to distinguish between the seat sensors 300a-300d, they will be simply referred to as "seat sensor 300." For example, the seat sensor 300 transmits sensor information such as the riding status (seating status) to the ECU 20 at a periodic time of 1 second.

[0017] Fig. 2 shows a state in which a vehicle 10 equipped with the wireless sensor system 1 according to this embodiment is traveling on a road. In the example shown in Fig. 2, a front sensor 100a and a back sensor 100b of the vehicle 10 detect objects (vehicles, etc.) traveling in front of and behind the vehicle 10. In the example shown in Fig. 2, a side sensor 100c and a side sensor 100d of the vehicle 10 do not detect any objects (vehicles, etc.).

[0018] 3A and 3B are examples showing the timing of data transmission from each sensor provided in the vehicle 10 to the ECU 20. As shown in FIG. 3A and FIG. 3B, each sensor transmits sensor information to the ECU 20 at its respective periodic time. In addition, the seat sensor 300 starts communication with the ECU 20 when a person sits in the seat. For example, the example shown in FIG. 3A shows an example in which at time T10, a person sits in the passenger seat of the vehicle 10 shown in FIG. 1, and transmission of sensor information from the seat sensor 300b to the ECU 20 starts.

[0019] In the example shown in FIG. 3A, the wireless sensor system 1 according to this embodiment is not applied, and the side sensor 100c detects an object on the side of the vehicle 10. In the example shown in FIG.

[0020] In the example shown in FIG. 3A, at time T10, sensor information collected by the sensor is transmitted from the side sensor 100c to the ECU 20. Also, at time T10, the seat sensor 300b transmits sensor information to the ECU 20. That is, at time T10, the transmission of sensor information from the side sensor 100c and the seat sensor 300b collide. In this way, when the transmission of sensor information from each sensor collide, both of the colliding transmissions fail. Note that the sensor information that could not be communicated, such as the sensor information from the side sensor 100c and the seat sensor 300b at time T10, is transmitted together with the sensed data at the next timing.

[0021] 3B shows an example in which a vehicle or the like is not detected on the side of the side sensor 100c of the wireless sensor system 1 according to this embodiment, and the transmission interval of the sensor information from the side sensor 100c is changed. In this way, the transmission interval of the sensor information from the sensor is changed, thereby avoiding a collision with the transmission of the sensor information from the seat sensor 300b. The details of changing the transmission interval of the sensor information from each sensor will be described later.

[0022] (Configuration and Functions of Wireless Sensor Node 100) Next, the configuration and functions of the wireless sensor node 100 will be described with reference to the block diagram shown in FIG.

[0023] 4, the wireless sensor terminal 100 includes a control unit 110 and a storage unit 120. The control unit 110 includes a sensor information acquisition unit 111, a sensor information determination unit 112, a transmission interval change unit 113, and a transmission unit 114 as functions.

[0024] The wireless sensor terminal 100 may be configured as, for example, a computer. In this case, a computer program for causing the computer to function as the wireless sensor terminal 100 may be installed in the computer. By executing the computer program, the computer functions as a plurality of information processing circuits included in the wireless sensor terminal 100. In this embodiment, an example is shown in which the plurality of information processing circuits included in the wireless sensor terminal 100 are realized by software. However, it is of course possible to configure the information processing circuits by preparing dedicated hardware for executing each information process described below. Also, the plurality of information processing circuits may be configured by individual hardware. The sensor information acquisition unit 111, the sensor information determination unit 112, the transmission interval change unit 113, and the transmission unit 114 will be described in detail later.

[0025] The storage unit 120 stores the sensor information acquired by the sensor information acquisition unit 111 and information on a transmission flag, which will be described later, as data. The number of storage units 120 that store these pieces of data may be one or more. For example, a single storage unit 120 may be configured to store the data in separate areas. Alternatively, the data may be distributed and stored in a plurality of storage devices that are installed in physically separate locations.

[0026] Next, each function implemented in the control unit 110 will be described. The control unit 110 has a sensor information acquisition unit 111, a sensor information determination unit 112, a transmission interval change unit 113, and a transmission unit 114 as its functions. The control unit 110 also controls the wireless sensor terminal 100 as a whole, for example by running an operation system. Furthermore, the control unit 110 operates based on a program stored in the storage unit 120, and executes each function of the sensor information acquisition unit 111, the sensor information determination unit 112, the transmission interval change unit 113, and the transmission unit 114. Note that the program is not limited to being stored in the storage unit 120, and may be stored in, for example, a ROM (Read Only Memory) (not shown) in the wireless sensor terminal 100.

[0027] The sensor information acquisition unit 111 acquires sensor information from the sensors and stores it in the storage unit 120. The sensor information is, for example, information for grasping the environment around the vehicle 10, and specifically, information sensed by each sensor in the facing direction.

[0028] The sensor information determination unit 112 determines whether or not a predetermined state has been detected in the sensor based on the sensor information acquired by the sensor information acquisition unit 111. In this embodiment, the predetermined state is the state of the environment around the vehicle 10 when the sensor is the front sensor 100a, the back sensor 100b, the side sensor 100c, or the side sensor 100d. More specifically, the predetermined state is, for example, information indicating whether or not an object such as a vehicle exists in the direction (opposing direction) in which each sensor senses.

[0029] The transmission interval change unit 113 changes the on / off state of a transmission flag indicating whether it is time to transmit the sensor information to the ECU 20. In this embodiment, the transmission flag is, for example, information stored in the storage unit 120, and indicates whether it is time to transmit the sensor information to the ECU 20 by an on or off state. The on state of the transmission flag indicates that the sensor information is to be transmitted from the wireless sensor terminal 100 to the ECU 20. On the other hand, the off state of the transmission flag indicates that the sensor information is not to be transmitted from the wireless sensor terminal 100 to the ECU 20. In this embodiment, the transmission flag is on in an initial state such as when the wireless sensor terminal 100 is started. Note that the form of the transmission flag is not limited to this embodiment. For example, the transmission flag may be one-bit information indicating on / off temporarily stored in a volatile memory or a register of the storage unit 120.

[0030] In this embodiment, the transmission interval changing unit 113 changes the on / off state of the transmission flag based on the on / off state of the transmission flag and the result of the determination by the sensor information determining unit 112 .

[0031] Specifically, when the transmission interval change unit 113 determines that the sensor information determination unit 112 has detected a specified state, or when the sensor information determination unit 112 determines that the sensor information determination unit 112 has not detected a specified state and the transmission flag is off, the transmission interval change unit 113 turns on the transmission flag.

[0032] Furthermore, in this embodiment, when the sensor information determination unit 112 determines that a predetermined state has not been detected and the transmission flag is off, the transmission interval change unit 113 turns off the transmission flag.

[0033] The transmitter 114 transmits the sensor information to the ECU 20 when the transmission flag is on at the timing when the sensor information acquirer 111 acquires the sensor information.

[0034] (Outline of processing flow of the wireless sensor node 100) Next, the flow of processing in the wireless sensor terminal 100 will be shown using the flowchart shown in Fig. 5. In the flowchart shown in Fig. 5, the processing also ends when the power is turned off or an interrupt is issued to end the processing. In addition, in the following explanation of the flowchart, the same contents as those described above in the explanation of the wireless sensor terminal 100 will be omitted or simplified.

[0035] In step S501, the sensor information acquisition unit 111 judges whether it is the timing (detection timing) to acquire sensor information from the sensor. In step S501, if the sensor information acquisition unit 111 judges that it is the timing (detection timing) to acquire sensor information from the sensor (step S501: YES), the process proceeds to step S502. On the other hand, in step S501, if the sensor information acquisition unit 111 judges that it is not the timing (detection timing) to acquire sensor information from the sensor (step S501: NO), the process shown in FIG. 5 is terminated. In addition, the judgment process of step S501 is executed again after a predetermined time has elapsed. The detection timing is information set for each wireless sensor terminal 100, and the sensor information acquisition unit 111 judges the detection timing based on time information obtained from a timer (not shown) in the wireless sensor terminal 100, for example.

[0036] In step S502 , the sensor information acquisition unit 111 acquires sensor information from the sensor, and stores it in the storage unit 120 .

[0037] In step S503, the transmitter 114 determines whether the transmission flag is on or not. Here, the transmission flag is, for example, information stored in the storage unit 120 as described above, and is indicated by an on or off state. The transmission flag is on in an initial state, such as when the wireless sensor terminal 100 is started up. The on state of the transmission flag indicates that the wireless sensor terminal 100 transmits sensor information to the ECU 20. On the other hand, the off state of the transmission flag indicates that the wireless sensor terminal 100 does not transmit sensor information to the ECU 20.

[0038] In step S503, if the transmitting unit 114 determines that the transmission flag is on (step S503: YES), the process proceeds to step S504. On the other hand, in step S503, if the transmitting unit 114 determines that the transmission flag is off (step S503: NO), the process proceeds to step S505.

[0039] In step S504 , the transmission unit 114 transmits the sensor information stored in the storage unit 120 to the ECU 20 .

[0040] In step S505, the sensor information determination unit 112 determines whether or not a predetermined state has been detected in the sensor. In this embodiment, the predetermined state is a state indicating whether or not an object such as a vehicle has been detected in the sensing direction of the sensor. In step S505, if the sensor information determination unit 112 determines that an object has been detected (step S505: YES), the process proceeds to step S506. On the other hand, in step S505, if the sensor information determination unit 112 determines that an object has not been detected (step S505: NO), the process proceeds to step S507.

[0041] In step S506, the transmission interval change unit 113 turns on the transmission flag and ends the process. That is, the transmission flag turned on in step S506 is used in the next process flow when determining whether or not to transmit the sensor information to the ECU 20 (step S503).

[0042] In step S507, the transmission interval changing unit 113 determines whether the transmission flag is on. If the transmission interval changing unit 113 determines in step S507 that the transmission flag is on (step S507: YES), the process proceeds to step S508. On the other hand, if the transmission interval changing unit 113 determines in step S507 that the transmission flag is off (step S507: NO), the process proceeds to step S506.

[0043] In step S508, the transmission interval change unit 113 turns off the transmission flag and ends the process. That is, the transmission flag turned off in step S508 is used in the next process flow when determining whether or not to transmit the sensor information to the ECU 20 (step S503).

[0044] The processing of the transmission interval change unit 113 in steps S505 to S508 shown in the above flow will be explained using the timing charts shown in Figures 6A, 6B, and 6C. The processing of the transmission interval change unit 113 in steps S505 to S508 is performed based on the on / off state of the transmission flag and the determination result of whether or not a predetermined state has been detected by the sensor. Note that the timing charts shown in Figures 6A to 6C are simplified timing charts for explaining the relationship between the detection timing, transmission timing, and the transmission flag.

[0045] 6A to 6C, the detection timing indicated by a diagonal line pattern indicates that the sensor information determination unit 112 has detected an object. Also, timing not indicated by a diagonal line pattern indicates that the sensor information determination unit 112 has not detected an object. That is, the sensor information acquisition unit 111 acquires sensor information at regular intervals, and the sensor information determination unit 112 determines whether or not an object has been detected.

[0046] 6A to 6C, the timings indicated by the diagonal line patterns in the transmission timings indicate timings at which the transmission unit 114 transmits the sensor information to the ECU 20. The timings at which no diagonal line patterns are present in the transmission timings indicate that the transmission unit 114 does not transmit the sensor information to the ECU 20.

[0047] Fig. 6A shows an example of a case where the sensor information determination unit 112 changes from a state where an object is detected to a state where the object is not detected. Fig. 6B shows an example of a case where the sensor information determination unit 112 changes from a state where an object is not detected to a state where the object is detected. Fig. 6C shows an example of a case where the sensor information determination unit 112 changes from a state where an object is not detected to a state where the object is detected at a timing different from that in Fig. 6B.

[0048] Also, flows FL1, FL2, and FL3 shown in Figures 6A to 6C correspond to flows in the flowchart shown in Figure 5. That is, the flow in which the transmission flag is turned on in steps S505 and S506 in the flowchart of Figure 5 is referred to as flow FL1. Also, the flow in which the transmission flag is turned on in steps S507 and S506 in the flowchart of Figure 5 is referred to as flow FL2. Furthermore, the flow in which the transmission flag is turned off in steps S507 and S508 in the flowchart of Figure 5 is referred to as flow FL3.

[0049] At the detection timing of time T1 in Fig. 6A, the sensor information determination unit 112 detects an object, and the transmission flag is on. Therefore, at time T1, the transmission unit 114 transmits sensor information to the ECU 20. At time T1 in Fig. 6A, the sensor information determination unit 112 detects an object, so the above-mentioned processes of steps S505 and S506 (processing of flow FL1) are performed, and the transmission flag is on (no change).

[0050] At the detection timing of time T2 in Fig. 6A, the sensor information determination unit 112 does not detect an object, and the transmission flag is on. Therefore, at time T2, the transmission unit 114 transmits sensor information to the ECU 20. Also, at time T2 in Fig. 6A, the sensor information determination unit 112 does not detect an object, so the above-mentioned processes of step S507 and step S508 (processing of flow FL3) are performed, and the transmission flag is turned off.

[0051] At the detection timing of time T3 in Fig. 6A, the sensor information determination unit 112 does not detect an object, and the transmission flag is OFF. Therefore, at time T3, the transmission unit 114 does not transmit sensor information to the ECU 20. Also, at time T3 in Fig. 6A, the sensor information determination unit 112 does not detect an object, so the above-mentioned processes of step S507 and step S506 (processing of flow FL2) are performed, and the transmission flag is ON.

[0052] In Fig. 6A, the above-mentioned processes at times T2 and T3 are repeated after time T4. Thus, in the example shown in Fig. 6A, it is shown that the transmission interval (transmission period) of the sensor information from the wireless sensor terminal 100 is getting longer.

[0053] 6B and 6C show an example in which the transmission interval (transmission cycle) of the sensor information from the wireless sensor terminal 100 is shortened. Note that Fig. 6C shows an example in which the timing at which the sensor information determination unit 112 detects an object is different from that in Fig. 6B.

[0054] At the detection timing of time T1 in Fig. 6B, the sensor information determination unit 112 does not detect an object, and the transmission flag is OFF. Therefore, at time T1, the transmission unit 114 does not transmit sensor information to the ECU 20. Also, at time T1 in Fig. 6B, the sensor information determination unit 112 does not detect an object, so the above-mentioned processes of step S507 and step S506 (processing of flow FL2) are performed, and the transmission flag is ON.

[0055] At the detection timing of time T2 in Fig. 6B, the sensor information determination unit 112 does not detect an object, and the transmission flag is on. Therefore, at time T2, the transmission unit 114 transmits sensor information to the ECU 20. Also, at time T2 in Fig. 6B, the sensor information determination unit 112 does not detect an object, so the above-mentioned processes of step S507 and step S508 (processing of flow FL3) are performed, and the transmission flag is turned off.

[0056] At the detection timing of time T3 in Fig. 6B, the sensor information determination unit 112 detects an object, and the transmission flag is OFF. Therefore, at time T3, the transmission unit 114 does not transmit sensor information to the ECU 20. Also, at time T3 in Fig. 6B, the sensor information determination unit 112 detects an object, so the above-mentioned processes of steps S505 and S506 (processing of flow FL1) are performed, and the transmission flag is ON.

[0057] At the detection timing of time T4 in Fig. 6B, the sensor information determination unit 112 detects an object, and the transmission flag is on. Therefore, at time T4, the transmission unit 114 transmits sensor information to the ECU 20. Also, at time T4 in Fig. 6B, the sensor information determination unit 112 detects an object, so the above-mentioned processes of steps S505 and S506 (processing of flow FL1) are performed, and the transmission flag is on.

[0058] In Fig. 6B, the process at time T4 in Fig. 6B described above is repeated after time T5. Thus, in the example shown in Fig. 6B, it is shown that the transmission interval (transmission period) of the sensor information from the wireless sensor terminal 100 is shortened.

[0059] At the detection timing of time T1 in Fig. 6C, the sensor information determination unit 112 does not detect an object, and the transmission flag is OFF. Therefore, at time T1, the transmission unit 114 does not transmit sensor information to the ECU 20. Also, at time T1 in Fig. 6C, the sensor information determination unit 112 does not detect an object, so the above-mentioned processes of step S507 and step S506 (processing of flow FL2) are performed, and the transmission flag is ON.

[0060] At the detection timing of time T2 in Fig. 6C, the sensor information determination unit 112 does not detect an object, and the transmission flag is on. Therefore, at time T2, the transmission unit 114 transmits sensor information to the ECU 20. Also, at time T2 in Fig. 6C, the sensor information determination unit 112 does not detect an object, so the above-mentioned processes of step S507 and step S508 (processing of flow FL3) are performed, and the transmission flag is turned off.

[0061] At the detection timing of time T3 in Fig. 6C, the sensor information determination unit 112 does not detect an object, and the transmission flag is OFF. Therefore, at time T3, the transmission unit 114 does not transmit sensor information to the ECU 20. Also, at time T3 in Fig. 6C, the sensor information determination unit 112 does not detect an object, so the above-mentioned processes of step S507 and step S506 (processing of flow FL2) are performed, and the transmission flag is ON.

[0062] At the detection timing of time T4 in Fig. 6C, the sensor information determination unit 112 detects an object, and the transmission flag is on. Therefore, at time T4, the transmission unit 114 transmits sensor information to the ECU 20. Also, at time T4 in Fig. 6C, the sensor information determination unit 112 detects an object, so the above-mentioned processes of steps S505 and S506 (processing of flow FL1) are performed, and the transmission flag is on.

[0063] In Fig. 6C, the process at time T4 in Fig. 6C described above is repeated after time T5. Thus, in the example shown in Fig. 6C, it is shown that the transmission interval (transmission period) of the sensor information from the wireless sensor terminal 100 is shortened.

[0064] 6A to 6C, the transmission interval change unit 113 changes the transmission flag used to determine whether or not to transmit sensor information to the ECU 20 at the next detection timing, but the embodiment is not limited to this configuration. For example, the transmission unit 114 may be configured to determine whether to transmit the sensor information to the ECU 20 at the detection timing at which the transmission interval change unit 113 changes the transmission flag.

[0065] As described above, the wireless sensor terminal 100 in this embodiment includes a sensor information acquisition unit 111, a sensor information determination unit 112, a transmission interval change unit 113, and a transmission unit 114. The sensor information acquisition unit 111 acquires sensor information from the sensor. The sensor information determination unit 112 determines whether or not a predetermined state has been detected in the sensor based on the sensor information. The transmission interval change unit 113 changes the on / off state of a transmission flag indicating whether or not it is timing to transmit the sensor information to the ECU 20 based on the result of the determination by the sensor information determination unit 112. The transmission unit 114 transmits the sensor information when the transmission flag is on at the timing when the sensor information acquisition unit 111 acquires the sensor information.

[0066] This enables each wireless sensor terminal 100 to appropriately calculate the transmission interval according to the status of each sensor. This makes it possible to prevent collisions and interference of sensor information from each wireless sensor terminal 100. For example, when the wireless sensor terminal 100 does not detect any objects such as vehicles or people around the vehicle 10, it becomes possible to avoid collisions of transmissions from each sensor by lengthening the transmission interval of sensor information.

[0067] Furthermore, the sensor information determination unit 112 of the wireless sensor terminal 100 determines that a predetermined state has been detected when an object is sensed by the sensor. This makes it possible for each wireless sensor terminal 100 to appropriately calculate the transmission interval without requiring, for example, a process of changing the transmission interval by an external vehicle communication device.

[0068] Furthermore, the transmission interval changing unit 113 of the wireless sensor terminal 100 turns on the transmission flag when it is determined that the sensor information determining unit 112 has detected a predetermined state. Furthermore, the transmission interval changing unit 113 turns on the transmission flag when it is determined that the sensor information determining unit 112 has not detected a predetermined state and the transmission flag is off. Furthermore, the transmission interval changing unit 113 turns off the transmission flag when it is determined that the sensor information determining unit 112 has not detected a predetermined state and the transmission flag is off.

[0069] As a result, the transmission interval change unit 113 of the wireless sensor terminal 100 changes the timing of transmitting sensor information to the ECU 20 by turning the transmission flag on and off. This makes it possible to easily set the transmission interval (transmission cycle) without the need for complex control, and makes it possible to more accurately avoid collisions of transmissions from each sensor. Furthermore, since the transmission interval is set using the transmission flag, it is possible to easily adjust the sensor interval for each sensor, and it is possible to realize a wireless sensor terminal 100 that corresponds to the wireless sensor system 1.

[0070] (Other embodiments) Although the embodiments have been described in detail with reference to the drawings, the present embodiments are not limited to the contents described in the above embodiments. The components described above include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the configurations described above can be appropriately combined. Various omissions, substitutions, or modifications of the configurations can be made without departing from the spirit of the embodiments.

[0071] In the above embodiment, the wireless sensor terminal 100 extends the transmission interval by not transmitting one time in order to reduce unnecessary communication traffic depending on the environment around the vehicle 10, but the embodiment is not limited to this configuration. For example, a maximum value for extending the transmission interval may be calculated in advance for each sensor, and the transmission interval may be extended based on the maximum value. In addition, this transmission interval may be set (updated) by a user or the like. This makes it possible to set an appropriate transmission interval depending on the sensor, and realizes a wireless sensor terminal 100 that can transmit sensor information more efficiently.

[0072] In the above embodiment, the front sensor 100a, the back sensor 100b, the side sensor 100c, and the side sensor 100d are configured to have a function of changing the transmission interval of the wireless sensor terminal 100, but the embodiment is not limited to this configuration. For example, a configuration having a function of changing the transmission interval may be applied to the seat sensor 300. For example, a child seat may be provided with a function of changing the transmission interval of the sensor information, and when an infant is sitting in the seat, the transmission interval of the sensor information may be shortened to realize an abandoned child detection function that frequently issues a warning.

[0073] In the above embodiment, the transmission interval is lengthened to reduce unnecessary communication traffic depending on the environment around the vehicle 10, but a configuration may be adopted in which a sensor such as a biosensor or drowsiness detector is provided with a function to change the transmission interval. For example, when an abnormality occurs in the biosensor or drowsiness detector, it is possible to appropriately call attention by shortening the transmission interval from the normal communication cycle. In other words, by making the transmission interval variable, such as shortening or lengthening, depending on the device or application equipped with the wireless sensor terminal 100, it is possible to realize the function of the wireless sensor terminal 100 suited to the device.

[0074] Furthermore, the scope of this embodiment includes a computer program (data transmission program) that causes a computer to execute the processing (data transmission method) in the wireless sensor terminal 100 described above, and a computer-readable recording medium on which the program is recorded. Any type of computer-readable recording medium may be used. Furthermore, the computer program is not limited to one recorded on the recording medium, and may be one transmitted via a telecommunications line, a wireless or wired communication line, a network such as the Internet, or the like.

[0075] The features of the wireless sensor terminal 100, the wireless sensor system 1, and the data transmission method of this embodiment will be described below.

[0076] The wireless sensor terminal 100 according to the first aspect is a wireless sensor terminal 100 that transmits sensor information collected by a sensor to the ECU 20, and includes a sensor information acquisition unit 111 that acquires the sensor information from the sensor. The wireless sensor terminal 100 also includes a sensor information determination unit 112 that determines whether or not a predetermined state has been detected in the sensor based on the sensor information. The wireless sensor terminal 100 also includes a transmission interval change unit 113 that changes the on / off state of a transmission flag indicating whether or not it is timing to transmit the sensor information to the ECU 20, based on the on / off state of a transmission flag and the result of the determination by the sensor information determination unit 112. The wireless sensor terminal 100 also includes a transmission unit 114 that transmits the sensor information to the ECU 20 when the transmission flag is on at the timing when the sensor information acquisition unit 111 acquires the sensor information.

[0077] According to the above configuration, each wireless sensor terminal 100 can appropriately calculate the transmission interval according to the status of each sensor. This makes it possible to prevent collisions and interference of sensor information from each wireless sensor terminal 100.

[0078] The sensor information determining unit 112 of the wireless sensor terminal 100 according to the second embodiment may determine that a predetermined state has been detected when an object is sensed by the sensor.

[0079] According to the above configuration, the wireless sensor terminal 100 can avoid collisions of transmissions from each sensor by lengthening the transmission interval of sensor information when it does not detect any object such as a vehicle or a person around the vehicle 10. Furthermore, according to the above configuration, the wireless sensor terminal 100 can appropriately calculate the transmission interval without requiring any process such as changing the transmission interval by an external vehicle communication device.

[0080] The transmission interval change unit 113 of the wireless sensor terminal 100 according to the third aspect may turn on the transmission flag when it is determined that the sensor information determination unit 112 has detected a predetermined state. Also, the transmission interval change unit 113 may turn on the transmission flag when it is determined that the sensor information determination unit 112 has not detected a predetermined state and the transmission flag is off. Furthermore, the transmission interval change unit 113 turns off the transmission flag when it is determined that the sensor information determination unit 112 has not detected a predetermined state and the transmission flag is off.

[0081] According to the above configuration, the wireless sensor terminal 100 changes the on / off state of the transmission flag based on the information indicating whether or not a predetermined state has been detected in the sensor information determination unit 112 and the state of the transmission flag. This makes it possible to easily set the transmission interval (transmission cycle) without requiring complex control, and makes it possible to more accurately avoid collisions of transmissions from each sensor. Furthermore, since the transmission interval is set using the transmission flag, it is possible to easily adjust the sensor interval for each sensor, and it is possible to realize a wireless sensor terminal 100 that corresponds to the wireless sensor system 1.

[0082] The wireless sensor system 1 according to the fourth embodiment includes a plurality of wireless sensor terminals 100 that transmit sensor information collected by the sensors to the ECU 20, and the ECU 20. The wireless sensor terminals 100 included in the wireless sensor system 1 include a sensor information acquisition unit 111 that acquires sensor information from the sensors. The wireless sensor terminals 100 also include a sensor information determination unit 112 that determines whether a predetermined state has been detected in the sensors based on the sensor information. The wireless sensor terminals 100 also include a transmission interval change unit 113 that changes the on / off state of a transmission flag that indicates whether it is time to transmit the sensor information to the ECU 20, and based on the result of the determination by the sensor information determination unit 112. The wireless sensor terminals 100 also include a transmission unit 114 that transmits the sensor information to the ECU 20 when the transmission flag is on at the timing when the sensor information acquisition unit 111 acquires the sensor information.

[0083] According to the above configuration, each wireless sensor terminal 100 in the wireless sensor system 1 can appropriately calculate the transmission interval according to the status of each sensor. This makes it possible to prevent collisions and interference of sensor information from each wireless sensor terminal 100.

[0084] A data transmission method according to a fifth aspect is a data transmission method executed by a computer, which acquires sensor information from a sensor. The data transmission method also determines whether or not a predetermined state has been detected in the sensor based on the sensor information. The data transmission method also changes the on / off state of a transmission flag indicating whether or not it is time to transmit the sensor information to ECU 20, and based on a determination result of whether or not the predetermined state has been detected in the sensor. Furthermore, the data transmission method transmits the sensor information when it is time to acquire the sensor information and the transmission flag is on.

[0085] According to the above configuration, the data transmission method enables each wireless sensor terminal 100 to appropriately calculate the transmission interval according to the status of each sensor. This makes it possible to prevent collisions and interference of sensor information from each wireless sensor terminal 100. [Explanation of symbols]

[0086] 1. Wireless Sensor System 20 ECU 100 Wireless sensor terminal 100a Front Sensor 100b Back sensor 100c, 100d Side sensor 111 Sensor information acquisition unit 112 Sensor information determination unit 113 Transmission interval change unit 114 Transmitter 120 Storage section 200 Battery Sensor 300, 300a, 300b, 300c, 300d Sheet Sensor

Claims

1. A wireless sensor terminal that transmits sensor information collected by a sensor that detects the presence of an object to an ECU, a sensor information acquisition unit that acquires the sensor information from the sensor; a sensor information determination unit that determines whether or not the object has been detected by the sensor based on the sensor information; a transmission interval changing unit that changes the on / off state of a transmission flag indicating whether or not it is time to transmit the sensor information to the ECU, based on an on / off state of the transmission flag and a result of the determination by the sensor information determining unit; a transmitter that transmits the sensor information to the ECU when the transmission flag is on at the timing when the sensor information acquisition unit acquires the sensor information.

2. the transmission interval change unit turns on the transmission flag when the sensor information determination unit determines that the object has been detected, or when the sensor information determination unit determines that the object has not been detected and the transmission flag is off; 2. The wireless sensor terminal according to claim 1, wherein said transmission interval changing unit turns off said transmission flag when said sensor information determining unit determines that said object has not been detected and said transmission flag is on.

3. A wireless sensor system comprising: a plurality of wireless sensor terminals that transmit sensor information collected by a sensor that detects the presence of an object to an ECU; and the ECU, The wireless sensor terminal comprises: a sensor information acquisition unit that acquires the sensor information from the sensor; a sensor information determination unit that determines whether or not the object has been detected by the sensor based on the sensor information; a transmission interval changing unit that changes the on / off state of a transmission flag indicating whether or not it is time to transmit the sensor information to the ECU, based on an on / off state of the transmission flag and a result of the determination by the sensor information determining unit; a transmitter that transmits the sensor information to the ECU when the transmission flag is on at the timing when the sensor information acquisition unit acquires the sensor information.

4. 1. A computer-implemented method for transmitting data, comprising: Acquire sensor information from a sensor that detects the presence of an object; determining whether the object has been detected by the sensor based on the sensor information; changing the on / off state of a transmission flag indicating whether or not it is time to transmit the sensor information to an ECU, and based on a determination result of whether or not the object has been detected by the sensor; The data transmission method further comprises transmitting the sensor information when the sensor information is acquired and the transmission flag is on.

Images