JP2011068351A - Radio communication system for vehicle control - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make real time property and reliability compatible in a radio communication system for vehicle. <P>SOLUTION: The radio communication system includes a first transmission node (Node 1) 10, a second transmission node (Node 2) 20, a receiving node (Node N) 30 and a communication route 40. For instance, the first transmission node 10 evaluates a communication time and reliability of the communication route 40 by employing a self route evaluation means 12. The radio communication route 41 with "high" reliability which is a route satisfying the reliability set at the data reliability setting part 13 is selected from a plurality of radio communication routes 41-43 satisfying the communication restriction time set on the transmission data 11 by employing a data/route responding means 14. The first transmission node 10 transmits the transmission data 11 to the receiving node 30 by employing the radio communication route 41. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a system that transmits and receives data by communication in a vehicle control system, and more particularly to a vehicle control wireless communication system that performs vehicle control by wireless communication.

As a wireless communication system, conventionally, transmission quality of a transmission path is detected from a plurality of relay paths,
There is a method in which the transmission quality of a plurality of relay routes is stored in the order of goodness, and the data is transmitted by selecting the relay route with the best transmission quality at the time of data transmission (for example, see Patent Document 1).

Further, as a communication system for vehicles, a technique for wirelessly communicating between a sensor and a control unit in order to measure an air pressure inside a tire that is a rotating body is disclosed (for example,
Patent Document 2).

Japanese Laid-Open Patent Publication No. 2003-229798 (page 9, FIG. 7) JP 2003-002019 PR

As a kind of vehicle control device, for example, a state quantity to be controlled such as an operation amount of a driver with respect to a steering means such as an accelerator pedal or an air flow rate in an engine intake pipe is sensed by a sensor, and converted into an electric signal by the sensor. There is an electronic vehicle control system that transmits a sensing signal to an electronic control unit (hereinafter referred to as “ECU”) of a vehicle and controls the vehicle by an electronic control throttle or an electronic control fuel injection valve. Such an electronic vehicle control system can realize flexible and advanced integrated driving control using a computer compared to conventional transmission methods using a mechanical mechanism or hydraulic mechanism, and can reduce the weight of the vehicle. It is possible to improve the degree of freedom.

On the other hand, in a conventional vehicle control system, a signal of a sensor for monitoring an operation amount of a driver's pedal or the like or a state of the vehicle is input to an ECU through an electric wire, and is supplied to a throttle which is an actuator for vehicle control. A control signal is also output from the ECU through an electric wire. The electric wire portion from the ECU to the sensor / actuator portion is called a wire harness. Since the environment where the ECU is located is an environment where it is exposed to dust and raindrops such as the hood inside the vehicle, very high reliability is required for the connection between the wire harness and the ECU.
Pursuing reliability leads to increased component costs.

In addition, because of the wired connection, when the combination of the sensor and actuator connected to the ECU is changed, not only the control software on the ECU but also the wire harness must be changed, and there is a problem that the expandability is poor. Moreover, it is difficult to apply a wire harness to a portion that is difficult to be wired, such as a pneumatic sensor in a tire that is a rotating body. Moreover, problems such as fuel consumption deterioration due to an increase in the weight of the wire harness itself occur.

In order to solve the above problems, as described in Patent Document 2, a technique for wirelessly connecting a wire harness portion between an ECU and a sensor / actuator is known. However, in Patent Document 2, it is not considered that there are a plurality of routes regarding the relay route of the wireless communication signal. In order to improve fault tolerance, it is effective to transmit data via another relay point even if one of the relay points fails. However, the conventional wireless communication system as shown in Patent Document 1 considers the transmission of information reliably,
This is a so-called non-real-time communication system in which restrictions on time to information transmission are not severe.

Accordingly, the real-time property of data, that is, the transmission time limit is not emphasized, and as it is, it is difficult to apply to a communication system for a real-time control system such as a vehicle control system. This is because, when each communication node is controlled to use a relay route with high transmission quality (reliability) with priority, communication data is concentrated on a relay route with good transmission quality. Due to congestion, the possibility of delay in communication using this relay route increases. In the case of a vehicle control system, the congestion on the wireless communication path is a major problem because there are some demands on real-time performance, such as when the brake pedal is depressed, the brake must operate within a short period of time. It becomes. As above
In the conventional wireless communication system, there is a problem that it is difficult to achieve both reliability related to communication such as transmission quality and real-time performance (immediate response).

An object of the present invention is to solve the above-described problems and provide a vehicle control wireless communication system capable of achieving both communication reliability and real-time performance.

A transmission node for transmitting vehicle control data including at least one of a sensor measurement value for measuring a vehicle state or a driver's operation and an actuator control target value for controlling the vehicle; and the vehicle control data A plurality of wireless communication systems that satisfy a communication time limit of the transmission data, the communication system for vehicle control having a plurality of wireless communication paths between the transmission node and the reception node. The above-described problem is solved by selecting a wireless communication path from the transmission node to the reception node that satisfies the required reliability of the transmission data.

ADVANTAGE OF THE INVENTION According to this invention, the load in a wireless transmission line can be disperse | distributed by selecting the wireless communication path by making the reliability required for data correspond to the reliability of the wireless communication path, and the wireless for vehicle control Real-time (immediate response) reliability in wireless communication in a communication system can be ensured.

It is a figure which shows the structural example of the radio | wireless communications system for vehicle control by one embodiment of this invention. It is a figure which shows the specific structural example of the radio | wireless communications system for vehicle control by this Embodiment. It is a schematic diagram of the communication node (actuator and ECU) in the radio | wireless communications system for vehicle control by this Embodiment. It is a schematic diagram of the communication node (sensor) in the radio | wireless communications system for vehicle control by this Embodiment. It is a figure which shows the structural example of an engine control part and BR> wireless communication system. It is a figure which shows the attribute information of transmission data. It is a figure which shows a response | compatibility with request | requirement reliability and an allowable failure rate. It is a flowchart figure which shows the flow of a starting process of a server node. It is a flowchart figure which shows the flow of a data transmission process. It is a figure which shows the outline | summary of the evaluation / selection process of a communication path. It is a figure which shows the structural example of the radio | wireless communications system of the engine control part from which the path | route was selected by the radio | wireless communication system technique for vehicle control by this Embodiment. It is a figure which shows the example of an outline | summary of a protocol change process. It is a figure which shows the outline | summary of a signal strength change process. It is a figure which shows the format of transmission data. It is a flowchart figure which shows the flow of a data transmission process. It is a flowchart figure which shows the flow of a data reception process. It is a flowchart figure which shows the flow of a wireless communication path | route state check process. It is a figure which shows the structural example of the radio | wireless communications system for vehicle control by another Example of this invention. It is a figure which shows the outline | summary of the communication system which uses radio | wireless communication and power line conveyance together.

A vehicle control wireless communication system according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an outline of a system configuration example of a vehicle control wireless communication system according to an embodiment of the present invention. As shown in FIG. 1, the wireless communication system according to the present embodiment includes a first transmission node (Node 1) 10 and a second transmission node (Node 2) 2.
0, a receiving node (NodeN) 30, and a communication path 40. The number of transmitting nodes and receiving nodes is exemplary. Generally, at least one sensor is provided in one node.

As shown in FIG. 1, the first transmission node 10 includes transmission data 11, path evaluation means 12 for evaluating the reliability and communication time of a communication relay path, and reliability required for the transmission data 11. Is configured to include a data reliability setting unit 13 for setting the communication data, and a data / path correspondence means 14 for selecting a communication relay path corresponding to the transmission data 11. In the first transmission node 10, “high” is set as the reliability in the data reliability setting unit 13. The wireless communication path 40 generally includes one or more relay nodes. However, direct communication not via a relay node is also included. In the example illustrated in FIG. 1, the wireless communication path 40 includes a wireless communication path 41 with high reliability, a wireless communication path 42 with medium reliability, and a wireless communication path 43 with low reliability.

The first transmission node 10 uses its own route evaluation means 12 to evaluate the communication time and reliability of the communication relay route 40. Using the data / path correspondence means 14, data reliability setting is selected from a plurality of wireless communication paths (indicated by reference numerals 41 to 43 in FIG. 1) that satisfy the communication time limit set in the transmission data 11. The wireless communication path 41 with high reliability which is a path satisfying the reliability set in the unit 13 is selected. Then, the first transmission node 10 transmits the transmission data 11 to the reception node 30 using the wireless communication path 41.

The second transmission node (Node 2) 20 includes transmission data 21, route evaluation means 22 for evaluating the reliability and communication time of the communication relay route, and data reliability for setting the reliability required for the transmission data. Setting unit 23 and data for selecting a wireless communication path corresponding to transmission data
Route correspondence means 24. In the data reliability setting unit 23, the reliability “medium” is set.

The second transmission node 20 uses the path evaluation unit 22 to evaluate the communication time and reliability of the wireless communication path 40 including the relay node of the wireless communication path 40. Then, using the data / route correspondence means 24, a route satisfying the reliability set in the data reliability setting unit 23 out of a plurality of wireless communication routes satisfying the communication time limit set in the transmission data 21 The communication path 42 with the reliability “medium” is selected. Then, the transmission node 20 transmits the transmission data 21 to the reception node 30 using the wireless communication path 42.

By adopting the above configuration, the wireless communication route is a route that satisfies the communication request time and corresponds to the reliability set in the transmission data, that is, it is commensurate (so as not to concentrate on a high one). The reliability of the wireless communication path can be selected. By making such a selection, the communication load can be distributed in the wireless communication network without concentrating the communication on the highly reliable wireless communication path, and the immediate response (real time) of the communication is ensured. I can do it.
In other words, even if it was a wireless communication path that met the communication time at the time of evaluation,
When load distribution control is not performed as in the wireless communication technique according to the present embodiment, there is a risk that communication will be concentrated on a wireless communication path with load and communication delay based on congestion may occur. The radio communication technique according to the present embodiment performs load distribution paying attention to the reliability of transmission data, and is suitable for a vehicle control system that requires high reliability and real-time performance.

FIG. 2 is a diagram illustrating a more specific configuration example of the vehicle control wireless communication system according to the present embodiment. As shown in FIG. 2, the wireless communication nodes 101 to 105 constitute a wireless communication subsystem related to the engine / transmission unit 310. Wireless communication nodes 101-1
During the period 05, wireless communication with each other is possible. As for the power source, the main battery 50 and the sub-battery 5 are used for the battery in order to avoid a power cut-off / uncontrollable state due to failure.
1 has a configuration in which a minimum power supply is ensured even if an abnormality occurs in one function. Regarding the power lines, the main power line 52 and the engine transmission unit sub power network 54 are ring networks, and the power lines 53 connecting the main power network and the sub power network are two.
By employing a heavy system, power can be sent even if one power line is damaged. Note that the power line is not connected to all wireless communication nodes, but is connected only to nodes that consume a large amount of power, such as an ECU that performs control amount calculations and an actuator node that controls actuators. Sensor nodes that perform sensor processing, etc.
For nodes with low power consumption, a power line is not required by a self-power generation method using a vibration power generation element, a thermoelectric generation element, or the like.

The vehicle interior, the right front wheel, the left front wheel, the right rear wheel, the left rear wheel, etc. also form a sub-network, and these other sub-networks have the same configuration as the engine transmission sub-network. .

FIG. 3 is a diagram illustrating a configuration example of the actuator node or the ECU according to the present embodiment. The actuator node 10-1 includes an antenna 15 for wireless communication, a wireless communication unit 16,
The computer 17 which controls an actuator, the actuator 18-1 for controlling a vehicle, and the power supply part 19-1 are provided. In the case of an ECU, the actuator 18-
1 is arbitrarily provided.

FIG. 4 is a diagram illustrating a configuration example of a sensor node. As shown in FIG.
2 includes a wireless communication antenna 15, a wireless communication unit 16, a computer 17 that processes sensor signals and calculates transmission data, a sensor 18-2 for measuring a vehicle state or a driver's operation, an engine Power generation element 19 for generating power using vibration and heat generated from
-2 and a battery 19-3 for storing electric power.

With this configuration, communication between the ECU, the actuator node, and the sensor node is possible, and it is possible to reduce component costs, reduce the weight of components, and improve ECU extensibility. In other words, the ECU need only have a power line to the power grid, and no communication line is required.
There is an effect that there is no hardware restriction on the actuator configuration. further,
Since the sensor node does not require a power line, the power line does not get in the way even if it is installed on a rotating body, so that it can be easily attached to a moving body such as a rotating body.

FIG. 5 is a diagram illustrating a configuration example of a wireless communication subsystem in the engine unit. As shown in FIG. 5, the wireless communication system in the engine unit includes a vehicle 300, an engine 310,
Spark plug 311, intake pipe 312, exhaust pipe 313, wired trunk communication bus 320, intake air temperature sensor node 101, intake air amount sensor node 102, crank angle sensor node 103, and exhaust oxygen concentration sensor node 104 and an engine ECU 105. The sensor nodes 101 to 104 send the measured sensor information to the engine ECU 105.
Send to. By the way, in the structure shown in FIG.
Between the engine ECU 105 and the intake air amount sensor node 102 and the engine ECU 105
Between the two, a spark plug 311 is installed. The spark plug 311 is a very strong noise generation source. Therefore, it is necessary to perform wireless communication bypassing the spark plug 311.

The engine ECU 105 is a server of a wireless communication subsystem in the engine.
The communication path is set. Note that the engine ECU 105 needs to communicate with other brake ECUs and vehicle interior ECUs (not shown), but because of the large distance and the large amount of communication, for example, a wired connection such as CAN or FlexRay. A type communication means 320 is used.

FIG. 6 is a diagram showing an example of an evaluation table used when a route of transmission data included in the engine ECU is selected. The intake air temperature is necessary for control, but even if there is an error, there is no direct harm to the passenger, so the required reliability is B. In general, the temporal change is slow, so the transmission time limit is 100 ms. In the route evaluation formula, the route evaluation value F is calculated using coefficients kB and mB specific to the intake air temperature.

The intake air amount is data necessary for control, and if there is an error, it may lead to engine runaway. Therefore, the required reliability is A, and the temporal change is fast, so the transmission limit time is 10 ms. . Further, the route evaluation formula calculates the weight of the route evaluation value F using the coefficients kA and mA specific to the intake air temperature as shown in the figure.

FIG. 7 is a diagram showing an example of the required reliability shown in FIG. The required reliability A is, for example, a failure rate allowed for control even when a communication error occurs is 10 ⁻¹² . The required reliability B is
Even if a communication error occurs, the failure rate allowed for control is, for example, 10 ⁻⁹ . Required reliability C
The failure rate allowed for control even when a communication error occurs is, for example, 10 ⁻⁶ . Thus, the allowable failure rate is classified into A to C according to a certain threshold value.

FIG. 8 is a flowchart showing a flow of activation processing executed when the engine ECU 105 is activated. As shown in FIG. 8, first, when the ECU is activated, the process starts from step S11 (START). In step S12, it is checked whether a route is set. If a route has been set (Yes), the process proceeds to step S13. If no route is set (No), such as immediately after shipment from the factory, after initialization processing at the service factory, or when route information is lost for some reason, the process proceeds to communication route setting processing step S15. In step S13, the communication network operates according to the set route by performing inquiry communication regarding whether or not normal operation is possible from the ECU 105 to the communication node, or communication status with other nodes. Verify whether or not. In step S14, step S1
If there is no abnormality in the path as a result of the operation verification of No. 3 (Yes), the process proceeds to step S16 and the activation process ends. If there is an abnormality in the route (No), the process proceeds to step S15 to perform a communication route setting process. Hereinafter, the communication path setting process step S15 will be described in detail.

FIG. 9 shows details of the communication path design processing step S15. The process starts from step S151 (START). In step S152, the communication state information obtained in step S13 is used to search and evaluate whether there is a path that satisfies the transmission time and the required reliability set for each transmission data. The route search / evaluation will be described in detail later. Step S1
If the communication path can be set at 53 (YES), the process proceeds to step S154. If the communication path cannot be set (NO), the process proceeds to step S155. In step S155, it is verified whether or not the required reliability of the transmission data can be satisfied by changing the signal strength and the communication protocol (such as an error correction method). If it can be changed to satisfy (YES), the process proceeds to step S156, and if not (NO), the process proceeds to step S157. In step S156, signal strength / protocol change processing is performed, and in step S157, data reliability change processing is performed. The signal strength / protocol change processing and data reliability change processing will be described later. In step S154, the set path is stored in a nonvolatile memory such as an EEPROM or a flash memory (not shown). In step S158, the set route is sent to each communication node, and notification is made to use the route set at the time of data transmission. In step S159, the communication path setting process ends (END).

FIG. 10 is a diagram showing an outline of the communication route search / evaluation process performed in step S152. From route Nos. 1 to 3, the intake air temperature sensor node 101 shown in FIG.
This is a communication path candidate to the node 105. The data transmitted by the intake air temperature sensor node 101 is the intake air temperature, the required reliability is B, and the communication limit time is 100 ms.

The route No 1 communicates by a route 215 that directly communicates from the transmission node 101 to the reception node 105. In this case, since the path sandwiches the spark plug 311, the signal strength is reduced by the noise generated by the spark plug 311 and becomes the strength C. Note that the communication protocol uses a protocol having a high error correction function such as CRC and rank A. As a result, the communication path reliability evaluation is C, and the communication time is 5 ms.

The route No. 2 communicates from the transmission node 101 to the reception node 105 via the relay node 103. A path 213 from the transmission node 101 to the relay node 103 has a signal intensity A because there is no noise generation source. The communication protocol is A rank. Relay point 103
Its own failure rate is very low and rank A. Relay node 103 to receiving node 1
The route 235 to 05 is rank A in both signal strength and protocol. As a result, the communication path reliability evaluation is A, and the communication time is 10 ms.

Route No 3 communicates from the transmission node 101 to the reception node 105 via the relay node 104. A path 214 from the transmission node 101 to the relay node 104 has a signal strength A because there is no noise generation source. However, the protocol is a communication protocol having only an error check function such as a checksum and is ranked B. The failure rate of the relay point 104 itself is relatively low and rank B. The route 245 from the relay node 104 to the receiving node 105 is
Signal strength A, protocol is rank B. As a result, the communication path reliability evaluation is B,
The communication time is 10 ms.

Based on the above results, the route No. 3 that satisfies the route reliability and communication time is selected as the route for the intake air temperature sensor node 101 to transmit the intake air temperature data. At this time, the route No. 2 also satisfies the route reliability / communication time, but the reliability higher than the request is satisfied, and data for which higher reliability is required is the route No. 2 as the route. In order to leave room for selecting 2, route No. 3 is selected.

Routes No. 4 to 6 are communication route candidates from the intake air amount sensor node 102 to the ECU node 105. The data transmitted by the intake air amount sensor node 102 is the intake air amount, the required reliability is A, and the communication time limit is 10 ms. Route No. 4 is the transmission node 10
2 to the receiving node 105 through a path 225 for direct communication. In this case, since the path sandwiches the spark plug 311, the signal strength is reduced by the noise generated by the spark plug 311 and becomes the strength C. The protocol is a rank A using a protocol having a high error correction function such as CRC. As a result, the communication path reliability evaluation is C, and the communication time is 5 ms.

The route No. 5 communicates from the transmission node 102 to the reception node 105 via the relay node 103. A path 223 from the transmission node 102 to the relay node 103 has a signal intensity A because there is no noise generation source. The protocol is A rank. The failure rate of the relay point 103 itself is very low and rank A. Relay node 103 to receiving node 105
The route 235 to reach is rank A for both signal strength and protocol. As a result, the communication path reliability evaluation is A, and the communication time is 10 ms.

Route No 6 communicates from the transmission node 102 to the reception node 105 via the relay node 104. A path 224 from the transmission node 102 to the relay node 104 has a signal strength A because there is no noise generation source. However, the protocol is a protocol having only an error check function such as a checksum and is ranked B. The failure rate of the relay point 104 itself is relatively low,
B rank. A path 235 from the relay node 104 to the receiving node 105 has a signal strength A and a protocol rank B. As a result, the communication path reliability evaluation is B, and the communication time is 10 ms. As a result, the route No. 5 that satisfies the route reliability / communication time is selected as the route for the intake air amount sensor node 102 to transmit the intake air amount data.

FIG. 11 is a diagram showing a route of the wireless communication subnetwork set as described above. Data is transmitted from the intake air temperature sensor node 101 to the ECU node 105 via a route 214 and a route 245. Data is transmitted from the intake air amount sensor node 102 to the ECU node 105 via a route 223 and a route 235.

In this way, by applying the load distribution control technique according to the present embodiment, it becomes possible to select a wireless communication path in correspondence with the reliability required for transmission data and the reliability of the wireless communication path, In the vehicle control wireless communication system, both real-time performance and reliability can be achieved.

FIG. 12 is a diagram showing details of the process of changing the protocol of the wireless communication path in step S156 of FIG. Here, only the route No. 3-1 that communicates from the transmission node 101 to the reception node 105 via the relay node 104 will be described. The initial state of the route is 3-1. The route 3-1 is ranked C because the protocol has no error correction function in the route 214 and the route 245, and the reliability evaluation of the communication route is C. I am not satisfied. Therefore, by changing the protocol of the route 214 and the route 245 to a protocol having a checksum function (rank B), the reliability of the communication route is improved and a route satisfying the required reliability is generated.

FIG. 13 is a diagram showing details of the process of changing the signal strength of the wireless communication path in step S156 of FIG. Here, only the route No. 3-3 for communicating from the transmission node 101 to the reception node 105 via the relay node 104 will be described. Here, the initial state of the route is 3-3. In the path 3-3, the signal strength of the path 214 is relatively weak C, and the reliability evaluation of the communication path is C. Therefore, the required reliability of the transmission data can be satisfied. Absent. Therefore, the signal strength is set to A by increasing the output of the wireless communication on the route 214, the reliability of the communication route is improved, and the route satisfying the required reliability is generated.

As described above, for example, when an alternative route is used because the wireless communication route at the time of system design cannot be used due to a failure of a relay node or the like, the reliability of the alternative route is low and the required reliability of transmission data cannot be satisfied. However, there is an effect that a communication path that satisfies the required reliability can be generated by changing the signal strength and the protocol.

FIG. 14 shows a format of data transmitted and received in the vehicle control wireless communication system according to the present embodiment. D1 is the protocol information of the transmission data. D2 is the vehicle ID,
This is an ID for identifying the vehicle to which the transmission data belongs. Here, for example, by registering a vehicle-specific number such as a chassis number, it is possible to prevent erroneous reception of data transmitted and received by the wireless communication network of surrounding vehicles. D3 is communication path information, and information on what kind of relay point the transmission data reaches to the transmission destination node is registered. D4 is an error state and indicates that the reliability of the transmission data is lower than the required reliability and is transmitted. D5
Is transmission data. D6 is an error correction code, CRC, checksum, parity, etc.
It is used properly according to the required reliability of the transmission data. D7 is a destination of transmission data, and a node that should receive this data is designated. By interpreting the destination information, it can be determined whether this data should be received and processed.

FIG. 15 is a flowchart showing a flow of data transmission processing executed when the nodes 101 to 104 shown in FIG. 2 transmit data to the node 105 in the present embodiment.
This will be described with reference to FIG. The data transmission process is device driver software that operates on the computer 17 on the transmission node, and is called as a function from the framework or another control application to start the operation. The data transmission process is started from step S21 (START). First, in step S22, communication relay route information corresponding to the data to be transmitted is read. The route read out here is the communication route, protocol, signal strength, and vehicle ID notified from the ECU 105 in step S158 stored in a memory (not shown) on the node. Next, in step S23, the communication protocol and signal strength are set in the protocol information portion D1 of the transmission data, the vehicle ID is set in the vehicle ID portion D2, and the communication relay route is set in the communication route information portion D3. Next, in step S24, it is checked whether or not the data has reduced data reliability in step S157. If the reliability is not lowered (NO), the process proceeds to step S25 and data is transmitted. If reliability is low (YES)
Proceed to step S26. In step S26, information indicating that the reliability has decreased is set in the header D4 of the transmission data. In step S27, a flag indicating that the reliability has decreased is set as a return value of the function of this transmission process, and the process proceeds to step S25. In step S25, the transmission data is transferred to the wireless communication unit 16, and data is transmitted.

FIG. 16 is a flowchart showing an outline of the flow of data reception and relay processing.
When the wireless communication nodes 101 to 105 shown in FIG. 2 receive wireless communication by the wireless communication unit 16, the wireless communication nodes 101 to 105 interpret the destination information D7 in the header and determine whether or not the data is to be received. If the information indicating the own node is entered in D7, it is determined that the node should process, and the reception / relay process is started from step S31 (START). Step S32
Then, the communication path header D3 (FIG. 14) is confirmed, and it is determined whether the own node is the final point of the communication path, that is, whether it is a receiving node or a relay node (step S33). In step S33, if the own node is a receiving node, the process proceeds to (reception) step S34, and if it is a relay node, the process proceeds to (relay) step S331. In step S331, after rewriting the destination header, the communication data is transmitted to the relay destination node that is the next communication path of the own node, and the process is terminated. In step S34, using the error correction code D6,
It is determined whether or not there is an error in the received data. If reception or error can be normally restored, the process proceeds to step S35. If an unrecoverable error is detected, the process proceeds to step S341. In step S341, the data indicating the reception failure (NAK) is transmitted to the data transmission source by setting a route in the reverse order to that at the time of vehicle control data transmission, and becomes a server of the engine wireless communication subsystem. Data (NAK) indicating a reception failure to the ECU 10
The process ends. In step S35, data (A
CK) is transmitted by setting a route in the reverse order to that at the time of vehicle control data transmission. Next, in step S36, the error status header D4 is checked to determine whether the transmitted data is data with reduced reliability. If the data does not have reduced reliability, the process proceeds to step S37.
If the data has decreased reliability, the process proceeds to step S361. In step S361, it is determined whether data is received for the first time. If it is the first time, the process proceeds to step S362 and the process is terminated after a retransmission request is transmitted to the data transmission source. If it is not the first time, the process proceeds to step S363. In step S363, it is determined whether or not the data is the same as the previous (first) reception. If the data is the same, the process proceeds to step S37. If not the same data, the process proceeds to step S364 and the data is discarded. ). In step S37, a reception completion flag is set or a task for reception completion processing is activated, and the transmission data portion D5 of the received data is disclosed.

FIG. 17 is a communication path confirmation process executed by the ECU 105 periodically, when the communication load is low, or when reception failure information (NAK) is received. Starting from step S41 (START), in step S42, the ECU 105 performs communication with the communication node.
An inquiry is made as to whether the wireless communication node is operating normally and whether it is in communication with other nodes. In step S43, the process branches depending on whether there is an abnormal operation node. If there is no abnormal node (NO), the process ends. If there is an abnormal node (YES), the communication path setting process step described above is performed. After performing S15, the process ends.

As described above, the outline of the vehicle control wireless communication system according to the present embodiment has been described. However, the present invention is not limited to the above-described embodiments, and various modifications within the scope not departing from the gist of the present invention. It can be implemented in the form.

For example, as shown in FIG. 18, the power line 54 of the engine transmission radio communication subsystem unit is
You may make it connect to a sensor node. Further, in accordance with wireless communication, power line communication using a voltage amplitude in a frequency band different from the frequency band of the supplied power may be used on the power line. By using wireless communication and power line communication in combination, it is possible to multiplex in different communication methods, so the failure probability due to the same factor is reduced and reliability is improved compared to duplexing with the same method. is there.

FIG. 19 is a diagram illustrating a configuration example of a communication node when power line communication is employed in FIG.
The power supply unit 19-1 includes a power line communication unit 19-5 and performs communication in combination with the wireless communication unit 16. At this time, the power line communication may be operated only when the wireless communication unit fails.

According to the system according to the present embodiment, in a wireless communication system for vehicle control, the communication path is selected and the load is distributed by associating the reliability required for data with the reliability of the wireless communication path. This makes it possible to achieve both real-time performance and reliability of the system.

As described above, according to the vehicle control wireless communication system according to the embodiment, wireless transmission is performed by selecting a wireless communication path in association with reliability required for data and reliability of the wireless communication path. The load on the line can be distributed. Therefore, there is an advantage that real-time (immediate response) reliability in radio transmission in the radio communication system for vehicle control can be ensured.

  The present invention can be used in a vehicle control wireless communication system.

10, 20... Data transmission node, 30... Data reception node, 40.

Claims (17)

A transmission node for transmitting vehicle control data including at least one of a sensor measurement value for measuring a vehicle state or a driver's operation and an actuator control target value for controlling the vehicle; and the vehicle control data A vehicle control communication system having a plurality of wireless communication paths between the transmission node and the reception node,
Path evaluation means for evaluating reliability and communication time of the wireless communication path;
Load balancing means for selecting a wireless communication path from the transmitting node to the receiving node from among the plurality of wireless communication paths that satisfy the communication time limit of the transmission data;
Have
The load distribution means specifies a wireless communication path that satisfies the minimum required reliability of the transmission data among the plurality of wireless communication paths based on the evaluation result of the route evaluation means, and among the specified wireless communication paths The vehicle control radio communication system is characterized in that any one of is selected as a communication path.   2. The vehicle control wireless communication system according to claim 1, wherein the request reliability of the transmission data is specified as a request success rate or an allowable failure rate.   The vehicle control path according to claim 1, wherein when there is no communication path that satisfies the required reliability of the transmission data, the wireless communication path is generated so as to satisfy the required reliability of the transmission data. Wireless communication system. When there is no communication path that satisfies the required reliability of the transmission data,
The wireless communication for vehicle control according to claim 1, wherein a wireless communication path that satisfies the required reliability of the transmission data is generated by changing a wireless communication protocol to a more reliable one. system.   When there is no wireless communication path that satisfies the required reliability of the transmission data, it is possible to generate a wireless communication path that satisfies the required reliability of the transmission data by enhancing the signal strength during wireless communication. The wireless communication system for vehicle control according to claim 1, wherein the wireless communication system is a vehicle control wireless communication system. When there is no wireless communication path that satisfies the required reliability of the transmission data, the communication reliability of the transmission data is reduced, and the wireless communication path is selected to satisfy the changed required reliability,
2. The data is transmitted with information indicating that the request reliability of the transmission data has been reduced, and the transmission request source of the transmission data is notified to that effect. Wireless communication system for vehicle control. The node that has received the transmission data whose request data reliability has been reduced,
The wireless communication system for vehicle control according to claim 1, wherein the transmission data having the reduced required reliability is received a plurality of times and the reliability of the transmission data is evaluated. When the reliability of the communication node is reduced,
2. The vehicle according to claim 1, wherein the reliability of a wireless communication path including a communication node with reduced reliability is re-evaluated, and the wireless communication path is reset according to the required reliability of the transmission data. Wireless communication system for control.   When the first node finds a decrease in the reliability of the second node different from the first node, the reliability decrease information is further sent to the third node different from the first and second nodes. The vehicle control wireless communication system according to claim 1, wherein notification is performed.   The wireless communication system for vehicle control according to claim 1, wherein communication between nodes is performed together with power line carrier communication using a power supply line.   11. The vehicle control wireless communication system according to claim 10, wherein communication between nodes is performed by power line carrier communication using a power supply line when wireless communication is abnormal. The load balancing means includes
The radio for vehicle control according to claim 1, wherein a radio communication path from the transmission node to the reception node is selected based on the required reliability of the transmission data and the reliability of the radio communication path. Communications system.   The wireless communication route for vehicle control according to claim 12, wherein a wireless communication route candidate having a lower value is selected as to the reliability of the wireless communication route candidate as long as the required reliability of the transmission data is satisfied. system.   The wireless communication system for vehicle control according to claim 12, wherein the reliability of the wireless communication path and the required reliability of the transmission data are classified based on a threshold value evaluated in advance. The reliability of the wireless communication path is
13. The vehicle control wireless communication system according to claim 12, wherein the vehicle control wireless communication system is calculated based on at least one of a failure rate of the relay node and a communication parameter including a communication protocol or communication strength.   The wireless communication path reliability and the transmission data request reliability are classified into a plurality of groups, and the transmission data request reliability group is associated with a selectable reliability group of the wireless communication path, and data The vehicle control wireless communication system according to claim 12, wherein the transmission route is selected.   An evaluation calculation formula for evaluating the communication path from the required communication time and the reliability of the wireless communication path is set corresponding to the transmission data, and a communication path having a high evaluation score calculated by the evaluation calculation formula is selected. The vehicle control wireless communication system according to claim 12.

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