JP2009266191A - Communication method in vehicle and communication system in vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication method in vehicle and a communication system in vehicle which reduce communication traffic volume. <P>SOLUTION: The communication system 1 in vehicle includes a CAN 20, a cooperative integrated control ECU 10, a device (A) 31, a device (B) 32, and a device (C) 33. A sensor (not shown) detects a force vector applying to a tire 40. The cooperative integrated control ECU 10 represents the force vector with the angle θ and size of the force vector, and transmits the data to the device (A) 31, the device (B) 32 and the device (C) 33 through the CAN 20. The device (A) 31, the device (B) 32 and the device (C) 33 restore and use information of the force vector applying to the tire 40 (refer to Fig.6) with a format composed of the size of the force vector (resultant force) and the angle of the force vector as they are or after converting the transmitted data into a format composed of component force in an X direction and component force in a Y direction orthogonally. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an in-vehicle communication method and an in-vehicle communication system that reduce the amount of communication.

A large number of various types of electronic / electrical devices are mounted on a commercial vehicle, and these electronic / electrical devices are controlled by an ECU (electronic control unit). The ECUs are connected to each other by an in-vehicle network conforming to a CAN (Controller Area Network) standard and the like, and data is transmitted and received. Some in-vehicle electronic / electrical devices detect and control the behavior of the vehicle.
ECUs are equipped with more power train systems, such as engine controls, and body systems, such as air conditioner controls, because the control content has become sophisticated and the number of devices to be controlled has increased. The number of ECUs mounted per vehicle was about 30 from 1992 to around 1993, but now reaches 50 to 60.

  Conventionally, there is known a “vehicle control device” in which a tire vector generated in each wheel is determined as a component in a local coordinate system fixed to a vehicle body in order to determine a target state quantity of a vehicle (for example, Patent Document 1). reference). In this local coordinate system, a vector is represented by an X component, a Y component, and a Z component having directions that intersect each other.

JP 2006-51922 A (paragraphs [0154] to [0159], FIGS. 8 to 10)

However, since a very large force may be applied to the tire, the X component, the Y component, and the Z component of the vector may be very large in such a local coordinate system. For this reason, in the “vehicle control device” (described in Patent Document 1), it is necessary to secure a large value (number of digits) to represent the tire vector and transmit these plural component data. There was a problem that the amount became large.
The present invention has been made in view of such circumstances, and an object thereof is to provide an in-vehicle communication method and an in-vehicle communication system that reduce the communication amount.

  In order to solve the above problems, the present invention detects (or estimates) a force vector applied to (or applies to) a tire, expresses the force vector by its angle and its magnitude, The size is transmitted.

  According to this configuration, the force vector applied to (or applied to) the tire is expressed by the angle and the magnitude thereof. Since this angle takes a value within a finite range (0 ° or more and less than 360 °), the angle is small compared to the case where the force vector applied to the tire is expressed by the magnitude of the X component force and the magnitude of the Y component force. The force vector can be expressed by the amount of data.

  ADVANTAGE OF THE INVENTION According to this invention, when communicating the data of the force added to a tire in a vehicle, communication amount can be reduced.

  Next, an embodiment and a comparative example according to the present invention will be described in detail with reference to the accompanying drawings. Note that elements having substantially the same configuration are denoted by the same reference numerals, and redundant description thereof is omitted.

<Embodiment according to the present invention>
FIG. 1 is a block diagram showing an in-vehicle communication system 1 according to an embodiment of the present invention.
The in-vehicle communication system 1 includes a CAN (Controller Area Network) 20, a cooperative / integrated control ECU 10, a device (A) 31, a device (B) 32, and a device (C) 33. The case where the in-vehicle communication system 1 is constructed in a four-wheeled vehicle (not shown) will be described. By increasing or decreasing the types of data described later according to the number of wheels, the vehicle communication system 1 can be applied to vehicles other than four-wheeled vehicles. The in-vehicle communication system 1 can be similarly constructed.

  The CAN 20 is a communication network that mediates communication between components connected to the CAN 20 using a predetermined protocol. In this embodiment, CAN is adopted as the in-vehicle network, but a communication network based on another standard may be used. For example, other communication protocols can be used, the transmission system can be a serial transmission system or a parallel transmission system, and the network topology can be a ring type or a network type in addition to a bus type.

The device 30 is connected to the CAN 20 and is controlled by the cooperative / integrated control ECU 10. For example, the device 30 receives a signal (data) representing a force vector applied to the tire 40 (described later with reference to FIG. 2) as a control instruction value from the cooperative / integrated control ECU 10, and this control instruction value (force vector). Control is performed based on The device 30 is typically an ECU, and has a function of controlling mounted equipment (not shown) such as a power train system, a chassis system, and an electrical system of a vehicle. Specifically, for example, a brake ECU or an EPS (electric power steering) ECU that operates each actuator. Alternatively, the device 30 may be a controlled device itself.
When any one of the device (A) 31, the device (B) 32, and the device (C) 33 is shown without distinction, and when these are collectively referred to, the device 30 is referred to. Although the case where there are three devices 30 (device (A) 31, device (B) 32, and device (C) 33) will be described, the number of devices 30 may be larger or smaller.

The cooperative / integrated control ECU 10 is connected to the CAN 20 and has a function of controlling the device 30 and other in-vehicle devices / in-vehicle devices. The cooperative / integrated control ECU 10 receives a signal representing a force vector acting on (or acting on) each wheel of the tire 40 (described later with reference to FIG. 2), and angle data representing the force vector and the resultant force The size data is generated and output to the device 30 via the CAN 20. Further, the cooperative / integrated control ECU 10 generates force vector data (angle data representing the force vector and combined force magnitude data) applied to the tire as a control instruction value, and sends the data to the device 30 via the CAN 20. Output. The device 30 reproduces the force vector applied to the tire as a control instruction value from the angle data representing the force vector and the magnitude data of the resultant force (or keeps the data format) and uses it for the control.

  The code | symbol which shows the flow of each data shown in FIG. 1 represents whether the 1st character is another before and after, the 2nd character is another right and left, and the 3rd character is a synthetic force or an angle, respectively. Specifically, when the first character is F, the front wheel, when R is the rear wheel, when the second character is R, the right side, when L is the left side, when there is no third character, It represents the magnitude of the combined force, and θ represents an angle. For example, “FR” represents the magnitude of the combined force applied to (or applied to) the right front wheel, and “FRθ” represents the angle of the combined force applied to (or applied to) the right front wheel.

FIG. 2 is an explanatory diagram showing the tire 40 and a force vector acting on (or acting on) the tire 40.
Sensors (not shown) for detecting stress or acceleration acting on the tires 40 are attached to the respective tires 40, rims, axles, and suspensions (all not shown).
The magnitude of the combined force is the magnitude of the force in the direction in which the magnitude of the force vector acting in the horizontal plane including the tire 40 is maximum. The angle θ of the resultant force is an angle indicated by the direction thereof, and is a predetermined direction (for example, a direction in which the tire 40 rolls when the vehicle is moving forward or when the vehicle is advanced) in coordinates based on the vehicle body (not shown) or the tire 40 ) Is 0 °, and the angle θ is determined counterclockwise along the horizontal plane. That is, in the present embodiment, the resultant force is specified by polar coordinates composed of the angle θ and the magnitude thereof.

  Returning to FIG. 1, a vehicle acceleration sensor, an axle torque sensor for rotating each tire 40, and a sensor for detecting the steering state of the steering system are provided inside or outside the cooperative / integrated control ECU 10. The force vector applied to the tire may be calculated based on the value. Further, instead of (or in addition to) these, the force vector applied to each tire 40 is estimated based on the driving state of the power steering and engine (transmission), the behavior of the suspension, the braking state of the brake device, and the like. It is good also as a structure.

FIG. 3 is a data structure diagram showing a format example of a data block transmitted and received in the in-vehicle communication system 1, and FIG. 4 is a diagram showing numbers in the data block shown in FIG. .
In the present embodiment, one measurement value of a force vector acting on (or acting on) the tire 40 (see FIG. 2) is expressed by two data blocks. FIG. 3A shows the zeroth data block, and FIG. 3B shows the first data block. Each data block is composed of 8 bytes from 0th to 7th, and each 1 byte is composed of 8 bits from 0th to 7th. That is, the data length of one data block is 8 bytes, that is, 64 bits.

  Each bit belonging to the data block is specified by an identifier represented as ID: 0xxh. The first to third characters of this identifier are arbitrary identification values, and the fourth character h indicates hexadecimal notation. As shown in FIG. 4, each word is given a description for each assigned number. As shown in FIG. 3, each word is from MSB (Most Significant Bit) to LSB (Least Significant Bit).

For example, as shown in FIG. 4, the word with the number S1 means the magnitude of the combined force of the FR wheel, and as shown in FIG. 3, the MSB has a bit position (Bit Position) of 7 and a byte position ( Byte Position) is 0, and the LSB has a bit position of 0 and a byte position of 1. The data length of this word (number S1) is 16 bits.
Similarly, as shown in FIG. 4, the word of number S3 means an angle related to the combined force of the FR wheel, and as shown in FIG. 3, the MSB has a bit position of 7 and a byte position of 4. The LSB has a bit position of 5 and a byte position of 5. The data length of this word (number S3) is 11 bits.

  As described above, the word (numbers S3, S4) indicating the angle related to the composite force is compared with the data length of the word (numbers S1, S2, S5, S6) meaning the magnitude of the composite force being 16 bits. , S7, S8) has a data length of 11 bits, which is shorter than this. This is because there is no theoretical upper limit to the magnitude of the force vector acting on the tire 40 (see FIG. 2), and a relatively long data length (that is, a large dynamic range) is necessary to represent this with sufficient accuracy in practice. However, the angle can be expressed by a value in the range of 0 ° or more and less than 360 °, so even if the data length is slightly shorter (compared to the case of representing the magnitude of the force) This is because the value can be expressed.

In this embodiment, since the force vector (synthetic force) is expressed by the magnitude of the combined force and the angle related to the combined force in this way, a configuration in which the force vector is expressed by two component forces (described later as a comparative example). Compared with, the amount of data for representing the force vector can be reduced.
Returning to FIG. 1, since the data amount of FRθ, FLθ, RRθ, RLθ is small, the amount of communication via the CAN 20 is small, and the communication is not congested.
In the device 30, the tire 40 (FIG. 6) remains in the form of the force vector (synthetic force) magnitude and the force vector angle as data related to the force vector transmitted from the cooperative / integrated control ECU 10 as a control instruction value . The force vector information relating to the tire 40 (see FIG. 6) may be used after being restored to a form composed of orthogonal X direction component force and Y direction component force. The force vector information may be restored and used.

<Comparative example>
FIG. 5 is a block diagram showing an in-vehicle communication system 1b of a comparative example.
This in-vehicle communication system 1b has a configuration provided with a cooperative / integrated control ECU 10b instead of the cooperative / integrated control ECU 10 in the in-vehicle communication system 1 (see FIG. 1) according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a tire 40 of a comparative example and a force vector acting on (or acting on) the tire 40.
A sensor (not shown) attached to the tire 40 or the like has an X component force acting in the X direction that is the rolling direction of the tire 40 (or the traveling direction of the vehicle (not shown)) and a right angle to the X component force. The Y component force acting in the axle direction of the tire 40 (or the lateral direction of the vehicle (not shown)) is detected.

FIG. 7 is a data structure diagram showing a format example of a data block transmitted / received in the in-vehicle communication system 1b of the comparative example, and FIG. 8 shows the numbers in the data block shown in FIG. 7 in association with the description. FIG.
In this comparative example, one measurement value of a force vector acting on (or acting on) the tire 40 (see FIG. 6) is represented by three data blocks. FIG. 7A shows the zeroth data block, FIG. 7B shows the first data block, and FIG. 7C shows the second data block.
As in the embodiment according to the present invention (see FIG. 3), each data block consists of 8 bytes from the 0th to the 7th, and each 1 byte consists of 8 bits from the 0th to the 7th. That is, the data length of one data block is 8 bytes, that is, 64 bits.

For example, as shown in FIG. 8 of the comparative example, the word of number S1 means the magnitude of the X component force of the FR wheel, and as shown in FIG. 7, the MSB has a bit position of 7 and a byte position of The LSB has a bit position of 0 and a byte position of 1. The data length of this word (number S1) is 16 bits.
And the data length of the word which concerns on the magnitude | size of the X component force of each tire 40 shown by number S1-S8, and the magnitude | size of Y component force is all 16 bits.

  Thus, as shown in FIG. 3, the synthetic force acting on (or acting on) the tire 40 is compared with the case where the magnitude is represented by 16 bits and the angle is represented by 11 bits, as shown in FIG. 7. In this comparative example, regarding the resultant force acting (or acting) on the tire 40, the magnitude of the X component force is represented by 16 bits, and the magnitude of the Y component force is represented by 16 bits. For this reason, as shown in FIG. 3, in the embodiment of the present invention, two data blocks are sufficient to represent the combined force related to one measurement, whereas in this comparative example, as shown in FIG. In addition, three data blocks are required to express the resultant force related to one measurement.

1 is a block diagram illustrating an in-vehicle communication system according to an embodiment of the present invention. It is explanatory drawing which shows a tire and the force vector which acts on this (or makes it work) (this invention). It is a data structure figure which shows the example of a format of the data block transmitted / received within the in-vehicle communication system (this invention). It is a figure which shows the number in the data block shown in FIG. 3 corresponding to the description. It is a block diagram which shows the communication system in a vehicle of a comparative example. It is explanatory drawing which shows a tire and the force vector which acts on this (or makes it work) (comparative example). It is a data structure figure which shows the example of a format of the data block transmitted / received within the communication system in a vehicle of a comparative example. It is a figure which shows the number in the data block shown in FIG. 7 of a comparative example corresponding to the description.

Explanation of symbols

1, 1b In-vehicle communication system 10, 10b Cooperative / integrated control ECU (force vector expression means)
20 CAN (Transmission means)
30 devices (force vector restoration means)
31 devices (A)
32 devices (B)
33 devices (C)
40 tires

Claims (8)

Detecting a force vector applied to the tire and expressing the force vector by its angle and its magnitude;
Transmitting the angle and the magnitude;
An in-vehicle communication method comprising: Estimating a force vector applied to the tire, and expressing the force vector by its angle and its magnitude;
Transmitting the angle and the magnitude;
An in-vehicle communication method comprising: A step of representing the force vector applied to the tire as a control instruction value at the angle and magnitude of their,
Transmitting the angle and the magnitude;
An in-vehicle communication method comprising: Restoring the force vector information from the transmitted angle and the magnitude;
4. The in-vehicle communication method according to claim 1, further comprising: A force vector expressing means for expressing a force vector applied to the tire obtained through the sensor by its angle and its size;
Transmission means for transmitting the angle and the size;
An in-vehicle communication system comprising: A force vector expression means for estimating a force vector applied to the tire and expressing the force vector by the angle and the magnitude thereof;
Transmission means for transmitting the angle and the size;
An in-vehicle communication system comprising: Force vector expression means for expressing a force vector applied to a tire as a control instruction value by its angle and its size;
Transmission means for transmitting the angle and the size;
An in-vehicle communication system comprising: Force vector restoring means for restoring information of the force vector from the angle and the magnitude;
The in-vehicle communication system according to any one of claims 5 to 7, further comprising:

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