Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L12/407—Bus networks with decentralised control
  • H04L12/413—Bus networks with decentralised control with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]

Definitions

• the present invention relates to a device for generating messaging common to several electronic systems producing and consuming data exchanged on a common multiplex communication bus, said data being carried by digital signal frames each comprising at least one of said data. .
• Such a vehicle commonly comprises several systems, each ensuring the execution of a service such as controlling the engine propelling the vehicle, managing the air conditioning of the passenger compartment, managing the connections of the vehicle to the ground (braking, suspension, etc.). .), management of telephone communications, etc., etc.
• a service such as controlling the engine propelling the vehicle, managing the air conditioning of the passenger compartment, managing the connections of the vehicle to the ground (braking, suspension, etc.). .), management of telephone communications, etc., etc.
• FIG. 1 of the attached drawing The material means which constitute all of these systems are shown diagrammatically in FIG. 1 of the attached drawing.
• These means essentially comprise electronic control units or "ECUs" UCE n / each computer possibly being connected to sensors C n ⁇ and to actuators A 1 "- ,, all the computers being connected to the same bus B to transmit there. or receive suitably ultiplexed information from or to the other computers connected to bus B.
• the system S 2 of "engine control” comprises the computer • UCE 2 , several sensors C 2 i sensitive to quantities such as the engine speed, for example of internal combustion, the pressure at the manifold intake of this engine, outside air pressure, engine cooling water temperature, air temperature, battery charge status, etc., etc., and several actuators 2 .
• the ECU 2 computer is duly programmed to execute several engine control functions such as: idling control, regulation of the richness of the air / fuel mixture, adjustment of the ignition advance of this mixture and recirculation exhaust gases.
• the ECU 2 computer uses information from the abovementioned sensors C z ⁇ and develops control signals for the actuators 2 j constituted by an additional air control valve and a spark plug ignition coil for the "regulation” function.
• the list of digital signal frames is called "messaging" . which, in a given vehicle, carry the data consumed or produced by each of the systems, this data being made available to . other systems on the multiplex bus which interconnects them.
• the computers of the various electronic systems are programmed to receive and transmit frames of predetermined signals.
• a basic messaging system is adapted, using calibration data stored in the computers of the various electronic systems of the vehicle.
• This messaging generation process is however not very flexible, because it requires starting from a basic messaging, predefined in the vehicle development phase, and therefore of rigid structure, using a software tool such as VOLCANO, available from the Swedish company Volcano Communication Technologies AB.
• the present invention therefore aims to provide a device for generating a messaging common to several electronic systems producing and consuming data, designed to overcome the difficulties mentioned above and, in particular, to allow the loading of such a messaging in motor vehicles progressing on the same production line, messaging of each vehicle being personalized according to the services> and / or the equipment specific to each of these vehicles.
• a device for generating messaging common to several electronic systems producing and consuming data exchanged on a bus multiplex communication interconnecting said systems, said data being carried by digital signal frames each comprising at least one of said data, this device being remarkable in that it comprises a) means for listing data potentially produced or consumed by said systems as well as the characteristics of said data, b) means for configuring the signal frames produced by each of the systems, these means comprising: bl) means for reading the content of said means for listing said data, b2) means for formatting formats said frames, on the basis of the information gathered by said reading and predetermined rules defining an architecture of said messaging conditioning the operation of the bus and said electronic systems, and c) loading means, in each. of said systems, frame formats developed by said means of constitution for the transmission of frames loaded with data produced by said system.
• this device makes it possible to optimize the structure of the messaging loaded in each vehicle, while simplifying the development process of this messaging.
• the listing means are constituted by a plurality of interface means each associated with one of said electronic systems and listing the data potentially produced or consumed by said system
• each of the electronic systems comprises an electronic control unit
• the interface means being constituted by electronic memories each associated with one of said electronic control units, said electronic memories store characteristics of said data chosen from the group formed by: the accuracy of the data, the frequency of its presentation on the bus, the identity of the control unit which produces the data, the identity of the control unit (s) which consume it, - the frame format constitution means proceed according to a heuristic method
• the device further comprises means for constituting the format of masks for the reading, by each of said systems, of the data which they consume and which are incorporated into frames produced by the other systems,
• the electronic systems are on board a motor vehicle where they are interconnected in a CAN type communication bus, the means for configuring frames or masks being incorporated into a computer placed on the edge of a motor vehicle production line, wireless communication means being installed between this computer and the bus.
• FIG. 1 is a diagram of the messaging generation device according to the present invention, already shown partially described in the preamble to this description
• FIG. 2 represents the format of a frame of digital signals representative of those generated by the device according to the invention
• FIG. 3 is a table, established by the device of FIG. 1, listing the data to be introduced into frames of digital signals formatted by this device, and
• FIGS. 4 and 5 are illustrative examples of tables, established by this device, listing the data contained in digital signal frames forming part of the messaging generated by the device according to the invention.
• FIG. 2 of the accompanying drawing shows the format of such a frame of such signals, of the well-known CAN type.
• a CAN frame thus comprises various fields, SOF field at the start of frame, EOF field at the end of frame, etc ... and, in particular, an identifier field and a data field which may contain several different data, recorded in distinct zones x, y, z, ... of this field, which has 8 bytes.
• Each frame brings together data produced by the same "node" of all the electronic systems of FIG. 1, that is to say by the same computer ECU n .
• the device comprises means MC for configuring these frames.
• these means are constituted by a computer placed, in the "automobile” application described in the preamble to this description, at the edge of a motor vehicle production line, so as to be able to interact with each of the UCE n computers on board the same vehicle, via bus B and bidirectional connection means (not shown), installed between the computer and this bus.
• these connection means are of the "wireless” type and operate on radio frequency or microwave, for example.
• the means MC for configuring the frames can read the. content of the interfaces I n of the computers of a vehicle which will leave the production line, analyze this content and build a coherent set of frame formats containing the data, the frame formats associated with each of the UCE n computers then being recorded in means F n for loading these formats associated with the respective computers (see FIG. 1), at the same time as the software means making it possible to construct these frames, or to extract relevant data from the frames accessible on the bus.
• the means MC for configuring the device essentially comprise means LI for reading the content of the interface means I n and means MF for constituting frame formats and, as will be seen further on, mask formats.
• the means LI for reading interfaces are software means which, on the basis of the information contained in the set of interface means I n associated with the computers UCE n , make it possible to form a table such as that illustrated in FIG. 3, listing all the data a, b, c, etc ... produced or consumed by the various systems of the set diagrammed in Figure 1 and, for each data, its "precision" or size, in bits, its period presentation on bus B, the identity of the computer which produces it and that (s) of the computer (s) which consumes it.
• the means MF for constituting frame formats are software means which, on the basis of the information gathered in the table of FIG. 3 by the interface reading means LI, and of rules which will be defined in the following of this description , define an architecture of the messaging system to be loaded in all of the electronic systems of FIG. 1, that is to say the formats of the various frames of data-carrying signals produced by the different "nodes" of this set, that is to say by the various ECU n computers.
• the software means MF firstly constitute lists of all the data transmitted by the same computer, then classify this data according to their period of presentation (or "production") on the bus B. Then, by a self-learning or heuristic method, the MF means ensure optimal grouping of data in frames, by the application of predetermined rules such as: each frame contains data produced by the same computer, the number of frames produced by the same computer is minimized, - the number of frames read by the same computer is minimized, the periods of presentation of the data of the same frame are identical or compatible, the lengths of the transmitted frames are balanced, as far as possible.
• FIGS. 4 and 5 bring together the characteristics of two formats of frames representative of those of the sets of frames calculated by the means MC for configuring the device according to the invention, these frames being given by way of illustrative and nonlimiting example only. .
• Each frame is named and each of the data carried by this. frame is identified by a coded number, on 16 bits for example, containing various fields identifying respectively the service of the vehicle in which the data participates, the function which uses the data and the name itself of the data.
• the frame defined by the table in FIG. 4 thus carries the data c and b from the table in FIG. 3.
• the data c is produced (P) by the calculator UCEi and consumed (C) by the calculator UCE 2 .
• Its size is 1 bit, positioned at bit 7 of byte No. 1 (see Figure 2) of the data field of the frame.
• Data b has the same characteristics except that it is positioned at bit 6 of byte No. 1.
• the frame defined by the table of FIG. 5 comprises only one data item f produced by the calculator UCE ⁇ and consumed by the calculator UCE 3 , its size is 64 bits, the most significant bit (MSB) being positioned at bit N ° 7 of byte N ° 1.
• the frame formats established by the format constitution means MF correspond to frames whose priorities are, in the case of a CAN bus, determined by the content of the identifier field of these frames.
• the allocation of priority to the various frames can be done in application of the so-called "Rate Monotony” criterion as described in the work by Klein, MH et al entitled “A Practitioner 's Handbook for Real-Time Analysis: Guide to Rate Monotonie Analysis for Real-Time Systems ", Boston, USA, MA; editor: Klu er Académie Publishers, 1993. for periodic frames, possibly with a correction made by the degree of criticality of the information conveyed by the frame.
• the frames sent following an event may have a higher priority than the others and will be hierarchical between them according to the declared criticality of the data and, possibly, according to a priority level classification by systems (engine control, air conditioning, cabin, etc.).
• the various versions of messaging calculated by the computer MC at the edge of the chain can advantageously be stored therein. So when two vehicles of the same version appear successively in front of this computer, the computer does not have to rerun, for the second vehicle, the calculations already performed when the first was passed.
• the format creation means MF first calculate, as described above, the messaging formats to be established for a given vehicle. From these formats, they then calculate mask formats. These masks are used, by each of the ECU n computers, to determine, among all the frames presented on the bus B, those which contain data which they use, then to locate on these frames the position or positions of these data in the data fields, in order to read the identified data.
• the frame formats and mask formats used by each ECU n computer are stored in the loading means of formats F n associated with this computer, these means being constituted by a read-only memory of the "E2PROM" type for example. Also stored in this memory are the software means making it possible to construct the frames and the masks, from data defining the formats thereof.
• the device according to the invention then operates as follows. Different versions of the same vehicle progress successively on a production line at the edge of which the computer MC of this device is installed.
• the various ECU computers n on board the vehicle in order to recognize it.
• each of these computers is attached a predetermined identifier, recognized by the computer.
• this identifier further defines an order of priority in the systems associated with the identified computers.
• Means can also be provided for securing communications between a vehicle and the computer, in order to prevent unwanted bus access (hacking, sabotage, etc.).
• each computer may contain a code that is executed • After previously only the launch of frame configuration and masks. This code allows the computer to respond to requests from the configuration computer MC by giving its identity, then the list of data it must receive and then that of the data it must produce.
• the computer interrogates each computer in the order defined by the priority integrated into the identifier of this computer and configures the frames and masks associated with this computer as described above. Finally, it loads the calculated configurations and the software means for constructing frames and masks from these configurations, into the associated memory F n .
• the MC computer also loads the alarms and events to be monitored into this memory.
• frame activation vectors For each frame and each data, the tables define the position of the data in the frame and the position of this same data in memory.
• the software means examine whether to send a frame. If necessary, they first of all update the frame vectors. If a data item must be sent immediately, the production of the data command sets an activation bit of the corresponding frame to "1" in the activation vector of the frames.
• the activation bit of this frame is set to 1, in the activation vector of the frames, with a corresponding frequency.
• the activation vector of the frames is traversed periodically, for example every 5 ms, to start the procedure for sending all the frames for which the activation bit is at 1 in this activation vector of the frames.
• the frame table allows you to find in memory the values of the data to be sent in the activated frames.
• the procedure can be as follows. The arrival of the frame on the bus triggering an interrupt, this interrupt triggers a task, consisting in storing the frame in a buffer memory. After reading the identifier of this frame, contained in the identifier field of this one, and reading in the vector of frames of the beginning of the corresponding table of frames, the task takes in this one the data of the frame which are to read and then write to RAM memory, to refresh the data contained therein.
• the masks making it possible to select the frames which must be used by such or such central unit UCEi are also developed by the messaging generation device according to the invention.
• the generation of messaging according to the present invention makes it possible to reduce the development time of this messaging.
• the proposed generation process can still be implemented without difficulty by progressive modifications of the current classic process, mainly occurring during the development phase.
• the present invention is not limited to the embodiment described and shown, which has been given only by way of example.
• the reading of the information on the exchanges of data stored in the interface means I n could be replaced by the prior constitution of a database gathering this information, this, however, to the detriment of the flexibility of the device according to the invention.

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• Computer Networks & Wireless Communication (AREA)
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Citations (3)

• 2001
  • 2001-04-27 FR FR0105713A patent/FR2824213B1/fr not_active Expired - Fee Related
• 2002
  • 2002-04-26 WO PCT/FR2002/001453 patent/WO2002089420A2/fr active IP Right Grant
  • 2002-04-26 DE DE60215926T patent/DE60215926T2/de not_active Expired - Lifetime

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