Method for supervising a computer network of a motor vehicle

Abstract

A method for supervising a computer network of a motor vehicle, said network comprising a supervisory controller connected via the network to at least one supervised controller, said method is implemented by a processor and comprises the steps of: determining (201) a recording window of a first predetermined duration, the window being sliding in time with a step of a second predetermined duration, the first predetermined duration being a predetermined multiple of the second predetermined duration; searching (205) by the supervisory controller for a control frame from the supervised controller within the step and incrementing (207) a counter if a control frame is detected such that the counter contains the number of control frames detected during the recording window;If the counter has a value greater than a first constant, then the supervisor controller considers (215) that the supervised controller is active. Figure to be published with the abbreviation: Fig 2;

Description

Title of the invention: Method for supervising a computer network of a motor vehicle technical field

[0001] The present invention relates to a method for supervising a computer network of a motor vehicle, a device for supervising a computer network of a motor vehicle, a motor vehicle comprising such a device and a computer program product. State of the art

[0002] The term “vehicle” means any type of vehicle such as a motor vehicle, a moped, a motorcycle, a warehouse storage robot, etc.

[0003] Currently, a motor vehicle includes a multitude of computers to perform various functions ranging from driver assistance functions (cruise control, lane keeping assist, etc.) to comfort functions (air conditioning, sound system, etc.) and safety functions. These computers are interconnected by computer networks using different standards. For example, some networks use the CAN (Controller Area Network) standard ISO 11898, others the LIN (Local Interconnect Network) standard ISO 17987, Ethernet, or LVDS (Low-Voltage Differential Signalling) standard TIA / EIA-644.

[0004] It is important to ensure in these networks that the connected computers function normally, in particular if they provide driving or safety functions, because they then form one or more critical systems.

[0005] To ensure the proper functioning of a critical system, it is necessary to know almost continuously the state of each computing node in order to guarantee continuity of operation in the event of a failure of one or more nodes and / or a break in one or more communication links between computing node(s), or to allow for the consideration of a functional reconfiguration need corresponding to the absence of one or more nodes.

[0006] Establishing such a state in a simple and reliable manner is associated with numerous difficulties, as it is necessary to be able to detect malfunctions that are sometimes silent and hidden in the network topology (network paths not regularly used by the operational system), depending on the network topologies, to take into account non-homogeneous latencies on the network (more or less long paths between computing nodes), and to take into account asynchronism phenomena, since all modules start asynchronously (time (different local) and their times can drift, inducing long-term cycle losses, and this avoids inducing false alarms while ensuring real monitoring with a defined latency.

[0007] Most of the proposed solutions to solve this problem are dependent on the network implementation and therefore have the disadvantage of requiring modification of the supervision as soon as the quantity of control frames on the network is modified.

[0008] There is therefore a real need for a method and a system for supervising a computer network of a motor vehicle which resolves all or part of the aforementioned disadvantages. Description of the invention

[0009] To overcome one or more of the aforementioned drawbacks, according to a first embodiment, a method for supervising a computer network of a motor vehicle, said network comprising a supervisory controller connected via the network to at least one supervised controller, said method is implemented by a processor and comprises the steps of: • determination of a recording window of a first predetermined duration, the window being sliding in time with a step of a second predetermined duration, the first predetermined duration being a predetermined multiple of the second predetermined duration; • search by the supervisor controller for a control frame from the supervised controller within the step and increment of a counter if a control frame is detected such that the counter contains the number of control frames detected during the recording window; • if the counter has a value greater than a first constant, then the supervisor controller considers that the supervised controller is active.

[0010] Thus, regardless of the implementation, the supervisor controller can know the state of the supervised controllers.

[0011] Specific features or embodiments, usable alone or in combination, are: • if the counter is less than a constant second, then the supervisory controller considers the supervised controller to be inactive; • the second constant is strictly less than the first constant; • If the monitored controller is considered active, the supervisor controller will consider it inactive at a later time if the counter becomes less than the constant second; and / or • if the supervised controller is considered inactive, the supervisor controller considers it to be active at a later time if the counter becomes greater than the first constant.

[0012] In a second embodiment, a device includes a memory associated with at least one processor configured to implement the method of the first embodiment.

[0013] In a third embodiment, a motor vehicle includes a device according to the second embodiment

[0014] In a fourth embodiment, a computer program includes instructions which, when the program is executed by the device according to the second embodiment, lead the device to implement the process according to the first embodiment. Brief description of the figures

[0015] The invention will be better understood upon reading the following description, given solely by way of example, and with reference to the figures in the appendix in which: • [Fig.1] represents a supervised computer network according to an embodiment; • [Fig. 2] represents a flowchart of a network monitoring process of [Fig. 1] according to one embodiment; and • [Fig.3] represents a temporal framework for supervision. Methods of implementation

[0016] The embodiments presented below refer to a motor vehicle, a car. However, those skilled in the art understand that they are also applicable to other types of vehicles such as vans, trucks, etc. Other applications such as a robot in a warehouse or a motorcycle on a country road are also conceivable.

[0017] Figure 1 represents an example of a computer network 101 within a vehicle. This network 101 is shown as a wired network, but could also be a wireless network. This network uses one or more of the protocols listed in the preamble.

[0018] It includes a supervisory controller 103, one of whose roles is to monitor the proper functioning of the network 101.

[0019] It also includes a plurality of supervised controllers, 105i, 1052..., 105n. These supervised controllers are used to control different functions of the vehicle as explained in the preamble.

[0020] Within the framework of the described method and supervisory device, the supervised controllers have identical functions. Therefore, the following description, for the purpose pedagogically, it initially considers that network 101 only includes a supervisory controller 103 and a supervised controller 105.

[0021] The supervisor controller 103 is used as a centralized device in charge of at least some steps of the process described below with reference to [Fig.2].

[0022] The controllers 103, 105 can take the form of a housing comprising printed circuits, any type of computer or even a mobile phone ("smartphone"). These devices are sometimes called computers or ECUs (from the English acronym "Electronic Control Unit").

[0023] The controller devices 103, 105 each include a random access memory 107 for storing instructions for the implementation by a processor 109 of at least one step of the process as described below. The device also includes a mass storage 111 for storing data intended to be retained after the implementation of the process.

[0024] They may further include a digital signal processor (DSP) 113. This DSP 113 receives data to shape, demodulate and amplify, in a manner known per se, this data.

[0025] They also include an interface 115 for the transmission / reception of data implemented by the process via the network 101.

[0026] The operation of the supervision process implemented by the network 101 and the controllers 103, 105 is as follows, [Fig.2] and [Fig.3].

[0027] In a first initialization step 201, a recording time window 301 is defined at the supervisor controller 103, having a first predetermined duration Tf. This time window 301 slides in time according to a step 303 of predetermined duration Tp. The predetermined duration Tf is a multiple K of the predetermined duration Tp, i.e., Tf = K * Tp.

[0028] The duration of the step Tp is for example 100 ms ± 10 ms and K is an integer equal for example to 20 and therefore Tf is equal to 2 s ± 0.2 s.

[0029] The supervisor controller 103 then enters network listening mode, step 203.

[0030] A listening loop is set up which evolves at the pace of the step.

[0031] During a step time Tp, controller 103 listens, step 205, the network waits from a proper functioning message M from the supervised controller 105.

[0032] If, within this interval Tp, the controller 103 receives the good operation message M, it increments, step 207, a counter C: C = C+l.

[0033] Otherwise, step 209, the counter remains at its previous value: C = C.

[0034] In parallel, controller 103 eliminates, in step 211, the state corresponding to the possible reception of message M during the oldest step associated with the recording window. Thus, in the example described, the counter C is equal to a maximum of 20 corresponding to the reception of a message M at each step associated with the recording window: C < 20.

[0035] The supervisory controller 103 then compares, in step 213, the value of the counter C with a first constant Ca. If it is greater than Ca, the supervisory controller considers, in step 215, that the supervised controller 105 is functioning normally; otherwise, it considers, in step 217, that the supervised controller is malfunctioning and it enters, in step 219, into a malfunction management process such as triggering an alarm, activating a degraded mode, etc.

[0036] Figure 1 illustrates a system according to certain embodiments. The breakdown presented is for pedagogical purposes to highlight the different functions. However, it is understood that each block can be implemented using different means or combinations thereof, such as hardware components, software, one or more computers, and / or electronic circuits. Each component may include at least one computer or a control unit. At least one memory may be included in each component. The memory may include computer program instructions or software code.

[0037] The computers can be implemented by any type of data processing device, such as a central processing unit, a signal processing unit, a specific application integrated circuit, a programmable gate network, etc. The computers can be implemented in the form of a single controller, or a plurality of controllers or computers.

[0038] The different modules are connected to each other by data links adapted to the environment. These can be wired, electrical or optical, or wireless.

[0039] For the software, the implementation may comprise modules or units distributed in the form of procedures, functions, etc. The memories may be any type of storage circuit. They may be part of the processor circuit, or separate from it and connected via electrical data links. These may be non-volatile memories, hard drives, RAM, flash memory, etc.

[0040] The software product can be downloaded from a communication network and / or stored on a computer-readable medium. It can be directly executable by a processor or be in the form of a high-level language requiring one or more intermediate operations to be executable.

[0041] Thus the program instructions stored in memory and processed by the computers can be any type of program code, for example, a compiled or interpreted program written in a suitable programming language.

[0042] The computer program instructions stored in memory are such that, when executed by the computer, the latter carries out one or more of the steps of the processes described above.

[0043] The invention has been illustrated and described in detail in the drawings and the preceding description. This description is to be considered illustrative and given by way of example and not as limiting the invention to this single description. Numerous embodiments are possible.

[0044] For example, the process has been described as a sequence of steps. Some steps can be carried out in parallel or in a different sequence.

[0045] Equations and calculations have also been detailed. The invention is not limited to the form of these equations and calculations, and extends to any other type of mathematically equivalent form.

[0046] In a first variant, a second constant Cb less than the constant Ca is defined. In the numerical example described, Ca = 15 and Cb = 5 for example.

[0047] We then consider two situations.

[0048] In the first situation, the supervised controller 105 initially operates normally. For example, the counter C is equal to 20.

[0049] Then, as the steps progress, the number of random events and steps not receiving message M increases, which causes the counter C to decrease, until the counter C becomes less than the second constant Cb, which triggers step 217 of the controller 105 malfunction state.

[0050] In the second situation, the supervised controller 105 is considered to be malfunctioning. For example, the counter C is equal to 2.

[0051] Then, as the steps progress, the number of random events and steps receiving the message M increases, which increases the counter C, until the counter C becomes greater than the first constant Ca, which triggers the functional state step 215 of the controller 105.

[0052] This variant has the advantage of stabilizing the considered state of the controller 105 and avoiding a situation of state oscillation with a counter C varying around the first constant.

[0053] In a second embodiment, the network comprises a plurality of supervised controllers. The method is then applied to each supervised controller independently of the others. For this purpose, the message M includes an identifier associated with each supervised controller, and the controller 103 includes as many counters as there are supervised controllers.

Claims

Demands

1. A method for supervising a computer network of a motor vehicle, said network comprising a supervisor controller connected via the network to at least one supervised controller, said method being implemented by a processor and comprising the steps of: • determining (201) a recording window of a first predetermined duration, the window being sliding in time with a step of a second predetermined duration, the first predetermined duration being a predetermined multiple of the second predetermined duration; • searching (205) by the supervisor controller for a control frame from the supervised controller within the step and incrementing (207) a counter if a control frame is detected such that the counter contains the number of control frames detected during the recording window;• if the counter has a value greater than a first constant, then the supervisor controller considers (215) that the supervised controller is active.;

2. A method according to claim 1, wherein, if the counter is less than a constant second, then the supervisor controller considers the supervised controller to be inactive.

3. A method according to claim 2, wherein the second constant is strictly less than the first constant.

4. A method according to claim 3, wherein, if the supervised controller is considered active, the supervisor controller considers it inactive at a later time if the counter becomes less than the second constant.

5. A method according to claim 3 or 4, wherein, if the supervised controller is considered inactive, the supervisor controller considers it to be active at a later time if the counter becomes greater than the first constant.

6. Device (103) comprising a memory associated with at least one processor configured to implement the method according to one of the preceding claims.

7. Motor vehicle comprising the device according to the preceding claim.

8. Computer program product comprising program code instructions which, when the program is executed by the device according to claim 6, cause the device to implement the method according to any one of claims 1 to 5.