CN117148703A - CAN link control method and system based on three-mode redundancy CAN controller - Google Patents

Abstract

The invention discloses a CAN link control method and a system based on a three-mode redundancy CAN controller, wherein the system comprises: the system comprises three CAN controllers, three redundancy modules and a diagnosis module, wherein the diagnosis module presets a working mode into three independent transmission modes or redundancy modes, and the redundancy type of the redundancy modes is hot redundancy or cold redundancy; when the working mode is a three-way independent transmission mode, the diagnosis module selects three CAN controllers to establish CAN links independently; when the working mode is a redundancy mode, the redundancy module respectively receives CAN data of the two corresponding CAN controllers, and processes the CAN data and the redundancy type of the redundancy mode to obtain a processing result; the diagnosis module selects a corresponding CAN controller to establish a CAN link according to the processing result. When the redundant link is added, an additional CAN controller chip is not required to be added, and the reliability of the CAN link control system is improved.

Description

CAN link control method and system based on three-mode redundancy CAN controller

Technical Field

The invention belongs to the technical field of automobile control, and particularly relates to a CAN link control method and system based on a three-mode redundancy CAN controller.

Background

There are two conventional methods of controller area network (Controller Area Network, CAN) bus thermal redundancy. When the first is that both buses transmit data, the receiving end adopts a 'first-come-first-use' strategy, namely, the data on one bus is received when the data of any one bus arrives at the receiving node first, and the frame information of the other bus is abandoned. The data which arrives at the receiving end first may be interfered in the transmission process to generate errors, and then the data which arrives at the receiving end is accurate. In the second mode, in the system adopting the system redundancy method, the two CAN controllers are divided into a main controller and a standby controller, the main controller normally receives frame information and then sends signals to the standby controller to enable the standby controller to maintain the standby working state unchanged, when a communication link where the main controller is located fails to send signals to the standby controller due to faults, the standby controller in the working state immediately takes over the main controller, and if the communication link where the main controller sends signals to the standby controller fails, the fault state of double hosts CAN occur. Therefore, since policy consideration of selecting a failure-free bus among redundancy mechanisms is not satisfied, a more efficient redundancy mechanism is required to secure reliability of CAN communication.

In a conventional CAN bus cold redundancy mode, a timer is arranged in a control end CPU connected with a CAN controller, a main node CAN controller on the bus periodically broadcasts specific frame information to the bus, the sending period is smaller than the period of the timer, and other CAN nodes receive the frame information and then set the timers of the CPUs to zero. If the bus fails and frame information for resetting the timer cannot be received, after the timer expires, the trigger switch signal switches the standby CAN bus into the system, and the input end of the original CAN bus is shielded. The disadvantage is that the sensitivity to faults is reduced if the period of the counter is too long, and the reliability of the system is further affected; if the period is too short, the frame information of the counter reset is frequently sent, so that the utilization rate of the CAN bus is reduced, and the communication efficiency of the CAN bus is further reduced. And because of the existence of the master node, the master node needs to be additionally redundant, otherwise, when the master node fails and cannot periodically send frame information for resetting the counter, all slave devices on the bus are switched to the standby bus by mistake.

In addition, conventional CAN bus redundancy, whether cold redundancy or hot redundancy, requires adding a CAN controller chip to the original circuit design every time a redundancy path is added, which increases the area of the communication board card.

Disclosure of Invention

In order to make up the defects of the prior art, the invention provides a CAN link control method and system based on a three-mode redundancy CAN controller.

In order to solve the technical problems, the invention adopts the following technical scheme:

in a first aspect, a CAN link control system based on a triple-modular redundancy CAN controller is provided, and is applied to a vehicle-mounted FPGA chip, where the CAN link control system includes:

three CAN controllers, three redundant modules and a diagnosis module;

each redundancy module is respectively connected with the input ends of two CAN controllers, and the diagnosis module is connected with the three redundancy modules;

the diagnosis module presets the working mode as a three-way independent transmission mode or a redundancy mode, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy;

when the working mode is a three-way independent transmission mode, the diagnosis module selects three CAN controllers to establish CAN links independently;

when the working mode is a redundancy mode, the redundancy module respectively receives CAN data of the two corresponding CAN controllers, and processes the CAN data and the redundancy type of the redundancy mode to obtain a processing result;

the diagnosis module selects a corresponding CAN controller to establish a CAN link according to the processing result.

Further, the three CAN controllers are a first CAN controller, a second CAN controller and a third CAN controller respectively;

the three redundant modules are respectively a first redundant module, a second redundant module and a third redundant module;

the first redundancy module is connected with the input ends of the first CAN controller and the second CAN controller;

the second redundancy module is connected with the input ends of the second CAN controller and the third CAN controller;

the third redundancy module is connected with the input ends of the first CAN controller and the third CAN controller.

Further, the method further comprises the following steps:

a first selector, a second selector, and a third selector;

the first selector, the second selector and the third selector are all in control connection with the diagnosis module;

the first selector is connected with the first CAN controller and the CAN bus;

the second selector is connected with the second CAN controller and the CAN bus;

the third selector is connected with a third CAN controller and a CAN bus.

Further, the diagnostic module includes: a selection unit;

when the working mode is a three-way independent transmission mode, the selection unit respectively sends an opening instruction to the first selector, the second selector and the third selector, so that a first CAN link between the first CAN controller and the CAN bus is opened, a second CAN link between the second CAN controller and the CAN bus is opened, and a third CAN link between the third CAN controller and the CAN bus is opened.

Further, the diagnostic module further includes: a CAN bus data receiving unit;

the CAN bus data receiving unit receives preset flag bits through the CAN bus, and a working mode is preset according to the preset flag bits, wherein the working mode is a three-way independent transmission mode or a redundancy mode, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy.

Further, the first redundancy module, the second redundancy module and the third redundancy module have the same structure, and the first redundancy module includes:

the first data buffer area, the second data buffer area and the redundant mode acquisition unit;

the first data buffer area is connected with the first CAN controller, and the second data buffer area is connected with the second CAN controller;

the redundant mode acquisition unit is connected with the CAN bus data receiving unit;

the first data buffer area receives first CAN data of the first CAN controller, and the second data buffer area receives second CAN data of the second CAN controller;

the redundancy pattern acquisition unit acquires a redundancy type of the redundancy pattern, the redundancy type being hot redundancy or cold redundancy.

Further, the first redundancy module further includes:

the data judging unit and the redundancy comparing unit;

the data judging unit judges whether the receiving time difference of the first CAN data and the second CAN data exceeds a preset time threshold value, and if so, the first CAN data and the second CAN data are invalid; if the first CAN data and the second CAN data are not exceeded, the first CAN data and the second CAN data are valid;

when the first CAN data and the second CAN data are effective, the redundancy comparison unit performs bit-by-bit comparison on the first CAN data and the second CAN data to obtain a comparison result.

Further, the first redundancy module further includes: a redundant fault analysis unit;

the redundancy fault analysis unit is used for processing the comparison result and the redundancy type of the redundancy mode based on a preset redundancy mechanism to obtain a processing result.

In a second aspect, a CAN link control method based on a three-mode redundancy CAN controller is provided, and is applied to a CAN link control system based on the three-mode redundancy CAN controller, where the CAN link control method includes:

the diagnosis module presets the working mode as a three-way independent transmission mode or a redundancy mode, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy;

when the working mode is a three-way independent transmission mode, the diagnosis module selects three CAN controllers to establish CAN links independently;

when the working mode is a redundancy mode, the redundancy module respectively receives CAN data of the two corresponding CAN controllers, and processes the CAN data and the redundancy type of the redundancy mode to obtain a processing result;

the diagnosis module selects a corresponding CAN controller to establish a CAN link according to the processing result.

The invention has the beneficial effects that:

the CAN link control system based on the three-mode redundancy CAN controller is provided with three CAN controllers, three redundancy modules and a diagnosis module, wherein each redundancy module is respectively connected with the input ends of the two CAN controllers, and the diagnosis module is connected with the three redundancy modules; the diagnosis module presets the working mode as a three-way independent transmission mode or a redundancy mode, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy; when the working mode is a three-way independent transmission mode, the diagnosis module selects three CAN controllers to establish CAN links independently; when the working mode is a redundancy mode, the redundancy module respectively receives CAN data of the two corresponding CAN controllers, and processes the CAN data and the redundancy type of the redundancy mode to obtain a processing result; the diagnosis module selects a corresponding CAN controller to establish a CAN link according to the processing result;

the CAN controller link and the redundancy module are realized based on the FPGA, and when the redundancy link is added, an additional CAN controller chip is not needed, and only the CAN controller chip is needed to be instantiated again in the FPGA;

the CAN controller link and the redundant module in the FPGA are not dependent on specific hard IP cores in the chip, so that the CAN controller link and the redundant module are convenient to transplant among different FPGA platforms;

the cold redundancy and the hot redundancy mechanisms are realized in the redundancy module, and the software application layer only needs to call a specific function interface to read data without redundancy judgment;

the traditional thermal redundancy realization method is improved, the redundancy algorithm mechanism is realized in the FPGA, the addition of extra components in the board card is avoided, and meanwhile, the reliability of the whole system is improved.

Drawings

FIG. 1 is a block diagram of a CAN link control system based on a triple-modular redundancy CAN controller of the invention;

FIG. 2 is a block diagram of a redundancy module of the present invention;

FIG. 3 is a diagram of a redundant state transition diagram in accordance with the present invention;

fig. 4 is a flow chart of the CAN link control method based on the triple-modular redundancy CAN controller of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.

The field of application of the invention is vehicle-mounted CAN bus control, so that the CAN link control system based on the three-mode redundancy CAN controller is applied to a vehicle-mounted FPGA.

As shown in fig. 1, an embodiment of the present invention provides a CAN link control system based on a triple-modular redundancy CAN controller, including:

three CAN controllers 101, three redundancy modules 102, and a diagnostic module 103;

each redundancy module 102 is respectively connected with the input ends of two CAN controllers 101, and the diagnosis module 103 is connected with three redundancy modules 102;

the diagnosis module 103 presets the working mode into a three-way independent transmission mode or a redundancy mode, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy;

when the working mode is a three-way independent transmission mode, the diagnosis module 103 selects three CAN controllers 101 to establish CAN links independently;

when the working mode is a redundancy mode, the redundancy module 102 receives CAN data of the two corresponding CAN controllers 101 respectively, and processes the CAN data and the redundancy type of the redundancy mode to obtain a processing result;

the diagnosis module 103 selects the corresponding CAN controller 101 to establish a CAN link according to the processing result.

For convenience of the following description, three CAN controllers 101 in the embodiment shown in fig. 1 are respectively used as a first CAN controller, a second CAN controller, and a third CAN controller;

the three redundancy modules 102 are a first redundancy module, a second redundancy module and a third redundancy module respectively;

the first redundancy module is connected with the input ends of the first CAN controller and the second CAN controller;

the second redundancy module is connected with the input ends of the second CAN controller and the third CAN controller;

the third redundancy module is connected with the input ends of the first CAN controller and the third CAN controller.

Preferably, in combination with the embodiment shown in fig. 1, in fig. 1 further includes: a first selector 104, a second selector 104, and a third selector 104;

the first selector, the second selector and the third selector are all in control connection with the diagnosis module;

the first selector is connected with the first CAN controller and the CAN bus;

the second selector is connected with the second CAN controller and the CAN bus;

the third selector is connected with a third CAN controller and a CAN bus.

It should be noted that, the first selector, the second selector and the third selector are all controlled by the diagnostic module, so that the corresponding CAN controllers are connected to the CAN bus to establish the CAN link.

Preferably, the diagnostic module comprises: a selection unit;

when the working mode is a three-way independent transmission mode, the selection unit respectively sends an opening instruction to the first selector, the second selector and the third selector, so that a first CAN link between the first CAN controller and the CAN bus is opened, a second CAN link between the second CAN controller and the CAN bus is opened, and a third CAN link between the third CAN controller and the CAN bus is opened.

Preferably, the diagnostic module further comprises: a CAN bus data receiving unit;

the CAN bus data receiving unit receives preset flag bits through the CAN bus, and a working mode is preset according to the preset flag bits, wherein the working mode is a three-way independent transmission mode or a redundancy mode, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy.

Preferably, in this embodiment, the three redundancy modules have the same structure, and for convenience of specific description and illustration, a first redundancy module is described as an example, and as shown in fig. 2, the structure of the first redundancy module includes:

a first data buffer 201 and a second data buffer 202, and a redundancy pattern acquisition unit 203;

the first data buffer area 201 is connected with a first CAN controller, and the second data buffer area 202 is connected with a second CAN controller;

the redundant mode acquisition unit 203 is connected with the CAN bus data receiving unit;

the first data buffer area 201 receives first CAN data of the first CAN controller, and the second data buffer area 202 receives second CAN data of the second CAN controller;

the redundancy pattern acquisition unit 203 acquires the redundancy type of the redundancy pattern, which is either hot redundancy or cold redundancy.

Preferably, the first redundancy module further comprises:

a data judging unit 204 and a redundancy comparing unit 205;

the data judging unit 204 judges whether the receiving time difference of the first CAN data and the second CAN data exceeds a preset time threshold value, and if so, the first CAN data and the second CAN data are invalid; if the first CAN data and the second CAN data are not exceeded, the first CAN data and the second CAN data are valid; under the condition that the first CAN data and the second CAN data are invalid, the method cannot be used for subsequent processing, so that the subsequent comparison CAN only be carried out under the condition that the data are valid;

when the first CAN data and the second CAN data are valid, the redundancy comparison unit 205 performs bit-by-bit comparison on the first CAN data and the second CAN data, and a comparison result is obtained.

Preferably, the first redundancy module further comprises: a redundancy failure analysis unit 206;

the redundancy failure analysis unit 206 processes the comparison result and the redundancy type of the redundancy mode based on a preset redundancy mechanism, to obtain a processing result.

The embodiment of the invention comprises the following specific execution processes: the redundancy fault analysis unit judges whether a communication error-free link exists or not according to a processing result on the basis of a preset redundancy mechanism, and can determine whether an additional standby link is introduced or not according to the condition of hot redundancy or cold redundancy, the preset redundancy mechanism contained in the redundancy fault analysis unit is displayed by a state transition diagram, and a state machine is introduced into the FPGA according to the state transition diagram, so that the contemplated redundancy mechanism can be realized. The first CAN controller in the triple-modular redundancy is used as a working link, a state transition diagram after cold-hot redundancy is integrated is shown in fig. 3, and the meaning of each state is shown in the following table 1, wherein the number 1 CAN bus corresponds to the first CAN controller, the number 2 CAN bus corresponds to the second CAN controller, and the number 3 CAN bus corresponds to the third CAN controller.

TABLE 1 meaning of states in redundancy schema

The implementation principle of the embodiment of the invention is as follows:

the CAN link control system based on the three-mode redundancy CAN controller is provided with three CAN controllers, three redundancy modules and a diagnosis module, wherein each redundancy module is respectively connected with the input ends of the two CAN controllers, and the diagnosis module is connected with the three redundancy modules; the diagnosis module presets the working mode as a three-way independent transmission mode or a redundancy mode, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy; when the working mode is a three-way independent transmission mode, the diagnosis module selects three CAN controllers to establish CAN links independently; when the working mode is a redundancy mode, the redundancy module respectively receives CAN data of the two corresponding CAN controllers, and processes the CAN data and the redundancy type of the redundancy mode to obtain a processing result; the diagnosis module selects a corresponding CAN controller to establish a CAN link according to the processing result;

the CAN controller link and the redundancy module are realized based on the FPGA, and when the redundancy link is added, an additional CAN controller chip is not needed, and only the CAN controller chip is needed to be instantiated again in the FPGA;

the CAN controller link and the redundant module in the FPGA are not dependent on specific hard IP cores in the chip, so that the CAN controller link and the redundant module are convenient to transplant among different FPGA platforms;

the cold redundancy and the hot redundancy mechanisms are realized in the redundancy module, and the software application layer only needs to call a specific function interface to read data without redundancy judgment;

the traditional thermal redundancy realization method is improved, the redundancy algorithm mechanism is realized in the FPGA, the addition of extra components in the board card is avoided, and meanwhile, the reliability of the whole system is improved.

1-3 above, as shown in FIG. 4, an embodiment of the present invention provides a CAN link control method based on a triple-modular redundancy CAN controller, including:

401, the diagnosis module presets the working mode into three independent transmission modes or redundancy modes, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy;

402, when the working mode is a three-way independent transmission mode, the diagnosis module selects three CAN controllers to independently establish CAN links;

403, when the working mode is a redundancy mode, the redundancy module respectively receives CAN data of the two corresponding CAN controllers, and processes the CAN data and the redundancy type of the redundancy mode to obtain a processing result;

404, the diagnosis module selects a corresponding CAN controller to establish a CAN link according to the processing result.

It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The foregoing is illustrative of the present invention and is not to be construed as limiting thereof, but rather as providing for the use of additional embodiments and advantages of all such modifications, equivalents, improvements and similar to the present invention are intended to be included within the scope of the present invention as defined by the appended claims.

Claims (9)

1. The CAN link control system based on the three-mode redundancy CAN controller is characterized by being applied to a vehicle-mounted FPGA chip, and comprises:

three CAN controllers, three redundant modules and a diagnosis module;

each redundancy module is connected with the input ends of two CAN controllers respectively, and the diagnosis module is connected with three redundancy modules;

the diagnosis module presets a working mode into three independent transmission modes or redundancy modes, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy;

when the working mode is a three-way independent transmission mode, the diagnosis module selects three CAN controllers to establish CAN links independently;

when the working mode is a redundancy mode, the redundancy module respectively receives CAN data of the two corresponding CAN controllers, and processes the CAN data and the redundancy type of the redundancy mode to obtain a processing result;

and the diagnosis module selects a corresponding CAN controller to establish a CAN link according to the processing result.

2. The CAN link control system based on a triple-modular redundancy CAN controller as claimed in claim 1,

the three CAN controllers are respectively a first CAN controller, a second CAN controller and a third CAN controller;

the three redundancy modules are respectively a first redundancy module, a second redundancy module and a third redundancy module;

the first redundancy module is connected with the input ends of the first CAN controller and the second CAN controller;

the second redundancy module is connected with the input ends of the second CAN controller and the third CAN controller;

the third redundancy module is connected with the input ends of the first CAN controller and the third CAN controller.

3. The CAN link control system based on a triple-modular redundant CAN controller of claim 2, further comprising:

a first selector, a second selector, and a third selector;

the first selector, the second selector and the third selector are all in control connection with the diagnosis module;

the first selector is connected with the first CAN controller and a CAN bus;

the second selector is connected with the second CAN controller and the CAN bus;

the third selector is connected with the third CAN controller and the CAN bus.

4. The CAN link control system based on a triple-modular redundant CAN controller of claim 3, wherein the diagnostic module comprises: a selection unit;

when the working mode is a three-way independent transmission mode, the selection unit respectively sends an opening instruction to the first selector, the second selector and the third selector, so that a first CAN link between the first CAN controller and the CAN bus, a second CAN link between the second CAN controller and the CAN bus and a third CAN link between the third CAN controller and the CAN bus are opened.

5. The CAN link control system based on a triple-modular redundant CAN controller of claim 4, wherein the diagnostic module further comprises: a CAN bus data receiving unit;

the CAN bus data receiving unit receives preset flag bits through the CAN bus, and a working mode is preset according to the preset flag bits, wherein the working mode is a three-way independent transmission mode or a redundancy mode, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy.

6. The CAN link control system based on a triple-modular redundancy CAN controller of claim 5, wherein the first redundancy module, the second redundancy module, and the third redundancy module have the same structure, the first redundancy module comprising:

the first data buffer area, the second data buffer area and the redundant mode acquisition unit;

the first data buffer area is connected with the first CAN controller, and the second data buffer area is connected with the second CAN controller;

the redundancy mode acquisition unit is connected with the CAN bus data receiving unit;

the first data buffer area receives first CAN data of the first CAN controller, and the second data buffer area receives second CAN data of the second CAN controller;

the redundancy pattern acquisition unit acquires a redundancy type of the redundancy pattern, the redundancy type being hot redundancy or cold redundancy.

7. The CAN link control system based on a triple-modular redundancy CAN controller of claim 6, wherein the first redundancy module further comprises:

the data judging unit and the redundancy comparing unit;

the data judging unit judges whether the receiving time difference of the first CAN data and the second CAN data exceeds a preset time threshold value, and if so, the first CAN data and the second CAN data are invalid; if not, the first CAN data and the second CAN data are valid;

when the first CAN data and the second CAN data are effective, the redundancy comparison unit performs bit-by-bit comparison on the first CAN data and the second CAN data to obtain a comparison result.

8. The CAN link control system based on a triple-modular redundancy CAN controller of claim 7, wherein the first redundancy module further comprises: a redundant fault analysis unit;

and the redundancy fault analysis unit is used for processing the comparison result and the redundancy type of the redundancy mode on the basis of a preset redundancy mechanism to obtain a processing result.

9. A CAN link control method based on a triple-modular redundancy CAN controller, characterized by being applied to the CAN link control system based on a triple-modular redundancy CAN controller as claimed in any one of claims 1 to 8, comprising:

the diagnosis module presets a working mode into three independent transmission modes or redundancy modes, and the redundancy type of the redundancy mode is hot redundancy or cold redundancy;

when the working mode is a three-way independent transmission mode, the diagnosis module selects three CAN controllers to establish CAN links independently;

when the working mode is a redundancy mode, the redundancy module respectively receives CAN data of the two corresponding CAN controllers, and processes the CAN data and the redundancy type of the redundancy mode to obtain a processing result;

and the diagnosis module selects a corresponding CAN controller to establish a CAN link according to the processing result.