CN114884767A

CN114884767A - Synchronous dual-redundancy CAN bus communication system, method, equipment and medium

Info

Publication number: CN114884767A
Application number: CN202210490387.8A
Authority: CN
Inventors: 刘敏; 黄敏思
Original assignee: Guangzhou Institute Of Software
Current assignee: Guangzhou Institute Of Software
Priority date: 2022-05-07
Filing date: 2022-05-07
Publication date: 2022-08-09
Anticipated expiration: 2042-05-07
Also published as: CN114884767B

Abstract

The invention relates to the technical field of data communication, in particular to a synchronous dual-redundancy CAN bus communication system, method, equipment and medium, which comprises the following steps: the system comprises a microprocessor, a CAN transceiver module and a bus system which are connected in sequence; the microprocessor is internally provided with at least three CAN controllers, the CAN transceiver module comprises at least three CAN transceivers which are respectively a first CAN transceiver, a second CAN transceiver and a third CAN transceiver, the bus system comprises at least two CAN buses, and the second CAN transceiver and the third CAN transceiver are respectively connected with the two independent CAN buses for communication. The invention combines software and hardware to realize a synchronous dual-redundancy CAN transceiving system, solves the problems that the traditional CAN bus cannot simultaneously transmit two redundant lines, has poor synchronism, more complex software processing and low working efficiency, effectively improves the anti-interference capability of the CAN bus, and enables the CAN bus to normally work in a strong interference environment.

Description

Synchronous dual-redundancy CAN bus communication system, method, equipment and medium

Technical Field

The invention relates to the technical field of data communication, in particular to a synchronous dual-redundancy CAN bus communication system, method, equipment and medium.

Background

With the rapid development of electromotion, electric engineering machinery and electric tramcars are rapidly developed, control node buses brought by electromotion are distributed, the number of more than ten nodes of an original CAN bus system is increased to more than 60, the digitization degree of the system is improved, the length of a cable is shortened, the wiring difficulty is simplified, but the dependence of the system on the safety and the reliability of the buses is brought, namely simply 'disconnection or breakdown', therefore, in the occasions with extremely high safety, the redundancy design of the circuits is particularly important, at least 2 groups of CAN buses are required to be configured for wiring, and when one group of the nodes is damaged, external force impact and the like causes short circuit or disconnection of the circuits, the other group of the nodes CAN normally ensure the communication of data.

At present, the traditional CAN bus redundancy design is generally realized by controlling two CAN controllers and CAN transceivers through a microcontroller MCU, as shown in fig. 1, the microcontroller MCU is internally provided with two CAN controllers, each CAN controller is connected with one CAN transceiver, and then is connected to two CAN bus networks through CANH and CANL, and then performs dual redundancy sending and receiving strategy processing through the processing mode as shown in fig. 2, so as to realize data transmission, although the hardware of the traditional dual redundancy software and hardware method is simple, only two standard CAN bus circuits are needed, but the software processing is complex, and because the program of the MCU CAN only be sequentially executed, it is difficult to synchronize the sending of two sets of CAN data, the synchronization is poor, so as to bring uncertainty to redundancy judgment of the receiving node; in addition, when data is transmitted, if there is a large interference on the line, the synchronization of the two redundant channels will be affected by the error retransmission mechanism when the CAN bus is transmitted, so that the synchronization difference will be further enlarged, which brings difficulty to the redundancy judgment of the receiving node, reduces the working efficiency of the system, and at the same time, the redundant system cannot realize "hot backup", and only CAN perform "cold backup" by way of channel switching.

Disclosure of Invention

The invention provides a synchronous dual-redundancy CAN bus communication system, a synchronous dual-redundancy CAN bus communication method, synchronous dual-redundancy CAN bus communication equipment and synchronous dual-redundancy CAN bus communication media, and solves the technical problems that a traditional CAN bus cannot simultaneously transmit two redundant lines, the synchronism is poor, the software processing is complex, and the working efficiency is low.

To solve the above technical problems, the present invention provides a synchronous dual-redundancy CAN bus communication system, method, device and medium.

In a first aspect, the present invention provides a synchronous dual redundant CAN bus communication system, comprising: the system comprises a microprocessor, a CAN transceiver module and a bus system which are connected in sequence;

at least three independent CAN controllers are arranged in the microprocessor, namely a first CAN controller, a second CAN controller and a third CAN controller;

the CAN transceiver module comprises at least three CAN transceivers which are respectively a first CAN transceiver, a second CAN transceiver and a third CAN transceiver, wherein RXD pins of each CAN transceiver are correspondingly connected with RXD pins of each CAN controller in a one-to-one manner, and TXD pins of each CAN transceiver are connected in parallel with TXD pins of the first CAN controller, so that the second CAN transceiver and the third CAN transceiver synchronously receive data frames transmitted by the mirror image of the first CAN controller;

the bus system comprises at least two independent CAN buses, and the second CAN transceiver and the third CAN transceiver are respectively connected with the two independent CAN buses for communication so as to provide external redundant line output.

In a further embodiment, a first termination resistor is provided between a CANH pin and a CANL pin of the first CAN transceiver, such that the first CAN controller and the first CAN transceiver form a self-transceiving loop; wherein the first termination resistor is used for matching impedance;

the first termination resistance comprises a 60 Ω termination resistance.

In a further embodiment, a second termination resistor is disposed at both ends of a CAN bus in the bus system.

In a further embodiment, the second termination resistance comprises a 120 Ω termination resistance.

In a further embodiment, the second CAN transceiver and the third CAN transceiver are configured to transmit the data frames sent by the first CAN controller to two CAN buses respectively, and receive the data frames transmitted by the two CAN buses.

In a further embodiment, the microprocessor is configured to detect whether the first CAN controller and the first CAN transceiver successfully transmit and receive data frames, and determine whether the node is damaged according to the recorded accumulated number of failures and a preset failure threshold;

the microprocessor is further configured to detect whether at least one of the second CAN transceiver and the third CAN transceiver successfully receives a data frame, and determine whether the other CAN transceiver has the same data frame.

In a further embodiment, the number of CAN controllers is the same as the number of CAN transceivers in the CAN transceiver module.

In a second aspect, the present invention provides a synchronous dual-redundancy CAN bus communication method, including the following steps:

controlling the first CAN controller to send the data frame to each CAN transceiver in the CAN transceiver module;

detecting whether the first CAN controller and the first CAN transceiver successfully receive and transmit data frames, and judging whether the node is damaged according to the recorded fault accumulation times and a preset fault threshold value;

and detecting whether at least one of the second CAN transceiver and the third CAN transceiver successfully receives the data frame, and judging whether the other CAN transceiver has the same data frame.

In a third aspect, the present invention also provides a computer device, which includes a processor and a memory, where the processor is connected to the memory, the memory is used for storing a computer program, and the processor is used for executing the computer program stored in the memory, so that the computer device executes the steps for implementing the method.

In a fourth aspect, the present invention also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the above method.

The invention provides a synchronous dual-redundancy CAN bus communication system, a method, equipment and a medium, wherein the system is provided with at least three paths of CAN controllers and CAN transceivers, self-transceiving of data frames is realized through one path of CAN controller and CAN transceiver, and external redundant bus output is realized through the other two paths of CAN controller and CAN transceiver for completely decoupling and separating the error-detected CAN controller from the CAN controller for transmitting the data frames. Compared with the prior art, the system not only realizes synchronous sending and receiving of the data frame, but also ensures that the sending of the data frame is not interrupted by any interference, and improves the transmission stability of the CAN network and the software processing efficiency.

Drawings

FIG. 1 is a schematic diagram of a conventional dual redundant CAN bus node provided in the background of the present invention;

FIG. 2 is a schematic diagram of a conventional dual redundant CAN bus software processing flow provided by the background art of the present invention;

FIG. 3 is a schematic diagram of a conventional dual-redundancy CAN bus being out of synchronization due to local interference according to the background art of the present invention;

fig. 4 is a block diagram of a synchronous dual-redundancy CAN bus communication system according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a dual-redundancy CAN bus provided by an embodiment of the present invention being synchronized by local interference;

fig. 6 is a schematic diagram of a data transmission flow of a synchronous dual-redundancy CAN according to an embodiment of the present invention;

fig. 7 is a schematic flowchart of a synchronous dual-redundancy CAN bus communication method according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a computer device according to an embodiment of the present invention.

Detailed Description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, which are given solely for the purpose of illustration and are not to be construed as limitations of the invention, including the drawings which are incorporated herein by reference and for illustration only and are not to be construed as limitations of the invention, since many variations thereof are possible without departing from the spirit and scope of the invention.

Referring to fig. 4, an embodiment of the present invention provides a synchronous dual-redundancy CAN bus communication system, as shown in fig. 4, the system includes: the system comprises a microprocessor 10, a CAN transceiver module 11 and a bus system which are connected in sequence, wherein at least three independent CAN controllers which are a first CAN controller, a second CAN controller and a third CAN controller are arranged in the microprocessor 10; the CAN transceiver module 11 comprises at least three CAN transceivers, namely a first CAN transceiver, a second CAN transceiver and a third CAN transceiver, the number of the CAN controllers is the same as that of the CAN transceivers in the CAN transceiver module, and each CAN controller is connected with one CAN transceiver.

In this embodiment, an RXD pin of each CAN transceiver is connected to an RXD pin of each CAN controller in a one-to-one correspondence, and a TXD pin of each CAN transceiver is connected to a TXD pin of the first CAN controller in parallel, so that the second CAN transceiver and the third CAN transceiver synchronously receive a data frame sent by the mirror image of the first CAN controller.

Specifically, a TXD pin of the first CAN controller is connected to a TXD pin of a first CAN transceiver, an RXD pin of the first CAN controller is connected to an RXD pin of the first CAN transceiver, and a first termination resistor is arranged between a CANH pin and a CANL pin of the first CAN transceiver, so that the first CAN controller and the first CAN transceiver form a self-transceiving loop; in this embodiment, the first termination resistance comprises a 60 Ω termination resistance; it should be noted that, as shown in fig. 5, the self-transceiving loop formed by the first CAN controller and the first CAN controller is equivalent to a board-level closed security microenvironment, and in this environment, any error does not occur in sending the CAN data frame, and the entire data frame CAN be completely transmitted.

In the embodiment, a self-transceiving loop is formed by the first CAN controller and the first CAN transceiver, CAN message transmission of the node is realized, and the node is simply transmitted in the onboard self-transceiving loop, so that the interference on a CAN bus is avoided, and the problem of transmission error is avoided.

The TXD pin of the first CAN controller is also connected in parallel to the TXD pins of the second CAN transceiver and the third CAN transceiver which are output to the outside through a line, so that the signals converted into differential CANH and CANL through the second CAN transceiver and the third CAN transceiver are accessed into an actual redundant first CAN bus and an actual redundant second CAN bus, and the complete synchronous sending of CAN sending messages and the receiving of two redundant buses are realized, namely, the message waveform timestamps sent to the CAN line 1 and the CAN line 2 are completely consistent; and simultaneously, an RXD pin of the second CAN controller is connected with an RXD pin of the second CAN transceiver, and an RXD pin of the third CAN controller is connected with an RXD pin of the third CAN transceiver.

It should be noted that in this embodiment, the TXD pins of the second CAN controller and the third CAN controller are not connected to any other pin, so as to ensure that the other CAN controllers except the self-transceiving CAN controller cannot send out an error frame to interrupt transmission, as shown in fig. 5, when the second CAN controller and the second CAN transceiver encounter interference in the transmission process, the self-transceiving processes of the first CAN controller and the first CAN transceiver are completely independent and are not interfered by the other CAN controllers and the CAN controllers, but the second CAN controller CAN monitor an error and send an error frame to interrupt transmission of the second CAN controller and the transceiver according to the CAN rule by sending the error frame through the TXD pin, because the TXD pin of the second CAN controller is not connected in this embodiment, the transmission of the error frame is not interrupted, so that a situation that all nodes receive an abnormal message due to a local error of the CAN bus is avoided, meanwhile, retransmission of the sending node due to errors is avoided, and therefore the time certainty of message sending is guaranteed, the CAN1 in fig. 5 represents a first CAN transceiver module composed of a first CAN controller and a first CAN transceiver, the CAN2 represents a second CAN transceiver module composed of a second CAN controller and a second CAN transceiver, and the CAN3 represents a third CAN transceiver module composed of a third CAN controller and a third CAN transceiver.

In this embodiment, at least three CAN controllers are used to decouple the RXD pin for error detection from the TXD pin for transmission in the CAN controller, so as to ensure that the first CAN controller is not interrupted by any interference during transmission, complete transmission in a "clean" environment, and implement self-transmission and self-reception of data frames through the first CAN transceiver, and implement mirror image transmission of data frames through the second CAN transceiver and the third CAN transceiver.

The bus system comprises at least two independent CAN buses which are respectively a first CAN line and a second CAN line, and the second CAN transceiver and the third CAN transceiver are respectively connected with the two independent CAN buses for communication so as to realize the output of external redundant lines.

In this embodiment, the CANH pin and the CANL pin of the second CAN transceiver are connected to the first CAN line, and the CANH pin and the CANL pin of the third CAN transceiver are connected to the second CAN line.

In one embodiment, two ends of a CAN bus in the bus system are provided with second terminal resistors; the second termination resistor includes a 120 Ω termination resistor, and as shown in fig. 4, 120 Ω termination resistors are disposed at two ends of the first and second CAN lines.

In one embodiment, the microprocessor is configured to detect whether the first CAN controller and the first CAN transceiver successfully receive and transmit data frames, and determine whether the node is damaged according to the recorded accumulated number of failures and a preset failure threshold; and the CAN transceiver is also used for detecting whether at least one of the second CAN transceiver and the third CAN transceiver successfully receives the data frame or not and judging whether the other CAN transceiver has the same data frame or not.

Specifically, as shown in fig. 6, after controlling the first CAN controller to send a data frame, the microprocessor determines whether the first CAN controller and the first CAN transceiver successfully send and receive the data frame, if so, sends the next data frame, if not, records the accumulated failure times, and determines whether the node is damaged according to the accumulated failure times and a preset failure threshold, that is, when the accumulated failure times exceed the preset failure threshold, determines that the node is damaged, writes a failure code into the database, and prompts a worker to maintain; when the accumulated failure times are lower than a preset failure threshold value, sending a next data frame; it should be noted that, the failure threshold is preferably set to 32 in the present embodiment, and those skilled in the art can adjust the failure threshold according to the specific implementation.

Meanwhile, the microprocessor judges whether at least one of the second CAN transceiver and the third CAN transceiver successfully receives the data frame, and if not, the microprocessor returns to re-detection; if so, judging whether the other CAN transceiver has the same data frame, and emptying the data buffer of the CAN transceiver with the same data frame when judging that the other CAN transceiver has the same data frame.

In this embodiment, when all nodes in the CAN bus system adopt the synchronous dual-redundancy CAN bus communication system, messages on two redundant buses are necessarily completely synchronous, a receiver does not need to perform time difference judgment waiting, and CAN use the messages immediately as long as any CAN line receives the messages, and does not need to pay attention to whether the other line receives the messages, so that the time of redundancy waiting in the traditional design is greatly saved, and the bandwidth utilization rate of the system is improved.

The synchronous dual-redundancy CAN bus communication system provided by the embodiment of the invention realizes a fully synchronous dual-redundancy CAN transceiving system by the microcontroller provided with at least three CAN controllers and the CAN transceivers connected with each CAN controller in a one-to-one correspondence manner; meanwhile, a self-transceiving loop is formed by the first CAN controller and the first CAN transceiver, so that the problem of redundant line time difference caused by error retransmission of the CAN bus is avoided, and the stability and the anti-interference capability of the CAN bus network are improved; compared with the prior art, the system provided by the embodiment has the advantages of simple hardware structure, low cost and greatly simplified data processing.

In one embodiment, as shown in fig. 7, an embodiment of the present invention provides a synchronous dual-redundancy CAN bus communication method, including the following steps:

s1, controlling a first CAN controller to send data frames to each CAN transceiver in a CAN transceiver module;

s2, detecting whether the first CAN controller and the first CAN transceiver successfully receive and transmit data frames, and judging whether the node is damaged according to the recorded fault accumulation times and a preset fault threshold value;

and S3, detecting whether at least one of the second CAN transceiver and the third CAN transceiver successfully receives the data frame, and judging whether the other CAN transceiver has the same data frame.

It should be noted that, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by the function and the inherent logic of the process, and should not constitute any limitation to the implementation process of the embodiment of the present application.

For specific limitation of a synchronous dual-redundancy CAN bus communication method, reference may be made to the above limitation on a synchronous dual-redundancy CAN bus communication system, and details are not repeated here. Those of ordinary skill in the art will appreciate that the various modules and steps described in connection with the embodiments disclosed herein may be implemented as hardware, software, or combinations of both. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The embodiment of the invention provides a synchronous dual-redundancy CAN bus communication method, which realizes synchronous receiving and transmitting of dual-redundancy CAN through at least three CAN controllers and CAN transceivers; meanwhile, one CAN controller is used for sending data frames, and the other two CAN transceivers are connected to a CAN bus, so that the output of external redundant lines is realized, and the CAN controller is ensured not to be interfered when sending the data frames; compared with the prior art, the method provided by the embodiment CAN realize the complete decoupling separation of the CAN controller for error detection and the CAN controller for data transmission without increasing additional data transmission, reduce the redundant judgment workload of the receiving node and improve the working efficiency of the system.

FIG. 8 is a computer device including a memory, a processor, and a transceiver connected via a bus according to an embodiment of the present invention; the memory is used to store a set of computer program instructions and data and may transmit the stored data to the processor, which may execute the program instructions stored by the memory to perform the steps of the above-described method.

Wherein the memory may comprise volatile memory or nonvolatile memory, or may comprise both volatile and nonvolatile memory; the processor may be a central processing unit, a microprocessor, an application specific integrated circuit, a programmable logic device, or a combination thereof. By way of example, and not limitation, the programmable logic devices described above may be complex programmable logic devices, field programmable gate arrays, general array logic, or any combination thereof.

In addition, the memory may be a physically separate unit or may be integrated with the processor.

It will be appreciated by those of ordinary skill in the art that the architecture shown in fig. 8 is a block diagram of only a portion of the architecture associated with the present solution and is not intended to limit the computing devices to which the present solution may be applied, and that a particular computing device may include more or less components than those shown, or may combine certain components, or have the same arrangement of components.

In one embodiment, the present invention provides a computer readable storage medium, on which a computer program is stored, which when executed by a processor implements the steps of the above-described method.

The embodiment of the invention provides a synchronous dual-redundancy CAN bus communication system, a method, equipment and a medium, wherein the synchronous dual-redundancy CAN bus communication system transmits TXD of one CAN controller to the other two CAN controller branches on hardware, so that time delay is eliminated, accurate control of a CAN bus is improved, the technical effect that the synchronous dual-redundancy CAN bus is still kept synchronous by local interference is realized, the workload of software processing is simplified, the real-time performance and the safety of the CAN bus system are improved, the purposes of no worry in transmission and ready use in receiving are really achieved, the system provided by the embodiment has a simple structure and strong anti-interference capability of the bus, and has great application value for stable operation of engineering machinery and tramways.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in, or transmitted from one computer-readable storage medium to another computer-readable storage medium, the computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device including one or more available media, such as a magnetic medium (e.g., floppy disks, hard disks, magnetic tapes), an optical medium (e.g., DVDs), or a semiconductor medium (e.g., SSDs), etc.

Those skilled in the art will appreciate that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and the computer program can include the processes of the embodiments of the methods described above when executed.

The above-mentioned embodiments only express some preferred embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these should be construed as the protection scope of the present application. Therefore, the protection scope of the present patent shall be subject to the protection scope of the claims.

Claims

1. A synchronous dual redundant CAN bus communication system, comprising: the system comprises a microprocessor, a CAN transceiver module and a bus system which are connected in sequence;

at least three independent CAN controllers are arranged in the microprocessor, and are respectively a first CAN controller, a second CAN controller and a third CAN controller;

2. A synchronous dual redundant CAN bus communication system as recited in claim 1, wherein: a first terminal resistor is arranged between a CANH pin and a CANL pin of the first CAN transceiver, so that the first CAN controller and the first CAN transceiver form a self-transceiving loop; wherein the first termination resistor is used for impedance matching;

the first termination resistance comprises a 60 Ω termination resistance.

3. A synchronous dual redundant CAN bus communication system as recited in claim 1, wherein: and second terminal resistors are arranged at two ends of a CAN bus in the bus system.

4. A synchronous dual redundant CAN bus communication system as recited in claim 3, wherein: the second termination resistance comprises a 120 Ω termination resistance.

5. A synchronous dual redundant CAN bus communication system as recited in claim 1, wherein: the second CAN transceiver and the third CAN transceiver are used for respectively transmitting the data frames sent by the first CAN controller to the two CAN buses and receiving the data frames transmitted by the two CAN buses.

6. A synchronous dual redundant CAN bus communication system as recited in claim 1, wherein:

the microprocessor is used for detecting whether the first CAN controller and the first CAN transceiver successfully receive and transmit data frames and judging whether the node is damaged or not according to the recorded fault accumulation times and a preset fault threshold;

7. A synchronous dual redundant CAN bus communication system as recited in claim 1, wherein: the number of the CAN controllers is the same as the number of the CAN transceivers in the CAN transceiver module.

8. A synchronous dual-redundant CAN bus communication method applied to the synchronous dual-redundant CAN bus communication system according to any one of claims 1 to 7, the method comprising the steps of:

9. A computer device, characterized by: comprising a processor and a memory, the processor being connected to the memory, the memory being adapted to store a computer program, the processor being adapted to execute the computer program stored in the memory to cause the computer device to perform the method of claim 8.

10. A computer-readable storage medium characterized by: the computer-readable storage medium has stored thereon a computer program which, when executed, implements the method of claim 8.