A system architecture and method for ensuring data communication reliability with dual CAN buses

Abstract

This invention detects the time when the dual-channel CAN bus message is transmitted to the CAN controller node. The CAN controller node uses this time as a redundant timeout judgment mechanism, and the receiver node judges the validity of the received dual-channel CAN bus synchronization message. sex is processed. This method of dual-channel CAN bus synchronous transmission can ensure the reliability of data transmission to the greatest extent. At the same time, due to the existence of the timeout mechanism, the judgment of system failure is very timely. The way of dual synchronous hot redundancy can ensure the normal operation of at least one CAN bus in the event of bus failure or node failure, and does not require a redundant switching process.

Description

technical field [0001] The invention relates to the field of bus data communication, in particular to a system architecture and a method for ensuring the reliability of data communication with dual CAN buses, and is applicable to occasions where CAN bus networks are used to form reliable communication in fields such as ships, buildings, and industrial production. Background technique [0002] CAN is the abbreviation of Controller Area Network. It was developed by German BOSCH company, which is famous for R&D and production of automotive electronic products, and finally became an international standard (ISO11898). It is one of the most widely used field buses in the world. . [0003] CAN bus technology has been widely used in various detection and control systems. CAN bus has many advantages, such as supporting multi-master structure, non-destructive arbitration mechanism based on priority, high transmission rate, etc., which can meet the real-time and reliability requiremen...

AI Technical Summary

Problems solved by technology

However, the CAN bus itself only defines the implementation of the underlying physical layer and data link layer, and does not specify the application layer. The implementation of the application layer still needs to be defined by a high-level protocol, and the requirements for ensuring real-time and reliability of industrial field applications are still insufficient. , there are mainly: 1) CAN bus itself is triggered based on events, and there is uncertainty in the transmission time of data on the bus. At the same time, the priority inversion caused by bus arbitration exacerbates this possibility; 2) CAN bus data link layer encoding The mechanism makes the filling and length of the message uncertain, which affects its internal complex error detection mechanism, and the reliability of data communication cannot meet expectations

[0004] At present, there are many technical solutions to improve the real-time performance and reliability of the CAN bus, and the improvement of real-time performance stays at the theoretical stage. The mechanism of time slice trigger transmission enables any priority task to be executed, but precise clock synchronization is required between CAN nodes, which increases the application cost and design complexity. Since the CAN high-level protocol can be customized by the user , there is still room for improvement in this way to improve real-time performance

The increase in reliability is currently mostly achieved by adding redundancy mechanisms and improving the topology of the CAN bus network. Now commonly used topology networks include bus topology, ring topology, star topology, and mesh topology. These topologies have their own advantages and disadvantages. In practical applications, the bus-type topology structure is widely used because of its simple and reliable network, but this kind of network structure can only detect bus-level errors, and cannot detect node-level faults in time.

[0005] China's application number is 200810106342.6, and the invention patent titled "Dual Redundant CAN Bus Communication System and Its Communication Method" discloses a dual redundant CAN bus communication system and its communication method, which is recorded by a communication registration form. For the fault state of two redundant buses, the judgment of the fault is to send the test frame test through the two buses respectively, so first of all, the data transmission of this patent is asynchronous; the identification of the fault in the proposed patent is again through a single channel (A channel or Road B) is marked by its own timeout. According to the original text, the two redundant lines are switched between the main and secondary channels when their own line timeout overflows; Simultaneous transmission reduces the bandwidth of the single-channel bus, but this two-channel simultaneous transmission is still asynchronous, that is, some messages pass through the A channel, and some messages pass through the B channel. The defect of this method is that it can only guarantee the effective transmission of data. , but the real-time performance of data transmission cannot be guaranteed

Images