A method for analyzing and troubleshooting transient error frames of CAN bus of electric vehicles

Abstract

The present invention discloses a method for analyzing and troubleshooting transient error frames of a CAN bus of an electric vehicle, characterized in that the method comprises the following steps: S1, when a transient error frame of the CAN bus occurs when the ignition lock is switched from ACC to ON, whether there is still an error frame after ON is stable; S2, if there is no error frame after ON is stable, whether there is a high-voltage system in operation; S3, when ensuring that the high-voltage system is not in operation, the node that sends a message in the ACC gear of the ignition lock should be confirmed; S4, the ignition lock is switched to observe whether there is an error frame; S5, the nodes working in the ON gear are connected one by one, the node that introduces the error frame is judged, and the cause of the problem of the node is analyzed. The present invention can quickly and efficiently analyze and locate the source of the transient error frame of the CAN bus by quickly detecting and eliminating various possible influencing factors when the ignition transient error frame occurs, and then orderly introducing nodes and locating the problem nodes, thereby reducing the failure rate of electric vehicles and improving system reliability.

Description

Technical Field

[0001] The invention relates to the technical field of automobile networks, and in particular to a method for analyzing and troubleshooting transient error frames of a CAN bus of an electric vehicle. Background Art

[0002] The vehicle CAN bus error frame problem has always been a difficult problem in CAN communication. There are currently multiple methods for eliminating steady-state error frames, but there is no technical solution for transient error frame troubleshooting. The basic method for steady-state error frames is briefly described as follows:

[0003] When an error frame appears on the vehicle's CAN bus, first check whether the CAN bus terminal resistance is normal; check whether the error frame still appears when the vehicle key is in the power-off state to narrow the scope of investigation; observe whether the vehicle reports a fault when an error frame appears on the CAN bus to narrow the scope of investigation; through the elimination method, gradually remove the electronic control units on the CAN bus, record the data, and observe whether there are error frames until the source of the error frame is locked.

[0004] The existing electric vehicle error frame troubleshooting method technology is only applicable to steady-state error frames, that is, error frames that are stable on different CAN network segments when the ignition lock is turned to the ON position and the vehicle is in the start position. The problem of bus steady-state error frames can be located according to the existing patented error frame troubleshooting method that has been disclosed.

[0005] With the development of the new energy vehicle industry, the electrification, intelligence, networking and sharing of automobiles, the nodes in the vehicle CAN network have become extremely complex. At the same time, for electric vehicles, with the introduction of high voltage, the electromagnetic environment of the vehicle has become extremely harsh, the interference factors of each controller will increase, and the frequency of error frames in different scenarios will also increase, especially transient scenarios. Taking Dongfeng Commercial Vehicles as an example, electric vehicles generally have hundreds of error frames per second when the ignition lock switches from ACC to ON. After the ON gear is stable, there are no error frames in the power CAN and body CAN. For this type of transient error frame problem, the existing error frame troubleshooting method cannot effectively locate the cause of the problem. Summary of the invention

[0006] In view of the problems existing in the background technology, the purpose of the present invention is to provide a method for analyzing and troubleshooting transient error frames of the CAN bus of an electric vehicle, which can quickly lock, shorten the troubleshooting cycle, and improve the stability of the entire vehicle.

[0007] To achieve the above object, the present invention provides a method for analyzing and troubleshooting transient error frames of an electric vehicle CAN bus, which is characterized by comprising the following steps:

[0008] S1, when the ignition lock is switched from ACC to ON, a transient error frame of the CAN bus appears. Check whether there is any error frame after the ON is stable.

[0009] S2, after ON is stable and there is no error frame, it detects whether the high voltage system is working;

[0010] S3, when ensuring that the high voltage system is not working, confirm the node for sending the message in the ignition lock ACC position;

[0011] S4, switch the ignition lock and observe whether there is an error frame;

[0012] S5, connect the nodes working in the ON position one by one, determine the node that introduces the error frame, and analyze the cause of the problem of the node.

[0013] Preferably, in step S4, the bus only retains the ACC gear working node, performs ignition lock switching, and observes whether there is an error frame.

[0014] Preferably, in step S5, first confirm that the bus is normal, then introduce the nodes working in the ON gear one by one, and determine the node that introduces the error frame.

[0015] As a preferred solution, the analysis and investigation method further comprises the following steps:

[0016] S6, after all ON-speed nodes are connected, there are still error frames, check whether there is interference between the ON-speed power supply and the bus;

[0017] S7, measure the ON voltage and analyze the cause of the voltage abnormality.

[0018] Preferably, in step S6, the CAN connection lines of the controller for ACC operation and the controller for ON gear operation are directly connected to observe whether there is a bus error frame when the ignition lock is switched.

[0019] Further preferably, the detection and observation are both performed using a CAN bus analysis instrument.

[0020] Preferably, the analysis and troubleshooting method is used for locating faults in a CAN communication network of an electric vehicle.

[0021] The beneficial effects of the present invention are:

[0022] Compared with the prior art, the present invention can quickly and efficiently analyze and locate the source of the CAN bus transient error frame by quickly detecting and eliminating various possible influencing factors when the ignition transient error frame occurs, and then orderly introduces nodes and locates the problem nodes, thereby reducing the failure rate of electric vehicles and improving system reliability.

[0023] 1. It provides a complete set of CAN transient error frame rapid positioning solutions, which greatly improves the troubleshooting efficiency. Users do not need to conduct a large number of disordered tests to locate the problem, shortens the vehicle downtime caused by the inability to locate the error frame, and reduces the maintenance cost.

[0024] 2. The source of the error frame can be quickly located by removing nodes in an orderly manner. There is no need to check each node one by one, which greatly reduces the positioning time. Generally, the positioning can be completed within 1 hour.

[0025] 3. Detect and remove various external interference factors to avoid interference with judgment and ensure the accuracy of analysis results.

[0026] 4. This solution is suitable for locating transient error frame problems in CAN of most electric vehicles and has strong applicability.

[0027] 5. The solution is simple and clear to operate, and can be used as a standard process for CAN communication troubleshooting, making it easy for engineering and technical personnel to master and use.

[0028] 6. The application of the present invention can greatly improve the stability and reliability of the CAN communication network of electric vehicles, reduce the number of maintenance times, and reduce the cost of use.

[0029] 7. The solution of the present invention enhances the anti-interference capability of the CAN communication network of electric vehicles, improves the ability of electric vehicles to adapt to harsh environments, and expands the range of environmental applications of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a topological diagram of the CAN bus network of the present invention;

[0031] Figure 2 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention (including the preferred technical solution) is further described in detail below by means of the accompanying drawings and by listing some optional embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Embodiment 1

[0034] In this embodiment, CANoe bus analysis tools and Picoscope oscilloscope are used to monitor CAN communication and detect voltage waveforms. The CAN bus network topology is as follows: Figure 1 shown.

[0035] When a transient error frame of the CAN bus occurs when the ignition lock switches from ACC to ON, first check whether there is any error frame after the ON is stable.

[0036] If there is no error frame after the ON is stable, use CANoe to detect whether the high-voltage system is working. Make sure that the high-voltage system is not working after it is completely disconnected.

[0037] Use CANoe to record which nodes send messages on the CAN bus in the ACC mode. Only keep the nodes working in the ACC mode on the CAN bus.

[0038] Then switch the ignition lock and use CANoe to observe whether there are error frames on the bus.

[0039] If no error frame appears, connect the nodes that were originally working in the ON position one by one, and perform an ignition lock switching test each time a node is connected. Until an error frame appears after a node is connected, it can be determined that the node just connected is the problem node that introduced the error frame.

[0040] Check the problem node item by item, mainly analyzing the signal sampling position, baud rate setting, message sending cycle, etc. to determine the cause of the problem.

[0041] If error frames still occur after all ON-mode nodes are connected, further inspection is required to check whether there is interference with the ON-mode power supply and whether the CAN bus is subject to external electromagnetic interference.

[0042] Use Picoscope to detect the voltage waveform of the ON-mode power supply to determine whether there is severe ripple or transient pulse interference.

[0043] Use a multimeter to measure the resistance on the CAN bus to ensure that the impedance between CAN high and CAN low is within the normal range. Also check whether the terminal resistance is normal.

[0044] Embodiment 2

[0045] On the basis of Example 1, the following steps are added:

[0046] When only the ACC gear node is on the bus, perform the ignition lock switching test until the error frame disappears after a certain node is removed. Then it can be determined that the node is the problem node that introduces the error frame.

[0047] After confirming that only ACC working nodes are retained on the bus and there are no error frames, connect the ON nodes one by one, and perform an ignition lock switching test each time one is connected. When an error frame is introduced after a node is connected, it can be determined that the node is a problem node.

[0048] By removing and introducing nodes one by one in this way, the node that introduces the transient error frame can be further verified and accurately located.

[0049] Embodiment 3

[0050] In this embodiment, a CANoe bus analysis tool and a Picoscope oscilloscope are used to view CAN messages and monitor whether error frames appear on the CAN network and the specific messages of the error frames through related software, observe the CAN waveform and voltage waveform, and use a multimeter to measure the resistance between CAN high and CAN low on the CAN bus.

[0051] like Figure 1 As shown in FIG. 1 , the related electronic control units on the CAN bus are listed. The method for checking transient error frames of the electric vehicle CAN bus of this embodiment is as follows: Figure 1 Based on the CAN bus network topology, it includes the following steps:

[0052] A. When the CAN bus error frame appears when the vehicle ignition lock is switched from ACC to ON, first continue to check whether there are still error frames in the vehicle after the ON position is stable.

[0053] B. Check whether the high voltage is working when the ignition lock is switched to narrow the scope of investigation;

[0054] C. When the vehicle is in the ON position without bus error frames and the high voltage system is not working, the controller that sends the message in the ignition lock ACC position should be confirmed;

[0055] D. Only the controller that sends messages in the ignition lock is retained on the bus, and the controllers working in the ON position are connected separately. When the ignition lock is switched, observe whether the bus has an error frame.

[0056] E. When error frames appear when all ON gear controllers are connected separately, it is necessary to check whether the ON gear power supply is normal or whether the CAN bus introduces interference.

[0057] The specific process is as follows Figure 2 As shown:

[0058] SA, when the ignition lock switches and the vehicle CAN bus has transient error frames, you should first continue to check whether there are error frames in the ignition lock ON position. If there are no error frames in the ON position, perform SB steps. If there are stable error frames in the ON position, you can refer to the existing publicly published error frame elimination method to locate the cause, which will not be repeated here.

[0059] SB. Check whether the high-voltage system of the vehicle is working. If not, perform step SC: If the high-voltage system is indeed working, make sure that the high-voltage system MSD is cut off, the BMS and all-in-one controller wiring harness interface are disconnected, and the influence of high voltage is completely eliminated.

[0060] SC, confirm the controller that sends messages in the ACC position of the ignition lock, and then keep only the controller that sends messages in the ACC position on the bus, operate the ignition lock from the ACC position to the ON position, and observe whether there is an error frame. If there is an error frame, the problem controller can be locked by the elimination method of plugging and unplugging the relevant controller that sends messages in the ACC position. If there is no error frame, perform the SD step.

[0061] SD, first ensure that only the controller that sends messages in the ACC position is retained on the bus, then connect the controllers working in the ON position separately, operate the ignition lock from the ACC position to the ON position, and observe whether there is an error frame. If only one controller has an error frame after connection, then the controller can be locked as the problem controller, and the reason why the controller generates an error frame can be analyzed from the software and hardware. If any controller generates an error frame after connection, perform the SE step.

[0062] SE. Use relevant tools to analyze whether abnormal voltage occurs during the process of ON gear voltage rising from 0V to 24V when ACC is switched to ON gear. If abnormal voltage occurs, check the power supply principle of ON gear and related components to identify the real cause.

[0063] The present invention is designed to analyze and troubleshoot the transient error frame of the electric vehicle CAN bus. When the ignition lock is switched from the ACC gear to the ON gear, a transient error frame appears on the CAN bus of the entire vehicle. First, it is necessary to continue to detect whether the bus still has error frames after the ON gear is stable; when there are no error frames on the bus after the ON gear is stable, it is necessary to detect whether there is a high-voltage system working when the ignition lock is switched; when there are no error frames in the ON gear and it is ensured that the high-voltage system is not working, the controller that sends the message in the ACC gear of the ignition lock should be confirmed, and then only the controller that sends the message in the ACC gear of the ignition lock should be retained on the bus; the ignition lock switching action is continued, and whether there is an error frame is observed through a bus analysis tool; if normal, the controllers working in the ON gear are connected separately, and if there is a controller connected to the ignition lock, the controller is disconnected after the ignition lock is turned on. If an error frame appears on the bus during switching, the connected controller can be identified as the problematic controller, and the controller needs to be analyzed separately, mainly from the aspects of sampling point, baud rate, message cycle, etc.; when error frames appear when all ON gear controllers are connected separately, it is necessary to check whether the ON gear power supply is normal or whether the CAN bus introduces interference; directly connect the CAN connection lines of the controller working with ACC and the controller working with ON gear, and observe whether there is a bus error frame when the ignition lock is switched; if it is confirmed that the bus does not introduce interference, use a special tool to measure whether the ON gear voltage is normal, mainly use special tools to observe whether there is abnormal voltage in the ON gear; if the ON gear voltage problem is confirmed, it is necessary to check the ON gear power supply principle and related components to identify the true cause.

[0064] Those skilled in the art will readily appreciate that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, replacements, improvements, etc. made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A method for analyzing and troubleshooting transient error frames of an electric vehicle CAN bus, characterized in that: The following steps are involved: S1, when the ignition lock is switched from ACC to ON, a transient error frame of the CAN bus appears. Check whether there is any error frame after the ON is stable. S2, if there is no error frame after ON is stable, check whether the high voltage system is working and make sure that the high voltage system is not working; S3, while ensuring that the high-voltage system is not working, confirm the node that sends the message in the ACC position of the ignition lock, and keep only the node that sends the message in the ACC position on the bus; S4, switch the ignition lock from ACC to ON, and observe whether the node sending the message in the ACC file reserved by the bus has an error frame; S5, if there is no error frame in step S4, then connect to the nodes working in the ON gear one by one, and perform an ignition lock switching operation for each node connected until an error frame is detected, lock the node that introduces the error frame, and analyze the cause of the problem of the node; S6, after all nodes working in the ON gear are connected, there are still error frames, and it is detected whether there is interference between the ON gear power supply and the bus; S7, measure the ON voltage and analyze the cause of the voltage abnormality.

2. The method for analyzing and troubleshooting transient error frames of an electric vehicle CAN bus according to claim 1 is characterized in that: In step S6, the CAN connection lines of the controller working with ACC and the controller working with ON gear are directly connected to observe whether there is a bus error frame when the ignition lock is switched.

3. The method for analyzing and troubleshooting transient error frames of an electric vehicle CAN bus according to claim 1 is characterized in that: The detection and observation are all completed using a CAN bus analysis instrument.

4. The method for analyzing and troubleshooting transient error frames of a CAN bus of an electric vehicle according to any one of claims 1 to 3, characterized in that: The analysis and troubleshooting method is used for locating faults in a CAN communication network of an electric vehicle.

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