CN110162008B

CN110162008B - A new energy vehicle CAN bus analysis method

Info

Publication number: CN110162008B
Application number: CN201910389975.0A
Authority: CN
Inventors: 王伟; 郭琳; 王茜; 樊金娜; 曲辅凡; 李海斌; 马欢欢; 曹磊
Original assignee: China Automotive Technology and Research Center Co Ltd; CATARC Automotive Test Center Tianjin Co Ltd
Current assignee: China Automotive Technology and Research Center Co Ltd; CATARC Automotive Test Center Tianjin Co Ltd
Priority date: 2019-05-10
Filing date: 2019-05-10
Publication date: 2021-05-28
Anticipated expiration: 2039-05-10
Also published as: CN110162008A

Abstract

The invention provides a CAN bus analysis method for a new energy vehicle, which is characterized in that a diagnostic instrument and a CAN message acquisition monitoring tool are simultaneously connected to a diagnostic port of the vehicle through a data transmission line divided into two parts. The vehicle diagnostic instrument is connected with the vehicle OBD interface, and the diagnostic instrument sends diagnostic services to the vehicle to acquire the change conditions of a plurality of signals; sending a request service to a diagnosis CAN bus by using a diagnostic instrument and monitoring a response signal after the request; meanwhile, the CAN message acquisition monitoring tool is used for monitoring and recording the communication messages, CAN bus signal analysis CAN be carried out, signals needing analysis are calibrated through comparison, analysis and calculation, the vehicle alignment time is shortened, and the efficiency is improved.

Description

CAN bus analysis method for new energy vehicle

Technical Field

The invention belongs to the technical field of new energy vehicle network communication, and particularly relates to a CAN bus analysis method for a new energy vehicle.

Background

With the reduction of resources and the improvement of awareness of environmental protection, new energy vehicles have become a development trend of the automobile industry, a CAN bus is a bus technology which is most and most commonly applied in a vehicle-mounted network system, so that data communication and resource sharing between a control system and a detection system on an automobile are solved, and the CAN bus is also increasingly used on the new energy vehicles.

Unlike conventional vehicles, there are a large number of ECUs in new energy vehicles, including motor controllers, vehicle controllers, battery management systems, engine controllers, and a large number of vehicle CAN signals. In the benchmarking process of the vehicle, a large number of signals are needed as the premise of analysis of key technologies of the vehicle, so that the accuracy of the CAN bus signals is the important signal input of the benchmarking of the vehicle performance.

Disclosure of Invention

In view of the above, the invention provides a new energy vehicle CAN bus analysis method, wherein a vehicle diagnostic apparatus is connected to a vehicle OBD interface, and the diagnostic apparatus sends a diagnostic service to a vehicle to obtain the change conditions of a plurality of signals; through the assistance of relevant CAN message monitoring software, CAN bus signal analysis CAN be performed, the time for vehicle alignment is shortened, and the efficiency is improved.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a CAN bus analysis method for a new energy vehicle comprises the following steps:

s1, connecting the diagnostic instrument and the CAN message acquisition monitoring tool to the diagnostic port of the vehicle through the data transmission line divided into two parts;

s2, sending a request service message of a signal to be analyzed to the diagnostic port through the diagnostic instrument, and monitoring and recording the change condition of the request signal on a monitoring interface of the diagnostic instrument;

s3, monitoring and recording communication messages between the diagnostic instrument and the diagnostic port, namely a request service message and a diagnostic response message, through the CAN message acquisition monitoring tool, combing the response relation according to the displayed address of each controller, and confirming the request ID and the response ID of each controller;

s4, monitoring and recording the format of the request service message through the CAN message acquisition monitoring tool according to the request ID determined in the previous step;

s5, aiming at the response ID corresponding to the previous request ID, monitoring and recording the format of the diagnosis response message through a CAN message acquisition monitoring tool;

s6, marking the signal to be analyzed in the diagnosis response message corresponding to the response ID in the step 5, and obtaining the offset and coefficient of the signal of the marked vehicle;

s7, converting the calibrated diagnosis response message into a message format which CAN be analyzed by DBC through a CAPL programming module of the CAN message acquisition monitoring tool;

s8, compiling a DBC file by the CAN message collecting and monitoring tool according to the information calibrated in the message obtained in the step 7 and the bus protocol;

s9, real vehicle verification, namely, importing a compiled DBC file into the CAN message acquisition monitoring tool, verifying whether the data acquired by the diagnostic instrument is consistent with the data of the CAN message acquisition monitoring tool, if so, verifying that the signal analysis is successful, and if not, repeating the steps S3-S9.

Further, in step S6, the signal to be analyzed specifically includes a DID flag bit calibration corresponding to the signal and a data bit calibration after the flag bit, and the data calibration is completed by comparing the CAN message data value monitored by the CAN message collection monitoring tool with the actual value displayed by the diagnostic apparatus.

Further, the method for DID flag bit calibration and data bit calibration after the flag bit is as follows: by comparing UDS diagnosis command data in the communication message with a data list of the diagnostic instrument, the corresponding relation is combed by receiving and sending time and values, the communication message DID corresponding to the signal is confirmed, and data bit calibration is carried out.

Further, the method for DID flag bit calibration and data bit calibration after the flag bit is as follows: and after the response ID is confirmed, drawing a curve for the data bit of the diagnosis response message, comparing the drawn curve with a software interface drawing curve of the process diagnostic instrument to determine the data position, and finishing the calibration of the data bit.

Compared with the prior art, the invention has the following advantages:

the invention creates the diagnosis service which is connected with the vehicle OBD interface through the vehicle diagnosis instrument and is sent to the vehicle by the diagnosis instrument, and the change conditions of a plurality of signals can be obtained; sending a request service to a diagnosis CAN bus by using a diagnostic instrument and monitoring a response signal after the request; meanwhile, the CAN message acquisition monitoring tool is used for monitoring and recording the communication messages, CAN bus signal analysis CAN be carried out, signals needing analysis are calibrated through comparison, analysis and calculation, the vehicle alignment time is shortened, and the efficiency is improved.

The invention completes the vehicle signal analysis by diagnosing the CAN bus, utilizes the diagnostic instrument to assist the analysis, the diagnostic instrument generally comprises main signals required by the analysis of the whole vehicle, and CAN monitor the physical signal change without installing a sensor, thereby shortening the analysis period and improving the analysis efficiency.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the invention without limitation. In the drawings:

fig. 1 is a flow chart of the method according to the embodiment of the invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

The invention will be described in detail with reference to the following embodiments with reference to the attached drawings.

The CAN bus analysis method for the new energy vehicle comprises the following steps as shown in fig. 1:

step 1, simultaneously connecting a diagnostic instrument and a CANoe tool (namely an upper computer for installing CANoe software) to a diagnostic port of a vehicle through a data transmission line which is divided into two parts, wherein the data transmission line which is divided into two parts ensures the real-time property, the synchronism and the effectiveness of data;

step 2, sending a request service message of a signal to be analyzed to the diagnosis port through the diagnosis instrument, and monitoring and recording the change condition of the request signal on a monitoring interface of the diagnosis instrument; monitoring a current request response signal on a signal monitoring interface of the upper computer diagnostic instrument; the diagnostic instrument adopted by the embodiment is provided with an interface for displaying and monitoring a curve, and the function can realize the independent request of some specified quantity and pay attention to the removal of other quantity so as to avoid causing excessive interference;

step 3, monitoring and recording communication messages between the diagnostic instrument and the diagnostic port through a CANoe tool, specifically, combing the response relation of each controller according to the request service message sent by the diagnostic instrument and the address of each controller displayed by a diagnostic response message returned by the diagnostic port, and confirming the request ID and the response ID of each controller;

step 4, monitoring and recording the format of the request service message through a CANoe tool according to the request ID determined in the previous step; specifically, the record of the request service message under a certain request state provides a basis for the format judgment of the request service message by observing the continuous frames and the sending time interval during the period;

step 5, aiming at the response ID corresponding to the request ID in the previous step, monitoring and recording the format of the diagnosis response message through a CANoe tool; the specific recording method is as step 4;

step 6, marking the signals to be analyzed in the diagnosis response message corresponding to the response ID in the step 5, and acquiring the offset and the coefficient of the signals of the marked vehicle; specifically, the signals to be analyzed comprise DID zone bit calibration corresponding to the signals and data bit calibration after the zone bits, and the data calibration is completed by comparing CAN message data values monitored by a CAN message acquisition monitoring tool and actual values displayed by a diagnostic instrument;

step 7, converting the calibrated diagnosis response message into a message format which can be analyzed by the DBC through a CAPL programming module of the CANoe tool;

step 8, in the CANoe, according to the information calibrated in the message obtained in the step 7, a DBC file is compiled by combining a bus protocol;

and 9, real vehicle verification, namely, importing a compiled DBC file into the CANoe tool, verifying whether the data collected by the diagnostic instrument is consistent with the graphical interface display of the CANoe tool, if so, confirming that the signal analysis is successful, otherwise, re-confirming the ID and DID zone bit of the signal, and repeating the steps 3-9.

In step 6, there are two methods for DID flag bit calibration and data bit calibration after flag bit, one of which is: by comparing UDS (Unified Diagnostic Services) Diagnostic command data in the communication message with a data list of a Diagnostic instrument, the corresponding relation is combed by receiving and sending time and values, a communication message DID (date identifier) corresponding to the signal is confirmed, and data bit calibration is carried out. The other is as follows: and after the response ID is confirmed, drawing a curve for the data bit of the diagnosis response message, comparing the drawn curve with a software interface drawing curve of the process diagnostic instrument to determine the data position, and finishing the calibration of the data bit.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the invention, so that any modifications, equivalents, improvements and the like, which are within the spirit and principle of the present invention, should be included in the scope of the present invention.

Claims

1. a new energy vehicle CAN bus analysis method, is characterized in that comprising the steps:

S1, connect the diagnostic instrument and the CAN message collection and monitoring tool to the diagnostic port of the vehicle at the same time through a data transmission line that is divided into two;

S2, send the request service message of the required analysis signal to the diagnostic port through the diagnostic instrument, and monitor and record the change of the request signal on the monitoring interface of the diagnostic instrument;

S3, monitor and record the communication messages between the diagnostic instrument and the diagnostic port, that is, request service messages and diagnostic response messages, through the CAN message collection and monitoring tool, sort out the response relationship according to the displayed addresses of each controller, and confirm each The request ID and response ID of the controller;

S4, according to the request ID determined in the previous step, monitor and record the format of the request service message through the CAN message collection monitoring tool;

S5, for the response ID corresponding to the request ID in the previous step, monitor and record the format of the diagnostic response message through the CAN message collection monitoring tool;

S6, demarcate the signal to be parsed in the diagnostic response message corresponding to the response ID in step 5, and obtain the offset and coefficient of the target vehicle signal;

S7, convert the above-mentioned calibrated diagnostic response message into a message format that can be parsed by DBC through the CAPL programming module of the CAN message collection and monitoring tool;

S8, according to step 7, obtain the information demarcated in the message through the CAN message collection monitoring tool and compile the DBC file in conjunction with the bus protocol;

S9, real vehicle verification, import the prepared DBC file into the CAN message acquisition and monitoring tool, and verify whether the data collected by the diagnostic instrument is consistent with the data of the CAN message acquisition and monitoring tool. If they are consistent, confirm that the signal analysis is successful. Then repeat steps S3-S9.

2. a kind of new energy vehicle CAN bus analysis method according to claim 1 is characterized in that: in step S6, the signal to be parsed specifically includes the DID mark bit calibration corresponding to the signal and the data bit calibration after the mark bit, through Comparing the CAN message data value monitored by the CAN message acquisition and monitoring tool with the real value displayed by the diagnostic instrument completes the calibration of the data.

3. a kind of new energy vehicle CAN bus analysis method according to claim 2, is characterized in that: the method for DID mark bit calibration and the data bit calibration after the mark bit is as follows:

By comparing the UDS diagnostic command data in the communication message and the data list of the diagnostic instrument, through the sending and receiving time and value, the corresponding relationship is sorted out, the DID of the communication message corresponding to the signal is confirmed, and the data bit is calibrated.

4. a kind of new energy vehicle CAN bus analysis method according to claim 2, is characterized in that: the method for DID mark bit calibration and the data bit calibration after the mark bit is as follows:

After confirming the response ID, draw a curve for the data bits of the diagnostic response message, and compare the drawn curve with the curve drawn by the software interface of the process diagnostic instrument to determine the data location and complete the calibration of the data bits.