CAN bus test system and test method

[0020] First embodiment

[0021] figure 1 It is the main structure block diagram of the CAN bus test system provided by the first embodiment of the present invention. Please refer to figure 1 , CAN bus test system includes: host computer 101, bus monitoring equipment 103, programmable power supply 105, control unit 107.

[0022] The host computer 101 is connected to the program-controlled power supply 105 and the bus monitoring device 103, and is used to send a voltage control command that simulates the voltage waveform output by the battery during the startup of the automobile engine to the program-controlled power supply 105 according to the set voltage waveform.

[0023] Specifically, the upper computer 101 can set the voltage waveform through the CAPL program of the CANoe software platform set in it to simulate the change of the battery supply voltage during the start of the car, so as to automatically control the programmed power supply 105 according to the set voltage waveform The power supply voltage is output, and the upper computer 101 can send a voltage control command to the program-controlled power supply 105 through a GPIB (General-Purpose Interface Bus) protocol. The power supply voltage waveform is correspondingly simplified according to the actual vehicle battery, engine and starter parameters and experience values. The waveform is as figure 2 Shown.

[0024] Further, the host computer can be adjusted for different car models figure 2 (For example, voltage parameter VL0, first time parameter Crank1, second time parameter Crank2, third time parameter Crank3) to simulate and set voltage waveforms, such as image 3 As shown, the upper computer 101 can fill in the parameter setting fields (such as VL0, Crank1, Crank2, Crank3, first voltage parameter, second voltage parameter, third voltage parameter, etc.) in the man-machine interface of the control panel set on it , And then start the test switch StarterEnable on the host computer 101 to the On position, the written CAPL program automatically controls the programmable power supply 105 according to the above voltage waveform, and the set voltage waveform can be provided to the programmable power supply 105 to simulate The voltage waveform output by the battery during the start of the car engine. In addition, because the voltage waveform in the actual starting process of the automobile is extremely irregular, the present invention appropriately simplifies the voltage waveform of the battery during the engine starting process, so that the voltage waveform can be simulated by the upper computer 101. Preferably, the host computer 101 can also initialize the bus monitoring device 103, the program-controlled power supply 105, and the control unit 107. Specifically, the host computer 101 can also send initialization instructions to the bus monitoring device 103, the program-controlled power supply 105, and the control unit 107 to After initialization, the states of the bus monitoring device 103, the programmable power supply 105, and the control unit 107 will all be reset to the default state.

[0025] The programmable power supply 105 is connected to the upper computer 101 and the control unit 107, and is used for outputting a supply voltage to the control unit 107 according to the voltage control instruction sent by the upper computer 101.

[0026] The control unit 107 is connected to the program-controlled power supply 105, and is also connected to the bus monitoring device 103 through the CAN bus 111, and is used to determine whether to send a communication message to the CAN bus 111 for transmission under the power supply voltage output by the program-controlled power supply 105. Among them, the control unit may be an electronic control unit of an automobile.

[0027] In this way, the control unit 107 will perform CAN bus communication under the output power supply voltage. The control unit 107 can be set according to needs, and one or more can be set to meet one or more test requirements at the same time. If the supply voltage is less than a voltage threshold (for example, the first voltage parameter), the control unit 107 does not send a communication message to the CAN bus 111, if it is greater than or equal to the second voltage parameter, the control unit 107 sends a communication message to the CAN bus 111 .

[0028] The bus monitoring device 103 is connected to the control unit 107 through the CAN bus 111, and is also connected to the upper computer 101 for monitoring the transmission of communication messages on the CAN bus 111 and providing the transmission of the communication messages to the upper computer 101. The communication message transmission situation may include, for example, whether there is a communication message, a communication message transmission value, a communication message sending time, a communication message resuming transmission time, and a communication message stop sending time.

[0029] The host computer 101 is also used to compare the transmission condition of the communication message monitored by the bus monitoring device 103 with the pre-stored preset value to determine whether the CAN bus 111 meets the communication requirements during the startup of the car.

[0030] Among them, the host computer 101 can analyze the CAN bus communication behavior of the control unit 107 under the set voltage waveform according to the time when the voltage control instruction is sent to the programmable power supply 105 and the communication message transmission condition monitored by the bus monitoring device 103 The pre-stored setting values ​​are compared to determine whether the CAN bus of the control unit 107 meets the design requirements during the startup of the automobile engine.

[0031] Further, the upper computer 101 is also used to calculate the delay time of the stop sending message according to the communication message stop sending time and the communication message sending time in the communication message transmission situation, and calculate the stop sending message delay time and the pre-determined time. The set values ​​are compared, and it is judged whether the CAN bus meets the communication requirements during the start of the car.

[0032] Further, the upper computer 101 is also used to calculate the resuming transmission message delay time according to the communication message resuming transmission time and the communication message transmission time in the communication message transmission situation, and to calculate the resuming transmission message delay time and the pre-determined transmission time. The set values ​​are compared, and it is judged whether the CAN bus meets the communication requirements during the start of the car.

[0033] Further, the host computer 101 is also used to compare the transmission value of the communication message with the preset value, and determine whether the CAN bus meets the communication requirements during the startup of the car.

[0034] The pre-stored setting value of the host computer 101 may be the setting value of the time when the CAN bus communication message stops sending, the setting value of the time when the communication message resumes transmission, and so on. In practice, if the delay time of stopping sending the message, the delay time of resuming the sending message, and the transmission value of the communication message meet the set value, it can be judged that the CAN bus of the control unit 107 meets the normal communication behavior during the start of the car. Otherwise, it is determined that the normal communication behavior is not satisfied.

[0035] Specifically, according to figure 2 The specific test process can also be: the host computer 101 is also used to set the first preset time period and voltage parameters in the voltage waveform, such as the first voltage parameter VL0, the second voltage parameter V1, and the third voltage parameter V2 .

[0036] When testing like figure 2 When the communication behavior of the CAN bus under the voltage waveform within the time range corresponding to the first time parameter Crank1 is shown, that is, the upper computer 101 is programmed to control according to the first preset time period in the set voltage waveform and the first voltage parameter VL0 The power supply 105 sends a voltage control command and records the communication message sending time t0. The program-controlled power supply 105 is used to output the first power supply voltage to the control unit 107 according to the voltage control instruction sent by the host computer 101 and keep the output of the first power supply voltage for a first preset period of time. The control unit 107 outputs the first power supply voltage in the program-controlled power supply 105 Stop sending communication messages to the CAN bus 111. The bus monitoring device 103 monitors the CAN bus 111 communication message stop sending time t1, and provides the monitored communication message stop sending time t1 to the upper computer 101, and the upper computer 101 according to the communication message stop sending time t1 and the communication message sending time t0 calculates and judges whether the delay time ts=t1-t0 meets the requirements, if it meets the requirements, the upper computer 101 can wait for a preset time (for example, less than the first time parameter Crank1) before sending the next voltage control command For the programmable power supply, for example, a voltage control command can be sent to the programmable power supply 105 according to the second voltage parameter V1 or the third voltage parameter V2.

[0037] The upper computer 101 can set a time threshold in advance. If the stop sending message delay time ts=t1-t0 is within the time threshold, it is judged that the stop sending message delay time ts=t1-t0 meets the requirements, otherwise, It is judged as not meeting the requirements, the above process is tested as figure 2 The communication behavior of the CAN bus under the voltage waveform within the time range corresponding to the first time parameter Crank1 is shown. Such as figure 2 In the waveform shown, the first voltage parameter may be less than 7.6 volts. The second voltage parameter may be greater than or equal to 7.6 volts and less than 12 volts, and the third voltage parameter may be greater than or equal to 12 volts.

[0038] After testing the CAN bus communication behavior under the voltage waveform within the time range corresponding to the first time parameter Crank1, you can test again such as figure 2 The communication behavior of the CAN bus under the voltage waveform within the time range corresponding to the third time parameter Crank3 is shown, that is, the upper computer 101 sends a voltage control command to the programmable power supply 105 according to the second voltage parameter V1 in the set voltage waveform. The programmable power supply 105 is used for outputting the second power supply voltage to the control unit 107 according to the voltage control instruction sent by the host computer 101, and the control unit 107 resumes sending communication messages to the CAN bus 111 for transmission under the second power supply voltage output by the programmable power supply 105. The bus monitoring device 103 monitors the CAN bus 111 communication message recovery transmission time t2 and the communication message transmission value, and provides the monitored communication message recovery transmission time t2 and the communication message transmission value to the upper computer 101, which is based on the communication The message recovery transmission time t2 and the communication message sending time t0 are calculated and judged whether the delay time t2s=t2-t0 meets the requirements, and judges whether the transmitted communication message is correct according to the transmission value of the communication message. If required and correct, the host computer 101 can wait for a preset time and send the next voltage control command to the programmable power supply 105, for example, can send a voltage control command to the programmable power supply 105 according to other voltage parameters.

[0039] The upper computer 101 can set a time threshold in advance. If the delay time t2s=t2-t02 for resuming the transmission of the message is within the time threshold, it is judged that the delay time t2s=t2-t02 for the resuming transmission of the message meets the requirements, otherwise, It is judged as not meeting the requirements. In addition, if you start the test, test as figure 2 When the CAN bus communication behavior is under the voltage waveform within the time range corresponding to the third time parameter shown, the host computer 101 sends a voltage control command to the programmable power supply 105 according to the second voltage parameter V1 in the set voltage waveform. The programmable power supply 105 is used to output a second power supply voltage to the control unit 107 according to the voltage control instruction sent by the host computer 101, and the control unit 107 sends communication messages to the CAN bus 111 for transmission under the second power supply voltage output by the programmable power supply 105. The bus monitoring device 103 monitors the CAN bus 111 communication message transmission value, and provides the monitored communication message transmission value to the upper computer 101. The upper computer 101 judges whether the transmitted communication message is correct according to the communication message transmission value. If it is correct, Then the host computer 101 can wait for a preset time and then send the next voltage control command. For example, it can send a voltage control command to the programmable power supply 105 according to other voltage parameters. The upper computer 101 can preset the normal value of the communication message. If the transmission value of the communication message is within the normal value range, it is judged as correct, otherwise, it is judged as incorrect.

[0040] After testing the CAN bus communication behavior under the voltage waveform within the time range corresponding to the first time parameter Crank1, then test figure 2 The communication behavior of the CAN bus under the third voltage parameter V2 shown (corresponding to figure 2 In the shown time period T), that is, the upper computer 101 sends a voltage control command to the programmable power supply 105 according to the set third voltage parameter V2. The programmable power supply 105 is used to output a third power supply voltage to the control unit 107 according to the voltage control instruction sent by the host computer 101, and the control unit 107 resumes sending communication messages to the CAN bus 111 for transmission under the third power supply voltage output by the programmable power supply 105. The bus monitoring device 103 monitors the CAN bus 111 communication message recovery transmission time t3 and the communication message transmission value, and provides the monitored communication message recovery transmission time t3 and communication message transmission value to the upper computer 101, and the upper computer 101 according to the communication The message recovery transmission time t3 and the communication message sending time t0 are calculated and judged whether the delay time t3s=t3-t0 meets the requirements, and judges whether the transmitted communication message is correct according to the transmission value of the communication message. If required and correct, the upper computer 101 can wait a preset time and then send the next voltage control command to the programmable power supply 105, for example, according to other voltage parameters, such as the first voltage parameter VL0, the second voltage parameter V1 or the third voltage parameter V2 sends a voltage control command to the programmable power supply 105.

[0041] The host computer 101 can set a time threshold in advance. If the delay time t3s=t3-t0 for stopping sending the message is within the time threshold, it is judged that the delay time for resuming the sending of the message meets the requirement, otherwise, it is judged as not. Claim. In addition, if you start the test, test as figure 2 When the communication behavior of the CAN bus under the third voltage parameter V2 is shown, that is, the upper computer 101 sends a voltage control command to the programmable power supply 105 according to the third voltage parameter V2 in the set voltage waveform. The programmable power supply 105 is used to output a third power supply voltage to the control unit 107 according to the voltage control instruction sent by the host computer 101, and the control unit 107 sends a communication message to the CAN bus 111 for transmission under the third power supply voltage output by the programmable power supply 105. The bus monitoring device 103 monitors the CAN bus 111 communication message transmission value, and provides the monitored communication message transmission value to the upper computer 101. The upper computer 101 judges whether the transmitted communication message is correct according to the communication message transmission value. If it is correct, Then the host computer 101 can wait for a preset time and then send the next voltage control command. For example, it can send a voltage control command to the programmable power supply 105 according to other voltage parameters. The upper computer 101 can preset the normal value of the communication message. If the transmission value of the communication message is within the normal value range, it is judged as correct, otherwise, it is judged as incorrect. In other embodiments of the present invention, the foregoing voltage waveform test sequence may be performed in other sequences.

[0042] The present invention uses the upper computer to control the program-controlled power supply, simulates the battery voltage waveform during the start of the car, and monitors the CAN bus communication behavior of the control unit under this voltage waveform through the bus monitoring device, and automatically analyzes the test results through the upper computer to achieve Whether the CAN bus meets the design requirements for evaluation purposes.

[0043] To sum up, the CAN bus test system provided by the embodiment of the present invention compares the communication message transmission condition monitored by the bus monitoring device with the pre-stored preset value through the host computer to determine whether the CAN bus conforms to the vehicle startup process Communication requirements, so as to quickly and accurately automatically perform CAN bus testing during automobile startup, with high accuracy, greatly reducing costs and improving test efficiency, and the host computer of the embodiment of the present invention can simulate the automobile according to the set voltage waveform The voltage control command of the voltage waveform output by the battery during the engine start is sent to the program-controlled power supply. The environment of this simulation process of the host computer is the bench test environment, so the interference of other environmental factors to the system can be excluded. The embodiment of the present invention is For the pre-test of the CAN bus, the test accuracy is high, so it can avoid the high change cost of the late change of the control unit and other software and hardware caused by the low test accuracy in the prior art, which can shorten the development cycle of the whole vehicle.

[0044] The CAN bus test is also carried out according to the waveform segment of the voltage waveform, which makes the test convenient and further improves the test efficiency.

[0045] The following are the method embodiments of the present invention. For details that are not described in detail in the method embodiments, reference may be made to the corresponding device embodiments above.

[0046] Second embodiment

[0047] Figure 4 It is a flowchart of the steps of the CAN bus test method provided by the second embodiment of the present invention. Please refer to Figure 4 The equipment required by the method includes a host computer, a bus monitoring device, a program-controlled power supply, and a control unit. The CAN bus test method of this embodiment includes the following steps 401-409.

[0048] In step 401, the host computer sends a voltage control command that simulates the voltage waveform output by the battery during the startup of the automobile engine to the program-controlled power supply according to the set voltage waveform; wherein, preferably, the host computer also sets a number of voltage parameters by adjusting Determine the voltage waveforms of different car models.

[0049] Step 403: The program-controlled power supply outputs the supply voltage to the control unit according to the voltage control instruction sent by the host computer;

[0050] Step 405: The control unit decides whether to send a communication message to the CAN bus for transmission under the power supply voltage output by the programmable power supply;

[0051] Step 407: The bus monitoring device monitors the communication message transmission status on the CAN bus, and provides the communication message transmission status to the upper computer;

[0052] In step 409, the host computer compares the communication message transmission condition monitored by the bus monitoring device with the pre-stored set value and judges whether the CAN bus meets the communication requirements during the startup of the car.

[0053] Wherein, the communication message transmission situation includes at least one of whether there is a communication message, a communication message transmission value, a communication message sending time, a communication message resuming transmission time, and a communication message stop sending time.

[0054] Preferably, the communication message transmission situation includes the communication message transmission time and the communication message stop sending time, and the CAN bus test method further includes: the host computer also according to the communication message stop transmission time and the communication message in the communication message transmission situation The sending time calculates the delay time of stopping sending the message, and comparing the delay time of stopping sending the message with the preset value, and judging whether the CAN bus meets the communication requirements during the start of the car.

[0055] Preferably, the communication message transmission situation includes the communication message transmission time and the communication message resume transmission time, and the CAN bus test method further includes: the host computer also resumes the transmission time and the communication message according to the communication message in the communication message transmission situation The sending time calculates the delay time of resuming the sending message, and comparing the delay time of resuming sending the message with the preset value, and judging whether the CAN bus meets the communication requirements during the start of the car.

[0056] Preferably, the communication message transmission situation includes the communication message transmission value, the CAN bus test method, and further includes: the host computer is also used to compare the communication message transmission value with the preset value to determine that the CAN bus is in the process of starting the car Whether it meets the communication requirements.

[0057] To sum up, the CAN bus test method provided by the embodiment of the present invention compares the communication message transmission condition monitored by the bus monitoring device with the pre-stored preset value through the upper computer to determine whether the CAN bus conforms to the vehicle startup process Communication requirements, so as to quickly and accurately automatically perform CAN bus testing during automobile startup, with high accuracy, greatly reducing costs and improving test efficiency, and the host computer of the embodiment of the present invention can simulate the automobile according to the set voltage waveform The voltage control command of the voltage waveform output by the battery during the engine start is sent to the program-controlled power supply. The environment of this simulation process of the host computer is the bench test environment, so the interference of other environmental factors to the system can be excluded. The embodiment of the present invention is For the pre-test of the CAN bus, the test accuracy is high, so it can avoid the high change cost of the late change of the control unit and other software and hardware caused by the low test accuracy in the prior art, which can shorten the development cycle of the whole vehicle.

[0058] The third embodiment

[0059] Figure 5 It is a flowchart of the steps of the CAN bus test method provided by the third embodiment of the present invention. Figure 5 Is in Figure 4 Based on the improvement. Figure 5 versus Figure 4 The difference is that Figure 5 Each step is Figure 4 Detailed steps of each step in the. Please refer to Figure 5 The CAN bus test method of the embodiment of the present invention may include the following steps 501-509.

[0060] Step 501: The host computer also sends a voltage control instruction to the programmable power supply according to the first preset time period and the first voltage parameter in the set voltage waveform, and records the communication message sending time;

[0061] Step 503: The program-controlled power supply outputs the first supply voltage to the control unit according to the voltage control instruction sent by the host computer and keeps outputting the first supply voltage for a first preset period of time;

[0062] Step 505: The control unit stops sending communication messages to the CAN bus under the first power supply voltage output by the programmable power supply;

[0063] Step 507: The bus monitoring device monitors the CAN bus communication message stop sending time, and provides the monitored communication message stop sending time to the upper computer;

[0064] Step 509: The upper computer calculates and judges whether the delay time of stopping sending the message meets the requirements according to the communication message stop sending time and the communication message sending time. If it meets the requirements, the upper computer waits for a preset time and sends the next voltage control Command to the programmable power supply.

[0065] Preferably, after step 509, it may further include:

[0066] If the next voltage control command is sent by the upper computer to the programmable power supply according to the second voltage parameter in the set voltage waveform, the programmable power supply outputs the second supply voltage to the control unit according to the voltage control command sent by the upper computer; the control unit is in The second power supply output by the programmable power supply resumes sending communication messages to the CAN bus for transmission. The bus monitoring device monitors the CAN bus communication message recovery transmission time and communication message transmission value, and restores the monitored communication message transmission time and The transmission value of the communication message is provided to the upper computer, and the upper computer calculates and judges whether the delay time of resuming the transmission of the message meets the requirements according to the transmission time of the communication message and the transmission time of the communication message, and judges the transmitted communication message according to the transmission value of the communication message Whether the text is correct or not, if it meets the requirements and is correct, the upper computer waits for a preset time and then sends the next voltage control command to the programmable power supply.

[0067] Preferably, after step 509, it may further include:

[0068] If the next voltage control command is sent by the upper computer to the programmable power supply according to the third voltage parameter in the set voltage waveform, the programmable power supply outputs the third supply voltage to the control unit according to the voltage control command sent by the upper computer; the control unit is in Under the third power supply voltage output by the programmable power supply, the communication message is resumed to send communication messages to the CAN bus for transmission. The bus monitoring device monitors the CAN bus communication message recovery transmission time and communication message transmission value, and restores the monitored communication message transmission time and The communication message transmission value is provided to the upper computer, and the upper computer calculates and judges whether the delay time of the resume transmission message meets the requirements according to the communication message recovery transmission time and the communication message transmission time, and judges the transmitted communication according to the communication message transmission value Whether the message is correct, if it meets the requirements and is correct, the upper computer waits for a preset time and then sends the next voltage control command to the program-controlled power supply.

[0069] In summary, the CAN bus test method provided by the embodiment of the present invention also performs CAN bus test according to the waveform segment of the voltage waveform, thereby making the test convenient and further improving the test efficiency.