New energy automobile speed processing method

Abstract

The invention discloses a new energy automobile speed processing method. The new energy automobile speed processing method specifically comprises the following steps that S1, power-on initialization is conducted; s2, high-voltage read is applied, and a driver drives the vehicle to run; and S3, judging whether a vehicle speed effective flag bit ABSFASpeedVD sent by the ABS is equal to 0 or not, if yes, entering the step S4, and if not, entering the step S5. According to the method, various fault performances of the ABS are comprehensively considered, the vehicle speed effective flag bit sent by the ABS, the ABS communication loss fault, the energy recovery forbidding fault, the ABS fault and the checksum fault of 0 * 36B are recognized, and when any condition is met, the VCU judges that the replacement vehicle speed needs to be used for related function control at the moment, so that the control efficiency is improved. According to the invention, torque control such as creeping and cruise control of the VCU caused by inaccurate speed of the ABS is avoided, the operation risk of the vehicle is prevented, the driving safety of a driver is protected, the accuracy of the pure power endurance test of the whole vehicle is ensured, and a guarantee is provided for announcement declaration and performance development of the whole vehicle.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicles, and in particular to a vehicle speed processing method for new energy vehicles. Background Art

[0002] New energy vehicles need to conduct bench tests on pure electric endurance and power economy to obtain basic data of the whole vehicle, which will be used for performance investigation before the whole vehicle is announced and performance development of the product. When conducting bench tests, rear-wheel drive vehicles generally need to place the rear drive wheels on the rotation test bench, and the driven wheels remain stationary. The ABS will monitor the wheel speed of each tire and calculate the reference speed and slip rate of the whole vehicle. When only the drive wheels are in working condition and the driven wheels are not rotating, the ABS software will think that the wheel speed difference is too large at this time, and report a large wheel speed difference fault, which will in turn affect the prohibition of energy recovery flag ABS_NOEVfflag and the valid vehicle speed flag. After the vehicle control unit (hereinafter referred to as "VCU") determines that the prohibition of energy recovery flag of ABS is in place, it will prohibit the energy recovery function. Energy recovery is the recovery of part of the kinetic energy of the whole vehicle during coasting or braking conditions and stores it in the battery, which has a certain contribution to the pure electric endurance of the whole vehicle. If the energy recovery function is disabled, there will be a certain gap between the test results of the pure electric endurance of the whole vehicle and the actual performance, and performance tests such as the pure electric endurance investigation will be greatly affected. Summary of the invention

[0003] The present invention provides a vehicle speed processing method for new energy vehicles, which avoids the impact of torque control such as creeping and cruise control of VCU caused by inaccurate vehicle speed issued by ABS, prevents vehicle operation risks, protects the driving safety of the driver, and also ensures the accuracy of the pure electric endurance test of the whole vehicle, providing guarantee for the announcement and performance development of the whole vehicle.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: a new energy vehicle speed processing method, which specifically includes the following steps: Step S1, power on initialization; Step S2, high voltage ready, the driver drives the vehicle; Step S3, determining whether the vehicle speed validity flag ABS_FA_Speed_VD issued by the ABS is equal to 0, if so, proceeding to step S4, if not, proceeding to step S5; Step S4, VCU uses alternative vehicle speed; Step S5, determining whether ABS communication has been lost, if so, returning to step S4, if not, proceeding to step S6; Step S6, determining whether the VCU reports an ABS fault flag, if so, returning to step S4, if not, proceeding to step S7; Step S7, determining whether the message containing the vehicle speed signal of the ABS is unreliable, if so, returning to step S4, if not, proceeding to step S8; Step S8, determining whether the ABS has issued an energy recovery prohibition flag position, if yes, proceeding to step S9, if no, repeating this step; Step S9, determining whether the bench test over-control prohibition energy recovery flag BenTstInhibitNOEVFlg-cal is equal to 1, if so, proceeding to step S10, if not, proceeding to step S11; Step S10, VCU keeps energy recovery enabled; Step S11: VCU prohibits energy recovery from being enabled.

[0005] Preferably, in step S4, the VCU uses an alternative vehicle speed, specifically: Step S41, alternative vehicle speed calculation; Step S42, determining whether the vehicle model is a multi-gear configuration, if yes, proceeding to step S43, if no, proceeding to step S44; Step S43, using the transmission output shaft speed as a substitute vehicle speed; Step S44, using the motor output shaft speed to calculate the vehicle speed instead; Step S45, the VCU determines whether the vehicle is in the remote locking control state, if so, proceeds to step S46, if not, repeats this step; Step S46, determining whether the alternative vehicle speed is higher than a threshold value, if yes, repeat this step, if no, proceed to step S47; Step S47, the VCU sends a speed control mode instruction to the MCU, and simultaneously sends the speed limit and the real-time driver required speed; Step S48, determining whether the MCU feedback enters the speed control mode successfully, if yes, proceeding to step S49, if no, proceeding to step S410; Step S49, the MCU enters the speed control mode, and the MCU performs speed PI closed-loop control according to the target speed sent by the VCU; Step S410: Report a failure to enter the speed control mode, and the VCU controls the vehicle driving torque to 0.

[0006] Preferably, the specific content of step S3 is: when the vehicle speed valid flag issued by the ABS is reset, the ABS considers that the vehicle speed calculated by itself is unreliable, which may be caused by sensor failure or controller hardware and software abnormality. After ABS_FA_Speed_VD=0, the VCU considers that the vehicle speed issued by the ABS is unreliable and switches the alternative speed to the vehicle speed.

[0007] Preferably, the specific content of step S4 is: when the VCU determines that the communication with the ABS is abnormal, the VCU determines that the ABS communication is lost at this time, and the vehicle speed signal it sends is also not credible, because the VCU can no longer receive the vehicle speed calculated by the ABS, and the speed signal on the natural bus is not credible. The VCU believes that the vehicle speed sent by the ABS is not credible, and switches the alternative speed to the vehicle speed.

[0008] Preferably, the specific content of step S5 is: when ABS determines that the wheel speeds of the front and rear wheels are abnormal, ABS will prohibit energy recovery to prevent VCU from applying electric braking and causing the whole vehicle to lose control. This problem does not exist during bench testing, but ABS cannot identify this working condition. Therefore, during bench testing, when ABS issues a prohibition on energy recovery, VCU believes that the vehicle speed issued by ABS is unreliable and switches the alternative speed to the vehicle speed.

[0009] Preferably, the specific content of step S6 is: when ABS determines that other faults occur in the anti-lock braking system, it will issue an ABS fault flag, and the VCU will report the ABS fault after receiving it. After the fault flag is set, the VCU believes that the vehicle speed issued by the ABS is unreliable and switches the alternative speed to the vehicle speed.

[0010] Preferably, the specific content of step S7 is: when the VCU determines that the checksum of the message containing the ABS vehicle speed signal is wrong, the VCU considers that the message signal is unreliable, the VCU considers that the vehicle speed sent by the ABS is unreliable, and switches the alternative vehicle speed to the vehicle speed to prevent network attacks from tampering with information and affecting vehicle driving safety.

[0011] Preferably, when the bench test is performed, if the ABS sets the energy recovery prohibition flag due to abnormal front and rear wheel speeds in step 5, the VCU will not prohibit energy recovery at this time, thereby ensuring that energy recovery can be performed normally during the pure electric endurance test. The implementation method is to set a bench test-specific calibration quantity BenTstInhibitNOEVFlg_cal, calibrate the logic override before the bench test, mark BenTstInhibitNOEVFlg_cal as 1, and "ignore" the energy recovery prohibition flag reported by the ABS.

[0012] Preferably, the specific content of step S45 is: when the VCU determines that the whole vehicle is in the remote vehicle locking control state, and the VCU cannot receive the vehicle speed sent by the ABS, or the ABS vehicle speed valid flag received by the VCU is 0, in order to protect the driving safety of the vehicle, the VCU will first calculate the alternative vehicle speed by the aforementioned alternative vehicle speed calculation method determined according to the whole vehicle configuration, and then when it is determined that the alternative vehicle speed is higher than the threshold, the motor lock speed is not enabled first, and when the alternative vehicle speed is lower than the threshold, the VCU immediately sends the motor control mode to the MCU as speed control, and synchronously sends the motor speed control speed limit.

[0013] The beneficial effects of adopting the above technical solution are: 1. The present invention comprehensively considers various fault manifestations of ABS. By identifying the valid vehicle speed flag issued by ABS, ABS communication loss fault, energy recovery prohibition fault, ABS fault and 0x36B checksum fault, when any condition is met, VCU determines that an alternative vehicle speed needs to be used to control related functions, thereby avoiding the impact of inaccurate vehicle speed issued by ABS on VCU's creeping, cruise control and other torque controls, preventing vehicle operation risks, protecting the driver's driving safety, and also ensuring the accuracy of the pure electric endurance test of the whole vehicle, providing a guarantee for the vehicle announcement and performance development. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a flow chart for identifying alternative vehicle speed conditions according to the present invention; Figure 2 This is a flow chart of the alternative vehicle speed calculation and remote control vehicle speed failure processing of the present invention. DETAILED DESCRIPTION

[0015] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0016] like Figure 1 to Figure 2 As shown, the present invention is a vehicle speed processing method for new energy vehicles, which avoids the impact of torque control such as creeping and cruise control of VCU caused by inaccurate vehicle speed issued by ABS, prevents vehicle operation risks, protects the driving safety of the driver, and also ensures the accuracy of the pure electric endurance test of the whole vehicle, providing guarantee for the announcement and performance development of the whole vehicle.

[0017] Specifically, Figure 1 to Figure 2 As shown, the specific steps include: Step S1, power on initialization; Step S2, high voltage ready, the driver drives the vehicle; Step S3, determining whether the vehicle speed validity flag ABS_FA_Speed_VD issued by the ABS is equal to 0, if so, proceeding to step S4, if not, proceeding to step S5; Step S4, VCU uses alternative vehicle speed; Step S5, determining whether ABS communication has been lost, if so, returning to step S4, if not, proceeding to step S6; Step S6, determining whether the VCU reports an ABS fault flag, if so, returning to step S4, if not, proceeding to step S7; Step S7, determining whether the message containing the vehicle speed signal of the ABS is unreliable, if so, returning to step S4, if not, proceeding to step S8; Step S8, determining whether the ABS has issued an energy recovery prohibition flag position, if yes, proceeding to step S9, if no, repeating this step; Step S9, determining whether the bench test over-control prohibition energy recovery flag BenTstInhibitNOEVFlg-cal is equal to 1, if so, proceeding to step S10, if not, proceeding to step S11; Step S10, VCU keeps energy recovery enabled; Step S11: VCU prohibits energy recovery from being enabled.

[0018] The specific content of step S3 is: when the vehicle speed valid flag issued by ABS is reset, ABS considers that the vehicle speed calculated by itself is unreliable, which may be caused by sensor failure or controller hardware and software abnormality. After ABS_FA_Speed_VD=0, VCU considers that the vehicle speed issued by ABS is unreliable and switches the alternative speed to the vehicle speed.

[0019] The specific content of step S4 is: when the VCU determines that the communication with the ABS is abnormal, the VCU determines that the ABS communication is lost at this time, and the vehicle speed signal it sends is also not credible, because the VCU can no longer receive the vehicle speed calculated by the ABS, and the speed signal on the natural bus is not credible. The VCU believes that the vehicle speed sent by the ABS is not credible, and switches the alternative speed to the vehicle speed.

[0020] The specific content of step S5 is: when ABS determines that the wheel speeds of the front and rear wheels are abnormal, ABS will prohibit energy recovery to prevent VCU from applying electric braking and causing the whole vehicle to lose control. This problem does not exist during the bench test, but ABS cannot recognize this working condition. Therefore, during the bench test, when ABS issues a prohibition on energy recovery, VCU believes that the vehicle speed issued by ABS is unreliable and switches the alternative speed to the vehicle speed.

[0021] The specific content of step S6 is: when ABS determines that other faults occur in the anti-lock braking system, it will send out an ABS fault flag. After receiving it, the VCU reports the ABS fault. After the fault flag is set, the VCU believes that the vehicle speed sent by the ABS is unreliable and switches the alternative speed to the vehicle speed.

[0022] The specific content of step S7 is: when the VCU determines that the checksum of the message containing the ABS vehicle speed signal is wrong, the VCU considers that the message signal is unreliable, and the VCU considers that the vehicle speed sent by the ABS is unreliable, and switches the alternative vehicle speed to the vehicle speed to prevent network attacks from tampering with information and affecting vehicle driving safety.

[0023] When conducting bench tests, if the ABS sets the energy recovery prohibition flag due to abnormal front and rear wheel speeds in step 5, the VCU will not prohibit energy recovery at this time, ensuring that energy recovery can be performed normally during the pure electric endurance test. The implementation method is to set the bench test special calibration quantity BenTstInhibitNOEVFlg_cal, calibrate the logic override before conducting the bench test, mark BenTstInhibitNOEVFlg_cal as 1, and "ignore" the energy recovery prohibition flag reported by the ABS.

[0024] In step S4, the VCU uses an alternative vehicle speed, the specific content is: Step S41, alternative vehicle speed calculation; Step S42, determining whether the vehicle model is a multi-gear configuration, if yes, proceeding to step S43, if no, proceeding to step S44; Step S43, using the transmission output shaft speed as a substitute vehicle speed; Step S44, using the motor output shaft speed to calculate the vehicle speed instead; Step S45, the VCU determines whether the vehicle is in the remote locking control state, if so, proceeds to step S46, if not, repeats this step; Step S46, determining whether the alternative vehicle speed is higher than a threshold value, if yes, repeat this step, if no, proceed to step S47; Step S47, the VCU sends a speed control mode instruction to the MCU, and simultaneously sends the speed limit and the real-time driver required speed; Step S48, determining whether the MCU feedback enters the speed control mode successfully, if yes, proceeding to step S49, if no, proceeding to step S410; Step S49, the MCU enters the speed control mode, and the MCU performs speed PI closed-loop control according to the target speed sent by the VCU; Step S410: Report a failure to enter the speed control mode, and the VCU controls the vehicle drive torque to 0. The specific content of step S45 is: when the VCU determines that the vehicle is in the remote vehicle lock control state, and the VCU cannot receive the vehicle speed sent by the ABS, or the ABS vehicle speed valid flag received by the VCU is 0, in order to protect the driving safety of the vehicle, the VCU will first calculate the alternative vehicle speed by the aforementioned alternative vehicle speed calculation method determined according to the vehicle configuration, and then determine that the alternative vehicle speed is higher than the threshold. The motor lock speed is not enabled first. When the alternative vehicle speed is lower than the threshold, the VCU immediately sends the motor control mode to the MCU as speed control, and simultaneously sends the motor speed control speed limit.

[0025] When the MCU receives the speed mode control instruction from the VCU, it will start to respond to the speed request from the VCU. The VCU calculates the motor speed required by the driver based on the alternative vehicle speed and the throttle opening. The VCU sends the driver's required motor speed to the MCU for execution. The MCU controls the speed based on the driver's required speed issued by the VCU and the speed limit issued by the VCU.

[0026] If the MCU cannot enter the speed control mode due to its own software or hardware problems, such as a resolver failure, the VCU will gradually reduce the vehicle's drive torque at a safe speed to control the vehicle, thereby achieving compatibility with safety and controllability.

[0027] After the MCU successfully enters the speed control mode, the MCU enables the speed closed-loop control, compares the driver's required speed issued by the VCU with the motor speed collected by the resolver to obtain the speed difference, and calculates the reference current value in the speed loop PI controller by table lookup. The speed loop reference current value is output to the current inner loop, and the current inner loop obtains the calculated three-phase current by sampling the two resistors through coordinate transformation to obtain the quadrature-axis current and direct-axis current.

[0028] The current inner loop compares the quadrature and direct-axis reference current values ​​output by the speed outer loop with the actual quadrature and direct-axis current values ​​after coordinate transformation to obtain the current difference. Similarly, the quadrature-axis voltage and direct-axis voltage are calculated in the current loop PI controller by table lookup, and then sent to the SVPMW for wave control through inverse PARK transformation.

[0029] The above is an exemplary description of the present invention in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above-mentioned concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for processing vehicle speed of a new energy vehicle, characterized in that: The specific steps include: Step S1, power on initialization; Step S2, high voltage ready, the driver drives the vehicle; Step S3, determining whether the vehicle speed validity flag ABS_FA_Speed_VD issued by the ABS is equal to 0, if so, proceeding to step S4, if not, proceeding to step S5; Step S4, VCU uses alternative vehicle speed; Step S5, determining whether ABS communication has been lost, if so, returning to step S4, if not, proceeding to step S6; Step S6, determining whether the VCU reports an ABS fault flag, if so, returning to step S4, if not, proceeding to step S7; Step S7, determining whether the message containing the vehicle speed signal of the ABS is unreliable, if so, returning to step S4, if not, proceeding to step S8; Step S8, determining whether the ABS has issued an energy recovery prohibition flag position, if yes, proceeding to step S9, if no, repeating this step; Step S9: Determine the bench test over-control prohibition energy recovery flag BenTstInhibitNOEVFlg - Is cal equal to 1? If yes, go to step S10; if no, go to step S11; Step S10, VCU keeps energy recovery enabled; Step S11: VCU prohibits energy recovery from being enabled.

2. A new energy vehicle speed processing method according to claim 1, characterized in that: In step S4, the VCU uses an alternative vehicle speed, the specific content is: Step S41, alternative vehicle speed calculation; Step S42, determining whether the vehicle model is a multi-gear configuration, if yes, proceeding to step S43, if no, proceeding to step S44; Step S43, using the transmission output shaft speed as a substitute vehicle speed; Step S44, using the motor output shaft speed to calculate the vehicle speed instead; Step S45, the VCU determines whether the vehicle is in the remote locking control state, if so, proceeds to step S46, if not, repeats this step; Step S46, determining whether the alternative vehicle speed is higher than a threshold value, if yes, repeat this step, if no, proceed to step S47; Step S47, the VCU sends a speed control mode instruction to the MCU, and simultaneously sends the speed limit and the real-time driver required speed; Step S48, determining whether the MCU feedback enters the speed control mode successfully, if yes, proceeding to step S49, if no, proceeding to step S410; Step S49, the MCU enters the speed control mode, and the MCU performs speed PI closed-loop control according to the target speed sent by the VCU; Step S410: Report a failure to enter the speed control mode, and the VCU controls the vehicle driving torque to 0.

3. A new energy vehicle speed processing method according to claim 1, characterized in that: The specific content of step S3 is: when the vehicle speed valid flag issued by ABS is reset, ABS considers that the vehicle speed calculated by itself is unreliable, which may be caused by sensor failure or controller hardware and software abnormality. After ABS_FA_Speed_VD=0, VCU considers that the vehicle speed issued by ABS is unreliable and switches the alternative speed to the vehicle speed.

4. A new energy vehicle speed processing method according to claim 1, characterized in that: The specific content of step S4 is: when the VCU determines that the communication with the ABS is abnormal, the VCU determines that the ABS communication is lost at this time, and the vehicle speed signal it sends is also not credible, because the VCU can no longer receive the vehicle speed calculated by the ABS, and the speed signal on the natural bus is not credible. The VCU believes that the vehicle speed sent by the ABS is not credible, and switches the alternative speed to the vehicle speed.

5. A new energy vehicle speed processing method according to claim 1, characterized in that: The specific content of step S5 is: when ABS determines that the wheel speeds of the front and rear wheels are abnormal, ABS will prohibit energy recovery to prevent VCU from applying electric braking and causing the whole vehicle to lose control. This problem does not exist during bench testing, but ABS cannot identify this working condition. Therefore, during bench testing, when ABS issues a prohibition on energy recovery, VCU believes that the vehicle speed issued by ABS is unreliable and switches the alternative speed to the vehicle speed.

6. A new energy vehicle speed processing method according to claim 1, characterized in that: The specific content of step S6 is: when ABS determines that other faults occur in the anti-lock braking system, it will send out an ABS fault flag. After receiving it, the VCU reports the ABS fault. After the fault flag is set, the VCU believes that the vehicle speed sent by the ABS is unreliable and switches the alternative speed to the vehicle speed.

7. A new energy vehicle speed processing method according to claim 1, characterized in that: The specific content of step S7 is: when the VCU determines that the checksum of the message containing the ABS vehicle speed signal is wrong, the VCU considers that the message signal is unreliable, and the VCU considers that the vehicle speed sent by the ABS is unreliable, and switches the alternative vehicle speed to the vehicle speed to prevent network attacks from tampering with information and affecting vehicle driving safety.

8. A new energy vehicle speed processing method according to claim 5, characterized in that: When conducting the bench test, if the ABS sets the energy recovery prohibition flag due to abnormal front and rear wheel speeds in step 5, the VCU will not prohibit energy recovery at this time, ensuring that energy recovery can be performed normally during the pure electric endurance test. The implementation method is to set the bench test special calibration quantity BenTstInhibitNOEVFlg_cal, calibrate the logic override before conducting the bench test, mark BenTstInhibitNOEVFlg_cal as 1, and "ignore" the energy recovery prohibition flag reported by the ABS.

9. A new energy vehicle speed processing method according to claim 2, characterized in that: The specific content of step S45 is: when the VCU determines that the vehicle is in the remote vehicle lock control state, and the VCU cannot receive the vehicle speed sent by the ABS, or the ABS vehicle speed valid flag received by the VCU is 0, in order to protect the driving safety of the vehicle, the VCU will first calculate the alternative vehicle speed by the aforementioned alternative vehicle speed calculation method determined according to the vehicle configuration, and then when it is determined that the alternative vehicle speed is higher than the threshold, the motor lock speed is not enabled first. When the alternative vehicle speed is lower than the threshold, the VCU immediately sends the motor control mode to the MCU as speed control, and simultaneously sends the motor speed control speed limit.

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