CN107985079A - A kind of vehicle torque control method for meeting functional safety requirement - Google Patents

Abstract

The invention discloses a vehicle torque control method that meets functional safety requirements. The VCU includes a torque processing module, a torque safety monitoring module, a controller monitoring module, and an output comparison judgment module. The torque safety monitoring module includes a safety torque calculation module. , fault information processing module and CAN line transmission module, including: the driver requests torque signal to VCU through pedal operation; VCU collects accelerator pedal opening signal, gear signal, drive shaft speed signal and brake pedal opening signal, Analyze the above signals to obtain the initial torque and corrected torque, and then obtain the torque control value and monitoring torque, and judge in real time whether there is an open circuit failure or short circuit failure and safety mechanism failure, and finally output the actual torque value T2 or the vehicle at the lowest idle speed according to the judgment results torque operation. The invention improves the safety of the torque control of the whole vehicle through torque safety monitoring and torque controller monitoring.

Description

A Vehicle Torque Control Method Compliant with Functional Safety Requirements

technical field

The invention relates to the field of safety control of pure electric vehicles, in particular to a vehicle torque control method that meets functional safety design requirements.

Background technique

With the increasing integration and complexity of automotive electronic appliances worldwide, the safety requirements for the operation of automotive electronic appliances continue to rise. The signal interaction between the various modules of electric vehicles is becoming more and more intensive. In order to ensure the correctness of signal collection, processing and transmission, a vehicle torque control method that meets the functional safety design requirements is adopted to avoid the transmission of VCU unexpected driver torque demand commands. security goals. The vehicle controller analyzes the driver's requested torque information according to the accelerator pedal and brake pedal opening signals. In order to ensure the safety and reliability of the torque information analysis, the signal acquisition of the vehicle controller (VCU) and the safety monitoring of the torque information by the VCU are particularly important. Improving the safety of vehicle torque control has become a necessary and difficult problem.

Contents of the invention

In view of the prior art, in order to ensure the safety and reliability of torque information analysis, the signal acquisition of vehicle controller (VCU) and the safety monitoring of torque information by VCU, the present invention provides a vehicle torque control method that meets functional safety requirements.

In order to solve the above technical problems, the present invention proposes a vehicle torque control method that meets functional safety requirements. The VCU includes a torque processing module, a torque safety monitoring module, a controller monitoring module and an output comparison judgment module. The torque safety monitoring The module includes a safe torque calculation module, a fault information processing module and a CAN line transmission module, and the vehicle torque control method includes the following steps:

Step 1) The driver sends a request torque signal to the VCU through pedal operation;

Step 2) The VCU collects the accelerator pedal opening signal, the gear position signal, the transmission shaft speed signal and the brake pedal opening signal, and obtains the initial torque T0 by analyzing the above signals;

Step 3) VCU collects the shift signal of the driver at this time, and based on the initial torque T0 calculated in step 2), obtains the corrected torque T00 through the torque processing module, T00=λ×T0, λ is the correction coefficient, when the VCU collects When the current vehicle shift information obtained is for an upshift operation, λ is 90%, and when the current vehicle shift information collected by the VCU is for a downshift operation, λ is 110%;

Step 4) The VCU obtains the regenerative braking torque T2 according to the collected regenerative braking information, and the torque control value T1=T00+T2;

Step 5) The safe torque calculation module obtains the monitoring torque T0' according to the accelerator pedal opening signal collected by the VCU, the transmission shaft speed signal and the brake pedal opening signal analysis; if T0'=T0, output B0 to the fault information processing module, If T0'≠T0, output B1 to the fault information processing module;

During the signal acquisition process, the safety torque calculation module judges in real time whether there is an open circuit failure or a short circuit failure. When there is an open circuit failure or short circuit failure, the A1 value is output to the fault information processing module. When there is no open circuit failure or short circuit failure, the A0 value is output to the fault information. processing module;

The CAN line transmission module detects the five security mechanisms of CRC check, frame format detection, response error detection, bit detection and bit stuffing in the CAN line. If any one or more of the above security mechanisms fail during CAN line transmission, Then output C1 to the fault information processing module, otherwise, output C0 to the fault information processing module;

Step 6) The torque safety monitoring module outputs the value of the fault information Error 1 according to the above-mentioned acquisition fault judgment, torque calculation fault judgment and CAN line transmission fault judgment as follows:

Step 7) The controller monitoring module monitors the working state of the processor of the VCU in real time, including ROM check, standard RAM check, RAM check, program flow check and clock check; if there is any one or more checks above If the mechanism fails, then output fault information Error2=1 to the output comparison judgment module, otherwise, output fault information Error2=0 to the output comparison judgment module;

Step 8) The output comparison judgment module finally outputs the actual torque value T2 or the whole vehicle runs at the lowest idle torque according to the torque control value T1, the value of the fault information Error 1 and the value of the fault information Error2:

The limp home mode is a pre-calibrated minimum idle torque of the whole vehicle. After entering the limp home mode, the driver's torque request is the minimum idle torque as the VCU torque output value.

Compared with prior art, the beneficial effect of the present invention is:

The present invention is based on the design requirements of functional safety, and especially considers the torque safety monitoring of the driver's torque request. Through the torque safety monitoring and the torque controller monitoring, the ASIL D safety goal of avoiding the unexpected driver's torque command is realized, and the overall performance is improved. Safety of vehicle torque control.

Description of drawings

Fig. 1 is a block diagram of the vehicle torque control method meeting the functional safety requirements of the present invention;

Fig. 2 is a flow chart of the vehicle torque control that meets the functional safety requirements of the present invention;

Fig. 3 is a flow chart of judging the vehicle torque in the vehicle torque control meeting the functional safety requirements according to the present invention.

Detailed ways

The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the described specific embodiments are only for explaining the present invention, and are not intended to limit the present invention.

As shown in Fig. 1 and Fig. 2, a kind of whole vehicle torque control method that meets functional safety requirements proposed by the present invention, includes torque processing module, torque safety monitoring module, controller monitoring module and output comparison judgment module in VCU, described The torque safety monitoring module includes a safe torque calculation module, a fault information processing module and a CAN line transmission module.

The vehicle torque control method includes the following steps:

Step 1) The driver sends a request torque signal to the VCU through pedal operation;

Step 2) The VCU collects the accelerator pedal opening signal, the gear position signal, the transmission shaft speed signal and the brake pedal opening signal, and analyzes the obtained signals to obtain the initial torque T0; by collecting the accelerator pedal and brake pedal signals, the The analog quantity is converted into a percentage digital quantity signal, and the initial torque T0 is obtained by multiplying the maximum output torque of the driving motor calculated by the current vehicle gear information and the transmission shaft speed information;

Step 3) The VCU collects the driver's shift signal at this time, and based on the initial torque T0 calculated in step 2), obtains the corrected torque T00 through the torque processing module. The VCU collects the current vehicle shift information and considers the normal shift operation. Calculate the corrected torque T00 by multiplying the initial torque T0 obtained in step 2) by the current correction coefficient; T00=λ×T0, where λ is the correction coefficient, and when the current vehicle shift information collected by the VCU is for an upshift operation, λ is 90%, when the current vehicle shift information collected by the VCU is downshift operation, λ is 110%;

Step 4) The VCU obtains the regenerative braking torque T2 according to the collected regenerative braking information, and adds the regenerative braking torque T2 to the corrected torque T00 calculated in step 3) to obtain the torque control value T1 at this time, T1=T00+T2;

Step 5) As shown in Figure 1, Figure 2 and Figure 3, during the signal acquisition process, the safe torque calculation module judges in real time whether there is an open circuit failure or a short circuit failure, and when there is an open circuit failure or a short circuit failure, the A1 value is output to the fault information processing module, when there is no open circuit failure or short circuit failure, output A0 value to the fault information processing module; as shown in Figure 3,

The safety torque calculation module of the VCU analyzes and obtains the monitoring torque T0' according to the same calculation method as in step 2) according to the accelerator pedal opening signal, transmission shaft speed signal and brake pedal opening signal collected by the VCU; if T0'=T0 , to prove that there is no error in the torque calculation process, output B0 to the fault information processing module, if T0'≠T0, prove that there is an error in the torque calculation process, and output B1 to the fault information processing module;

The CAN line transmission module detects the five security mechanisms of CRC check, frame format detection, response error detection, bit detection and bit stuffing in the CAN line. If any one or more of the above security mechanisms fail during CAN line transmission, Then output C1 to the fault information processing module, if there is no error in these five mechanisms, output C0 to the fault information processing module;

Step 6) The torque safety monitoring module outputs the value of the fault information Error 1 according to the above-mentioned acquisition fault judgment, torque calculation fault judgment and CAN line transmission fault judgment as follows:

Step 7) The controller monitoring module monitors the working state of the processor of the VCU in real time, including ROM check, standard RAM check, RAM check, program flow check and clock check; if there is any one or more checks above Mechanism failure zhe3 proves that a fault occurs, then output fault information Error2=1 to the output comparison judgment module, if no fault occurs, output fault information Error2=0 to the output comparison judgment module;

Step 8) The output comparison judgment module finally outputs the actual torque value T2 or the whole vehicle runs at the lowest idle torque according to the torque control value T1, the value of the fault information Error 1 and the value of the fault information Error2:

The limp home mode is a pre-calibrated minimum idle torque of the whole vehicle. After entering the limp home mode, the whole vehicle will not respond to the driver's torque request. For the driver's torque request, the lowest idle torque is used as the VCU torque output value.

To sum up, the present invention is based on the design requirements of functional safety, and especially considers the torque safety monitoring of the driver's torque request, and realizes the ASIL D safety goal of avoiding the unexpected driver's torque command through torque safety monitoring and torque controller monitoring. The safety of vehicle torque control is improved.

Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are only illustrative, rather than restrictive. Under the enlightenment of the present invention, many modifications can be made without departing from the gist of the present invention, and these all belong to the protection of the present invention.

Claims (1)

1. A vehicle torque control method meeting functional safety requirements, characterized in that the VCU includes a torque processing module, a torque safety monitoring module, a controller monitoring module and an output comparison judgment module, and the torque safety monitoring module includes a safety torque Calculation module, fault information processing module and CAN line transmission module, the vehicle torque control method includes the following steps: Step 1) The driver sends a request torque signal to the VCU through pedal operation; Step 2) The VCU collects the accelerator pedal opening signal, the gear position signal, the transmission shaft speed signal and the brake pedal opening signal, and obtains the initial torque T0 by analyzing the above signals; Step 3) VCU collects the shift signal of the driver at this time, and based on the initial torque T0 calculated in step 2), obtains the corrected torque T00 through the torque processing module, T00=λ×T0, λ is the correction coefficient, when the VCU collects When the current vehicle shift information obtained is for an upshift operation, λ is 90%, and when the current vehicle shift information collected by the VCU is for a downshift operation, λ is 110%; Step 4) The VCU obtains the regenerative braking torque T2 according to the collected regenerative braking information, and the torque control value T1=T00+T2; Step 5) The safe torque calculation module obtains the monitoring torque T0' according to the accelerator pedal opening signal collected by the VCU, the transmission shaft speed signal and the brake pedal opening signal analysis; if T0'=T0, output B0 to the fault information processing module, If T0'≠T0, output B1 to the fault information processing module; During the signal acquisition process, the safety torque calculation module judges in real time whether there is an open circuit failure or a short circuit failure. When there is an open circuit failure or short circuit failure, the A1 value is output to the fault information processing module. When there is no open circuit failure or short circuit failure, the A0 value is output to the fault information. processing module; The CAN line transmission module detects the five security mechanisms of CRC check, frame format detection, response error detection, bit detection and bit stuffing in the CAN line. If any one or more of the above security mechanisms fail during CAN line transmission, Then output C1 to the fault information processing module, otherwise, output C0 to the fault information processing module; Step 6) The torque safety monitoring module outputs the value of the fault information Error 1 according to the above-mentioned acquisition fault judgment, torque calculation fault judgment and CAN line transmission fault judgment as follows: Step 7) The controller monitoring module monitors the working state of the processor of the VCU in real time, including ROM check, standard RAM check, RAM check, program flow check and clock check; if there is any one or more checks above If the mechanism fails, then output fault information Error2=1 to the output comparison judgment module, otherwise, output fault information Error2=0 to the output comparison judgment module; Step 8) The output comparison judgment module finally outputs the actual torque value T2 or the whole vehicle runs with the lowest idle torque according to the torque control value T1, the value of the fault information Error 1 and the value of the fault information Error 2: The limp home mode is a pre-calibrated minimum idle torque of the whole vehicle. After entering the limp home mode, the driver's torque request is the minimum idle torque as the VCU torque output value.