A control method and system for a new energy vehicle

Abstract

The present invention relates to a control method and system for a new energy vehicle, belonging to the technical field of new energy vehicle safety control. In the present invention, the motor controller directly obtains the signals of the accelerator pedal and the brake pedal and uses them as reference signals. When the vehicle instruction received by the motor controller conflicts with the driver's intention conveyed by the reference signals, the motor controller adopts a brake priority scheme to ensure that the vehicle is in a safe state. At the same time, when the motor controller responds to the motor drive instruction of the vehicle controller, it compares the torque value in the motor drive instruction with the torque value executed by the motor controller at the previous moment. When the difference is greater than the set threshold, the motor controller executes according to the smaller value between the two, avoiding abnormal acceleration and deceleration of the vehicle caused by abnormal vehicle instruction signals due to vehicle controller failure or CAN network abnormality, and further improving the vehicle safety.

Description

Technical Field

[0001] The present invention relates to a control method and system for a new energy vehicle, belonging to the technical field of new energy vehicle safety control. Background Art

[0002] With the increasing depletion of traditional energy sources such as oil and coal and the continuous aggravation of environmental pollution, new energy vehicles have become an inevitable trend in the development of the automotive industry. The motor system is the core component of a new energy vehicle. Its main function is to control the operation of the drive motor, provide power for the vehicle, and can provide an auxiliary braking function during vehicle braking to recover and utilize the braking energy. It can be said that the working state of the motor system directly affects the power output of the whole vehicle and directly affects the driving safety of new energy vehicles. Currently, the vehicle controller receives the throttle pedal signal, brake pedal signal, and gear signal through a low-voltage harness. The vehicle controller identifies the driver's intention based on the throttle pedal signal, brake pedal signal, and gear signal, and parses the above signals into instructions such as the working mode and target torque for controlling the motor system, and uploads the above instructions to the vehicle CAN bus. The motor controller receives the target working mode, target torque and other instruction signals from the vehicle controller through the vehicle CAN bus, and the motor controller controls the motor to work according to the vehicle instructions. When the throttle pedal signal, brake pedal signal, and gear signal are abnormal, or after the vehicle CAN network is attacked, the instructions sent by the vehicle controller to the motor controller are inconsistent with the driver's driving intention, resulting in safety risks for the whole vehicle.

[0003] Therefore, some people have proposed to directly judge the driver's true intention through the motor controller. For example, the Chinese patent application document with the application publication number CN106274550A discloses a safe driving control method for a pure electric vehicle. The motor controller directly obtains the braking signal and throttle opening signal. When the motor controller receives the driving instruction from the vehicle controller, it controls according to the directly obtained braking signal and throttle opening signal. When the braking switch quantity is valid or the throttle switch quantity is invalid, the motor controller does not respond to the driving instruction sent by the vehicle controller or outputs zero torque to the drive motor after a set time. When the braking switch quantity is invalid and the throttle switch quantity is valid, the motor controller responds to the driving instruction from the vehicle controller. Although the above method can eliminate the situation where the vehicle controller fails and issues incorrect driving instructions, and improve the driving safety of the vehicle. In addition to issuing incorrect driving instructions, the vehicle controller may also cause the torque value of the driving instruction received by the motor controller to be abnormal due to a fault or transmission anomaly. For this situation, the above solution cannot effectively identify and control it, resulting in certain safety hazards for the vehicle. Summary of the Invention

[0004] The object of the present invention is to provide a control method and system for a new energy vehicle, so as to solve the problem that there are potential safety hazards in the vehicle due to the failure of the vehicle controller at present.

[0005] The present invention provides a control method for a new energy vehicle to solve the above technical problems. The control method includes the following steps:

[0006] 1) The motor controller directly obtains the accelerator pedal signal and the brake pedal signal, and the motor controller compares the obtained accelerator pedal signal and brake pedal signal with the control instruction received from the vehicle controller;

[0007] 2) When the control instruction received by the motor controller is a motor drive instruction, and at the same time the obtained brake pedal signal is valid, the motor controller does not respond to the motor drive instruction of the vehicle controller. If the obtained brake pedal signal is invalid at the same time, the motor controller responds to the motor drive instruction of the vehicle controller;

[0008] 3) When the motor controller responds to the motor drive instruction of the vehicle controller, it compares the torque value in the motor drive instruction with the torque value executed by the motor controller at the previous moment. If the difference between the two is greater than the set threshold, the motor controller executes the smaller torque value of the two. Otherwise, it executes the torque value in the motor drive instruction.

[0009] The present invention directly obtains the signals of the accelerator pedal and the brake pedal through the motor controller and uses them as reference signals. When the vehicle instruction received by the motor controller conflicts with the driver's intention conveyed by the reference signals, the motor controller adopts a brake priority scheme to ensure the safety of the whole vehicle; at the same time, when the motor controller responds to the motor drive instruction of the vehicle controller, it compares the torque value in the motor drive instruction with the torque value executed by the motor controller at the previous moment, and when the difference is greater than the set threshold, the motor controller executes according to the smaller value between the two, avoiding abnormal acceleration and deceleration of the vehicle caused by abnormal vehicle instruction signals due to vehicle controller failure or CAN network abnormality, and further improving the vehicle safety.

[0010] Further, when the control instruction received by the motor controller is a power generation instruction, and at the same time the obtained accelerator pedal signal is valid, the motor controller executes the power generation instruction of the vehicle controller until it stops.

[0011] Further, the set threshold in the step 3) includes a first set threshold and a second set threshold, and the first set threshold is greater than the second set threshold. When the difference between the two is greater than the first set threshold, the motor controller executes the smaller torque value of the two and performs a fault count; when the difference between the two is greater than the second set threshold and less than the first set threshold, the motor controller executes the smaller torque value of the two.

[0012] Further, when the fault count reaches the set number of times within the set time, the motor controller will report the fault and give an alarm.

[0013] Further, the fact that the motor controller does not respond to the motor drive instruction of the vehicle controller in step 2) means executing zero torque.

[0014] The present invention also provides a control system for a new energy vehicle, and this control system includes:

[0015] A vehicle controller, which is used to connect the accelerator pedal and the brake pedal, generate corresponding control instructions according to the obtained accelerator pedal signal and brake pedal signal, and send them to the motor controller;

[0016] A motor controller, which is directly connected to the accelerator pedal and the brake pedal to directly obtain the accelerator pedal signal and the brake pedal signal, and compare the obtained accelerator pedal signal and brake pedal signal with the control instruction received from the vehicle controller; when the control instruction received by the motor controller is a motor drive instruction, and at the same time the obtained brake pedal signal is valid, then the motor controller does not respond to the motor drive instruction of the vehicle controller, if the obtained brake pedal signal is invalid at the same time, then the motor controller responds to the motor drive instruction of the vehicle controller;

[0017] When the motor controller responds to the motor drive instruction of the vehicle controller, compare the torque value in the motor drive instruction with the torque value executed by the motor controller at the previous moment. If the difference between the two is greater than the set threshold, the motor controller executes the smaller torque value of the two, otherwise, executes the torque value in the motor drive instruction.

[0018] In the present invention, the motor controller directly obtains the signals of the accelerator pedal and the brake pedal and uses them as reference signals. When the vehicle instruction received by the motor controller conflicts with the driver's intention conveyed by the reference signals, the motor controller adopts a brake priority scheme to ensure the safety of the whole vehicle; at the same time, when the motor controller responds to the motor drive instruction of the vehicle controller, compare the torque value in the motor drive instruction with the torque value executed by the motor controller at the previous moment, and when the difference is greater than the set threshold, make the motor controller execute according to the smaller value between the two, avoiding abnormal acceleration and deceleration of the vehicle caused by abnormal vehicle instruction signals due to vehicle controller failure or CAN network abnormality, and further improving the vehicle safety.

[0019] Further, when the control instruction received by the motor controller is a power generation instruction, and at the same time the obtained accelerator pedal signal is valid, then execute the power generation instruction of the vehicle controller until parking.

[0020] Further, the set threshold includes a first set threshold and a second set threshold, and the first set threshold is greater than the second set threshold. When the difference between the two is greater than the first set threshold, the motor controller executes the smaller torque value of the two and performs a fault count; when the difference between the two is greater than the second set threshold and less than the first set threshold, the motor controller executes the smaller torque value of the two.

[0021] Further, if the fault count reaches the set number of times within the set time, the motor controller will report the fault and give an alarm.

[0022] Further, the motor controller not responding to the motor drive instruction of the vehicle controller means executing zero torque. Description of the Drawings

[0023] Figure 1 is a structural block diagram of the control system of the new energy vehicle of the present invention;

[0024] Figure 2 is a flowchart of the control method of the new energy vehicle of the present invention. Detailed Embodiments

[0025] The following further describes the detailed embodiments of the present invention with reference to the drawings.

[0026] System Embodiment

[0027] After receiving the torque instruction sent by the vehicle controller, the motor controller in the present invention compares the torque with the execution torque output by the motor controller at the previous moment. If the difference between the two is greater than the set threshold, the motor controller selects the smaller torque of the two as the current torque, thereby realizing the abnormal protection of the target torque gradient.

[0028] Specifically, as Figure 1 shown, the control system of the new energy vehicle of the present invention includes a motor controller and a vehicle controller. The motor controller and the vehicle controller are connected through a CAN bus, and both the motor controller and the vehicle controller are connected to the accelerator pedal and the brake pedal. The vehicle controller identifies the driver's intention according to the accelerator pedal and brake pedal signals, generates corresponding control instructions and sends them to the motor controller, and the motor controller controls the corresponding actuators to act; at the same time, the motor controller directly obtains the corresponding accelerator pedal signal and brake pedal signal from the accelerator pedal and the brake pedal, and compares the control instruction received from the vehicle controller with the directly obtained accelerator pedal signal and brake pedal signal. The motor controller controls the motor according to the comparison result. When the vehicle instruction received by the motor controller conflicts with the driver's intention, the motor controller adopts a brake priority scheme to ensure the safety of the vehicle.

[0029] The specific control logic adopted by the motor controller is as follows: When the control instruction received by the motor controller is a driving instruction, the motor controller determines whether the directly obtained accelerator pedal signal and brake pedal signal are valid. When the motor controller detects that the brake pedal signal is valid, the motor controller does not respond to the driving instruction of the vehicle controller and executes zero torque; when the motor controller detects that the brake pedal signal is invalid, the motor controller responds to the driving instruction of the vehicle controller; when the control instruction received by the motor controller is a power generation instruction, and at the same time the motor controller detects that the accelerator pedal signal is valid (normally, the accelerator pedal signal should be invalid when receiving a power generation instruction), the motor controller executes the power generation instruction of the vehicle controller until it stops.

[0030] When the motor controller responds to the driving instruction of the vehicle controller, it is necessary to judge the torque signal sent by the vehicle controller. The judgment process is as Figure 2 shown. When the difference between the torque N2 sent by the vehicle controller and the torque N1 executed by the motor controller in the previous frame (previous moment) is greater than N0, where N0 is the first set threshold, the motor controller responds according to the smaller value between the two, and the fault count is incremented by 1; if the difference between the torque N2 sent by the vehicle controller and the torque N1 executed by the motor controller in the previous frame (previous moment) is less than N3, where N3 is the second set threshold, it is executed according to the vehicle target torque; if the difference between the torque N2 sent by the vehicle controller and the torque N1 executed by the motor controller in the previous frame (previous moment) is greater than N3 and less than N0, the motor controller is executed according to the smaller value between the two. If the number of times A that the difference between the torque N2 received by the vehicle controller and the torque N1 instruction executed in the previous frame (previous moment) within the T1 time is greater than the set number A1, a fault is reported, and the motor controller responds according to the smaller value between the torque received by the vehicle controller and the torque instruction executed in the previous frame. If the difference between the target torque of the motor controller and the torque executed in the previous moment is less than a certain threshold for a continuous period of time, the fault is recovered and the vehicle instruction is normally executed. The first set threshold N0 and the second set threshold N3 are determined according to the theoretical maximum difference between the previous frame and the next frame of the normal vehicle instruction.

[0031] Method embodiment

[0032] The control method of the present invention is applicable to new energy vehicles. The motor controller is directly connected to the accelerator pedal and the brake pedal, and directly obtains the accelerator pedal signal and the brake pedal signal. The motor controller compares the obtained accelerator pedal signal and brake pedal signal with the control instructions received from the vehicle controller. When the control instruction received by the motor controller is a motor drive instruction, and at the same time the obtained brake pedal signal is valid, the motor controller does not respond to the motor drive instruction of the vehicle controller. If the obtained brake pedal signal is invalid at the same time, the motor controller responds to the motor drive instruction of the vehicle controller. When the motor controller responds to the motor drive instruction of the vehicle controller, it compares the torque value in the motor drive instruction with the torque value executed by the motor controller at the previous moment. If the difference between the two is greater than the set threshold, the motor controller executes the smaller torque value of the two. Otherwise, it executes the torque value in the motor drive instruction. The specific implementation process has been described in detail in the system embodiment and will not be elaborated here.

[0033] When the vehicle instruction received by the motor controller of the present invention conflicts with the driver's intention conveyed by the reference signal, the motor controller adopts a brake priority scheme to ensure the safety of the vehicle. At the same time, when the motor controller responds to the motor drive instruction of the vehicle controller, it avoids abnormal acceleration and deceleration of the vehicle caused by abnormal vehicle instruction signals due to vehicle controller failures or abnormal CAN networks, further improving vehicle safety.

Claims

1. A control method for a new energy vehicle, characterized in that, The control method includes the following steps: 1) The motor controller directly obtains the throttle pedal signal and the brake pedal signal, and compares the obtained throttle pedal signal and brake pedal signal with the control instructions received from the vehicle controller; 2) When the control instruction received by the motor controller is a motor drive instruction, and at the same time the obtained brake pedal signal is valid, the motor controller does not respond to the motor drive instruction of the vehicle controller. If the obtained brake pedal signal is invalid at the same time, the motor controller responds to the motor drive instruction of the vehicle controller; 3) When the motor controller responds to the motor drive instruction of the vehicle controller, it compares the torque value in the motor drive instruction with the torque value executed by the motor controller at the previous moment. If the difference between the two is greater than the set threshold, the motor controller executes the smaller torque value of the two. Otherwise, it executes the torque value in the motor drive instruction.

2. The control method of the new energy vehicle according to claim 1, characterized in that When the control instruction received by the motor controller is a power generation instruction, and at the same time the obtained throttle pedal signal is valid, the motor controller executes the power generation instruction of the vehicle controller until it stops.

3. The control method of the new energy vehicle according to claim 1 or 2, characterized in that, The set threshold in step 3) includes a first set threshold and a second set threshold, and the first set threshold is greater than the second set threshold. When the difference between the two is greater than the first set threshold, the motor controller executes the smaller torque value of the two and performs a fault count; when the difference between the two is greater than the second set threshold and less than the first set threshold, the motor controller executes the smaller torque value of the two.

4. The control method for a new energy vehicle according to claim 3, characterized in that If the fault count reaches the set number of times within the set time, the motor controller will report the fault and give an alarm.

5. The control method of the new energy vehicle according to claim 1 or 2, characterized in that In step 2), the motor controller not responding to the motor drive instruction of the vehicle controller means executing zero torque.

6. A control system for a new energy vehicle, characterized in that, The control system includes: A vehicle controller, used to connect the throttle pedal and the brake pedal, generate corresponding control instructions according to the obtained throttle pedal signal and brake pedal signal, and send them to the motor controller; A motor controller, used to be directly connected to the throttle pedal and the brake pedal, directly obtain the throttle pedal signal and the brake pedal signal, and compare the obtained throttle pedal signal and brake pedal signal with the control instructions received from the vehicle controller; when the control instruction received by the motor controller is a motor drive instruction, and at the same time the obtained brake pedal signal is valid, the motor controller does not respond to the motor drive instruction of the vehicle controller. If the obtained brake pedal signal is invalid at the same time, the motor controller responds to the motor drive instruction of the vehicle controller; When the motor controller responds to the motor drive instruction of the vehicle controller, it compares the torque value in the motor drive instruction with the torque value executed by the motor controller at the previous moment. If the difference between the two is greater than the set threshold, the motor controller executes the smaller torque value of the two. Otherwise, it executes the torque value in the motor drive instruction.

7. The control system of the new energy vehicle according to claim 6, characterized in that, When the control instruction received by the motor controller is a power generation instruction, and at the same time the obtained throttle pedal signal is valid, it executes the power generation instruction of the vehicle controller until it stops.

8. The control system of the new energy vehicle according to claim 6 or 7, characterized in that, The set thresholds include a first set threshold and a second set threshold, and the first set threshold is greater than the second set threshold. When the difference between the two is greater than the first set threshold, the motor controller executes the smaller torque value of the two and performs a fault count; when the difference between the two is greater than the second set threshold and less than the first set threshold, the motor controller executes the smaller torque value of the two.

9. The control system of the new energy vehicle according to claim 8, characterized in that, If the fault count reaches the set number of times within the set time, the motor controller will report the fault and give an alarm.

10. The control system of the new energy vehicle according to claim 6 or 7, characterized in that, That the motor controller does not respond to the motor drive instruction of the vehicle controller means executing zero torque.

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