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CN-118219858-B - Vehicle and braking method and device thereof

CN118219858BCN 118219858 BCN118219858 BCN 118219858BCN-118219858-B

Abstract

The invention discloses a vehicle and a braking method and a braking device thereof, wherein the vehicle comprises a braking unit and a motor control unit, and the method comprises the steps that under the condition that the feedback braking function of the motor control unit is normal, if the motor control unit cannot judge whether the braking function of the braking unit is invalid, the motor control unit acquires the state of a brake lamp switch; and if the state of the brake lamp switch is determined to be an on state, controlling braking by the motor control unit based on feedback torque. Therefore, under the condition that whether the braking unit fails or not cannot be judged, the risk of accidents of passengers in the riding process is reduced, and the reliability of vehicle braking is improved.

Inventors

  • CHEN WEIWEI

Assignees

  • 比亚迪股份有限公司

Dates

Publication Date
20260505
Application Date
20231110

Claims (10)

  1. 1. A vehicle braking method, characterized by being applied to a vehicle including a braking unit, a motor control unit, and a brake light switch, the method comprising: Under the condition that the feedback braking function of the motor control unit is normal, if the motor control unit cannot judge whether the braking function of the braking unit is invalid, acquiring the state of the brake lamp switch; if the state of the brake lamp switch is determined to be an on state, feedback torque control braking is performed by the motor control unit based on the vehicle speed; If the motor control unit does not receive the message sent by the braking unit within the first duration or the message sent by the braking unit is abnormal, determining whether the braking unit fails or not; The motor control unit detects whether the feedback braking function of the motor control unit is normal or not; If yes, a first effective prompt message is sent to the braking unit, wherein the first effective prompt message is used for indicating that the feedback braking function of the motor control unit is normal; if not, the motor control unit sends first failure prompt information to the braking unit, wherein the first failure prompt information is used for prompting that the feedback braking function of the motor control unit fails; the motor control unit detects whether the braking function of the braking unit can be judged to be invalid or not; if yes, feedback torque control braking is carried out based on the maximum allowable feedback torque and the feedback target torque sent by the braking unit; and if not, the motor control unit acquires the state of the brake lamp switch, and if the state of the brake lamp switch is in an on state, feedback torque control braking is performed based on the vehicle speed.
  2. 2. The method according to claim 1, wherein the method further comprises: Under the condition that the braking function of the braking unit is normal, if the braking unit determines a target condition, performing closed-loop control according to a target deceleration corresponding to the depth of a brake pedal; the target condition comprises the fact that whether the feedback braking function of the motor control unit is effective or not can not be judged, or the feedback braking function of the motor control unit is invalid.
  3. 3. The method according to claim 2, wherein the method further comprises: And if the braking unit does not receive the message sent by the motor control unit within the second time period or the message sent by the motor control unit is abnormal, determining whether the feedback braking function of the motor control unit is effective or not.
  4. 4. The method of claim 2, wherein the brake unit comprises a dual brake circuit; the braking function of the braking unit is normal, namely, the double braking circuits are normal, or the single braking circuit of the braking unit is invalid.
  5. 5. The method of claim 4, wherein the closed loop control based on the target deceleration corresponding to the brake pedal depth comprises: Under the condition that the double brake circuits are normal, performing closed-loop control according to a first target deceleration corresponding to the depth of a first brake pedal; Under the condition that a single brake circuit of the brake unit fails, performing closed-loop control according to a second target deceleration corresponding to a second brake pedal depth; Wherein the second target deceleration is greater than the first target deceleration in the case where the first brake pedal depth and the second brake pedal depth are the same.
  6. 6. The method according to claim 2, wherein the method further comprises: in the process of performing feedback torque control braking based on the vehicle speed, if the motor control unit determines that the vehicle is about to slip backward, stopping performing feedback torque control braking before the vehicle slips backward; and in the process of performing closed-loop control according to the target deceleration corresponding to the depth of the brake pedal, if the vehicle is determined to be backward sliding, stopping performing closed-loop control before the backward sliding of the vehicle occurs.
  7. 7. The method according to any one of claims 1 to 5, further comprising: and if the motor control unit determines that the braking unit fails, performing feedback torque control braking based on the maximum allowable feedback torque and the feedback torque sent by the braking unit.
  8. 8. A computer-readable storage medium, characterized in that a vehicle braking program is stored thereon, which, when executed by a processor, implements the vehicle braking method according to any one of claims 1 to 7.
  9. 9. A vehicle comprising a memory, a processor and a vehicle braking program stored on the memory and operable on the processor, the processor implementing a vehicle braking method according to any one of claims 1 to 7 when the vehicle braking program is executed.
  10. 10. A vehicle is characterized by comprising a braking unit, a motor control unit and a brake lamp switch, wherein the motor control unit is used for: under the condition that the feedback braking function of the motor control unit is normal, if the braking function of the braking unit cannot be judged to be invalid, acquiring the state of the brake lamp switch; If the state of the brake lamp switch is determined to be an on state, feedback torque control braking is performed based on the vehicle speed; If the motor control unit does not receive the message sent by the braking unit within the first duration or the message sent by the braking unit is abnormal, determining whether the braking unit fails or not; The motor control unit detects whether the feedback braking function of the motor control unit is normal or not; If yes, a first effective prompt message is sent to the braking unit, wherein the first effective prompt message is used for indicating that the feedback braking function of the motor control unit is normal; if not, the motor control unit sends first failure prompt information to the braking unit, wherein the first failure prompt information is used for prompting that the feedback braking function of the motor control unit fails; the motor control unit detects whether the braking function of the braking unit can be judged to be invalid or not; if yes, feedback torque control braking is carried out based on the maximum allowable feedback torque and the feedback target torque sent by the braking unit; and if not, the motor control unit acquires the state of the brake lamp switch, and if the state of the brake lamp switch is in an on state, feedback torque control braking is performed based on the vehicle speed.

Description

Vehicle and braking method and device thereof Technical Field The application relates to the field of vehicles, in particular to a vehicle and a braking method and device thereof. Background The problems of energy crisis, environmental pollution, greenhouse effect and the like are increasingly serious, so that new energy automobiles, particularly pure electric automobiles, become the necessary trend of automobile industry revolution. The pure electric automobile uses the motor as a power source, and meanwhile, the motor can convert the kinetic energy of the automobile into electric energy for recovery, so that a decelerating braking effect is realized on the motion of the automobile. Disclosure of Invention The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, an object of the present invention is to provide a vehicle braking method, in which, when the motor control unit cannot determine whether the braking function of the braking unit is disabled and determines that the state of the brake light switch is on, feedback torque control braking can be performed based on the vehicle speed, so that the risk of accident of a passenger during riding is reduced, and the reliability of vehicle braking is improved. A second object of the present invention is to propose a computer readable storage medium. A third object of the present invention is to propose a vehicle. The vehicle braking method comprises the steps that under the condition that the feedback braking function of a motor control unit is normal, if the motor control unit cannot judge whether the braking function of the braking unit is invalid, the state of a brake lamp switch is obtained; and if the state of the brake lamp switch is determined to be an on state, feedback torque control braking is performed by the motor control unit based on the vehicle speed. In some embodiments of the present invention, if the motor control unit does not receive the message sent by the brake unit within the first duration, or if the message sent by the brake unit is abnormal, it is determined that whether the brake unit fails cannot be determined. In some embodiments of the present invention, if the braking function of the braking unit is normal, the braking unit performs closed-loop control according to a target deceleration corresponding to a depth of a brake pedal if a target condition is detected, where the target condition includes that whether a feedback braking function of the motor control unit is valid or not cannot be determined, or that the feedback braking function of the motor control unit is invalid. In some embodiments of the present invention, if the braking unit does not receive the message sent by the motor control unit within the second duration, or if there is an abnormality in the message sent by the motor control unit, it is determined that the feedback braking function of the motor control unit is not valid. In some embodiments of the invention, the brake unit includes dual brake circuits, and the braking function of the brake unit normally includes both dual brake circuits being normal or a single brake circuit of the brake unit being disabled. In some embodiments of the invention, controlling vehicle braking includes performing closed-loop control according to a first target deceleration corresponding to a first brake pedal depth in the event that both brake circuits are normal, and performing closed-loop control according to a second target deceleration corresponding to a second brake pedal depth in the event that a single brake circuit of a brake unit fails, wherein the second target deceleration is greater than the first target deceleration in the event that the first brake pedal depth and the second brake pedal depth are the same. In some embodiments of the present invention, the motor control unit stops performing the feedback torque control braking before the vehicle is coasted if it is determined that the vehicle is about to be coasted during the feedback torque control braking based on the vehicle speed; and the brake unit stops the closed-loop control before the backward running of the vehicle occurs if the backward running of the vehicle is determined to occur in the process of performing the closed-loop control according to the target deceleration corresponding to the depth of the brake pedal. In some embodiments of the present invention, the motor control unit performs feedback torque control braking based on the maximum allowable feedback torque and the feedback torque transmitted from the brake unit if it is determined that the brake unit fails. A computer-readable storage medium according to an embodiment of the present invention has stored thereon a vehicle braking program which, when executed by a processor, implements the vehicle braking method described above. The vehicle according to the embodiment of the invention comprises a memory, a processor and a vehicle b