Hill starting control method for pure electric commercial vehicle based on real-time mass identification

Abstract

The invention belongs to the field of control of commercial vehicles, and particularly relates to a hill starting control method for a pure electric commercial vehicle based on real-time mass identification. The hill starting control method comprises the following steps: judging whether the vehicle enters a hill starting mode or not; calculating hill gradient and vehicle mass after the vehicle enters the hill starting mode; and before an accelerator pedal is stepped on, keeping the vehicle static under the action of hydraulic braking force. After the accelerator pedal is stepped on, the sum ofdriving torque and braking torque is equal to hill equivalent torque; when motor torque is greater than motor stalling torque, the vehicle does not start, a motor controller controls the motor torquenot to increase along with the increase of the opening degree of the accelerator pedal until the opening degree of the accelerator pedal is increased to the state that the torque is greater than thehill equivalent torque, and braking torque is quickly removed. According to the method disclosed by the invention, after the accelerator pedal is stepped on, the motor driving torque, the braking torque and the hill equivalent torque are balanced, and thus, the circumstances that the motor is blocked and the vehicle moves suddenly and slips during starting are avoided.

Description

technical field [0001] The invention belongs to the field of commercial vehicle control, and in particular relates to a ramp-start control method for pure electric commercial vehicles based on real-time quality identification. Background technique [0002] Regarding the hill start assist control method for pure electric commercial vehicles, the main methods currently used include: after the brake pedal is released, the brake applies a braking torque to prevent the car from rolling, and after the accelerator pedal is stepped on, the brake is removed after a certain period of time. moment. If the above method is not properly controlled, three abnormal situations will occur: the first one, remove the braking torque after a certain period of time, if the driving torque is too large, there will be a phenomenon of running away, causing a safety hazard; the second one, if you step on The opening of the accelerator pedal is not large enough, the driving torque is insufficient, and ...

AI Technical Summary

Problems solved by technology

If the above method is not properly controlled, three abnormal situations will occur: the first one, remove the braking torque after a certain period of time, if the driving torque is too large, there will be a phenomenon of running away, causing a safety hazard; the second one, if you step on The opening of the accelerator pedal is not large enough, the driving torque is insufficient, and the car will slide; the third type, if the opening of the accelerator pedal is too large, the driving torque exceeds the motor stall torque, and the braking force of the brake has not yet become 0 at this time. , will damage the motor

[0003] Patent Document 1 (CN106904158A) discloses a hill-start assist control method for pure electric vehicles, including the following strategy: after the brake is released and before the brake is stepped on, the braking torque is used to park, and when the accelerator pedal is stepped on, the braking torque Change to 0, use the driving torque to start on the slope, and at the same time add that when the torque of the driving motor exceeds the stall torque, the motor controller limits the torque until the corresponding torque of the accelerator pedal is greater than the equivalent torque of the slope, the motor control The torque limiter cancels the torque limit, allowing the vehicle to start, and solves the problem of motor damage when the motor torque exceeds the stall torque

However, for the system disclosed in Patent Document 1, after the accelerator pedal is stepped on, the brake will remove the braking torque after a certain period of time. If the driving torque is too large, there will be a car-running phenomenon, causing a safety hazard. If it is not big enough, the driving torque will be insufficient, and the car will slide. If the accelerator pedal is opened too much, the driving torque will exceed the motor stall torque, and the braking force of the brake has not become 0 at this time, which will damage the motor.

[0004] To sum up, the existing control system cannot make the vehicle start smoothly on the slope, so that the vehicle will neither run away nor roll, and will not cause the motor to stall at the start stage.

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