Method for achieving gradient keeping through combination of VCU crawling torque control and EPB parking

Abstract

The invention discloses a method for achieving gradient keeping through combination of VCU crawling torque control and EPB parking, and the method comprises the following steps: in a Ready state, releasing a hand brake, and starting to release a brake pedal, enabling crawling PID control, and starting to output torque; the EPB gradually reduces the braking torque output by the EPB according to the signal sent by the VCU and the feedback torque value of the driving motor, and when the driving torque of the motor is larger than the braking torque of the EPB, the EPB completely cancels the braking force; when the VCU outputs the torque, whether the rotating speed of the motor is matched with the gear or not is detected through the VCU; a PID feed-forward torque and a PID coefficient of a slope sliding state are looked up through VCU detection data; according to the detected feedforward torque and the PID coefficient, the torque output of the VCU is seamlessly switched from the creeping torque to the torque calculated by the gradient keeping strategy; during uphill driving, after a driver steps on an accelerator pedal and starts to accelerate, the crawling and gradient keeping strategy exits; according to the invention, the stability of the vehicle during starting or backing on the ramp is ensured, and the possibility of sliding on the ramp is reduced.

Description

technical field [0001] The invention relates to a method for realizing slope maintenance by combining VCU creeping torque control with EPB parking, and belongs to the technical field of driving gradient maintenance. Background technique [0002] The driving torque control of pure electric vehicles is controlled by the VCU (Vehicle Controller). When the car is at low speed, there is no accelerator pedal opening, and the brake opening is less than a certain value, the VCU enters the creep PID control mode according to the current state of the car, and makes the car automatically creep forward or backward according to the gear position. When the driver is driving uphill or reversing downhill, the driver's operation is to step on the brake to release the handbrake, and then release the brake to step on the accelerator. During the process of stepping on the accelerator, the car does not move towards The front driving torque and no braking force will cause a slippery slope. [0...

AI Technical Summary

Problems solved by technology

[0003] In the existing technology, the creep and slope maintenance strategies are separated, and there is no way to take the creep and slope maintenance strategies into consideration in the control strategy, and in order to maintain the slope, the creep torque control will make the torque gradient larger

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