Coordination control method and device for auxiliary braking gear shifting

The invention relates to the field of vehicle auxiliary braking, in particular to a coordination control method and device for auxiliary braking gear shifting, and the method comprises the steps that when a vehicle is in a preset specific working condition, auxiliary braking gear shifting is activated; the method comprises the steps that a target gear of auxiliary braking gear shifting is automatically determined, the corresponding motor rotating speed and the corresponding regenerative braking torque of a gearbox output shaft are obtained according to the current gear of a vehicle and the target gear, and whether gear shifting is conducted or not is judged according to the regenerative braking torque and the motor rotating speed; under the condition that gear shifting is determined, braking and gear shifting are carried out through a motor, a mechanical brake and a gearbox on the premise that the deceleration of the vehicle is kept unchanged. When the vehicle is in the specific working condition, auxiliary b