Electronic power steering system, control method and device thereof and vehicle

The invention discloses an electronic power-assisted steering system, a control method and device thereof and a vehicle, and the control method of the electronic power-assisted steering system comprises the steps: obtaining a steering wheel torque signal and a whole vehicle speed signal under the condition that a whole vehicle ignition signal is abnormal; under the condition that the vehicle speed signal of the whole vehicle is abnormal and the change rate of the torque signal of the steering wheel is larger than a preset threshold value, the electronic power-assisted steering system is controlled to provide steering assistance based on the first preset vehicle speed; and under the condition that the whole vehicle speed signal is abnormal and the change rate of the steering wheel torque signal is smaller than or equal to a preset threshold value, the electronic power-assisted steering system is controlled to stop providing power-assisted steering. According to the control method of the electronic power-assist