Control method of electrical power steering system

The invention provides a control method of an electrical power steering system with a side safety auxiliary function, which aims to reduce the side collision rate of automobiles and guarantee the traveling safety. The electrical power steering system comprises an electronic control unit, and is characterized in that the electronic control unit is connected with a position/torque sensor of a steering wheel, a speed sensor, a speed acceleration sensor, a power motor and a current sensor thereof, a yaw velocity sensor and a side acceleration sensor. The power motor is connected with a steering mechanism of the automobile through a driving mechanism. The electronic control unit is also connected with distance testing sensors which are arranged at both sides of the automobile. On the basis that the traditional electrical power steering system provides the basis function of power-assisted steering for drivers, the invention also increases the function which uses the steering wheel torque to alert the side collision danger, uses the power motor to implement warning and danger elimination, is favorable for avoiding the automobile generating side collision with the objects at both sides, and increases the traveling safety.