Controlling method for an actuator, actuator, and electromechanical brake system

A controlling method for an actuator upon braking during driving, the actuator comprising an electric motor with a shaft and a brake force holding device capable of locking the shaft, the controlling method comprising:

• receiving a brake demand;
• controlling the electric motor based on the brake demand;
• if the brake demand satisfies a preset stationary condition within a preset period, controlling the brake force holding device to lock the shaft during driving;
• wherein a desired electric motor rotated position of the electric motor is generated dependent on the brake demand;
• wherein the preset stationary condition includes that:
• the desired electric motor rotated position within the preset period is always located within a preset stationary zone;
• wherein driving comprises all operation states of a vehicle in which the vehicle is in motion;
• and
• wherein dynamic adjustment is performed to the preset stationary condition dependent on factors including a vehicle load, a vehicle speed, a slip ratio, a brake disc temperature, and a brake pad wear.