The elevator is a kind of vertical elevator powered by a motor, equipped with a box-shaped pod, used for multi-storey buildings to take people or carry goods. There is also a stepped type, the stepper is installed on the track to run continuously, commonly known as the escalator or moving walk. Fixed lifting equipment serving the specified floors. The vertical elevator has a car that runs between at least two rows of vertical or rigid guide track with an inclination angle of less than 15°. The size and structure of the car are convenient for passengers to enter and exit or load and unload goods. It is customary to regard elevators as the general term for vertical transportation vehicles in buildings regardless of their driving methods. According to the speed, it can be divided into low-speed elevators (below 1 m/s), fast elevators (1 to 2 m/s) and high-speed elevators (above 2 m/s).