The traditional positioning method of the crane is to install the absolute value encoder on the drive shaft of each mechanism, and the absolute value encoder converts the rotation of the shaft into the moving distance to the control system, and the control system judges whether the equipment is in place. The positioning accuracy of intelligent crane is higher than that of traditional crane, there are many factors affecting the positioning accuracy, and different accuracy requirements for positioning systems are not the same.

The absolute value encoder of the lifting mechanism is generally installed on the high-speed shaft of the reducer or the tail shaft of the drum, while the absolute value encoder of the operating mechanism is installed on the tail of the three-in-one reducer motor or the tail of the wheel shaft. On the intelligent crane, when the positioning accuracy is required to be within ± 5mm, the positioning of the operating mechanism often deviates. The reasons for affecting the positioning accuracy are as follows; The active wheel occasionally slips slightly, and the wheel shaft rotates but does not actually shift, which causes the positioning system to be unstable. Due to the difference between the height of the track, a wheel and the track do not contact within a short distance, which mostly occurs at the passive wheel, but may also occur at the active wheel, when the wheel momentum and displacement are no longer corresponding; Affected by the quality of the track, the absolute encoder has its own problems in the active and passive axle, so the traditional positioning device can not meet the requirements of the intelligent crane. In the intelligent crane can replace the absolute encoder positioning of the rack and pinion positioning system, cable encoder system, bar code positioning system, etc., these systems can be more accurate to complete the positioning of the crane.