FAQ >> Classification of Crane Anti-sway devices

Classification of Crane Anti-sway devices

Crane anti-sway systems come under three main categories:

  • passive systems: cables attached to the load prevent it from swaying,
  • active closed loop systems where the swaying angle is measured with a camera connected to an image processing system,
  • active open loop systems where the information is obtained without additional sensors, from the information available.
The first system entails mechanical complexity and permanent maintenance. The second requires costly auxiliary systems and case by case adjustment. The third is by far the simplest and the easiest to implement. The Anti-Sway solution, provided by Schneider Electric, belongs to this last category. It provides a powerful, economic, maintenance-free response with no need to modify equipment. The originality of this approach is that it works without measuring the actual swaying, by means of an estimator embedded in a drive controller or any external logic controller. The principle is that the anti-sway controller calculates an acceleration (a progressive speed profile) that enables the lifting equipment to reach a given movement speed without the load swaying. Since there is no way to determine the actual state of the physical system, proper operation requires a zero initial swaying and insignificant external disruptions, such as wind. The installation of an active open loop anti-sway system has an undoubted economic advantage compared with a closed loop system.

Relative FAQ