While operating the crane, the crane operator needs to make sure that there is very less crane
swing while moving the load. The swinging of the crane takes place when the crane is moving in
one direction very fast and due to this, the momentum forces it to moves back and forth. This
can create a very dangerous situation on a worksite.
To avoid this kind of situation, Anti-Sway Control is used to monitor and control the crane
movement. Anti-Sway control controls the speed of the motor through PLC.
Working of the Anti-Sway Control
When the operator sends the command to the crane, the anti-sway
control translates the operator command into timed acceleration patterns. Then these timed acceleration
patterns are transmitted to the EOT crane’s PLC in the real-time. This pattern varies slightly from the
operator’s stick control or a simple speed ramp. There is a small difference in these pattern and
operator’s command so that it can avoid the swaying from the motion of the trolley.
If in any situation, the operator moves the control at a full speed, then the anti-sway control will
accelerate initially according to the operator’s demand, and will also induce the initial load sway.
When half the reference velocity has been reached, the anti-sway maintains the constant velocity for
a short time. Then this time the trolley is accelerated again by the operator’s command velocity.
This another acceleration eliminates the sway which is induced by the first acceleration.
trolley is travelling at the operator command’s velocity, along with the load hanging below the trolley.
When the operator releases the stick for zero velocity, then the same process is repeated in reverse,
so that we can stop the movement without any sway. If the operator wants movement for a short time,
the anti-sway control will stop the motion and then perform the second movement to catch the sway.
All this operation requires precise and accurate timing, that is dependent on the natural frequency
of the pendulum motion. The anti-sway carefully manages the changes in hoist cable length, changes
in the operator’s command, etc. in the real-time.
Rather than using the real-time sway measurement and control feedback, the main features of the
anti-sway control use the precise timing of acceleration to control the sway.
However, when we need to eliminate the sway that has to occur because of wind or non-vertical lift
factor, the anti-sway control will measure and correct the actual sway in the real-time, usually at
the end of a move, within user-selected tolerances.
The implementation of the closed-loop anti-sway control system will prevent the load swing from a
manual error such as the wrong alignment while lifting the load, and external influences such as wind
load. It offers safety in the working environment.Please Call on 9137620579 for more Details.