Anti-sway tracking control for a pendulum-trolley system via singular perturbation technique

Problem of anti-sway tracking control for an overhead crane is treated based on a pendulum-trolley system. The control system is designed in order to provide the sway-free horizontal displacement of a crane's load. The proposed control system consists of two feedback loops where in the first control loop the sway angle proportional-integral-derivative (PID) control is provided by means of the force applied to the trolley in the horizontal direction. In the second one the horizontal movement of the trolley is governed by the tracking PID controller in accordance with the desired velocity profile. Singular perturbation technique (time-scale separation method) is used for control system design. The effect of the velocity profile variation on the closed-loop system behavior is investigated. Numerical simulation results are presented.