DESIGN OF FUZZY LOGIC CONTROLLER FOR ANTI-SWAY CONTROL OF TOWER CRANE UNDER DISTURBANCE

Abstract

Tower cranes are widely used in constructions and loading unloading systems due to restricted human capability to transport numerous types of loads. Furthermore, in order to transport the load in minimum time from one position to another, load oscillation or sway angle will occur. This undesirable sway causes inaccurate positioning of the load, longer time of task completion, difficult automation by the human operator and damage to the system or the operating environment. This thesis presents the design of optimal motion planning, PID controller and fuzzy logic controller (FLC) for the sway angle control of tower crane system with friction. The optimal motion planning is an algorithm to determine optimal time for acceleration, constant velocity, and deceleration for trolley and jib motions when they are driven under trapezoidal velocity time curve. This algorithm considers the trolley and jib initial positions, final positions and system nature. The Newton’s second law is used to drive the mathematical model of tower crane or rotary crane system and the simulation results are done using MATLAB/Simulink environment. Simulation results are presented in trolley and jib optimal time trajectory tracking capability and load sway angle reduction. The FLC is compared with the classical PID controller in terms of the trolley and jib optimal time velocity, acceleration, magnitude of sway angle, rate of change of sway angle and displacement profile tracking performance under the effect of various trolley displacements. It has been seen that the fuzzy logic controller gives better performance in minimizing the sway angle and tracking the optimal time references of tower crane system than the classical PID controller.