Fuzzy Control of a Large Crane Structure

Abstract

The usage of tower cranes, one type of rotary cranes, is common in many industrial structures, e.g., shipyards, factories, etc.  With the size of these cranes becoming larger and the motion expected to be faster and has no prescribed path, their manual operation becomes difficult and hence, automatic closed-loop control schemes are very important in the operation of rotary crane.  In this paper, the plant of concern is a tower crane consists of a rotatable jib that carries a trolley which is capable of traveling over the length of the jib.  There is a pendulum-like end line attached to the trolley through a cable of variable length.  A fuzzy logic controller with various types of membership functions is implemented for controlling the position of the trolley and damping the load oscillations.  It consists of two main types of controllers radial and rotational each of two fuzzy inference engines (FIEs).  The radial controller is used to control the trolley position and the rotational is used for damping the load oscillations.  Computer simulations are used to verify the performance of the controller.  The results from the simulations show the effectiveness of the method in the control of tower crane keeping load swings small at the end of motion.