Affiliations: Software Engineer, Intel Corporation, Santa Clara, CA
95053, USA | Department of Engineering Science and Mechanics, MC
0219, Virginia Polytechnic Institute and State University, Blacksburg, VA
24061, USA | Department of Bradley Electrical and Computer
Engineering, MC 0111, Virginia Polytechnic Institute and State University,
Blacksburg, VA 24061, USA
Abstract: Rotary cranes (tower cranes) are common industrial structures that
are used in building construction, factories, and harbors. These cranes are
usually operated manually. With the size of these cranes becoming larger and
the motion expected to be faster, the process of controlling them has become
difficult without using automatic control methods. In general, the movement of
cranes has no prescribed path. Cranes have to be run under different operating
conditions, which makes closed-loop control attractive. In this work a fuzzy logic controller is introduced with the idea of
"split-horizon"; that is, fuzzy inference engines (FIE) are used for tracking
the position and others are used for damping the load oscillations. The
controller consists of two independent sub-controllers: radial and rotational.
Each of these controllers has two fuzzy inference engines (FIE). Computer
simulations are used to verify the performance of the controller. Three
simulation cases are presented. In the first case, the crane is operated in the
gantry (radial) mode in which the trolley moves along the jib while the jib is
fixed. In the second case (rotary mode), the trolley moves along the jib and
the jib rotates. In the third case, the trolley and jib are fixed while the
load is given an initial disturbance. The results from the simulations show
that the fuzzy controller is capable of keeping the load-oscillation angles
small throughout the maneuvers while completing the maneuvers in relatively
reasonable times.
