Residual Oscillation Suppression of a Tower Crane Cargo by Monotonized Swinging Motion in Constant Velocity Rotation

Abstract

Numerical simulation of a tower crane cargo was performed to identify a velocity pattern by which residual oscillation was suppressed. Residual oscillation was sufficiently suppressed using a simple trapezoidal velocity pattern when a cargo's trajectory of swinging motion was symmetrical. A skilled operator, however, intentionally changes the swinging motion in the acceleration to monotonize the resultant swinging motion in the constant velocity rotation. Two-stage angular velocity pattern was then adopted to simulate manipulation of the skilled operator. Three parameters A, k and n value which determine the two-stage velocity pattern should be properly selected to suppress residual oscillation. A and k value was numerically determined and n value was analytically determined. Monotonic swinging motion in the constant velocity rotation was obtained under the particular velocity pattern. Deceleration timing to suppress residual oscillation was periodically obtained due to the monotonized swinging motion. The applicability of the proposed process optimized method was investigated by means of a scale model experiment. Numerical and experimental results showed well agreement in which residual oscillation of a tower crane cargo was sufficiently suppressed.