Automatic Anti-Sway Control Study On Quayside Container Crane

To improve the port efficiency and enhance the development of modern logistics, the realization of synchro control of trolley positioning and payload anti-sway of quayside container crane is a primary problem to be solved. Currently methods such as mechanical anti-sway means and electronic anti-sway means are commonly applied to harbor cranes. Actually, the reliability of mechanical means is poor and the control effect is not ideal, meanwhile the electronic means greatly depends on the accuracy of the mathematical model. As the conventional PID controller which widely used has poor adapability to the operating condition and that can't tune its parameters online to meet the live change of the system.Aiming to the actual running features of the quayside container crane, this paper establishes the dynamical equation of the anti-sway system using langarange equation belonging to generalizied coordinates of analyitic mechanics. The stability, controllability and observability of the mathematical model are verified by using state space description. The paper designs a conventional PID controller to position trolley and a conventional PD controller to reduce payload sway by means of computer software Matlab/Simulink. The response results prove conventional PID controller basically meets control requirements, but which isn't suitable for controlled system whose working condition is time-varying.Quayside container crane is a complex system integrated with nonlinearity, time- variance, nondeterminacy and strong coupling performance. To overcome the application limitation of conventional PID controller, the paper adopts the merit of fuzzy control that doesn't depend on mathematical mode, using fuzzy language rules to tune PID parameters online, and provides the parameters online tuning rules. Thus, a fuzzy self-adaptive PID controller for trolley position and a fuzzy self-adaptive PD controller for payload anti-sway are designed. The response results prove fuzzy self-adaptive PID controller has high control accuracy and strong adaptability to varying work conditions.The disturbance test with varying parameters and external disturbance singals states, through changing the length of main hoist rope and payload mass as well as the introduction of disturbances, under the control of fuzzy self-adaptive PID controller, the overshoot caused by the step response of trolley displacement can be greatly reduced, and the maximum swaying angle of payload is also obviously reduced, thus the dynamic performance of the system is obviously improved; while under the control of conventional PID controller, the overshoot of the system is comparatively larger. Seen from the index of the dynamic performance, fuzzy self-adaptive PID controller has better dynamic/static performance and robustness, which has better practical potential.