Passive Anti Swing Bridge Crane And Positioning Control Method

Overhead cranes are widely used in ports, workshops, docks and warehouses and other industrial sites. Not only car need quickly move cargo to their destinations and rope length, displacement and etc are accurately positioned. But also, to avoid a collision, the load-swing angle is as small as possible and quickly is reduced to zero after reached. Affected by change of speed, wind, friction and other factors, loading or unloading cargo easily cause it’s swing, which reduces productivity and adds to security risk. Thus, to solve the problem of anti-swing and positioning, the research about anti-swing control method of overhead crane had become a hot issue. From the perspective of energy, this article had used the passive character of system, and combined with the advantages of fractional control theory, sliding mode control theory and filter methods and etc, to design controllers used in three-dimensional and two-dimensional overhead cranes svstems.Firstly, the study status of control method about anti-swing and positioning of overhead crane had been concluded and summarized. Based on the analysis of the structure of the bridge crane and the forces, Euler-Lagrange equation had been used to establish three-dimensional and two-dimensional dynamic model of overhead crane system. And the nonlinear characteristics of the system had been analyzed.Secondly, after the analysis of system about passive, the Control Lyapunov Function had been constructed to design a passive-based fractional controller. The controller had been applied to two-dimensional crane system which had been affected by friction. After a comparative analysis, the optimal order of the controller application range had been found. Then compared with the passive-based PD controller, the system had been found to have better performance.Again, for the three-dimensional overhead cranes, a passive sliding mode control method had been proposed. The feedback input compensation had been applied to the Euler-Lagrange error system to redefine the output signal and obtain the asymptotic convergence of the error signal. After the analysis about passive of system, the Control Lyapunov Function had been constructed to design a passive-based sliding mode controller(PBC-SMC). The controller had been applied to three-dimensional overhead crane system. The results had shown that the the system had obtained globally asymptotically stable, which had achieved the purposes of accurately positioning and effectively anti-swing.Finally, in order to improve on the dynamic property and robustness of the system, based on the former analysis, the low pass filter had been added to the output of sliding controller to obtain the low-pass PBC-SMC controller. The controller is applied to two systems, including a unvaried rope length one and a varied rope length one, to test the controller’s performance. Simulation results show that the residual shock had not appeared and the system has a better dynamic performance and stability.