Research On Anti-swing Control Strategy Of Crane Spreader Based On Input Shaping Technology

The key to the efficient operation of bridge crane is to design the anti-swing and positioning control system of the spreader.At present,the commonly used anti-swing positioning control methods of the spreader include manual anti-swing,mechanical anti-swing and electronic anti-swing.With the prosperity of automation of cranes,electronic anti-swing method has become the most widely used anti-swing method due to its advantages of low cost and high control precision.However,in the process of designing the electronic anti-swing controller,the problems such as the high nonlinearity of the controlled object model,the strong coupling and underactuation of the system,as well as the external disturbance,etc.have brought great challenges to the design of anti-swing positioning control system.Therefore,the rational use of control methods to design a stable and fast anti-sway control system of crane spreader has important theoretical significance and practical value for improving the positioning accuracy of crane spreaders and improving the efficiency of loading and unloading transportation.In view of the above problems,this paper takes the design of the anti-sway positioning controller of the port bridge crane spreader as the research content,in order to propose a method for the anti-sway active control of the spreader,and does the profound research in improving the positioning accuracy of the spreader and the system robustness,the main work completed are as follows:(1)The first task in designing the anti-swing positioning control system of crane is to establish the dynamic model of the system.Firstly,the two-dimensional model of crane hoisting is the basis for the establishment of dynamic model,and the stress of the model needs to be comprehensively analyzed;secondly,the nonlinear dynamic model of the system is established according to the Lagrange principle;At last,the linear dynamic equation is established by a simplified method of small-angle approximate treatment,which provides a theoretical basis for verifying the effectiveness of the active controller of anti-rocking positioning of slings.(2)The input shaping technique has a simple structure,and it has remarkable control effect to restrain the swinging of spreader.It is the first choice method to design anti-swing controller of crane spreader.The anti-swing and positioning controller is designed by the combination of input shaping technology and PID feedback control.This method not only effectively reduce the residual swing of the spreader,but also let the system have good anti-interference.Firstly,Zero Vibration(ZV),Zero Vibration and Vibration(ZVD)and Extra Insensitivity(EI)anti-vibration controller are designed based on the principle of input shaping technology.The simulation experiment is used to verify the effectiveness of these controllers in suppressing residual swing of lifting load;Secondly,the anti-swing and positioning control law of bridge crane is PID-ZVD control law,which is designed according to PID feedback control method;Finally,simulation experiments are used to verify the anti-swing and positioning control effects of ZVD,PID and PID-ZVD controllers.Simulation results show that the PID-ZVD anti-swing controller can effectively suppress the residual swing of the spreader and accurately track the set position of the trolley.In addition,after the addition of external disturbance,the controller has a good disturbance rejection ability.(3)The method of using predictive control instead of PID feedback control to design anti-swing positioning controller is proposed to solve the problem of actuator saturation caused by large output of PID-ZVD anti-swing positioning controller.Firstly,based on the feature that predictive control has the ability to explicitly handle system constraints,generalized predictive control(GPC)and predictive function control(PFC)algorithms are respectively applied to design the anti-roll positioning controller of the crane hoist within the reasonable constraint range of control output.The simulation experiment compares the control performance of these two control algorithms.The experimental results show that the PFC anti-sway controller has a small amount of calculation,high control accuracy,and good disturbance rejection ability.It is the preferred method to replace PID feedback control;then,the anti-swing positioning controller is designed by combining the PFC control algorithm with the input shaping ZVD technology,based on the characteristics of the input shaping ZVD technology to effectively suppress the swing of the spreader.Through simulation experiments,it is found that this method can accurately track the position of the trolley and effectively restrain the swing of the spreader within the effective range of the actuator.(4)Most of the cranes will be interfered during the operation process,which not only affects the accuracy of system modeling,but also affects the control performance of the system.How to reduce the impact of external disturbance on the control system is the last content to be studied.In order to solve the disturbance problem,a method is proposed,which uses the exponential convergence observer and the Extended state observer(ESO)to design anti-swing and positioning controllers.The controller constitutes internal loop of the system to suppress disturbance.The disturbance estimator of the disturbance observer is introduced into the PFC anti-swing and positioning controller which combines the input shaping technology.The controller is the external loop of the system.This control scheme is the most direct active anti-jamming strategy,which improves the robustness of anti-swing and positioning controllers.A large number of simulation experiments have verified that the active control strategy can achieve the target of the anti-swing positioning control,and improve the robustness and anti-interference of the system,and improve the stability and rapidity of the system.