Research On Anti-sway Technology Of Gantry Crane System

With the development of modern industry and international shipping trade,gantry cranes,as a large-scale construction machinery,play an important role in related fields.At present,it is mainly used to transport the load to the designated position quickly and accurately while reducing the load swing.At present,automated rail mounted gantry crane(ARMG)mainly uses the electronic anti-sway scheme.which can be further divided into open-loop anti-sway based on trajectory planning and closed-loop control based on PID control.The former often depends on the accuracy of the established mathematical model,while the latter is difficult to realize the real-time tracking of the dynamic performance of the system.However,the system degree of freedom is less than the dimension of the input control quantity.It is a typical under-driven system,and it can not directly control the movement of the load through external input,and the actual trajectory of the load is also vulnerable to environmental factors,such as wind and so on.On the other hand,each state variable is coupled with each other,and the system has strong nonlinearity,which also brings great challenges to the design of control system.In recent years,researchers in the field of control have carried out in-depth research on the anti-sway control of gantry crane,but the existing research results still have some deficiencies.According to the requirement of high-performance anti-sway positioning of a certain type of gantry crane,this paper designs a control system with high efficiency,full consideration of system performance and strong robustness from the perspective of engineering use.Specifically,the main research contents of this topic are as follows.Based on the Lagrange equation method,a three-dimensional dynamic model of gantry crane is established,which can accurately describe the dynamic characteristics of the system under ideal working conditions.It also lays the foundation for the subsequent design of control scheme based on this model,and analyzes the stability,controllability and other characteristics of the control system.Subsequently,the kinematics equation of the gantry crane system in this study is projected to the phase plane for analysis.A specific and analytical acceleration control strategy is proposed to ensure that the dynamic indicators of the system always meets the requirements.The paper verifies that the scheme has better control performance in theory through numerical simulation and numerical examples.Based on the control strategy proposed above,the influence of structural deformation and system vibration on crane positioning is further considered.Firstly,a dynamic model considering rope deformation and load size is established.The numerical simulation shows that the influence of crane system on anti-sway control strategy based on phase plane method is small.Then,considering the influence of inertia force and so on,the static analysis of the elastic mechanism of the crane structure is carried out.Based on the deformation of the structure,the movement track of the trolley is modified.Through the establishment of a flexible beam model for dynamic simulation,it is shown that it is necessary to modify the acceleration track of the gantry crane with flexible legs.In the end,the finite element model of gantry crane is established in Ansys,and the imported model is improved in Adams to complete the dynamic simulation.The simulation results fully show that the correctness of acceleration trajectory planning and the influence of gantry deformation and vibration on load positioning accuracy are within the allowable range.This paper analyzes the possible working conditions and problems in the actual working process of the crane.First of all,the motion analysis and anti-sway design under the condition of emergency braking are carried out.Through calculation,it is found that there is a maximum impact distance of the load during the braking process in the model with customized dynamic parameters.At the same time,a controller based on damping energy consumption is designed to restrain the swing of the load.Finally,in order to overcome the uncertainty of the load movement when the system is disturbed,a PID control system that can track the movement state of the system is designed.On this basis,a fuzzy adaptive PID controller is designed,which can be applied to many kinds of working conditions.And Adams-MATLAB joint simulation shows that the controller can greatly improve the robustness of the system.