The Research Of Dynamic Sliding Mode Anti-swing Control Methods For Overhead Cranes

Bridge cranes are mechanical equipment used to transport materials and are widely used in ports,warehouses,and large-scale construction projects.When the bridge crane carries materials,due to the inertia of the operating mechanism,the load is oscillated,which affects the work efficiency and poses a safety hazard.The dynamic sliding mode control method is simple to implement,fast in response,does not require online identification of the system,and can attenuate the chattering phenomenon of the traditional sliding mode control while ensuring the robustness of the system,and has a good control effect on the underactuated nonlinear system.Therefore,based on the dynamic sliding mode control method,this paper combines with other control methods to design the controller to solve the problem of positioning and anti-swing in the operation of the bridge crane.Firstly,a dynamic sliding mode controller is designed for the fixed length nonlinear crane system.The RBF network is used to approximate the uncertainties in the first derivative of the control input.At the same time,the adaptive law is designed to ensure the asymptotic stability of the system.The obtained dynamic sliding mode control method of RBF network does not depend on the system model,and when there are uncertainties in the system,the control effect is better.Secondly,the mathematical model of the fixed length nonlinear bridge crane system is transformed,and the error state equation of the system is obtained,which is decomposed into three subsystems.The virtual control quantity and feedback control law are designed for each subsystem by using the reverse step method.The backstep control error is obtained,and then the Lyapunov function is designed layer by layer to realize the stability of each subsystem,and the dynamic sliding mode surface is constructed to converge the system’s backstepping control error to zero,and the discontinuous control force derivative is obtained.Then,the obtained discontinuous control force derivative is integrated to obtain a continuous control force in time,which reduces thechattering,and the control method has good stability and high control precision.Finally,a global fast dynamic sliding mode controller is designed for the mathematical model of variable length nonlinear crane system.The two linear sliding mode surfaces containing the displacement swing angle variable and the rope length variable are recombined by the differential link,and the terminal attractor is added to form a new global fast dynamic sliding surface.The sliding mode surface is related to the first derivative of the control input,so that the first derivative of the control input contains discontinuous terms,thereby obtaining a control force that is continuous in time,effectively weakening the chattering.And the controller can make the system state variable converge to the equilibrium state in a limited time,and the rapidity is better.