Positioning And Anti-Disturbance Control Of The Double-Pendulum Overhead Crane Based On Disturbance Observer

In recent years,underactuated systems are increasingly used in industrial fields,and their control problems have also attracted the considerable attention of many scholars from the control community.As a typical underactuated system,the overhead crane system has been extensively used in iron and steel chemical industry,railway transportation,port and other industrial places for its merits such as high efficiency,large carrying capacity,low energy consumption,and so on.Similar to other underactuated systems,the number of control variables of the overhead crane system is less than the number of system degrees of freedom,which makes the control problem for the overhead crane system challenging.So far,many achievements have been derived for the control research of overhead crane systems.However,most of the existing control methods are developed based on the single-pendulum overhead crane systems.In the practical overhead crane system,the load is usually connected to the hook through a steel cable and the hook mass is large,thus,the distance between the hook and the load and the hook mass cannot be ignored.In this case,the overhead crane system exhibits double-pendulum characteristic.When the controller designed based on the single-pendulum overhead crane system is applied to the double-pendulum overhead crane system,the control performance will be greatly reduced and even makes the controller invalid.Therefore,the research of the control for double-pendulum overhead crane systems has very important practical value and theoretical significance.This thesis mainly studies the positioning control and anti-disturbance control of the double-pendulum overhead crane system.The main research contents are summarized as follows:An enhanced anti-swing control method is proposed for overhead crane systems.Compared with the methods developed for single-pendulum overhead crane systems,the proposed method have more practical applicability.Firstly,some basic transformations of the system dynamics are made,and the acceleration variable is regarded as the control input to be designed.Then,a Lyapunov function is proposed and a nonlinear antiswing control method is designed.Next,the stability of the closed-loop system and the convergence of the system state are proved by Lyapunov theory and La Salle invariance principle.Finally,the effectiveness of the proposed method is verified in the simulation platform.A disturbance-observer-based method is proposed for the double-pendulum overhead crane system with unknown disturbances.Compared with traditional sliding mode control methods,the proposed method is a continuous control method,which can effectively solve the chatting problem.Firstly,a finite time disturbance observer is proposed based on the system dynamics equation.Subsequently,a Lyapunov function is constructed and a nonlinear control method is designed based on the proposed finite time disturbance observer.Then,theoretical analysis is given to prove the the stability of the closed-loop system and the convergence of the system state.Finally,simulation tests are made in the simulation platform,the simulation results show that the proposed method has good robustness.A disturbance-observer-based output feedback method is proposed for the doublependulum overhead crane system with unknown disturbances.Compared with the existing anti-disturbances control methods,the proposed controller considers both input saturation and output feedback,which improves the practical applicability.Firstly,a finite time disturbance observer is proposed based on the system dynamics equation.Subsequently,a Lyapunov function is designed and a output feedback control method is proposed.Finally,theoretical analysis and simulation tests are made to verify the effectiveness and robustness of the proposed method.