Stability Control For The Under-actuated Tower Crane Systems

As a typical under-actuated mechanical system,compared with full-actuated mechanical system,the tower crane system meets that the number of its independent control variables are less than the number of its degrees of freedom.The reduction of the independent control variables lead to the reduction of the number of actuators,so as to the design cost of the control system and it will be more flexible.There are great limitations between the traditional artificial control,which exists uncertainties and errors during the process of operation.Therefore,in order to improve the work efficiency and safety of the system,a safe and effective automatic control strategy is urgently needed to take the place of the manual control.In this paper,based on the double-pendulum tower crane systems,and combined with the actual project situations,a few automatic control methods were proposed.The core work of this paper is mainly focused on the following aspects:Firstly,a detailed introduction to the present development of the under-actuated mechanical system is given,including the subject source,background and the research significance.By reviewing the research work of the domestic and foreign experts and scholars on the under-actuated crane system,an improvement and innovation in the control algorithm based on the existing control strategy in this article was involved.Secondly,based on the Euler-Lagrange modeling method,the double-pendulum tower crane dynamic equations were established.In view of the trolley moves along the tower crane jib,which the trolley is only driven by a horizontal force,established its dynamics and its space equation.Thirdly,according to the dynamic equations in the second chapter,a passive controller of the double-pendulum tower crane and a speed fitting speed fitting are designed since the speed variables are hard to measure.Then the simulations and the experimental results verify its validity.Fourthly,considering the complexity of the work environment of the tower crane,it may be hard or even impossible for us to build a precise mathematical model.So,it is necessary to design a controller to solve the problem.For this reason,a fuzzy weighting algorithm is adopted through observation of the relations between the system's input and output and the engineering experience.The fuzzy control rules were designed which is much simpler compared with the traditional one.Then the simulations and the experimental results verify the validity of the method.Fifthly,a sliding mode controller and a PID controller are proposed for the operation in which trolley moves along the tower crane jib.A Virtual-Reality software(VR)and a Graphical User Interface software(GUI)were designed,which make the simulations and experimental results more intuitive and obvious.Finally,summarized the main work of the study and look forward to future research directions.