Research On Stability Control Method For Vertical Lift-up And Transportation Process Of Slender-beam Payload

Crane is a material conveying equipment widely used in the fields of harbor marina,production workshop,road and bridge construction,aerospace and so on.In the process of lifting and transportation,the vertical lift-up and transportation of slender-beam payloads such as metal bars,pipelines,elevated piers,wind turbine towers and rocket bodies are very common working mode.As a typical underactuated system,the payload will inevitably sway when the crane accelerates,decelerates and is disturbed by external disturbances,which will greatly affect the working efficiency of the crane and bring potential safety hazards.Therefore,the problems of anti-sway and positioning of the crane has attracted widely attention of researchers.The research of existing cranes is mostly carried out by using the point mass single-pendulum model.However,due to special shape of the slender-beam payload,in the process of vertical lift-up,one end of the payload is lifted and the other end is in contact with the ground,which has complex nonlinear three-dimensional dynamic characteristics.Meanwhile,it also shows obvious double-pendulum dynamic characteristics in the process of transportation.These characteristics make the stability control of slender-beam payload during vertical lift-up and transportation process more complex than point mass payload.Considering the above problems,this thesis studies the vertical lift-up and transporting process of the slender-beam payload as follows:(1)The model establishment and anti-sway control of the lift-up process.Based on the Lagrange method,the nonlinear three-dimensional dynamic model for the vertical lift-up process of the slender-beam payload is established,and the three-dimensional sway dynamic characteristics of slender-beam payload are revealed.On this basis,a nonsingular terminal sliding mode control method is proposed to suppress the sway,and the stability of the controller is proved by Lyapunov method.Simulations and experiments are carried out and the results show that the proposed method can realize the anti-sway control of the vertical lift-up process of the slender-beam payload,and has strong robustness to external disturbances and system parameters change.(2)Anti-sway control method for cranes locating at random position in transportation process.Considering the obvious double-pendulum dynamics in the vertical transportation of the slender-beam payload,and the difficulty of locating the payload in manual operation.Firstly,the double-pendulum dynamic model of the slender-beam payload during vertical transportation process is established,and then a single and double closed-loop compound anti-sway control method is proposed based on PD control.Specifically,the sway angle single closed-loop control is used to suppress the payload sway in the acceleration and uniform speed process of manually controlling the crane.In the process of locating,sway angle and displacement double closed-loop control is adopted to locate the payload at the desired position.On this basis,a bumpless transfer method is proposed,which effectively improves the performance of the controller.Simulation and experimental results verify the effectiveness of the proposed methods.(3)Development of anti-sway industrial control system for vertical lift-up and transportation of the slender-beam payload.Considering the requirements of practical industrial applications.Two anti-sway industrial control system for vertical lift-up and transportation of the slender-beam payload are proposed.Firstly,based on programmable logic controller(PLC),a PLC industrial control system for vertical lift-up and transproting process of slender-beam payload is developed,which includes PLC control algorithm and industrial equipments such as PLC,frequency converter,encoder,inclination sensor,human machine interface(HMI).Further,considering the problems of weak computing power and high cost of PLC,a special embedded system for vertical lift-up and transporting control of the slender-beam payload is developed based on STM32F407ZGT6 microprocessor.The system can receive the measurement signals of the crane speed,displacement sensor and hook inclination sensor,quickly calculate the stable control quantity of the vertical lift-up and transportation processes of the slender-beam payload according to the embedded software algorithm,and communicate with the frequency converter to control the crane movement and suppress the oscillation.Aiming at the vertical lift-up and transportation process of slender-beam payload,this thesis establishes the dynamic models of lift-up and transportation process respectively.On this basis,stability control methods are proposed.Meanwhile,Simulations and experiments are carried out to verify the effectiveness of the proposed methods.Besides,special hardware control systems are designed.Therefore,the research of this thesis has great academic value and engineering practical significance for crane intelligent control.