Applied Research On Optimal Control Algorithm For Crane Anti-swing System

Crane is often used for carrying containers and goods in port,and has the great significance for development of manufacturing and transport.Along with the system running,the load would be swing easily and be harmful to efficient works.To reduce the situation that the crane swing when loading and unloading,and to ensure safety in production and improve production efficiency,the method of optimal control was adopted to control the crane anti-swing system.Based on the experimental model of system identification and data collection,expressions were obtained from the relationship between load angle and car speed.Furthermore,the mechanism model was established to analyze mechanical structure of the system,and obtained the relationship between crane system and two-dimensional plane swing nonlinear model of load through Lagrange equation.After that,some necessary assumptions of the actual situation in reality were proposed,and secondary factors and interference problems were ignored,both of them were used to further simplify the dynamic model of the crane anti-swing system,and to obtained the transfer function and state space equation.Finally,the stability,controllability and observability of system were verified through the characteristic analysis of MATLAB.According to the established model,three methods of optimal control were proposed: time optimal control,time-angle optimal control,Bang-Bang control,and each of them was respectively parsed,derived and validated.To eliminate the load swing in the course of the operation of crane system,and to make sure the car accurately arrives at the destination,time optimal control solved the optimum switching-over time of optimal control when car in the stage of startup,uniform motion and braking.By establishing the optimized index and boundary conditions,the optimal speed control curve was obtained through time-angle optimal control.According to the law of conservation and transformation of energy,Bang-Bang control accelerated the speed of the car and built up optimization indexes and constraints,and the angle of the load was controlled effectively.Three control methods were used for multi-groups experiment of Simulink respectively,and the feasibility of the algorithm was verified.Based on the B&R PCC platform of crane system,the hardware configuration and software of the system structure was introduced,and electrical principle was given.Then,thoughts and processes of program designed for Human Machine Interface(HMI)of crane system was analyzed,and operation steps and functional specification of HMI were introduced.Through the C programming of Automation Studio software,three control methods were applied to the crane system platform for multi-groups experiment,including time optimal control,time-angle optimal control and Bang-Bang control.To achieve optimum state,three different optimal anti-swing effects were obtained after adjusting the parameters of control variables.The experimental result shows that these methods can keep angle is within 10 ° in the process ofsystem running,and can make sure the car accurately arrives at the destination with position error within 0.2%.Moreover,when the crane has different goods transport distances,time-angle optimal control and Bang-Bang control can be chosen if the distance is short,otherwise the optimal control and Bang-Bang control can be chosen.