Design And Study Of Leveler Control System Based On Fuzzy PID

Green development and intelligent manufacturing are two major themes of the development of iron and steel industry.Leveler is a common equipment in the industrial chain of iron and steel industry as well as an important equipment to ensure the quality of steel plate.It is mainly used to correct various specifications of plates and cut into blocks.Roller leveler is to use the "Baushinger Effect" of materials to bend the plate many times,making a variety of original curvature gradually become a single curvature,and finally leveled it.In this paper,the leveling and shearing unit of a steel logistics distribution center in Shenyang City,Liaoning Province,is reformed and upgraded.The original leveling and shearing machine has the following problems: the leveling accuracy and leveling quality are not stable due to the restriction of steel plate thickness,plate moving speed,environmental temperature and the proficiency of operators;the accuracy of fixed length shearing is not high,which can barely meet the error of two thousandths;the independent control of uncoiling,straightening,fine straightening,shearing,palletizing and other parts,with low automation,affects the work efficiency and Production capacity: there are vibration and noise in the leveling process,especially when the thickness of steel plate is greater than 12 mm,the vibration and noise are more serious.In view of the above problems,this paper mainly completed two aspects of work.On the one hand,the design calculation and simulation analysis of the most important part of the leveler,the leveler roller,solved the problems of unstable leveler accuracy,vibration and noise.On the other hand,based on the touch screen and PLC,the leveler control system is designed and implemented.The original decentralized and independent control is changed to centralized and integrated control,which improves the degree of automation,shortens the working cycle and improves the production efficiency.Because the leveler control system has time-varying,large lag and non-linear factors,the fuzzy PID control algorithm is introduced into the control system designed in this paper,the accuracy of the cut to length is improved obviously,and the error can be controlled within one thousandth.The specific research contents of this paper are as follows: first,the significance of the subject is proposed;the current situation and development trend of leveler at home and abroad are introduced;the current situation and development trend of PID algorithm and fuzzy control algorithm at home and abroad are introduced.Secondly,the production process of the leveler is analyzed,and the structure and parameters of the key components are described.Aiming at the problems of vibration and noise in the leveler,the design calculation and simulation analysis of the leveler roll are carried out under the known conditions of steel plate material,leveler curvature,access strength and bite condition,and the optimal design of the leveler roll is completed.Third,based on the production process of the leveler,the hardware selection is completed,the hardware structure diagram and electrical wiring diagram are designed,the touch screen interface and PLC program flow chart are designed,the I/O address distribution table is drawn,the PLC control program is compiled by Siemens STEP7 software,and the program is debugged and monitored on site.Fourth,the structure of the PID controller and the commonly used discretization method are described,three methods of PID parameter setting and different application occasions are analyzed,the fuzzy control algorithm is studied,the design steps of the fuzzy controller are described in detail,and the design of the fuzzy controller is completed.Fifthly,the fuzzy PID algorithm is introduced to solve the problem of unstable steel coil conveying speed,and the structure and working principle of the fuzzy PID controller are analyzed.The mathematical model is built according to the controlled object,and the transfer function of the leveler control system is obtained.A new fuzzy PID controller is designed,and the fuzzy control rule table is obtained by off-line calculation,which can complete off-line calculation of the work of on-line table checking.The simulation results show that the fuzzy PID controller designed in this paper has the advantages of short dynamic adjustment time,small overshoot,good robustness and better performance.