Study On The Control System Of Let-off And Filling Insertion On Air-jet Loom

Along with the development of microelectronic technology and computer technology,the textile machinery is rapidly pushed forward and it gradually realizes electronization and intellectualizationt in the last decade.As a kind of important weaving equipment in textile machine,Air-jet loom’s technical progress is more impetuous.Besides Continuous attention to high speed,the high-grade air-jet loom joins more expert system and lower operating difficulty. The let-off & filling insertion mechanisms have changed from complex mechanism driving system to electricity driving system.Both motions affect loom rotate speed and efficiency directly.This paper has a system of its own.It designs a kind of air-jet loom master control system which has intelligent let-off and filling insertion to decrease warp vibration frequency and weft flight fluctuation.The key technical points of this paper lie in twice let-off method and fuzzy control filling method.At first,this paper introduces the general scheme design of air-jet loom master control system. The design work includes three parts:the selection of hardware,the design of interrupt board and the design of software.Based on the prototype machine of ZA209i,this paper plans to corresponding electric actuator.Hardware system adopts IPC+slave-computer model,and it designs interrupt board;software design adopts the interrupt control mode.Main program in host computer is divided to multitask modules and written by VC++.Slave-computer adopts embedded mcu system and software is written with assembly language to meet the needs of the real-time calculation in the control process.In the research of let-off system,this paper focuses on the warp vibration.The friction that caused by warp vibration may destroy size film and debase warp strength,even induces warp broken.This paper establishs yam force equation.The boundary curve of warp vibration is obtained between stable region and unstale region with nonlinear vibration analytical method.And it also analyses the effect of each parameters on the warp vibration by numerical method.And then it points out that the effective method of reduce warp vibration frequency is to reduce the warp tension unevenness,so as to educe the twice let-off control method.In the design of let-off system,this paper designs open loop identification method in stop condition.It adopts system identification method to obtain let-off mechanism model.It adopts difference tuning methods of PID parameters and the results show that the numerical optimization algorithm to seek out PI control parameters has good robust.Introducing variable of roll diameter compensation,it designs the adjustment let-off speed method to eliminate the long fragment tension unevenness.In the research of filling insertion system,this paper focuses on the discussion of gas state parameters in main nozzle.It deduces weft force formula in main nozzle and points out that structure of main nozzle and working accuracy are important to pull force.The decrease in diameter of main nozzle can reduce energy consumption.The increase in length of thread tube can increase pull force.Due to the high speed trend of air-jet loom,it is the main development of main nozzle to lengthen thread tube or series nozzles.In the design of filling insertion system,this paper adopts weft tension controller to forecast weft arrival time.The arrival time unevenness of short fragment can be adjusted by adjusting working time of tension controller.The modificative weft arrival time is obtained by weighting the forecast time and measured time.This paper adopes fuzzy control method to adjust long fragment arrival time unevenness.It takes the error between modificative weft arrival time and goal time as controlled variable.Finally,this paper introduces the connection method between DH-AJC and ZA209i,and the controller is fixed on ZA209i air-jet loom.The measured datas are satisfying in follow parameters: long/short term tension irregularity,weft arriving time and peak value of weft tension.It proves this controller is effective.