Research On Temperature And Tension Control Technology Of Automated Fiber Placement

AFP(Automated Fibre Placement) is one of the key point of the advanced composites low-costmanufacturing technology.To make sure the laying quality and high efficiency,the laying parametersneed to be controlled accurately during the AFP progress of uni-directional carbon fiberprepreg.Therefore,the research on controlment of based thermodynamics and tension parameters onautomated fiber placement was carried out in this paper,and the relevant control scheme was presentedaimed at the accuracy control of thermodynamics and tesion parameters as well as their application inengineering.Firstly,the control scheme of stickiness based on AFP was presented-infrared heating systembased on AFP.To make sure the laying temperature of prepreg is always in the optimum layingwindow,the system is able to change the stickiness of prepreg by adjusting the layingtemperature,which can realize the dynamic matching between laying speed and the emissive power ofheating lamp;the heat transfer process between the heating lamp and the laying surface was analyzedand the control equation of dynamic temperature was derived,besides,the matching relation betweenthe laying speed and the heating efficiency was founded;based on the hardware structure of the AFPmachine,the infrared heating system which is based on the variate of laying speed,the controlledquantity of the prepreg surface temperature and the control unit of PLC,was set up.Secondly,a tension control scheme of narrow prepreg was presented-the variable arguments PIDtension control system which based on the motion mechanism of servo motor and air cylinder,and thespeed mode of servo motor.After the analyzation of the tension control characteristic of AFP,thetension require of the AFP machine to the tension system which should realize the small tension ofnarrow prepreg and the rapid response;choose the speed control mode of servo motor and controlmethod of linked swing roller,the close-cycle control made up of tilt angle detection and the servomotor speed;to realize a stead tension control of high speed laying, a integral-separate PID controlmethod was presented.The experimental result indicate that theoretical derivation of dynamic temperature controlequation is suitable to the practical situation;the infrared heating system mentioned before can greatlyimprove laying quality of AFP,and it also can realize the valid cementation between layer and mouldas well as layer and layer.After heating by the infrared,the layer surface is smooth and has no bowannd twist,the plying-up between layers is thick.Further detection indicates that heating has litter influence on the performances of prepreg,and has no effect on forming workpiece.The tension controlsystem based on AFP is able to satisfy the tension demond of low speed,middle speed and high speedsituation during the AFP process.Tension detection found that the tension of under-controlled narrowprepreg is small and response rapidly,and there was no roller-jump phenomenon during theexperiment;the tension control systerm can be used to set up the independent yarn chest of AFPmachine.