Research On Tension Control System Of Automated Fiber Placement

The improvement of the performance of modern aircraft has put forward higher requirements on the composite materials and their forming processes.As an advanced composite material forming technology,automatic fiber placement technology can achieve the deployment of complex curved surfaces efficiently.Its forming quality has obvious advantages in various forming processes.The tension of the fiber is a very important process parameter for automatic placement and has a direct effect on the forming quality of the final product.Improper tension can result in a variety of deposit defects.Therefore,it’s significant to design a stable,rapid response tension control system.During the automatic laying process,the equipment undergoes frequent acceleration and deceleration processes with a maximum speed of 1m/s and a maximum acceleration of 1.5m/s2.This paper presents a torque-mode closed-loop tension control system,by adding a spring roller buffer device to solve the case of rapid acceleration wire breakage phenomenon.The control system adopts servo motor as the executive component and the tension sensor as the feedback component.First of all,the dynamic model of the mechanical structure of the system without spring rolls was established.The stability of the system was analyzed by MATLAB.Using Simulink to study the response of the system to typical input signals and disturbance signals after adding PID controller.The simulation results show that the system has a 30.5%overshoot when the input signal is a step signal,a 10.4%tension fluctuation when the speed disturbance signal is a ramp signal and a 132.4%tension fluctuation when the speed disturbance signal is a step signal.Then,a dynamic model of the spring roll is established to study its effect on the response speed and peak tension of the control system.The simulation results show that the influence of the spring roll on the control system is related to its own damping and elastic coefficient.Appropriate parameters not only prevent the yarn from breaking,but also improve the dynamic performance of the system.Finally,the principle of spring roll parameter selection is given:1.In the choice of damping,the spring roll with damping between 50N·s/m and 150N·s/m can effectively reduce the peak value of tension under various conditions;2.In the selection of elastic coefficient,the value of damping needs to be considered synthetically:when the damping value is less than 10N·s/m,select 950N/m is more appropriate;when the damping is larger than 10N·s/m,spring elastic coefficient take 320N/m can get better control effect.Finally,build an experimental platform with IPC as the core,and complete the preparation of the control program.On the experimental platform,the effect of the system performance and the spring roll with different elastic modulus on the control effect is verified.The experimental results show that the best control effect is obtained by using 950N/m spring:the tension fluctuation rate under constant speed is less than 4%,the tension fluctuation rate when accelerating at 4.04m/s2 is less than 25%,and the yarn return speed is fast,meet the use of the AFP machine requirements.