Research On Tension Control System Of Fiber Placement Machine

Technology of fiber placement is the key point of the process forming thecomposite material, which is widely used in aviation area, especially in manufacturingbig plane. Fiber placement machine is the key equipment of the process, which is thekey support in improving the automation of processing the composite material inaviation industry. Tension control system is an essential part of the fiber placement,which control the tension of the fiber. The value and the amount of fluctuations affectthe quality of the products.This paper establishes a master-slave model tension control system with DSPserving as the control unit and the slave computer, PC serving as the master computer,AC servo motor of Matsushita and low-friction cylinder serving as the execution unit,optical encoder serving as the feedback unit, tension sensor serving as the detection unit.The low-friction cylinder exert the tension to the fiber, the optical encoder senses theswing of the arm and send the signal to the control unit, the AC servo motor working atthe speed-control model maintain the balance of the arm through accelerating orreducing the speed of the fiber. All of the above form the closed-loop system.Firstly, designing the mechanical structure and establishing the mathematicalmodel of the tension control system through analyzing the system. Analyze the error ofthe system under the input signal of control and disturbance with MATLAB. Analyzethe performance of the system adding the PID part under typical input signal.Secondly, design the software and hardware of the control system with DSP anddesign the circuit for the tension control system through the learning of DSP. The circuitmainly includes the essential circuit of DSP, the AD model, the DA model, thecommunication model based on RS232, optical encoder model as well as design thePCB etc. As for the software, with the idea of model-program, program the program ofthe DSP with the abundant Interrupt of the DSP, which improves the flexibility andreadability of the program to a great extent.Lastly, do the experiment on the equipment after establishing the whole system.The results of the experiment show that the system is capable of maintaining the steadyof the tension of the fiber under different velocities and the max value of thefluctuations of the tension is1.8N within the acceptable extent. However, the resultsalso show that there is the dead band of tension and the system is hard to keep thesteady of the tension within the low tension.