| Plastic has become one of the most basic material in our society currnently, which hasinvolved in all the fields of daily life. At Present, about 80 persent of plastic is manufactured byscrew extruding. Plastic extruder is the critical equipment on plastic tube materials product line.The temperature control effect of extruder's stuff container influences the capability and quality ofextrusion products dierctly. Thus the dependability of temperature control over stuff container hasbecome an important part of ectruder molding. In industry process, Temperature of barrel greatlyaffects the productivity and the quality of finished products.The charging barrel temperature of extruder is the main parameter studied in the paper. Theartical includes some aspects as follows. The principle, the merits and drawbacks of the traditionalPID controller are discussed firstly. The control scheme of Fuzzy PID is proposed and a newhighly precisious fuzzy PID controller is designed. Secondly, the components of tempreturecontrol system are analysed. All kinds selectable schemes are compared and the best one isdetermined to be adopted. The article has also studied the the principle of the fuzzy control systembased on PLC, which is used to calculate the numeric value involved in fuzzy PID algorithom.And the programme based on PLC is provided. Last, the monitored control system of extruder isdeveloped. The control interface is designed to set the tempreture of areas and the actualtempreture. The users can not only modify the set point and the relative parameters,but alsoobserve the history data recorded graphically. The real-time curves of the tempreture controlshows effectivity of the fuzzy PID control algorithm in physical system.The experiment results indicate that more excellent control effects for large lag objects areobtained with these methods than with traditional linear PID controller and these cntrollers haveexcellent robust and self-adaptation performance. |
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