高速射出成型機控制器之設計與製作

Design and Implementation of High-Speed Injection Molding Machine Controller

指導教授 : 黃榮堂    研究生 : 許有心  機電整合研究所 88年


摘要

射出機一直是國內產值很大的工具機產業,只可惜在控制器方面較薄弱,亟需往高速、精度良好的高性能控制器方面發展。這也是本論文的終極目的。
傳統使用在射出機上的開迴路控制無法滿足高精度及響應的要求,所以本論文以模糊比例積分(Fuzzy PI)控制器為基礎,因為PI控制器沒有穩態誤差,但其暫態響應較慢為其缺點,所以在改善暫態響應上則加入前饋補償控制(feedforward control)來加快暫態響應,而以壓力微分控制器來消除壓力變化所造成變動,結合這三項特質,使得控制器更具強韌性。
射出機速壓切換控制一直是個問題,本論文以四個參數,包括開始減速的壓力值(PSH)、速壓切換點處的速度允許上限值(VAH)、速度允許下限值(VAL)及有效位置比較區(A)為控制的依據,而其中在速壓切換時需從高速切換到較低速,這項減速函數的決定常易受到負載、塑料與塑化螺桿之間的摩擦,以及切換點設定的影響,本文特別以類神經網路的方式來決定此減速函數。
本論文以Matlab中的Simulink Toolbox來建構所有的控制系統,包括非線性的油壓系統、負載變化、以及控制器等等,做理論上的模擬。在實驗驗證上,則以自行改裝的射出機為實驗載具,最高速度達90mm/sec,在實際射出到模具內的實驗中,射速、速壓切換控制皆得良好的結果,證實本研究所提出的控制方法有實用價值。

關鍵詞:高速控制、模糊控制、前饋控制、速壓切換

ABSTRACT

Injection Molding Machine is the high value industry for toolmachine, but controller is weak. We have to develop the controller for high speed and precision . This is also top target of my research.Using the open loop control method on injection molding machine can not meet the high-precision requirements, so our controller is on the basis of the Fuzzy PI controller in the experiment .Because the Fuzzy PI have no steady state error , but it's transient response is not good .So We can improve transient response by adding feedforward control,and eliminate variation owing to the change of pressure by using the pressure-different controller .The controller is robust with the three characteristics.On the speed to pressure switch control, refer to four parameters including PSH、VAH、VAL and A to control . We need a speed-down function to switch from high speed transfer to lower speed. The speed-down function isn't easy to decide under the influence of load, plastomer , friction and the switch point setting. So the speed-down function is decided with Neural-Network in the research.
In my research ,use the MATLAB/SIMULINK software to establish the control system , including the nonlinear hydraulic system , the change of load pressure and the controller and simulation. We retrofit the injection molding machine to experiment. The maximum speed can reach 90mm/sec.Because we get nicer results in high speed and switch control. So prove our controller have practicability.

Keyword:High-Speed Control、Fuzzy Control、Feedforward Control、Speed to Pressure Switch.