彈性輸送機系統的階層式控制模式設計與實作

Abstract

本研究提出以階層式控制模式控制彈性輸送機系統的方法。基本上， 一般製造系統的 AMR架構包括四個層次，由上而下依序為：規劃、執行、 控制、製造。階層式控制模式是指將作為控制用途的監控器分配到執行層 與控制層。控制層監控器主要提供順序控制的功能；執行層監控器則用以 協調控制層監控器的運作。在設計方面，這兩個層次的監控器皆經由架構 轉換法來設計。在實作方面，控制層監控器以階梯圖程式實作，執行層監 控器以專家系統法則實作。通常一個複雜的輸送機系統需由數百條位於執 行層的法則來控制，階層式控制的主要好處是將計算的負擔分散於不同的 層次；當然，亦可減少網路傳輸的流量，並提高輸送機系統的可靠度。最 後，本研究採用G2即時型專家系統與Allen-Bradley PLC-5/20E 可程式控 制器，實作出彈性輸送機系統的控制軟體，以證實這個新方法的可行性。 Hierarchical control model is proposed to control flexible conveyorsystem. Basically there are four levels in the popular AMR architecture ofmanufacturing system: planning, execution, control, and manufacturing.Hierarchical control model means to distribute supervisors for controlpurposes at the execution and control levels. The supervisors at the controllevel is essentially dedicated to the functions for sequential control; thesupervisors at the execution level is designed for coordinating the lowerlevel ones. In the design phase, supervisors at both levels are designedthrough hierarchy transformation method. In the implementation phase, thesupervisors at the control level are implemented by ladder diagrams, but thesupervisors at the execution level are rules of expert system. Usually acomplicated conveyor system needs hundreds of rules at the execution level.A major benefit of the new approach is to distribute the computation burdenat different levels. Naturally this reduces the traffic load on the networkand makes the conveyor system more reliable. Also a software system based onreal-time expert system G2 and Allen- Bradley PLC-5/20E has been implementedfor showing the feasibility of this new approach.