OODB Support for Real-Time Open-Architecture Controllers

Abstract

Open-architecture machine tool controllers have been an important research subject in both academia and industry. They are hard realtime applications that require a built-in database management system to support concurrent data access and provide well-defined interfaces. These advanced applications often utilize object-oriented models to handle complex data types. Since there exists no agreed-upon real-time object model, we design a conceptual real-time object-oriented data model, called ROMPP (Real-time Object Model with Performance Polymorphism). It captures the key characteristics of realtime control applications, namely, timing constraints and performance polymorphism. It uses specialization dimensions to model timing specifications and letter class hierarchies to capture performance polymorphism. Based on the model, we develop a prototype controller on our open-architecture machine tool controller testbed. The controller has been successfully used for a 6-axis robotic table.