Modelling, design and implementation of machining centers control functions with object-oriented techniques

The paper presents a real application of object-oriented modelling techniques to the design and implementation of low-level, real-time logic control functions of complex machining centers. In particular, a suitable methodology is conceived, based on two different models: the control model structured in a modular hierarchical architecture, which is obtained starting from another model, the plant model. The logic structure of the control model is represented using the Petri nets formalism . In the described work, an object-oriented language has been used for the experimental implementation of the PLC and CNC control functions. Instead of proprietary HW and SW solutions, a "standard" PC has been chosen as controller, equipped with the RTAI Linux operating system, and the open source, object-oriented concurrent language Python. The aim of the work is to prove in real industrial, non trivial, applications the effectiveness of the adoption of object-oriented modelling techniques for the modelling and implementation and, above all, of reconfigurability and reuse, related to real-time logic control functions of machining centers.