A Compositional Approach to Control Software Design of Automation Systems Based on Mechatronic Modularity

Abstract

For many years machine builders and system integrators have been designing control software for systems and machines that are suitable for accomplishing particular tasks and can operate in specific environments. Although these kinds of systems are capable of doing their assigned tasks properly, it is challenging to adopt them to a new task or environment condition in various industrial automation applications. The main reasons for these limitations are the monolithic and non-systematic design approaches used for implementation of such control systems, which are deficient in such capabilities as agility, scalability, handling complexity and reconfigurability. These deficiencies hinder the automation industry’s ability to cope with the increasing expectations of the markets. The intention of this research is to explore the inherent mechatronic modularity of machines and systems as a base for their control software. We propose a methodology for developing component software for mechatronic components, which enhances the concept of Intelligent Mechatronic Components (IMC) on account of better composability. This aims at increased performance of software design and maintenance, as well as systems flexibility and reconfigurability of automated systems. It is demonstrated that the desired behaviour of a certain class of machines can be composed of the behaviours of its mechatronic components, including a fully decentralized scheduling and operation control. This concept aims at the realization of machines that are not bound to performing predefined tasks in particular environments, but rather accept more changes in their configuration, in the tasks and the environment. To this end, it introduces a rule-based approach for automatic configuration of physical mechatronic components, then proposes a uniform architecture for control software design of IMCs. This architecture envisages the machines’ control to be composed of a set of modular software components with a standardized interface. This makes them intuitive and easy to install, to create the desired behaviour for customized automation systems. These systems will fulfil specific tasks with the minimum development time and effort. In this method, mechatronic software components behave similarly to autonomous agents. They operate with the knowledge of their capabilities, tasks and environment, to perform some reasoning and make collective decisions on the fly to achieve the desired goals. The control software encapsulates both high-level and low-level control of an IMC. The IEC 61499 Function Blocks architecture is used as an implementation platform that enables system-level simulation and transparency of deployment. Key features of the proposed approach are: the reusability, compatibility and autonomy of modular software components, which require limited dependence on human intervention. These components cover such aspects of the manufacturing life cycle as process planning, task scheduling, online optimization and failure avoidance. The results of this research will enhance the generation of control and operation of intelligent machines and add design flexibility to automation systems while minimizing their costs and efforts. A number of case studies, whose controls are synthesized using the proposed approach, are chosen as illustrative examples for the proposed methodology.