A bridge crane advanced control system implemented by means of a distributed expert system

A distributed expert system has been proposed for the bridge crane control. Its configuration is mainly based on the use of distributed nodes connected by means of a CAN network This type of systems allows the implementation of highly flexible control systems capable of adapting themselves to different situations. The expert system used is based on rule nets (RN), which are a formalism that seeks to express an automatism in a similar way to as would make it a human being:"IF antecedents THEN consequents". But at the same time rule nets are a tool for the design, analysis and implementation of rule based systems (RBS), and consist on a mathematic-logical structure which analytically reflects the set of rules that the human expert has designed. Additionally, the RN is able to take decisions concerning possible malfunctions and has bounded response time. In this paper the design of the proposed control system is shown with the methodology is presented. Satisfactory results have been obtained when the control system has been applied in a scale model assembly chain crane, important advantages being shown over previously implemented centralised knowledge-based systems.