CoDES: a knowledge base for controller design with an expert system

The authors describe the development of a knowledge base for CoDES, an expert system for CAD of controllers. Classical control theory is structured in a form suitable for expert system use, and approximate models are used as part of the rule generation and reasoning. Robust control theory is used to handle the consequences for the modeling error in approximate reasoning and to supervise the validity of the rules. An interactive multiobjective design process with full graphical support is achieved. CoDES is based on a special-purpose shell that provides an interface to MATLAB for computational functions. The rule base is structured as a hierarchy of frames, and the procedural knowledge is stored separately in the form of function files