This paper aims at describing some original works relating to the formalization of ergonomic knowledge in the field of process control. For this purpose, explicit or implicit concepts, advice and methods issued from Ergonomics, Cognitive Psychology and Human Automation have been taken into account. The medium and long-term objective is to develop engineering tools using ergonomic knowledge base. The concepts and principles used by three rule-based approaches for the "intelligent" ergonomic evaluation, design and management of man-machine interface illustrate this paper.