Users´ requirements specification for control: an object-oriented approach

The users´ requirements specifications is used for the development of control systems. After considerations about the qualities that such a specification must have, the principles of a method to guide the requirements expression are presented. The approach is organized in a hierarchy which is based on levels of abstraction. Each entity is modeled by an object which is specified and then decomposed in accordance with principles which are oriented to the expression of needs. Principles are defined to favor the external specification of behavioral requirements which are formalized with statecharts. An example of the application of the approach is given