Aid to the qualitative design of dynamic systems.

Summary We present in this thesis the Qdes (qualitative design) method of functional design of a dynamic system in the fields of hydromechanics, electronics, automation, chemistry, biology. . This method is applied from the pre-design phase, whereas a design alternative proposed by the designer is only defined by its schematic diagram, making it possible to invalidate as soon as possible entire families of real differential systems. This method is inspired by the work done in qualitative physics. It consists in carrying out a qualitative simulation analysis of the total supply type, and then to judge the degree of adequacy of the result obtained (supply graph between qualitative states) with functional dynamic specifications in terms of the intersection of two graphs. The first point of this work consists in fundamentally revisiting the total provisioning method with the non-causal resolution technique of constraint propagation. A new simulation algorithm is proposed which includes a formal qualitative derivation, a new state enumeration principle which avoids the problem of qualitative chaos, an explicit sorting of states into instants or time intervals which alternate during the determination of transitions. The second part of this thesis proposes a design model based on an original definition of a functional dynamic specification (set of qualitative curves for some variables, which can have approximate values and relative temporal dependencies). New algorithms for intersecting a set of specifications with a supply graph and for managing symbolic times are proposed. Qdes manages a design history in the form of a hierarchy of result graphs allowing to reason at different problem grain sizes (filter and aggregation operators). A design methodology is proposed, a class of specific problems is identified and a comparison is made with other design systems.