Journal of Intelligent and Robotic Systems 15: I-2, 1996. 1

Guest Editorial" ROBOT CONTROL

The analysis and improvement of performance in complex systems, the adapta- tion of plants to new demands or conditions and the design of 'optimal' systems are a few of the challenges confronting engineers, systems scientists and ap- plied mathematicians today. In many cases solutions to problems in areas such as these may be found through the use of appropriate mathematical models. The dynamic case, whether continuous time or discrete time, deterministic or stochastic, presents special challenges and derivation of an appropriate solution depends strongly on the proper initial formulation of the goals and constraints. Increasingly this demands an interdisciplinary approach to modelling.

Such a model is intended to help for a better understanding of what is going on in the system and especially to assist in finding a good solution of the problem to be solved.

Models of the kind discussed above can take the form of sets of equations, graphs or nets, or some combination of elements such as these. The derivation, combination, simplification and validation of models and sub-models were the main topics of the IMACS symposium on Mathematical Modelling which was hold in Vienna during February 2-4, 1994.

These general assertions are true also for problems in robotics. And it was interesting to see that during this conference not only 4 special sessions were devoted to such problems but also several more general papers or papers high- lighting modern approaches dealt basically with robotics.

Upon recommendation of the IPC, 7 contributed papers were selected out of 17 contributions in the robotic field (not counting the many papers on mechanical systems modelling closely related to robotics) to 1st MATHMOD Vienna for publication in this special issue of the Journal of Intelligent and Robotic Systems.

It should be mentioned further, that the 3 invited surveys and 21 contributed papers were selected (out of some 190 contributions to I st MATHMOD Vienna) for publication in a special double issue of the IMACS Journal of Mathematics and Computers in Simulation.

These papers deal with the important problem of model validation, various modelling approaches such as iterative design of models, mechanistic modelling, object-oriented modelling of qualitative modelling or demonstrate modelling ap- proaches for typical areas of applications.

Last but not least, the editors wish to express their sincere thanks to all who have assisted them by making the idea of this symposium known within the

2 GUEST EDITORIAL

scientific community, by acting as sponsor, cosponsor or session organizer and who have assisted them in the reviewing process for the conference and for this special issue.

I. Troch, F. Breitenecker