Issues of model accuracy and external validation for control system design

Abstract

Model validation is an important but often neglected aspect of the engineering design process. In the control systems field the accuracy of mathematical models which represent the dynamics of the system being controlled can be of critical importance for design applications in which the overall performance specifications are demanding in terms both of accuracy and speed of response over a wide range of operating conditions. In the past many published reports of engineering design projects which have depended in some way upon complex mathematical or computer models have failed to address questions of model accuracy or to include discussion of the processes used to investigate model limitations. Important exceptions can be found in certain safety-critical areas such as aircraft flight control system design. This paper reviews some of the issues that can arise in the validation of models used for engineering design and makes a number of recommendations both about the processes which should be used in the development and application of mathematical models for engineering design and about the education and training of future engineers.