Numerical integration of ODEs in real time systems like state observers: Stability aspects

This paper deals with the performance of some numerical integration methods for Ordinary Differential Equations in real time applications involving stiffness. After summarising the main results about accuracy and stability of some well known schemes, the point of view of the control is emphasized, by showing the impact of the numerical integration on the dynamics of the discretized model. Moreover some peculiarities of the numerical integration in hybrid systems are touched by introducing a simple hybrid model for testing the performances of some numerical integration schemes. Finally some experimental tests are shown, dealing with a control of a sensorless drive whose model is characterised by stiffness.