PI-observer-based reconstruction of effect-variables and construction of characteristic curves

Usually, the behaviour of control systems is more or less influenced, for example, by effects of nonlinearities, disturbances, couplings and faults. The content of this contribution concerns the reconstruction of those variables representing these effects. The means for reconstruction is the proportional-integral observer, a Luenberger observer with a proportional and an integral feedback of the output reconstruction error. The description of the underlying reconstruction system for this linear observer, its structure and its design is followed by an exemplification with both a linear parameter-dependent model of the track guided city bus and a non-linear model of the friction affected oscillator. Relevant terms are: time-related effect-variable reconstruction, characteristic-curve construction, asymptotic robustness, linear-quadratic design and reconstruction parameters.