Stefan Krebs

Interval observer for LPV systems based on time-variant transformations

Interval observers are emerging methods for the state estimation of dynamical systems, especially if guaranteed error bounds are of interest as in the case of safety-critical systems. One class of systems that is of particular interest for real applications are LPV systems but so far, only a few approaches for interval observers for LPV systems have been proposed. In this paper, we extend the class of LPV systems for which interval observers can be designed under real operating conditions. We propose an interval observer that is based on a particular time-variant change of coordinates. The behavior of the presented interval approach is shown by numerical simulations of an induction machine.

Coupled boundary interval observer for LPV systems subject to uncertainties in input, output and parameters

Abstract The topic of this publication is the design of interval observers for LPV systems under consideration of parameter, input and output uncertainties that are described by bounded intervals. In the course of the design, also time-varying bounds of the parameter intervals are considered representing the case when parameters are measured with an unknown but bounded measurement error. In this case, an existing approach is extended to handle these parameter uncertainties. The effectiveness of the approach is demonstrated by two numerical examples.

Interval state observer based on a time-variant transformation for LPV systems and application to induction machines

For the state estimation of safety-critical systems, interval observers are an emerging alternative to classical state estimation methods due to their provision of guaranteed information on unmeasurable quantities. One possible application of interval observers are induction machines used as a traction drive whose common models belong to the class of linear parameter-varying (LPV) systems. To overcome the design conditions of existing interval observers for LPV systems, which are too strict for an application to the aforementioned system, we propose a new interval observer design based on a time-variant transformation. The effectiveness of the method is shown by experimental results of an induction machine.

A new modelling and identification approach for guaranteed inclusion of a voltage source inverter's output voltages

During the modelling of technical systems, the developer of the model is always faced with uncertain quantities due to non-ideal measurement devices. In contrast to classical stochastical approaches to handle these uncertainties, guaranteed approaches represent an emerging alternative. They allow on the one hand a direct application of the usually given error bounds of measurements and on the other hand a provision of guarantees regarding a models output. One interesting application area of such methods are safety-critical systems such as electrical traction drives. In this paper, a new methodology to model a voltage source inverter considering unknown but bounded measurement uncertainties during the identification and the operation is presented. The provision of output intervals including the real output voltages is proven by simulations and experiments.

A Cooperative and Competitive Workshop in Mechatronics Engineering

This paper presents a new mechatronics laboratory for students in the 5th semester of the mechatronics degree course at the Karlsruhe Institute of Technology. It is the aim of this teaching event to sharpen the appreciation of synergy effects in the development of mechatronic systems among the students. Despite of the great freedom in the development process, a concept has been evolved, which causes low running costs due to the combination of a model kit with rapid prototyping methods. A first pilot study of the laboratory starting in the winter term 2014 has shown that the students approach the task despite of the high level of difficulty with fun and dedication, especially because of the wide solution space which was unknown for them from previous lectures.