Martin Horn

RTD Modeling of a Continuous Dry Granulation Process for Process Control and Materials Diversion

Disturbance propagation during continuous manufacturing processes can be predicted by evaluating the residence time distribution (RTD) of the specific unit operations. In this work, a dry granulation process was modelled and four scenarios of feeding events were simulated. We performed characterization of the feeders and developed RTD models for the blender and the roller compactor based on impulse-response measurements via color tracers. Out-of-specification material was defined based on the active pharmaceutical ingredient (API) concentration. We calculated the amount of waste material at various diversion points, considering four feeder-related process-upset scenarios and formulated considerations for the development of a control concept. The developed RTD models allow material tracking of materials that may be used for following the spread contaminants within the process and for batch definition. The results show that RTD modeling is a valuable tool for process development and design, as well as for process monitoring and material tracking.

Stability proof for a well-established super-twisting parameter setting

Abstract Several sufficient stability conditions exist for the super-twisting algorithm. For its tuning in practical applications, however, a popular parameter set is regularly used, which is provided in literature without any stability proof. This short note provides a novel, simple sufficient stability condition which includes this very popular parameter setting.

Energy Efficient Driving in Dynamic Environment: Considering Other Traffic Participants and Overtaking Possibility

This chapter studies energy efficient driving of (semi)autonomous electric vehicles operating in a dynamic environment with other traffic participants on a unidirectional, multi-lane road. This scenario is considered to be a so called hard problem, as constraints imposed are varying in time and space. Neglecting the constraints imposed from the surrounding traffic, the generation of an energy optimal speed trajectory may lead to bad results, with the risk of low driver acceptance when applied in a real driving environment. An existing approach satisfies constraints from surrounding traffic by modifying an existing unconstrained trajectory. In contrast to this, the proposed approach incorporates a leading vehicle’s motion as constraint in order to generate a new optimal speed trajectory in a global optimal sense. First simulation results show that energy optimal driving considering other vehicle participants is important. Even in simple setups significantly (8%) less energy is consumed at only 1.3% travelling time prolongation compared to the best constant speed driving strategy. Additionally, the proposed driving strategy is using 4.5% less energy and leads to 1.6% shorter travelling time compared to the existing overtaking approach. Using simulation studies, the proposed energy optimal driving strategy is analyzed in different scenarios.

Sliding Mode Based Platooning With Non-Zero Initial Spacing Errors

This letter presents a novel approach to unidirectional formation control of multiple vehicles with non-zero initial spacing errors. It is based on concepts of first-order sliding mode control. A combination of two adaptive sliding surfaces enables collision-free platooning with asymptotic convergence to constant distance spacings. It is an attractive feature of the proposed algorithm that only position and velocity of the preceding vehicle are used so that no car-to-car communication is necessary.

Indirect Adaptive Sliding-Mode Control Using the Certainty-Equivalence Principle

A fundamental asset of sliding-mode control is their robustness against unstructured uncertainties. For a successful controller design very little information about the nature of the uncertainty is required. However, in practical control problems often some information about the uncertainty is available. In this case, indirect adaptive control methods may exploit the available information about the uncertainty structure, resulting in powerful adaptation schemes. In this contribution we present a design method that combines these two control concepts. The link is given by the certainty-equivalence approach that relies on the availability of a Lyapunov function for the stabilizing control law. We analyze how various choices of Lyapunov functions impact on our proposed design method. To this end, we briefly review classes of uncertainties that may be handled by various sliding-mode design algorithms. An example serves to illustrate that the violation of these assumptions may yield an unstable closed loop system. We provide an experimental case study that demonstrates the efficiency of the proposed control concept when compared with the conventional super-twisting algorithm.

Recursive FIR-Filter design for fault-tolerant real-time co-simulation

The coupling of real-time and non-real-time systems is directly related to different types of faults which require adequate handling. These faults, such as communication time-delays, data-loss or noisy measurements, originate from the incorporation of real hardware (real-time system) and lead to significant challenges in the coupling process. Without compensating their destabilizing effects the simulation results are corrupted. Ignoring those effects can even result in unstable closed-loop systems in the worst case, which may in turn result in hardware damage. This work proposes a recursive FIR-filter design approach which compensates such fault effects. The effectiveness of the proposed coupling filters is demonstrated by a representative example.

Model Predictive Temperature Control of a Distribution System for Chemicals

In semiconductor manufacturing tight temperature control of chemicals is crucial for meeting clean application requirements. The use of multiple chemistries as well as various configuration options makes precise temperature control a challenging task. In this paper a generic solution for the temperature control in a single wafer manufacturing machinery for wet-chemical processing based on a model predictive control technique is presented. The developed control strategy is implemented and evaluated on a real world unit with realistic wafer cleaning recipes.

Ein Modalmaß für Beobachtbarkeit und perspektivische Beobachtbarkeit linearer zeitinvarianter Systeme

Zusammenfassung Das Modalmaß nach Litz stellt eine einfache Möglichkeit zur quantitativen Bewertung der Beobachtbarkeit eines Systems dar. Einen durch mehrfache Eigenwerte verursachten Beobachtbarkeitsverlust zeigt es jedoch mitunter nicht korrekt an. Vorliegender Beitrag schlägt eine Erweiterung vor, welche dieses Problem behebt. Im Weiteren wird gezeigt, dass sich das modifizierte Maß leicht auf die perspektivische Beobachtbarkeit erweitern lässt. Die praktische Anwendbarkeit des erweiterten Maßes wird anhand eines anschaulichen Beispiels demonstriert.

RegIS – Ein interaktives Informationssystem für Regelungstechnik (RegIS – An Interactive Multimedia Information System for Control Theory)

Abstract Der Einsatz von elektronischen Informations- und Kommunikationstechnologien soll die Qualität und die Effizienz der akademischen Lehre steigern. Das regelungstechnische Informationssystem RegIS ist kein eigenständiges eLearning-System, sondern eine wachsende Sammlung von multimedialen Dokumenten zur Regelungstechnik. Der Einsatz des angebotenen Materials steigert die Attraktivität bewährter Vorlesungen und gibt Studierenden die Möglichkeit, sich im Selbststudium mit der oft als schwierig empfundenen Materie zu beschäftigen. Der Beitrag gibt einen Überblick über den Entwicklungsstand von RegIS und über Erfahrungen beim praktischen Einsatz.