Notes on Recent Achievements in Proving Stability using KeYmaeraX

KeYmaeraX is a Hoare-style theorem prover for hybrid systems. A hybrid system can be seen as an aggregation of both discrete and continuous variables, whose values can change abruptly or continuously, respectively. KeYmaeraX supports only variables having the primitive type bool or real. Due to the mixture of discrete and continuous system elements, one promising application area for KeYmaeraX are closed-loop control systems. A closed-loop control system consists of a plant and a controller. While the plant is basically an aggregation of continuous variables whose values change over time accordingly to physical laws, the controller can be seen as an algorithm formulated in a classical programming language. In this paper, we review some recent extensions of the proof calculus applied by KeYmaeraX that make formal proofs on the stability of dynamic systems more feasible. Based on an example, we first introduce to the topic and prove asymptotic stability of a given system in a hand-written mathematical style. This approach is then compared with a formal encoding of the problem and a formal proof established in KeYmaeraX. We also discuss open problems such as the formalization of asymptotic stability

Experimental Validation of a Dynamic Virtual Power Plant Concept Based on Multiple-Converter Power Hardware-In-the-Loop Test Bench

Recently, the concept of dynamic virtual power plants (DVPP) has been proposed to collectively provide desired dynamic ancillary services such as fast frequency and voltage control by a heterogeneous ensemble of distributed energy resources (DER). This paper presents an experimental validation of a recent DVPP control design approach on a multi-converter power hardware-in-the-loop (PHIL) test bed system. More specifically, we consider a DVPP composed of a wind generation system, a photovoltaic (PV) system, and a STATCOM with small storage capacity to collectively provide grid-following fast frequency regulation in the presence of grid-frequency and load variations. The performance of the aggregated DVPP response is evaluated with respect to its ability to match a desired dynamic behavior while taking practical limitations of the individual DVPP units into account.Comment: 8 Pages, 11 Figures, 22nd Wind & Solar Integration Workshop 202

Proceedings - 31. Workshop Computational Intelligence : Berlin, 25. - 26. November 2021

Dieser Tagungsband enthält die Beiträge des 31. Workshop Computational Intelligence. Die Schwerpunkte sind Methoden, Anwendungen und Tools für Fuzzy-Systeme, Künstliche Neuronale Netze, Evolutionäre Algorithmen und Data-Mining-Verfahren sowie der Methodenvergleich anhand von industriellen und Benchmark-Problemen

Global Versus Local Lyapunov Approach Used in Disturbance Observer-Based Wind Turbine Control

This contribution presents a Lyapunov-based controller and observer design method to achieve an effective design process for more dedicated closed-loop dynamics, i.e., a maximal flexibility in an observer-based controller design with a large consistency in desired and achieved closed-loop system dynamics is intended. The proposed, pragmatic approach enhances the scope for controller and observer design by using local instead of global Lyapunov functions, beneficial for systems with widely spaced pole locations. Within this contribution, the proposed design approach is applied to the complex control design task of wind turbine control. As the mechanical loads that affect the wind turbine components are very sensitive to the closed-loop system dynamic, a maximum flexibility in the control design is necessary for an appropriate wind turbine controller performance. Therefore, the implication of the local Lyapunov approach for an effective control design in the Takagi-Sugeno framework is discussed based on the sensitivity of the closed-loop pole locations and resulting mechanical loads to a variation of the design parameters

Proceedings - 30. Workshop Computational Intelligence : Berlin, 26. - 27. November 2020

Dieser Tagungsband enthält die Beiträge des 30. Workshops Computational Intelligence. Die Schwerpunkte sind Methoden, Anwendungen und Tools für Fuzzy-Systeme, Künstliche Neuronale Netze, Evolutionäre Algorithmen und Data-Mining-Verfahren sowie der Methodenvergleich anhand von industriellen und Benchmark-Problemen

Proceedings - 32. Workshop Computational Intelligence: Berlin, 1. - 2. Dezember 2022

Dieser Tagungsband enthält die Beiträge des 32. Workshops „Computational Intelligence“ des Fachausschusses 5.14 der VDI/VDE-Gesellschaft für Mess- und Automatisierungstechnik (GMA) der vom 1.12. – 2.12.2022 in Berlin stattfand. Die Schwerpunkte sind Methoden, Anwendungen und Tools für - Fuzzy-Systeme - Deep Learning - Machine Learning sowie der Methodenvergleich anhand von industriellen und Benchmark-Problemen

Замечания о последних достижениях в доказательстве устойчивости с использованием KeYmaeraX

KeYmaeraX is a Hoare-style theorem prover for hybrid systems. A hybrid system can be seen as an aggregation of both discrete and continuous variables, whose values can change abruptly or continuously, respectively. KeYmaeraX supports only variables having the primitive type bool or real. Due to the mixture of discrete and continuous system elements, one promising application area for KeYmaeraX are closed-loop control systems. A closed-loop control system consists of a plant and a controller. While the plant is basically an aggregation of continuous variables whose values change over time accordingly to physical laws, the controller can be seen as an algorithm formulated in a classical programming language. In this paper, we review some recent extensions of the proof calculus applied by KeYmaeraX that make formal proofs on the stability of dynamic systems more feasible. Based on an example, we first introduce to the topic and prove asymptotic stability of a given system in a hand-written mathematical style. This approach is then compared with a formal encoding of the problem and a formal proof established in KeYmaeraX. We also discuss open problems such as the formalization of asymptotic stability.KeYmaeraX -- это доказательство теорем в стиле Хоара для гибридных систем. Гибридную систему можно рассматривать как совокупность дискретных, так и непрерывных переменных, значения которых могут изменяться резко или непрерывно соответственно. KeYmaeraX поддерживает только переменные, имеющие примитивный тип bool или real. Благодаря сочетанию дискретных и непрерывных элементов системы, одной из перспективных областей применения KeYmaeraX являются системы управления с замкнутым контуром. Система управления с замкнутым контуром состоит из установки и контроллера. В то время как установка в основном представляет собой совокупность непрерывных переменных, значения которых меняются со временем в соответствии с физическими законами, контроллер можно рассматривать как алгоритм, сформулированный на классическом языке программирования. В этой статье мы рассмотрим некоторые недавние расширения исчисления доказательств, применяемые KeY\\-maeraX, которые делают формальные доказательства устойчивости динамических систем более выполнимыми. Основываясь на примере, мы сначала познакомимся с темой и докажем асимптотическую устойчивость данной системы

Anwendungen von Glyphosat im deutschen Ackerbau – Betriebliche Aspekte

Glyphosat ist der in Deutschland am häufigsten eingesetzte herbizide Wirkstoff. Trotz eines hohen Stellenwertes in verschiedenen ackerbaulichen Situationen ist die agronomische Bedeutung des Wirkstoffes im Nicht-GVO-Ackerbau nach wie vor wenig erforscht. Aufgrund dessen ist im Winter 2014/2015 eine umfangreiche Erhebung unter konventionell wirtschaftenden landwirtschaftlichen Betrieben durchgeführt worden. Auf Basis der Umfrageergebnisse konnte mithilfe einer Cluster-Analyse ermittelt werden, wie sich Betriebstypen hinsichtlich der Glyphosatanwendungen unterscheiden. Eine Veranschaulichung von sieben verschiedenen Clustern erlaubt einen differenzierten Einblick in ackerbauliche Betriebsstrukturen. Die Betriebstypen unterscheiden sich vor allem bezüglich der Wahl zwischen konservierender und wendender Bodenbearbeitung. Analog zu dieser Differenzierung gestaltet sich auch die Intensität der Glyphosatanwendungen. Zusätzlich wird sichtbar, dass sich Cluster mit einem höheren Glyphosat-Anwendungsumfang durch einen geringeren Arbeitskräftebesatz, mehr Ackerfläche und/oder einem verstärkten Zwischenfruchtanbau charakterisieren lassen. Des Weiteren geben Betriebsgruppen mit einem intensiveren Glyphosateinsatz eher an, diesen Wirkstoff zum Resistenzmanagement zu benötigen. Die Einschätzungen der befragten Landwirte bezüglich der betriebswirtschaftlichen Bedeutung von Glyphosat variieren je nach Betriebstyp. Mithilfe der Betriebscluster können die wichtigsten Anwendungssituationen von Glyphosatherbiziden im Ackerbau weiter betriebswirtschaftlich analysiert und Szenarien für Folgenabschätzungen gebildet werden.Uses of glyphosate in German arable farming – operational aspectsGlyphosate is the most frequently used herbicide active ingredient in Germany. Studies regarding its usage in non-GMO arable farming are still rare even though it plays an important role in several agronomic situations. Therefore, we conducted a comprehensive survey, which was carried out among conventional German farms in Winter 2014/2015. Based on the results of this survey we analyzed via cluster analysis how types of farms differ in terms of glyphosate usage. An illustration of seven clusters allows deep insights into arable farm structures. The farm types can be distinguished regarding their tillage system and similar to this differentiation also concerning their intensity of glyphosate application. Furthermore, it becomes obvious that farm clusters with a higher level of glyphosate usage are characterized by a lower number of labourers per hectare, more arable land and/or enhanced cover cropping. Moreover, groups of farmers who rely more on glyphosate are more likely to state that they need glyphosate for herbicide resistance management. Farmers’ assessments of the economic importance of glyphosate usage vary depending on the type of farm. By means of the farm clusters, the most important situations of glyphosate usage can be further analyzed economically and scenarios for impact assessments can be made