On the control of dynamic systems with unknown operating point

Bazanella, Alexandre Sanfelice; Kokotović, P.V.; Silva, Aguinaldo S. e

doi:10.1080/002071700219443

Cited by 24 publications

(4 citation statements)

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“…) is different from the original papers [1,19,43], simplifying the proof of the precise criterion for controllability with washout filters considerably [7,19]. It also separates the problem of controllability from the problem of finding the control gains, which can then be designed using standard linear feedback control theory.…”

Section: Lemma 31 (Linear Controllability For Washout Filters)mentioning

confidence: 96%

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Continuation with Non-invasive Control Schemes: Revealing Unstable States in a Pedestrian Evacuation Scenario

Panagiotopoulos¹,

Starke²,

Sieber³

et al. 2022

Preprint

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This paper presents a framework to perform bifurcation analysis in laboratory experiments or simulations. We employ control-based continuation to study the dynamics of a macroscopic variable of a microscopically defined model, exploring the potential viability of the underlying feedback control techniques in an experiment. In contrast to previous experimental studies that used iterative root-finding methods on the feedback control targets, we propose a feedback control law that is inherently non-invasive. That is, the control discovers the location of equilibria and stabilizes them simultaneously. We call the proposed control zero-in-equilibrium feedback control and we prove that it is able to stabilize branches of equilibria, except at singularities of codimension n + 1, where n is the number of state space dimensions the feedback can depend on.We apply the method to a simulated evacuation scenario were pedestrians have to reach an exit after maneuvering left or right around an obstacle. The scenario shows a hysteresis phenomenon with bistability and tipping between two possible steady pedestrian flows in microscopic simulations. We demonstrate for the evacuation scenario that the proposed control law is able to uniformly discover and stabilize steady flows along the entire branch, including points where other non-invasive approaches to feedback control become singular.

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Section: Lemma 31 (Linear Controllability For Washout Filters)mentioning

confidence: 96%

“…The PI control in (2.1) is degenerate, as the right-hand side for ẋwo depends on x only through u. This simplifies the proof of the stabilization criterion compared to the original sources [7,19] and reduces the design of the feedback gains (K st , K wo ) to a standard linear control design problem (see Lemma 3.1).…”

Section: Non-technical Overviewmentioning

confidence: 99%

Continuation with Non-invasive Control Schemes: Revealing Unstable States in a Pedestrian Evacuation Scenario

Panagiotopoulos¹,

Starke²,

Sieber³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Having a zero at the origin, this type of controller, called a washout filter/ controller, [37][38][39][40] is usually used in series with the plant to attenuate sensor drift and flicker noise, which are the dominant lowfrequency spurious signals for electrothermal sensors. 15,32 To simplify the stability analysis of the inner loop, we first approximate the plant dynamics for the X-axis by a simple harmonic oscillator as…”

Section: Controller Designmentioning

confidence: 99%

High-stroke silicon-on-insulator MEMS nanopositioner: Control design for non-raster scan atomic force microscopy

Maroufi

Fowler

Bazaei

et al. 2015

Review of Scientific Instruments

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A 2-degree of freedom microelectromechanical systems nanopositioner designed for on-chip atomic force microscopy (AFM) is presented. The device is fabricated using a silicon-on-insulator-based process and is designed as a parallel kinematic mechanism. It contains a central scan table and two sets of electrostatic comb actuators along each orthogonal axis, which provides displacement ranges greater than ±10 μm. The first in-plane resonance modes are located at 1274 Hz and 1286 Hz for the X and Y axes, respectively. To measure lateral displacements of the stage, electrothermal position sensors are incorporated in the design. To facilitate high-speed scans, the highly resonant dynamics of the system are controlled using damping loops in conjunction with internal model controllers that enable accurate tracking of fast sinusoidal set-points. To cancel the effect of sensor drift on controlled displacements, washout controllers are used in the damping loops. The feedback controlled nanopositioner is successfully used to perform several AFM scans in contact mode via a Lissajous scan method with a large scan area of 20 μm × 20 μm. The maximum scan rate demonstrated is 1 kHz.

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“…(Theorem 3.2) • In order to make some substantial headway under the burden of the above instability results, we shift our attention to adaptive control generalizations of the celebrated Washout filters-traditionally used for stabilizing the Dutch-roll motion of an aircraft during a flight [HLA04,GR97]. Inspired by this framework, we propose the modified KPV-GDA 2 which consists of a tandem combination of GDA together with stabilizing feedback introduces by [BKS97].…”

Section: Introductionmentioning

confidence: 99%

Teamwork makes von Neumann work: Min-Max Optimization in Two-Team Zero-Sum Games

Fivos¹,

Panageas²,

Vlatakis-Gkaragkounis³

2021

Preprint

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Motivated by recent advances in both theoretical and applied aspects of multiplayer games, spanning from e-sports to multi-agent generative adversarial networks, we focus on min-max optimization in team zero-sum games. In this class of games, players are split into two teams with payoffs equal within the same team and of opposite sign across the opponent team. Unlike the textbook two-player zero-sum games, finding a Nash equilibrium in our class can be shown to be CLS-hard, i.e., it is unlikely to have a polynomial-time algorithm for computing Nash equilibria. Moreover, in this generalized framework, we establish that even asymptotic last iterate or time average convergence to a Nash Equilibrium is not possible using Gradient Descent Ascent (GDA), its optimistic variant, and extra gradient. Specifically, we present a family of team games whose induced utility is non multi-linear with non attractive per-se mixed Nash Equilibria, as strict saddle points of the underlying optimization landscape. Leveraging techniques from control theory, we complement these negative results by designing a modified GDA that converges locally to Nash equilibria. Finally, we discuss connections of our framework with AI architectures with team competition structures like multi-agent generative adversarial networks.

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On the control of dynamic systems with unknown operating point

Cited by 24 publications

References 0 publications

Continuation with Non-invasive Control Schemes: Revealing Unstable States in a Pedestrian Evacuation Scenario

Continuation with Non-invasive Control Schemes: Revealing Unstable States in a Pedestrian Evacuation Scenario

High-stroke silicon-on-insulator MEMS nanopositioner: Control design for non-raster scan atomic force microscopy

Teamwork makes von Neumann work: Min-Max Optimization in Two-Team Zero-Sum Games

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