A decentralized stability criterion for two-level systems with optimization in the feedback loop

2005 ◽  
Author(s):  
P.P. Groumpos ◽  
A.V. Pagalos ◽  
G.S. Stavropoulos
Keyword(s):  
Stability Criterion ◽  
Feedback Loop ◽  
Two Level Systems

scholarly journals Research on Instability Boundaries of Control Force for Trajectory Correction Projectiles

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Rupeng Li ◽  
Dongguang Li ◽  
Jieru Fan
Keyword(s):  
Coordinate System ◽  
Numerical Simulations ◽  
Stability Criterion ◽  
Feedback Loop ◽  
Control Force ◽  
Relevant Research ◽  
Force Magnitude ◽  
Roll Rate ◽  
Novel Method ◽  
Trajectory Correction

The balance of stability and maneuverability is the foundation of the trajectory correction projectile. For the terminal correction projectile without an attitude feedback loop, a larger control force is expected which may cause an instability. This paper proposes a novel method to derive instability boundaries for the control force magnitude. No additional coordinate system is needed in this method. By introducing the concept of angular compensation matrix, the exterior ballistic linearized equations considering control force are established. The necessary prerequisite for a stable flight under control is given by the Routh stability criterion. The instability boundaries for the control force magnitude are derived. The results of example flights are 13.5% more accurate compared with that in relevant research. Numerical simulations demonstrate that if the control force magnitude lies in the unstable scope derived in this paper, the projectile loses its stability. Furthermore, the effects of the projectile pitch, velocity, and roll rate on flight stability during correction are investigated using the proposed instability boundaries.

Dynamic Stability of Mechanical Structures Containing Externally Pressurized Gas-Lubricated Thrust Bearings

1988 ◽  
Vol 110 (2) ◽  
pp. 271-278 ◽  
Author(s):  
P. Plessers ◽  
R. Snoeys
Keyword(s):  
Frequency Response ◽  
Stability Criterion ◽  
Feedback Loop ◽  
Response Functions ◽  
Thrust Bearings ◽  
Supporting Structure ◽  
Nyquist Criterion ◽  
The Stability ◽  
Stability Limits ◽  
Gas Bearing

A stability criterion is presented to evaluate instability phenomena in mechanical systems containing externally pressurized gas bearings. For this criterion, the gas bearing films and the supporting structure are characterized separately by means of frequency response functions. The overall system may be considered as a feedback-loop for which the Nyquist criterion will define stability limits. The analysis demonstrates the interaction between the dynamics of the supporting structure and the air gap. The stability criterion is generalized for systems containing more than one gas film. The stability criterion is verified experimentally.

Stability Criterion of Linear Control Systems with Time Delay

1970 ◽  
Vol 3 (3) ◽  
pp. 86-87 ◽  
Author(s):  
F. L. N-Nagy ◽  
M. N. Al-Tikriti
Keyword(s):  
Control System ◽  
Time Delay ◽  
Control Systems ◽  
Stability Criterion ◽  
Feedback Loop ◽  
Linear Control ◽  
Linear Control Systems ◽  
Loop Gain ◽  
Nyquist Stability ◽  
The Stability

The paper outlines the Nyquist stability criterion linear control systems with time delay, using frequency response results. The variation of the loop-gain and time delay are investigated when the time delay occurs in the forward-loop or the feedback-loop or both. The stability condition of a simple control system is used to illustrate the method.

Novel players fine-tune plant trade-offs

2015 ◽  
Vol 58 ◽  
pp. 83-100 ◽  
Author(s):  
Selena Gimenez-Ibanez ◽  
Marta Boter ◽  
Roberto Solano
Keyword(s):  
Ubiquitin Ligase ◽  
Feedback Loop ◽  
Molecular Level ◽  
26S Proteasome ◽  
Signalling Molecules ◽  
Transcriptional Reprogramming ◽  
Trade Offs ◽  
Jaz Proteins ◽  
Regulatory Feedback Loop ◽  
Fine Tune

Jasmonates (JAs) are essential signalling molecules that co-ordinate the plant response to biotic and abiotic challenges, as well as co-ordinating several developmental processes. Huge progress has been made over the last decade in understanding the components and mechanisms that govern JA perception and signalling. The bioactive form of the hormone, (+)-7-iso-jasmonyl-l-isoleucine (JA-Ile), is perceived by the COI1–JAZ co-receptor complex. JASMONATE ZIM DOMAIN (JAZ) proteins also act as direct repressors of transcriptional activators such as MYC2. In the emerging picture of JA-Ile perception and signalling, COI1 operates as an E3 ubiquitin ligase that upon binding of JA-Ile targets JAZ repressors for degradation by the 26S proteasome, thereby derepressing transcription factors such as MYC2, which in turn activate JA-Ile-dependent transcriptional reprogramming. It is noteworthy that MYCs and different spliced variants of the JAZ proteins are involved in a negative regulatory feedback loop, which suggests a model that rapidly turns the transcriptional JA-Ile responses on and off and thereby avoids a detrimental overactivation of the pathway. This chapter highlights the most recent advances in our understanding of JA-Ile signalling, focusing on the latest repertoire of new targets of JAZ proteins to control different sets of JA-Ile-mediated responses, novel mechanisms of negative regulation of JA-Ile signalling, and hormonal cross-talk at the molecular level that ultimately determines plant adaptability and survival.

DIELECTRIC EVIDENCE FOR EXISTENCE OF TWO-LEVEL-SYSTEMS IN CYCLOHEXANOL, A " GLASSY CRYSTAL " SYSTEM

1982 ◽  
Vol 43 (C9) ◽  
pp. C9-525-C9-527
Author(s):  
G. P. Singh ◽  
R. Vacher ◽  
R. Calemczuk
Keyword(s):  
Crystal System ◽  
Two Level Systems

Inhibitory Feedback Loop Induces Anticipated Synchronization in Neuronal Networks

2014 ◽  
Vol 1 ◽  
pp. 636-639
Author(s):  
Fernanda S. Matias ◽  
Pedro V. Carelli ◽  
Claudio R. Mirasso ◽  
Mauro Copelli
Keyword(s):  
Feedback Loop ◽  
Neuronal Networks ◽  
Inhibitory Feedback
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