A necessary condition for nonlinear control via measurement feedback

1994 ◽  
Vol 23 (3) ◽  
pp. 169-177 ◽  
Author(s):  
Alberto Isidori
Keyword(s):  
Nonlinear Control ◽  
Necessary Condition ◽  
Measurement Feedback

Event-triggered composite nonlinear control for saturated systems with measurement feedback

2019 ◽  
Vol 41 (14) ◽  
pp. 3943-3951 ◽  
Author(s):  
Zhiqiang Zuo ◽  
Haorui Cheng ◽  
Yijing Wang ◽  
Hongchao Li
Keyword(s):  
Nonlinear Control ◽  
Design Method ◽  
Time Interval ◽  
Nonlinear Feedback ◽  
Composite Nonlinear Feedback ◽  
Fighter Aircraft ◽  
Event Triggering ◽  
Measurement Feedback ◽  
Control Part ◽  
Event Triggered

The composite nonlinear feedback (CNF) control problem with event-triggered strategy for saturated systems with measurement feedback is considered in this paper. Both the full-order measurement and the reduced-order one are investigated to ensure the satisfactory performance of the closed-loop saturated systems under the proposed event-triggered mechanism. Generally speaking, the CNF control is divided into the linear control part and the nonlinear control part, which are designed separately. The purpose of the former is to shorten the rise time, while the latter aims at reducing the overshoot caused by the former. In this paper, a co-design method of linear and nonlinear control parts is proposed such that the control output tracks the reference input asymptotically with a good transient performance. Moreover, the parameter of CNF is applied to the construction of event-triggered mechanism which can efficiently reduce the communication burden. In order to avoid Zeno behavior, the minimum event-triggering time interval is explicitly formulated. Finally, an example of fighter aircraft is given for illustration.

Design of the Nonlinear Structure Adaptive Model Inversion Flight Control System

2016 ◽  
Vol 28 (6) ◽  
pp. 928-935
Author(s):  
Hao Long ◽  
◽  
Yi-Nung Chung ◽  
Keyword(s):  
Control System ◽  
Nonlinear Control ◽  
Flight Control ◽  
Necessary Condition ◽  
Adaptive Model ◽  
Flight Control System ◽  
Nonlinear Structure ◽  
Model Inversion ◽  
Text Design ◽  
Sufficient And Necessary Condition

[abstFig src='/00280006/17.jpg' width='300' text='Design of the nonlinear SAMI flight control system' ] The advanced aircraft has those technological characteristics: stealth, supersonic cruise, super maneuverability, multi-target attack, multi-role, high load, long range cruise, integrated avionics, short takeoffs and vertical landings. These characteristics need multi-subsystem integration in the advanced aircraft. In order to meet the need of advance aircraft, the nonlinear control system is necessary. In this paper, the nonlinear structure adaptive model inversion system was first used for the nonlinear control problem of super-maneuver aircraft. The sufficient and necessary condition of the control law was analyzed. Finally the results of the height-angle maneuver simulation show that the designed control system has good performance.

The Infancy of Solar-Type Stars and its Relevance for the Origin of Life

1997 ◽  
Vol 161 ◽  
pp. 267-282 ◽  
Author(s):  
Thierry Montmerle
Keyword(s):  
Main Sequence ◽  
Solar Nebula ◽  
Circumstellar Disks ◽  
T Tauri Stars ◽  
Necessary Condition ◽  
Sequence Evolution ◽  
T Tauri ◽  
Solar Type ◽  
Optical Domain ◽  
The Origin Of Life

AbstractFor life to develop, planets are a necessary condition. Likewise, for planets to form, stars must be surrounded by circumstellar disks, at least some time during their pre-main sequence evolution. Much progress has been made recently in the study of young solar-like stars. In the optical domain, these stars are known as «T Tauri stars». A significant number show IR excess, and other phenomena indirectly suggesting the presence of circumstellar disks. The current wisdom is that there is an evolutionary sequence from protostars to T Tauri stars. This sequence is characterized by the initial presence of disks, with lifetimes ~ 1-10 Myr after the intial collapse of a dense envelope having given birth to a star. While they are present, about 30% of the disks have masses larger than the minimum solar nebula. Their disappearance may correspond to the growth of dust grains, followed by planetesimal and planet formation, but this is not yet demonstrated.

Universal ESEM

1993 ◽  
Vol 51 ◽  
pp. 786-787
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Vacuum ◽  
Natural Extension ◽  
Necessary Condition ◽  
Environmental Scanning ◽  
Detection Systems ◽  
Small Gain ◽  
Detection Medium ◽  
Scanning Electron

The environmental scanning electron microscope (ESEM) has evolved as the natural extension of the scanning electron microscope (SEM), both historically and technologically. ESEM allows the introduction of a gaseous environment in the specimen chamber, whereas SEM operates in vacuum. One of the detection systems in ESEM, namely, the gaseous detection device (GDD) is based on the presence of gas as a detection medium. This might be interpreted as a necessary condition for the ESEM to remain operational and, hence, one might have to change instruments for operation at low or high vacuum. Initially, we may maintain the presence of a conventional secondary electron (E-T) detector in a "stand-by" position to switch on when the vacuum becomes satisfactory for its operation. However, the "rough" or "low vacuum" range of pressure may still be considered as inaccessible by both the GDD and the E-T detector, because the former has presumably very small gain and the latter still breaks down.

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