Control system for the William Herschel Telescope: performance and recent developments

1995 ◽  
Author(s):  
Robert A. Laing
Keyword(s):  
Control System ◽  
Recent Developments ◽  
William Herschel

Modeling and Simulation of Controlled Manipulation by AFM Nano Robot

2011 ◽  
Vol 110-116 ◽  
pp. 3688-3695 ◽  
Author(s):  
Ali Kafash Hoshiar ◽  
Mohamad Reza Khalili ◽  
Mahmood Hashemi Nejad ◽  
Hafez Raeisi Fard
Keyword(s):  
Finite Element ◽  
Control System ◽  
Process Control ◽  
Control Algorithm ◽  
State Space Model ◽  
Force Transducer ◽  
Process Control System ◽  
Space Model ◽  
Element Simulation ◽  
Recent Developments

In this article a model to describe relation between AFM cantilever’s deformation and force (as a force transducer) is developed. Furthermore a state space model is used to find suitable feedback control. A model which relates force and deformation is described. To verify a Finite element simulation is applied and a control algorithm for manipulation purpose is found. Moreover based on nature of the process control system is designed. Due to recent developments in AFM nanorobot applications in biotechnology and manufacturing nanostructures, understanding of cantilever’s response and process control have received great importance.

Decentralized Control of Structural Acoustic Radiation

2001 ◽  
Author(s):  
Kenneth D. Frampton
Keyword(s):  
Control System ◽  
Decentralized Control ◽  
Large Scale ◽  
Acoustic Radiation ◽  
Electrical Power ◽  
Computational Effort ◽  
Centralized Control ◽  
Mems Devices ◽  
Sensors And Actuators ◽  
Recent Developments

Abstract Although the application of active control to vibrations has been investigated from many years, the extension of this technology to large-scale systems has been thwarted, in part, by an overwhelming need for computational effort, data transmission and electrical power. This need has been overwhelming in the sense that the potential applications are unable to bear the power, weight and complex communications requirement of large-scale centralized control systems. Recent developments in MEMS devices and networked embedded devices have changed the focus of such applications from centralized control architectures to decentralized ones. A decentralized control system is one that consists of many autonomous, or semi-autonomous, localized controllers called nodes, acting on a single plant, in order to achieve a global control objective. Each of these nodes has the following capabilities and assets: 1) a relatively limited computational capability including limited memory, 2) oversight of a suite of sensors and actuators and 3) a communications link (either wired or wireless) with neighboring or regional nodes. The objective of a decentralized controller is the same as for a centralized control system: to maintain some desirable global system behavior in the presences of disturbances. However, decentralized controllers do so with each node possessing only a limited amount of information on the global systems response. Exactly what information each node has access to, and how that information is used, is the topic of this investigation.

scholarly journals The hardware control system for WEAVE at the William Herschel telescope

2014 ◽  
Author(s):  
Jose M. Delgado Hernandez ◽  
Luis F. Rodríguez-Ramos ◽  
Diego Cano Infantes ◽  
Carlos Martin ◽  
Craige Bevil ◽  
...  
Keyword(s):  
Control System ◽  
William Herschel

scholarly journals The hardware control system for WEAVE at the William Herschel Telescope

2018 ◽  
Author(s):  
José Miguel Delgado Hernández ◽  
José Alonso Burgal ◽  
José Miguel Herreros Linares ◽  
Jose Alfonso López Aguerri ◽  
Don Carlos Abrams ◽  
...  
Keyword(s):  
Control System ◽  
William Herschel

CONTROL SYSTEM FOR REMOTE SUBSEA COMPLETIONS

1991 ◽  
Vol 31 (1) ◽  
pp. 396
Author(s):  
W.C. Henry
Keyword(s):  
Control System ◽  
Joint Venture ◽  
Lower Cost ◽  
Production Control ◽  
Control Techniques ◽  
Electrohydraulic System ◽  
Production Control System ◽  
Long Offset ◽  
Recent Developments ◽  
Gas Lift

The Seahorse and Tarwhine subsea completions are among a number of recent developments in Bass Strait designed to exploit relatively small and remote fields. Both wells have been developed by re-entering and completing the original exploration wells and tying them back to the nearest existing platform, Barracouta, with an insulated production flowline, a gas lift supply line, and an electrohydraulic control umbilical. Seahorse is a little over 11 km north, and Tarwhine almost 18 km south-west of Barracouta, and it is these long offset distances which significantly influenced the decision to adopt an electrohydraulic control system. The advantages of an electrohydraulic system in this application, compared to the other control techniques available, are that it provides a faster response time to surface initiated commands, it has an overall lower cost, and it provides information back to the surface about conditions at the subsea well.Many of the components used in the subsea production control system are innovative and highly specialised, for example, the conductive electrical couplers and the temperature transducers. A significant amount of the equipment also has its origins in the aerospace industry and, like in that industry, demands a high commitment to quality assurance and quality control throughout the manufacturing and assembly phases of the project. Seahorse and Tarwhine have now been producing successfully since September and May 1990, respectively. The success of this project gives the joint venture partners, Esso and BHPP, confidence to use subsea technology to continue developing smaller fields, particularly as developments move into deeper water approaching and beyond the edge of the continental shelf.

Trends in Electron Energy Loss Spectroscopy

1977 ◽  
Vol 35 ◽  
pp. 228-229
Author(s):  
C. Colliex ◽  
P. Trebbia
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Analytical Technique ◽  
Recent Developments ◽  
Quantitative Results ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Primary Electrons

The physical foundations for the use of electron energy loss spectroscopy towards analytical purposes, seem now rather well established and have been extensively discussed through recent publications. In this brief review we intend only to mention most recent developments in this field, which became available to our knowledge. We derive also some lines of discussion to define more clearly the limits of this analytical technique in materials science problems.The spectral information carried in both low ( 0<ΔE<100eV ) and high ( >100eV ) energy regions of the loss spectrum, is capable to provide quantitative results. Spectrometers have therefore been designed to work with all kinds of electron microscopes and to cover large energy ranges for the detection of inelastically scattered electrons (for instance the L-edge of molybdenum at 2500eV has been measured by van Zuylen with primary electrons of 80 kV). It is rather easy to fix a post-specimen magnetic optics on a STEM, but Crewe has recently underlined that great care should be devoted to optimize the collecting power and the energy resolution of the whole system.

Filaments and membranes in the mitotic apparatus

1983 ◽  
Vol 41 ◽  
pp. 544-547
Author(s):  
Kent McDonald
Keyword(s):  
Intermediate Filaments ◽  
Mitotic Spindle ◽  
Mitotic Apparatus ◽  
Light Microscope Level ◽  
Microtubule Associated Proteins ◽  
Recent Developments ◽  
Associated Proteins ◽  
Force Generator ◽  
Spindle Function ◽  
Antibody Technology

At the light microscope level the recent developments and interest in antibody technology have permitted the localization of certain non-microtubule proteins within the mitotic spindle, e.g., calmodulin, actin, intermediate filaments, protein kinases and various microtubule associated proteins. Also, the use of fluorescent probes like chlorotetracycline suggest the presence of membranes in the spindle. Localization of non-microtubule structures in the spindle at the EM level has been less rewarding. Some mitosis researchers, e.g., Rarer, have maintained that actin is involved in mitosis movements though the bulk of evidence argues against this interpretation. Others suggest that a microtrabecular network such as found in chromatophore granule movement might be a possible force generator but there is little evidence for or against this view. At the level of regulation of spindle function, Harris and more recently Hepler have argued for the importance of studying spindle membranes. Hepler also believes that membranes might play a structural or mechanical role in moving chromosomes.

A controller for safe, convenient operation of LaB6 emitters on electron-beam instruments

1983 ◽  
Vol 41 ◽  
pp. 408-409
Author(s):  
W. J. Abramson ◽  
H. W. Estry ◽  
L. F. Allard
Keyword(s):  
Electron Beam ◽  
Control System ◽  
Thermal Shock ◽  
Appropriate Care ◽  
Electron Guns ◽  
Tungsten Filaments ◽  
Order Of Magnitude ◽  
Main Components

LaB6 emitters are becoming increasingly popular as direct replacements for tungsten filaments in the electron guns of modern electron-beam instruments. These emitters offer order of magnitude increases in beam brightness, and, with appropriate care in operation, a corresponding increase in source lifetime. They are, however, an order of magnitude more expensive, and may be easily damaged (by improper vacuum conditions and thermal shock) during saturation/desaturation operations. These operations typically require several minutes of an operator's attention, which becomes tedious and subject to error, particularly since the emitter must be cooled during sample exchanges to minimize damage from random vacuum excursions. We have designed a control system for LaBg emitters which relieves the operator of the necessity for manually controlling the emitter power, minimizes the danger of accidental improper operation, and makes the use of these emitters routine on multi-user instruments.Figure 1 is a block schematic of the main components of the control system, and Figure 2 shows the control box.

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