The multiple-function multi-input/multi-output digital controller system for the AFW wind-tunnel model

A real time multiple-function digital controller system was developed for the Active Flexible Wing (AFW) Program. The digital controller system (DCS) allowed simultaneous execution of two control laws: flutter suppression and either roll trim or a rolling maneuver load control. The DCS operated within, but independently of, a slower host operating system environment, at regulated speeds up to 200 Hz. It also coordinated the acquisition, storage, and transfer of data for near real time controller performance evaluation and both open- and closed-loop plant estimation. It synchronized the operation of four different processing units, allowing flexibility in the number, form, functionality, and order of control laws, and variability in the selection of the sensors and actuators employed. Most importantly, the DCS allowed for the successful demonstration of active flutter suppression to conditions approximately 26 percent (in dynamic pressure) above the open-loop boundary in cases when the model was fixed in roll and up to 23 percent when it was free to roll. Aggressive roll maneuvers with load control were achieved above the flutter boundary. The purpose here is to present the development, validation, and wind tunnel testing of this multiple-function digital controller system

Modern Indonesian Administration: Collegial, Abdi-Dalem, Rational-, or Ideological- Bureaucratic?

Meskipun rezim Suharto telah Jatuh) selama lebih dari dua tahun dan Indonesia telah melaksanakan pemilu yang paling adil selama setengab abad usia kemerdekaan, namun tetap belum juga muncul hasil yang cukup berarti dalam reformasi di Indonesia. Tipe birokrasi Indonesia diduga telah menjadi factor penyebab kemandegan langkah reformasi ini. Tulisan ini mencoba mencari penjelasan mengenai sebab-sebab buruknya implementasi kebijakan dari akar kesejarahan yaitu dari keterbatasan-keterbatasan kelembagaan

Revitalize and Reposition Indonesian Public Administration, the Legacy of Law

Tulisan ini mencoba menggunakan pendekatan atau perspektif historis dalam upaya untuk mencari model yang asli untuk pelaksanaan otonomi daerah. Dengan pendekatan historis ditelusuri pelaksanaan administrasi publik yang bersumber dari adat istiadat Jawa, masa pemerintahan Hindia Belanda dan Masa Republik pada tahun 1945. Pendekatan administrasi yang digunakan dalam adat istiadat Jawa adalah konsensus dan dekrit. Dalam pemerintahan Hindia Belanda terjadi penggabungan antara adat-istiadat dengan berbagai ketentuan yang dikembangkan oleh Belanda. Dalam era Republik terjadi tarik menarik antara peraturan yang bersifat positivisme dan romantisme. Model yang diajukan adalah adanya kombinasi antara adat, peraturan yang berlaku dalam masa kolonial dan peraturan yang dihasilkan dari penguasa yang ada sekarang ini

On-line analysis capabilities developed to support the AFW wind-tunnel tests

A variety of on-line analysis tools were developed to support two active flexible wing (AFW) wind-tunnel tests. These tools were developed to verify control law execution, to satisfy analysis requirements of the control law designers, to provide measures of system stability in a real-time environment, and to provide project managers with a quantitative measure of controller performance. Descriptions and purposes of the developed capabilities are presented along with examples. Procedures for saving and transferring data for near real-time analysis, and descriptions of the corresponding data interface programs are also presented. The on-line analysis tools worked well before, during, and after the wind tunnel test and proved to be a vital and important part of the entire test effort

Multiple-function multi-input/multi-output digital control and on-line analysis

The design and capabilities of two digital controller systems for aeroelastic wind-tunnel models are described. The first allowed control of flutter while performing roll maneuvers with wing load control as well as coordinating the acquisition, storage, and transfer of data for on-line analysis. This system, which employs several digital signal multi-processor (DSP) boards programmed in high-level software languages, is housed in a SUN Workstation environment. A second DCS provides a measure of wind-tunnel safety by functioning as a trip system during testing in the case of high model dynamic response or in case the first DCS fails. The second DCS uses National Instruments LabVIEW Software and Hardware within a Macintosh environment

Development, simulation validation, and wind tunnel testing of a digital controller system for flutter suppression

Flutter suppression (FS) is one of the active control concepts being investigated by the AFW program. The design goal for FS control laws was to increase the passive flutter dynamic pressure by 30 percent. In order to meet this goal, the FS control laws had to be capable of suppressing both symmetric and antisymmetric flutter instabilities simultaneously. In addition, the FS control laws had to be practical and low-order, robust and capable of real time execution within the 200 hz. sampling time. The purpose here is to present an overview of the development, simulation validation, and wind tunnel testing of a digital controller system for flutter suppression

ISAC: A tool for aeroservoelastic modeling and analysis

The capabilities of the Interaction of Structures, Aerodynamics, and Controls (ISAC) system of program modules is discussed. The major modeling, analysis, and data management components of ISAC are identified. Equations of motion are displayed for a Laplace-domain representation of the unsteady aerodynamic forces. Options for approximating a frequency-domain representation of unsteady aerodynamic forces with rational functions of the Laplace variable are shown. Linear time invariant state-space equations of motion that result are discussed. Model generation and analyses of stability and dynamic response characteristics are shown for an aeroelastic vehicle which illustrates some of the capabilities of ISAC as a modeling and analysis tool for aeroelastic applications