Active Transparent Stall Control System for Air Vehicles

2003 ◽  
Vol 40 (5) ◽  
pp. 993-997 ◽  
Author(s):  
Mehul P. Patel ◽  
Carl P. Tilmann ◽  
T. Terry Ng
Keyword(s):  
Control System ◽  
Stall Control ◽  
Air Vehicles

Active Transparent Stall Control System for Air Vehicles

10.2514/1.326 ◽  
2003 ◽  
Vol 40 (5) ◽  
Author(s):  
Mehul P. Patel ◽  
Carl P. Tilmann ◽  
Terry Ng
Keyword(s):  
Control System ◽  
Stall Control ◽  
Air Vehicles

Tests of an Improved Rotating Stall Control System on a J-85 Turbojet Engine

1980 ◽  
Vol 102 (4) ◽  
pp. 903-911 ◽  
Author(s):  
G. R. Ludwig ◽  
J. P. Nenni
Keyword(s):  
Control System ◽  
Response Time ◽  
Detection System ◽  
Response Speed ◽  
Rotating Stall ◽  
The Past ◽  
Turbojet Engine ◽  
Design Speed ◽  
Stall Control ◽  
Selection Of

An improved version of a rotating stall control system has been tested successfully on a J-85-B turbojet engine. Past tests had pointed out the desirability of increasing the response speed of the control. In this study, the installation of the stall control on the J-85 was modified so as to decrease the response time of the control by a factor of ten over that attained in the past tests. The modified control was tested to see if the decreased response time improved the ability to clear rotating stall once it has started, and also to see if rotating stall could be anticipated and prevented by proper selection of the variables in the stall control detection system. The performance of the stall control was tested by closing the bleed doors on the engine until rotating stall occurred or until the control anticipated stall and held the bleed doors open. The tests showed that the control is capable of anticipating stall before it occurs and keeping the engine completely clear of stall at speeds up to 80 percent of design speed. No tests were performed above 80 percent of design speed because opening the bleed doors at such speeds might aggravate the stall rather than clear it.

A Rotating Stall Control System for Turbojet Engines

1979 ◽  
Vol 101 (3) ◽  
pp. 305-313 ◽  
Author(s):  
G. R. Ludwig ◽  
J. P. Nenni
Keyword(s):  
Control System ◽  
Rotating Stall ◽  
Prototype System ◽  
Variable Geometry ◽  
Hydraulic Actuator ◽  
Low Speed ◽  
Correction Signal ◽  
Geometry Feature ◽  
Stall Control ◽  
Stagger Angle

This paper describes the operating principle of a rotating stall control system and the results of testing a prototype control on a low-speed research compressor and on a J-85-5 turbojet engine. The control is an electrical feed-back control system which uses unsteady pressure signals produced by sensors within the compressor to detect the presence of stall and provide a correction signal when stall occurs. In the prototype system, the correction signal is used to drive a hydraulic actuator which provides a mechanical operation on some variable geometry feature of the compressor being controlled. On the low-speed research compressor the variable geometry was the stagger angle of the stator rows. On the J-85 engine, the control was installed to override the normal operating schedule of the compressor bleed doors and flaps on the inlet guide vanes. Both series of tests were successful in that the control rapidly eliminated rotating stall when it occurred and in some cases did not allow rotating stall to occur at all.

Video Tracking Control Algorithms for Unmanned Air Vehicles

2008 ◽  
Author(s):  
Ricardo Bencatel ◽  
Joa˜o Correia ◽  
Joa˜o Borges Sousa ◽  
Gil M. Gonc¸alves ◽  
Elo´i Pereira
Keyword(s):  
Control System ◽  
Flight Control ◽  
Tracking Control ◽  
Video Tracking ◽  
Control Algorithms ◽  
Unmanned Air Vehicles ◽  
Hybrid Automata ◽  
Simulation Environment ◽  
Flight Control System ◽  
Air Vehicles

We present and discuss a modular flight control system suitable for video tracking natural structures with Unmanned Air Vehicles (UAVs), like rivers, roads or canals. The control system is modeled in the framework of hybrid automata, where each state corresponds to different control algorithms. We implemented four nonlinear turn-rate control algorithms and compared them in a simulation environment to assess tracking performance.

Closed-Loop Stall Control System

2010 ◽  
Vol 47 (5) ◽  
pp. 1747-1755 ◽  
Author(s):  
Jonathan Poggie ◽  
Carl P. Tilmann ◽  
Peter M. Flick ◽  
Joseph S. Silkey ◽  
Bradley A. Osbourne ◽  
...  
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Stall Control

scholarly journals Stall Inception and the Prospects for Active Control in Four High Speed Compressors

1997 ◽  
Author(s):  
I. J. Day ◽  
T. Breuer ◽  
J. Escuret ◽  
M. Cherrett ◽  
A. Wilson
Keyword(s):  
Control System ◽  
Active Control ◽  
High Speed ◽  
Rotating Stall ◽  
Collaborative Project ◽  
Stall Inception ◽  
Speed Range ◽  
Full Speed ◽  
Stall Warning ◽  
Stall Control

As part of a European collaborative project, four high speed compressors were tested to investigate the generic features of stall inception in aero-engine type compressors. Tests were run over the full speed range to identify the design and operating parameters which influence the stalling process. A study of data analysis techniques was also conducted in the hope of establishing early warning of stall. The work presented here is intended to relate the physical happenings in the compressor to the signals that would be received by an active stall control system. The measurements show a surprising range of stall related disturbances and suggest that spike-type stall inception is a feature of low speed operation while modal activity is clearest in the mid speed range. High frequency disturbances were detected at both ends of the speed range and non-rotating stall, a new phenomenon, was detected in three out of the four compressors. The variety of the stalling patterns, and the ineffectiveness of the stall warning procedures, suggests that the ultimate goal of a flightworthy active control system remains some way off.

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