Short wide angle diffuser with pulse jet control

1999 ◽  
Author(s):  
S. Raghunathan ◽  
J. Watterson ◽  
R. Cooper ◽  
S. Lee
Keyword(s):  
Wide Angle ◽  
Jet Control ◽  
Pulse Jet

Pulse-frequency modulated guidance laws for a mortar missile with a pulse jet control mechanism

2015 ◽  
Vol 119 (1213) ◽  
pp. 389-405 ◽  
Author(s):  
M. Pavic ◽  
B. Pavkovic ◽  
S. Mandic ◽  
S. Zivkovic ◽  
D. Cuk
Keyword(s):  
Sliding Mode ◽  
Design Parameters ◽  
Proportional Navigation ◽  
Adaptive Sliding Mode ◽  
Jet Control ◽  
Control Authority ◽  
The Individual ◽  
Miss Distance ◽  
Guidance Laws ◽  
Pulse Jet

AbstractThe impact point dispersion of mortar missiles can be drastically reduced with a control ring of lateral pulse jets located around the centre of gravity and a homing head to measure or to derive estimates of appropriate missile-target states, e.g. the line-of-sight rates. A simulation model including a missile as a six-degree-of-freedom vehicle, a jet pulse flight control system, and a relative missile-to-target motion was used for the comparison of four guidance laws i.e. proportional navigation guidance, augmented proportional navigation, augmented proportional navigation with rendezvous, and adaptive sliding-mode guidance. This paper focuses on the efficiency of pulse jet control on miss distance, and thus makes the assumption that sensor measurements and the guidance states required to apply each of the guidance laws are perfectly known. Proportional navigation and the adaptive sliding mode guidance exhibit a large miss distance due to limited control authority. Augmented proportional navigation is slightly better than augmented proportional navigation with rendezvous for the same design parameters and they both give small miss distances with limited control authority, but they both require a free gyro. A proper selection of the design parameters — the number of pulse jets and the magnitude of the individual pulse jet thrust for a particular dispersion of flight parameters and the instant of the guidance start — is required to achieve optimum dispersion reduction. The minimum intensity of the individual pulse jet impulse required for the ‘pin point’ accuracy (the circular error probable smaller than 1m) of the mortar missile was determined for all presented guidance laws considering dispersion from the nominal trajectory.

Frequency-Modulated Pulse-Jet Control of an Artillery Rocket

2012 ◽  
Vol 49 (2) ◽  
pp. 286-294 ◽  
Author(s):  
Bojan Pavkovic ◽  
Milos Pavic ◽  
Danilo Cuk
Keyword(s):  
Jet Control ◽  
Pulse Jet

Intelligent Optimal Pulse-Jet Control for Dual-Spin Projectiles

2021 ◽  
Author(s):  
Zhen Yang ◽  
Jian Fu ◽  
Liangming Wang ◽  
Zhi Chen
Keyword(s):  
Jet Control ◽  
Pulse Jet

Model Predictive Lateral Pulse Jet Control of an Atmospheric Rocket

2002 ◽  
Vol 25 (5) ◽  
pp. 860-867 ◽  
Author(s):  
Bradley Burchett ◽  
Mark Costello
Keyword(s):  
Jet Control ◽  
Lateral Pulse Jet ◽  
Pulse Jet

CBED Shadow Images and Cs:Aberration Measurement

1982 ◽  
Vol 40 ◽  
pp. 696-697
Author(s):  
R. W. Carpenter ◽  
I.Y.T. Chan ◽  
J. M. Cowley
Keyword(s):  
Focal Point ◽  
Spherical Aberration ◽  
Optic Axis ◽  
Wide Angle ◽  
Caustic Surface ◽  
Convergent Beam

Wide-angle convergent beam shadow images(CBSI) exhibit several characteristic distortions resulting from spherical aberration. The most prominent is a circle of infinite magnification resulting from rays having equal values of a forming a cross-over on the optic axis at some distance before reaching the paraxial focal point. This distortion is called the tangential circle of infinite magnification; it can be used to align and stigmate a STEM and to determine Cs for the probe forming lens. A second distortion, the radial circle of infinite magnification, results from a cross-over on the lens caustic surface of rays with differing values of ∝a, also before the paraxial focal point of the lens.

Reconstruction of Chitin-Protein Complexes Using Correlation Averaging Methods: Ovipositor of the Ichneumon Fly Megarhyssa

1980 ◽  
Vol 38 ◽  
pp. 38-39
Author(s):  
L. T. Germinario ◽  
J. Blackwell ◽  
J. Frank
Keyword(s):  
Protein Complexes ◽  
Hexagonal Lattice ◽  
Uranyl Acetate ◽  
Optical Diffraction ◽  
Insect Cuticle ◽  
High Dose ◽  
Wide Angle ◽  
X Ray ◽  
Averaging Methods ◽  
Digital Correlation

This report describes the use of digital correlation and averaging methods 1,2 for the reconstruction of high dose electron micrographs of the chitin-protein complex from Megarhyssa ovipositor. Electron microscopy of uranyl acetate stained insect cuticle has demonstrated a hexagonal array of unstained chitin monofibrils, 2.4−3.0 nm in diameter, in a stained protein matrix3,4. Optical diffraction Indicated a hexagonal lattice with a = 5.1-8.3 nm3 A particularly well ordered complex is found in the ovipositor of the ichneumon fly Megarhyssa: the small angle x-ray data gives a = 7.25 nm, and the wide angle pattern shows that the protein consists of subunits arranged in a 61 helix, with an axial repeat of 3.06 nm5.

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