Modeling of Aircraft Prescribed Trajectory Flight as an Inverse Simulation Problem

2009 ◽  
pp. 153-162 ◽  
Author(s):  
Wojciech Blajer ◽  
Jerzy Graffstein ◽  
Mariusz Krawczyk
Keyword(s):  
Inverse Simulation ◽  
Simulation Problem

Dependent versus Independent Variable Formulation for the Dynamics and Control of Cranes

2009 ◽  
Vol 147-149 ◽  
pp. 221-230 ◽  
Author(s):  
Wojciech Blajer ◽  
Krzysztof Kołodziejczyk
Keyword(s):  
Degrees Of Freedom ◽  
Differential Algebraic Equations ◽  
Numerical Code ◽  
Underactuated System ◽  
Algebraic Equations ◽  
Underactuated Mechanical Systems ◽  
Performance Goal ◽  
Inverse Simulation ◽  
Simple Index ◽  
Simulation Problem

Cranes are underactuated mechanical systems with fewer control inputs than the degrees of freedom. Their usual performance goal is to execute a desired load trajectory, which is specified by as many outputs as the control inputs. A solution to the inverse simulation problem, in which the control of the underactuated system required to execute the partly specified motion is determined, is a challenging task. The inverse simulation study is usually formulated in independent variables. In this paper a dependent variable formulation is reported, advantageous in many aspects. The resultant governing equations appear as simple index-three differential-algebraic equations, and an effective numerical code for their solution is discussed.

A technique for predicting pilot model parameters using inverse simulation

2001 ◽  
Vol 105 (1044) ◽  
pp. 97-103 ◽  
Author(s):  
G. R. Leacock ◽  
D. G. Thomson
Keyword(s):  
Mathematical Model ◽  
Mathematical Models ◽  
Flight Test ◽  
Model Parameters ◽  
Inverse Simulation ◽  
Constrained Optimisation ◽  
Pilot Model ◽  
Compensatory Control ◽  
Time Histories ◽  
Simulation Problem

Abstract The practice of using mathematical models to simulate pilot behaviour in one–axis stabilisation tasks is a well–known conventional simulation problem. In this paper an accepted mathematical model of a pilot is used as the controller of a rudimentary helicopter model. Flight test manoeuvre data from inverse simulation runs is used to provide time–histories which represent input forcing functions to the pilot–helicopter system, and a constrained optimisation routine is utilised to obtain values for the pilot gain and lead/lag equalisation parameters. It will be shown that as the theoretical pilot is required to ‘fly’ different manoeuvres, or indeed if the level of manoeuvre aggression is varied, the ‘pilot’ adjusts these parameters to perform a tracking task in compensatory control. The paper considers initially the pilot and helicopter models and subsequently analyses the whole system, illustrating how the pilot model changes with different situations.

scholarly journals A Simulation Study of Helicopter Ship Landing Procedures Incorporating Measured Flow-Field Data

2005 ◽  
Vol 219 (5) ◽  
pp. 411-427 ◽  
Author(s):  
D G Thomson ◽  
F Coton ◽  
R Galbraith
Keyword(s):  
Wind Tunnel ◽  
Wind Loading ◽  
Atmospheric Conditions ◽  
Wind Tunnel Tests ◽  
Inverse Simulation ◽  
Ship Model ◽  
Measured Flow ◽  
Wind Profiles ◽  
The University ◽  
Flight Deck

The aim of this article is to investigate the use of inverse simulation to help identify those regions of a ship's flight deck which provide the safest locations for landing a rotorcraft in various atmospheric conditions. This requires appropriate information on the wind loading conditions around a ship deck and superstructure, and for the current work, these data were obtained from wind tunnel tests of a ship model representative of a typical helicopter carrier/assault ship. A series of wind tunnel tests were carried out on the model in the University of Glasgow's 2.65 × 2.04 m wind tunnel and three-axis measurements of wind speed were made at various locations on the ship deck. Measurements were made at four locations on the flight deck at three different heights. The choice of these locations was made on the basis of preliminary flow visualization tests which highlighted the areas where the most severe wind effects were most likely to occur. In addition, for the case where the wind was from 30° to starboard, measurements were made at three further locations to assess the extent of the wake of the superstructure. The generated wind profiles can then be imposed on the inverse simulation, allowing study of the vehicle and pilot response during a typical landing manoeuvre in these conditions. The power of the inverse simulation for this application is demonstrated by a series of simulations performed using configurational data representing two aircraft types, a Westland Lynx and a transport helicopter flying an approach and landing manoeuvre with the worst atmospheric conditions applied. It is shown from the results that attempting to land in the area aft of the superstructure in a 30° crosswind might lead to problems for the transport configuration due to upgusts in this area. Attempting to perform the landing manoeuvre in an aggressive manner is also shown to lead to diminished control margin in higher winds.

scholarly journals Accounting for Interelement Interferences in Atomic Emission Spectroscopy: A Nonlinear Theory

2021 ◽  
Vol 11 (23) ◽  
pp. 11237
Author(s):  
Anna N. Popova ◽  
Vladimir S. Sukhomlinov ◽  
Aleksandr S. Mustafaev
Keyword(s):  
Nonlinear Theory ◽  
Emission Spectroscopy ◽  
High Speed ◽  
Atomic Emission ◽  
Carbon Steels ◽  
Atomic Emission Spectroscopy ◽  
Spectral Lines ◽  
Analytical Line ◽  
Simulation Problem ◽  
Heat Resistant Steels

The article describes a nonlinear theory of how the presence of third elements affects the results of analyzing the elemental composition of substances by means of atomic emission spectroscopy. The theory is based on the assumption that there is an arbitrary relationship between the intensity of the analytical line of the analyte and the concentration of impurities and alloying elements. The theory has been tested on a simulation problem using commercially available equipment (the SPAS-05 spark spectrometer). By comparing the proposed algorithm with the traditional one, which assumes that there is a linear relationship between the intensity of the analytical line of the analyte and the intensities of the spectral lines (or concentrations) in the substance, it was revealed that there is a severalfold decrease in the deviations of nominal impurity concentrations from the measured ones. The results of this study allow for reducing the number of analytical procedures used in analyzing materials that have different compositions and the same matrix element. For instance, it becomes possible to determine the composition of iron-based alloys (low-alloy and carbon steels; high-speed steels; high-alloy, and heat-resistant steels) using one calibration curve within the framework of a universal analytical method.

scholarly journals Registration by interactive inverse simulation: application for adaptive radiotherapy

2015 ◽  
Vol 10 (8) ◽  
pp. 1193-1200 ◽  
Author(s):  
Eulalie Coevoet ◽  
Nick Reynaert ◽  
Eric Lartigau ◽  
Luis Schiappacasse ◽  
Jérémie Dequidt ◽  
...  
Keyword(s):  
Adaptive Radiotherapy ◽  
Inverse Simulation

Dynamics Analysis of Aircraft Landing on the Pitching Deck

2011 ◽  
Vol 467-469 ◽  
pp. 579-582 ◽  
Author(s):  
Zhen Qing Wang ◽  
Xiao Yu Sun ◽  
Song Zhou ◽  
Hong Shuai Lei
Keyword(s):  
Coordinate System ◽  
Dynamics Analysis ◽  
Dynamics Model ◽  
Aircraft Landing ◽  
Complex Simulation ◽  
Simulation Problem

In order to study the aircraft landing on the deck, the landing(on or off center) dynamics model of airplane on deck is built.In this model,the interactions of the aircraft landing attitude , the arresting force acting on the aircraft are considered,and the influence of dynamic deck is introduced into the model .The deck coordinate system is put forward to solve the complex simulation problem..At last,by simulation,it is demonstrated that the model can be applied to the aircraft landing attitude,it is also proved that the model is comprehensive and suitable for any abnormal landing situation.

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