Aircraft Engineering and Aerospace Technology

Particle swarm optimization for GPS navigation Kalman filter adaptation : Table of Contents

Dah-Jing Jwo, Shun-Chieh Chang — Sun Jun 14 14:15:06 BST 2009

Abstract:
Purpose – The purpose of this paper is to conduct the particle swarm optimization (PSO)-assisted adaptive Kalman filter (AKF) for global positioning systems (GPS) navigation processing. Performance evaluation for the PSO-assisted Kalman filter (KF) as compared to the conventional KF is provided. Design/methodology/approach – The position-velocity also knows as constant velocity process model can be applied to the GPS KF adequately when navigating a vehicle with constant speed. However, when an abrupt acceleration motion occurs, the filtering solution becomes very poor or even diverges. To avoid the limitation of the KF, the PSO can be incorporated into the filtering mechanism as dynamic model corrector. The PSO is utilized as the noise-adaptive mechanism to tune the covariance matrix of process noise and overcome the deficiency of KF. In other words, PSO-assisted KF approach is employed for tuning the covariance of the GPS KF so as to reduce the estimation error during substantial maneuvering. Findings – The paper provides an alternative approach for designing an AKF and provides an example in the application to GPS. Practical implications – The proposed scheme enhances the improvement in estimation accuracy. Application of the PSO to the GPS navigation filter design is discussed. The method takes advantage of both the adaptation capability and the robustness of numerical stability. Originality/value – The PSO are employed for assisting the AKF. The use of optimization such as PSO for AKF has seldom been seen in the open literature.

The turbo fan aircraft minimum cost climb technique : Table of Contents

P. Mirosavljevic, S. Gvozdenovic, O. Cokorilo — Sun Jun 14 14:15:06 BST 2009

Abstract:
Purpose – The purpose of this paper is to define minimum cost technique of turbo fan transport aircraft in the presence of dynamic change of aircraft performance. Results can be practical applicable in airlines for achieving minimal operation costs. Design/methodology/approach – Logarithmic differential is applied for defining conditions in order to achieve optimal Mach number for minimal climb cost. This condition is solved numerically by using Newton-Ramphson method, to obtain optimal Mach number distribution with altitude. Conclusion about optimal top of climb (TOC) is defined after analyses for different aircraft mass and cost indexes. Findings – Proposed method of minimum cost climb resulting in potential savings up to 5 per cent compared to Aircraft Flight Manual climb law. Proposed method also made correction of climb law and optimal TOC under existence of aircraft performance degradation. Practical implications – Use of defined climb law and optimal TOC will minimize cost of en route flight profile. Originality/value – At present, there is no definition of climb technique for minimum cost of en route flight profile, under dynamic degradation of aircraft performance. Final results are standardized to become applicable and easy to use with modern and old type of flight management system.

Single-range controller design for a cruise missile : Table of Contents

Amir Nassirharand, S.R. Mousavi Firdeh — Sun Jun 14 14:15:06 BST 2009

Abstract:
Purpose – The purpose of this paper is to describe the application of a systematic single-range controller design procedure to control a cruise missile. Design/methodology/approach – The controller design approach is based on one describing function model of the missile followed by linear system identification. The missile includes discontinuous nonlinear terms, and therefore, a small signal model is not obtainable by straight linearization. Once a linear approximation to the quasilinear model of the missile is obtained, a H8 controller is designed to achieve a robust nonlinear closed-loop system. Findings – It is found that performance of the closed-loop system with the applied simple controller design approach competes with one other complicated describing function-based controller design technique. Research limitations/implications – At present, the research is limited to design of linear H8 controllers. Practical implications – The major outcome of this paper is the verification that the applied simple describing function-based H8 controller design procedure may be used to design high-performance controllers for cruise missiles. Originality/value – This is the first paper that adopts an existing single-range H8 controller design procedure to design high-performance controllers for cruise missiles.

Active vibration control of a laminated composite plate subjected to blast load : Table of Contents

Haydar Uyanik, Zahit Mecitoglu — Sun Jun 14 14:15:06 BST 2009

Abstract:
Purpose – The purpose of this paper is to develop a structural vibration control system by using a state observer which estimates system states using displacements measured from sensors. Design/methodology/approach – Friedlander's exponential decay function is used for expressing the blast load model. A semiloof shell element is developed in order to account for piezoelectric effects. The composite plate is discretized by using the semiloof shell elements, and stiffness and mass matrices of the plate are obtained from the finite element model. In order to reduce the degrees of freedom of the finite element model, mode summation method is used with weighted modal vector including initial dominant modes in the dynamic behavior. Findings – The structural vibrations are suppressed successfully and in an optimal way by using a state observer control system which estimates system states using displacements measured from sensors. Originality/value – This paper shows, for the first time, that vibrations of a cantilevered composite plate subjected to blast loading are suppressed by the use of piezoelectric actuators. The state observer and optimal linear quadratic regulator are both used at the same time to suppress the vibrations.

Modelling and simulation of mechanical transmission in roller-screw electromechanical actuators : Table of Contents

Wissam Karam, Jean-Charles Mare — Sun Jun 14 14:15:06 BST 2009

Abstract:
Purpose – The purpose of this paper is to develop accurate model and simulation of mechanical power transmission within roller-screw electromechanical actuators with special attention to friction, compliance and inertia effects. Also, to propose non-intrusive experiments for the identification of model parameters with an integrator or system-oriented view. Design/methodology/approach – At system design level, the actuation models need to reproduce with confidence the energy losses and the main dynamic effects. The adopted modelling methodology is based on non-intrusive measurements taken on a standard actuator test-bench. The actuator model is first structured with respect to the bond-graph formalism that allows a clear identification of the considered effects and associated causalities for model implementation. Various approaches are then combined, mixing blocked or moving load, position or torque control and time or frequency domains analysis. The friction representation model is suggested using a step-by-step approach that covers a wide domain of operation. The model is validated under varying torque and speed conditions. Findings – A structured model is introduced with support of the bond-graph formalism. Combining blocked/moving load and time/frequency domain experiments allows the development of progressive model identification. An advanced friction representation model is proposed including the effects of speed, transmitted force, quadrant of operation and roller-screw preload. Originality/value – Mechanical transmission energy losses and dynamics are modelled in a system-oriented view without massive need to confidential design parameters. Not only speed but also load and operation quadrant effects are reproduced by the proposed friction model. The non-intrusive experimental procedure is made consistent with use of a standard actuator test-bench.

Remote sensing satellites evaluation software (RSSE software) : Table of Contents

Mohammad Hassani, Mehran Mirshams — Sun Jun 14 14:15:06 BST 2009

Abstract:
Purpose – The purpose of this paper is to develop user friendly software with the minimum error and maximum performance in a form of remote sensing satellites evaluation software for estimation of weights and ranks of the remote sensing satellite plans, to decrease risk of management decisions. Design/methodology/approach – The analytic hierarchy process (AHP) as a comprehensive framework for strategic decision making is used to arrive at the weights of criteria and sub-criteria of remote sensing satellites. The Ms-Access software is written to compute the ranks of the remote sensing satellite plans based on the relative weights of inputs and then, the outputs from AHP are shown as a numerical graph and generates the Ms-Access database. Findings – One of the main objectives of this paper is an attempt to access this skill that compare several remote sensing satellite plans on quantity and quality point of view by several effective criteria such as mass, power consumption and cost of satellites, in addition to the remote sensing subsystem, communication subsystem, telemetry, tracking and control subsystem, attitude determination control subsystem and their own sub-criteria. Research limitations/implications – It is hard in just one paper, to gather lots of information about remote sensing satellite systems, use a new methodology that is unknown for aerospace engineering, and talk about an innovative software. Practical implications – This paper provides helpful evaluating software which has a data bank that it is very useful and impartial advice for space strategy's managing organization to compare several plans. Originality/value – This study provides low cost, time-saving, and high-performance remote sensing satellite evaluation software and gives valuable information and guidelines which help management decisions of aerospace organization.

Study on adaptability of GPS ionospheric error correction models : Table of Contents

Wang Xinlong, Li Yafeng — Sun Jun 14 14:15:06 BST 2009

Abstract:
Purpose – The purpose of this paper is to discuss the applicability of Global Positioning System (GPS) ionospheric delay correction models. Ionospheric delay is the most influential error source in GPS positioning, and ionospheric refraction is difficult to be corrected by dual frequency measurement for the common single frequency GPS receivers. Generally, ionospheric models are employed to correct errors. In order to analyze the ionospheric influence to GPS signals and the accuracy and adaptability of GPS ionospheric error correction models a quantificational analysis for ionospheric error correction models is absolutely necessary. Design/methodology/approach – On the base of the mechanism of ionospheric error, the Klobuchar model that is widely used and actual measured correction model (including local and global ionospheric error correction models) are analyzed in detail. With the data about ionosphere obtained from GPS authority Crustal Dynamics Data Information System, the precision and adaptability of two kinds of ionospheric error correction model are validated, and a predigested method of investigating precision of local ionospheric error correction model is presented. Findings – Klobuchar model has higher precision in middle or low latitude than in high latitude, and ionospheric delay fluctuates acutely in a day with a day-cycle. Ionospheric delay varies as the latitude changes: ionospheric delay is largest around equator and smallest in the areas of two poles, which shows symmetry. The relationship between ionospheric delay and longitude is similar to the relationship between ionospheric delay and latitude. The fitting model has better effect than Klobuchar model. Originality/value – This paper thoroughly researches GPS ionospheric error correction models. The conclusions are presented for the selection of GPS correction models, that it is useful for practical engineering application and will be the theoretic foundation for the improvement of the GPS accurate positioning.

Robust attitude acquisition for micro-satellite : Table of Contents

Weiyue Chen, Wuxing Jing — Sun Jun 14 14:15:06 BST 2009

Abstract:
Purpose – The purpose of this paper is to investigate the problem of the initial attitude detumbling and acquisition for micro-satellite using geomagnetism with the aid of the pitch momentum bias, and the application of the feedback linearization method, H8 and µ-synthesize control theory in the robust attitude acquisition controller design. Design/methodology/approach – The pitch flywheels establish the momentum bias state in the beginning of the detumbling stage and keep the momentum bias state thereafter. The geomagnetic change rate feedback detumbling controller is used to detumble the micro-satellite and the gyroscope rigidity is utilized to capture orbital negative normal orientation in the detumbling and attitude acquisition phase. Feedback linearization method is adopted to obtain the linear attitude dynamics. Based on the feedback linearization model, a quasi proportion differential (PD) controller is designed, meanwhile H8 and µ-synthesis control theories are adopted to synthesis the robust attitude acquisition controllers. Findings – The pitch momentum bias-aided attitude detumbling and acquisition method make the capture of the orbital negative normal orientation faster and more accurate than the classical initial operation process. Quasi PD and H8 have greater robustness than the classical PD attitude acquisition controller in normal geomagnetic case; quasi PD and µ-synthesis have greater robustness than the classical PD attitude acquisition controller in magnetic storm case. Originality/value – Provides pitch momentum bias-aided attitude detumbling and acquisition method for the micro-satellite and the robust attitude acquisition controller design technology.