scholarly journals Fuzzy Logic-Based Aerodynamic Modeling with Continuous Differentiability

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Ray C. Chang
Keyword(s):  
Fuzzy Logic ◽  
Atmospheric Turbulence ◽  
Model Development ◽  
Unsteady Aerodynamics ◽  
Least Square Method ◽  
Least Square ◽  
Transport Aircraft ◽  
Fuzzy Logic Algorithm ◽  
Modeling Process ◽  
Data Points

This paper presents a modeling method based on a fuzzy-logic algorithm to establish aerodynamic models by using the datasets from flight data recorder (FDR). The fuzzy-logic aerodynamic models are utilized to estimate more accurately the nonlinear unsteady aerodynamics for a transport aircraft, including the effects of atmospheric turbulence. The main objective in this paper is to present the model development and the resulting models with continuous differentiability. The uncertainty and correlation of the data points are estimated and improved by monitoring a multivariable correlation coefficient in the modeling process. The latter is increased by applying a least square method to a set of data points to train a set of modeling coefficients. A commercial transport aircraft encountered severe atmospheric turbulence twice at transonic flight in descending phase is the study case in the present paper. The robustness and nonlinear interpolation capability of the fuzzy-logic algorithm are demonstrated in predicting the degradation in performance and stability characteristics of this transport in severe atmospheric turbulence with sudden plunging motion.

scholarly journals Quantitative Assessment of Dynamic Stability Characteristics for Jet Transport in Sudden Plunging Motion

2021 ◽  
Author(s):  
Yonghu Wang ◽  
Ray C. Chang ◽  
Wei Jiang
Keyword(s):  
Fuzzy Logic ◽  
Dynamic Stability ◽  
Quantitative Assessment ◽  
Normal Load ◽  
Unsteady Aerodynamics ◽  
Assessment Method ◽  
Load Factor ◽  
Gravitational Acceleration ◽  
Transport Aircraft ◽  
Motion Modes

Abstract The main objective of this article is to present a training program of loss control prevention for the airlines to enhance aviation safety and operational efficiency. The assessments of dynamic stability characteristics based on the approaches of oscillatory motion and eigenvalue motion modes for jet transport aircraft response to sudden plunging motions are demonstrated in this article. A twin-jet transport aircraft encountering severe clear-air turbulence in transonic flight during the descending phase will be examined as the study case. The flight results in sudden plunging motions with abrupt changes in attitude and gravitational acceleration (i.e. the normal load factor). Development of the required thrust and aerodynamic models with the flight data mining and the fuzzy-logic modeling techniques will be presented. The oscillatory derivatives extracted from these aerodynamic models are then used in the study of variations in stability characteristics during the sudden plunging motion. The fuzzy-logic aerodynamic models are utilized to estimate the nonlinear unsteady aerodynamics while performing numerical integration of flight dynamic equations. The eigenvalues of all motion modes are obtained during time integration. The present quantitative assessment method is an innovation to examine possible mitigation concepts of accident prevention and promote the understanding of aerodynamic responses of the jet transport aircraft.

scholarly journals Structural Health Monitoring of Transport Aircraft with Fuzzy Logic Modeling

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Ray C. Chang ◽  
C. Edward Lan
Keyword(s):  
Fuzzy Logic ◽  
Structural Health Monitoring ◽  
Atmospheric Turbulence ◽  
Health Monitoring ◽  
Structural Flexibility ◽  
Monitoring Method ◽  
Logic Modeling ◽  
Transport Aircraft ◽  
Structural Health ◽  
Static Aeroelasticity

A structural health monitoring method based on the concept of static aeroelasticity is presented in this paper. This paper focuses on the estimation of these aeroelastic effects on older transport aircraft, in particular the structural components that are most affected, in severe atmospheric turbulence. Because the structural flexibility properties are mostly unknown to aircraft operators, only the trend, not the magnitude, of these effects is estimated. For this purpose, one useful concept in static aeroelastic effects for conventional aircraft structures is that under aeroelastic deformation the aerodynamic center should move aft. This concept is applied in the present paper by using the fuzzy-logic aerodynamic models. A twin-jet transport aircraft in severe atmospheric turbulence involving plunging motion is examined. It is found that the pitching moment derivatives in cruise with moderate to severe turbulence in transonic flight indicate some degree of abnormality in the stabilizer (i.e., the horizontal tail). Therefore, the horizontal tail is the most severely affected structural component of the aircraft probably caused by vibration under the dynamic loads induced by turbulence.

scholarly journals Pengaruh Masukan Kendali Terhadap Hasil Identifikasi Parameter Pesawat Udara Konfigurasi Konvensional Matra Terbang Longitudinal

2019 ◽  
Vol 7 (1) ◽  
pp. 25-30
Author(s):  
Eries Bagita Jayanti ◽  
Novita Atmasari ◽  
Hidayati Mardikasari ◽  
Ardian Rizaldi ◽  
Fuad Surastyo Pranoto ◽  
...  
Keyword(s):  
Parameter Identification ◽  
Least Square Method ◽  
Least Square ◽  
Model Parameters ◽  
Control Field ◽  
Longitudinal Dimension ◽  
Navigation Data ◽  
Modeling Process ◽  
High Level ◽  
Input Form

Parameter identification is a process to get real characteristics of the motion dynamics of an object which can then be used to build the dynamics model of the object, which has a very high level of validity and accuracy. The modeling process is usually carried out using aircraft input data and the results of existing navigation data recording. From the data, the model parameters are estimated using the simple least square method. In this study, the simulation was carried out by varying the deflection input in the control field and simulation time. The input given to the longitudinal dimension is the deflection of the elevator control field. The results of parameter identification in the Corsair A-7A plane in the longitudinal dimension indicate that the input form 3-2-1 has a smaller error value than using doublet and pulse inputs. This shows that the input form 3-2-1 is most suitable for the longitudinal dimension among the given inputs.

Modeling and Controller Design for a Coupled–Tank Liquid Level System: Analysis & Comparison

2012 ◽  
Author(s):  
Mohd Fua’ad Rahmat ◽  
Sahazati Md Rozali
Keyword(s):  
Fuzzy Logic ◽  
System Identification ◽  
System Analysis ◽  
Binary Sequence ◽  
Least Square Method ◽  
Least Square ◽  
Step Response ◽  
Response Analysis ◽  
Pseudorandom Binary Sequence ◽  
Tank System

Sistem yang diuji ialah tangki berkembar yang biasa digunakan dalam proses kawalan industri. Prinsip asas sistem tangki berkembar adalah untuk mengekalkan paras cecair di dalam tangki pada suatu nilai tetap apabila wujud aliran keluar masuk cecair dalam tangki. Analisis tindak balas langkah, analisis pseudorandom binary sequence (PRBS) dan kaedah least square digunakan untuk mengklasifikasikan sistem ini. Objektif utama projek ini adalah untuk menentukan model matematik sistem tangki berkembar menggunakan tiga teknik tesebut. Ia diikuti dengan mereka bentuk pengawal yang terdiri daripada pengawal PID dan pengawal Fuzzy Logic untuk sistem ini. Pada peringkat akhir projek ini, penggunaan kedua-dua pengawal dalam aplikasi industri dibandingkan dan dianalisa. Kata kunci: Pengenalpastian sistem, tindak balas langkah, pseudorandom binary sequence, kaedah least square, pengawal Fuzzy Logic & PID The system under investigation is a coupled-tank apparatus which is a laboratory bench top emulation of a common process in industrial control. The basic control principle of the coupled-tank system is to maintain a constant level of the liquid in the tank when there is an inflow and outflow of water in the tank and outflow of water out of the tank respectively. Classification of this system using system identification technique involved the transient response analysis, the pseudorandom binary sequence (PRBS) analysis and the least square method. The main objective of this project is to determine the mathematical model of a coupled-tank system using these techniques. It follows by designing a controller consists of a PID and a Fuzzy Logic controllers for the system. At the final stage of this project, the usage of both controllers in industrial applications is compared and analyzed. Key words: System identification, step response, pseudorandom binary sequence, least square method, PID & Fuzzy Logic controller

Estimation of Weibull parameter with a modified weight function

1997 ◽  
Vol 12 (10) ◽  
pp. 2638-2642 ◽  
Author(s):  
B. K. Chandrasekhar
Keyword(s):  
Weight Function ◽  
Weibull Modulus ◽  
Least Square Method ◽  
Probability Of Failure ◽  
Strength Distribution ◽  
Least Square ◽  
Weight Functions ◽  
Distribution Data ◽  
Ceramic Components ◽  
Data Points

The Weibull modulus is widely used for estimating the reliability of ceramic components in engineering applications. An improvement in the evaluation of the Weibull modulus is achieved by using an appropriate weight function to the data points while fitting a straight line to the Weibull plot by the least square method. The conventional weight function is a function of the probability of failure. This paper describes an alternate method of obtaining the weight function based on first principles. This modified weight function is a function of the stress at failure rather than probability of failure. Evaluation of the two-parameter Weibull modulus was estimated on simulated strength distribution data with both the weight functions. A comparative analysis indicates that the modified weight function gives a different result than the conventional weight function. The paper also highlights the effect and importance of uncertainties in the measurement of strength on the calculated Weibull modulus.

Direct Assessment of Effective Renal Plasma Flow from Renoscintigraphy with a Gamma Camera and an On-Line Computer

1981 ◽  
Vol 20 (06) ◽  
pp. 274-278
Author(s):  
J. Liniecki ◽  
J. Bialobrzeski ◽  
Ewa Mlodkowska ◽  
M. J. Surma
Keyword(s):  
Count Rate ◽  
Renal Plasma Flow ◽  
Early Period ◽  
Least Square Method ◽  
Least Square ◽  
Uptake Coefficient ◽  
Positive Linear Correlation ◽  
On Line ◽  
Best Fit ◽  
Plasma Activity

A concept of a kidney uptake coefficient (UC) of 131I-o-hippurate was developed by analogy from the corresponding kidney clearance of blood plasma in the early period after injection of the hippurate. The UC for each kidney was defined as the count-rate over its ROI at a time shorter than the peak in the renoscintigraphic curve divided by the integral of the count-rate curve over the "blood"-ROI. A procedure for normalization of both curves against each other was also developed. The total kidney clearance of the hippurate was determined from the function of plasma activity concentration vs. time after a single injection; the determinations were made at 5, 10, 15, 20, 30, 45, 60, 75 and 90 min after intravenous administration of 131I-o-hippurate and the best-fit curve was obtained by means of the least-square method. When the UC was related to the absolute value of the clearance a positive linear correlation was found (r = 0.922, ρ > 0.99). Using this regression equation the clearance could be estimated in reverse from the uptake coefficient calculated solely on the basis of the renoscintigraphic curves without blood sampling. The errors of the estimate are compatible with the requirement of a fast appraisal of renal function for purposes of clinical diagknosis.

PENGARUH KNOWLEDGE MANAGEMENT, KOMPETENSI, MOTIVASI TERHADAP KINERJA KARYAWAN

2015 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Miftahol Arifin
Keyword(s):  
Knowledge Management ◽  
Linear Regression ◽  
Significant Influence ◽  
Employee Performance ◽  
Least Square Method ◽  
Least Square ◽  
Analysis Tool ◽  
Ordinary Least Square ◽  
Competence Motivation ◽  
Performance Analyze

The purpose of this research is to analyze the influence of knowledge management on employee performance, analyze the effect of competence on employee performance, analyze the influence of motivation on employee performance). In this study, samples taken are structural employees PT.centris Kingdom Taxi Yogyakarta. The analysis tool in this study using multiple linear regression with Ordinary Least Square method (OLS). The conclusion of this study showed that the variables of knowledge management has a significant influence on employee performance, competence variables have an influence on employee performance, motivation variables have an influence on employee performance, The analysis showed that the variables of knowledge management, competence, motivation on employee performance.Keywords: knowledge management, competence, motivation, employee performance.

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