Frequency Response Analysis for Dynamic Model Identification and Control of a Ducted Fan Aerial Vehicle in Hover

2013 ◽  
Vol 332 ◽  
pp. 56-61 ◽  
Author(s):  
Meysam Effati ◽  
Afshin Banazadeh
Keyword(s):  
Frequency Response ◽  
Dynamic Model ◽  
Transfer Functions ◽  
Complex Dynamics ◽  
Model Identification ◽  
Response Analysis ◽  
Ducted Fan ◽  
Power Spectral ◽  
Modern Engineering ◽  
Non Linear

System Identification is a key technology for the development and integration of modern engineering systems including unconventional flying vehicles. These systems are highly parametric with complex dynamics and nonlinearities. Ducted fans are special class of these vehicles that can take off vertically, hover and cruise at very low speed. In this paper, an exact equivalent linear system is found from the non-linear dynamic model of a ducted fan by use of frequency response identification. Here, power spectral density analysis is performed, using CIFER software, to evaluate the input-output responses in hover and to derive the transfer functions based on the coherence criterion. Then, PID controllers are designed by utilizing the identified transfer functions and the performance characteristics of the controllers are evaluated in fully non-linear simulation of the system.

Rotorcraft control response using linearised and non-linear flight dynamic models with different inflow models

2017 ◽  
Vol 121 (1238) ◽  
pp. 553-575 ◽  
Author(s):  
T. Sakthivel ◽  
C. Venkatesan
Keyword(s):  
Dynamic Model ◽  
Dynamic Models ◽  
Model Identification ◽  
Flight Test ◽  
Step Size ◽  
Response Characteristics ◽  
Wide Range ◽  
Non Linear ◽  
Steady Level ◽  
Control Response

ABSTRACTThe aim of the present study is to develop a relatively simple flight dynamic model which should have the ability to analyse trim, stability and response characteristics of a rotorcraft under various manoeuvring conditions. This study further addresses the influence of numerical aspects of perturbation step size in linearised model identification and integration timestep on non-linear model response. In addition, the effects of inflow models on the non-linear response are analysed. A new updated Drees inflow model is proposed in this study and the applicability of this model in rotorcraft flight dynamics is studied. It is noted that the updated Drees inflow model predicts the control response characteristics fairly close to control response characteristics obtained using dynamic inflow for a wide range of flight conditions such as hover, forward flight and recovery from steady level turn. A comparison is shown between flight test data, the control response obtained from the simple flight dynamic model, and the response obtained using a more detailed aeroelastic and flight dynamic model.

scholarly journals Omnidirectional Mobile Robot Dynamic Model Identification by NARX Neural Network and Stability Analysis Using the APLF Method

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1430
Author(s):  
Liang Xin ◽  
Yuchao Wang ◽  
Huixuan Fu
Keyword(s):  
Neural Network ◽  
Stability Analysis ◽  
Mobile Robot ◽  
Dynamic Model ◽  
Complex Dynamics ◽  
Model Identification ◽  
Theoretical Method ◽  
Omnidirectional Mobile Robot ◽  
Path Dependent ◽  
Narx Neural Network

In this paper, the NARX neural network system is used to identify the complex dynamics model of omnidirectional mobile robot while rotating with moving, and analyze its stability. When the mobile robot model rotates and moves at the same time, the dynamic model of the mobile robot is complex and there is motion coupling. The change of the model in different states is a kind of symmetry. In order to solve the problem that there is a big difference between the mechanism modeling motion simulation and the actual data, the dynamic model identification of mobile robot in special state based on NARX neural network is proposed, and the stability analysis method is given. To verify that the dynamic model of NARX identification is consistent with that of the mobile robot, the Activation Path-Dependent Lyapunov Function (APLF) algorithm is used to distinguish the NARX neural network model expressed by LDI. However, the APLF method needs to calculate a large number of LMIs in practice and takes a lot of time, and, to solve this problem, an optimized APLF method is proposed. The experimental results verify the effectiveness of the theoretical method.

scholarly journals Detection of Winding Axial Displacement of a Real Transformer by Frequency Response Analysis without Fingerprint Data

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 200
Author(s):  
Satoru Miyazaki
Keyword(s):  
Frequency Response ◽  
Transfer Functions ◽  
Axial Displacement ◽  
Lightning Strike ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Transmission Tower ◽  
Three Phase ◽  
Transformer Winding ◽  
Fingerprint Data

Detection of the axial displacement of power-transformer winding is important to ensure its highly reliable operation. Frequency response analysis is a promising candidate in detecting the axial displacement. However, a method of detecting the axial displacement at an incipient stage without the need for fingerprint data has not been investigated yet. This paper focuses on resonances showing a bipolar signature in the transfer function of inductive interwinding measurement, which is sensitive to the axial displacement of the winding. Transfer functions in the inductive interwinding measurements of eight power transformers are measured before shipping to elucidate the features of resonances showing a bipolar signature. The measured resonances showing the bipolar signature can be divided into the “stair type” and the “crossing-curve type”. It is found that the grounding points in an inductive interwinding measurement determine the type of resonance showing the bipolar signature, irrespective of the type of winding, such as interleaved or multilayer winding, the winding arrangement, and the existence of stabilizing and tertiary windings. On the basis of this finding, a method of detecting the axial displacement of a transformer winding is proposed. In the proposed method, the amplitudes of the resonances among three phases are compared, or the three-phase pattern of the resonances is compared with normal patterns. Therefore, the proposed method is applicable to three-phase transformers without fingerprint data. The proposed method is applied to a real transformer that experienced a ground fault due to a lightning strike at a nearby transmission tower, and the effectiveness of the proposed method is confirmed.

scholarly journals Parametrical Synthesis of Radio Devices with the Set Quantity of Identical Cascades for Inclusion Variants of Jet Two-port Networks between a Nonlinear Part and Loading

2021 ◽  
Vol 24 (6) ◽  
pp. 27-37
Author(s):  
A. A. Golovkov ◽  
A. V. Fomin
Keyword(s):  
Frequency Response ◽  
Numerical Optimization ◽  
Transfer Functions ◽  
Optimization Methods ◽  
Frequency Characteristics ◽  
Algebraic Equations ◽  
Nonlinear Part ◽  
Non Linear ◽  
Microwave Control ◽  
Voltage Feedback

Introduction. The ability to analytically determine some parameters of various radio devices, which are optimal according to the criterion of providing the set values of the modules and phases of transfer functions at the required number of frequencies, significantly reduces the time for numerical optimization of the rest of the parameters according to the criterion of forming the required frequency response and frequency response in the frequency band. Until now, such problems with respect to radio devices have been solved only for one stage of the "nonlinear part – matching device" or "matching device – nonlinear part" type. As a matching device, reactive, resistive, complex, or mixed quad-poles were used.Aim. Development of algorithms for parametric synthesis of radio devices with an arbitrary number of identical cascades of the "nonlinear part – matching reactive quadrupole" type according to the criterion of ensuring the specified frequency characteristics. Non-linear parts are represented as a non-linear element and parallel or serial current or voltage feedback.Materials and methods. Four-pole theory, matrix algebra, decomposition method, method of synthesis of microwave control devices, numerical optimization methods.Results. Systems of algebraic equations are formed and solved. Models of optimal quadrupole conductors are obtained in the form of mathematical expressions for determining the relationships between the elements of their classical transmission matrix and for finding the frequency dependences of the resistances of two-pole conductors.Conclusion. It is shown that the frequency characteristics of the studied radio devices from the same stages are identical or similar to the frequency characteristics of radio devices from the same stage, but with the signal source and load resistances changed in a certain way. Such schemes are called equivalent. A comparative analysis of the theoretical results (frequency response and frequency response of radio devices) obtained by mathematical modeling in the "MathCad" system, and the experimental results obtained by circuit modeling in the "OrCAD" and "MicroCap" systems, shows their satisfactory agreement.

Amplitude Frequency Response Analysis and Synthesis of Unfactored Transfer Functions

1964 ◽  
Vol 86 (1) ◽  
pp. 32-36 ◽  
Author(s):  
J. S. Ausman
Keyword(s):  
Frequency Response ◽  
Transfer Functions ◽  
Response Characteristic ◽  
System Stability ◽  
System Response ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Response Curves ◽  
Analysis And Synthesis ◽  
Amplitude Versus

A graphical method provides, without templates and without factoring, a means for rapidly estimating log-amplitude versus log-frequency response curves from transfer functions in their unfactored polynomial form. The technique can also be used to design or synthesize transfer functions which will produce a specified frequency response characteristic. Included is a graphical stability criterion for third and fourth-order systems which provides a quick check on system stability during the course of design or of analysis of the system response.

Sign in / Sign up

Export Citation Format

Share Document