scholarly journals Parametric Identification of Chaotic Base-Excited Double Pendulum Experiment

2004 ◽  
Author(s):  
Yang Liang ◽  
B. F. Feeny
Keyword(s):  
Harmonic Balance ◽  
Parametric Identification ◽  
Identification Algorithm ◽  
Double Pendulum ◽  
Unstable Periodic Orbits ◽  
Identification Process ◽  
Response Data ◽  
Regression Techniques ◽  
Linearized System ◽  
Pendulum Experiment

An improved parametric identification of chaotic systems was investigated for a double pendulum. From recorded experimental response data, the unstable periodic orbits were extracted and later used in a harmonic balance identification process. By applying digital filtering, digital differentiation and linear regression techniques for optimization, the results were improved. Verification of the related simulation system and linearized system also corroborated the success of the identification algorithm.

Parametric Identification of Chaotic Systems Via a Long-Period Harmonic Balance

2005 ◽  
Author(s):  
Yang Liang ◽  
B. F. Feeny
Keyword(s):  
Harmonic Balance ◽  
Chaotic Systems ◽  
Harmonic Balance Method ◽  
Parametric Identification ◽  
Model Parameters ◽  
Unstable Periodic Orbits ◽  
Ideal Model ◽  
Domain Identification ◽  
Long Period ◽  
Countable Infinity

Hyperbolic chaotic sets are composed of a countable infinity of unstable periodic orbits (UPOs). Symbol dynamics reveals that any long chaotic segment can be approximated by a UPO, which is a periodic solution to an ideal model of the system. Treated as such, the harmonic balance method is applied to the long chaotic segments to identify model parameters. Ultimately, this becomes a frequency domain identification method applied to chaotic systems.

Parametric Identification of an Experimental Two-Well Oscillator

1999 ◽  
Author(s):  
B. F. Feeny ◽  
C.-M. Yuan
Keyword(s):  
Periodic Orbits ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Parametric Identification ◽  
Equation Model ◽  
Unknown Parameters ◽  
Differential Equation Model ◽  
Identification Process ◽  
Nonlinear Force ◽  
Force Displacement

Abstract The identification of parameters in an experimental two-well chaotic system is presented. The method involves the extraction of periodic orbits from a chaotic set. The form of the differential-equation model is assumed, with unknown coefficients on the terms in the model. The harmonic-balance method is applied to these periodic orbits, resulting in a linear equation in the unknown parameters, which can then be solved in the least-squares sense. The identification process reveals the nonlinear force-displacement characteristic of the oscillator. The results are cross-checked with various sets of extracted periodic orbits. The model is validated by examining simulated responses.

Identification of Circulating Fluidized Bed Boiler Bed Temperature Based on Hyper-Plane-Shaped Fuzzy C-Regression Model

2020 ◽  
Vol 19 (04) ◽  
pp. 2050029
Author(s):  
Jianzhong Shi
Keyword(s):  
Regression Model ◽  
Fluidized Bed ◽  
Membership Function ◽  
Clustering Algorithm ◽  
Circulating Fluidized Bed ◽  
Fuzzy Model ◽  
Identification Algorithm ◽  
Identification Process ◽  
Bed Temperature ◽  
Hyper Plane

Bed temperature in dense-phase zone is the key parameter of circulating fluidized bed (CFB) boiler for stable combustion and economic operation. It is difficult to establish an accurate bed temperature model as the complexity of circulating fluidized bed combustion system. T-S fuzzy model was widely applied in the system identification for it can approximate complex nonlinear system with high accuracy. Fuzzy c-regression model (FCRM) clustering based on hyper-plane-shaped distance has the advantages in describing T-S fuzzy model, and Gaussian function was adapted in antecedent membership function of T-S fuzzy model. However, Gaussian fuzzy membership function was more suitable for clustering algorithm using point to point distance, such as fuzzy c-means (FCM). In this paper, a hyper-plane-shaped FCRM clustering algorithm for T-S fuzzy model identification algorithm is proposed. The antecedent membership function of proposed identification algorithm is defined by a hyper-plane-shaped membership function and an improved fuzzy partition method is applied. To illustrate the efficiency of the proposed identification algorithm, the algorithm is applied in four nonlinear systems which shows higher identification accuracy and simplified identification process. At last, the algorithm is used in a circulating fluidized bed boiler bed temperature identification process, and gets better identification result.

Robust Control-Oriented Modeling of a Feedback-Linearized Powered Pediatric Lower-Limb Orthosis

2019 ◽  
Author(s):  
Curt A. Laubscher ◽  
Jerzy T. Sawicki
Keyword(s):  
Robust Control ◽  
Lower Limb ◽  
Feedback Linearization ◽  
Performance Criteria ◽  
Model Uncertainties ◽  
Control Techniques ◽  
Response Data ◽  
Modeling Uncertainties ◽  
Recorded Data ◽  
Linearized System

Abstract Linear robust control techniques such as μ-synthesis can be used to design controllers for linear systems to guarantee specified performance criteria in the presence of modeling uncertainties, disturbances, and sensor noise. However, these techniques are rather uncommon in robotics due to the nonlinear nature of the plant where direct application would require large model uncertainties and therefore may only create a satisfactory controller if using lenient performance criteria. The inclusion of feedback linearization can rectify this by effectively converting the plant from a nonlinear system to a linear one, resulting in smaller model uncertainties. This paper proposes the use of feedback linearization to enable the use of linear robust control techniques on nonlinear systems. This approach is applied to a provisional version of a powered pediatric lower-limb orthosis. Sine sweep experiments are conducted to determine frequency response data for the system with and without feedback linearization. Models are identified to match the recorded data using optimization for both cases. Uncertainties are manually applied such that they encapsulate the observed measurements. The amount of uncertainties in the two models are quantified and a comparison shows that the uncertainties in the feedback-linearized system are smaller than in the system without feedback linearization.

scholarly journals Parametric identification algorithm for asynchronous electric motor inverter on the switching intervals of power transistors

2019 ◽  
Vol 124 ◽  
pp. 02017
Author(s):  
A. Andreev ◽  
M. Andreev ◽  
D. Kolesnihenko ◽  
R.R. Dyganova ◽  
G.T. Merzadinova ◽  
...  
Keyword(s):  
Real Time ◽  
Electric Drive ◽  
Electric Motor ◽  
Parametric Identification ◽  
Identification Algorithm ◽  
Power Transistors ◽  
Asynchronous Electric Drive ◽  
Subsequent Calculation ◽  
Asynchronous Electric Motor ◽  
A Current

The authors propose an algorithm for identifying the parameters of a controlled asynchronous electric drive in real time, which provides calculation of stator and rotor resistances which change as a function of temperature. The algorithm is based on the analysis of a current tube of electric motor phase with the subsequent calculation of resistances.

scholarly journals Estimation of Squeeze-Film Damping and Inertial Coefficients from Experimental Free-Decay Data

1986 ◽  
Vol 200 (2) ◽  
pp. 123-133 ◽  
Author(s):  
J B Roberts ◽  
R Holmes ◽  
P J Mason
Keyword(s):  
Linear Model ◽  
Transient Response ◽  
Parametric Identification ◽  
Squeeze Film ◽  
Decay Data ◽  
Operating Range ◽  
Response Data ◽  
Squeeze Film Damping ◽  
Free Decay ◽  
Theoretical Predictions

This paper describes the results obtained from an experimental programme concerned with a parametric identification of the damping and inertial coefficients of a cylindrical squeeze-film bearing, through an analysis of transient response data. The results enable the operating range for which a linear model of the squeeze-film is appropriate to be determined. Comparisons are made between the estimated coefficients and theoretical predictions.

scholarly journals Control-Based Continuation of Unstable Periodic Orbits

2009 ◽  
Author(s):  
Jan Sieber ◽  
Bernd Krauskopf ◽  
David Wagg ◽  
Simon Neild ◽  
Alicia Gonzalez-Buelga
Keyword(s):  
Periodic Orbits ◽  
Control Parameter ◽  
Unstable Periodic Orbits ◽  
Saddle Node Bifurcation ◽  
Experimental Procedure ◽  
Stable Period ◽  
Fold Bifurcation ◽  
Time Delayed Feedback ◽  
Unstable Branch ◽  
Pendulum Experiment

We present an experimental procedure to track periodic orbits through a fold (saddle-node) bifurcation, and demonstrate it with a parametrically excited pendulum experiment where the control parameter is the amplitude of the excitation. Specifically, we track the initially stable period-one rotation of the pendulum through its fold bifurcation and along the unstable branch. The fold bifurcation itself corresponds physically to the minimal amplitude that is able to support sustained rotation. Our scheme is based on a modification of time-delayed feedback in a continuation setting, and we show for an idealized model that it converges with the same efficiency as classical proportional-plus-derivative control.

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