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Showing 1 to 20 of 38 for “"Describing Function"”.
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Describing Function Analysis for Nonlinear Sampled-Data Control Systems
Made available in DSpace on 2014-12-08T22:23:48Z (GMT). No. of bitstreams: 1 6511822.pdf: 5220525 bytes, checksum: 8a3d98e38565fcb255aa8e93fd683569 (MD5) Previous issue date: 1965
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Robustness of adaptive control systems to unmodeled dynamics : a describing function viewpoint
… albeit approximate, is to use the well-known Describing Function (DF) method. In doing so, the analysis of the robust adaptive control problem becomes tractable and resembles that of familiar and classical linear stability analysis.
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Extended describing function method for small-signal modeling of resonant and multi-resonant converters
The extended describing function method is proposed as a systematic small-signal modeling approach to nonlinear switching circuits. This method offers significant simplification upon the previous work on using the multi-variable describing functions to treat the circuit nonlinearities. As an …
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Limit Cycle PIO Analysis With Simultaneously Acting Multiple Asymmetric Saturation
… These analyses involve the use of dual input describing functions which enable the prediction of frequency, amplitude, and mean point of oscillation.
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Development of Reduced-Order Flame Models for Prediction of Combustion Instability
… generalized Galerkin method. In addition, the describing function for the flame was measured experimentally and used to identify an empirical nonlinear flame model. Furthermore, a linear acoustic model was developed and identified for the Rijke tube experiment. Closed-loop thermoacoustic …
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Existence and stability analysis of ferroresonance using the generalized state-space averaging technique
… models. The theory of the incremental-input describing function is revisited and a subtle flaw in the formulation of the theory is modified to address the stability of general systems, particularly at synchronous frequency. A generalized Nyquist criterion is presented to assess the stability …
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Fractional Order Identification Method and Control: Development of Control for Non-Minimum Phase Fractional Order System
… dc-dc converter operation by use of a modified describing function technique. Results are presented by comparing a conventional linearization technique (i.e., integer-order transfer functions) to the describing-function derived equivalent fractional-order model. The benefits of this approach in …
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Nonlinear analysis of eddy-current couplings in feedback control systems
… control systems. The analysis makes use of the describing function method to predict transient response. Effects of the nonlinearity are discussed and backed with an analog computer study. Conclusions arrived at show the absquare nonlinearity to be advantageous under conditions of zero steady …
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Nonlinear thermoacoustic oscillations of a ducted laminar premixed flame
… These criteria, along with the flame describing function, are used to find the types of bifurcation and minimum triggering amplitudes. The choice of model for the velocity perturbation field around the flame is shown to have a strong influence on the types of bifurcation in the system. …
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Representing systems through object-process methodology and axiomatic design
… Methodology is used to improve formulation of Functional Requirements and Design Parameters in Axiomatic Design. Examples demonstrate that adequate descriptions of both function and architecture require a combination of objects and processes. Object- Process Methodology templates for describing …
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Dynamic Performance Analyses of Current Sharing Control for DC/DC Converters
… concept is expanded in the form of extended describing function, so that the terminal characteristics of paralleled converters are represented by a series of impedances. Besides the analyses, this work also proposed several solutions for the beat-frequency oscillation issue which are …
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Modelling and analysis of nonlinear thermoacoustic systems using frequency and time domain methods
… developed: the first, called Flame Double Input Describing Function (FDIDF), is an extension of the Flame Describing Function (FDF). The FDIDF approximates the flame nonlinear response when it is forced simultaneously with two frequencies, whereas the FDF is limited to one frequency. Although …
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Forcing of globally unstable jets and flames
… however, cannot be detected in the flame describing function. That is because the flame describing function captures the response at only the forcing frequency and ignores all other frequencies, most notably those arising from the natural mode and from its interactions with the forcing. …
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Investigation of an optimalising controller
… the deactive time is derived. Utilising describing function techniques, the steady-state response of the control system is predicted and the results are shown to be in good agreement with the experimental results. The adaptive response of the system is investigated and it is shown that …
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Digital processing of system responses
… comparison is made between the crosscorrelation function and fast Fourier transform methods of mechanisation, by comparing modelling estimates given by both procedures for different system conditions.<br/><br/>The application of the technique to nonlinear systems has shown. however, the procedure …
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Analysis and feedback control of magnetic bearings with reference to flywheel energy storage.
… magnetic components is derived. Subsequently describing functions characterising the small- as well as large signal behaviour of the same bearing in the "voltage driven" mode, are obtained. It is shown that workable results are obtained for most practical situations by using linear systems …
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Suppression of limit cycle oscillations in an aeroelastic system using robust and adaptive control
… with pitch structural nonlinearity using the describing function method is determined. The model includes unsteady aerodynamics based on Theodorsen's theory. The dual-input describing functions of the nonlinearity are used for the limit cycle analysis. Interestingly it is found that flutter …
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Equivalent Circuit Model for Current Mode Controls and Its Extensions
… architectures. However, the model was derived by describing function method, which is very arithmetically complicated, not to mention time consuming. For the analysis and design of non-linear system, equivalent circuit model, which is user friendly and intuitive, is an effective tool. In this …
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Investigation of slow oscillations in blood pressure
… of a diagnostic test of cardiovascular dysfunction or disease. Due to this hypothesis, extensive effort has been invested in measuring the strength of this slow oscillation in blood pressure in a range of physiological and pathophysiological conditions. However, the momentum of this …
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