Topic
Describing function
About: Describing function is a research topic. Over the lifetime, 1742 publications have been published within this topic receiving 26702 citations.
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12 Aug 1996
TL;DR: In this paper, a method to analyse the synchronized microwave oscillators is first developed by use of Volterra Series expansion, and general expressions of calculating responses in harmonic loops are obtained.
Abstract: A method to analyse the synchronized microwave oscillators is first developed by use of Volterra Series expansion. The general expressions of calculating responses in harmonic loops are obtained. Some cases such as the frequency divider and doubler are discussed in details. The results show that this method is simpler and can get higher accuracy than the describing function and harmonic balance method, and that it is more efficient than the averaging method.
27 Jun 2012
TL;DR: This paper provides necessary conditions for the existence of self sustaining periodic oscillations in such interval plants, and indicates a possible design algorithm to avoid such periodic solutions or limit cycles.
Abstract: In several systems, the physical parameters of the system vary over time or operating points. A popular way of representing such plants with structured or parametric uncertainties is by means of interval polynomials. However, ensuring the stability of such systems is a robust control problem. Fortunately, Kharitonov's theorem enables the analysis of such interval plants and also provides tools for design of robust controllers in such cases. The present paper considers one such case, where the interval plant is connected with a timeinvariant, static, odd, sector type nonlinearity in its feedback path. This paper provides necessary conditions for the existence of self sustaining periodic oscillations in such interval plants, and indicates a possible design algorithm to avoid such periodic solutions or limit cycles. The describing function technique is used to approximate the nonlinearity and subsequently arrive at the results. Furthermore, the value set approach, along with Mikhailov conditions, are resorted to in providing graphical techniques for the derivation of the conditions and subsequent design algorithm of the controller.
03 Apr 2022-Proceedings Of The Institution Of Mechanical Engineers, Part I: Journal Of Systems And Control Engineering
TL;DR: In this article , a Bernstein polynomials based compensator is proposed to attenuate the degrading effect of saturation nonlinearities in process control applications, where a frequency dependent cost function is utilized in order to calculate the optimal coefficients for the proposed compensator.
Abstract: This study deals with the design of Bernstein polynomials based compensator in order to attenuate the degrading effect of saturation nonlinearities in process control applications. The proposed compensator is structured in terms of Bernstein polynomials and a frequency dependent cost function is utilized in order to calculate the optimal coefficients for the proposed compensator. In order to illustrate the efficiency of proposed compensator, a well-known benchmark process control problem, the coupled tank system, is taken into consideration in this study. The success of the proposed compensator is illustrated via frequency based harmonic plots and time domain plots of saturated control signal.
TL;DR: In this paper , a limited amplitude-disturbance observer (LADOB) is proposed to counteract transient disturbance dynamics in a nonlinear control system with backlash, which directly constrains the linear output amplitude of the observer using a saturation function.
Abstract: This paper presents a limited amplitude-disturbance observer (LADOB) as a means to counteract transient disturbance dynamics in a nonlinear control system with backlash. The core principle of this method involves directly constraining the linear output amplitude of the observer using a saturation function. This approach yields a high-bandwidth disturbance observer while ensuring the stability. By virtue of its rapid response, the LADOB effectively mitigates backlash spikes induced by speed reversal. Additionally, the saturation function within the LADOB control system addresses limit cycle oscillations stemming from backlash dynamics. An investigation is conducted to determine the optimal balance between stability and anti-disturbance performance by examining the relationship between the saturation threshold and the system's bandwidth. Experimental validation is carried out on a belt-drive turntable, effectively demonstrating the efficacy of the proposed method in attenuating nonlinear backlash.
17 Oct 2022
TL;DR: In this paper , the authors presented a detail dynamic modeling, small-signal analysis, controller design and its stability assessment of non-ideal Sheppard-Taylor DC-DC converters.
Abstract: This paper presents a detail dynamic modeling, small-signal analysis, controller design and its stability assessment of non-ideal Sheppard-Taylor DC-DC converters. This class of DC-DC converter provides non-pulsing input and output current via two inductors at the input and output sides with improved current ripple. This paper provides the detail small-signal analysis that can be used as a systematic guideline for designing a robust control system for this class of DC-DC converters, which is a missing piece of the puzzle within the literature. The state space model and the canonical model of the system are also provided. Furthermore, the open loop line-to-output transfer function and control-to-output (open loop and closed loop) for non-ideal Sheppard-Taylor DC-DC converter are derived and used for developing a PID-based compensator to validate the derived models. The provided analysis is supported with simulation studies to validate the theoretical derivations.