Topic
Describing function
About: Describing function is a research topic. Over the lifetime, 1742 publications have been published within this topic receiving 26702 citations.
Papers published on a yearly basis
Papers
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TL;DR: In this article, the authors present a systematic yet simple procedure for tuning the Super-Twisting (STW) algorithm parameters in order to obtain pre-specified frequency and magnitude of the resulting chattering oscillation.
10 citations
28 Feb 1970
TL;DR: In this paper, an experimental investigation was carried out of the'remnant' portion of the mathematical model of the human operator, which consists of the combination of a quasilinear describing function and a remnant term.
Abstract: : An experimental investigation was carried out of the 'remnant' portion of the mathematical model of the human operator. This model consists of the combination of a quasilinear describing function and a remnant term. A single-axis tracking task, with random forcing functions and a compensatory display, was used to investigate the effect of the type of manipulator and the bandwidth of the forcing function on the remnant. Pressure and free-moving manipulator were employed with rate-control vehicle dynamics and filtered-white-noise forcing functions similar in spectral shape to those used in previous work. Data is presented which show the effects of the manipulator and of the forcing function on the describing function, on the performance measures of the system and on the power spectrum and the amplitude probability distribution of the remnant. (Author)
10 citations
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TL;DR: In this article, an autonomous single-loop feedback system where the nonlinear element is assumed to be a continuous bounded function is considered and sufficient conditions are obtained for the existence and nonexistence of an oscillation of the system in terms of the describing function criterion.
Abstract: We consider an autonomous single-loop feedback system where the nonlinear element is assumed to be a continuous bounded function. Sufficient conditions are obtained for the existence and nonexistence of an oscillation of the system in terms of the describing function criterion. In addition to the qualitative existence results, error bounds on some pertinent oscillation parameters are computed. A graphical procedure is developed to aid in the application of these results.
10 citations
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TL;DR: In this article, the performance of the acceleration feedback control is compared with that of the simple passive vibration absorber and the effect of time-delay in the feedback loop is also investigated.
Abstract: Vortex-induced vibration is a common phenomenon observed in many engineering applications and it is detrimental to the performances and health of the system. It is, therefore, imperative for engineers to make suitable design modifications or arrange for some type of control device to mitigate such oscillations. In this paper, the performance of the acceleration feedback control is compared with that of the simple passive vibration absorber. The effect of time-delay in the feedback loop is also investigated. The acceleration of the primary system is measured and passed through a second-order compensator. The active absorber is designed by setting the filter frequency same as the natural frequency of vibration and the optimum filter damping is numerically obtained. Nonlinear analysis is performed using the Describing Function method and the results are validated using direct numerical simulation performed in MATLAB Simulink. In the present paper, vortex shedding frequencies are selected from two different regions, one with vortex shedding frequency less than the natural frequency of the system and other having vortex shedding frequency higher than the natural frequency of the system. It is observed that the acceleration feedback control can effectively reduce the amplitude of vibration to a great extent. It is also observed that the amplitude of the system changes marginally (up to a certain value of time-delay) in the pre-locking and locking region. However, the effect of time-delay in post-locking zone is detrimental. Beyond a certain value of the time-delay, the amplitude becomes large and even the system may become unstable.
10 citations
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TL;DR: In this article, a hyperbolic tangent function was used as a new nonlinear feedback function to re-examine the non-linear feedback in order to solve the problem of more energy-saving and safer course keeping control for large oil tanker under heavy sea state conditions.
10 citations