Transfer function

About: Transfer function is a research topic. Over the lifetime, 14362 publications have been published within this topic receiving 214983 citations. The topic is also known as: system function & network function.

Control of nonlinear distributed process systems : Recent developments and challenges

Abstract: hile most deal with vv processes undergraduate process control courses still dynamics and control of lumped chemical using linear transfer function models, key technological needs in growth areas such as semiconductor manufacturing, nanotechnology, biotechnology, and unmanned aerial vehicles have motivated extensive research on analysis and control of complex nonlinear distributed systems across all engineering disciplines. From a control point of view, the distinguishing feature of complex distributed systems is that they give rise to nonlinear control problems that involve the regulation of highly distributed control variables by using spatially-distributed control actuators and measurement sensors. Thus, complex distributed systems cannot be effectively controlled with control methods which assume that the state, manipulated and tobe-controlled variables exhibit lumped behavior or with linear control algorithms derived on the basis of IinearAinearized distributed models. icant nonuniformity of the wafer temperature profile. This, in turn, may lead to film deposition uniformity that does not meet the tight requirements set by the industry (SIA, 1997). This technological need and the complex character (nonlinearities, spatial variations, batch nature) of the RTCVD process motivate the need to control the wafer temperature profile using a nonlinear feedback controller based on a distributed process model. A typical example of this class of problems is the control of titania aerosol reactors to achieve a nearly monodisperse particle-size distribution (Kalani and Christofides, 2000); this is required for titania pigments to obtain the maximum hiding powder per unit mass. Titania aerosol Control of Particle-Size Distributions.

On Multiplicative Transfer Function Approximation in the Short-Time Fourier Transform Domain

Abstract: The multiplicative transfer function (MTF) approximation is widely used for modeling a linear time invariant system in the short-time Fourier transform (STFT) domain. It relies on the assumption of a long analysis window compared with the length of the system impulse response. In this paper, we investigate the influence of the analysis window length on the performance of a system identifier that utilizes the MTF approximation. We derive analytic expressions for the minimum mean-square error (MMSE) in the STFT domain and show that the system identification performance does not necessarily improve by increasing the length of the analysis window. The optimal window length, that achieves the MMSE, depends on the signal-to-noise ratio and the length of the input signal. The theoretical analysis is supported by simulation results

Modeling and Design of Controlled Current Induction Motor Drive Systems

Abstract: A dynamic model for current-controlled induction motor drives is developed, and a transfer function approach to the transient response investigation is formulated by means of d-q variables in the synchronously rotating reference frame. A sample control strategy is discussed, and transfer functions for various combinations of input and output variables are presented. It is shown that both dynamic and static instabilities exist for open-loop operation, but a well-damped closed-loop response is possible if slip frequency and current magnitude control are imposed. A comparison between the analytical transfer function transient performance predictions, the transient respontse predicted by the hybrid computer simulation, and actual laboratory tests is made using frequency response techniques. Bode plots are used to correlate' the results between laboratory and analytical techniques. Hybrid computer and laboratory results are presented to show typical steady-state characteristics and waveforms.

Nonconvex optimization by fast simulated annealing

Abstract: Recent advances in the solution of nonconvex optimization problems use simulated annealing techniques that are considerably faster than exhaustive global search techniques. This letter presents a simulated annealing technique, which is t/log (t) times faster than conventional simulated annealing, and applies it to a multisensor location and tracking problem.

Tests of stability of multidimensional filters

Abstract: Novel stability criteria are established, for multidimensional digital and analog filters with rational transfer functions. The criteria generalize and simplify the stability test for two-dimensional digital filters developed by Huang [4], and significantly simplify the corresponding tests of stability of arbitrary multidimensional filters established by Anderson and Jury [6].