Sensitivity Analysis for Transient Response of the Transmission Line Network

The authors have developed a general-purpose simulation system for the design of link mechanisms. Topological and Kinematic analyses have already been referred to in the preceding paper. In this paper, methods for the dynamic analysis of link mechanisms with controllers, such as transient response and vibration analysis, are proposed. Both the characteristics of the control system and the equations of motion of the mechanical system are automatically and simultaneously transformed into nonlinear state equations. In transient response analysis, for example, the responses of joint displacements, etc., are calculated by the numerical integration of these equations. In vibration analysis, the state equations are linearized around the desired trajectory to calculate the eigenfrequency, mode shape, and transfer functions. The proposed methods were applied to an industrial fobot, and the effectiveness of the methods was ascertained.

An intuitive approach to the convolution problem allows the transient response sensitivity of zero velocity lag servomechanisms to be readily sketched. This procedure leads to a considerable insight into the advantages of feedback compensation in sensitivity reduction; this is much greater than any advantage obtained in choosing between alternative unity feedback designs, and is confirmed by Monte Carlo simulation. Prediction of transient response sensitivity to parameters other than system gain is readily achieved and illustrated by the prediction of the relative importance of elemental blocks of a sixth-order aircraft blind landing system. Maximum percentage overshoot is seen as a critical part of the deterministic performance specification. Not only does the maximum value of the basic sensitivity function increase with maximum percentage overshoot, but the sensitivity function is more oscillatory, with the first turning point no longer giving the peak value.

During fast gas-turbine engine acceleration and deceleration, the transient vibration effects in bladed disk vibration become significant and the transient response needs to be calculated. In this paper, an effective method is developed for efficient calculations of the transient vibration response for mistuned bladed disks under varying rotation speeds. The method uses the large-scale finite element modeling of the bladed disks allowing the accurate description of the dynamic properties of the mistuned bladed disks. The effects of the varying rotation speed on the natural frequencies and mode shapes of a mistuned bladed disk and its effects on the amplitude and the spectral composition of the loading are considered. The dependency of the modal characteristics on the rotation speed is based on the evaluation of these characteristics at reference points followed by the interpolation to obtain values at any rotation speed from the operating range. A new method has been developed for the interpolation of mode shapes while preserving the orthogonality and mass normalization of the mode shapes. The method of mode shape interpolation is elaborated for tuned and mistuned bladed disks. The accuracy and efficiency of the method are demonstrated on test examples and on analysis of transient forced response of realistic bladed disks.

Transient response testing has been shown to be an economical technique for testing linear macros in mixed-signal systems. Previously reported work on the analysis of transient responses has shown how the response from a linear network can be processed to generate a single figure, termed the index of functionality, which is an absolute measurement of device functionality and on which pass/fail decisions are subsequently made. However, if the circuit response is deeply buried in the mixed-signal system, it must first be extracted before it can be processed. The paper details the results of an investigation into the effects of sampling, quantising and extracting transient responses serially through a digital scan path before processing. By understanding the mechanisms by which errors introduced by the sampling and quantisation process manifest themselves in the index of functionality, it is possible to optimise the quantisation parameters for a particular test situation and test to any required standard.

Dynamic response of water-rich tunnel subjected to plane P wave considering excavation induced damage zone

The traditional frequency domain transfer path analysis has become a popular method to detect and diagnose vehicle NVH problems. Unfortunately, due to its reliance on frequency transfer functions, the approach is strictly effective only for linear time-invariant system and steady-state response. This limitation prevents the method from being applied to transient and/or nonlinear behavior such as clunk, shudder, and tip-in and tip-out. In this paper, a novel time domain transfer path analysis is proposed to deal with a class of non-linear transient response problems. It combines the versatility of the transfer path analysis for tracking transmission of vibratory energy between substructures and generality of the time domain analysis for treating transient response that is also nonlinear in nature. The formulation that is derived by combining the spectral-based substructure method and a discrete, piecewise convolution theory is applied to a lumped parameter system, and the results are compared with output from a direct numerical integration of the nonlinear equations of motion. Comparison results show significant promise and appear to be usable for solving real-life vehicle problems that are highly transient with moderate level of nonlinearity present.

Recent literature on building energy performance simulation leans toward implementing uncertainty analysis (UA), instead of deterministic solutions, to handle ever-existing and pivotal uncertainties in building design decision-making process. Variations in weather temperature, degradation of building envelope material properties over time, and random behavior of occupants, among all, are the key sources of uncertainty in building energy consumption predictions. The UA couples to the sensitivity analysis (SA) to identify the most influential inputs on the uncertainties of the building energy consumption. This paper describes a newly-developed UA and SA predictive tool for building energy performance simulations. Energy performance simulations are based on a resistance-capacitance thermal model for the building. For a hypothetical residential building in College Station, Texas, USA, the present work describes and compares predicted probability distribution and sensitivity indexes produced by the UA-SA tool using a transient (dynamic) response analysis (TRA) and static response analysis (SRA). For brevity, the analysis considers uncertainty only for the exterior walls’ parameters including thickness, thermal conductivity, heat transfer coefficient, density, and heat capacity; i.e., a five-dimensional problem is solved. Compared to the TRA, predictions from the SRA underestimate the annual energy consumption up to 30%; however, SRA is significantly faster. Nonetheless, sensitivity indexes from the SRA and TRA closely match.

Analysis of transient response of a unit proton-exchange membrane fuel cell with a degraded gas diffusion layer

Design sensitivity analysis for transient response of non-viscously damped systems based on direct differentiate method

In this paper, an experimental and numerical investigation were conducted to develop an understanding of the importance and role played by honeycomb design parameters in transient response of aircraft sandwich with honeycomb core under the transient load. Forced vibration under transient load test was implemented on sandwich panel with honeycomb core specimens. Vibration rig with specific equipment was manufactured. Finite element simulation for the sandwich panel with honeycomb core were developed and analyzed by Ansys software package. Modal analysis and transient response analysis have been carry out to obtain the numerical transient response. The obtained results show a good agreement between above approaches with conformity by 85% percentage. The core high, cell size and cell wall thickness were selected to explore the effect of honeycomb parameters on the transient response of sandwich structure. In order to obtain the optimum condition, Response Surface Methodology (RSM) was used. Results showed that minimum transient response were found at 20 mm core height, 25 mm size cell and 1.5 mm cell wall thickness. Where, the optimal value minimum transient response equal to 0.0019 mm.

In this paper, an efficient control algorithm for an Intelligent Controller Induction Motor Drive system using Fuzzy Logic Approach has been proposed. The Indirect Vector Control principle has been employed to control the Induction Motor. Next, a two-degree-of freedom controller is proposed to improve the system performance. The controller design algorithm can be applied in an adjustable speed control system to obtain good transient responses and good load disturbance rejection abilities. The proposed controller has been analyzed using computer simulation and compared with a simple conventional Controller strategy. The simulated controller performances have been finally verified experimentally using TMS320C6711 Digital Signal Processor. The results obtained substantiate the robustness and effectiveness of Intelligent Controller for high performance of Induction Motor.

We present DAGSENS, a new theory for parametric transient sensitivity analysis of Differential Algebraic Equation systems (DAEs), such as SPICE-level circuits. The key ideas behind DAGSENS are, (1) to represent the entire sequence of computations, starting from DAE parameters, all the way up to the objective function whose sensitivity is needed, as a Directed Acyclic Graph (DAG) called the "sensitivity DAG", and (2) to compute the required sensitivities efficiently (with time complexity linear in the size of the sensitivity DAG) by leveraging dynamic programming techniques to traverse the DAG. DAGSENS is simple, elegant, and easy-to-understand compared to existing sensitivity analysis approaches; for example, in DAGSENS, one can switch between direct and adjoint transient sensitivities just by changing the direction of DAG traversal (i.e., topological order vs. reverse topological order). Also, DAGSENS is significantly more powerful than existing sensitivity analysis approaches because it allows one to compute the sensitivities of a much more general class of objective functions, including those defined based on "events" that occur during a transient simulation (e.g., a node voltage crossing a particular threshold, a phase-locked loop (PLL) achieving lock, a signal reaching its maximum/minimum value during a transient run, etc.). In this paper, we apply DAGSENS to compute the sensitivities of important event-driven performance metrics in several real-world electronic and biological applications, including high-speed communication (featuring sub-systems such as I/0 links and PLLs), statistical cell library characterization, and gene expression in Drosophila embryos.

A new design approach is presented in this study for tuning of proportional-integral-derivative (PID) controller parameters in a DC–DC buck converter utilizing a hybrid whale optimization algorithm (WOA) with simulated annealing (SA), namely the WOASAT algorithm, which uses a tournament selection mechanism. The proposed algorithm’s efficacy ensures that the optimum PID controller parameters are tuned quickly and that the quality of tuning is high. A time domain performance index is utilized to validate the proposed WOASAT-based PID controller’s performance. In addition, from the comparative results of statistical analysis, frequency response analysis, transient response analysis, disturbance rejection analysis, and performance indices analysis, the proposed WOASAT-PID controller was found to be more efficient than the SA-PID controller and WOA-PID controller in enhancing the buck converter’s transient response. Cite this article as: Hekimoğlu B, Ekinci S. Optimally Designed PID Controller for a DC-DC Buck Converter via a Hybrid Whale Optimization Algorithm with Simulated Annealing. Electrica, 2020; 20(1): 19-27.

The complex fracture network created by multistage hydraulic fracturing has been recently described by a triple porosity model. Existing triple porosity models typically assume sequential flow from matrix to micro fractures and from micro fractures to hydraulic fracture. Modeling simultaneous depletion of a matrix block into both micro and hydraulic fractures entails solution of a two dimensional continuity equation that is challenging by analytical or even semi-analytical methods. In addition, analysis with analytical models and type-curves provides deterministic and homogeneous estimates, rendering uncertainty analysis of fracture properties difficult. In this paper, we use a commercial reservoir simulator to solve the transient response in a segment of a hydraulically fractured horizontal well. This is a triple porosity medium in which matrix blocks deplete into the two fracture networks simultaneously. The proposed model is used to analyze the actual rate data from a tight oil well. It is assumed that the obtained results would characterize the mean estimate of the corresponding fracture parameters. Additional heterogeneous models of fracture properties including its total number and intensity (spacing) are assigned stochastically and subjected to flow simulations to demonstrate their impact on production performance. The resulting production profiles converge to those of dual and triple porosity models at the limiting cases. Uncertainties due to pressure interference between natural fractures and inter-well fracture communication are also investigated. The variability (spread) of the simulation results would capture the sensitivity due to uncertainty in fracture distributions. Our results also show that history-matched fracture half-length strongly depends on the number of micro-fractures implemented in the static simulation model. The estimated value of fracture half-length significantly decreases by increasing the number of micro-fractures from zero, representing the dual porosity system. This paper systematically investigates applying stochastic models of fracture heterogeneity for production data analysis. It illustrates efficient integration of numerical simulations with analytical solutions to quantify the uncertainty in production performance predictions. Information derived from this sensitivity or uncertainty analysis can be used to evaluate existing fracturing operation and to optimize future multi-stage hydraulic fracturing operations.

With increased wire density of integrated circuits and with increased speed of signal, crosstalks due to couplings of wires and wave distortions due to impedance mismatches have become a problem. For the transient analysis of these signals, using the wave digital filter representation of the wires, simulation methods consider them as coupled transmission lines. However, the existing methods construct a digital model depending on the load of the circuits to be analyzed. This paper represents the loss‐less coupled lines of the circuit to be analyzed by equivalent circuits using ideal transformer interconnections and uncoupled transmission lines. Then its power supply and load, its ideal transformer interconnections and its uncoupled transmission lines are modeled individually by digital filter models thus representing the entire circuit with a wave digital filter. Also, digital models are presented for the cases when coupled transmission lines contain lumped parameter elements and branchings. Furthermore, it is shown that lossy symmetrical coupled lines can be represented by equivalent circuits using ideal transformer interconnections and lossy uncoupled lines, and their wave digital filter representations are given. Finally, a wave digital filter representation of a network containing lossy symmetrical coupled lines is given. It is used as a model for wirings on a GaAs substrate, and examples of its transient response analyses are given.