Initial Design Parameters Research Articles

Performance improvement for the CMOS rail-to-rail amplifier via APSO-based design and SNN’s training

This paper proposes an adaptive Particle Swarm Optimization(APSO) global search algorithm and Spiking Neural Network(SNN) surrogate model-based optimization design method for analog integrated circuits performance enhancement. The initial design parameters are calculated by numerical computation. The global design space is extended and explored using APSO in the main loop, with constraint testing ensuring the transistor works in the right conditions. A Spiking Neural Network (SNN) model aids in predicting circuit performance during local searches, in which training data for the local design space is generated through parallel SPICE simulations. The optimization framework is applied to rail-to-rail amplifiers of two topologies. The results show that the proposed method accelerates the optimization process, achieving up to a 35.4x speed enhancement compared to Particle Swarm Optimization(PSO) based on the SPICE simulation. Moreover, Compared with traditional approaches based on multiobjective optimization, the proposed method provides an advantage in performance improvement and is valid for different CMOS processes.

Prescribed-time tracking with prescribed performance for a class of strict-feedback nonlinear systems

In this paper, we will investigate the prescribed-time tracking with prescribed performance for a class of strict-feedback nonlinear systems. A control strategy will be proposed to achieve the tracking error constrain by prescribed performance bound (PPB) and converge to zero in prescribed-time. The PPB constrains not only the convergence rate, but also the maximum overshoot of the tracking error. The tracking error will converge to zero in prescribed-time. Such a prescribed-time is irrespective of both initial conditions and design parameters. First, by incorporating the PPB into the original system via a transformation, a equivalently transformed system is obtained, which is unconstrained and convenient for control design. Then, with the help of backstepping, a controller is recursively designed to guarantee that the tracking error satisfies the PPB all the time and converges to zero in prescribed-time. The key to designing the controller is that a fractional term is introduced when designing the virtual stabilizing function during each step of backstepping, which in turn decreases the Lyapunov function to origin within prescribed-time. Finally, two examples are presented to demonstrate the validity of our proposed control strategy.

Analysis of Initial Design Parameters Affecting the Capacity of Shortened Tracks of the Marshalling Yard of a Freight Station

The article analyzes one of the current methods of determining the necessary track development of the marshalling yard of a freight station. Special attention is paid to the issue of identifying the initial design parameters that have a significant impact on the required number of shortened marshalling tracks. The complex multivariant task of determining the capacity of track development requires specification of the solution of some issues of this aspect.

Advancements in base isolation for seismic mitigation: Perspectives on elastomeric and lead rubber bearings

Base isolation represents an environmentally sustainable and highly effective technique for mitigating structural responses to strong seismic forces generated by plate boundary tectonic activities. Its primary benefits include preventing structural collapse, minimizing property damage, and safeguarding human lives during severe earthquakes. This passive, energy-efficient approach is often complemented by supplementary dampers to further reduce seismic impact. This study provides a comprehensive overview of elastomeric and lead rubber isolators, covering their theoretical, experimental, and numerical aspects. The paper examines the seismic response of structures equipped with elastomeric and lead rubber bearings, including a discussion of their pros and cons. This paper presents the comparison of fixed base and rubber isolated base in SAP 2000 to assess the effectiveness of base isolation. Additionally, it presents findings from shaking table tests, relevant building codes, and practical applications, considering the impact of events beyond initial design parameters. The review delves into the historical evolution of elastomeric and lead rubber-bearing systems, offering valuable insights into their contemporary understanding. Furthermore, the paper introduces three-dimensional isolators designed to attenuate ground motion responses in both horizontal and vertical directions. It investigates the effects of soil-structure interaction and evaluates isolator responses under blast and impact aircraft loading conditions. Notably, specific types of bearings exhibit exceptional energy dissipation capabilities during catastrophic seismic events, leading to reduced floor acceleration and inter-storey sway at critical levels. In conclusion, the study offers future recommendations and identifies potential constraints in this field

Operating characteristics and design parameter optimization of permanent magnet linear generator applied to free-piston energy converter

A tubular permanent magnet linear generator (PMLG) with axial magnetized is proposed for the free-piston engine generator (FPEG). The structures and test rigs of the PMLG and FPEG prototypes are introduced. The working characteristics of the PMLG in FPEG system are analyzed under ignition conditions. A 2D finite element model of the PMLG is designed and verified based on initial design parameters and test results. The influences of key operating parameters on the output performance of PMLG are studied. On these basis, when considering the actual motion characteristics of the PMLG in FPEG system, the effects of different structural parameters on the power generation performance and efficiency (h) are investigated. Results show that when the working frequency of the FPEG is relatively small, the displacement profile resembles a sinusoidal curve. As the working frequency and stroke length increase, the power generation increases rapidly. As the air gap length and back iron shaft diameter decrease, and the stator slot number increases, the output voltage (U), current (I), power (Pout), and total loss power (Ploss) show an approximately linear increasing trend. As the pole arc coefficient and stator tooth width increase, the U, I, Pout, and Ploss first increase and then decrease. As the stator yoke thickness increases, the U, I, and Pout increase rapidly and then tend to stabilize. Besides, these structural parameters have little impact on power generation efficiency of this PMLG.

Adaptive practical prescribed-time formation tracking of networked nonlinear multiagent systems with quantized inter-agent communication

This paper presents an adaptive practical prescribed-time (PPT) control design for distributed time-varying formation tracking of networked uncertain strict-feedback nonlinear systems with quantized inter-agent communication under a directed network. The primary contribution of this study is to develop a time-varying formation tracking strategy to resolve the quantized inter-agent communication problem in the prescribed-time control field. A practical finite-time function is introduced to design an adaptive PPT formation tracker using quantized output information of neighbors, which can be used continuously after a prescribed time. A neural-network-based design methodology that utilizes the quantization-based distributed errors is presented to deal with the unknown virtual and actual control coefficient functions in the command-filtered backstepping design. Distributed adaptive compensating signals are constructed using the practical finite-time function to compensate for command-filter errors, unknown nonlinearities, and quantization errors in the PPT tracking framework. We prove that despite the presence of quantized inter-agent communication, the time-varying formation tracking errors converge to a compact set including the origin within the pre-assigned convergence time, where the compact set can be adjusted by choosing a design parameter of the practical finite-time function, and the prescribed settling time is independent of the initial system conditions and design parameters. The effectiveness of the proposed theoretical approach is confirmed through two simulation examples.

Optimal Design of Asynchronous Motor based on Finite Element Simulation

Aiming at motors’ deficiencies such as short life, low efficiency, and high cost in China, this paper optimizes the design of asynchronous motors, so as to improve its performance and efficiency, prolong its life, and reduce its cost. Simulating an asynchronous motor by Maxwell, a finite element simulation software, this paper analyzes the distribution diagrams of waveform and magnetic field including its voltage, current, torque, and back electromotive force to verify the design reliability. Moreover, the parametric simulation of the motor is implemented through the function of Maxwell parameter solver, and the electromagnetic performance under different initial design parameters is simulated. Then, a sensitivity analysis algorithm is adopted to analyze the sensitivity of the motors’ initial design parameters. Meanwhile, this paper establishes the platform of motor optimization design, through which the optimization design of motors with different specifications can be fulfilled.

The Structural Design and Optimization of Top-Stiffened Double-Layer Steel Truss Bridges Based on the Response Surface Method and Particle Swarm Optimization

A lightweight design optimization algorithm is proposed to optimize the design parameters of stiffened double-layer steel girder bridges, the aim of which is to improve structural safety and reduce superstructure works. Taking a top-stiffened double-layer steel truss bridge as the reference project, a multiscale mixed-element model of the initial design parameters is established, and its computational accuracy is verified. Considering the structural configuration and loading characteristics of the bridge, the elastic modulus of steel, the deck plate thickness, the stiffening vertical bar height, and the relative distance between the double-layer main girders are selected as the design parameters for optimization. The mid-span vertical deflection, the axial forces in the stiffeners, the bottom plate of the deck, the compressed web tube at the pier top, and the quantity of superstructure works are chosen as the objective functions to be minimized. A lightweight calculation equation reflecting the relationship between the optimization parameters and the objective functions is established using the response surface method (RSM). Subsequently, an improved weighted particle swarm optimization (WPSO) model is employed to perform the multi-objective optimization of the design parameters for the bridge, and the results are compared with those obtained from the multi-objective genetic algorithm NSGA-II. The results show that the RSM accurately fits the numerical relationship between the optimization parameters and the objective response functions. When minimizing the quantity of superstructure works as the primary control objective and minimizing the mid-span vertical deflection and the axial forces in the compressed web tube at the pier top as secondary control objectives, the optimization results achieved by WPSO outperform those obtained by NSGA-II. The optimized results lead to reductions of 11.09%, 3.92%, 7.56%, 4.45%, and 8.38% in the respective objective function values of the structure. This method has important theoretical significance for the optimization of structural design parameters.

Composition optimization of PMMA base denture reinforced with different percentages of Nano Hydroxyapatite and alumina particles to obtain highest KIc and KIIc values using hybrid IWO/PSO algorithm

Composition of three-phase dental denture (Polymethyl methacrylate or PMMA + Nano Hydroxyapatite + Nano Alumina) was optimized using hybrid IWO/PSO algorithm to obtain the highest KIc and KIIc. First, initial fracture toughness tests were performed on nine groups of PMMA base dentures with different percentages of ingredients. Symmetric single edge notch beam and asymmetric three-point bend beam with inclined crack were used for KIc and KIIc testing, respectively. The initial design parameters were considered as: {75–100% PMMA, 0–10% Nano Hydroxyapatite and, 0–15% Nano Alumina}. As the initial guess values for starting the hybrid optimization algorithm, B-spline curves (as the cost function) were fitted to the experimental results of both modes I and II. Then the IWO/PSO algorithm was run to find the optimum composition and maximum fracture toughness value of each mode. The best KIc was found for the composition of {78.5% PMMA + 9% Nano Hydroxyapatide + 12.5% Nano Alumina}. Similarly, using the hybrid IWO/PSO algorithm the optimum composition of {83.4% PMMA + 8.7% Nano Hydroxyapatide + 7.9 % Nano Alumina} was obtained to gain the highest KIIc. The experimental fracture toughness values obtained from the proposed compositions via employing the hybrid algorithm were approximately 40% higher than the all tested nine groups of PMMA base dentures under both modes I and II. The fracture toughness ratio KIIc/KIc of the optimum mix-designs predicted by the hybrid algorithm was equal to 0.78 and showed good agreement with the experimental KIIc/KIc ratio. The fracture toughness for any desired mixed mode condition can also be predicted in-terms of the KIc and stress intensity factors and T-stress of the desired mode mixity.

Seismic isolated bridge performance evaluation and design proposal using artificial neural network

AbstractSeismic isolators such as rubber bearings and other dampers are critical components of seismic design. The hysteresis behavior of such bearings is complicated, and engineers are using a bilinear model or equivalent linearization method in design practice. The response evaluation and initial design parameter assumptions are highly dependent on engineers' expertise and need repeated analysis. Therefore, this study proposed a machine learning‐based approach to conduct bridge seismic isolation performance evaluation and design parameters proposal without repeating the nonlinear simulations. The training data were generated by conducting a nonlinear time history analysis of the bridge structure model with input design earthquakes. Four trained three‐layer neural network models could perform bridge seismic response evaluation, predict the structure's seismic response, and suggest design proposal using some input parameters.

Prescribed-time output stabilization for mismatched uncertain systems using state-feedback control based on extended disturbance observer

This paper presents a prescribed-time output stabilization method for mismatched uncertain systems using state-feedback control and extended disturbance compensation. The settling-time interval is divided into a disturbance-estimation interval plus an output-stabilization interval, where a prescribed-time extended disturbance observer with finite time-varying gains (PTFG-EDO) and a modified time–space deformation approach (TSDA) control are applied in these intervals, respectively. Due to the prescribed-time convergence of the PTFG-EDO and the modified TSDA control, the settling time of the closed-loop system can be predetermined irrespective of the initial conditions, design parameters, and admissible disturbances. The chattering problem of the original TSDA control is greatly alleviated, and the disturbances, especially the mismatched disturbance which cannot be handled in the original TSDA control, are significantly suppressed. The effectiveness of the proposed PTFG-EDO-based control is demonstrated via numerical simulations.

Method for algebraic calculation of initial design parameters of a two-element telecentric f-theta lens.

A method for the algebraic calculation of paraxial design parameters of a telecentric f-theta lens is described. Moreover, a third-order aberration analysis is performed for a telecentric f-theta lens composed of two optical elements. The method can be used to calculate the starting optical design of telecentric f-theta lenses, which can be used, for example, in laser material processing, optical imaging systems, and optical metrology. The initial design parameters then can be used for further optimization in optical design software.

Reduced-Order Observer-Based Preassigned Finite-Time Control of Nonlinear Systems and Its Applications

In this article, a preassigned finite time control problem of nonlinear systems in strict-feedback form is investigated. From the perspective of arbitrary settling time, an appropriate preassigned finite-time performance function (PFPF) is constructed, and the preassigned finite-time stability (PAFS) is established, where the settling (convergence) time is not only completely unconcerned with initial conditions and design parameters but also more flexible. Furthermore, the backstepping technique and reduced-order observer are used to obtain the preassigned finite-time control scheme. The stability criteria of PAFS are developed to guarantee that the output can quickly converge to an arbitrarily small zone in preassigned time, and all signals of the closed-loop control system are PAFS. In the end, simulation examples verify the effectiveness of the presented method.

Prescribed-Time Output Feedback Control for High-Order Nonlinear Systems

In this article, a novel prescribed-time output feedback control strategy is developed for high-order nonlinear systems. To begin with, a new coordinate transformation method is proposed, under which a time-varying gain that goes to infinity towards the terminal time and a constant scaling gain are simultaneously introduced into the system. Then, the reduced-order observer and output feedback controller are successfully constructed by using the homogeneous domination approach. Unlike many existing results, our proposed control strategy can ensure that the convergence time is independent of both the initial conditions and design parameters, and the convergence rate of the system is adjustable. Moreover, the design process is simplified and the control scheme can operate even after the prescribed-time. Finally, a simulation example is used to verify the validity of the proposed control strategy.

Mechatronic linear movement device for constructing surfaces of complex shapes with the possibility of force measurement

In the modern world, there is a trend towards the introduction of mechatronics in an increasing number of areas of science and technology in order to solve complex problems of controlling functional movements. One of these problems is the problem of forming surfaces of complex shapes. This task is relevant in many areas of human activity such as industry, art, and human-machine interfaces. However, among the existing solutions, there are none that could provide the possibility of forming complex surfaces under the influence of a load, while providing compact weight-dimensional characteristics. The purpose of this article is to develop the concept of a mechatronic device for the tasks of constructing surfaces of complex shape with high accuracy, the possibility of positioning under a large axial load, and measuring the axial forces exerted by objects of manipulation. The article selects the initial design parameters based on the analysis of devices similar in functionality. Next, the selection of compo-nents, the development of the layout of functional components, control electronics, and design, and the implemen-tation of a 3D model of the final device are carried out. It also describes a method for managing a group of re-ceived mechatronic devices by using a single data bus with a specialized protocol.

I/O system of V-band second harmonic gyrotron for 100/200 kW operation

This paper presents the design studies of the common input and output system of a continuous wave (CW), V-band gyrotron at second harmonic for plasma diagnostics application. Two different designs are carried out with design 1 operating at TE7,3 mode having same geometrical parameters for dual power operation of 100 kW and 200 kW and design 2 operating at TE8,3 mode has same geometry that can support dual power operation of 100 kW and 200 kW respectively. The selection of the initial design parameters has been done using our in-house computer code Gyrotron Design Studio Second Harmonic Version 2020 (GDS2H-2020). The electron guns along with magnetic guidance systems are designed to generate electron beam with the required beam parameters using software package EGUN. The design and optimization of the Non-Linear Taper (NLT), Quasi-Optical Launcher (QOL) and RF window are carried out for both the designs. NLTs are optimized for maximum transmission efficiency of the desired modes using Computer Simulation tool (CST). QOLs are designed for converting the operating modes into Gaussian-like mode using commercial software packages Launcher Optimization Tool (LOT) and SURF3D. The designs of the single-disk RF window for high-power output beam extraction are performed using CST.

Reliability specification of crack opening in flexural reinforced concrete elements

The paper focuses on the reliability specification of trouble-free operation crack opening in flexural reinforced concrete structures. The opening width is considered based on the reinforcement safety, i.e., safety due to corrosion.The probabilistic approach is used in this paper. Instead of traditional economic indicators, abstract values were used, i.e., measures of safety and corrosion damage of reinforcement. Both values range from 0 to 1. Basic formulas, calculation sequence and results are given herein. The probability of trouble-free operation is calculated under the assumption that all initial design parameters and external influences are distributed according to the normal law. Calculations are performed depending on the crack opening duration and maximum permissible values of crack opening width. The obtained values of the reliability specification of trouble-free operation depend on the maximum permissible values of the standard crack opening width. They not depend on the crack opening duration. Calculation results can be used in the probabilistic approach to reinforced concrete structures.

Method of initial design of a two-element double-sided telecentric optical system.

An algebraic method for finding fundamental parameters of a starting design of a two-element double-sided telecentric lens is introduced in this work. The telecentric lens is formed by two objectives composed of an afocal meniscus lens followed by a cemented doublet. It is used the third-order aberration theory to find the fundamental parameters of the starting configuration of a given optical system. The method gives results which make possible to obtain a good initial design of such a telecentric lens for further optimization using optical design software. The proposed method is presented on an example of finding initial design parameters of the double-sided telecentric lens.

An Innovative Approach to Electrical Motor Geometry Generation Using Machine Learning and Image Processing Techniques

This paper presents a methodology for generating geometries for interior permanent magnet (IPM) motors in electric vehicles (EVs) through the application of artificial intelligence (AI) and image processing (IP) techniques. Due to the implementation of green agreements and policies aimed at reducing greenhouse gas emissions, EVs have become popularity. As a consequence, the improvement studies on the powertrain and battery system of EVs are focused. Especially for the powertrain, design optimization studies of e-motor have increased in the literature. One of the most widely used e-motor topologies is interior permanent magnet (IPM) motor. However, designing the IPM motor presents a challenge due to the dynamic considerations with geometric constraints. Therefore, e-motor designers encounter challenges related to determining initial geometry and the long time of the optimization process. To address these challenges, a novel approach is proposed that leverages machine learning (ML) techniques in combination with IP to generate initial geometries and design parameters for IPM motors. The proposed approach generates images of the motor geometry and extract dimensional features from the resulting images by using artificial neural networks (ANNs). The proposed method performs an analysis of the input vectors to reduce their size using techniques such as Histogram, 2D Maximum, 2D Mean, 2D Minimum, 2D Standard Deviation, and 2D Variance to enhance feature extraction. Additionally, FFT (Fast Fourier Transform) and IFFT (Inverse Fast Fourier Transform) are used to improve the neural network process in generating the image geometry. Further, the generated image geometry is improved by applying digital filtering techniques such as Log, FFT, Log+FFT, Laplacian, Sobel, and Histogram Equalization. Finally, the trained ANNs are tested to validate the results by using Ansys RMXprt and Maxwell. Eventually, the proposed method represents an innovative solution to generating initial geometries for IPM motors in EVs that satisfies desired design requirements. This approach leverages the power of AI and image processing techniques, which could lead to significant improvements in the optimization process for IPM motors, accelerate the designer’s analysis process, and enhance the performance of EVs.

Algebraic method for finding the initial design parameters of a two-element optical system with an afocal meniscus lens.

This work introduces an algebraic method of the calculation of an initial design of a two-element optical system composed of a thick afocal meniscus lens and a thin lens element, which can be formed, for example, by a cemented doublet. The third-order aberration theory is used to find the fundamental parameters of the starting configuration of a given optical system. The method gives results that make it possible to obtain a good starting design for further optimization of such imaging systems using optical design software. The proposed method is presented on two examples of finding the initial design parameters of the objective with an afocal meniscus lens and a cemented doublet.