Required Design Specifications Research Articles

Fabrication of C-Band High-Temperature Superconducting Microstrip Triplexer with High Accuracy

This article presents a miniaturized C-band triplexer fabricated with high-temperature superconducting (HTS) microstrip lines and to be applied to quantum computers. The triplexer consists of three bandpass filters and branch lines. In the design of the bandpass filters, folded step impedance resonators (SIRs) are firstly used to achieve good stopband performances by harmonic suppression. Secondly, cross-coupling structures are also utilized to further improve the passband edge steepness of the bandpass filters. Finally, the parasitic transmission zeros originating from the assembling box sizes are employed to achieve a deeper out-of-band rejection. Three bandpass filters are designed and connected to the common input port of the triplexer. After that, the triplexer is coarsely optimized by advanced design system (ADS) for time-saving and is finely optimized by Sonnet for better accuracy. The optimized layout of the triplexer is fabricated on a 2-inch diameter and 0.5 mm thickness MgO wafer; here, the MgO wafer is double-sided coated with HTS YBa2Cu3O7 (YBCO) thin films. The measured passband bandwidths (return loss greater than 12 dB) of the triplexer are 6.420-6.680 GHz, 6.780-7.030 GHz, and 7.110-7.380 GHz, respectively, which satisfy the required design specifications.

Electromagnetic Investigation on a Sextupole HTS Magnet for RAON

The rare isotope accelerator complex for online experiments (RAON) is a heavy-ion accelerator equipped with an in-flight fragment separator (IF) system and isotope separation online technique in South Korea. Six quadrupole and a sextupole high-temperature superconducting (HTS) magnets are installed in the hot cell of the IF system, which is a high radiation region, to arrange the ion beams and correct the chromatic aberrations of the ion beams. The magnets are developed and installed for RAON at the Institute for Basic Science (IBS), South Korea. Superconducting magnet systems should be capable of a stable operation against high radiation heating and thermally and electromagnetically robust in the intense radioactive hot cell region. In this paper, we describe the design, fabrication, and evaluation of a sextupole HTS magnet. Electromagnetic designs are conducted considering the position of the HTS magnets and the angle of the yoke pole tip <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> The required design specifications are proposed as a part of RAON of IBS considering the following electromagnetic performance: 1) a magnetic field gradient of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ \geq $</tex-math></inline-formula> 3.9 T/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , 2) magnetic field uniformity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ &lt; $</tex-math></inline-formula> 0.5%, 3) effective length of 450 ± 1 mm, and 4) operating temperature of ∼ 45 K.

Behaviour of soft soils following soil mixing in controlled and uncontrolled environments

Soil mixing is considered to be effective for a range of applications and the required design specifications can be achieved by varying the percentage of additives, commonly cement and lime. This paper describes the results of a comprehensive laboratory investigation involving the assessment of cement/lime treatments for improving the geotechnical characteristics of three different soft clays: kaolin, sleech and Belfast clay. The investigation is coupled with an assessment of the durability of the treated soil and the effects of water ingress after treatment. Observations showed that the large-strain Young's modulus increased significantly with curing period after 28 days. The evolution of the small-strain shear stiffness was progressive, and all soils exhibited a steady increase in stiffness, the rate of which reduced as the curing period approached 7 days. The relative increase in strength of the different soils was highly variable. It is postulated that suction was one of the contributors to undrained shear strength gain. When allowed access to water, strength and stiffness increased, although at a much reduced rate. The stress–strain behaviour of kaolin also changed from ductile when untreated to highly brittle as the curing period approached 90 days.

Generating various airfoils with required lift coefficients by combining NACA and Joukowski airfoils using conditional variational autoencoders

The aim of inverse design problem in mechanical design is to obtain shapes that satisfy the required design specifications. It is also desired to obtain varieties of shapes, but finding multiple shapes in a short computation time is difficult using the conventional methods. This paper proposes the use of the conditional variational autoencoders (CVAE) with normal distribution, denoted by N-CVAE, along with the von Mises–Fischer distribution, denoted by S-CVAE, to find multiple solutions for the inverse design problems. Both the CVAE models embed shapes into a latent space. The S-CVAE enables the separation of data in the latent space, whereas the N-CVAE embeds the data in a narrow space. These different features are used for various tasks in this study. In the first task, the dataset consists of only one type of data. Here, S-CVAE outperforms N-CVAE because it can easily separate the data. In the second task, the dataset consists of two different types of airfoils. It is desired to combine two types and to generate new types of data. N-CVAE is useful in this task since it embeds different shapes in the same latent area, due to which, the model outputs intermediate shapes of different types. The shape-generation capability of S-CVAE and N-CVAE are experimentally compared in this study.

Analysis of the Soft-Switching Tuning Effect on the Figures of Merit Involved in the Design of a Class-E Amplifier with Finite DC-Feed Inductance

This paper explores the design of a Class-E amplifier with finite DC-feed inductance using three tuning methods. Furthermore, this work quantifies the impacts of the tuning process (referred to in this paper as the tuning effect) on the main figures of merit (FoMs) of this amplifier. The tuning goals were to guarantee two conditions: zero voltage and zero voltage derivative switching (i.e., soft-switching tuning). To the best of the authors’ knowledge, systematic tuning methods have not been analyzed before for this amplifier topology. Two of them are based on the iterative component tuning process, and they have been explored previously in the design of the conventional class-E amplifier with an RF choke inductance. The last tuning method explores the simultaneous adjustment of the control signal period and one amplifier capacitor. The analyzed tuning methods were validated by extensive simulations of case studies, which were designed following the power specifications of the Qi standard. In 100% and 96% of the case studies, zero voltage switching (ZVS) and zero-derivative voltage switching (ZDS) were achieved, respectively. Furthermore, we identified an unexpected behavior in the tuning process (referred to in this paper as the turning point), which consisted of a change of the expected trend of the soft-switching (i.e., ZVS and ZDS) point, and it occurred in 21% of the case studies. When this behavior occurred and converged to at least ZVS, the tuning process required more iterations and a large number of tuning variables. Additionally, after the tuning process, the total harmonic distortion and output power capacity were improved (i.e., in 78% and 61% of the case studies, respectively), whereas the output power, drain and added power efficiencies deteriorated (i.e., in 83%, 61% and 65% of the case studies, respectively) in the overall case studies. However, we could not identify an improvement in the overall FoMs related to the soft-switching tuning. Furthermore, the tuning impact was significant and produced some improvements and some deleterious effects for the FoMs in each case study, without a clear trend by FoMs or by tuning method. Therefore, the amplifier designer may choose the more favorable tuning method and the related FoM trade-offs for the required design specifications.

Design of an adaptive state feedback controller for a magnetic levitation system

This paper presents designing an adaptive state feedback controller (ASFC) for a magnetic levitation system (MLS), which is an unstable system and has high nonlinearity and represents a challenging control problem. First, a nonadaptive state feedback controller (SFC) is designed by linearization about a selected equilibrium point and designing a SFC by pole-placement method to achieve maximum overshoot of 1.5% and settling time of 1s (5% criterion). When the operating point changes, the designed controller can no longer achieve the design specifications, since it is designed based on a linearization about a different operating point. This gives rise to utilizing the adaptive control scheme to parameterize the state feedback controller in terms of the operating point. The results of the simulation show that the operating point has significant effect on the performance of nonadaptive SFC, and this performance may degrade as the operating point deviates from the equilibrium point, while the ASFC achieves the required design specification for any operating point and outperforms the state feedback controller from this point of view.

Design optimization for mixed-flow pump impeller by improved suction performance and efficiency with variables of specific speeds

In this study, the shape of a mixed-flow pump impeller and its flow characteristics as a function of the specific speed are studied to improve its suction performance and efficiency. The shapes of mixed-flow pump impellers show a trend based on the specific speed. To construct the optimum database, a mixed-flow pump impeller with a specified specific speed is optimally designed using computational fluid dynamics (CFD) and design of experiment (DOE). The design variables of the impeller are defined in the meridional plane and vane plane development for impeller. By analyzing the trends of different mixed-flow pump impeller shapes, the optimized shape that satisfies the design specification can be designed easily. The trend exhibited by the design variables depending on the specific speed is analyzed using the shape of the optimally designed mixed-flow pump impeller. The shape of the mixed-flow pump impeller, as per the required design specification, is designed using the trends of the design variables based on the specific speed. The performance of the designed model is verified using CFD and experimental test.

Design of a Complex fractional Order PID controller for a First Order Plus Time Delay system

Complex fractional Order PID (COPID) controller is an extension to the Real fractional Order PID (ROPID) controller by extending the orders of differentiation and integration to include complex numbers, i.e., two extra parameters (the imaginary parts of the orders of the differentiator and the integrator) are introduced into the formula of the controller. The purpose is to overcome the limitation stemmed from restricting the parameters of the ROPID controller to belong to certain intervals, where this limitation results in a control system that does not satisfy the required design specification accurately. In this paper, analysis and design of COPID controller is presented, and for comparison purposes, both ROPID and COPID controllers are designed for a low pressure flowing water circuit, which is a First Order Plus Time Delay (FOPTD) system. The design specifications are given in frequency domain, which are gain crossover frequency, phase margin, and robustness against gain variation. The design specifications are taken as two cases, simple an rigorous, where the latter is considered to demonstrate the superiority of the COPID controller over the ROPID controller to achieve hard specifications. Although the design of the COPID controller is more complex than that of the ROPID controller, the first achieves the required design specification more accurately.

Noise and Bandwidth Consideration in Designing Op-Amp Based Transimpedance Amplifier for VLC

In a visible light communication (VLC) system, there are many modules involved. One of the important modules is Transimpedance Amplifier (TIA) that resides in the analog front-end receiver (Rx-AFE). TIA is responsible for performing signal conversion from current signal, which is provided from the photodiode (PD) to voltage signal. It is the reason why the TIA should be operating in low noise condition and wide bandwidth of frequency. These will enable a flexible coverage of the VLC system in performing its signal processing. Hence, in this research, we provide considerations of the noise and frequency bandwidth analysis in designing TIA to cope with the required design specification of a VLC system.

A Simulation Modeling Approach Method Focused on the Refrigerated Warehouses Using Design of Experiment

For performance optimization of Refrigerated Warehouses, design parameters are selected based on the physical parameters such as number of equipment and aisles, speeds of forklift for ease of modification. This paper provides a comprehensive framework approach for the system design of Refrigerated Warehouses. We propose a modeling approach which aims at the simulation optimization so as to meet required design specifications using the Design of Experiment (DOE) and analyze a simulation model using integrated aspect-oriented modeling approach (i-AOMA). As a result, this suggested method can evaluate the performance of a variety of Refrigerated Warehouses operations.

A New Method to Tune a Fractional-Order PID Controller for a Twin Rotor Aerodynamic System

This paper proposes a new method to tune a fractional-order Proportional–Integral–Derivative controller (also called \(\mathrm {P}\mathrm {I}^{\uplambda }\mathrm {D}^{\upmu }\) ) for a Twin Rotor Aerodynamic System, which is a nonlinear highly coupled Multi-Input–Multi-Output system. The five parameters of the controller are tuned using optimization to minimize a performance index which is a weighted sum of absolute values of four frequency domain specifications: gain crossover frequency, phase margin, ISO damping property (to be robust against process gain variation), and magnitude peak value at the resonant frequency, where the latter is the new control design specification that is suggested by this paper. The performance of the proposed controller is compared with that of an integer-order Proportional–Integral–Derivative (PID) controller. Simulation results shows that the fractional-order controller outperforms its integer-order counterpart in minimizing the performance index, which results in satisfying the required design specification more accurately. This is demonstrated by first testing the performance of the of the closed-loop system where the fractional-order controller gives better performance than the integer-order controller and second by testing the robustness of the system by changing one of the process parameters, where the fractional-order controller is much more robust, unlike the integer-order controller where the closed-loop system becomes unstable.

Additive manufacturing integration with topology optimization methodology for innovative product design

Additive manufacturing (AM) processes enable the production of functional parts with complex geometries, multi-materials, as well as individualized mass production. Another significant benefit of AM is the ability to produce optimized geometries with near perfect strength to weight ratios. Weight plays a crucial role in many functional parts such as parts used in automotive and aeronautic industries. Current topology optimization techniques, a powerful tool for weight reduction and product optimization in general, do not work well for such kind of process since AM methods necessitate applying own dedicated design rules. This paper reports a product/process optimization study of a simple test case geometry (C-Clip), where structural optimization has been applied using an innovative approach based on the design of lattice structure feasible thanks to additive process adoption. Moreover, it has been conducted a study to evaluate the possible advantages offered by the integration of the two previous approaches in order to verify the required design specifications. The aim of the work has been to evaluate the potentiality offered by the integration of the two structural optimization approaches (topological and lattice structures design) to obtain innovative and highly performing structures. This activity represents a necessary step for the definition and the subsequent development of a methodology aimed to the creation of structures obtained with this combined design approach. In order to define an objective evaluation of the component performances, appropriate Key Performance Indicators (KPI) have been developed. An engineering intelligence tool has been used to post process the generated optimization results for the three different approaches. Finally, the first three “best” structural solutions have been manufactured by 3D printing machine, with scaled dimensions, in order to evaluate the printing time considering the geometry complexity for the chosen structural layout in order to have useful feedbacks on Product/Process choices interaction.

Acoustic Optimization of a High-speed Train Composite Sandwich Panel Based on Analytical and Experimental Transmission Loss Evaluation Integrated by FE/Test Correlation Analysis

Present work purpose is to optimize the acoustic attenuation properties of a composite sandwich panel used for a high-speed train structure, choosing the best panel configuration which allows to improve the performances. Firstly, Nilsson's analytical formulation for Transmission Loss (TL) evaluation has been implemented and experimentally validated on a typical material used for high-speed railway applications, highlighting the opportunity to use a different material to satisfy the new required design specifications. Different materials and stratifications have been then considered and TL parameter of each configuration have been calculated using Nilsson's formulation, characterizing acoustic behavior in the frequency domain. Once found the composition which ensures the best compromise between high acoustic insulation and low weight, the panel has been physically realized. Finally, an experimental and a numerical modal analysis have been performed on it. Starting from both FE simulation and impact testing outcomes, a correlation study through the computation of the Modal Assurance Criterion (MAC), has been carried out. A good agreement between numerical and experimental analyses has been found, obtaining a reliable FE model for future improvements.

VRFB를 위한 BOP 구성 및 BMS 기능구현에 관한 연구

This paper proposes a study on the configuration of balancing of plant(BOP) and implementation of battery management system(BMS) functions for vanadium redox flow battery(VRFB) and propose a method consists of sensor and required design specifications BOP system configuration. And it proposes an method of the functions implementation and control algorithm of the BMS for flow battery. Functions of BMS include temperature control, the charge and discharge control, flow control, level control, state of charge(SOC) estimation and a battery protection through the sensor signal of BOP. Functions of BMS is implemented by the sensor signal, so it is recognized as a very important factor measurement accuracy of the data. Therefore, measuring a mechanical signal(flow rate, temperature, level) through the BOP test model, and the measuring an electrical signal(cell voltage, stack voltage and stack current) through the VRFB charge-discharge system and analyzes the precision of data in this paper. Also it shows a good charge-discharge test results by the SOC estimation algorithm of VRFB. Proposed BOP configuration and BMS functions implementation can be used as a reference indicator for VRFB system design.

Research on the Airborne Pulse Doppler Radar Jamming System Tester

This paper introduces the design of an airborne pulse Doppler radar jamming system tester. Based on a detailed analysis of the functional structure of the radar-jamming system, we summarize the important failure mode. To achieve fault location and performance testing, we have developed an automatic detector for the radar-jamming system, the device uses a mode of hardware platform and software platform, and it can reach the purpose of fault location by a method of encouraging input and measuring the output of each of the radar-jamming system failure mode individually. The automatic test instrument has the features of simple operation, high degree of automation, real-time, scalable, and actual use of running proves it to reach the required design specifications, the test with good results.

ADPLL design parameters determinations through noise modeling

This paper presents a methodology to determine all-digital phase-locked loop (ADPLL) circuit variables based on required design specifications, including output phase noise, fractional spur and locking time. An analytical model is developed to characterize the effects of different noise sources on ADPLL output phase noise and fractional spur. Applying the proposed noise model, circuit variables in ADPLL can be properly selected to meet phase noise, fractional spur and locking time requirements. For model validation, we collect ADPLL circuit designs published in recent literatures and perform model analysis. The analysis results and hardware measurements obtain good agreements.

Efficient design of nanoplasmonic waveguide devices using the space mapping algorithm

We show that the space mapping algorithm, originally developed for microwave circuit optimization, can enable the efficient design of nanoplasmonic waveguide devices which satisfy a set of desired specifications. Space mapping utilizes a physics-based coarse model to approximate a fine model accurately describing a device. Here the fine model is a full-wave finite-difference frequency-domain (FDFD) simulation of the device, while the coarse model is based on transmission line theory. We demonstrate that simply optimizing the transmission line model of the device is not enough to obtain a device which satisfies all the required design specifications. On the other hand, when the iterative space mapping algorithm is used, it converges fast to a design which meets all the specifications. In addition, full-wave FDFD simulations of only a few candidate structures are required before the iterative process is terminated. Use of the space mapping algorithm therefore results in large reductions in the required computation time when compared to any direct optimization method of the fine FDFD model.

Robotic Forceps Manipulator With a Novel Bending Mechanism

This paper proposes a new bending technique with a screwdrive mechanism that allows for omnidirectional bending motion by rotating two linkages, each consisting of a right-handed screw, a universal joint, and a left-handed screw. The new screwdrive mechanism, termed double-screw-drive (DSD) mechanism, is utilized in a robotic forceps manipulator for laparoscopic surgery. A robotic forceps manipulator incorporating the DSD mechanism (DSD forceps) can bend without using wires. Without wires, it has high rigidity, and can bend at 90° in any arbitrary direction. In addition, the gripper of the DSD forceps can perform rotational motion, which is achieved by rotating a third linkage in the DSD mechanism. Opening and closing motions of the gripper are attained by wire actuation. Fundamental experiments examining the bending force and the accuracy of the DSD forceps were conducted, and an analysis of the accuracy was performed. Control of the DSD forceps through a teleoperation system was achieved via a joystick-type manipulator. A servo system was constructed for each linkage and the wire actuation mechanism, and tracking control experiments as well as a suturing experiment were conducted. The results of the experiments showed that the required design specifications were fulfilled. Thus, the validity of the DSD forceps was demonstrated.

A review and analysis of current computer-aided fixture design approaches

A key characteristic of the modern market place is the consumer demand for variety. To respond effectively to this demand, manufacturers need to ensure that their manufacturing practices are sufficiently flexible to allow them to achieve rapid product development. Fixturing, which involves using fixtures to secure workpieces during machining so that they can be transformed into parts that meet required design specifications, is a significant contributing factor towards achieving manufacturing flexibility. To enable flexible fixturing, considerable levels of research effort have been devoted to supporting the process of fixture design through the development of computer-aided fixture design (CAFD) tools and approaches. This paper contains a review of these research efforts. Over seventy-five CAFD tools and approaches are reviewed in terms of the fixture design phases they support and the underlying technology upon which they are based. The primary conclusion of the review is that while significant advances have been made in supporting fixture design, there are primarily two research issues that require further effort. The first of these is that current CAFD research is segmented in nature and there remains a need to provide more cohesive fixture design support. Secondly, a greater focus is required on supporting the detailed design of a fixture's physical structure.

Efficient approach to designing a Schmidt-Cassegrain objective for a remote sensing satellite

This paper presents an efficient approach to designing a Schmidt-Cassegrain objective for a remote sensing satellite. The objective is required to have multispectral operational bands, with three spectral channels distributed along the range (0.5 to 0.9 mum), as well as a panchromatic channel; 4 degrees field of view; distortion smaller than 0.3%; and a modulation transfer function, at 50 lines/mm spatial frequency, better than 0.5 and 0.35 at the center and edge of the field of view. The proposed design approach is based on Slyusarev's theory of aberrations and optical design. An image quality index is formulated as a function of optical system component powers and axial distances. For each combination of parameters, there exists a possible solution that can be realized into a thin lens system by solving Seidel sum equations. The final design is then reached by a simple and quick optimization step. The best three designs are compared in terms of initial values of optical system parameters and final design specifications. The best system image quality is thoroughly analyzed. All three presented designs meet and exceed the required design specifications.