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Bridging the gap between design and manufacturing specifications for non-rigid parts using the influence coefficient method

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INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 2023年第1-2期127卷 579-597页

作者： Maltauro, Mattia Passarotto, Gianluca Concheri, Gianmaria Meneghello, Roberto Univ Padua Dept Management & Engn Stradella San Nicola 3 I-36100 Vicenza Italy Univ Padua Dept Ind Engn Via Venezia 1 I-35131 Padua Italy Univ Padua Dept Civil Environm & Architectural Engn Lab Design Methods & Tools Ind Engn Via Venezia 1 I-35131 Padua Italy

The manufacturing process may lead non-rigid parts to endure large deformations which could be reduced during assembly. The manufacturing specifications of the single parts should refer to their free state or "as manufactured" state;the functional specifications should instead address the "as assembled" state. Therefore, a functional geometrical inspection requires dedicated fixtures to bring the parts in "as assembled" state. In this paper, through a linearized model that considers fixturing and elastic spring-back, we aim to correlate the functional specification to the manufacturing specifications. The model suggests a hybrid approach called "restricted skin model" that allows to reduce the degrees of freedom considering the form error when relevant. Firstly, the framework is verified in a mono-dimensional test case. Subsequently, it is verified including FEM simulation and actual measurement for two simple assemblies. The results show that the model can correctly interpret the theoretical assembly behaviour for actual applications. The use of the "restricted skin model" approach shows a negligible difference when compared to full FEM simulation with differences of 2.1 center dot 10(-7) mm for traslations and 6.0 center dot 10(-3) deg for rotations. The comparison with actual measurement values showed an error of +/- 0.2 mm at the assembly features. Furthermore, the linearized model allows a possible real-time application during production that enables to adjust manufacturing specification limits in case of process drifting.

关键词： Geometrical Product Specification Tolerancing Deformable assemblies Compliant assemblies linearized model Skin model Restricted skin model

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Predictive Power Control for a linearized Doubly Fed Induction Generator model 21

Predictive Power Control for a Linearized Doubly Fed Inducti...

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21st International Middle East Power Systems Conference (MEPCON)

作者： Mossa, Mahmoud A. Bolognani, Silverio Minia Univ Elect Engn Dept Fac Engn Al Minya 61111 Egypt Univ Padua Dept Ind Engn Via Gradenigo 6-a I-35131 Padua PD Italy

ISBN: (纸本)9781728152899

The paper is concerned with developing a predictive power control (PPC) approach for a linearized doubly fed induction generator (DFIG). The main contribution of the proposed control procedure is illustrated via reducing the inherent nonlinearity of the DFIG model through introducing new state variables (only four) and through adopting the hysteresis predictive control (HPC) instead of using the proportional integrators (PI) which are usually exist in vector control procedures. The simplicity of the proposed PPC is enhanced through eliminating the pulse width modulation via utilizing the finite control set (FCS) as a voltage vector selection procedure. In order to increase the efficiency of the generation unit (DFIG), a loss minimization methodology (LMM) is proposed based on deriving the optimal reactive power reference. For validating the feasibility of the proposed PPC and the LMM, the DFIG dynamic performance under the proposed PPC is compared with that obtained under applying the classic predictive power control. The obtained results confirm the validity of the proposed PPC in achieving full decoupling between the active and reactive power components at steady-state and transient operation as well. Moreover, the LMM confirms its effectiveness in minimizing the DFIG losses (copper and iron) which results in improving the drive efficiency.

关键词： doubly fed induction generator predictive power control renewable energy systems loss minimization linearized model finite control set

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Sensorless Backstepping Control of Multiphase Induction Machines Under Fault Conditions 3

Sensorless Backstepping Control of Multiphase Induction Mach...

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3rd International Conference on Smart Grid and Renewable Energy (SGRE)

作者： Kouzou, Ahmed Lakhdar Morawiec, Marcin Wilczynski, Filip Gdansk Univ Technol Fac Elect & Control Engn Narutowicza 11-12 St PL-80233 Gdansk Poland

ISBN: (纸本)9781665479080

This paper deals with the sensorless backstepping control of the multiphase induction motor under faulty operation mode. Indeed, the proposed control is based on a linearized model where decoupling problems associated with the nonlinear dq model are eliminated. Whereas, this model is obtained from the linearization of the machine vector model in the stationary reference frame alpha-beta which is achieved by using a non-linearized transformation such as the Z-transformation proposed in this paper. Furthermore, this model can be extended to all planes alpha(n)-beta(n), where the used backstepping technique allows ensuring independent torque and rotor flux stabilization in each plane. Finally, some experimental results are presented for the validation of the proposed control on a specific sensorless benchmark of a five-phase squirrel cage induction motor under fault conditions such as open phase fault on one and two phases.

关键词： Backstepping technique multiphase machine linearized model sensorless control

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A novel interpretation for grid-following virtual inertia of DFIG: Fast power response

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WIND ENGINEERING 2025年

作者： Yang, Jingying Jiang, Chao Guo, Shujia Zhou, Shuyu Cao, Zhizhong Hao, Shuyu Northeast Elect Power Univ Sch Elect Engn 169 Changchun Rd Jilin 132012 Peoples R China State Grid Jilin Elect Power Co Ltd Changchun Peoples R China Zhejiang Univ Sci & Technol Sch Automat & Elect Engn Hangzhou Peoples R China

In order to correct the misunderstanding of previous studies, this article presents a novel interpretation of inertia response of double fed induction generator (DFIG) from system perspective. The dominant factors affecting frequency dynamics are clarified combined with the regulation process. And the differences of inertia responses between synchronous generator (SG) and DFIG are analyzed and illustrated for the first time. To obtain better insight into physical properties of DFIG, a frequency response linearized model of DFIG with inertia emulation is derived according to vector control strategy, and based on the analytical model, the essential reason of frequency support by DFIG is revealed and rectified from not only frequency dynamics but also rotor angle stability perspective. The simulation of a generic two-machine system and two-machine infinite bus system are implemented in MATLAB/Simulink. The simulation results verifies that the linearized model of DFIG is effective for frequency study, and conclusion is acquired that the frequency enhancement of DFIG to system should be recognized as "fast power response" instead of providing virtual inertia.

关键词： DFIG inertia response linearized model fast power response

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Gain scheduling model predictive control for a space thermionic nuclear reactor

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NUCLEAR ENGINEERING AND DESIGN 2025年 439卷

作者： Ma, Qian Wang, Kai Sun, Peiwei Wei, Xinyu Xi An Jiao Tong Univ Sch Nucl Sci & Technol Shaanxi Key Lab Adv Nucl Energy & Technol 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Shaanxi Engn Res Ctr Adv Nucl Energy Sch Nucl Sci & Technol 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China East China Univ Technol 418 Guanglan Ave Nanchang 330013 Jiangxi Peoples R China Nucl Power Inst China 328 Changshun Ave Chengdu 610213 Sichuan Peoples R China

Space thermionic nuclear reactor (STNR) has the characteristics of large delay and strong nonlinearity. It is difficult to obtain the satisfied performance with traditional control system. model prediction control (MPC) is adopted in this study. The control law is designed and optimized through the prediction model and objective performance function. The problem of poor control performance of large delay system is solved and fast regulation is achieved. The model predictive controllers are designed at different power levels. Gain scheduling method is utilized to improve the tracking accuracy of the nonlinear system. This approach enables stable operation of STNRs across the full-power range. It is shown from the simulation analysis under the representative operational scenarios that the model predictive control system based on gain scheduling has smaller overshoot and settling time than the traditional control system. The fluctuations of major parameters are reduced significantly. Therefore, the proposed gain scheduling model predictive control provides a promising strategy to the control of STNR.

关键词： Space thermionic nuclear reactor model predictive control Gain scheduling linearized model

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A combined analytical model for orifice-type and pipe-type air springs with auxiliary chambers in dynamic characteristic prediction

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MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2023年 185卷

作者： Zheng, Yiqian Shangguan, Wen -Bin South China Univ Technol Sch Mech & Automot Engn Guangzhou 510641 Peoples R China

The frequency-domain properties of air springs with an auxiliary chamber are highly dependent on the type of air flow passages. The dynamic characteristics of air springs with different flow passages are so variated that they are modeled separately. This paper aims to develop a combined dynamic characteristic model for both orifice-type and pipe-type air springs, which newly con-siders the viscoelasticity of bellows and the frequency-and amplitude-dependency of air damp-ing. Firstly, experiments are conducted to study the dynamic characteristics of air springs. Then a combined analytical model is developed based on thermodynamic theory. The generation mechanism and criteria for resonance peaks in dynamic stiffness are illustrated. Further, model parameters are identified using the ellipse features of Nyquist diagrams. The predicted stiffness and loss angle of ASAC are compared with measured results for validations. Finally, the calculated results of the proposed model are compared with that of three other common models in the re-ported literature. The results show that the proposed models are more accurate and are generated for both orifice-type and pipe-type air springs.

关键词： Air springs with auxiliary chambers Dynamic characteristics linearized model Orifice Pipe

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Pressure oscillation of an air pocket beneath a water column in a vertical riser

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WATER SCIENCE AND TECHNOLOGY 2021年第1期83卷 173-183页

作者： Qian, Yu Zhu, David Z. Univ Alberta Dept Civil & Environm Engn Edmonton AB Canada Ningbo Univ Sch Civil & Environm Engn Ningbo Peoples R China

Storm geysers have received significant attention lately due to its more frequent occurrences and the induced severe local flooding and infrastructure damages. Previous studies suggested that the air pocket pressure oscillated during geyser events especially in rapid filling process, but only the peak values were studied and the oscillation period was not discussed in detail. In this paper, a theoretical model was developed focusing on the period of the pressure oscillation induced by the expansion/compression of the air pocket below a water column in a vertical riser with film flow. It was found that the oscillation period was a function of the initial air pocket volume, initial air pocket pressure head, the riser diameter, and the initial water column length. The oscillation period increased with the air pocket pressure head and the air pocket volume, but decreased with the riser diameter and the polytropic coefficient. The oscillation period increased then decreased with an increasing water column length. Further, when considering the film flow along the riser, the oscillation period decreased slightly from the analytical solution. It was also found that the inflow rate change did not significantly influence the oscillation period.

关键词： air-water flow analytical solution linearized model pressure oscillation storm geyser

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An L² approach to viscous flow in the half space with free elastic surface

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JOURNAL OF ELLIPTIC AND PARABOLIC EQUATIONS 2021年第2期7卷 601-621页

作者： Farwig, Reinhard Schmidt, Andreas Univ Technol Dept Math D-64289 Darmstadt Germany

We consider a linearized fluid-structure interaction problem, namely the flow of an incompressible viscous fluid in the half space R-+(n) such that on the lower boundary a function h satisfying an undamped Kirchhoff-type plate equation is coupled to the flow field. Originally, h describes the height of an underlying nonlinear free surface problem. Since the plate equation contains no damping term, this article uses L-2-theory yielding the existence of strong solutions on finite time intervals in the framework of homogeneous Bessel potential spaces. The proof is based on L-2-Fourier analysis and also deals with inhomogeneous boundary data of the velocity field on the "free boundary" x(n) = 0.

关键词： Undamped Kirchhoff-type plate equation free surface flow linearized model

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A fast three-phase synchronization technique with parallel structure

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ENERGY REPORTS 2020年 6卷 1114-1122页

作者： Li, Jinbo Wang, Qin Hu, Yinfeng Sun, Zhifeng Xiao, Lan Wang, Yupei Nanjing Univ Aeronaut & Astronaut Coll Automat Engn Nanjing 210000 Peoples R China

For many grid-connected equipment, the phase and frequency of grid voltage are crucial synchronization information. A phase-locked loop (PLL) is usually employed to obtain the information. In distorted grid, adding additional filter is a convenient and effective approach to enhance the harmonic rejection capability of the PLL. Most filters cannot simultaneously block the inter-harmonics, sub-harmonics and other order harmonics. Adaptive notch filter (ANF) can accomplish such task, since multiple ANFs can be flexibly cascaded. Generally, ANFs works as an in-loop filter in a PLL. When the notch frequency of an ANF is very low or multiple ANFs are cascaded in the control loop, the slowing down of the PLL response speed may be unacceptable in some applications. To deal with this problem, this paper proposes a parallel structure for the ANF-PLL to improve the response speed. In the proposed structure, a group of ANFs are placed in a front-stage synchronous reference frame and work as a prefilter, and a conventional ANF-PLL is used as a parallel frequency feedback loop (FFL). The effectiveness of this technique is verified through experimental results. (C) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the scientific committee of the 7th International Conference on Power and Energy Systems Engineering, CPESE 2020.

关键词： Adaptive notch filter (ANF) Phase-locked loop (PLL) Prefilter linearized model Harmonic voltage

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Understanding post-COVID inflation dynamics

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JOURNAL OF MONETARY ECONOMICS 2023年第Sup期140卷 101-118页

作者： Harding, Martin Linde, Jesper Trabandt, Mathias Bank Canada 234 Wellington St Ottawa ON K1A 0G9 Canada Int Monetary Fund Washington DC 20431 USA Gothenburg Univ Gothenburg Sweden CEPR Washington DC 20009 USA Goethe Univ Frankfurt Theodor W Adorno Pl 3 D-60323 Frankfurt Germany Halle Inst Econ Res IWH Halle Germany

We propose a macroeconomic model with a nonlinear Phillips curve that has a flat slope when inflationary pressures are subdued and steepens when inflationary pressures are elevated. The nonlinear Phillips curve in our model arises due to a quasi-kinked demand schedule for goods produced by firms. Our model can jointly account for the modest decline in inflation during the Great Recession and the surge in inflation during the post-COVID period. Because our model implies a stronger transmission of shocks when inflation is high, it generates conditional heteroskedasticity in inflation and inflation risk. Hence, our model can generate more sizeable inflation surges due to cost-push and demand shocks than a standard linearized model. Finally, our model implies that the central bank faces a more severe trade-offbetween inflation and output stabilization when inflation is elevated. (c) 2023 Goethe University Frankfurt, International Monetary Fund, Bank of Canada. Published by Elsevier B.V. This is an open access article under the CC BY license (http://***/licenses/by/4.0/

关键词： Inflation dynamics Inflation risk Monetary policy linearized model Nonlinear model Real rigidities

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