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Development and Application of dynamic Integrated DIC Material Parameters inversion method for SHPB Tests

EXPERIMENTAL MECHANICS 2024年第7期64卷 995-1003页

作者： Cai, S. Zhao, J. Liu, Z. Fu, Y. Beijing Inst Technol Sch Aerosp Engn Beijing 100081 Peoples R China Inst Flexible Elect Technol Tsinghua Jiaxing 314006 Zhejiang Peoples R China Shanghai Adv Res Inst Shanghai Synchrotron Radiat Facil SSRF Shanghai 201204 Peoples R China

Backgrounddynamic mechanical parameters are significant to study the dynamic evolution, but multiple constitutive parameters are difficult to be measured or calculated directly in various dynamic tests. This paper develops a dynamic integrated digital image correlation (DIC) inversion method to characterize multiple parameters of 2A12-T4 aluminum alloy for the split Hopkinson pressure bar (SHPB) *** transformation is used to construct virtual deformed images based on time-varying images of dynamic impacts and deformation responses of finite element method (FEM). Through imitating the principle of DIC, the image correlation function embedded the Johnson-Cook constitutive parameters is constructed. The optimal constitutive parameters are obtained by the gradient optimization algorithm when the images are most *** dynamic tests of same strain rate, optimal parameters are obtained by substituting multiple experimental images to co-invert. By substituting inversion results into the FEM simulation, the simulated stress-strain curve is obtained. Meanwhile by extracting the stress-strain signals of multiple experiments, the real mean stress-strain curve is obtained. Through the coincidence of two stress-strain curves, the feasibility of dynamic integrated DIC inversion method and the accuracy of the inversion results are *** dynamic inversion method is universal to obtain multiple parameters in various dynamic experiments, which considers the strain rate and time-varying. Besides this method simplifies the inversion process and obtains multiple dynamic parameters more easily.

关键词： dynamic inversion method Integrated digital image correlation Multiple Johnson-Cook parameters

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Unmanned Aerial Vehicle (UAV) Photogrammetry Technology for dynamic Mining Subsidence Monitoring and Parameter inversion: A Case Study in China

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IEEE ACCESS 2020年 8卷 16372-16386页

作者： Zhou Dawei Qi Lizhuang Zhang Demin Zhou Baohui Guo Lianglin China Univ Min & Technol Jiangsu Key Lab Resources & Environm Informat Eng Xuzhou 221116 Jiangsu Peoples R China Xinneng Min Ind Corp Ltd Xinao Grp Ordos City 017000 Peoples R China Xinneng Min Ind Corp Ltd XMIC Ordos City 017000 Peoples R China

This study mainly presents the method for monitoring the surface dynamic subsidence basin (SDSB) caused by underground coal mining and obtaining parameters of mining subsidence (PMS) in the short term by using an unmanned aerial vehicle (UAV) Photogrammetry Technology. The basic ideas and methods are proposed;that is, the two-stage surface digital elevation model (DEM) is obtained in the short term by UAV;The SDSB is obtained through two phases of DEM subtraction;Based on the dynamic inversion method established in this study, the PMS was obtained. The UAV method was used to monitor the Wangjiata coal mine in Inner Mongolia of China three times in three months to obtain the three phases of DEM;we obtained the two phases SDSB by the three phases of DEM subtraction. The accuracy of DEM and SDSB were 118 mm and 121 mm respectively, Although the accuracy cannot fulfill the requirements of mining subsidence, the PMS was obtained by dynamic inversion method of full subsidence basin fitting, which has better resistance to errors;hence, the obtained PMS are reliable. Based on the engineering application, this study concludes that as a new technology, UAV photogrammetry technology can obtain the SDSB of coal mining areas in a short period with reliable PMS. Meanwhile, it has the advantages of low cost, flexible maneuverability, and so on, and overcomes the shortages of traditional observation stations, which has long observation time and high labor intensity, needs to bury fixed measuring points and easily lose them, and just has a small amount of "spot-like" observation data that cannot reflect the deformation characteristics of the whole subsidence basin. Furthermore, it is feasible to apply this method to mining subsidence monitoring and parameter inversion, and it has a great application prospect for the mining area purposes.

关键词： UAV photogrammetry technology surface dynamic subsidence basin parameters of mining subsidence probability integration model dynamic inversion method

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Software ageing process as an evolving dynamic system

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IET SOFTWARE 2020年第6期14卷 702-710页

作者： Jia, Yun-Fei Zhou, Zhi Quan Wu, Renbiao Civil Aviat Univ China Tianjin Key Lab Adv Signal Proc Tianjin 300300 Peoples R China Univ Wollongong Inst Cybersecur & Cryptol Sch Comp & Informat Technol Wollongong NSW 2522 Australia

Software ageing is correlated with available computing resources of the computer system. These available resources evolve with time, reflecting the developing mechanism of the ageing process. This study is the first to consider a degrading computer system as an evolving dynamic system. The authors proposed a non-linear dynamic model of software ageing, where the coefficients are estimated using a dynamic inversion method, and conduct controlled software experiments, where the experimental conditions are controlled to expedite ageing. The model can be used to forecast mutations of resource variables such as the buffer, cache and central processing unit usage, which have a direct impact on software performance. The stability of the model is assessed by the Jacobi matrix method, and the results show that, when part of a resource has become unallocable, the Linux operating system can readjust the resources to keep the system's performance stable. This process repeats until some of the resources are exhausted, when the system will crash or hang. This study provides hints on the ageing mechanism of computer systems, which are rarely reported in the past.

关键词： ageing resource allocation software reliability Linux Jacobian matrices software performance evaluation computing resources computer system dynamic system nonlinear dynamic model dynamic inversion method resource variables central processing unit usage software performance Linux operating system software ageing process Jacobi matrix method

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Design of Robust Controller of Fixed-Wing UAV for Transition Flight

Design of Robust Controller of Fixed-Wing UAV for Transition...

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International Conference on Unmanned Aircraft Systems (ICUAS)

作者： Kohno, Satoshi Uchiyama, Kenji Nihon Univ Dept Aerosp Engn Chiba 2748501 Japan

ISBN: (纸本)9781479923762

We propose the flight control system of a fixed-wing small UAV for a transition flight in consideration of nonlinearity on its dynamics. The control system consists of controllers for translational motion and rotational motion. The effect of its nonlinear dynamics on a control performance cannot be disregarded when designing a flight control system because it is difficult to linearize the motion with consideration of an equilibrium transition between vertical and horizontal flight modes. Moreover, the attitude of the small UAV is particularly affected by disturbances such as a gust of wind. Therefore, we employ the dynamic inversion method to take nonlinearity of the motion into account for a flight control design. A robust controller is applied to control the attitude of the UAV. It is necessary to use an observer based on the disturbance accommodating control (DAC) method to estimate of unknown parameter of nonlinear equations. We present preliminary results of numerical simulations and experiments of the UAV testbed that uses the proposed control system.

关键词： fixed-wing UAV transition flight dynamic inversion method DAC observer

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Design of Flight Control System for Quad Tilt-Wing UAV

Design of Flight Control System for Quad Tilt-Wing UAV

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International Conference on Unmanned Aircraft Systems (ICUAS)

作者： Mikami, Takahito Uchiyama, Kenji Nihon Univ Dept Aerosp Engn Chiba 2748501 Japan

ISBN: (纸本)9781479960101

Aircraft control system is designed to provide adequate stability during transition flight of a quad-tilt wing (QTW) UAV. The dynamic inversion method, which is a linearization method without an approximation algorithm, is applied to a control problem of the UAV, because of strong nonlinearity of its dynamical behavior. The validity of the proposed control system is verified through numerical simulation and experiment.

关键词： QTW-UAV transition flight dynamic inversion method

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Design of Robust Controller of Fixed-Wing UAV for Transition Flight

Design of Robust Controller of Fixed-Wing UAV for Transition...

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International Conference on Unmanned Aircraft Systems

作者： Satoshi Kohno Kenji Uchiyama Department of Aerospace Engineering Nihon University

ISBN: (纸本)9781479923779

关键词： Fixed-wing UAV Transition flight dynamic inversion method DAC observer

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Fault Tolerant Attitude Tracking Control for Mars Entry Vehicles via Takagi-Sugeno Model

Fault Tolerant Attitude Tracking Control for Mars Entry Vehi...

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2014中国制导、导航与控制学术会议

作者： Bo Jiang Huai-Ning Wu Lei Guo Science and Technology on Aircraft Control Laboratory School of Automation Science and Electrical EngineeringBeihang UniversityBeijing 100191China

ISBN: (纸本)9781479946983

In this paper,a fault tolerant fuzzy tracking controller is designed for Mars entry vehicles during the entry phase in the presence of actuator *** original nonlinear attitude dynamics are divided into two subsystems based on the concept of time-scale *** inversion method is employed for the slow kinematic subsystem to give the angular velocity command by taking the attitude command as its *** Takagi-Sugeno (T-S) fuzzy model based control method is applied for the fast kinetic subsystem by taking angular velocity command as its input to derive the desired control torque in the presence of actuator ***,the simulation results are given to demonstrate the effectiveness of the developed method for the Mars entry fault tolerant attitude control problem.

关键词： attitude control entry descent and landing (spacecraft) fault tolerant control fuzzy control torque control Mars entry vehicles T-S fuzzy model based control method Takagi-Sugeno model angular velocity command dynamic inversion method fault tolerant attitude tracking control nonlinear attitude dynamics time-scale decomposition Conferences Navigation

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