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TEHL analysis of high-speed and heavy-load roller bearing with quasi-dynamic characteristics

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Chinese Journal of Aeronautics 2015年第4期28卷 1296-1304页

作者： Shi Xiujiang Wang Liqin School of mechatronics engineering Harbin Institute of Technology

In this paper, the aero-engine mainshaft roller bearing D1842926 under typical operating conditions is taken as a case study, a new integrated numerical algorithm of quasi-dynamics and thermal elastohydrodynamic lubrication（TEHL） is put forward, which can complete the bearing lubricated analysis from global dynamic performance to local TEHL state and break out of the traditional analysis way carried out independently in their own *** 3-D film thickness distributions with different cases are given through integrated numerical algorithm, meanwhile the minimum film thickness of quasi-dynamic analysis, integrated numerical algorithm and testing are compared, which show that integrated numerical results have good agreements with the testing data, so the algorithm is demonstrated available and can judge the lubrication state more *** parameter effects of operating and structure on pv value, cage sliding rate, TEHL film pressure, thickness and temperature are researched, which will provide an important theoretical basis for the structure design and optimization of aero-engine mainshaft roller bearing.

关键词： Aero-engine mainshaft roller bearing Ellipticity Load Quasi-dynamics:Radial clearance TEHL:Velocity

An inertial parameter identification method of eliminating system damping effect for a six-degree-of-freedom parallel manipulator

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Chinese Journal of Aeronautics 2015年第2期28卷 582-592页

作者： Tian Tixian Jiang Hongzhou Tong Zhizhong He Jingfeng Huang Qitao School of mechatronics engineering Harbin Institute of Technology

A new simple and effective inertial parameter identification method based on sinusoidal vibrations of a six-degree-of-freedom parallel manipulator is proposed. Compared with previously known identification algorithms, the advantages of the new approach are there is no need to design the excitation trajectory to consider the condition number of the observation matrix and the inertial matrix can be accurately defined regardless of the effect of viscous friction. In addition, the use of a sinusoidal exciting trajectory allows calculation of the velocities and accelerations from the measured position response. Simulations show that the new approach has acceptable tolerance of dry friction when using a simple coupling parameter modified formula. The experimental application to the hydraulically driven Stewart platform demonstrates the capability and efficiency of the proposed identification method.

关键词： Hydraulically Identification Inertial parameter Parallel manipulator Sinusoidal vibration

Development of a Drilling and Coring Test-bed for Lunar Subsurface Exploration and Preliminary Experiments

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Chinese Journal of Mechanical engineering 2014年第4期27卷 673-682页

作者： SHI Xiaomeng DENG Zongquan QUAN Qiquan TANG Dewei HOU Xuyan JIANG Shengyuan School of mechatronics engineering Harbin Institute of Technology

Drill sampling has been widely employed as an effective way to acquire deep samples in extraterrestrial exploration. A novel sampling method, namely, flexible-tube coring, was adopted for the Chang＇e mission to acquire drilling cores without damaging stratification information. Since the extraterrestrial environment is uncertain and different from the terrestrial environment, automated drill sampling missions are at risk of failure. The principles of drilling and coring for the lunar subsurface should be fully tested and verified on earth before launch. This paper proposes a test-bed for conducting the aforementioned experiments on earth. The test-bed comprises a rotary-percussive drilling mechanism, penetrating mechanism, drilling medium container, and signal acquisition and control system. For granular soil, coring experiments indicate that the sampling method has a high coring rate greater than 80%. For hard rock, drilling experiments indicate that the percussive frequency greatly affects the drilling efficiency. A multi-layered simulant composed of granular soil and hard rock is built to test the adaptability of drilling and coring. To tackle complex drilling media, an intelligent drilling strategy based on online recognition is proposed to improve the adaptability of the sampling drill. The primary features of this research are the proposal of a scheme for drilling and coring a test-bed for validation on earth and the execution of drilling experiments in complex media.

关键词： drilling and coring device test-bed lunar soil sampling

Influence of Magnetic Reluctances of Magnetic Elements on Servo Valve Torque Motors

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Chinese Journal of Mechanical engineering 2016年第1期29卷 136-144页

作者： LIU Changhai JIANG Hongzhou School of mechatronics engineering Harbin Institute of Technology

The current research of electro-hydraulic servo valves mainly focuses on the vibration, pressure oscillating and source of noise. Unfortunately, literatures relating to the study of the influence of the magnetic reluctances of the magnetic elements are rarely available. This paper aims to analyze the influence of the magnetic reluctances of the magnetic elements on torque motor. Considering these magnetic reluctances ignored in previous literatures, a new mathematical model of servo valve torque motor is developed and proposed based on the fundamental laws of electromagnetism. By using this new mathematical model and the previous models, electromagnetic torque constant and magnetic spring stiffness are evaluated for a given set of torque motor parameters. A computer simulation by using AMESim software is also performed for the same set of torque motor parameters to verify the proposed model. The theoretical results of electromagnetic torque constant and magnetic spring stiffness evaluated by the proposed model render closer agreement with the simulation results than those evaluated by the previous models. In addition, an experimental measurement of the magnetic flux densities in the air-gaps is carried out by using SFL218 servo valve torque motor. Compared with the theoretical results of the magnetic flux densities in the air-gaps evaluated by the previous models, the theoretical results evaluated by the proposed model also show better agreement with the experimental data. The proposed model shows the influence of the magnetic reluctances of the magnetic elements on the servo valve torque motor, and offers modified and analytical expressions to electromagnetic torque constant and magnetic spring stiffness. These modified and analytical expressions could provide guidance more accurately for a linear control design approach and sensitivity analysis on electro-hydraulic servo valves than the previous expressions.

关键词： servo valve torque motor magnetic reluctance electromagnetic torque constant magnetic spring stiffness

Photocarrier radiometry for noncontact evaluation of space monocrystalline silicon solar cell under low-energy electron irradiation

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Chinese Physics B 2015年第9期24卷 536-541页

作者：刘俊岩宋鹏王飞王扬 School of mechatronics engineering Harbin Institute of Technology

A space monocrystalline silicon（c-Si） solar cell under low-energy（〈 1 MeV） electron irradiation was investigated using noncontact photocarrier radiometry（PCR）. Monte Carlo simulation（MCS） was employed to characterize the effect of different energy electron irradiation on the c-Si solar cell. The carrier transport parameters（carrier lifetime, diffusion coefficient, and surface recombination velocities） were obtained by best fitting the experimental results with a theoretical one-dimensional two-layer PCR model. The results showed that the increase of the irradiation electron energy caused a large reduction of the carrier lifetime and diffusion length. Furthermore, the rear surface recombination velocity of the Si：p base of the solar cell at the irradiation electron energy of 1 Me V was dramatically enhanced due to 1 MeV electron passing through the whole cell. Short-circuit current（I sc） degradation evaluated by PCR was in good agreement with that obtained by electrical measurement.

关键词： photocarrier radiometry electron irradiation silicon solar cell

Highly Aligned Ternary Nanofiber Matrices Loaded with MXene Expedite Regeneration of Volumetric Muscle Loss

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Nano-Micro Letters 2024年第4期16卷 269-292页

作者： Moon Sung Kang Yeuni Yu Rowoon Park Hye Jin Heo Seok Hyun Lee Suck Won Hong Yun Hak Kim Dong‑Wook Han Department of Cogno‑mechatronics engineering College of Nanoscience and NanotechnologyPusan National UniversityBusan 46241Republic of Korea Medical Research Institute School of MedicinePusan National UniversityYangsan 50612Republic of Korea Department of Anatomy School of MedicinePusan National UniversityYangsan 50612Republic of Korea engineering Research Center for Color‑Modulated Extra‑Sensory Perception Technology Pusan National UniversityBusan 46241Republic of Korea Department of Biomedical Informatics School of MedicinePusan National UniversityYangsan 50612Republic of Korea Periodontal Disease Signaling Network Research Center and Dental and Life Science Institute School of DentistryPusan National UniversityYangsan 50612Republic of Korea BIO‑IT Fusion Technology Research Institute Pusan National UniversityBusan 46241Republic of Korea Present Address:Osstem Implant Inc. Seoul 07789Republic of Korea

Current therapeutic approaches for volumetric muscle loss(VML)face challenges due to limited graft availability and insufficient *** overcome these limitations,tissue-engineered scaffolds have emerged as a promising *** this study,we developed aligned ternary nanofibrous matrices comprised of poly(lactide-co-ε-caprolactone)integrated with collagen and Ti_(3)C_(2)T_(x)MXene nanoparticles(NPs)(PCM matrices),and explored their myogenic potential for skeletal muscle tissue *** PCM matrices demonstrated favorable physicochemical properties,including structural uniformity,alignment,microporosity,and *** vitro assays revealed that the PCM matrices promoted cellular behaviors and myogenic differentiation of C2C12 ***,in vivo experiments demonstrated enhanced muscle remodeling and recovery in mice treated with PCM matrices following VML *** insights from next-generation sequencing revealed that MXene NPs facilitated protein and ion availability within PCM matrices,leading to elevated intracellular Ca^(2+)levels in myoblasts through the activation of inducible nitric oxide synthase(i NOS)and serum/glucocorticoid regulated kinase 1(SGK1),ultimately promoting myogenic differentiation via the m TOR-AKT ***,upregulated i NOS and increased NO–contributed to myoblast proliferation and fiber fusion,thereby facilitating overall myoblast *** findings underscore the potential of MXene NPs loaded within highly aligned matrices as therapeutic agents to promote skeletal muscle tissue recovery.

关键词： Ti_(3)C_(2)T_(x)MXene nanoparticle Ternary nanofibrous matrices Myogenesis Regeneration of volumetric muscle loss Next generation sequencing

Effects of Al_2O_3 Nano-additive on Performance of Micro-arc Oxidation Coatings Formed on AZ91D Mg Alloy

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Journal of Materials Science & Technology 2014年第10期30卷 984-990页

作者： Yan Wang Dongbo Wei Jie Yu Shichun Di School of mechatronics engineering Harbin Institute of Technology

Ceramic coatings were prepared on AZ91 D Mg alloy by micro-arc oxidation （MAO） in aluminate electrolytes, with Al2O3 nano-additive suspending at different concentrations. Effects of nano-additive concentration on the structure, phase composition, hardness and anti-corrosion property of the MAO coatings were analyzed by scanning electron microscopy, X-ray diffraction, micro-hardness test and electrochemical method, respectively. The results revealed that Al2O3 nano-particles were mostly incorporated into ceramic coating chemically, transferred into MgAl2O4, rather than being trapped mechanically during MAO process. With the increase of Al2O3 concentration, the voltage-time response, content of MgAl2O4, hardness and anti-corrosion property increased. However, when the concentration varied from 10 g/L to 15 g/L, these behaviors and properties changed only a little. This result indicated that, after the concentration of Al2O3 nano-additive reaching 10 g/L, the incorporation of Al2O3 nano-particles turned into a saturation state, due to the complex process during MAO treatment. Therefore, 10 g/L might be a proper concentration for MAO coating to incorporate Al2O3 nano-particles,

关键词： Micro-arc oxidation Al2O3 nano-additive Mg alloy Corrosion Hardness

An aero-engine life-cycle maintenance policy optimization algorithm: Reinforcement learning approach

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Chinese Journal of Aeronautics 2019年第9期32卷 2133-2150页

作者： Zhen LI Shisheng ZHONG Lin LIN School of mechatronics engineering Harbin Institute of Technology

An aero-engine maintenance policy plays a crucial role in reasonably reducing maintenance cost. An aero-engine is a type of complex equipment with long service-life. In engineering,a hybrid maintenance strategy is adopted to improve the aero-engine operational reliability. Thus,the long service-life and the hybrid maintenance strategy should be considered synchronously in aero-engine maintenance policy optimization. This paper proposes an aero-engine life-cycle maintenance policy optimization algorithm that synchronously considers the long service-life and the hybrid maintenance strategy. The reinforcement learning approach was adopted to illustrate the optimization framework, in which maintenance policy optimization was formulated as a Markov decision process. In the reinforcement learning framework, the Gauss–Seidel value iteration algorithm was adopted to optimize the maintenance policy. Compared with traditional aero-engine maintenance policy optimization methods, the long service-life and the hybrid maintenance strategy could be addressed synchronously by the proposed algorithm. Two numerical experiments and algorithm analyses were performed to illustrate the optimization algorithm in detail.

关键词： Aero-engine Hybrid strategy Maintenance policy Optimization algorithm Reinforcement learning

Web Tension Regulation of Multispan Roll-to-Roll System using Integrated Active Dancer and Load Cells for Printed Electronics Applications

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Chinese Journal of Mechanical engineering 2014年第2期27卷 229-239页

作者： ZUBAIR Muhammad PONNIAH Ganeshthangaraj YANG Young Jin CHOI Kyung Hyun Department of mechatronics engineering Jeju National University

The mass production of primed electronics can be achieved by roll-to-roll（R2R） printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output（MISO） regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ± 1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.

关键词： roll-to-roll(R2R)system multispan printed electronics active dancer load cell artificial neural networks tension control,multi-input-single-output(MISO )