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Trajectory planning of mobile manipulators in constrained workspace

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Journal of Harbin institute of Technology(New Series) 2008年第4期15卷 521-524页

作者：付宜利闫庆辉马玉林 Advanced manufacturing Technology Center Harbin Institute of Technology

The cooperative motion planning of nonholonomic wheeled mobile manipulators （WMM） with kinematic redundaney in the constrained workspace was studied. A trajectory planning method combining the probabilistic planning and the solving of inverse kinematic equations was presented. First, the probabilistie planning method was used to determine the guide configurations; then the switching objective function was defined and the path of the end-effector was constructed based on these guide configurations ; finally, the inverse kinematic equations of the WMM were solved using the gradient projection method, and the obstacle avoidance trajectory for joints of the WMM was obtained. Simulation results were given to demonstrate the effectiveness of the proposed method.

关键词： wheeled mobile manipulators constrained workspace probabilistic planning guide configurations trajectory planning

Processing map for hot working of SiC_p/7075 Al composites

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Transactions of Nonferrous Metals Society of China 2010年第4期20卷 668-674页

作者： M.RAJAMUTHAMILSELVAN S.RAMANATHAN R.KARTHIKEYAN Department of manufacturing Engineering Annamalai University Department of Mechanical Engineering Birla Institute of Technology and Sciences

The hot deformation behaviour of 7075 aluminium alloy reinforced with 10%of SiC particles was studied by employing both"processing maps"and microstructural *** composite was characterized by employing optical microscope to evaluate the microstructural transformations and instability *** material investigated was deformed by compression in the temperature and strain rate ranges of 300-500℃and 0.001-1.0 s-1,*** deformation efficiency was calculated by strain rate sensitivity(m)values obtained by hot compression *** power dissipation efficiency and instability parameters were evaluated and processing maps were constructed for strain of *** optimum domains and instability zone were obtained for the *** optimum processing conditions are obtained in the strain rate range of 0.1-0.9 s-1and temperature range of 390-440 ℃with the efficiency of 30%.

关键词： hot deformation processing maps recrystallization flow instability

Optimizing the Pulsed Current Gas Tungsten Arc Welding Parameters

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Journal of Materials Science & Technology 2006年第6期22卷 821-825页

作者： M.Balasubramanian V.Jayabalan V. Balasubramanian Department of Production Engineering Sathyabama Institute of Science and TechnologyIndia Department of manufacturing Engineering Anna UniversityIndia Department of manufacturing Engineering Annamalai UniversityIndia

The selection of process parameter in the gas tungsten arc （GTA） welding of titanium alloy was presented for obtaining optimum grain size and hardness. Titanium alloy （Ti-6Al-4V） is one of the most important non-ferrous metals which offers great potential application in aerospace, biomedical and chemical industries, because of its low density （4.5 g/cm^3）, excellent corrosion resistance, high strength, attractive fracture behaviour and high melting point （1678℃）. The preferred welding process for titanium alloy is frequent GTA welding due to its comparatively easier applicability and better economy. In the case of single pass （GTA） welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. Many considerations come into the picture and one needs to carefully balance various pulse current parameters to reach an optimum combination. Four factors, five level, central composite, rotatable design matrix were used to optimize the required number of experimental conditions. Mathematical models were developed to predict the fusion zone grain size using analysis of variance （ANOVA） and regression analysis. The developed models were optimized using the traditional Hooke and Jeeve＇s algorithm. Experimental results were provided to illustrate the proposed approach.

关键词： Pulsed current Gas tungsten arc welding Titanium alloy Design of experiments ANOVA, Hooke and Jeeve's algorithm Grain size Hardness

Influence of hydrogenation on microstructures and microhardness of Ti6Al4V alloy

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中国有色金属学会会刊：英文版 2008年第3期18卷 506-511页

作者：赵敬伟丁桦赵文娟田学锋侯红亮王耀奇 School of Materials and Metallurgy Northeastern University Beijing Aeronautical manufacturing Techno logy Research institute

The microstructures of Ti6Al4V alloy after hydrogenation were investigated by optical microscopy(OM), X-ray diffraction(XRD) and transmission electron microscopy(TEM). The influence of hydrogenation on the hardness of α and β phases was analysed by microhardness testing. The influence of hydrogenation on alloying elements diffusion was studied by electron probe microanalysis(EPMA). The microstructural observation reveals that hydride δ (FCC structure) as well as large number of dislocations precipitate in the specimens with 0.278% and 0.514% hydrogen, and a lot of twins are found in the specimen with 0.514% hydrogen, simultaneously. The result of microhardness testing shows that the hardness of α and β phases increases synchronously with the increase of hydrogen and the hardness increment of β is larger than that of α. According to analysis of EPMA, the diffusion ability of alloy elements Al and V increases after hydrogenation. It is considered that hydrogen solution strengthening and V element diffusion are the main factors causing the hardness of α phase increase with the increase of hydrogen, and the formation of δ hydrides, lattice defects, hydrogen solution strengthening and Al element diffusion jointly cause the hardness of β phase increase with the increasing hydrogen.

关键词：钛铝合金氢化作用氢化物显微硬度固溶强化

A method of manufacturing process modeling based on activity network for large-sized and complex products

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Journal of Harbin institute of Technology(New Series) 2008年第6期15卷 777-780页

作者：吕民佟振博王刚 Advanced manufacturing Technology Center Harbin Institute of Technology

Simulation technique is an efficient approach to realize the planning and scheduling of manufacturing process of products. An appropriate and efficient manufacturing process model is the basis and key of manufacturing process simulation. By analyzing the features of large-sized and complex products, a method of manufacturing process modeling based on activity network is presented and a mapping algorithm of translating BOM/BOP into the manufacturing process model is designed in detail.

关键词： manufacturing process modeling large-sized and complex products workflow modeling

Modeling on Directional Solidification of Solar Cell Grade Multicrystalline Silicon Ingot Casting

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Journal of Shanghai Jiaotong university(Science) 2011年第3期16卷 316-319页

作者：何亮王罡融亦鸣 Computer Aided manufacturing Laboratory Worcester Polytechnic institute

Solar energy is considered as one of the best alternative energy in the *** silicon ingot casting is the main production process for major supply of solar ***,the casting process cannot be understood clearly because of some difficulties,such as enclosed furnace,long cycle time of production and so *** this paper,an integrated model,including casting process analysis,quality prediction and production parameters optimization,is proposed and the preliminary results are *** framework of the proposed model is introduced and the numerical simulation results on the temperature field and grain growth process are also given out and discussed.

关键词： directional solidification multicrvstalline silicon ingot numerical simulation thermal control

Development of processing maps for as-cast ZE41A magnesium alloy

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中国有色金属学会会刊：英文版 2010年第1期20卷 22-27页

作者： S. ANBU SELVAN S. RAMANATHAN R . KARTHIKEYAN B. K. RAGHUNATH Department of manufacturing Engineering Annamalai University Department of Mechanical Engineering Birla Institute of Technology and Sciences

The hot deformation behavior of as-cast ZE41A magnesium alloy was studied by employing both processing maps and microstructural observations. To obtain processing map, hot compression tests were performed over a range of strain rates (0.001-1.0 s-1) and temperatures (250-450 ℃). Power dissipation efficiency (η) and instability parameter [ξ (ε)] were evaluated and processing maps were developed for the strain of 0.5. The dynamic recrystallization (DRX) and instable zones were identified and validated through micrographs. The processing maps can be used to select optimum strain rates and temperatures for effective hot working of the material.

关键词：加工图镁合金热加工温度热变形行为热压缩试验动态再结晶应变率微观结构

Study of Non-Pharmacological Interventions on COVID-19 Spread

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Computer Modeling in Engineering & Sciences 2020年第12期125卷 967-990页

作者： Avaneesh Singh Saroj Kumar Chandra Manish Kumar Bajpai PDPM Indian institute of Information Technology Design and ManufacturingJabalpur482005India

COVID-19 disease has emerged as one of the life threatening threat to the society.A novel beta coronavirus causes *** began as unidentified pneumonia of unknown etiology in Wuhan City,Hubei province in China emerged in December *** vaccine has been produced till *** models are used to study the impact of different measures used to decrease *** models have been designed to estimate the numbers of spreaders in different scenarios in the present *** the present manuscript,three different mathematical models have been proposed with different scenarios,such as screening,quarantine,andNPIs,to estimate the number of virus *** analysis shows that the numbers of COVID-19 patients will be more without screening the peoples coming from other *** every people suffering fromCOVID-19 disease are *** screening and quarantine with NPIs have been implemented to study their impact on the *** has been found that NPI measures can reduce the number of *** NPI measures reduce the spread function’s growth and provide decision makers more time to prepare with in dealing with the disease.

关键词： Coronavirus COVID-19 mathematical modelling epidemic

SEIHCRD Model for COVID-19 Spread Scenarios,Disease Predictions and Estimates the Basic Reproduction Number,Case Fatality Rate,Hospital,and ICU Beds Requirement

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Computer Modeling in Engineering & Sciences 2020年第12期125卷 991-1031页

作者： Avaneesh Singh Manish Kumar Bajpai PDPM Indian institute of Information Technology Design and ManufacturingJabalpur482005India

We have proposed a new mathematical method,the SEIHCRD model,which has an excellent potential to predict the incidence of COVID-19 *** proposed SEIHCRD model is an extension of the SEIR ***-compartments have added death,hospitalized,and critical,which improves the basic understanding of disease spread and *** have studiedCOVID-19 cases of six countries,where the impact of this disease in the highest are Brazil,India,Italy,Spain,the United Kingdom,and the United *** estimating model parameters based on available clinical data,the modelwill propagate and forecast dynamic *** calculates the Basic reproduction number over time using logistic regression and the Case fatality rate based on the selected countries’age-category *** calculates two types of Case fatality rate one is CFR daily,and the other is total *** proposed model estimates the approximate time when the disease is at its peak and the approximate time when death cases rarely occur and calculate how much hospital beds and ICU beds will be needed in the peak days of *** SEIHCRD model outperforms the classic ARXmodel and the ARIMA ***,MAPE,andRsquaredmatrices are used to evaluate results and are graphically represented using Taylor and Target *** result shows RMSE has improved by 56%–74%,and MAPE has a 53%–89%improvement in prediction accuracy.

关键词： COVID-19 coronavirus SIER model SEIHCRD model parameter estimation mathematical model India Brazil United Kingdom United States Spain Italy hospital beds ICU beds basic reproduction number case fatality rate