Enhanced Image-Based Visual Servoing Dealing with Uncertainties

Nowadays, the applications of robots in industrial automation have been considerably increased. There is increasing demand for the dexterous and intelligent robots that can work in unstructured environment. Visual servoing has been developed to meet this need by integration of vision sensors into robotic systems. Although there has been significant development in visual servoing, there still exist some challenges in making it fully functional in the industry environment. The nonlinear nature of visual servoing and also system uncertainties are part of the problems affecting the control performance of visual servoing. The projection of 3D image to 2D image which occurs in the camera creates a source of uncertainty in the system. Another source of uncertainty lies in the camera and robot manipulator's parameters. Moreover, limited field of view (FOV) of the camera is another issues influencing the control performance. There are two main types of visual servoing: position-based and image-based. This project aims to develop a series of new methods of image-based visual servoing (IBVS) which can address the nonlinearity and uncertainty issues and improve the visual servoing performance of industrial robots. The first method is an adaptive switch IBVS controller for industrial robots in which the adaptive law deals with the uncertainties of the monocular camera in eye-in-hand configuration. The proposed switch control algorithm decouples the rotational and translational camera motions and decomposes the IBVS control into three separate stages with different gains. This method can increase the system response speed and improve the tracking performance of IBVS while dealing with camera uncertainties. The second method is an image feature reconstruction algorithm based on the Kalman filter which is proposed to handle the situation where the image features go outside the camera's FOV. The combination of the switch controller and the feature reconstruction algorithm can not only improve the system response speed and tracking performance of IBVS, but also can ensure the success of servoing in the case of the feature loss. Next, in order to deal with the external disturbance and uncertainties due to the depth of the features, the third new control method is designed to combine proportional derivative (PD) control with sliding mode control (SMC) on a 6-DOF manipulator. The properly tuned PD controller can ensure the fast tracking performance and SMC can deal with the external disturbance and depth uncertainties. In the last stage of the thesis, the fourth new semi off-line trajectory planning method is developed to perform IBVS tasks for a 6-DOF robotic manipulator system. In this method, the camera's velocity screw is parametrized using time-based profiles. The parameters of the velocity profile are then determined such that the velocity profile takes the robot to its desired position. This is done by minimizing the error between the initial and desired features. The algorithm for planning the orientation of the robot is decoupled from the position planning of the robot. This allows a convex optimization problem which lead to a faster and more efficient algorithm. The merit of the proposed method is that it respects all of the system constraints. This method also considers the limitation caused by camera's FOV. All the developed algorithms in the thesis are validated via tests on a 6-DOF Denso robot in an eye-in-hand configuration

Composite Blades of Wind Turbine: Design, Stress Analysis, Aeroelasticity, and Fatigue

In this chapter, four main topics in composite blades of wind turbines including design, stress analysis, aeroelasticity, and fatigue are studied. For static analysis, finite element method (FEM) is applied and the critical zone is extracted. Moreover, geometry, layup, and loading of the turbine blades made of laminated composites are calculated and evaluated. Then, according to the stress analysis, critical layer is specified and safety factor is studied based on Tsai-Wu failure criterion. Aeroelasticity is the main source of instability in structures that are subjected to aerodynamic forces. One of the major reasons of instability is the coupling of bending and torsional vibration of flexible bodies, which is known as flutter and considered in this study. Numerical and analytical methods are applied for considering the flutter phenomenon of the blades. For numerical method, the FEM and Joint Aviation Requirements (JAR-23) standard and for analytical method, two-degree freedom flutter and Lagrange’s equations are utilized. Also, lifetime prediction of a horizontal axis wind turbine composite blade is investigated. Accumulated fatigue damage modeling is employed as a damage estimation rule based on generalized material property degradation

The Propagation of Laser Light in Skin by Monte Carlo- Diffusion Method: A Fast and Accurate Method to Simulate Photon Migration in Biological Tissues

INTRODUCTION: Due to the importance of laser light penetration and propagation in biological tissues, many researchers have proposed several numerical methods such as Monte Carlo, finite element and green function methods. Among them, the Monte Carlo method is an accurate method which can be applied for different tissues. However, because of its statistical nature, Monte Carlo simulation requires a large number of photon pockets to be traced, so it is computationally expensive and time- consuming. Although other numerical methods based on the diffusion method are fast, they have two important limitations: first, they are not valid near the bounder of sample and source, and second, their accuracy is less than Monte Carlo method.METHODS: In this study, we combine the accuracy of Monte Carlo method and speed of the diffusion method. This hybrid method is faster than Monte Carlo Method and its accuracy is higher than the diffusion method.RESULTS: We first evaluate this hybrid model and the reflectance of a biological phantom is calculated by Monte Carlo method and this hybrid model. Then the propagation of laser light in the skin tissue has been studied.CONCLUSION: In this study, a combined method based on the Monte Carlo method and the diffuse equation is introduced. This hybrid method is five times faster than Monte Carlo Method, and its accuracy is higher than the diffusion method. The propagation of laser light in skin has also been studied by this hybrid method and its accuracy shows that it can be applied for laser penetration in biological tissues. It seems that this method is good for photo dynamic therapy (PDT) and optical imagin

Compare antioxidant activity from Satureja bachtiarica Bunge essential oils under different extraction methods ( Coventional and innovative techniques)

چکیده : زمینه و هدف :گیاه مرزه بختیاری با نام علمی Satureja bachtiarica Bunge ظرفیت آنتی اکسیدانی بالایی دارد و از آنجا که نوع روش استخراج بر درصد و نوع ترکیبات شیمیایی موجود در اسانس های گیاهی مؤثر است ، تصمیم گرفتیم به مقایسه فعالیت آنتی اکسیدانی اسانس های گیاه مرزه بختیاری حاصل از روش های مختلف استخراج بپردازیم و روش بهینه استخراج را تعیین نماییم . روش بررسی : فعالیت آنتی اکسیدانی و میزان فنل کل اسانس های مرزه بختیاری حاصل از 8 روش مختلف استخراج در دو قالب سنتی ( تقطیر ساده ، تقطیر با بخار ، تقطیر با آب و بخار) و نوین ( روش نفوذ آب به کمک مایکروویو و روش نفوذ آب به کمک مایکروویو و بخار) به روش DPPHو فولین سیوکالتیو تعیین شد . در این مطالعه BHT و Ascorbic acid به عنوان شاهد مثبت به کار برده شدند و داده‌ها درنرم افزار SPSS و با استفاده از آزمون های توصیفی تجزیه و تحلیل شدند . یافته ها: نتایج آزمون های آماری اختلاف معنی داری را در میزان فنل کل و میزان IC50اسانس های حاصل از روش های مختلف استخراج نشان داد (05/0 p ≤). کم­ترین میزان IC50 ( یا بیشترین فعالیت آنتی اکسیدانی ) برابرmg/ml 0.13 ±1.95 مربوط به روش نفوذ آب به کمک مایکروویو و بخار با توان 800 وات بود. در این آزمایش میزان IC50 برای BHTوAscorbic acid به ترتیب mg/ml 0.13 و 0.11 بود . نتیجه گیری : روش نفوذ آب به کمک مایکروویو و بخار با توان 800 وات بهترین روش استخراج اسانس از گیاه مرزه بختیاری با حفظ بالاترین خاصیت آنتی اکسیدانی است

Sliding Mode Control (SMC) of Image‐Based Visual Servoing for a 6DOF Manipulator

The accuracy and stability are two fundamental concerns of the visual servoing control system. This chapter presents a sliding mode controller for image‐based visual servoing (IBVS) which can increase the accuracy of 6DOF robotic system with guaranteed stability. The proposed controller combines proportional derivative (PD) control with sliding mode control (SMC) for a 6DOF manipulator. Compared with conventional proportional or SMC controller, this approach owns faster convergence and better disturbance rejection ability. Both simulation and experimental results show that the proposed controller can increase the accuracy and robustness of a 6DOF robotic system

Metallogenic implications of biotite chemical composition: Sample from Cu-Mo-Au mineralized granitoids of the Shah Jahan Batholith, NW Iran

Abstract Igneous biotite has been analyzed from three I-type calc-alkaline intrusives of the Shah Jahan Batholith in NW Iran, which host several Cu-Mo-Au prospects. The XMg (Mg/Mg+Fe) value of biotite is the most significant chemical factor and the relatively high value of XMg corresponds to relatively high oxidation states of magma (estimated fO2 is mostly 10−12.5 to 10−7.5 bars), which is in good agreement with their host intrusions' setting and related ore occurrences. Based on criteria of AlIV and AlVI values, all studied biotites are primary (AlVI = 0), and based on Altotal values (2.23–2.82 apfu) are in distinctive ranges of mineralized granitoid (Altotal=3.2 apfu). The maximum F content of biotite from the Shah Jahan intrusions is moderately higher than those from some other calc-alkaline intrusions related to Cu-Mo porphyries in the world, and in contrast, Cl content is relatively lower. It is likely a result of primary magmatic vs. secondary hydrothermal origin, as well as the Mg-rich characteristics of the biotite in Shah Jahan. XMg values do not correlate with F and Cl contents of biotite, suggesting that biotite records changes in the F/OH and Cl/OH ratios in coexisting melt/fluids. It is consistent with F-compatible and Cl-incompatible behavior during fractional crystallization of wet calc-alkaline I-type granitoid magma generated at subduction related arc settings. The fugacity ratios of (H2O/HF), (H2O/HCl) and (HF/HCl) magmatic solutions coexisting with biotite illustrate similar trends in the three intrusions, which can be due to parental magma sources and/or indicate occurrence of similar magmatic processes prior to or contemporaneous with exsolution of fluids from melt. The observed trends caused F-depletions and Cl-enrichments within developed magmatic-hydrothermal systems which are one of the essential characteristics of potential Cu-Mo-Au mineralized I-type granitoids

The Effect of Weight Bearing Exercise on Bone Mineral Density of Premenopausal Women

Introduction: Maintaining optimal level of bone mineral density during Premenopause plays an important role in reducing the risk (relative risk of 1.5-3 times mire) of osteoporosis and the subsequent fractures in post-menopausal , therefore aim of this study was to explore the effect of weight-bearing exercise on bone mineral density of premenopausal women. Materials and Methods: In this semi-experimental pretest-posttest with control group design, 20 premenopausal women in the 40 to 45 age range were randomly selected and distributed in two experimental and control groups. Experimental group completed 12 weeks of training, three times a week and 70 minutes per session. Before and after the period of 12 weeks, femoral bone mineral density in all samples were measured by DEXA bone mineral densitometry. We used K-S test for normality assumption, independent sample t-test in within-subject design and paired t-test, ANCOVA for between-subject design. Significance level was 0.05 SPSS-21 was used. Results: The results revealed that 12 week weight bearing exercise resulted in an increase in femoral bone mineral density among participants in experimental group with the significant decrease in control group. Bone mineral density of femoral neck and total hip among the subjects distributed in experimental group, was significantly different from corresponding areas in control group. Discussion: It should be emphasized that exercise is the harmless and appropriate approach to prevent any decrease in bone mineral density in menopausal period which can prevent decrease in bone mineral density due to aging in this period.Key words: Bone Density, Premenopausal, Weight-Bearing Exercis

Investigating the Impact of the Financial Crisis on Conservative Accounting and Transparency of Banking Information

The phenomenon of the financial crisis is not a new phenomenon around the world. The structure of an economy or a set of economies may face a financial crisis. In fact, it is deformation, dimensions, causes and roots of the financial crisis which create a state of change from this crisis. Recently, evidence has shown that the market value of firms subject to bankruptcy is significantly reduced. In this study, the impact of the financial crisis on conservative accounting and transparency of banks in Iran has been studied. After designing the transparency indicators, the transaction information was collected from the Stock Exchange in the five-year period of 2011-2015. The statistical sample consists of 18 banks selected by systematic elimination method, which in total were 90 years-bank. In this research, linear regression and correlation were used to investigate the hypotheses of the research. Eviews software was used to analyze the data and test the hypotheses. What can be said in the overall conclusion of testing the hypotheses is that the financial crisis affects the conservative accounting and transparency of banks