Dynamics and control of flexible manipulators

Flexible link manipulators (FLM) are well-known for their light mass and small energy consumption compared to rigid link manipulators (RLM). These advantages of FLM are even of greater importance in applications where energy efficiency is crucial, such as in space applications. However, RLM are still preferred over FLM for industrial applications. This is due to the fact that the reliability and predictability of the performance of FLM are not yet as good as those of RLM. The major cause for these drawbacks is link flexibility, which not only makes the dynamic modeling of FLM very challenging, but also turns its end-effector trajectory tracking (EETT) into a complicated control problem. The major objectives of the research undertaken in this project were to develop a dynamic model for a FLM and model-based controllers for the EETT. Therefore, the dynamic model of FLM was first derived. This dynamic model was then used to develop the EETT controllers. A dynamic model of a FLM was derived by means of a novel method using the dynamic model of a single flexible link manipulator on a moving base (SFLMB). The computational efficiency of this method is among its novelties. To obtain the dynamic model, the Lagrange method was adopted. Derivation of the kinetic energy and the calculation of the corresponding derivatives, which are required in the Lagrange method, are complex for the FLM. The new method introduced in this thesis alleviated these complexities by calculating the kinetic energy and the required derivatives only for a SFLMB, which were much simpler than those of the FLM. To verify the derived dynamic model the simulation results for a two-link manipulator, with both links being flexible, were compared with those of full nonlinear finite element analysis. These comparisons showed sound agreement. A new controller for EETT of FLM, which used the singularly perturbed form of the dynamic model and the integral manifold concept, was developed. By using the integral manifold concept the links’ lateral deflections were approximately represented in terms of the rotations of the links and input torques. Therefore the end-effector displacement, which was composed of the rotations of the links and links’ lateral deflections, was expressed in terms of the rotations of the links and input torques. The input torques were then selected to reduce the EETT error. The originalities of this controller, which was based on the singularly perturbed form of the dynamic model of FLM, are: (1) it is easy and computationally efficient to implement, and (2) it does not require the time derivative of links’ lateral deflections, which are impractical to measure. The ease and computational efficiency of the new controller were due to the use of the several properties of the dynamic model of the FLM. This controller was first employed for the EETT of a single flexible link manipulator (SFLM) with a linear model. The novel controller was then extended for the EETT of a class of flexible link manipulators, which were composed of a chain of rigid links with only a flexible end-link (CRFE). Finally it was used for the EETT of a FLM with all links being flexible. The simulation results showed the effectiveness of the new controller. These simulations were conducted on a SFLM, a CRFE (with the first link being rigid and second link being flexible) and finally a two-link manipulator, with both links being flexible. Moreover, the feasibility of the new controller proposed in this thesis was verified by experimental studies carried out using the equipment available in the newly established Robotic Laboratory at the University of Saskatchewan. The experimental verifications were performed on a SFLM and a two-link manipulator, with first link being rigid and second link being flexible.Another new controller was also introduced in this thesis for the EETT of single flexible link manipulators with the linear dynamic model. This controller combined the feedforward torque, which was required to move the end-effector along the desired path, with a feedback controller. The novelty of this EETT controller was in developing a new method for the derivation of the feedforward torque. The feedforward torque was obtained by redefining the desired end-effector trajectory. For the end-effector trajectory redefinition, the summation of the stable exponential functions was used. Simulation studies showed the effectiveness of this new controller. Its feasibility was also proven by experimental verification carried out in the Robotic Laboratory at the University of Saskatchewan

Survey of Barriers to Rural Women Economic Empowerment in Iran

Women play an indispensable role in farming and in improving the quality of life in rural areas. Also rural women play a key role in agricultural sector production by working with full passion in production of crops right from the soil preparation till post harvest and food security activities in developing countries. In addition, for reaching development and progress goals of developing countries such as Iran, considering women rural ability promotion are vital. Also, the important role of women rural empowerment in promoting more agricultural productivity and development in rural areas is now widely recognized. The purpose of this study was identifying barriers to rural women economic empowerment. A descriptive–correlation survey approach was used in this study. The population consisted of women living in rural areas of Ardabil County. The questionnaire and interview were used for data collection in this study. The researcher developed the survey instrument. Validity of the instrument was established using a panel of experts. Reliability of the instrument for various questions varied from 0.83 to 0.86. Results showed that the most important barriers to rural women economic empowerment are: less skill of women, lack of men confidence to women, Sexuality, much busy to work at home, lack of employment opportunity to rural women, lack support of government from women entrepreneurship, lack of ability of talking in public. By factor analysis, factors for barriers to rural women economic empowerment were reduced to four main factors, named as individual-psychological, economic participation, infrastructure and social-institutional

Survey of Barriers to Rural Women Economic Empowerment in Iran

Women play an indispensable role in farming and in improving the quality of life in rural areas. Also rural women play a key role in agricultural sector production by working with full passion in production of crops right from the soil preparation till post harvest and food security activities in developing countries. In addition, for reaching development and progress goals of developing countries such as Iran, considering women rural ability promotion are vital. Also, the important role of women rural empowerment in promoting more agricultural productivity and development in rural areas is now widely recognized. The purpose of this study was identifying barriers to rural women economic empowerment. A descriptive–correlation survey approach was used in this study. The population consisted of women living in rural areas of Ardabil County. The questionnaire and interview were used for data collection in this study. The researcher developed the survey instrument. Validity of the instrument was established using a panel of experts. Reliability of the instrument for various questions varied from 0.83 to 0.86. Results showed that the most important barriers to rural women economic empowerment are: less skill of women, lack of men confidence to women, Sexuality, much busy to work at home, lack of employment opportunity to rural women, lack support of government from women entrepreneurship, lack of ability of talking in public. By factor analysis, factors for barriers to rural women economic empowerment were reduced to four main factors, named as individual-psychological, economic participation, infrastructure and social-institutional

Investigation of the utilization amount of the metacognitive strategies

The aim of the present research is investigating the application of metacognitive strategies by the high school students in mathematics major in Isfahan, Iran in academic year of 2012-2013. The methodology of this descriptive research was of measurement type, and data collection tool was Dawson & Mackinder’s Questionnaire (2004). The validity of this study was confirmed by the experts of the field. Its reliability was calculated as 0.81 using Alpha- Chronbach Coefficient. Making use of Cochrane’s formula, the sample volume was a number of 369 students, who were selected using the Cluster Random Sampling & Stratified Random Sampling, and the selection was proportional to the volume. To analyze the data, both the descriptive & inferential statistics were used. The results of this study showed that the amount of application of meta-cognitive strategies (planning strategy, control & supervision strategy, regulation strategy) by the high school mathematics students was above average and there was a significant difference between the score collections of the metacognitive strategies in their different dimensions. Keywords: metacognitive strategies, Planning strategies, control & supervision strategies, regulation strategies, high school perio

Depression and anxiety disorders in a sample of facial trauma: a study from Iran

Background: Various studies have shown that such patients are susceptible to psychological problems and poor quality of life. The aim of the present study was to evaluate and compare the prevalence of depression and anxiety disorders and quality of life in a group of facial trauma. Material and Methods: In the present cross-sectional study Hospital Anxiety and Depression Scale (HADS) and Oral Health Impact (OHIP-14) questionnaires were used. In this study, fifty subjects were selected from the patients with maxillofacial traumas based on the judgment of the physicians, referring to hospitals in Kerman and Rafsanjan during 2012-2013. In addition, 50 patients referring to the Dental School for tooth extraction, with no maxillofacial traumas, were included. SPSS 13.5 was used for statistical analysis with two-sample t-test, MantelHaenszel technique, Pearson’s correlation coefficient and chi-squared test. Results: Seven patients with maxillofacial traumas were depressed based on HADS depression scale, with 5 other borderline cases. However, patients referring for surgery or tooth extraction only 2 were depressed and 1 patient was a borderline case. The results showed that patients with maxillofacial traumas had higher rates of depression and anxiety, with significant differences between this group and the other group (P=0.01). The results of the present study showed a significant prelateship between depression severity and confounding factors. The mean of OHIP-14 parameters were 35.51 ±5.2 and 22.3±2.4 in facial trauma and dental surgery groups, respectively, with statistically significant differences (P=0.01). Conclusions: The results of the present study showed depression and anxiety disorders in patients with maxillofacial trauma. The results showed a higher rate of anxiety and anxiety in patients with maxillofacial traumas compared to the control group

Two-Aperture Microfluidic Probes as Flow Dipoles: Theory and Applications

A microfluidic probe (MFP) is a mobile channel-less microfluidic system under which a fluid is injected from an aperture into an open space, hydrodynamically confined by a surrounding fluid, and entirely re-aspirated into a second aperture. Various MFPs have been developed, and have been used for applications ranging from surface patterning of photoresists to local perfusion of organotypic tissue slices. However, the hydrodynamic and mass transfer properties of the flow under the MFP have not been analyzed, and the flow parameters are adjusted empirically. Here, we present an analytical model describing the key transport properties in MFP operation, including the dimensions of the hydrodynamic flow confinement (HFC) area, diffusion broadening, and shear stress as a function of: (i) probe geometry (ii) aspiration-to-injection flow rate ratio (iii) gap between MFP and substrate and (iv) reagent diffusivity. Analytical results and scaling laws were validated against numerical simulations and experimental results from published data. These results will be useful to guide future MFP design and operation, notably to control the MFP "brush stroke" while preserving shear-sensitive cells and tissues

Med Oral Patol Oral Cir Bucal

Abstract Background: Various studies have shown that such patients are susceptible to psychological problems and poor quality of life. The aim of the present study was to evaluate and compare the prevalence of depression and anxiety disorders and quality of life in a group of facial trauma. Material and Methods: In the present cross-sectional study Hospital Anxiety and Depression Scale (HADS) and Oral Health Impact (OHIP-14) questionnaires were used. In this study, fifty subjects were selected from the patients with maxillofacial traumas based on the judgment of the physicians, referring to hospitals in Kerman and Rafsanjan during 2012-2013. In addition, 50 patients referring to the Dental School for tooth extraction, with no maxillofacial traumas, were included. SPSS 13.5 was used for statistical analysis with two-sample t-test, MantelHaenszel technique, Pearson's correlation coefficient and chi-squared test. Results: Seven patients with maxillofacial traumas were depressed based on HADS depression scale, with 5 other borderline cases. However, patients referring for surgery or tooth extraction only 2 were depressed and 1 patient was a borderline case. The results showed that patients with maxillofacial traumas had higher rates of depression and anxiety, with significant differences between this group and the other group (P=0.01). The results of the present study showed a significant prelateship between depression severity and confounding factors. The mean of OHIP-14 parameters were 35.51 ±5.2 and 22.3±2.4 in facial trauma and dental surgery groups, respectively, with statistically significant differences (P=0.01)

A comparative study on the effect of blood collection tubes on stress oxidative markers

Oxidative stress has a major role in disease pathogenesis. However, limited studies have investigated the effect of various sample collection tubes on oxidative biomarkers. The present study aimed to evaluate the effect of different collection tubes on the variation of malondialdehyde (MDA), nitric oxide (NO), total thiol (t-SH), and ferric reducing ability of plasma (FRAP) levels. A total of 35 individuals participated in this study and each collected sample was separated into three different tubes: glass tubes (GTs), plain plastic tubes (PTs), and gel separator tubes (GSTs). The results of PTs and GSTs were compared to those of GTs as the reference tube. The comparison between the means of biomarkers in various tubes indicated that there was no significant difference in MDA results between tubes. In contrast, t-SH and NO content were significantly decreased in GSTs and PTs compared to GTs. However, the Bland-Altman analysis showed an acceptable concordance for the mentioned analytes and the statistically significant differences were not clinically significant for NO, MDA, and t-SH antioxidant parameters. Moreover, the FRAP level was considerably lower in GSTs compared to GTs. Nevertheless, the Bland-Altman analysis showed a high bias percentage for the FRAP assay when using PTs and GSTs. According to the present results, it can be concluded that switching to plastic blood collection tubes or serum separation tubes could influence the FRAP results. However, there was no interference for the interpretation of other antioxidant assays in different types of collection tubes. Hence, it is suggested to use GTs for total antioxidant capacity evaluations, especially the FRAP assay