Flexible joint robot (FJR) manipulators can offer many attractive features over rigid manipulators, including light weight, safe operation, and high power efficiency. However, the tracking control of the FJR is challenging due to its inherent problems, such as underactuation, coupling, nonlinearities, uncertainties, and unknown external disturbances. In this article, a terminal sliding mode control (TSMC) is proposed for the FJR system to guarantee the finite-time convergence of the systems output, and to achieve the total robustness against the lumped disturbance and estimation error. By using two coordinate transformations, the FJR dynamics is turned into a canonical form. A cascaded finite-time sliding mode observer (CFTSMO) is constructed to estimate states and lumped disturbance in a finite time based on two measurable states, which not only attenuates the measurement noise but also reduces the peaking phenomenon. The closed-loop stability and the finite-time convergence are rigorously proved by using Lyapunov theorem. The upper bound of the finite convergence time is derived for the reaching and sliding phase. Comparative study is conducted experimentally in real time on the FJR manipulator to verify the effectiveness of the proposed control method.
Nanomaterials have an excellent potential for improving the rheological and tribological properties of lubricating oil. In this study, oleic acid was used to surface-modify nanoparticles to enhance the dispersion and stability of Nanofluid. The surface modification was conducted for inorganic nanoparticles (NPs) TiO₂ and CuO with oleic acid (OA) surfactant, where oleic acid could render the surface of TiO2-CuO hydrophobic. Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM) were used to characterize the surface modification of NPs. The main objective of this study was to investigate the influence of adding modified TiO₂-CuO NPs with weight ratio 1:1 on thermal-physical propertie
... Show MoreThe purpose of the present study is to identify the comprehensive concept of desertion through the Holy Qur’an and to derive some educational implications related to the concept of desertion and its editing. The also aims to explain the images and forms of desertion. The researcher used the qualitative analytical method. The study concluded that the comprehensive concept of desertion was represented in moving from the country of polytheism to the country of Islam, singularity, alienation, and isolation, leaving, repelling and showing off, abandoning the wife in bed, and reciting from the Qur’an recitation, action, and arbitration, insulting, abandoning, delirium, intersection, and manipulation. The researcher has drawn many education
... Show MoreThe chemicals materials were used to study the effect of citric acid, detergents, sodium carbonate, sodium bicarbonate on the vitality of the third stage of mosquito Culex pipiens molestus. The highest larvicidal efficacy was established from citric acid solution followed by detergents solution, sodium carbonate, sodium bicarbonate with (LC50) values 2096, 2715, 13930, 13960 ppm respectively. The concentration of 1000 ppm of citric acid showed a fatal effect on the third stage larvae of mosquitoes which gave a mortality percent of 100% on the second day of the treatment. It was followed by the concentrations of 750 ppm and 500 ppm respectively which caused the death of all larvae on the fifth and sixth days respe
... Show MoreBlends of Polymethyl methacrylate (PMMA)/polyvinyl alcohol (PVA) doped with 2% weight percentage of Sn were prepared with different blend ratios using casting technique. The measurements of A.C conductivity σa.c within the frequency range (25kHz – 5MHz) of undoped and Sn doped PMMA/PVA blends obeyed the relationship σ= Aws were the value of s within the range 0 > s > 1. The results showed that σa.c increases with the increase of frequency. The exponent s showed preceding increase with the increase of PVA content for PMMA/PVA blends doped with Sn. The dielectric constant, dielectric loss, A.C electrical conductivity are varied with the concentration of PVA in the blend and frequency of applied electrical field.
The problem of research is that there are ways to protect and sustain environmentally important sites in Iraq. There are no documentary sources for these sites, such as the natural landscape of natural and important natural resources, which suffer from severe environmental neglect
The aim of this study is to propose mathematical expressions for estimation of the flexural strength of plain concrete members from ultrasonic pulse velocity (UPV) measurements. More than two hundred pieces of precast concrete kerb units were subjected to a scheduled test program. The tests were divided into two categories; non-destructive ultrasonic and bending or rupture tests. For each precast unit, direct and indirect (surface) ultrasonic pulses were subjected to the concrete media to measure their travel velocities. The results of the tests were monitored in two graphs so that two mathematical relationships can be drawn. Direct pulse velocity versus the flexural strength was given in the first relationship while the second equation des
... Show MoreAs the temperature of combustion gases is higher than the melting temperature of the turbine materials, cooling of turbine parts in a gas turbine engine is necessary for safe operation. Cooling methods investigated in this computational study included cooling flow losses. Film-cooling is one typically used cooling method whereby coolant is supplied through holes passage, in present study the holes placed along the camber line of the blade. The subject of this paper is to evaluate the heat transfer that occur on the holes of blade through different
blowing coolant rates. The cases of this study were performed in a low speed wind tunnel with two tip gap at small and large (0.03 and 0.09cm) and multiple coolant flow rates through the fil
The research attempts to identify the pattern of punctuation in contemporary Iraqi poetry through delving into the poetry of an Iraqi poet belonging to the seventieth generation, Namik Abdul Deeb, who belongs to the poets of Arab modernity in general, the research has reached many results, including that the signs of deletion were vocabulary marks any They are located in the center of the poetic singular, or inline markers, which are those that fall within the poetic line of the prose poem separating its vocabulary, or cross-sectional marks located within the poetic passages that are part of the poetic text, and finally text marks which are located within the poetic text and fragmented into Parts. The research also found that the work of
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