The regressor-based adaptive control is useful for controlling robotic systems with uncertain parameters but with known structure of robot dynamics. Unmodeled dynamics could lead to instability problems unless modification of control law is used. In addition, exact calculation of regressor for robots with more than 6 degrees of freedom is hard to be calculated, and the task could be more complex for robots. Whereas the adaptive approximation control is a powerful tool for controlling robotic systems with unmodeled dynamics. The local (partitioned) approximation-based adaptive control includes representation of the uncertain matrices and vectors in the robot model as finite combinations of basis functions. Update laws for the weighting matrices are obtained by the Lyapunov-like design. Therefore, this work is focused function approximation-based control algorithms considering centralized and decentralized approaches. In this work, the following control algorithms are designed: (1) Adaptive hybrid regressor-approximation control. This work attempts to combine the features of both the regressor and the approximation techniques in adaptive control. The regressor technique is a powerful tool for adaptive control of the known structure of modeling while the approximation is useful for estimation of time-varying uncertainty. Therefore, this work proposes adaptive hybrid regressor and approximation control for robots in both free and constrained spaces. The control law consists of three terms: (i) regressor term for initial estimation of the known structure of the robot dynamics, e.g. inertia matrix, Coriolis and centripetal matrix and gravity vector, and (ii) approximation term for estimation of internal and external disturbances resulted from the inexact calculation of regressor matrix and unknown modeling of friction, etc, and (iii) robust term consists of switching sgn(.) function. The control law is designed based on updating the uncertain parameters and the weighting coefficients corresponding to regressor and approximation respectively with position/force tracking purposes. The proposed controller is stable in the sense of Lyapunov stability. (2) Decentralized adaptive partitioned approximation control. Partitioned approximation control is avoided in most decentralized control algorithms; however, it is essential to design feedforward control with improved tracking accuracy. As a result, this work is focused on decentralized adaptive partitioned approximation control for complex robotic systems using the orthogonal basis functions as strong approximators. In essence, the partitioned approximation technique is intrinsically decentralized with some modifications. The proposed decentralized control law consists of three terms: the partitioned approximation-based feedforward term that is necessary for precise tracking, the high gain-based feedback term, and the adaptive sliding gain-based term for compensation of modeling error. The passivity property is essential to prove the stability of local stability of the individual subsystem with guaranteed global stability. Simulation experiments on 2-link robot and 6-link biped robot are performed to prove the effectiveness of the proposed algorithms.
A field experiment was conducted during winter season of 2021 at a research station of college of agricultural engineering sciences, university of Baghdad to determine the response of active fertility percentage and seed yield and its components of faba bean (Vicia faba L. cv. Aguadulce) to distance between plants and spraying of nano and traditional boron. A Randomized Complete Block Design according to split-plots arrangement was used at three replicates. The main plots were three distances between plants (25, 35 and 45 cm), while the sub plots including spraying of distilled water only (control treatment), spraying of boron at a 100 mg L-1 and spraying of nano boron at two concentrations (10 and 15 mg L-1). The results showed that the 25
... Show MoreJournal of Theoretical and Applied Information Technology is a peer-reviewed electronic research papers & review papers journal with aim of promoting and publishing original high quality research dealing with theoretical and scientific aspects in all disciplines of IT (Informaiton Technology
GH and IGF-2 were examined histologically in the present study on adult hens to learn more about the organs’ responses to GH and IGF-2. Cardiac protein synthesis is stimulated by GH and IGF-2, according to microscopic examination. The recent research found a considerable amount of adipose tissue in the cardiac muscle bundles, which is linked to the metabolic process. In addition, GH and IGF-2 were shown to promote protein synthesis and mitosis in liver and gizzard tissues, according to the research. In addition, the apoptosis, regeneration, and secretory activity of gizzard glands are increased by the aforementioned hormones.
The ionospheric characteristics exhibit significant variations with the solar cycle, geomagnetic conditions, seasons, latitudes and even local time. Representation of this research focused on global distribution of electron (Te) and ion temperatures (Ti) during great and severe geomagnetic storms (GMS), their daily and seasonally variation for years (2001-2013), variations of electron and ion temperature during GMS with plasma velocity and geographic latitudes. Finally comparison between observed and predicted Te and Ti get from IRI model during the two kinds of storm selected. Data from satellite Defense Meteorological Satellite Program (DMSP) 850 km altitude are taken for Te, Ti and plasma velocity for different latitudes during great
... Show MoreThis article is an endeavour to highlight the relationship between social media and language evolution. It reviews the current theoretical efforts on communication and language change. The descriptive design, which is theoretically based on technological determision, is used. The assumption behind this review is that the social media plays a significant role in language evolution. Moreover, different platforms of social media are characterized by being the easiest and fastest means of communication. It concludes that the current theoretical efforts have paid much attention to the relationship between social media and language evolution. Such efforts have highlighted the fact that social media platforms are awash with a lot of acronyms, cybe
... Show MoreDental implants are considered a unique treatment alternative for the replacement of missing dentition. There is a strive for materials which increase bone formation in bone implant interface and improve osseointegration to offer immediate loading directly after placement with decreased time. The aim of the study was to assess the effect of nano strontium substituted hydroxyapatite and nano fluorapatite mixture coating of screw shaped commercially pure titanium at the bone implant interface by torque removal test and histological assessment in rabbit tibia. Commercially pure titanium was used to prepare 80 screws that were divided into machined surfaces (CpTi), coated with (SrHA), coated with (FA) and coated with mixture 50%SrHA + 50%FA (mi
... Show MoreThe present study deals with the synthesis of four different azo-azomethine derivatives; this is done by two steps; the first step is diazotization of sulfonamides (sulfanilamide, sulfacetamide, sulfamethoxazole, and sulfadiazine) separately, followed by the second step; the coupling reaction of diazotized compounds with isatin bis-Schiff base named 3-((4-nitrobenzylidene) hydrazono)indolin-2-one. The later one (bis-Schiff base) was synthesized by the reaction of 3-hydrazono-indolin-2-one with p-nitrobenzaldehyde. The chemical structures of newly synthesized compounds were approved on the basis of their FTIR, 1H-NMR, and CHNS elemental analysis data results. The synthesized azo compounds were tested in vitro for their antimicrobial potentia
... Show MoreDesert truffle is considered as a type of Syrian wild fungi that spreads heavily, and it occupies important rank in folk medicine, where its aqueous extract is used for the treatment of some eye and skin illnesses, and people prefer the use of black truffle. This work interested in studying of the most available species; Terfezia claveryi (black) and Tirmania pinoyi (white). The extracts of the two species of truffle were prepared by maceration with water, methanol, and ethanol 70%. Their total phenolic contents (TPC) and total flavonoid contents (TFC) were analyzed using Folin-ciocalteu and Aluminum chloride methods respectively, and their antioxidant activities was tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and
... Show MoreThis research dealt with the analysis of murder crime data in Iraq in its temporal and spatial dimensions, then it focused on building a new model with an algorithm that combines the characteristics associated with time and spatial series so that this model can predict more accurately than other models by comparing them with this model, which we called the Combined Regression model (CR), which consists of merging two models, the time series regression model with the spatial regression model, and making them one model that can analyze data in its temporal and spatial dimensions. Several models were used for comparison with the integrated model, namely Multiple Linear Regression (MLR), Decision Tree Regression (DTR), Random Forest Reg
... Show MoreThe current research reports the preparation and fabrication of the silver paste conductor which is employed as a soldering material for electro – optical components ohmic interconnections. The prepared paste possesses electrical characteristics identical to the ohmic connectors as its observable from resistance – temperature variation. Moreover, the I – V characteristics obeys Ohm’s law and this dependency was further confirmed by the nearly constant capacitance measurements with voltage and frequency. A noticeable improvement in electrical conductivity, compared to the pure silver paste sample, was noted for samples prepared by mixing predetermined weight ratios of brass and copper. Furthermore, stability of electrical resistan
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