Preferred Language
Articles
/
Zxem7ZEBVTCNdQwCfJy0
Hierarchical Stabilization and Tracking Control of a Flexible-Joint Bipedal Robot Based on Anti-Windup and Adaptive Approximation Control
...Show More Authors

Bipedal robotic mechanisms are unstable due to the unilateral contact passive joint between the sole and the ground. Hierarchical control layers are crucial for creating walking patterns, stabilizing locomotion, and ensuring correct angular trajectories for bipedal joints due to the system’s various degrees of freedom. This work provides a hierarchical control scheme for a bipedal robot that focuses on balance (stabilization) and low-level tracking control while considering flexible joints. The stabilization control method uses the Newton–Euler formulation to establish a mathematical relationship between the zero-moment point (ZMP) and the center of mass (COM), resulting in highly nonlinear and coupled dynamic equations. Adaptive approximation-based feedback linearization control (so-called adaptive computed torque control) combined with an anti-windup compensator is designed to track the desired COM produced by the high-level command. Along the length of the support sole, the ZMP with physical restrictions serves as the control input signal. The viability of the suggested controller is established using Lyapunov’s theory. The low-level control tracks the intended joint movements for a bipedal mechanism with flexible joints. We use two control strategies: position-based adaptive approximation control and cascaded position-torque adaptive approximation control (cascaded PTAAC). The interesting point is that the cascaded PTAAC can be extended to deal with variable impedance robotic joints by using the required velocity concept, including the desired velocity and terms related to control errors such as position, force, torque, or impedance errors if needed. A 6-link bipedal robot is used in simulation and validation experiments to demonstrate the viability of the suggested control structure.

Scopus Clarivate Crossref
View Publication
Publication Date
Wed Oct 28 2020
Journal Name
Iraqi Journal Of Science
Synthesis and Characterization of New Polymers Bearing Tetrazole and Triazole Moieties with Studying their Corrosion Protection of Stainless Steel Surface in Hydrochloric Acid
...Show More Authors

A series of polymers containing1,2,4-triazole  and tetrazole groups in their main chains were synthesized through several steps. Poly(acryloyl hydrazide) was first prepared and then subjected to a hydrazide reaction with phenyl isothiocyanate to give a 1,2,4-triazole ring (2). This polymer was introduced into a reaction with chloro acetylchloride to yield polymer (3), which was refluxed with sodium azide to give polymer (4). Polymer (5) was synthesized by the reaction of polymer (4) with  acrylonitrile in the presence of NH4Cl as a catalyst. Finally, polymer (6) was synthesized by the electrochemical polymerization of polymer (5) using  316L stainless steel as an anti-corrosion coating. Polymer-coated and uncoat

... Show More
View Publication Preview PDF
Scopus (6)
Crossref (3)
Scopus Crossref
Publication Date
Thu Dec 19 2019
Journal Name
Opicon
The Role of Total Quality in Increasing the Productivity of Wheat and Barley Crops and Reducing Costs Using Modern Irrigation Methods in Iraq
...Show More Authors

Most of the world is seeking attention to the agricultural sector, which occupies a distinguished economic center, including Iraq, it is no wonder that the focus is on this sector, especially in developing countries. Descriptive analysis of the sample tables of wheat and barley crops in Iraq showed that adherence to the principles and rules of total quality, including modern irrigation methods (irrigated) has a significant impact in increasing productivity, reducing costs and improving quality compared to traditional irrigation methods, so it became necessary to take agricultural economic units All procedures and means that will help in the application of the rules of total quality to promote the reality of wheat and barley cultivation in I

... Show More
View Publication
Publication Date
Wed Oct 03 2018
Journal Name
University Of Plymouth
Green networking: analyses of power consumption of real and complex IFFT/FFT used in Next-Generation Networks and optical Orthogonal Frequency Division Multiplexing
...Show More Authors

he Orthogonal Frequency Division Multiplexing is a promising technology for the Next Generation Networks. This technique was selected because of the flexibility for the various parameters, high spectral efficiency, and immunity to ISI. The OFDM technique suffers from significant digital signal processing, especially inside the Inverse/ Fast Fourier Transform IFFT/FFT. This part is used to perform the orthogonality/De-orthogonality between the subcarriers which the important part of the OFDM system. Therefore, it is important to understand the parameter effects on the increase or to decrease the FPGA power consumption for the IFFT/FFT. This thesis is focusing on the FPGA power consumption of the IFFT/FFT uses in the OFDM system. This researc

... Show More
Publication Date
Sun Mar 01 2020
Journal Name
International Journal Of Pharmaceutical Research
Eco-friendly and Efficient Composition, Diagnosis Theoretical, kinetic studies, Antibacterial and Anticancer Activities of Mixed Some Metal Complexes of Tridentate Schiff base Ligand
...Show More Authors

Abstract: Mixed ligand Mn(II), Co(II), Ni(II), Cu (II), Zn(II), and Cd(II) complexes with (TMAP) Schiff base ligand and (8HQ) have been composition and analyzed. Diagnosis by, melting point, solubility, Electronic, mass and IR-spectroscopic studies, conductivity elemental, thermoanalytical analysis displayed the forming of mononuclear complexes. Spectral studies results suggest an octahedral system or the metal (II) mixed complexes. The detainments of molar conductance of the mixed complexes in DMF coincide to electrolytic nature of the mixed complexes, consequently, these complexes could be subedited as [M(TMAP)(8Q)(H2O)]nX.yH2O (M=Co(II) and Cu(II) complexes(where n = 1, y = 0 ); [M(TMAP)(8Q)(H2O)]nX.yH2O (M = (where n = 1, y = 1 for Ni(

... Show More
Publication Date
Sat Dec 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
Reflection of mergers and acquisitions in the stock returns and financial performance - An Empirical Study of major international companies to the pharmaceutical industry-
...Show More Authors

Research aims to identify the immediate impact of the announcement of mergers in the stockholders and the feasibility of gain abnormal return and benefiting from  asymmetric information during the announcement that unite 30 days before the announcement of the merger, and announcement day, and 30 days after the announcement of the merger. It was the largest and most important mergers and acquisitions pick that occurred during the global financial crisis, specifically in health care/pharmaceutical industry, Pfizer and Wyeth merger with Novartis acquisition on Alcon. search has adopted three hypotheses: the first hypothesis that ((achieves the target company's shareholders positive abnormal return (or negative) during and befor

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Jan 27 2020
Journal Name
Medico-legal Update
Indications and Adverse Outcomes of Emergency Lower Segment Cesarean Section at 1St and 2Nd Stages of Labor at Al-Elwiya Maternity Teaching Hospital
...Show More Authors

View Publication Preview PDF
Crossref
Publication Date
Sun Jun 02 2019
Journal Name
Baghdad Science Journal
Assessing of Some Toxic Heavy Metals Levels and Using Geo Accumulation Index in Sediment of Shatt Al-Arab and the Iraqi Marine Region
...Show More Authors

Mercury, arsenic, cadmium and lead, were measured in sediment samples of river and marine environmental of Basra governorate in southern of Iraq. Sixteen sites of sediment were selected and distributed along Shatt Al-Arab River and the Iraqi marine environment. The samples were distributed among one station on Euphrates River before its confluence with Tigris River and Shatt Al-Arab formation, seven stations along Shatt Al-Arab River and eight stations were selected from the Iraqi marine region. All samples were collected from surface sediment in low tide time. ICP technique was used for the determination of mercury and arsenic for all samples, while cadmium and lead were measured for the same samples by using Atomic Absorption Spectrosc

... Show More
View Publication Preview PDF
Scopus (8)
Crossref (5)
Scopus Clarivate Crossref
Publication Date
Sun Jan 12 2025
Journal Name
Tikrit Journal Of Administrative And Economic sciences
Analyzing the relationship between human resource management practices and the creative behavior of employees Analytical research in the Ministry of Science and Technology
...Show More Authors

View Publication
Publication Date
Fri Jan 26 2024
Journal Name
Iraqi Journal Of Science
Calculation of The Nuclear Matter Density Distributions and Form Factors For The Ground State of P 12 PBe and P 14 PBe Nuclei
...Show More Authors

The ground state charge, neutron and matter densities for two-neutron halo nuclei P
12
PBe
and P
14
PBe are calculated within a two- frequency shell model approach. In the description of
the halo nuclei it is important to take into account a model space for P
10
PBe and P
12
PBe different
from the two halo neutrons which have to be treated separately in order to explain their
properties. The structures of the halo P
12
PBe and P
14
PBe nuclei show that the dominant
configurations when the two halo neutrons distributed over the 1d shell orbits. Elastic
Coulomb scattering form factors of these two exotic nuclei are also studied through the
combination of the density distributions of

... Show More
View Publication Preview PDF
Publication Date
Mon Oct 28 2019
Journal Name
Iraqi Journal Of Science
Using GIS and Remote Sensing Techniques to Study Water Quality Changes and Spectral Analysis of Tigris River within Mosul City, North of Iraq
...Show More Authors

     The aim of the study is the measuring of changes in the spectral reflectivity water quality, analyzing the seasonal difference of Tigris River within Mosul City in the north of Iraq using Geographic Information Systems (GIS) and remote sensing techniques during the period (2014-2018). For this paper, Satellite images of the 8 Landsat in 2018 for four seasons have been selected in order to study the seasonal changes on the river they took place during 2018.  A total of ten sample datasets were taken at the upstream, midstream and downstream along the Tigris River. This research focuses on analyzing the locational variance of reflectance, analyzing seasonal difference, and finding modeling algal amount change.

... Show More
View Publication Preview PDF
Scopus (8)
Scopus Crossref