Biped robots have gained much attention for decades. A variety of researches has been conducted to make them able to assist or even substitute for humans in performing special tasks. In addition, studying biped robots is important in order to understand the human locomotion and to develop and improve control strategies for prosthetic and orthotic limbs. Some challenges encountered in the design of biped robots are: (1) biped robots have unstable structures due to the passive joint located at the unilateral foot-ground contact. (2) They have different configuration when switching from walking phase to another. During the singlesupport phase, the robot is under-actuated, while turning into an over-actuated system during the double-support phase. (3) Biped robots have many degrees of freedom (DOFs). (4) Biped robots interact with different unknown environments. Therefore, this work attempts to investigate and resolve different issues encountered in dynamics, walking pattern generators and control of biped robots; the details as follows: • Dynamics Two walking patterns have been modeled using two well-known formulations: Lagrangian and the modified recursive Newton-Euler (N-E) formulations. The first walking pattern moves with 6 DOFs during the single support phase (SSP) changing its configuration with 7 DOFs during the double support phase (DSP) (the stance foot will move directly during the DSP). Whereas the other walking pattern has 6 DOFs during all walking phases (the SSP and the two sub-phases of the DSP); the stance foot will be fixed during the first sub-phase of the DSP. These two walking pattern are different in configuration and number of phases during the DSP. To resolve the problem of over-actuation, a linear transition function is proposed to ensure smooth transition for the biped from the SSP to the DSP and vice versa. If we assume ideal dynamic response, this strategy can resolve the discontinuity in input control torque and ground reaction forces. • Walking pattern generators Two methods have been used to generate walking patterns of biped mechanism which are (1) optimal control theory and (2) center of gravity (COG)-based model. Computational optimal control has been performed to investigate the effects of some imposed constraints on biped locomotion, such as enforcing swing foot to move level to the ground, hip motion with constant height etc. finite difference approach has been used to transcribe infinite dimensional optimal control problem into finite dimensional suboptimal control problem. Then parameter optimization has been used to get suboptimal trajectory of the biped with the imposing different constraints. In general, any artificially imposed constraint to biped locomotion can lead to increase in value of input control torques. On the other hand, suboptimal trajectory of biped robot during complete gait cycle had been accomplished with different cases such that continuous dynamic response occurs. Enforcing the biped locomotion to move with linear transition of zero-moment point (ZMP) during the DSP can lead to more energy consumption. Using the simple COG-based model, a comparative study has been conducted to generate continuous motion for COG of the biped; all these methods depend on linear pendulum model. It has been shown all these methods are equivalent. On the other hand, the effect of foot configuration has been investigated. Foot rotation can improve biped configuration at heel strike by controlling foot angle. In addition, foot motion with impact can give some freedom and uniform biped configuration compared with motion without impact. To compensate for the deviation of ZMP trajectory due to approximate model of the COG, a novel strategy has been proposed to satisfy kinematic and dynamic constraints, as well as singularity condition. A stable motion has been obtained for the target walking patterns. • Low-level control Two control schemes have been proposed based on dynamics formulations which are conventional adaptive control based on local approximation technique and Lagrangian formulation, and virtual decomposition control (VDC) based on local approximation technique and recursive N-E formulation. In the first approach (conventional control), a new representation of dynamic matrices has been coined which is computationally efficient than other representation (sparse-base representation, Kronecker product etc.). Controller structures for the SSP and the DSP have been designed in details. Since adaptive control assumes no prior knowledge of estimated weighting matrices; therefore, zero input control torques could be result in at the beginning of each phase. Consequently, discontinuous dynamic response could result. The VDC is an efficient tool for complex robotic system such as biped robot. Therefore each subsystem (link, joint) has been controlled using adaptive approximation–based VDC. A novel optimization technique has been used to deal with continuous dynamic response; however, using zero initial weighting matrices for estimation dynamic matrices and vectors could result in zero input control at beginning of each walking phases.
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Protection of the oil pipelineswhich extracted from the wells was found to shut the well and prevent the leakage of oil when broken using safety valve. This valve is automatically activated by loss of pressure between the well and pipelines, which take the pressure, signal from hydraulic pressure sensor through pressure control valve which has constant or variable value but it is regulated manually. The manual regulatory process requires the presence of monitoring workers continuously near the wells which are always found in remote areas. In this paper, a smart system has been proposed that work with proportional pressure control valve and also electronic pressure sensor through Arduino controller, which is programmed in a way that satisfie
... Show MoreModern automation robotics have replaced many human workers in industrial factories around the globe. The robotic arms are used for several manufacturing applications, and their responses required optimal control. In this paper, a robust approach of optimal position control for a DC motor in the robotic arm system is proposed. The general component of the automation system is first introduced. The mathematical model and the corresponding transfer functions of a DC motor in the robotic arm system are presented. The investigations of using DC motor in the robotic arm system without controller lead to poor system performance. Therefore, the analysis and design of a Proportional plus Integration plus Divertive (PID) controller is illustrated.
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This study was conducted in the College of Agriculture fields /University of Baghdad, during Autumn 2013. This study was aimed to examine the mortality rate on the all black fly stages of Acaudalerodes rachipora Singh) by the biotic fungus Beuveria bassiana. The results of a preliminary survey showed that the samples of Ziziphus spaina christi were infested by blakflies in Agriculture collage during Autumn seasons of 2013 , the presence of species of black flies A. rachipora on the lower surface of the leaf, the study aimed to study and research the effects of fungus B. bassiana on black fly A. rachipora. After six days of treatment results showed the continued superiority 106 spore / ml trends in the western, southern and
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In every country in the world, there are a number of amputees who have been exposed to some accidents that led to the loss of their upper limbs. The aim of this study is to suggest a system for real-time classification of five classes of shoulder girdle motions for high-level upper limb amputees using a pattern recognition system. In the suggested system, the wavelet transform was utilized for feature extraction, and the extreme learning machine was used as a classifier. The system was tested on four intact-limbed subjects and one amputee, with eight channels involving five electromyography channels and three-axis accelerometer sensor. The study shows that the suggested pattern recognition system has the ability to classify the sho
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Background:Measurement of hemoglobin A1c (A1C) is a renowned tactic for gauging long-term glycemic control, and exemplifies an outstanding influence to the quality of care in diabetic patients.The concept of targets is open to criticism; they may be unattainable, or limit what could be attained, and in addition they may be economically difficult to attain. However, without some form of targeted control of an asymptomatic condition it becomes difficult to promote care at allObjectives: The present article aims to address the most recent evidence-based global guidelines of A1C targets intended for glycemic control in Type 2 Diabetes Mellitus (T2D).Key messages:Rationale for Treatment Targets of A1C includesevidence for microvascular and ma
... Show MoreObjectives: to assess nurses' knowledge toward infection control measures for hepatitis a virus in hemodialysis
units and to detemine the relationship between nurses' knowledge and their demographical characteristics.
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A non-probability `tturposive" sample of (51) nurses, who were working in hemodialysis units were selected
from Baghdad teaching hosphals. The data were collected through the use of constructed questionnaire, which
consists of two parts (I) Demographic data fom that consists of 10 items and (2) Nurses' knowledge form that
consists of 6 sections contain 79 items, by means of direct interview techniq
Inefficient wastewater disposal and wastewater discharge problems in water bodies have led to increasing pollution in water bodies. Pollutants in the river contribute to increasing the biological oxygen demand (BOD), total suspended solids (SS), total dissolved solids (TDS), chemical oxygen demand (COD), and toxic metals render this water unsuitable for consumption and even pose a significant risk to human health. Over the last few years, water conservation has been the subject of growing awareness and concern throughout the world, so this research focused on review studies of researches that studied the importance of water quality of wastewater treated disposal in water bodies and modern technology to management w
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