Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 6 Articles
In this paper, the main objective is to identify the parameters of motors, which includes a brushless\ndirect current (BLDC) motor and an induction motor. The motor systems are dynamically\nformulated by the mechanical and electrical equations. The real-coded genetic algorithm (RGA) is\nadopted to identify all parameters of motors, and the standard genetic algorithm (SRGA) and various\nadaptive genetic algorithm (ARGAs) are compared in the rotational angular speeds and fitness\nvalues, which are the inverse of square differences of angular speeds. From numerical simulations\nand experimental results, it is found that the SRGA and ARGA are feasible, the ARGA can effectively\nsolve the problems with slow convergent speed and premature phenomenon, and is more\naccurate in identifying system�s parameters than the SRGA. From the comparisons of the ARGAs in\nidentifying parameters of motors, the best ARGA method is obtained and could be applied to any\nother mechatronic systems....
This paper proposes a solution to controls warm robots in an effort to avoid obstacles, moving to\nthe goal by the method of Null Space based Behavior (NSB) control of an individual in the swarm.\nThis paper also provides the stability analysis of the converging process by investigating the relationship\nbetween single agents, and the analysis result is proved by using the Lyapunov theory.\nFinally, the simulation results in two-dimensional space have confirmed the obtained theoretical\nresults....
Due to several climate changes caused by greenhouse gases and to increasing need for clean\nenergy sources, more attention has been grew to renewable energy sources and wind energy is\none of the most promising energy source in the future. The current paper presents an investigation\nof the wind power potential in Azraq south area, a remote location in the Northeast Badia of\nJordan using real wind speed data. Also, other wind characteristics with the help of one method of\nmeteorological and Weibull are assessed to evaluate of which at a height of 10 m above ground\nlevel and in open area. Long term data (1991-2001) period measured mean wind speed data\nmeasured at 10 m height was analyzed. Based on these data, the highest and the lowest wind\npower potential are in July and December, respectively. Also, it was indicated that the shape and\nscale parameters for Azraq south varied over a wide range. The monthly values of Weibull shape\nparameter k ranged from 1.05 to 4.2 with a mean value of 3.06. While the monthly values of the\nWeibull scale parameter c were in the range of m/s, with a mean value of 4.57 m/s. It was also\nconcluded that the site studied was not suitable for electric wind application in large-scale. It was\nfound that the wind potential of the region could be adequate for non-grid connected electrical\nand mechanical applications, such as wind generators, battery charging and water pumping as\nwell as agricultural applications....
The precipitation hardened CuCrZr alloy is used in fusion machines for the heat sink of intensely cooled plasma facing components (PFC) due to its good thermal and mechanical properties. CuCrZr is a precipitation hardened alloy and its optimal strength is obtained in Solution Annealed (SA) at 980°C + water quenching + Aging (A) at ~480°C, 3 hr. Electron Beam Welding (EBW) is employed. In this paper, investigation on pore formation after EBW of Lap jointed CuCrZr heat flux alloys was carried out. Ground pores are said to be commonly observed in welding of CuCrZr alloys. The extent of ground pores seems to be depends upon welding configuration, impurities in the material, depth of penetration etc. LECO test results reveals that Oxygen content mainly observed in weld region, chances of oxides formation is increased near defect zone. Average oxygen content observed in weld region is higher....
A pillow type computer input device is proposed. The interface is designed to move computer\ncursor as the user expect by using his or her head movement. A supporting and care devices\naround the bed often becomes barriers for the care and assist task for the patient. The proposed\npillow type interface is designed not to disturb the care and assist tasks. The head movement of\nthe user is estimated by the four pressure sensors under the pillow. In order to improve the user friendliness\nof the interface, the pillow is mounted on the sliding mechanism. Due to these pressure\nsensors, rotating head movement around the neck and nodding movement of the head can be\nmeasured quantitatively. Considering the head movement, the computer cursor is moved by using\nthe original algorithm....
This paper deals with the theoretic simulation of a drill bit whirling under conditions of its contact\ninteraction with the bore-hole bottom rock plane. The bit is considered to be an absolutely rigid\nellipsoidal body with uneven surface. It is attached to the lower end of a rotating elastic drill string.\nIn the perturbed state, the bit can roll without sliding on the bore-hole bottom, performing whirling\nvibrations (the model of dynamic equilibrium with pure rolling when maximum cohesive force\ndoes not exceed the ultimate Coulombic friction). To describe these motions, a nonholonomic dynamic\nmodel is proposed, constitutive partial differential equations are deduced. With their use,\nthe whirling vibrations of oblong and oblate ellipsoidal bits are analyzed, the functions of cohesive\n(frictional) forces are calculated. It is shown that the system of elastic drill string and ellipsoidal\nbit can acquire stable or unstable whirl modes with approaching critical Eulerian values by the\nparameters of axial force, torque and angular velocity. The analogy of the found modes of motions\nwith ones of the Celtic stones is established. It is shown that the ellipsoidal bits can stop their\nwhirling vibrations and change directions of their circumferential motions in the same manner as\nthe ellipsoidal Celtic stones do. As this takes place, the trajectories of the oblate ellipsoidal bits are\ncharacterized by more complicated paths and irregularities....
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