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November2012

Volume:11, Issue:1, November' 2012


Control and Identification of DC Machine by Neural Networks

Author: Atef S. Al-Mashakbeh

Abstract:

This paper shows the performance of a Backpropagation neural network (BPNN) for off-line identification and control of separately excited DC motor (SEDCM). The choices of process excitation signal, data sampling time, and neural network model structure are investigated by time-domain simulation. Validity of neural networks models are carried out by cross-validation test. Direct inverse control scheme is used. The performance of BPNN controller is investigated based on step response, sharp changes in speed trajectory, sudden loads, and changes in motor parameters. The simulation results shows that BPNN controller has excellent step response, adapt well to sharp instantaneous changes in speed trajectory and load connected to the motor, and adapt to the changes of motor parameters.

(pp. 626-633)                    Download PDF


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In an adjacency matrix which encodes for a directed Hamiltonian path, a non-zero determinant value certifies the existence of a directed Hamiltonian path when no zero rows (columns) and no similar rows (columns) exist in the adjacency matrix

Author: B. Okunoye

Abstract:

The decision version of Directed Hamiltonian path problem is an NP-complete problem which asks, given a directed graph G, does G contain a directed Hamiltonian path? In two separate papers, the author expresses the graph problem as an adjacency matrix and a proof given to show that under two special conditions relating to theorems on the determinant of a square matrix, a non-zero determinant value certifies the existence of a directed Hamiltonian path. Here, a brief note is added to repair a flaw in the proof. The result, as expressed in the paper title is a more defensible proposition.

(pp. 634-636)                    Download PDF

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Tension Force Regulator of Fine-winding Materials

Author: Emad Said Addasi

Abstract:

This paper describes a new method (apparatus) for regulation the tension force of winding thread, which is used in textile industry. The suggested facility is very simple and it does not require a power supply. It consists of metal cylinder, cone, cup filled with liquid, lever, pulley, and other simple components. In this facility the pulley and the lever play the role of the feedback element for the tension force signal. At the same time this lever is used as actuator to improve the tension force of the winding thread. The suggested device is provided by an adjusting element to set the tension force at the required reference value.

(pp. 637-640)                    Download PDF

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Comparative Study Between Unicast (AODV) and Multicast (MAODV) Routing Protocol

Authors: Mrs. Vandna Verma, Ms. Mallika Sharma, Ms. Krishna Gupta

Abstract:

A mobile ad hoc Network is the collection of mobile Nodes that communicate with each other over wireless links. A mobile ad hoc network is a pear to pear wireless Network where nodes can communicate to each other without the use of infrastructure such as access point and base station. In MANET each Node work as a routers and Node cooperate to provide connectivity, operates without centralize administrator routing is always the most significant part of any network .MANET is a highly challenges Network environment due to special character such as decentralization dynamic topology and neighbors based each mobile Node acts as on point and Node when it is the source and destination of the communication and forward packet to other Node when it is an intermediate Node of the root .Routing is difficult in MANET because any node can leave or join the network at any time (nodes are free to move and are independent of each other) so the topology of these types of networks keeps on changing dynamically which results in difficult  routing , so routing is most concerns areas in these networks . In this Minor Project we will perform a comparative study between AODV (Unicast) and MAODV (Multicast) routing protocol   and we will show different performance matrices such as average packet delay ratio getter with varying using different synonyms.

(pp. 641-645)                    Download PDF

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Armature current spiking problem in a BLDC motor and solution: A case study

Authors: Gurumurthy S R, Archana Sharma, Kallol Roy

Abstract:

Key features of the electrical machine used in a flywheel energy storage system are, higher efficiency, higher speed, capability to be operated as motor and generator alternatively. Brush less DC (BLDC) machines has all these features. This machine is used for storing and retrieval of energy stored in the flywheel. To build Flywheel Energy Storage (FES) system, a suitable power converter/controller is required to be designed which meets the requirement of driving BLDC motor while storing the energy and boosting the voltage while harvesting the energy from the flywheel. This power converter/controller is known as Bi-directional Converter (BDC). Such a system was designed, built and tested. The controller uses signals from rotor position sensors for generating the triggering pulses to the power devices. During the testing of the system huge spikes were observed in the motor armature current and the motor could not be taken to desired rated speed. The motor could be run up to only half of the rated speed (i.e. 7500RPM). In depth analysis of the problem was carried out, root cause of the problem was identified, solution was found and implemented. The motor was made to run up to the full speed of 15,000RPM.

(pp. 646-651)                    Download PDF

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