Design of microstrip patch antenna for IEEE 802.16-2004 applications

This thesis presents microstrip patch antenna IEEE 802.16-2004 standards for microwave applications and WiMax. Narrow bandwidth (BW) is the main defect of microstrip patch antenna in wireless communication. The bandwidth can be improved by increasing the substrate thickness, and using air as substrate with low dielectric constant. The antennas were fabricated using FR4 board. Two types of microstrip antenna were used, the first was a single microstrip patch antenna and the second was using an air-gap technique as the dielectric between two antenna boards. The spacer of the air-gap has thickness of 2mm. It was made of wood to separate between the two boards. The transmission line model was used to get the approximate dimension for the design. Different parameters were obtained depending on the simulation and measurement. The Computer Simulations Technology (CST) software was used to simulate the design and the measurement was executed by Vector Network Analyzer (VNA). The two designs were compared to each other and found that some improvements were obtained on the air-gap technique. The bandwidth was improved by 4.51 % with air-gap technique and only 1.02 % with the single patch antenna

Kesan penggunaan e-konkrit berasaskan model needham lima fasa terhadap kesesuaian isi kandungan dan pencapaian pelajar

Kaedah pengajaran memainkan peranan yang penting di dalam meningkatkan tahap kefahaman pelajar. Kaedah pengajaran konvensional sedia ada kurang menarik perhatian pelajar jika ianya hanya melibatkan interaksi satu hala e-Pembelajaran merupakan salah satu kaedah yang boleh digunakan untuk menarik minat dan meningkatkan tahap kefahaman pelajar. Kajian yang dijalankan ini adalah untuk mengkaji kesan e-Konkrit menggunakan Model Needham Lima Fasa terhadap kesesuaian isi kandandungan dan pencapaian..

Automation of ship-to-shore container cranes: A review of state-of-the-art

U radu je prikazan pregled dostignutog stepena razvoja i istraživanja u oblasti automatizacije obalskih kontejnerskih dizalica. Primenom različitih tehnika automatizacije povećava se produktivnost obalskih kontejnerskih dizalica, a sledstveno tome se povećava i efikasnost lučkih terminala kao integralnog dela logističke mreže. U radu je, takođe, prikazan pregled nekih najznačajnijih publikovanih istraživanja iz oblasti upravljanja kod kontejnerskih dizalica, a dati su i principi rada trenutno postojećih uređaja za umirivanje oscilovanja tereta - kontejnera.The paper gives the state-of-the-art of automation of ship-to-shore (STS) container cranes, as the biggest investments in the port terminal system. The automation techniques increase the productivity of the ship-to-shore container crane, and consequently increase the port terminal efficiency, as an integral part of logistic network. The paper also shows a short survey of some most important and recent researches in control of ship-to-shore cranes, and main principles of operation of antis way currently existing devices

Automation of ship-to-shore container cranes: A review of state-of-the-art

U radu je prikazan pregled dostignutog stepena razvoja i istraživanja u oblasti automatizacije obalskih kontejnerskih dizalica. Primenom različitih tehnika automatizacije povećava se produktivnost obalskih kontejnerskih dizalica, a sledstveno tome se povećava i efikasnost lučkih terminala kao integralnog dela logističke mreže. U radu je, takođe, prikazan pregled nekih najznačajnijih publikovanih istraživanja iz oblasti upravljanja kod kontejnerskih dizalica, a dati su i principi rada trenutno postojećih uređaja za umirivanje oscilovanja tereta - kontejnera.The paper gives the state-of-the-art of automation of ship-to-shore (STS) container cranes, as the biggest investments in the port terminal system. The automation techniques increase the productivity of the ship-to-shore container crane, and consequently increase the port terminal efficiency, as an integral part of logistic network. The paper also shows a short survey of some most important and recent researches in control of ship-to-shore cranes, and main principles of operation of antis way currently existing devices

Fuzzy-tuned PID anti-swing control of automatic gantry crane

Anti-swing control is a well-known term in gantry crane control. It is designed to move the payload of gantry crane as fast as possible while the payload swing angle should be kept as small as possible at the final position. A number of studies have proposed anti-swing control using the well-known proportional, integral, derivative (PID) control method. However, PID controllers cannot always effectively control systems with changing parameters. Some studies have also proposed intelligent-based control including fuzzy control. However, the designers often have to face the problem of tuning many parameters during the design to obtain optimum performance. Thus, a lot of effort has to be taken in the design stage. In this paper Fuzzy-tuned PID controller design for anti-swing gantry crane control is presented. The objective is to design a practical anti-swing control which is simple in the design and also robust. The proposed Fuzzy-tuned PID utilizes fuzzy system as PID gain tuners to achieve robust performance to parameters variations in the gantry crane. A complex dynamic analysis of the system is not needed. PID controller is firstly optimized in MATLAB using a rough model dynamic of the system which is identified by conducting a simple open-loop experiment. Then, the PID gains are used to guide the range of the fuzzy outputs of the Fuzzy-tuned PID controllers. The experimental results show that the proposed anti-swing controller has satisfactory performance. In addition, the proposed method is straightforward in the design

The effects of auto-tuned method in PID and PD control scheme for gantry crane system

Gantry crane system is a mechanism in heavy engineering that moves payload such container from one point to another. Generally, experienced operators or experts are required to control manually the gantry position while minimizing the payload vibration or swing oscillation. Therefore, those manpower has to be trained in order to operate the gantry crane system safely and efficiently. Thus, to overcome this problem, a feedback control scheme has been utilized in the system. In this paper, PID and PD controllers are introduced for controlling the trolley displacement and the swing oscillation in the gantry crane system. PID controller is designed for tracking the desired position of the trolley whereas PD controller is implemented to minimize the payload oscillation. The PID and PD parameters are tuned by the auto-tuning method. Simulation results have demonstrated satisfactory response based on control system performances

Robust Input Shaping for Sway Control of an Overhead 3D Crane

This paper presents a robust input shaping control of an overhead 3D crane. Control of a crane in the presence of wind disturbance during payload hoisting is extremely challenging, as hoisting with wind disturbance causes high unwanted payload sway, which makes payload positioning difficult to achieve. Two robust input shaping techniques are presented, the zero vibration derivative-derivative (ZVDD) and extra insensitive (EI) shapers. Simulations using a nonlinear 3D overhead crane model were performed and the performances of the two robust input shapers are compared. In these investigations a wind disturbance force of magnitude 0.3 N is considered for the robustness test, in addition different payload mass were tested. It is predicted that the method can be very useful in reducing the complexity of closed-loop controllers for both tracking and sway control

Fuzzy Control of a Large Crane Structure

The usage of tower cranes, one type of rotary cranes, is common in many industrial structures, e.g., shipyards, factories, etc.  With the size of these cranes becoming larger and the motion expected to be faster and has no prescribed path, their manual operation becomes difficult and hence, automatic closed-loop control schemes are very important in the operation of rotary crane.  In this paper, the plant of concern is a tower crane consists of a rotatable jib that carries a trolley which is capable of traveling over the length of the jib.  There is a pendulum-like end line attached to the trolley through a cable of variable length.  A fuzzy logic controller with various types of membership functions is implemented for controlling the position of the trolley and damping the load oscillations.  It consists of two main types of controllers radial and rotational each of two fuzzy inference engines (FIEs).  The radial controller is used to control the trolley position and the rotational is used for damping the load oscillations.  Computer simulations are used to verify the performance of the controller.  The results from the simulations show the effectiveness of the method in the control of tower crane keeping load swings small at the end of motion

Application of Non-Model Dependent Hybrid Higher-Order Differential Feedback Controller on Crane System

Gantry Crane is a machine used for shipping of goods from one point to another. Speed, accuracy and safety are of paramount importance in gantry crane (GC) operation, but operating GC results in unwanted sway which degrades the accuracy and safety. In this paper, hybrid control schemes are proposed for precise trolley position control and sway suppression in GC systems. Output Based input shaping (OBIS) filter was designed using the output of the system for sway suppression and proportional integral derivative (PID), linear quadratic regulator (LQR), higher order differential feedback (HODF) controllers were incorporated separately for precise trolley position control. Based on Simulation studies and analysis, it was observed that LQR-OBIS controller shown more precise tracking and higher sway reduction control. But HODFC-OBIS is a model-free control schemes hence more robust

LMI based antiswing adaptive controller for uncertain overhead cranes

This paper proposes an adaptive anti-sway controller for uncertain overhead cranes. The state-space model of the 2D overhead crane with the system parameter uncertainties is shown firstly. Next, the adaptive controller which can adapt with the system uncertainties and input disturbances is established. The proposed controller has ability to move the trolley to the destination in short time and with small oscillation of the load despite the effect of the uncertainties and disturbances. Moreover, the controller has simple structure so it is easy to execute. Also, the stability of the closed-loop system is analytically proven. The proposed algorithm is verified by using Matlab/Simulink simulation tool. The simulation results show that the presented controller gives better performances (i.e., fast transient response, position tracking, and low swing angle) than the state feedback controller when there exist system parameter variations as well as input disturbances