1,183 research outputs found
ADVANCED ANTI-SWAY CONTROL FOR OVERHEAD CRANES
This particular project focuses on a complex system whose dynamics are not very
well understood and hence control designs are not straightforward. The project deals
with the control of industrial overhead cranes. The project has the potential of
bringing many rewards to industries, which are concerned with optimising lifting
equipment performance. Such a system will allow these industries to save time and
consequently costs as the volume of loaded and unloaded goods increases. Part of this
project is to model the system surrounding the crane system and then design a suitable
algorithm for load anti-sway purposes.
The objective of this project is to design and implement an intelligent based controller
that can be used to assist a crane operator in the difficult parts of the operation. The
designed controller should give the appropriate control signal to the crane system such
that the time taken to reach the target position is minimised with a zero sway angle at
the destination. Earlier part of the project consisting of analysing and improving if
required the existing 3-D mathematical linear and non-linear crane models. Two
different models have been investigated: one with a constant cable length and the
other with a variable cable length.
The implementation of the controller is based on Fuzzy Logic Control (FLC). Two
types of FLC have been used and compared the Fixed FLC and the FLC based on
Adaptive Neuro Fuzzy Inference System (ANFIS). Heuristic approaches have been
used for tuning the Fixed FLC. Data obtained from the Fixed FLC are then used for
training ANFIS FLC.
The results prove that it is possible to model an off-line expert fuzzy logic controller
for an overhead crane. The controller achieved satisfactorily results for a constant and
a variable rope length with minimal tuning than the fixed fuzzy method. Proposals for
further work are also briefly discussed
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..
Synchronous control of double-containers for overhead crane
The development and wide application of double spreaders overhead cranes have
effectively improved the loading and unloading efficiency of the container terminals.
However, due to the nonlinear time-varying characteristics and parameter perturbation
of the lifting device of the double spreaders, the difficulty of synchronous and
coordinated control of the double spreader overhead crane is increased. In order to solve
the problem of synchronous control of double spreaders overhead cranes, this work
establishes the mathematical model of the double spreaders overhead crane and
proposes two main methods. The controller based on the fuzzy sliding mode method is
established. Fuzzy logic control can effective estimate the parameters of the system,
reduce the chattering of sliding mode control, and improve the performance of its
control. Mean deviation coupling synchronization control combined with sliding mode
control can effectively control the speed error between the two spreaders, so that they
can keep working synchronously. The other controller is established which use fast
non-singular terminal sliding mode control to ensure that the system can converge in a
finite time. The combination of terminal sliding mode control and super twisting
algorithm can enhance the stability of the system.O desenvolvimento e a vasta aplicação de pontes rolantes de duplo espalhamento
tem melhorado a eficiência de carga e descarga dos terminais de contentores. No
entanto devido ao facto das variações não lineares do tempo e a perturbação dos
parâmetros do dispositivo de elevação de duplo espalhamento, é dificultado o controlo
sincronizado e coordenado. Com o objetivo de resolver o problema do controlo
síncrono das pontes rolantes de duplo espalhamento, este projeto usa o modelo
matemático do guindaste de dupla propagação e propõe dois métodos de resolução. O
controlo baseado no método do modo deslizante difuso. O controlo lógico difuso pode
estimar eficazmente os parâmetros do sistema, reduzir a vibração do controlo do modo
deslizante e melhorar o seu desempenho. O control de sincronização do acoplamento
do desvio médio, combinado com o control do modo deslizante que pode controlar
eficazmente o erro de velocidade entre os dois espalhadores, para que o seu trabalho
possa continuar de forma síncrona. O outro controlador usa um controlo rápido e não
singular do modo de deslizamento do terminal para garantir que o sistema possa
convergir num tempo limitado. A combinação do control no modo deslizante do
terminal e do algoritmo de super rotação pode melhorar a estabilidade do sistema
Robust Adaptive Control of 3D Overhead Crane System
In this chapter an adaptive anti-sway controller for uncertain overhead cranes is proposed. The system model including the system uncertainties and disturbances is introduced firstly. Next, the adaptive controller which can guarantee tracking the desired position of the trolley as well as the anti-sway of the load cable is established. In this chapter, the system is proven to be input-to-state stable (ISS) which is supported by Lyapunov technique. The proposed algorithm is verified by using Matlab/Simulink simulation tool. The simulation results shown that the presented controller gives the good performances (i.e., fast transient response, position tracking, and low swing angle) when there exist system parameters variation as well as input disturbances
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
Adaptive fuzzy observer based hierarchical sliding mode control for uncertain 2D overhead cranes
© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. This paper proposes a new approach to robustly control a 2D under-actuated overhead crane system, where a payload is effectively transported to a destination in real time with small sway angles, given its inherent uncertainties such as actuator nonlinearities and external disturbances. The control law is proposed to be developed by the use of the robust hierarchical sliding mode control (HSMC) structure in which a second-level sliding surface is formulated by two first-level sliding surfaces drawn on both actuated and under-actuated outputs of the crane. The unknown and uncertain parameters of the proposed control scheme are then adaptively estimated by the fuzzy observer (FO), where the adaptation mechanism is derived from the Lyapunov theory. More importantly, stability of the proposed strategy is theoretically proved. Effectiveness of the proposed adaptive FO-based HSMC approach was extensively validated by implementing the algorithm in both synthetic simulations and real-life experiments, where the results obtained by our method are highly promising
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
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