Design of a dedicated IFT microcontroller
- Authors: Himunzowa, Grayson
- Date: 2018
- Subjects: Feedback control systems , Automatic control , Engineering design -- Data processing
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/30017 , vital:30809
- Description: The design of a Dedicated IFT Microcontroller originated from the successful implementation of the Iterative Feedback Tuning (IFT) technique into the Digital Signal Processor microcontroller (DSP56F807C) at the University of Cape Town in 2006. However, implementation of the IFT technique on a general-purpose microcontroller is neither optimal, nor a cost-effective exercise, as most of the microcontroller peripherals remain unused, and drain energy for doing nothing. In addition, microcontrollers and DSPs are software-driven devices whose nature is sequential in executing algorithms, and hence have a significant effect on the bandwidth of the closed-loop control. To mitigate the said problem, the design of a Dedicated IFT Microcontroller is proposed in this thesis. To accomplish this goal, the preliminary task was to explore the IFT theory and its applications, followed by a review of the literature on FPGA design methodology for industrial control systems, Microcontroller design principles, and FPGA theory and trends. Furthermore, a survey of electronic design automation (EDA) tools and other application software was also conducted. After the literature review, the IFT was investigated exhaustively by applying it to three types of plants, namely: a DC motor, an oscillatory plant, and an unstable plant. Each of these plants were tested using three types of initial controllers, namely heavilydamped, critically damped and under-damped initial controllers. The plants were also tested by varying the amplitude of the reference signal, followed by using a single-step signal of constant amplitude of one volt. The intention of exploring all of these possibilities was meant to firmly expose the IFT boundaries of applicability, so that the final product would not be vulnerable to unnecessary post-production discoveries. The design methodology adopted in this research was a popular hierarchical and modular top-down procedure, which is an array of abstraction levels that are detailed as: system level, behavioural level, Register-Transfer Level (RTL) and Gate level. At system level, the Dedicated IFT Microcontroller was defined. Thereafter, at behavioural level, the design was simulated using VHDL, created by porting the LabView IFT code to the Xilinx EDA tool. At the RTL, the synthesisable VHDL code utilising fixed-point number representation was written. The compiled bit file was downloaded onto National Instruments (NI) Digital Electronics FPGA Board featuring iii the Spartan 3 series FPGA. This was tested, using a method known as simulation in the hardware. The key contribution of this thesis is the experimental validation of the IFT technique on FPGA hardware as it has never been published before, the work described in chapter four and five. The other contribution is the analysis of 1DOF IFT technique in terms of limitations of applicability for correct implementation, which is the main work of chapter three. This work could be used to explore other computational methods, like the use of floating-point number representation for high resolution and accuracy in numerical computations. Another avenue that could be exploited is Xilinx's recent Vivado methodology, which has the capacity for traditional programming languages like C or C++, as these have in-built floating-point number capability. Finally, out of this work, two papers have already been published by Springer and IEEE Xplore Publishers, and a journal paper has also been written for publication in the Control Systems Technology journal.
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- Date Issued: 2018
A fuzzy logic control system for a friction stir welding process
- Authors: Majara, Khotso Ernest
- Date: 2006
- Subjects: Friction welding , Fuzzy logic , Automatic control , Fuzzy systems
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9594 , http://hdl.handle.net/10948/405 , Friction welding , Fuzzy logic , Automatic control , Fuzzy systems
- Description: FSW is a welding technique invented and patented by The Welding Institute in 1991. This welding technique utilises the benefits of solid-state welding to materials regarded as difficult to weld by fusion processes. The productivity of the process was not optimised as the real-time dynamics of the material and tool changes were not considered. Furthermore, the process has a plastic weld region where no traditional modelling describing the interaction between the tool and work piece is available. Fuzzy logic technology is one of the artificial intelligent strategies used to improve the control of the dynamics of industrial processes. Fuzzy control was proposed as a viable solution to improve the productivity of the FSW process. The simulations indicated that FLC can use feed rate and welding speed to adaptively regulate the feed force and tool temperature respectively, irrespective of varying tool and material change. The simulations presented fuzzy logic technology to be robust enough to regulate FSW process in the absence of accurate mathematical models.
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- Date Issued: 2006
Intelligent gripper design and application for automated part recognition and gripping
- Authors: Wang, Jianqiang
- Date: 2002
- Subjects: Automatic control , Robots, Industrial , Robotics
- Language: English
- Type: Thesis , Doctoral , DTech (Engineering)
- Identifier: vital:10816 , http://hdl.handle.net/10948/102 , Automatic control , Robots, Industrial , Robotics
- Description: Intelligent gripping may be achieved through gripper design, automated part recognition, intelligent algorithm for control of the gripper, and on-line decision-making based on sensory data. A generic framework which integrates sensory data, part recognition, decision-making and gripper control to achieve intelligent gripping based on ABB industrial robot is constructed. The three-fingered gripper actuated by a linear servo actuator designed and developed in this project for precise speed and position control is capable of handling a large variety of objects. Generic algorithms for intelligent part recognition are developed. Edge vector representation is discussed. Object geometric features are extracted. Fuzzy logic is successfully utilized to enhance the intelligence of the system. The generic fuzzy logic algorithm, which may also find application in other fields, is presented. Model-based gripping planning algorithm which is capable of extracting object grasp features from its geometric features and reasoning out grasp model for objects with different geometry is proposed. Manipulator trajectory planning solves the problem of generating robot programs automatically. Object-oriented programming technique based on Visual C++ MFC is used to constitute the system software so as to ensure the compatibility, expandability and modular programming design. Hierarchical architecture for intelligent gripping is discussed, which partitions the robot’s functionalities into high-level (modeling, recognizing, planning and perception) layers, and low-level (sensing, interfacing and execute) layers. Individual system modules are integrated seamlessly to constitute the intelligent gripping system.
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- Date Issued: 2002
Methods for designing and optimizing fuzzy controllers
- Authors: Swartz, Andre Michael
- Date: 2000
- Subjects: Fuzzy sets , Fuzzy systems , Automatic control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5412 , http://hdl.handle.net/10962/d1005226 , Fuzzy sets , Fuzzy systems , Automatic control
- Description: We start by discussing fuzzy sets and the algebra of fuzzy sets. We consider some properties of fuzzy modeling tools. This is followed by considering the Mamdani and Sugeno models for designing fuzzy controllers. Various methods for using sets of data for desining controllers are discussed. This is followed by a chapter illustrating the use of genetic algorithms in designing and optimizing fuzzy controllers.Finally we look at some previous applications of fuzzy control in telecommunication networks, and illustrate a simple application that was developed as part of the present work.
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- Date Issued: 2000