The speed of fuzzy controllers implemented on dedicated hardware is adequate for control of any physical process, but too slow for todays high-complexity data networks. Defuzzification has been the bottleneck for fast implementations due to the large number of computationally expensive multiplication and division operations. In this thesis, we propose a high-speed fuzzy inferential system based on log-domain arithmetic, which only requires addition and subtraction operations. The system is implemented on a Xilinx Virtex-II FPGA with a processing speed of 67.6 MFLIPS having a maximum combinational path delay of 4.2 ns. It is a clear speedup compared to the reported fastest 50 MFLIPS implementation. A pipelined version of the controller is also implemented, which achieves a speed of 248.7 MFLIPS. Although a small approximation error is introduced, software simulation and hardware implementation on FPGA confirm high similarity of the outputs for control surfaces and a number of second-order plants. / Software Engineering and Intelligent Systems
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:AEU.10048/979 |
| Date | 06 1900 |
| Creators | Razib, Md Ali |
| Contributors | Dick, Scott (Electrical and Computer Engineering), Gaudet, Vincent (Electrical and Computer Engineering), Reformat, Marek (Electrical and Computer Engineering), Amaral, Nelson (Computing Science) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 832122 bytes, application/pdf |
| Relation | Ali Razib, Scott Dick and Vincent Gaudet (2009). Design of a high-speed fuzzy logic controller based on log-domain arithmetic. 39th International Symposium on Multiple-Valued Logic, 139-144. |
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