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Title: Design of an analog fuzzy robot navigator
Author: El-Khatib, Mohamed Misbah
ISNI:       0000 0001 3442 1733
Awarding Body: University of Strathclyde
Current Institution: University of Strathclyde
Date of Award: 2008
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One of the greatest challenges facing the control research community is to extend ,the domains of application of autonomous robot navigation to the general class of unstructured environments, that is, environments that are generally dynamic, not fully known a priori, and typically unpredictable. The paramount complexity of the sensor-based navigation problem in unstructured environments arises mainly from the uncertainties. Humans can cope very well with uncertain and unpredictable environments, often relying on approximate or qualitative data and. reasoning to make decisions and to accomplish their objectives. In this thesis a novel design of a fuzzy logic controller for real time navigation of a nonholonomic car-like robot in a dynamic environment and its amilog circuit implementation are investigated. A real time navigator for a nonholonomic car-like robot in a dynamic environment IS proposed. The system consists of a Sugeno-type fuzzy motion planner and a modified proportional navigation based fuzzy controller. The system philosophy is inspired by human routing when moving between obstacles based on visual information including the right and left views and he makes already the next step to the goal in the free space. A Sugeno-type fuzzy motion planner of four inputs one output is used to give a free direction to the robot controller. A modified proportional navigation based fuzzy logic controller for real time navigation of a nonholonomic car-like robot in a dynamic environment is proposed. It has intelligent combination of two behaviours to cope with obstacle avoidance as well as approaching a goal using a proportional navigation path accounting for car-like robot kinematics. Other behaviours can be integrated to perform more co.mplex tasks. In order to ensure stability for the proposed navigator, a new practical approach to stabilize fuzzy systems based on adaptive nonlinear feedback is introduced. This new approach can also be used to stabilize a non-linear cqntrol system using a fuzzy' stabilizer in the feedback loop. The fuzzy stabilizer is tuned such that its nonlinearity lies in a bounded sector results using the circle criterion theory. The new approach has been used to ensure stability' of a car-like robot controller. In addition, the idea has been extended to stabilize MIMO systems based on the additively decomposition technique. A new fully CMOS voltage mode analog circuit. design of two-layer fuzzy navigator and the simulation results are presented. The design also includes a new high precision MAX and MIN circuits for fuzzy inference engine block. The analog design of the main blocks of the fuzzy system (fuzzification block, rule evaluation block, and defuzzification block) is introduced. The circuit design and simulation results of the proposed fuzzy motion planner are presented.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available