| Summary: | 碩士 === 國立臺灣海洋大學 === 通訊與導航工程學系 === 101 === This work aims at studying the performance of fuzzy autopilots of different
number of inputs while using the leading mark based visual guidance for
accomplishing small–boat approaching maneuvers. The experiment uses a small FRP
boat as the test platform and the visual guidance schemes adopt the left-right and rear
leading mark concept and a fuzzy logic autopilot is employed to guide the vessel
toward the intended water way. In the proposed approach, three canvas targets are
arranged at left-right and rear position as leading marks on the quayside. These targets
are detected by a Charge Coupled Device (CCD) camera and the resulting image is
processed using a color recognition scheme to accurately detect the location of the
targets in the image by using LabVIEW/Vision Builder AI software. The geometric
centers of these targets are then calculated, and the separation distance between them
are used to compute the deviated heading angle and the deviated position angle
needed as feedback error signals in the adopted autopilots. The autopilot controller
design process can be divided into three parts, the first part uses the deviated heading
angle (θLM), and the ship's deviated position angle (θCR) as two fuzzy inputs. The
second part adopts the deviated heading angle (θLM), the ship's deviated position angle
(θCR) and the ship's position skew angle (θVCR) as three fuzzy inputs. With three fuzzy
inputs, a total of twenty-seven fuzzy rules are generated. A method to simplify the
twenty-seven fuzzy rules was proposed in this study. The third part of the controller
design method is an enhancement of part two. Namely, to combine the deviated
heading angle (θLM), and the ship's deviated position angle (θCR) into one input and the
ship's position skew angle (θVCR) as another input, and a refined two inputs fuzzy logic
controller is proposed. Two kinds of comparisons are made in the experimental
studies. First one was based on the three different types of input controller experiment
comparison studies. The second focused on the comparison of original three-input
controller fuzzy rules experiments and the simplified three-input controller fuzzy rules.
The feasibility of the proposed concept was verified by performing a series of FPR
boat based experiments conducted in the waterways of the NTOU small boat harbor.
The experimental results demonstrate that the proposed fuzzy rules simplification
design is valid, and the left-right and rear leading mark design performs better than
the original left-right mark design, and the proposed enhanced guidance scheme also
out performs the original left-right mark design.
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