Development of Localization and Navigation System for an Autonomous Feeding Robot
Date Issued
2011
Date
2011
Author(s)
Chiu, Tzu-Wei
Abstract
This research was to develop an integrated localization and navigation control system of an autonomous feeding robot for shrimp farming. Feeding is a very important process in shrimp farms. An autonomous feeding robot could feed shrimp 24 hours a day to alleviate restrictions by available human labor. The feeding robot must be able to perceive the environment and its own position. While the feeding robot should follow the bank of the shrimp pond, the navigation system should accurately measure the azimuth and bank distance. Two ultrasonic sensors are mounted on a motor-driven base to enable automatic tracking of the pond bank. Therefore the distance of the feeding robot to the bank could be accurately determined even when the robot is more than 45 degrees from the bank. A fuzzy control algorithm using azimuth and bank distance as input guides the feeding robot by adjusting the angle of the rudder to keep the robot to navigate parallel with the bank. Azimuth readings from the electrical compass combined with signals from an inertial measurement unit (IMU) are used to transform the robot local coordinates into global coordinates via Euler coordinates transformation. The electrical compass could accurately calculate azimuth even if it tilts. The IMU uses an UKF algorithm to reduce noise of the gyroscope sensor to eliminate accumulated error. The localization method uses the built-in Doppler function of a GPS to estimate the moving distance of the robot via trapezoidal integral. The result is then combined with the turning angle from the azimuth to determine the x-y coordinates of the robot. The accurate localization of the feeding robot ensures that a spreader on top of the robot could deliver feed to the shrimp pond every 150 cm or set distance to evenly spread the feed in the shrimp pond for best shrimp growth.
Subjects
Localization
navigation
Type
thesis
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