A development system for unmanned untethered submersibles
Date
1994
Authors
Wall, Daniel John
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Abstract
This thesis presents a computer-based environment which assists in developing unmanned, untethered submersibles and intelligent controllers which are capable of guiding them. This thesis also describes the use of the development system in a specific application - the development of a vehicle and intelligent controller which together are capable of docking to an underwater dock.
The development system offers a three-stage approach to modelling unmanned. untethered submersibles. In the first stage - source code editing - the designer can change the vehicle dynamics, sensors and controller functions. A block-diagram based design tool (Boeing's EASYS) is provided to ease the task of changing the vehicle dynamics and sensors. The controller design tools take advantage of architectural commonalities between intelligent controllers. These tools include a perception/reasoning/action module, a knowledge base for the physical environment (map) and a knowledge base for general processes (fuzzy inference engine).
The second stage - mission execution - allows the changes made in stage one to be tested in a simulated underwater environment. In this stage, an unmanned. untethered submersible attempts to reach a destination while avoiding obstacles which may be moving. During the mission, the designer can observe the vehicle's state and ensure that the submersible and controller responses are appropriate.
In stage three - mission display - the developer can display the completed mission history from any perspective and at any scale. The history of the completed mission can be animated or represented by line segments.
The submersible and its intelligent controller designed as an example of using this development system are capable of docking to a subsea dock. The controller architecture has one perception/reasoning/action module, one map and one fuzzy inference engine. The submersible has four sensors to sense linear and angular position and velocity. A lookahead sonar senses changes to the vehicle's immediate surroundings, providing the intelligent controller with a way to recognize, assess and prepare for changes in its subsea environment.