Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 85-92). Also available via the Internet.

In the experimental ITER fusion reactor, currently under construction in Cadarache, France, components close to the plasma will get activated and contaminated over time. Therefore, these components will need to be maintained remotely in a so called hot cell facility. The maintenance will be executed according to step-by-step procedures, with every procedure meticulously validated and formally described in an Operation Sequence Description (OSD). To support formal validation, OSDs are to be captured in an ITER-dedicated Structured Language (SL), a form of domain specific programming language. The Remote Handling Study Centre (RHSC), located at FOM institute DIFFER, Nieuwegein, The Netherlands, has an ITER Remote Handling Control Room representative setup which connects to a virtual ITER Hot Cell back-end environment. In this setup, Remote Handling maintenance scenarios and procedures can be tested under realistic conditions. In this thesis, a Structured Language for ITER maintenance is proposed, implemented as a prototype to capture several realistic operational sequences from existing projects, and integrated in the RHSC workflow. The Structured Language programs are converted to schedulable tasks, by inferring their resource usage and time duration from the structured task descriptions. These tasks are then scheduled using a proposed set of scheduling heuristics. The resulting schedule is subsequently submitted to many simulated executions, with random variation in the execution time of individual tasks. The variation that is applied in the execution time, is based on representative task execution times was measured for a recent and repetitive set of maintenance tasks performed at JET. It is shown that inserting a certain amount of slack in the schedule improves its robustness. ITER maintenance scheduling should account for uncertainty by including slack in the resulting planning.

This research was initiated to investigate the application of mobile robotics to hazardous waste site characterization, with the specific emphasis of employing the laser-based positioning measurement system developed by Spatial Positioning Systems, inc. (SPSi) for tracking a mobile robot and geographically tagging collected environmental data. The two specific objectives of this work were to design and construct a remotely piloted robotic system which could enter a simulated hazardous waste site and perform some aspect of initial characterization sampling, and to perform a feasibility study on the use of the SPSi system for outdoor mobile robot tracking. A Honda all-terrain vehicle was converted to a robotic test platform incorporating the SPSi system for positioning and a magnetometer for environmental sensing. The digitally-sampled magnetometer output was geographically tagged with sensor position, and transmitted to a remote computer for display and storage. Although the mechanics of integrating the SPSi system and an environmental sensor on a mobile robot were demonstrated, survey attempts with the mobile robot were unsuccessful because the SPSi system was unable to track the robot's movements outdoors on the simulated hazardous waste site. Tracking capability up to a limiting velocity of approximately 0.35 mls (0.8 mph) was demonstrated with the SPSi system. This restrictive limiting velocity as well as various errors later discovered in SPSi's tracking algorithm prevented a successful implementation of the positioning system on the robot. / Master of Science