2. The vehicle successfully executed various preprogrammed trajectories 

 as modified by the operator. Each trajectory was found to be repeat- 

 able. The vehicle could even be made to return to the side of the 

 tank and to stop when finished with a given run. 



3. Data were obtained for the motor thrust and vehicle speed with re- 

 spect to various programmed values. 



4. Still and motion picture photographic coverage was taken of both the 

 surface and subsurface runs. 



5. The emergency and abort routines operated well. 



6. The system was found to be relatively easy to transport, and it with- 

 stood moving with little difficulty. 



Data Measurements 



Forward thrust was measured to be an average of 38.5 lb when the vehicle 

 was programmed for full speed. 



Forward speed was measured by traversing a 60-ft timed run after the ve- 

 hicle was up to speed. At full speed, the vehicle ran this distance in 19.5 

 s, indicating a maximum vehicle speed of 1.85 knots or 2.1 mi/hr. The speed 

 was found to be independent of whether the vehicle was on the surface or sub- 

 merged. These values are in excess of the maximum 1.5-knot speed predicted 

 during the design phase. 



Problems Encountered 



Problems encountered with the system were minor. They are mentioned pri- 

 marily to aid future designers of robot submersibles. 



STATIC BALANCE. Because it was necessary to place all the batteries in one 

 container to separate them from potential spark-producing electronics, the 

 vehicle tended to list to one side. The problem was easily corrected during 

 the trim and ballasting procedure by merely adding more weight to the other 

 side of the vehicle to counteract the battery weight. Additional foam (figure 

 18) was also added to compensate for the resulting loss of buoyancy. These 

 additional blocks of foam, however, probably increased the vehicle's drag in 

 the water, resulting in a lower vehicle speed. In the future, as new elec- 

 tronic payloads are added to the submersible and more foam is added along the 

 top corners of the frame, this problem is expected to disappear. 



OPERATOR CONSOLE INTERACTION. Fast interaction with the terminal was a 

 problem during the tests; too much time was wasted when it was necessary to 

 reprogram the vehicle. Since that time, however, the trajectory design 

 software has been upgraded not only to allow a selection of preprogrammed 

 tracks, but also to allow development of new patterns based on keyboard input 

 by the operator. In addition, this software has since been modified to accept 

 a much faster operator interaction type of editing rather than the pure 

 prompting-of-questions approach used during the TRANSDEC tests. Reprogramming 

 now requires only 1 min rather than 5 min. Unfortunately, the disadvantage is 

 that the operator must be a little more familiar with the program. 



43 



