3. The vehicle design should allow the addition of incremental step-by- 

 step improvements to demonstrate the progressively complex near-term 

 advantages of improved performance over existing systems and 

 approaches. 



4. The testbed vehicle should provide a basic system design which is 

 adaptable to a variety of uses. 



Man/Machine Interface 



1. Wherever possible, the vehicle system should incorporate the use of 

 analogic controls and displays to offer the operator a more familiar 

 adaptation to the computer. This implies the use of such approaches 

 as joystick controls and color graphic displays. 



2. The vehicle should be able to interface with the operator by using a 

 combination of direct vehicle control and preprogrammed or autonomous 

 control. The machine does not have to totally replace the operator 

 at all times, but the machine should be capable of replacing the 

 operator during routine functions or for operations such as automatic 

 position holding. 



Cost Consideration 



Total system cost is of utmost importance when considering an untethered, 

 unmanned submersible. If the basic testbed is expensive to reproduce, it will 

 not be an economically viable alternative to existing approaches to underwater 

 inspection. The untethered vehicle will have to be more sophisticated to 

 allow the more complex decision-and-control capability to occur without re- 

 sorting to the use of wide bandwidth communication lengths and direct 

 operator-vehicle interaction at all times. It should, therefore, be config- 

 ured so that it is reliable, maintenance free (if possible), easily amenable 

 to changes and expansion, and adaptable to a variety of uses. 



Operating costs must also be considered as part of the total system cost. 

 One of the main advantages of the untethered approach is elimination of the 

 costs of cable purchases, repair, handling, and replacement. A tethered ve- 

 hicle also involves hidden costs, such as deck space for the cable and cable- 

 handling system, as well as larger crew costs for handling the cable. The 

 underlying objective of the program has, therefore, been to reduce the total 

 system cost to achieve an economically viable approach to underwater inspec- 

 tion of pipelines and structures. 



VEHICLE CONFIGURATIONS FOR VARIOUS MISSIONS 



As a part of this development effort, several different operational 

 scenarios, such as pipeline inspection, structure inspection, implantation of 

 sensors with a small manipulator, and potential Navy search and recovery mis- 

 sions, were considered. Details of the scenarios for the intended offshore 

 uses of the vehicle are in reference 6. It becomes immediately obvious that a 

 single vehicle designed to accommodate all these scenarios would be large, 

 bulky, unwieldy, and impractical. Therefore, the NOSC approach was to design 

 a modular vehicle which was adaptable to various configurations for different 



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