TECHNICAL APPROACH 



The vehicle system that has emerged in response to the USGS goals and 

 program philosophy is based on a general set of design concepts. These crite- 

 ria were designed to produce a generalized testbed and technology demonstra- 

 tion platform which could be used both as a pipeline and undersea structure 

 inspection vehicle and as a solution for potential ^avy undersea search and 

 inspection problems. Thus, technology transfer in both directions was a basic 

 motivation for the selected approach. 



DEVELOPMENT PHILOSOPHY 



The basic development philosophies used in the design of the vehicle 

 system are as follows: 



Performance Criteria 



1. The vehicle should be capable of operating both with and without a 

 communication link. A testbed was required which operated under both 

 projection and replacement system concepts. 



2. The vehicle should be capable of demonstrating speeds greater than 

 those of a tethered submersible with the same thruster power. This 

 implies that the vehicle be basically free of cable drag and that a 

 long and narrow configuration be adopted to reduce vehicle drag in 

 the forward direction. 



3. The vehicle should be capable of hovering and maneuvering at zero and 

 low to medium speeds. This rules out the use of fin-controlled, 

 torpedo-type stabilization control systems which provide only dynamic 

 stability and do not allow the vehicle to stop and inspect an under- 

 water object in detail. 



4. The vehicle should be capable of operating relatively inexpensively 

 for several test operations and experiments at sea. This implies 

 that the system have an inexpensive rechargeable energy source, which 

 is both reliable and easily maintained. 



Design Flexibility 



1. The vehicle should be mechanically modular to lend itself to the 

 addition of appendages, such as television cameras, side-looking 

 sonars, and other inspection sensors and effectors. This implies the 

 use of a modular open-frame construction that could perhaps later be 

 packaged in a low drag shell or fairing when the system design 

 configuration for an optimal inspection system is finalized. 



2. The vehicle design should contain a modular, easily updated, and ex- 

 pandable software structure that allows expansion from a single 

 computer system to a more sophisticated supervisory-controlled con- 

 figuration with some capability for autonomous operations. This 

 implies the use of modular, block-structured, high-level languages 

 which can be linked to form the required software program. 



