2.0 TECHNICAL APPROACH 



2.1 DESIGN REQUIREMENTS 



The original design requirements stated when the manipulator program was 

 initiated in May 1979 were as follows: 



Objective: To develop a small, lightweight underwater manipulator compat- 

 ible with the requirements of the existing unmanned, free- 

 swimming submersible at NOSC and the existing software struc- 

 tures and algorithms developed by the Massachusetts Institute 

 of Technology (MIT), Man-Machine Systems Laboratory in 

 Cambridge. 



Depth of Operation: 2000 feet 



Degrees of Freedom: Four 



Configuration: Straight arm-pivoted at mounting, 180-degree 



stowage. Wrist rotate, wrist pivot, jaw closure. 



Power: 24-V electric 



Weight: 20 to 25 pounds 



Lift Capability: 30 pounds at full extension, 100 pounds vertical. 



Jaw Type: Grabber-type jaw. 



Electrical Feedback: Position feedback. 



Performance Capability: Pick up small objects. Apply magnetic particle 



inspection techniques. 



These requirements were meant as general design goals and not as absolute 

 requirements for a specific set of tasks. During the design process, the 

 number of degrees of freedom were increased from four to five, and, because of 

 size and weight constraints, the lift capability was reduced to 5 pounds at 

 full extension and 25 pounds vertical. In addition, it became evident that 

 the existing MIT software would have to be modified extensively to accommodate 

 the particular mechanical design geometry of this manipulator and the use of 

 the powerful LSI/11-23 computer system which was later adopted for both the 

 topside and vehicle computers. 



Potential tasks for the manipulator relative to the USGS pipeline and 

 structures inspection for which the EAVE WEST vehicle has been designed are 



1. Positioning a cavitation-erosion cleaning nozzle developed under 

 contract to the USGS R&D program. 



2. Placing a self-contained sensor package at selected positions on a 

 structure. These packages may be attached either mechanically or 

 magnetical ly. 



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