Rockwell (ibid.) provides a chart which in- 

 cludes these and their relationship to each 

 other (Fig. 10.38). To limit this discussion, it 

 is assumed that a man and a work object are 

 present and that the man can see the object. 

 Our concern will concentrate on power, the 

 manipulator, the claw or grasping device and 

 control. The basis for this discussion is Table 

 10.8 which presents characteristics of manip- 

 ulators on a variety of submersibles. This 

 table is rather sketchy but is accurate inso- 

 far as manufacturers' brochures and operat- 

 ing manuals allow. To the researcher's dis- 

 tress, a great number of submersible owners 

 state the fact that manipulators are present, 

 but do not list the capabilities in other than 

 broad terms; hence, the many NA (Not 

 Available) annotations. 



K. B. Wilson (34) states that a "true" ma- 

 nipulator can locate and orient its terminal 

 device in any position within its coverage 

 volume, and devices with less ability should 

 be classed as special machines rather than 

 manipulators. If many of the submersibles 

 which have manipulators were required to 

 remain fixed in one spot, their "manipula- 



tors" would become special machines by Wil- 

 son's definition. But the ability of submers- 

 ibles to do everything but operate upside 

 down increases the capability of even the 

 simplest "machines" to locate and orient the 

 terminal device both within and without its 

 area of fixed coverage volume. Consequently, 

 Wilson's strict definition is not rigidly ap- 

 plied. 



Power 



Electric motors and hydraulic pumps are 

 the prime suppliers of manipulator move- 

 ment. If the motors are external to the pres- 

 sure hull they are subject to the same en- 

 vironmental constraints as propulsion mo- 

 tors, and the solutions and trade-offs of AC 

 versus DC are similar. In the case of SEA 

 OTTER, a manually operated pump within the 

 hull pushes hydraulic fluid through the hull to 

 activate its manipulator. NEKTON's man- 

 ipulator obtains all of its motivation directly 

 from the human occupant who actuates the 

 arm from within the pressure huW. JIM, on the 

 other hand, is a human arm within a 



CONTROL 



MAN 



VISUAL DISPLAY 



I I 



I I 



I I 



POWER 



MAN 



COMMAND LOOP 



FEEDBACK LOOP 



ENVIRONMENT 



MANIPULATOR AND 

 TERMINAL DEVICE 



WORK 

 OBJECT 



SENSORS 



1 



MACHINE 



INTERFACE INTERFACE 



Fig. 10.38 Functional relationships in a manned submersible manipulator system. [From Ref. (33)] 



523 



