3.0 SYSTEM DESCRIPTION 



3.1 GENERAL DESCRIPTION 



The manipulator resulting from the approach described above is shown in 

 fig 4. The outside physical design is relatively smooth and sleek, with few 

 protruding areas susceptible to potential entanglement. The three-finger 

 design allows the manipulation of both small objects, by using the "finger- 

 tips" or ends of the claw (fig 5), and of relatively large objects by using 

 the inner portion of the claw (fig 6). The portions of the manipulator 

 constructed of fiberglass are shown in fig 7 as laid out on the full-size 

 assembly drawing of the arm (fig 8) before final painting. The upper arm 

 segment is filled with syntactic foam to provide buoyancy in the water and 

 reduce the load weight of the manipulator upon itself. The vacant areas in 

 fig 7 are linked together by using the hard black-anodized aluminum underwater 

 motor housing assemblies described in detail in appendixes A and B. The 

 larger housings (appendix A) are used for the shoulder rotation and shoulder 

 pivot. Four smaller motor assembly units (appendix B) are used for the elbow 

 pivot, wrist rotate, and combination wrist pivot/jaw closure. These six 

 motors then provide jaw closure in addition to five degrees of freedom. 



3.2 PERFORMANCE SPECIFICATIONS 



The operation of the manipulator was found to be extremely smooth and 

 quiet. To date, it has been operated by using only a set of switches which 

 individually represent actuation of each motor. Final integration of the unit 

 into a computer-controlled system is planned for FY 1981. 



The manipulator design (fig 8) consists of 



- Shoulder rotation (motor unit I with HDC 1M-100-2 gear). 



- Shoulder pivot (motor unit I with HDC 1M-200-2 gear or inter- 

 changeable 1M-100-2). 



- Upper arm, 15 inches long. 



- Elbow pivot (motor unit II with HDUF 20-160-2 gear). 



- Forearm, 9.75 inches long, which contains a motor unit II (HDUF 

 20-80-2 gear) for wrist rotate. 



- Combination of wrist pivot and individual moveable three-finger- 

 type hand consisting of two motor units II (HDUF 20-80-2 gear). 



- Two claws, 7.25 inches long (wrist to fingertip). 

 Other major features are as follows. 



- Lift capability in fingertip with fully extended arm: 8 pounds in 

 air, 12.5 pounds in salt water. 



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