User manual

Barrett Technology, Inc.
BA4-310 System User Manual Version 1.1
56
6 BarrettWrist Cable Maintenance
6.1 General Wrist Cable Circuit Descriptions
The wrist has three distinct cabling circuits: (1) the input transmission right side, (2) the input
transmission left side, and (3) the differential. The input transmission left and right circuits are
stages of gear reduction for the main motors in the base of the wrist. The differential circuit
translates the rotation of the left and right side circuits into the main pitch and roll motion of the
wrist. An exploded view of the entire wrist, shown in Figure 30, outlines the three distinct
cabling circuits.
Each stage of the cabling circuits, except the differential, is made up of one pulley and one
pinion; the pinion having the smaller diameter. In the left and right input circuits, three stages
of reduction are implemented with the pinion of each stage attached to the pulley on the stage
beneath it. In the differential, all mating pairs of pulleys are of identical size resulting in a 1:1
ratio.
Differential Circuit
3rd Sta
g
e Ri
g
ht
2nd Stage Right
1st Stage R
i
ght
3rd Stage Left
2nd Sta
g
e Left
1st Stage Left
Figure 30 - Schematic Diagram of Wrist Cable Circuits
6.2 Helpful Tools & Tips
Re-cabling the BarrettWrist is generally easier if the user is familiar with cabling other
mechanisms such as the BarrettArm. If the user is cabling the BarrettWrist for the first time,
she should read this entire section on wrist cabling before beginning. Make sure that proper