Hardware:
- 1 x Alum. Channel - 3" Single Pack
Brushed (ASB-503B)
- 2 x Multi-Purpose Servo Bracket Two Pack
Black (ASB-04) /
Brushed (ASB-04B)
- 1 x "L" Connector Bracket Two Pack
Black (ASB-06) /
Brushed (ASB-06B)
- 1 x "C" Servo Bracket w/ Ball Bearings Two Pack
Black (ASB-09) /
Brushed (ASB-09B)
- 1 x Robot Feet Pair
Black (ARF-01) /
Brushed (ARF-01B)
- 1 x SES Electronics Carrier (EC-02)
- 1 x SSC-32 Servo Controller (SSC-32)
- 4 x HS-422 (57oz.in.) Standard Servo (S422)
Image of Biped BRAT Jr.
Attach a multi-purpose bracket to the foot as shown, using three 2-56 x .188" screws and 2-56 nuts.
| 3 x | 3 x |
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Figure 1.
Attach the "L" bracket to a short "C" bracket as shown, using two 2-56 x .250" screws and 2-56 nuts.
| 2 x | 2 x |
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Figure 2.
Attach a multi-purpose bracket to the "L" bracket as shown, using two 2-56 x .250" screws and 2-56 nuts.
| 2 x | 2 x |
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Figure 3.
Attach the assembly from Step 3 to the multi-purpose bracket on the foot. See figure 4-1 for detailed information.
Figure 4-1.
Figure 4-2.
Your two leg assemblies should look like the image so far.
Figure 5.
To maintain compatibility with our program, the robot legs have to be mechanically aligned. To do this move the servo to its center of rotation using the Bot Board, SSC, or other servo controller or microcontroller. We have set up a tutorial to guide you through this step. If you are using a different microcontroller, consult your electronics documentation for help with this step.
Note, centering a servo simply requires generating a 1.5mS positive going pulse that repeats every 20mS.
Figure 6.
Install the servos as shown, using the included 3mm hardware, two #2 tapping screws and the diagram below. For quick prototype assembly, you can use rivet fasteners (sold separately: NSRF-01) as illustrated. Make sure that the servos are centered before attaching to the "C" brackets.
| 4 x | |
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Figure 7.
Attach the leg assemblies to the 3" U-Channel as shown, using four #2 tapping screws.
| 4 x | |
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Figure 8.
Attach the 3/4" standoffs to the electronics carrier using four 4-40 x 1/4" hex socket head cap screws.
| 4 x | 4 x |
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Figure 10.
Attach the 5/16" standoffs to the U-Channel as shown, using two 2-56 x 1/4" screws.
| 2 x | 2 x |
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Figure 11.
Attach the electronics carrier as shown, using two 2-56 x 1/4" screws.
| 2 x | |
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Figure 12.
Attach the power switch to the electronics carrier as shown.
Figure 13.
Your battery can be attached with a wire tie or Velcro, not included.
A 6vdc battery will power the robot fine, however, as the battery discharges, the SSC-32 will reset even though there is still sufficient power for the servos. A 7.2vdc battery will lessen this effect, but it is slightly harder on the servos.
For maximum run time, power the VL input from a separate 9vdc battery. Remember to remove the VS=VL jumper to isolate the two supplies. The 6 or 7.2vdc battery is still required!
Figure 14.
Install the SSC-32 using four 4-40 x 1/4" screws. Make sure to orient the SSC-32 as shown.
| 4 x | |
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Figure 15.
Connect the servos to their appropriate I/O channels on the SSC-32. Consult Table 20, and make sure to check your work. Connect the wiring harness to VS1 or VS2 on the SSC-32 as shown. Note, red is (+) and black is (-). If you like, you can flip the SSC-32 around to protect the wires and take up less space.
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Table 16. |
Figure 16.