Biped BRAT Jr. Assembly Guide

Last modified by Eric Nantel on 2024/07/03 09:21

Biped BRAT Jr. Assembly Guide. Updated 08/06/2009.

Hardware:
- 1 x Alum. Channel - 3" Single Pack (ASB-503)
- 2 x Multi-Purpose Servo Bracket Two Pack (ASB-04)
- 1 x "L" Connector Bracket Two Pack (ASB-06)
- 1 x "C" Servo Bracket w/ Ball Bearings Two Pack (ASB-09)
- 1 x Robot Feet Pair (ARF-01)
- 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.

Step 1.
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

Figure 1.

Step 2.
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

Figure 2.

Step 3.
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

Figure 3.

Step 4.
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.

Step 5.
Your two leg assemblies should look like the image so far.

Figure 5.

Step 7.
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.

4 x

Figure 7.

Step 8.
Attach the leg assemblies to the 3" U-Channel as shown, using four #2 tapping screws.

4 x

Figure 8.

Step 10.
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

Figure 10.

Step 11.
Attach the 5/16" standoffs to the U-Channel as shown, using two 2-56 x 1/4" screws.

2 x	2 x

Figure 11.

Step 12.
Attach the electronics carrier as shown, using two 2-56 x 1/4" screws.

2 x

Figure 12.

Step 13.
Attach the power switch to the electronics carrier as shown.

Figure 13.

Step 14.
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.

Step 15.
Install the SSC-32 using four 4-40 x 1/4" screws. Make sure to orient the SSC-32 as shown.

4 x

Figure 15.

Step 16.
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.

SSC-32 I/O	Servo
00	Right Ankle
01	Right Hip
16	Left Ankle
17	Left Hip

Table 16.

Figure 16.

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Created by Eric Nantel on 2024/07/03 09:21