AL5D Arm Assembly Instructions Rev. 2.1
AL5D Arm Assembly Instructions Rev. 2.1
Updated December 2014
Safety first! Wear eye protection and never touch a powered robot!
This guide shows how to assemble the AL5D arm with either the SSC-32 or the SSC-32U servo controller. Calibration can be done using: SSC-32 Servo Sequencer Utility · RIOS (purchased separately or as part of a kit) · Lynxterm (legacy software)
Note: Loctite / thread lock can be used on aluminum components, though not necessary if nuts are properly tightened. Do not use on Lexan or plastic.
Complete arm (SSC-32 shown).
The Lexan pieces have a protective covering that must be removed before assembly. The laser cut melts the covering into the cut edge. Gently scrape the cut edge with a flat blade screwdriver to lift and peel off. On smaller pieces, use duct tape after scraping. For further information see this page.
Lexan Preparation.
Connect the large "C" bracket and the 805 "C" bracket together as shown. The 805 bracket is identified by its larger size and circular extrusion. Use two 2-56 x 1/4" screws and 2-56 nuts.
Figure 1.
Install the mechanical dampening panels as shown using four 2-56 x 1/4" machine screws. Add the discs to the correct side and ensure the Lexan protective covering has been removed. Press down when screwing to ensure no gap between Lexan and aluminum.
Figure 2.
Insert the 4-40 x .5" Phillips head screw through the hole in the multi-purpose bracket as shown. Secure with a steel nut.
Figure 3.
Slide the large "C" bracket end over the screw and secure with a nylon insert lock nut. Start loose — tighten only if the arm wobbles. Caution: do not over-tighten! If dampeners are too tight the servo WILL heat up and CAN be damaged!
Figure 4.
Attach the HS-805BB servo to the base bracket using the 3mm hardware per the diagram below. Use two #4 x 3/8" tapping screws to secure the bracket to the servo horn. Route wires underneath the servo. Plug into channel 1 on the SSC-32. Rotate to an extreme and use a wire tie to take up cable slack.
Figure 5.
Attach two tubing connector hubs to the short side of the "L" brackets using four 2-56 x .250 screws and 2-56 nuts (two each). Orientation is important — the hole in the tube should be as shown so the tube lines up as in Figure 7.
Figure 6.
Connect the hubs to the 4.50" tube using two 4-40 x .250" screws. Tighten firmly.
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Figure 7.
Attach one end of the tubing structure to a Standard Multi-Purpose bracket and the other end to a Large Multi-Purpose bracket as shown, using four 2-56 x .250 screws and 2-56 nuts (two each).
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Figure 8.
Insert the 4-40 x .5" Phillips head screw through the hole in the large multi-purpose bracket in the location shown. Secure with a steel nut.
Figure 9.
Slide the screw through the dampening discs and secure with a nylon insert lock nut. Start loose — tighten only if the arm wobbles. Caution: do not over-tighten! If dampeners are too tight the servo WILL heat up and CAN be damaged!
Figure 10.
Replace the black servo horn on the HS-755HB mega servo with the round nylon servo horn. Remove the screw without rotating the horn, pull it off, press the nylon horn in place as shown, and replace the screw. The arrows point to the screw holes you will use.
Figure 11.
Attach the HS-755HB elbow servo to the bracket using the 3mm hardware per the diagram below. Use two #2 x 1/4" tapping screws to secure the bracket to the servo horn. Route wires over the servo. Plug into channel 2 on the SSC-32.
Figure 12.
Attach the Little Gripper connector to the short "C" bracket using two 2-56 x .250" screws and 2-56 nuts.
Figure 13.
Attach the short "C" bracket to the other Multi-Purpose bracket as shown. Refer to the diagram below for detailed ball bearing installation.
Figure 14.
Verify that your standard-size servo output horn is at center position as shown. The arrows point to the screw holes you will use.
Figure 15.
Attach the HS-645MG wrist servo to the bracket using the 3mm hardware per the diagram below. Use two #2 x 1/4" tapping screws to secure the bracket to the servo horn. Route wires over the servo.
Figure 16.
Add a 6" servo extender cable to the elbow servo. Plug into channel 2 on the SSC-32. Ensure colors remain the same on both sides (yellow to yellow, red to red, black to black).
Figure 17.
Step 18: Attach the Little Grip to the Lexan using three 4-40 x .375" button head screws and acorn locking nuts (three only — the gripper servo body blocks the fourth). Align the HS-422 servo to mid-position with the gripper halfway open. Remove the servo screw and horn, slide the servo in from the bottom, reseat, and replace the screw. Tighten then unscrew half a turn — too much friction can bind the servo.
Step 19: Add a 12" + 6" extender (18" total) to the gripper servo, and a 12" extender to the wrist servo. Ensure colors match on both sides of all connections.
Figure 18.
Figure 19.
Carefully bend the wrist servo back as far as it will go and use wire ties to secure the cables as shown. Leave slack in the gripper cable — do not pull too tight.
Figure 20.
Carefully stretch the arm forward as far as it will go and use wire ties to secure all cables. Leave slack — do not pull too tight. Plug the servos into the SSC-32 per Table 21. Ensure colors match on both sides of all connections.
Figure 21 (SSC-32 shown).
SSC-32 / 32U Servo Channel Assignments (Table 21)
| Pin | Servo Location | Servo |
|---|---|---|
| 00 | Base | HS-485HB |
| 01 | Shoulder | HS-805BB |
| 02 | Elbow | HS-755HB |
| 03 | Wrist | HS-645MG |
| 04 | Gripper | HS-422 / HS-425 / HS-322 |
| 05 | Wrist Rotate (optional) | Not included in kit |
SSC-32 (Serial) — Step 22a
Download and install LynxTerm. Connect the SSC-32 to the serial port and apply power. The green LED should light up. Run LynxTerm. Consult the serial troubleshooting guide if needed. Select channels 0–4 one at a time and test each carefully.
SSC-32U (USB) — Step 22b
Download and install the SSC-32 Servo Sequencer Utility. Connect USB and power the board. Set baud rate to 9600. The software auto-detects the COM port with FTDI drivers. Ensure servos 0–4 are checked, then use sliders to test each servo. See the SSC-32 Servo Sequencer manual for more information.
Figure 22a (LynxTerm).
Figure 22b (SSC-32 Utility).
SSC-32 (Serial) — Step 23a
Click "All = 1500" in LynxTerm. The arm should look like Figure 23. If any joint is off by more than 15°, check your assembly. If you did not purchase RIOS, proceed to Step 28.
SSC-32U (USB) — Step 23b
Click "Calibrate" in the SSC-32 Servo Sequencer Utility. Knobs appear next to each servo — click and drag up/down to fine-tune until the arm matches Figure 23. Once aligned, click "Calibrate" again to store offsets. If you did not purchase RIOS, proceed to Step 28.
Figure 23a (LynxTerm — All=1500).
Figure 23 (target position).
Figure 23b (SSC-32 Utility calibrate).
Remove the servo horn screw from the elbow servo. Pull the horn off, lift the arm two clicks (30°) at the elbow, and reattach the horn and screw. Note: the Hitec spline has 24 grooves — each groove is 15°.
Figure 24.
Install RIOS following the on-screen prompts. The serial number is on the back of the CD sleeve. Use the RIOS Help File (Steps 1–7). Perform an accurate calibration — if the on-screen virtual arm doesn't match the real arm, calibration is inaccurate. Study the RIOS manual to learn how to store and playback sequences.
Figure 25 (RIOS).
To calibrate the arm's Shoulder servo, click the "SSC-32" button in RIOS.
Figure 26 (RIOS).
Select Shoulder servo #2. Move the slider up (forward) until it looks like Figure 27-2. Set Min Deg to -45° and right-click to set as Min Position.
Move the slider down (backward) until it looks like Figure 27-3. Set Max Deg to 45° and right-click to set as Max Position.
Read the RIOS users guide (Help icon on main screen or C:\Program Files\RIOS_SSC-32\Help.pdf) for full usage instructions.
Figure 27-1 (RIOS).
Figure 27-2 (Shoulder at -45°).
Figure 27-3 (Shoulder at 45°).
To connect springs for load-balancing, replace the servo attachment hardware in the locations shown per the diagrams below. Hook the springs together after they're secured.
Figure 28.
The arm assembly is complete. The arm is mechanically robust but servos can be damaged by improper use — commanding an unobtainable position, crashing into itself or other objects. The elbow servo is most vulnerable as it bears the full forearm weight. Load-balancing springs reduce this load.
If you purchased FlowBotics Studio, FlowStone, or FlowArm, proceed with the instruction guides associated with those programs.
Important: People do not like holding heavy objects with their arms outstretched. Servo-based robot arms don't either. The most important rule: Park the arm when not in motion! When moving or at rest it is usually fine. When holding an object, do so for the minimum time required. You can always touch the servo case to check if it is getting hot.