AL5B Arm Assembly Instructions Rev. 1.
Updated 11/29/2010.
Safety first! Wear eye protection and never touch a powered robot!
Note: Loctite or thread locks can be used on the construction of the aluminum components. However, don’t use them with Lexan, as they are not necessary and may cause damage.
**Image of complete arm. **
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Lexan Preparation.
The lexan pieces have a protective covering that needs to be removed before assembly. When the laser cuts, the covering melts into the cut edge which can make removal difficult. If you gently scrape the cut edge with a flat blade screwdriver, the covering can easily be lifted and peeled off. On smaller pieces the coverings can be more difficult to remove. If you have trouble you can gently scrape the cut edge, then use duct tape to lift the covering off.
For further information on lexan, see this page.
Lexan Preparation.
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Step 1.
Connect the “C” bracket to the large “C” bracket as shown. Use two 2-56 x 1/4" screws and 2-56 nuts.
** 2 x**
** 2 x**
Figure 1.
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Step 2.
Install the mechanical dampening panels as shown. Use four #2 tapping screws.
Figure 2.
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Step 3.
Insert the 4-40 x .5" Phillips head screw through the hole in the multi-purpose bracket as shown. Secure with a steel nut.
** 1 x**
** 1 x**
Figure 3.
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Step 4.
Slide the large “C” bracket end of the bracket assembly over the screw as shown, and secure with a nylon insert lock nut. The amount of friction can be adjusted by tightening or loosening the lock nut. Start with the nut loose, and if the arm seems to wobble a bit, you can tighten this joint to correct the wobble. Caution - don’t over-tighten this! If the arm is operated with the mechanical dampeners too tight, the servo WILL heat up and CAN be damaged!
** 1 x**
Figure 4.
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Step 5.
Figure 5 show a typical mega-size servo with its default servo horn at center position. You will need to replace this black servo horn with the round nylon servo horn.
Remove the servo horn screw, being careful to not rotate the servo horn itself. Pull the servo horn off, then press the nylon servo horn in place, as close to the alignment shown as possible. Replace the servo horn screw.
Make sure your servo looks like the image. The arrows in the image point to the screw holes you will use.
Figure 5.
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Step 6.
Attach the HS-755HB servo to the base bracket as shown using the 3mm hardware; follow the diagram below. Use two #2 x 1/4" tapping screws to secure the bracket to the servo horn. Route the shoulder servo wires underneath the servo. Plug the servo into channel 1 on the SSC-32. Carefully rotate the base to an extreme, and use a wire tie to take up the slack in the servo cable.
** 2 x**
Figure 6.
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Step 7.
Attach two of the tubing connector hubs to the short side of the “L” brackets, using four 2-56 x .250 screws and 2-56 nuts.
** 4 x**
** 4 x**
Figure 7.
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Step 8.
Connect the hubs to the 2.25" tube using two 4-40 x .250" screws. Tighten these down tightly.
** 2 x**
Figure 8.
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Step 9.
Attach the tubing structure to two Multi-Purpose brackets as shown, using four 2-56 x .250 screws and 2-56 nuts.
** 4 x**
** 4 x**
Figure 9.
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Step 10.
Insert the 4-40 x .5" Phillips head screw through the hole in the multi-purpose bracket as shown. Secure with a steel nut.
** 1 x**
** 1 x**
Figure 10.
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Step 11.
Slide the screw on the forearm assembly through the dampening discs as shown, and secure with a nylon insert lock nut. The amount of friction can be adjusted by tightening or loosening the lock nut. Start with the nut loose, and if the arm seems to wobble a bit, you can tighten this joint to correct the wobble. Caution - don’t over-tighten this! If the arm is operated with the mechanical dampeners too tight, the servo WILL heat up and CAN be damaged!
** 1 x**
Figure 11.
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Step 12.
Figure 12 illustrates a typical standard-size servo with its output horn (the round white part) at center position. Make sure your servo looks like the image. The arrows in the image point to the screw holes you will use.
Figure 12.
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Step 13.
Attach the HS-645MG elbow servo to the bracket as shown using the 3mm hardware; follow the diagram below. Use two #2 x 1/4" tapping screws to secure the bracket to the servo horn. Route the shoulder servo wires over the servo. Plug the servo into channel 2 on the SSC-32.
** 2 x**
Figure 13.
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Step 14.
Attach the Little Gripper connector to the short “C” bracket using two 2-56 x .250" screws and 2-56 nuts.
** 2 x**
** 2 x**
Figure 14.
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Step 15.
Attach the short “C” bracket to the other Multi-purpose bracket as shown.
Figure 15-1.
Figure 15-2.
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Step 16.
Attach the HS-475HB wrist servo to the bracket as shown using the 3mm hardware; follow the diagram below. Use two #2 x 1/4" tapping screws to secure the bracket to the servo horn. Route the shoulder servo wires over the servo.
** 2 x**
Figure 16.
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Step 17.
Attach the Little Grip to the lexan as shown, using three 4-40 x .375" button head screws and acorn locking nuts. Only three screws are used (shown in the image) as the body of the gripper servo is in the way for the fourth.
Make sure the HS-422 servo is aligned to mid-position, and the gripper is halfway open. Now the servo and gripper will be aligned correctly. Remove the servo screw and horn. Slide the servo into the gripper from the bottom. You may need to wiggle it a bit to get it seated properly. Use the servo screw to attach the servo. Tighten this down, but then unscrew it half a turn. Too much friction can bind the servo.
** 3 x**
** 3 x**
Figure 17.
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Step 18.
Add a 12" servo extender cable to the gripper servo, and a 6" extender cable to the wrist servo.
Figure 18.
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Step 19.
Carefully bend the wrist servo back as far as it will go, and use wire ties to secure the servo cables as shown. Make sure to leave slack in the gripper servo cable, don’t pull it too tight.
Figure 19.
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Step 20.
Carefully stretch the arm forward as far as it will go, and use wire ties to secure the servo cables as shown. Make sure to leave slack in the cables, don’t pull them too tight. Plug the servos in according to Table 20.
Table 20.
[table=1,320,#000000][tr][td=50,#808080,#C0C0C0,center,1,1]ARC-32 I/O[/td][td=50,#808080,#C0C0C0,center,1,1]Servo[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]16[/td][td=50,#808080,#FFFFFF,center,1,1]Base[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]17[/td][td=50,#808080,#FFFFFF,center,1,1]Shoulder[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]18[/td][td=50,#808080,#FFFFFF,center,1,1]Elbow[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]19[/td][td=50,#808080,#FFFFFF,center,1,1]Wrist[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]20[/td][td=50,#808080,#FFFFFF,center,1,1]Gripper[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]21[/td][td=50,#808080,#FFFFFF,center,1,1]Wrist Rotate
(Optional)[/td][/tr][/table]
Figure 20.
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Step 21.
Plug the PS2 cable into the ARC-32 AUX1 and AUX2 header as shown in figure 21.
Figure 21.
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Step 22.
If you would like to use springs for load-balancing, replace the servo attachment hardware in the locations shown, following the diagrams below. Hook the springs together after they’re secured.
http://www.lynxmotion.com/images/inv/spr03.gif
http://www.lynxmotion.com/images/inv/spr02.gif
Figure 22.
http://www.lynxmotion.com/images/assembly/al5b/al5b11.jpg
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Step 23.
Download and install BasicMicro Studio then
download AL5 Arm for ARC-32/PS2 basic file. Open the basic file in BasicMicro Studio. Select BasicAtomPro and the ARC-32 comport in the Studio dropdown boxes. Click Program.
Once the programing has finished hit the Select button on your PS2 controller to enter Setup mode. The arm should move to the position shown in figure 23.
Figure 23.
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Step 24.
The first step in calibration is to move the arm to the position shown in Figure 24. The commands available during calibration are listed in Table 24.
Table 24.
[table=1,320,#000000][tr][td=50,#808080,#C0C0C0,center,1,1]PS2 Buttons[/td][td=50,#808080,#C0C0C0,center,1,1]Function[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Left/Right D-Pad[/td][td=50,#808080,#FFFFFF,center,1,1]Moves active servo[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Hold L2[/td][td=50,#808080,#FFFFFF,center,1,1]Activate Shoulder[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Hold L1[/td][td=50,#808080,#FFFFFF,center,1,1]Activate Elbow[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Hold R2[/td][td=50,#808080,#FFFFFF,center,1,1]Activate Wrist[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Hold R1[/td][td=50,#808080,#FFFFFF,center,1,1]Activate Base[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Square[/td][td=50,#808080,#FFFFFF,center,1,1]Save Position 1[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Circle[/td][td=50,#808080,#FFFFFF,center,1,1]Calculate Calibration and exit Setup[/td][/tr][/table]
Figure 24.
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Step 25.
Now press the Square button on the PS2 to save Position 1 and move the arm back to its starting position. Now use the same controls to move the arm to the position shown in Figure 25.
Figure 25.
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Step 26.
Press the Circle button to finish calibrating the arm and exit from Setup. The arm will move to the position shown in Figure 26. if calibration was done correctly.
Figure 26.
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Step 27.
The arm assembly is now complete. Table 27. lists the PS2 controller functions available.
Table 27.
[table=1,320,#000000][tr][td=50,#808080,#C0C0C0,center,1,1]PS2 Buttons[/td][td=50,#808080,#C0C0C0,center,1,1]Function[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Select[/td][td=50,#808080,#FFFFFF,center,1,1]Setup mode(See Table 22.)[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Left Joystick[/td][td=50,#808080,#FFFFFF,center,1,1]Gripper X/Y position[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Right Joystick[/td][td=50,#808080,#FFFFFF,center,1,1]Gripper Z position and Angle[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]L1/R1[/td][td=50,#808080,#FFFFFF,center,1,1]Gripper Open/Close
(Pressure Sensitive)[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]L2/R2[/td][td=50,#808080,#FFFFFF,center,1,1]Wrist Rotate
(Pressure Sensitive)[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]Triangle[/td][td=50,#808080,#FFFFFF,center,1,1]Move to Start position[/td][/tr][tr][td=50,#808080,#FFFFFF,center,1,1]X[/td][td=50,#808080,#FFFFFF,center,1,1]Power Down Servos
(only works with analog servos)[/td][/tr][/table]
Warning: The arm is robust mechanically, but the servos can be damaged by improper use. An example would be if the arm was told to move to an unobtainable position, like the surface the arm is mounted to, or by crashing the arm into itself, or other objects. The elbow servo is the most vulnerable because it holds the entire weight of the forearm. Load balancing springs should be added to reduce some of this load.
Warning: People do not like holding heavy objects with their arms outstretched in front of them. Servo based robot arms don’t like it much either. Remember, the most important rule for servo based robot arms: Park the arm when not in motion! When it’s moving or at rest it’s usually ok. When it’s holding an object it should do so for the minimum amount of time required to do the job. You can always touch the servo case to see if it’s getting hot.