ANNIN ROBOTICS AR3 User manual

Model AR3 Robot Manual
OPEN SOURCE 6 AXIS ROBOT

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Contents:
•Electrical Safety
•Overview
•Chapter 1 –Bill of Materials
•Chapter 2 –Robot Assembly
•Chapter 3 –Enclosure Assembly
•Chapter 4 –Wiring Diagram
•Chapter 5 –Robot Gripper
•Chapter 6 –Specifications
•Chapter 7 –Startup Procedure
•Chapter 8 –Programming
•Chapter 9 –Open Loop Version (AR2)

Electrical Safety
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ELECTRIC SHOCK HAZARD. The construction of this control enclosure poses potential
exposure to alternating current and direct current which has the potential to cause injury
or death. This equipment should be constructed and serviced by trained or qualified
persons.
Keep the area around the device clear and free from dust before, during, and after
installation.
Wear safety glasses if you are working under any conditions that could be hazardous to
your eyes.
Do not perform any actions that create a potential hazard to people or make the
equipment unsafe.
Never install or manipulate wiring during electrical storms.
Never install electrical jacks in wet locations unless the jacks are specifically designed for
wet environments.
Operate the device only when it is properly grounded.
Ensure that the separate protective earthing terminal provided on this device is permanently
connected to earth.
Replace fuses only with fuses of the same type and rating.
Do not open or remove chassis covers or sheet-metal parts unless instructions are
provided in the hardware documentation for this device. Such an action could cause severe
electrical shock.
Do not push or force any objects through any opening in the chassis frame. Such an action
could result in electrical shock or fire.
Avoid spilling liquid onto the chassis or onto any device component. Such an action could
cause electrical shock or damage the device.
Avoid touching uninsulated electrical wires or terminals that have not been disconnected
from their power source. Such an action could cause electrical shock.
Always ensure that all modules, power supplies, and cover panels are fully inserted and that
the installation screws are fully tightened.

OVERVIEW
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About building this robot:
The AR3 robot is an 6 axis robot project that is free and open source. The following manual is
provide so that people can build this 6 axis robot themselves. All software, print files and
manuals are available for download on the Annin Robotics website downloads page. All the
components you need to build this robot are outlined in Chapter 1. The assembly of the robot
arm is outlined in Chapter 2. The assembly of the electrical enclosure is outlined in Chapter
3..
Components Needed to Build this Robot:
The following is an overview of the 5 component groups needed:
•3D covers and spacers (you must print these yourself) see chapter one “spacers and
covers” section.
•Structural components - You can print these yourself to build a 3D printed robot or you
can purchase an aluminum parts kit from the robot kits page to build your robot from
aluminum https://www.anninrobotics.com/robot-kits. There are 27 structural components –
see chapter one “structural components” section.
•Hardware components –this includes the bearings, belts, pulleys, sprockets, chain, shafts,
pins, machine screws and set screws. These can be purchased from multiple sources –see
chapter one “hardware components” section. If you have difficulty finding these component
or wish to buy them all in one place I buy them all in bulk and have made a hardware
components kit available on the robot kits page: https://www.anninrobotics.com/robot-kits.
•Stepper Motors and Drivers –the 6 motors, drivers and power supply are available
directly from Stepperonline, there is a link to this package on the robot kits page:
https://www.anninrobotics.com/robot-kits.
•Electrical components –You must source all of the electrical components shown in the
Electrical components section of Chapter 1. These can easily be purchased from places
such as Amazon or AliExpress. I currently don’t have an electrical components kit available
however I have had many requests and it is something I am looking into.

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General Robot Assembly notes:
•Use medium strength thread locker on all screws.
•All belts and chains should be tensioned using moderate tension (do not over tighten or
stress belts and chain).
Tools Needed:
•General hand tools including metric hex key set, locking pliers, wire cutters, wire
strippers.
•Wire ferrule crimpers and wire ferrules.
•Soldering Iron and flux core silver bearing solder.
•Heat gun or lighter for shrink tubing
•3D printer and printer filament.
•Various size drill bits for clearing holes in 3D printed components.
•M3, M4, M6 and M8 taps for threading plastic components.
•Epoxy is used for the J6 limit switch tip. Epoxy is also used in some areas of the robot
assembly when using 3D printed components.
Bearing Fit:
The CAD models for the AR2 robot are sized for a slight press fit on all bearing and race
diameters. The assembly steps in this manual also reference pressing the bearings and races
in place. Given customer feedback and the fact that most don’t have access to a quality
bearing press or hardware I have tried to make sure the aluminum kits offered are closer
to a slip fit. If bearings get improperly wedged or tilted and then attempt to press, severe
damage can occur. Given the opportunity for bearings to jam and permanently damage to
occur I have opted to try and provide kits that error on the side of a looser fit to avoid
part damage and frustration. If the tolerance stack up on your components results in a
race that is slightly loose please use a small strip of shim stock or wax paper to alleviate
any movement. A small dab of epoxy can also be used.
The bearing oil that comes on bearings should be sufficient lubrication given the low
speed and pressure of the robot joints. If additional lubrication is needed a very small
about of white lithium grease is recommended.

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3D PrintingYour Robot:
This manual shows the construction of the robot using aluminum for the main structural
components but the robot can also be constructed using all 3D printed components. The .stl
print files for all components are here: https://www.anninrobotics.com/downloads The
construction illustrated in this manual is the same using either aluminum or 3D printed
components - note the following details if using 3D printed components:
•3D printed components require all threaded holes to be cleared with appropriate drill
size and then tapped.
•All printed structural components were printed at minimum 50% infill with the exception
of the J2 and J3 drive spindles and tension rings which were printed at 90%+ solid. Parts
were printed at 2mm layer height and 5 layer thick shells.
•All printed covers and spacers were printed at 20% infill at 2mm layer height and 5 layer
thick shells.
•The robots I have 3D printed were made using ABS at 220° nozzle temperature. I have
not personally tried using other materials but I have received feedback from numerous
people who have used PLA, PET and carbon fiber reinforced filaments without issues.
•The J1 baseplate, J1 baseplate spacer and J2 arm larger than most 3D printer beds and
therefore are printed in 2 pieces and require being epoxied together.
•The J1 spindle is printed in 2 pieces and requires the center alignment plug be epoxied
into the end of the spindle –this is the center hub that centers the 60T timing pulley.
•The printed design calls for additional reinforcements to be epoxide in place around the
J1 base and at the base of the J2 arm (see details at the end of this manual)
•The J4 tube cannot be 3D printed; if building a fully 3D printed robot you will need to cut
and drill aluminum tubing as shown in structural components BOM section of chapter 1.
•2 spools of filament are needed for printing the primary structural components. A 3rd
spool is needed if you wish to print your covers and spacers in a different color.

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Electrical Enclosure:
•7th AXIS
Please note there are several steps that refer to an optional 7th axis travel track. The robot
itself only requires 6 drivers and 6 motor plugs/cables. If you would like to build your
enclosure to accommodate a 7th axis you can add a 7th driver as well as a 7th plug and cable
but it is optional.
•Enable Circuit
Please note this assembly manual does not show wiring of the enable circuit. The enable
circuit will likely not be used by most and is used to disable the motor drivers. The enable
circuit disables each of the motor drives when 5vdc is applied to the enable terminals on the
driver. Keeping safety in mind; if you have an application where the robot needs to be guarded
by a “fence” circuit or safety door you can run +5vdc to all the ENA+ terminals and then
-5vdc to safety switch, and then back from the safety switch to each of the ENA- terminals.
When the safety switch is made and -5vdc is passed through the switch to the DIN rail enable
terminal the circuit will be completed and the drives will be disabled. It is not necessary to
use the enable circuit. For simplicity in design and lowest cost I chose to wire the E-Stop
button to cut off 24vdc to the drivers. Most inexpensive E-Stop buttons are normally closed
but if desired you could alternatively use a normally open E-Stop button or relay wired to the
enable circuit rather than disrupting the 24vdc supply to the drivers.
•Arduino Mega and 8 Channel Relay Board
Note the Arduino Mega and 8 channel relay board is not necessarily needed for the operation
of the robot itself. The Arduino Mega is a good low cost board that can accept 5vdc inputs
and outputs. The relay board has been included in the design for general purpose use or to
control a pneumatic gripper solenoid (please see chapter on Robot Gripper). The 8 channel
relay board can be used to control any higher voltage device or actuator that you may need
the robot to control.
•Arduino / Teensy 3.5 mount
This manual shows mounting the control boards in a 3D printed raised mount. It also shows
soldering female PCB pin headers to the Teensy 3.5. Alternatively you can use the Teensy 3.5
with male pins and a breadboard if desired. I prefer not to use breadboards and would rather
take the time to solder the female pins in place, as of this point in time the Teensy 3.5 is not
available with female header pins.

Several steps in this
manual will call for crimping
both straight and 90°quick
disconnects for 22awg
wire.
Be sure to use a quality
crimper for straight
disconnects (shown left)
Be sure to use a quality
crimper for 90°disconnects
(shown right)
Several Steps in this
manual will call for braided
sleeve to be placed over
electrical wires. Make sure
that as soon as you cut any
braided sleeving you use a
lighter or flame to carefully
melt the ends of the sleeve
as shown.
If you do not melt the ends
the sleeve will un-braid and
not hold the wires together.
Using Braided Sleeve
Using Crimp Quick Disconnects

Please also note that
depending on supplier
some quick disconnects do
not plug onto limit switch
terminals tightly. If you find
quick disconnects slip off of
terminals too easily you
can place disconnect into a
pair of pliers as shown and
very gently close the
disconnect gap slightly.
Be very careful not to
compress connector too far
–only gently compress if
needed.
Note that I have found it
helpful to strip 10mm of
insulation off of wire and
then fold wire over on itself
before inserting into quick
disconnect.
This ensures a tight wire fit
into terminal.
After crimping always pull
on wire and make sure you
have a good crimp.

Use soldering iron and
rosin core electrical solder
to pre apply solder to the
ends of each wire.
This is also known as
“tinning” the wire end.
Several steps in this
manual will call for
soldering and heat
shrinking wire connections
together.
Strip wire ends of both
wires and twist wire
strands.
Insert length of heat shrink
tube over one of the wire
ends.
Soldering Wire Connections