angellm/thor

DIY 3D Printable Robotic Arm

Thor is an Open Source and printable robot arm with six degrees of freedom. Its configuration (yaw-roll-roll-yaw-roll-yaw) is the same used by most of the manipulator robots on the market. In its extended position, Thor is about 625mm high and can lift loads up to 750 grams.

The project started in 2015 as a final degree project called “Design and implementation of an Open Source, 3D printed 6DOF robotic arm”. Since then, this project has continued to develop little by little.

The main purpose of this project was to design a robot that could be used in universities and schools to teach robotics.With this in mind, the design had to be affordable and accessible. Releasing the source files and doing so under an open source licence was the best option: anyone could study any element of the robot in depth and, moreover, modify or adapt it to their needs.

The cost of the whole materials is under 350€. Being so affordable, I think almost every school/university/maker could make good use of at least one!

In terms of licenses, I wanted this project to be Open Source because I want anyone to have the opportunity to study, modify and improve it.

Thor has been developed using only open source tools: FreeCAD for the 3D modeling, KiCAD for the PCB design and GBRL as firmware for the control electronics. In this way, access to knowledge can be guaranteed to anyone, anywhere, without any economic cost. There is not a single reason for not hacking Thor!

If you want to know more about this project, visit the Thor Website, where you will find documentation, manuals and a forum to solve all your doubts.

Repository Index

• doc - Misc documentation files
• freecad-src - FreeCAD source files of every piece of Thor
• step - step files of every piece of Thor
• stl - stl files of every piece of Thor
• wiki - currently deprecated, for updated info visit the project's website
  • FAQ - Frequently Asked Questions
  • Component list & Where to buy - List of every component needed in this project and links to online shops where they can be bought.
  • ThorBuilders - List of Thor builders

License

All files included in this repository are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License

thor's Issues

Articulations bodies

Hi, i'm printing all the parts and I only have left the Art1Body, Art3Body but each will take +24h to print because they need supports. I live with more people and can't print at nights.

Could you please tell me what settings did you use?
Or could you modify them to print them in several parts?
Thank you.

Art 4 Transmission Column unnecessarily tight fit for bearing

The smallest extra print material will mean the bearing does not fit down the central shaft and can be damaged by inexperienced makers trying to force it. Instead of a single inner radius that is the exact radius of the bearing, there could be a loose fit for almost all the shaft except the final place where the bearing would continue to fit snugly. As there is a screw holding the bearing in, there is no danger of the bearing falling out.

Servo Motor - PORTG0 (pin41) no PWM output

Hi,

Built the board, loaded the firmware on. All commands work except M3 to control the servo. Probed digital pin 41 no PWM output, is there something I'm missing? Please help

Feedback sensors

Currently the control of the arm is based on a open kinetic chain. The Zero (Home) position is set at the start and the subsequent movements are based on that reference.
The inclusion of encoders or potentiometers as angle sensors could allow a closed kinetic chain control and new features like recording movements manually.

Modificar Asgard

Buenas de nuevo!!!
Después de mucho tiempo, he retomado el proyecto... y he pensado usar una raspberry pi con pantalla táctil para controlar a thor, pero al instalar asgard en la raspberry, resulta que no cabe en la pantalla, que tiene una resolución máxima de 800x400..
Hay alguna manera sencilla de modificar el gui.py para poner solo lo básico?
El botón de conectar, y los sliders de las articulaciones, y de paso, eliminar el boton “go” y que envie el gcode directamente al mover el slider...
gracias!!!!

Duda en el montaje / Doubt in the assembly

hola de nuevo...
he empezado el montaje de thor, y tengo una duda...
las siguientes piezas forman parte del mismo montaje?
Art3TensionerBody.stl
Art3TensionerPulley.stl
2 × MF84ZZ Bearing
2 × 14mm x ∅5mm Rod

el paso del rodamiento es de 4mm, y la varilla es de 5mm, por lo que no encaja.

Hello again...
I have started the assembly of thor, and I have a doubt ...
the following parts are part of the same assembly?
Art3TensionerBody.stl
Art3TensionerPulley.stl
2 × MF84ZZ Bearing
2 × 14mm x ∅5mm Rod

the bearing pitch is 4mm, and the rod is 5mm, so it does not fit.

Alimentación del servo de la articulación 6

En primer lugar me disculpo por escribir en castellano ( Traducción después con google)...

Estoy montando la electrónica "ControlPCB" siguiendo el esquema, y me he fijado en que el servo va conectado directamente sin ningún regulador de tensión... por lo que imagino que lo estamos alimentando con los 5v de la placa Arduino Mega, es correcto??

Gracias.
Gran trabajo,

estoy esperando a que me lleguen todas las piezas mientras imprimo todo...

Traducción :

First of all I apologize for writing in Spanish (Translation later with google) ...

I am mounting the electronics "ControlPCB" following the scheme, and I noticed that the servo is connected directly without any voltage regulator ... so I guess we are feeding it with the 5v of the Arduino Mega board, is it correct? ?

Thank you.
Great job,

I'm waiting for all the pieces to arrive while I print everything ...

Confusion on PCB circuit

Hi! We are planning to build Thor but had some confusion regarding the PCB circuit. We were confused on what P1...P8 were on the circuit diagram and how they are connected in the circuits. Thank you so much!

Smoothie

Cool project !

How about using a Smoothieboard and the Smoothie firmware instead of a grbl-based solution ?
We make it very simple to add new "arm solutions" to convert cartesian coordinates into actuator coordinates ( https://github.com/Smoothieware/Smoothieware/tree/edge/src/modules/robot/arm_solutions )
Also, it's 32bits, so it'll be faster and smoother. And it's got a larger community, is very actively developed, etc ...
We'd send you a free board if you say you'll add the code to smoothie.

Cheers :)

Suggested Material for Printing

Could not find (e.g. FAQ) which material is suggest, respective which limitations are implied. (PET - flexible, PLA - low temp. etc.)

Which experience exist?

Hello

I can not download all the documents, can you help me?

Cn

Awesome

Some dimensions that may be wrong

Hello everyone,

I am printing a complete set of Thor's printed parts and while testing the fit of the different parts with bearings, bolts, etc I have noticed some dimensions that make assembly very hard or require the printed part to be postprocessed (sanded, drilled, etc.).

This notes refer to the DesignUpdate branch, which is the one that I am using.

These are the ones that I have caught by now:

• Gripper: every bolt head pocket have a radius of 2.7mm. M3 DIN912 bolts have a 2.75 nominal radius, so the heads won't fit. Other bolt head pockets in Thor have 2.95mm radius. Changing the Master bolt head won't be enough since not every head references to the entity, it has to be done one hole at a time.
• BaseBoxBody
  • fan bolt head pocket have a radius of 2.7mm. Changing the Master bolt head won't be enough since not every head references to the entity, it has to be done one hole at a time.
  • insert holes are too big for 5mm inserts. Holes should be at least a couple of tenths smaller to hold the insert.
• Art56GearPlate inner bore for a 625 bearing is only 16mm in diameter, some slack has to be included to be able to push the bearing in.
• I find BearingFix parts hard to get into their pockets, I would reduce the diameter by some tenths.
• BearingPlug won't fit in it's hole. Maybe is meant to be printed in flexible material?

Other stuff:

• This is a FCSTD1 file that has made his way into the repo: https://github.com/AngelLM/Thor/blob/DesignUpdate/freecad-src/Art2SideCover.FCStd1

Sorry not to be able to change it myself, my set of files is already very different from the source files and my git knowledge is not very extensive.

I'll post here if I spot more things like these.

Diego.

Control PCB update

I made the Control PCB as a prototype and it worked well. It's necessary to update it in order to add some features and by the way design it to produce it professionally instead of making it with a CNC.

Where does the logic lie?

Hi @AngelLM

First of all, thank you very much for creating Thor, very impressive and helpful indeed.
I have been looking for some control logic (or maybe inverse kinematics solver, etc.) and hardware drivers, but I can't seem to find any actual code in this repository, there are tons of nice assets (CAD files) but the actual programs are no where to be found.

Where do you keep your logic? Maybe this is how a robotic project is typically organized, but as a software developer making his first foray into this field, I am confused by it.

The hardware design side of things is tremendously interesting, but can you write more about the software aspects of the project?

Thank you very much.

BR,
Roy

Arduino Code to Control Stepper Motor

Hello,

Instead of using a PCB, I am building the firmware configuration on a breadboard. I am having trouble controlling the motors with GRBL. In the grbl file, is there a place that defines what each Arduino pin does?

Thank you!

Endstop on PS1

PS1 in the diagram connects to an infrared sensor as an endstop. How does it work? I am kind of confused because I think we need to know the min and max positions on both ends of the opto disk. I see there is a gap in the opto disk, I am not sure, do we use the gap for min/max detection and homing?

Cooper plate?

In bill of materials

Art1 Body STEP file has faulty topology

The top curved area of the art 1 body part has faulty topology.

Document Improvement in STL files

Thanks for this great work, but I don't understand what's the naming convention, like Art1Body and Art3Body?
Could you add two lines of comments into the README in the STL folder?

Parts inside Art56 casing hard to access

I like how everything is a tight fit - it uses the space well. However, I think making it a two-piece clamshell (splits along a "U" down the axis) would make it much easier to access.

Art56 Small Gears do not fit all variations of GT2x40 pulleys

It's a clever use of a set screw to attach the pulley to the 3d printed gear! However, it looks like the GT2 standard doesn't apply to the set screws. The pulleys I ordered ended up having 4mm (not 3mm) set screw holes that do not line up with the hole in the gear.

So I used hot glue. I'll see if it can handle the torque.

cinematic motion algorithm

hi, sorry to open ticket for my question , but actually I'm little lost to find the methods can convert input location (Cartesian , polar) to the optimized cinematic motions of each axis? for example how to defined the best path from A to B coordinates and how it converted the cinematic motion for each axis? what is the optimization function & type ?how to define cinematic motion parameters of specific arms? I really appreciated for your hint

License confusion

The readme says the files in this repo are licenses by a CC-BA-SA (Creative Commons Attribution-ShareAlike 4.0 International License). However, the license file says it is GPL2. So... Which is the latest version licensed under?

Readme: Printer Requirements

Could you mention in the readme which kind of printer was used to print Thor, please?
Is 200x200x180 enough space to print all parts?

Payloads

Hi! Does the project support laser engraving or 3d printer heads connection? I found only cnc mill head connection sample.

Servo not move... / El servo no se mueve

hola de nuevo, ya tengo varias articulaciones montadas, y he empezado a probar la electronica, pero tengo un par de problemas... todos los motores se mueven, aunque no todos en los grados que deberian ( he usado tu configuracion de GRBL ) , será cuestion de modificar los pasos/mm , pero la pega es, que usando Asgard, la pinza, no rota, el boton de la articulacion 5 y de la 6 hacen lo mismo, y por ultimo el servo no hace nada...
he probado con otro por si a caso y tampoco funciona, pero si hace un pequeño movimiento al iniciar el sistema.

Gracias!

hello again, I already have several assembled joints, and I have started to test the electronics, but I have a couple of problems ... all the motors move, although not all in the degrees that they should (I have used your GRBL configuration), it will be a matter of modifying the steps / mm, but the glue is, that using Asgard, the clamp, does not rotate, the button of the articulation 5 and the 6 do the same, and finally the servo does nothing ...
I've tried another one just in case and it doesn't work, but it does make a small movement when starting the

Thanks

bevel gears - how?

Please: How did you design your beveled gears?

Looking for a Print Inventory List, and unit scaling on STLfiles.

Hi, could you please let me know where I can find a Bill Of Materials that includes the quantity of each number of 3D printed component that need to be printed. Additionally can you please let me know if the .stl files are scales in in, mm, or cm.

-Thanks

Inverse Kinematics implementation

It could be nice to have the IK implemented, in order to control the robot using XYZ coordinates and a rotation matrix.

Website down

http://thor.angel-lm.com/ seems to be down

Can I use two Uno CNC shields instead of building the Thor-specific PCB?

I did not try yet but I think this is possible, right? if so it saves a whole lot of time to mill the PCB with a CNC

Notes/feedback about FreeCAD used within collaborative projects like Thor

It would be helpful to understand what are some of the workflows that this collaborative project is encountering while using FreeCAD. Anything from positives, negatives/bugs, and feature requests (that would make collaboration more optimized) etc...

Please notate this ticket. Eventually these notes can be reported back to the FreeCAD community.

Stepper Motor Gearbox/Planet drive

I cant seem to find that gear ratio/model number for the #2 articulation, help?!

Fix broken URLs in README.md#repository-index section

Several broken links exist in https://github.com/AngelLM/Thor/blob/developer/README.md#repository-index

5mm (diameter) rods do not fit on 625ZZ bearings and similar issue with motor shaft and pulley

In the process of building Thor I've run into the issue that the 5mm (diameter) rods do not fit in the 625ZZ bearings that were on the bill of material... Similarly, the GT2-6 Timing Belt Pulley 20T (inner bore of 5mm) does not fit at all on the shaft of the Stepper Motor 17HS13-0404S-PG5 also provided in the bill of material.

Would it be possible to know what you used instead of these components to ensure a proper fit? Thanks!

Malfunction due to steppers overheat

Steppers overheat causing printed gears deformation and malfunction of the arm.
Possible causes:

1. Wrong stepper drivers or wrong configuration.
2. Not enough refrigeration. Actual design does not allow air flow.
   Possible solutions:
3. Find other driver that works better.
4. Modify the actual design to allow steppers refrigeration.
5. Use a more heat-resistant material to print the gears: ABS, Nylon, HIPS, PET...

ART2 BodyA that meshes with two gears always slipping. Bad fit?

Hi Angel,

After some serious testing and trials in getting the robot arm to move, it worked for a little while then I started having serious slipping issues. I watched and saw the ART2 A arm flex too much at the bottom where the only support it has are the two pins on the top motor and the ART2 Union. Not sure how everyone else has got on with this or if they have also had issue too. Would love to know. I will look to try and solve my particular issue,

Thanks in advance

Martin Barr

Tool pins connector slip off.

Pins, actually located on Art4Body piece, are glued to the printed piece. Due to use, glue stopped holding the pins and now it's impossible to connect the tool wires.
Possible solution: Design a small PCB that integrates the tool pins and the endstop as they are in the same side of the piece.

Current software to use

Hi, I have an Ultratronics Pro board but I don't know what firmware to use. Is there any firmware available for this board?

If there isn't, what board can I use to easily wire and control the arm besides the custom PCB?