I'll check that out. Im still using Solid works at the moment mostly because that's what most of the universities are using and have asked for. I do include the step files with the models so hopefully that helps some but I agree SW is a bit spendy.

I'm not sure where you're at with inexpensive CAD programs, but I really enjoy using OnShape. It has a free and paid version. The major difference between the two is privacy. If you opt for the free version, your designs can be seen by anyone with an OnShape account if they search for it. Paid subscription is costly, but then allows for your designs to be private.

I hope planned AR4 design will also be open-sourced. If so, and if community should be involved in design, is it possible to kind of use less pricey 3d modeling options? I've had a look and it looks like so far preferred solid works is in the price range of $4k which may be basically a price range of arm itself and is basically 1/2-1/3 or so of chinese-based arms (ufactory[1 xarm]).

Anybody got experience with open-source or more cheap 3d modeling software? What about FreeCAD[2] if I may ask directly?

Thanks,

Karel

[1]: https://www.ufactory.cc/

[2]: https://www.freecadweb.org/

2. remove too much wiring, use CAN bus (or etc) to reduce wire into minimal (come with encoder)

I've done some research on this topic as I kind of find CAN usage elegant in this case and found surprising fact that whole industry is kind of putting some tax on CAN based solutions. I simply cannot grasp why can based drivers are so expensive in comparison with not-integrated solutions.

Using DC/servo motors with gearboxes and CAN is completely out of the price range. Speaking about My Actuator[6] and CubeMars[7] actuators here.

Using Nema motors with 3rd party CAN driver/controller is just a bit cheaper, but still expensive. CAN driver/controller itself is in $100-200 range[3]. The most cheap here is something called AnanasStepper which started on KickStarter and you can see price development on [1][2]. E.g. from $19 to $50-70. Still even for this price the cheapest I've been able to find.

Anyway, the question is if there is no any other open-source CAN/driver/controller project available, like in the past was Mechaduino project (just controller/driver but no CAN)[4]. Looks like academia is still searching for cheap controllers/drivers as they are still thesis done on the topic, like this one from Czech Republic's VUT[5].

Have I missed anything on my research on the topic?

Thanks,

Karel

[1]: https://www.kickstarter.com/projects/249504031/ananasstepper-30-a-servo-stepper-for-multi-axis-control?ref=discovery&term=ananas%20stepper

[2]: https://www.ananasstepper.com/store

[3]: http://www.stepping-motor.cn/uim242.html

[4]: https://tropical-labs.com/shop/mechaduino-0-2-pcb/

[5]: https://www.vut.cz/www_base/zav_prace_soubor_verejne.php?file_id=223888

[6]: https://www.myactuator.com/dowload

[7]: https://store.cubemars.com/

You are not talking to yourself. Its great to hear everyone's ideas and see all the creativity that goes into these projects.

I'm might be talking to myself here... but thinking about taking the j0 plate and printed base and replacing it with a mobile battery powered aluminum chasis with mechanum wheels. The control box would be incorporated into the chasis and the internal mains power supply would go away. j0 could also be direct drive. The base would likely need an optical floor tracking sensor but otherwise only has the minimal electronics to power the wheels. Overall cost could be less than current robot with a 7th axis.

These are the things I want to look at after finishing my build. I'm doing few hours evey day now...

- test encoders on joints vs on the motor

- 48v behavior on j1-j5

- increase length of arms. j2 arm and j6 bearing arm. will likely create a new arm assembly I can switch back and forth with the original. nothing fancy. just open the cad model and increase the length + do some mass reduction cutouts.

- try out larger nema23 stepper motors on j2 and j3.

I know big changes are coming on software side so I'll wait and see for those.

I'm wanting a welding type robot so payload can be small.

size depands on total weight of robot and reduction rate we gonna choose. im in turkey so price would be nearly free for you guys :D

Im all for it ! the only "backlash" we could encounter from the community ( pardon my humor ) is that i think that one of the main goals was to make the robot accesible with parts that could be sourced easily from anywhere.

Though all ideas to make the AR4 better and more precise are always welcome.

How cheap and small could you make these wonderfull reducers ?

Sorry for taking so long promise to be more active from now on soldering is not my forte.

Happy Automating !

i just signed up, but i have been following Chris for a long time now. i learned a lot here and want to return the favor. i have my company and my goal is to build industrial quality Cycloid reducers,which is used for industrial robotic arms.and i can produce smaller and cheaper versions of them for AR4 if needed.

i still havent finished building it but i totally agree with the can bus and wiring

and obviously ROS support to do fancy stuff with it.

ill take a look at the repo but i still need to do more work on the control box.

love the bot btw

thnx chris !

Thank you all for the comments and I agree with each of your suggestions. I am actively working on some cool software updates and working with RoboDK to build a post processor and driver as well as many of the suggestions you have made.

@Kstan Simit Thank you for your enthusiasm for an ar4 and your efforts to involve the community in developing requirements of what an ar4 would focus on improving!

Personally, I agree with each of your proposed enhancements. It's a great list! I would like to add:

1. Haptic feedback: in general, I'm talking about a process when robot arm collides with a person / object, it can 'feel' it and stop.

2. Limit switches always active.

3. Look at placing J2 and/or J3 motor in a manner that acts as a counter-weight. Like what https://www.hdrobotic.com have done.

4. Graceful fail: a pre-emergency-stop solution that stops the robot cold and holds it in-situ to avoid it flopping down and breaking itself.

The ar3 is amazing as it is - completely an incredible job @Chris Annin has done here! But things can always be made better, and now that he has built a fantastic community we can source their experiences and expertise and design THE BEST "democratic robot".

sorry there is quite sometimes i no continue this topic. i still keen to make new robot arm with new design. currently im writing python web app for ar3 first and once it stable we can use for ar4. if you guys have initiative you guys may help do some homework and we combine here?

I got my AR3 up and running and have made a few upgrades, but I'd like to get them dialed in before sharing. So yes, still very interested...

I started a public git repo here: https://github.com/infinity2o/AR4/blob/main/README.md

I'm planning on building the AR3 as soon as I figure out how to order just AR3 parts.

Did anything ever come of this? I am defiantly interested in the idea, especially the part of making the wiring less complex.

i'd make solved the linear kinematics calculation and seems match with provided excel format. For circular movement may not so important at the moment. I will create 1 repository afterward since chris may not feel interested to create it.

I just started building my AR3 last week and have a ton of experience in Solidworks. I hope to have it running by the end of next week. I'm game to contribute where I can...

Hi Chris,

I suggest we create a new AR4 repository first and put some wish list and draft inside. It is better put under your github, if you feel interested can you create and invite us as member? If no next week I create new one and invite u guys.