Virk I – Open Hardware Scara robot
This is a Virk I, a project I’ve been working for a long time. It’s A small, slim 3-axis scara wooden desktop robotic arm. It was meant to be a learning tool or hi-tech toy. The design will be open sourced once the first phase be accomplished and all the units on the first lot be sold. The aim is to provide a small, portable, quality and beautiful robotic arm alternative, either for the academic or applied hobbyist.
Current version it’s made of Australian Blackwood (Acacia melanoxylon), acetal, pvc and standard components. Most parts where machined on a cnc mill/router/lathe.
On the shoulder and elbow it has custom design, modular hollow axis rotary joint containing three bearings inside. Two thrust bearings give the joint very low play, allowing soft, low play movements. Being hollow means that you can route the wires inside the robot most of the time, so you don’t end with a mess of wires outside, and get a more cleaner look. On the z axis it has standard 8mm linear bearing rails.
Rotary joints are driven by a nema 17 stepper coupled to custom made 3mm pulleys. Z axis is driven by a nema 11 stepper linked to a 8mm pitch leadscrew. There’s currently no gripper on the end of the arm; gripper design and built will be tackled once the first lot of eight robots be finished.
Currently, it’s driven by RAMPS 1.4 electronics. As far as I know
there’s no open source 3D printer firmware able to drive a scara robot, and it’s outside the scope of this project to make such a development, so final owners will have a challenge making this thing work. Of course you can use something like grbl to test the robot movements, but to be useful you need a firmware containing scara kinematic support. Maybe this marlin based parallel scara source could be a starting point.
I’m currently starting to test the first working unit and solving some final design issues, so the very first units to be sold will be available, very likely, at then end of this month (September).
You can find more info here.
Update: It has been pointed out here and at hackaday that there are several platforms already supporting scara kinematics:
- Smoothieware: Morgan-scara: not single arm scara, but close.
- Machinekit: According to the documentation, it has scara (single arm scara) support.
- Reprap-helios: That seems to be a similar arm, so I guess the same firmware could drive Virk I (I haven’t checked current status of this project).
- Marlin for single arm scara: This seems to be a suitable option. I will test this at some point.
I would love to hear about someone experiences using those platforms to drive a scara robot.
You might consider a smoothieboard. It has (potentially) functional SCARA code that you can peruse here:
True. As far as I understand it has morgan scara support, which is different, but close to plain scara. I’m actually focused on design and construction, and RAMPS was the cheaper and handy, but smoothieboard could be a better, powerful hardware option for sure. I’m out of money for this project actually, but would love to try smoothieboard at some point.
Maybe you can ask Nicholas Seward about his scara code? He built something very similar: https://hackaday.io/project/21355-reprap-helios and https://github.com/NicholasSeward/proto_RepRap_HELIOS/tree/master/Smootieware/src
Thank you very much for the tip, I was not aware of such nice project. Maybe I’ll try that firmware if I ever get a smoothieboard.
Seem to be a lot of pointers to open source driver boards with SCARA support in the comments here: https://hackaday.com/2018/09/13/wood-shines-in-this-scara-robotic-arm-project/#comments