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jasonwebb / loogie-robot-arm

Restoration of a D&M Computing Armdroid 2001 robot arm for use in experimental digital fabrication, generative art, and interactivity research
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Investigate existing open-source closed loop controller options for gearmotors #5

Closed jasonwebb closed 5 years ago

jasonwebb commented 7 years ago
Name Unit cost Channels Current (cont.) Current (max) Qty Total cost
Tarocco $45.00 1 10A - 5 $225.00
Pololu Jrk 21v3 $49.95 1 3A 5A 5 $249.75
RoboClaw 2x7A $69.96 2 7.5A 15A 3 $209.88
Leadshine DCS303 $65-120 1 3A 15A 5 $325.00+
jasonwebb commented 7 years ago

Financially it would make the most sense right now to buy two RoboClaw 2x7As and one Tarocco, but I need to warm up to the idea of mixing platforms. It may make sense to use two RoboClaws for the 4 main axes of movement, with the final axis (wrist rotation?) being run by a Tarocco.

It may be feasible to DIY a batch of Taroccos at a vastly lower unit price. I may need to invest in some basic SMD reflow tools, which I'd like to do anyway for multiple projects.

I'll create a priced-out BOM of the Tarocco parts (with PCB estimate) and see what the difference is.

I'd also like to investigate the possibility of designing a custom all-in-one board that integrates multiple Taracco boards into one, similar to how boards are designed for 3D printers. May be limited by electronics CAD, though, we'll see.

jasonwebb commented 7 years ago

After thinking it over a bit, going through all the labor and time involved with DIYing custom Tarocco boards, I don't think it'll be worth the savings of roughly $15 compared to buying three RoboClaw 2x7A boards.

I will plan to purchase these boards once I have tested and verified the current ratings of the robot's motors.

jasonwebb commented 5 years ago

In issues #6 and #16 I learned (and experimentally verified) that the maximum current draw of most of the motors is about 1.4A, and 1.76A for the wrist rotation motor. This means that even the "weakest" motor drivers I found earlier are sufficient for this project.

The RoboClaw 2x7A stands out to me as the best option not only for it's low cost, but also for it's features and software/firmware interfaces. I'll go ahead and order them once I've progressed a little more on other parts of the bot.

Before ordering the drivers, I'm going to figure out how to replace the missing timing belt (#14). No point buying fancy electronics if the bot can't move!