Month: February 2012

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Building a Delta Robot Part 2: Build a theoretical model

2012-02-22 Dan

So I’ve decided what my robot needs to do in Part 1, and now I’m going to build a virtual model of the delta robot and program it there. That will give every user an intuitive visual GUI to the robot.  More importantly, the testing I can do in my model is testing I don’t have to do with expensive robot parts.  As a consequence, that means the model has to match real life as accurately as possible.  That means making a model of every part; linking the parts together in the computer; making them move around; check for collisions, study strain & breakages; and then the Success Tests from Part 1.

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What are “steps per turn”?

2012-02-22 Dan
Dear Dan,
Recently I am working on the Delta Robots. I look your forward and inverse Kinematics of the delta robots and it help me a lot.
In your application of forward and inverse kinematics there is a term “Steps per Turn” and this term in controlling the resolution.
What do you mean by this term ?
I am implementing this kinematics in MATLAB. How I can implement this “Steps per Turn” in my code or how I can calculate the resolution in my case.
Thanks
Regards,
Zeeshan
I use three NEMA17 stepper motors to control movement of my robot.  Hobby servos have 256 positions in 180 degrees.  My steppers have 3200 steps per turn. I calculate resolution as distance tip moves when servo makes one step.  Better would be to calculate all steps at all positions and find max/min but this is javascript and it would probably kill your browser.  I have some code in the open source project that calculates the exact shape of the envelope.  It could easily be expanded to calculate the min/max step (which might not be the same size everywhere in the envelope).
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Drawing Lines, Arcs, and Halftones with a Wall Hanging Arduino Drawbot

2012-02-13 Dan

Download the code here

2013-11-26: updated link to github project!

Among the various features are…

  • Verbose output: Debugging line and arc drawing took a lot of work and I see no reason to remove all the helpful debugging messages.  Maybe it will give you insights to my madness.  uncomment #define VERBOSE to see the storm of messages in the serial interface.
  • Serial command interface: Type commands to the drawbot and it will execute them.  Draw all the arcs & lines you want.  Write a javascript app to send whole SVG files to your drawbot.  Don’t worry about mistakes because I’ve added
  • Sanity checking: Try to send the drawbot out of the work envelope and it will refuse with a cryptic error message.