Two Arm Drawing Robot

I was recently requested to program an Arduino + MATLAB based 2-Arm Drawing Robot last month for a summer camp. Something like the TRS Drawbot.

The TRS Drawbot has two motors that are controlled by an audio signal. Images are encoded by a software into audio files that can be played on any device. Instead of making this version, we’re going to use one that uses an Arduino and MATLAB for control, similar to this Drawing Robot. The instructable article is a few years old, MATLAB has updated its Arduino support, and the article has code that I don’t consider easy to understand, so write some code from scratch.

We had Eric Bishop 3D print and build the robot for us, which looks like the photo to the right.

Note the angles on motors M1 and M2. The zeros are important, otherwise the robot will not draw correctly.

Implementation Note: We will build the robot with M3 detached. Once M3 is connected, the height of the motor limits the robot from reaching (M1, M2) = (0,0)

Another example shows the robot in the (90,90) configuration. Note how the forward dynamics for M2 are relative to the M1 arm (and not fixed in world co-ordinates).

Hardware Build

I don’t have all the details for our 3D printed hardware build, but the ones at the Drawing Robot Instructable should suffice.

Once you have you have your hardware ready, its time for some forward dynamics and testing if the robot works as expected.

Forward Dynamics and Testing

(Coming soon…)