I was in your situation when I made that video, but DaemonMaker, my friend who studies Robotics, helped immensely.
I can't really add much beyond what DaemonMaker said because my focus is on stroke planning and automatic painting and most of my work runs on simulated brushes and simulated canvas.
I'm preparing my techniques for profit and publication and wouldn't disclose them on a public forum. However, there are other methods out there, to control the robot, such as those mentioned by Aaron Hertzmann in Algorithms for Rendering in Artistic Styles
We describe new algorithms and tools for generating paintings, illustrations, and animation on a computer. These algorithms are designed to produce visually appealing and expressive images that look hand-painted or hand-drawn. In many contexts, painting and illustration have many advantages over photorealistic computer graphics, in aspects such as aesthetics, expression, and computational requirements. We explore three general strategies for non-photorealistic rendering
This technology has been around for a long time and if you're mostly interested in the robot, you can use this instead of worrying about control.
Hertzmann's algorithm depends on comparisons between the canvas and the reference image. If you want to do it with a robot, you'll need a camera to photograph the painting before and after every brush stroke. You'll also probably need computer vision algorithms to negate lens distortion, align the canvas and reference images, and adjust color biases from the illumination.
It's good to see fresh interest in the subject.