Space arm
Technical · February 2023
RevolutionUC 2023
Kinetic Vision came to RevolutionUC with a challenge: they had joint data for a Kuka 7-node robot arm sitting in MATLAB files, and they wanted a way to actually look at it. Me, Kaaustaaub, Alexander and Akhil took that one.
We built a browser page where the arm sits in 3D, you drag sliders for each joint, and the end of the arm goes where the math says it goes. It reads their CSV data and can play back pre-built movement sequences. We also registered howardgotinastickysituationwithspacearm.tech for it, which won Best Domain Name, and I maintain that award was earned.
Kinetic Vision gave us their Robotic Data Visualization award, and two hackathons later I'd end up doing their 3D printing challenge too.
the kinematics
My part was the movement logic, which meant learning inverse kinematics in a weekend.
Technical
Forward kinematics is the easy direction, angles in, position out. Inverse kinematics is the one the challenge actually needed, give me a target position and solve for the seven joint angles that reach it. With seven joints the system is redundant, there are infinitely many valid poses for most targets, so the solver has to pick one and not flail on the way there.
We built the arm in Unity from OBJ models made in Blender, Fusion360 and RoboDK, then exported the whole thing to WebGL so it ran in a browser with nothing installed. The IK solving and the slider-driven forward kinematics both ran against the same joint model, so the CSV playback, the sliders and the target-reaching all agreed with each other.
