Two-Link Planar Robot Arm

A two-link planar arm is probably the simplest machine one can build that still teaches real robotics math. In this video I walk through every step: 📐 CAD design in Onshape — motor mount designed using the boolean subtraction trick 🖨️ 3D printing & assembly 🏠 Servo homing & calibration — using a built-in firmware command to set the center position 📐 Angle conversion (servo ticks ↔ radians) ➡️ Forward Kinematics — deriving pen tip position from joint angles using trigonometry — verified with a ruler on paper — for more complex chains, look up "Denavit-Hartenberg parameters" ⬅️ Inverse Kinematics — deriving joint angles from a target position — the elbow-up / elbow-down ambiguity — for complex arms: iterative methods & machine learning approaches 🟥 Drawing shapes — interpolating waypoints along each edge to get straight lines The math here isn't a toy version — it's exactly the same kinematics used in industrial SCARA robots. A SCARA just adds a Z axis and wrist rotation on top. 📌 Chapters 0:00 Intro 0:25 Designing the parts in Onshape 1:14 3D printing & assembly 1:31 Servo calibration 2:13 Angle conversion 2:29 Forward kinematics 3:30 Inverse kinematics 4:14 Drawing demo #maker #robotics #3dprinting