
Deep dives 11 min
Denavit–Hartenberg, Completely: Building and Solving a 6-Axis Robot Arm
Build the DH table for a six-axis arm from its geometry, turn each row into a matrix, multiply through to the tool, and then run it backwards. The closed-form inverse kinematics is shown step by step: wrist centre, law of cosines, the wrist rotation, the eight solutions.
Then the places it breaks: the classic–modified mix-up, parallel axes, singularities, and calibrating the table against a real arm with a laser tracker.
In this video
- Frame assignment rules and the common normal
- Measuring d, θ, a, α on a real arm
- The 4×4 matrices and their closed form
- Forward kinematics to the tool, live
- Inverse kinematics in closed form, eight solutions
- Singularities and calibration