Denavit-Hartenberg (DH) parameters
A standardized mathematical notation for describing the geometry of robot links and joints that uses four parameters per joint. This provides a systematic way to represent complex robotic structures.
Instead of writing out complex 3D geometry, engineers use just four numbers per joint.
The Four Parameters:
- Link length — distance between two joints along one axis
- Link twist — rotation angle between joints
- Joint offset — perpendicular distance between joint axes
- Joint angle — rotation at that specific joint
Why it matters:
- Systematic & compact — Rather than separately tracking the position and orientation of each part, DH parameters give a consistent "recipe" for building up the robot's geometry from base to end-effector (gripper)
- Mathematical power — Once you have DH parameters, you can easily calculate where the robot's hand is in space based on the angles of its joints (called "forward kinematics")
- Industry standard — Nearly all robots use this notation, so engineers can quickly understand any robot's mechanical structure
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