Glossary
Degrees of freedom (DOF)
The number of independent coordinates needed to describe a robot's configuration, such as joint angles or sliding positions, after accounting for mechanical constraints.
Also known as: DOF
A simple hinge permits one independent rotation, while a sliding joint permits one independent translation. A joint can allow more than one motion, and links connected in a loop can constrain one another. Counting motors or powered joints therefore does not establish the mechanism's DOF. Use DOF to understand which motions are possible; a larger count alone does not establish how well a robot will perform a task. When comparing specifications, check which parts of the robot the stated total includes.
Read a robot specification with this in mind
Does the total cover the body, the hands, or both?
- Which model and configuration does the number describe?
- What does the source include or leave out of its total?
- What task evidence accompanies the specification?