Glossary · Robotics
Singularity
Also known as: Kinematic singularity, Singular configuration
German: Singularität
In robot kinematics, a singularity is a configuration in which the robot loses one or more degrees of freedom of tool motion, for example when two joint axes line up; near it, small tool movements require very large joint speeds and the joint positions for a pose are no longer unique.
- Robotics
In one sentence
A singularity is a robot pose where joint axes align and tool motion loses a degree of freedom, so joint speeds can become extreme.
Example
When the linear path passed straight through the wrist singularity, axes 4 and 6 spun rapidly and the controller stopped the robot with a speed error.
How it applies
- Engineering: Six-axis robots have wrist, shoulder and elbow singularities. Path planning avoids them by adjusting tool orientation, moving the part or using a redundant axis.
- Commissioning: Controllers either slow down, reject the path or stop with an error near singularities. Programmers must recognize the error messages and reteach positions.
- Documentation: The documentation team should explain singularities in programming guides with a picture of the typical poses, describe the controller's reaction and messages, and mention that unexpected fast axis motion near a singularity is a reason to stay outside the robot's reach during testing.
Singularity vs. workspace limit
A Workspace (robot) limit is where the robot cannot reach. A singularity can occur well inside the workspace, where the robot can reach a point but cannot move freely around it.