What are robot singularities?

The typical six-axis industrial robot arm has three types of robot singularity: wrist singularities, elbow singularities, and shoulder singularities. A wrist singularity occurs when the axes of joints 4 and 6 are coincident. An elbow singularity occurs when the wrist center lies in the same plane as the axes of joints 2 and 3. Finally, a shoulder singularity occurs when the wrist center lies in the plane passing through the axis of joint 1 and parallel to or passing through the axis of joint 2.

When a robot is controlled in Cartesian space and passes near a singularity, the velocity of some joints becomes suddenly very high. Contrary to a common misconception, all modern industrial robots are pretty much the same when it comes to confronting singularities, no matter how "intelligent" the robot controllers are. Sure, some robots can automatically deviate from the desired Cartesian path (a linear segment or a circular arc), but that's not always... desirable.

Another common misconception is to mix so-called representational singularities associated with Euler angles with robot singularities. These two phenomena are completely independent and different.

For further details, read our in-depth tutorial on robot singularities (https://www.mecademic.com/en/what-are-singularities-in-a-six-axis-robot-arm) and the one on Euler angles (https://www.mecademic.com/en/how-is-orientation-in-space-represented-with-euler-angles).

Видео What are robot singularities? канала Mecademic Robotics