Introduction to Robotics
Myth vs fact
Do more joints always make a better robot?
Engineers often choose fewer joints on purpose. Here's why.
Quick check · tap an answer to continue
Lesson notes
Key points
- A rigid object in 3D space needs only six degrees of freedom, three for position and three for orientation, to reach any pose.
- Each extra joint adds cost, weight, failure points and more complex inverse kinematics, so many tasks use simpler four-axis SCARA robots.
Definitions
- Degree of freedom
- An independent way a body can move; 3D pose needs 3 translations plus 3 rotations.
Myth: A robot arm with more joints is always better.
Fact: The best arm has just enough degrees of freedom for its task.
Takeaway: Match degrees of freedom to the task, not to impressiveness.
Quick check: Myth or fact: placing a tool at any 3D position and orientation needs at least six DOF.
- Myth
- Fact
- Depends
Full pose needs three positional and three rotational freedoms.
Six DOFAdded complexity
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