03. Degrees of Freedom

Degrees of Freedom

The phrase "Degrees of Freedom" (DoF) refers to the minimum number of variables that are required to define the position or configuration of a mechanism in space. Check out the following quizzes to get an intuitive understanding of what DoF represents and how it relates to a robot.

Point on a line

For a point (p1 above) that can move along a line, how many coordinates do you need to specify to describe its position?
SOLUTION: 1

Point on a plane

What about a point that can move about on a plane? How many coordinates are required to specify its position?
SOLUTION: 2

Two points on a plane

How about two points on a plane? How many coordinates are required?
SOLUTION: 4

Two connected points on a plane

Now what if we connect those two points with a rigid rod? How many coordinates do you need to describe this new system of two connected points on a plane?
SOLUTION: 3

Two points on a rod with one end fixed

Now what if we anchor the system on an axis at one of the two points (p1 in the image above), so now p1 is constrained to a fixed position and connected to p2 with a fixed length rod. How many degrees of freedom does this system have?
SOLUTION: 1

#### Is this system starting to remind you of something??

Is this system starting to remind you of something??