Degrees of freedom

Question 1

What is a planar mechanism?

Answer 1

It is a mechanism whose links have velocitity vectors that are parallel to the same plane (called plane of motion).

(Think in 2D!)

Question 2

What is an articulated mechanism?

Answer 2

Is a type of mechanism made up of kinematic pairs that belong to class 1.

Question 3

What is a kinematic chain?

Answer 3

Is a set of links connected by kinematic pairs.

A kinematic chain can be open or closed.

Question 4

What is Degree of Freedom of robot?

Answer 4

Is a term that describes a robot’s freedom of motion in three dimensional space.

Question 5

What is a mechanism?

Answer 5

A kinematic chain where the frame is defined.

Question 6

Give the Kutzbach equation (spatial mechanism).

Answer 6

n = 6(m-1) - 5c1 - 4c2 - 3c3 - 2c4 - c5

n = # DoF
m = # links - frame included
ci = # of joints of class i

Question 7

Gubler equation (planar mechanism).

Answer 7

n = 3(m-1) - 2*c1 - c2

Question 8

What is a kinematic diagram/scheme?

Answer 8

Is an illustration of the connectivity of links and joints of a mechanism or machine rather than the dimensions or shape of the parts.

Question 9

When the Gubler and the Kutzbach equations fail?

Answer 9

• Wrong application
• Redundant constraints
• Hyperstatic mechanism