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### Author Topic: Difference Between A Cylindrical and Screw Joint  (Read 2596 times)

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#### arafatasghar

• Beginner
• Posts: 1
##### Difference Between A Cylindrical and Screw Joint
« on: November 04, 2014, 09:54:34 AM »
Hi Everyone,

I am a new entrant into the field of robotics and familiarizing myself with some basic concepts about space configuration. While reading about joints and their associated degrees of freedom, I came across cylindrical and screw joints. Now both have rotational and translational motion yet the cylindrical joint has 2 DOF while screw joint is classed as having only 1 DOF. Why is this?

P.S I would really appreciate if someone referred some online educational resources that would help clarify the whole concept.

#### mklrobo

• Supreme Robot
• Posts: 558
• From Dream to Design at the speed of Imagination!
##### Re: Difference Between A Cylindrical and Screw Joint
« Reply #1 on: February 19, 2015, 08:13:49 AM »
Hello! I would offer an opinion.

screw joint is a one-degree-of-freedom kinematic pair used in mechanisms.[1] Screw joints provide single-axis translation by utilizing the threads of the threaded rod to provide such translation. This type of joint is used primarily on most types of linear actuators and certain types of cartesian robots. [2]

A cylindrical joint is a two-degrees-of-freedom kinematic pair used in mechanisms.[1] Cylindrical joints provide single-axis sliding function as well as a single axis rotation, providing a way for two rigid bodies to translate and rotate freely. This can be pictured by an unsecured axle mounted on a chassis, as it may freely rotate and translate.[2]

This information was taken from Wikipedia. Good starting point, hope this helps!