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Four-Bar Polode Animation

5.0 | 6 ratings Rate this file 7 Downloads (last 30 days) File Size: 116 KB File ID: #30006 Version: 1.2
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Four-Bar Polode Animation


Don Riley (view profile)


11 Jan 2011 (Updated )

Animates all classes of 4-bar mechanisms, plots instant center paths, allows link length changes.

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The program is a graphical tool to visualize 4-bar mechanisms and the instant centers that are produced by the mechanisms, and plots the path of the instant centers.

The paths (polodes) of the instant centers are shown for the mechanism and the inversion of the mechanism (switching the coupler link and the ground).

The polodes represent two curves, that when one roles on the other, produces the same motion as the original 4-bar coupler that made them, e.g. the 4-bar can be synthesized by a 2-bar mechanism consisting of only the fixed and moving polode. The moving polode curve will have two points on it that travel in circles, just as the original coupler did on the 4-bar.

You can select from 15 different types of 4-bars, e.g. cranks and rockers or combinations of the two.

Also, you can specify any link length of interest, numerically or with slider bars, and do so while the animation is running (but hit the "change links" button.)

There is a slider bar to adjust animation speed and input angle specification. If you "stop" the animation, the input angle may be specified by dragging the slider to move the mechanism.

If you just want to see the 4-bar animate, uncheck all the boxes under "Display"

Lastly, two zoom options are provided.

Feedback for improvement or other ideas is welcome.


3 D Puma Robot Demo inspired this file.

MATLAB release MATLAB 8.0 (R2012b)
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Comments and Ratings (6)
07 Jul 2016 Harish Babu Kankanala

06 Jun 2013 Paul Kassebaum

29 Jul 2012 Richard Primerano

Very nice

16 Nov 2011 rakan

rakan (view profile)

good jop

30 Oct 2011 Brato CHAKRABARTI

12 Jan 2011 Don Riley

Don Riley (view profile)

This file was the final "project" that John Hawkins did in my Kinematics class. If you have an interest in Kinematics or mechanisms, please take a look.

He did an excellent job making polodes (or instant center paths) visible for a wide range of mechanism. I simply did a minor edit and submitted it.

12 Sep 2012 1.2

Updated to include an App file for R2012b

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