Difference: BikramAdhikariLab2 (1 vs. 2)

Revision 22014-02-07 - BikramAdhikari

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Lab 2

In this lab, we design 3 puppets that can actuate at 1mm, 10mm and 100mm. Given below is a description to each individual action puppets
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Basic Actuation

In this lab, I am adding a motor actuator to move the puppets from Lab 1.
 
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1mm Poker Puppet

This actuator is based on eccentric cam mechanism. There is a lever attached to the top of the cam shaft. This lever can only move in a distance ranging between minimum and maximum radius of the cam shaft. I have designed the difference to be approximately 1mm. This lever has a pen connected to it which bores on to the base plate.
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Design Process

In the design phase, I began with an intention to actuate the 100mm arch puppet such that it could draw some variations of arch on a board. I added a servo motor to one of its link, then started to obtain some variability in motion. While varying the motion, I observed an interesting behavior actuated like a bird picking something from the ground. It was obtained by moving the links back and forth to obtain a certain kind of arch based on trial and observation. The speed of the servo motor was varied in a certain fashion. At the end of the arch that takes the link from air to the table floor, a slightly faster speed of the servo gave a feeling of quickly picking up something as if like a bird.
 
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>		Now, if it was a bird I wanted it to not only move its head but have a tail or something at the back to flutter while its picking. Then came the idea to use 10 mm puppet with a long linear actuator to plug into one of the shafts of the actuated arch puppet. And here it is.
 
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<		When the cam shaft rotates, the lever oscilates within 1mm distance. This oscillation is transferred as linear motion on to the pen. This pen only pops out (or pokes out) of the base plate when the cam shaft is at its minimum diameter position. These two extreme cam shaft positions are shown in the images below.
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>		And a video here: http://www.youtube.com/watch?v=ysG890BNLlc&feature=youtu.be
 
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<		See video here: http://www.youtube.com/watch?v=2-08aaWPc2M&feature=youtu.be
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Reflection

 
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10mm Pen Puppet

This design transfer small circular motion to linear action. The total displacement is about 10mm. The rotatory shaft can rotate on one direction until the string is completely unwounded from the shaft. In the other direction, it can rotate only up to the position where the linear shaft's string lock is on its top. The rotatory shaft uses friction based locking mechanism to lock the linear shaft at a particular position. This design is inspired from traditional Nepalese instrument called "Sarangi".
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>		This lab was an interesting journey through design of a creature behavior using simple actuator. The end result used puppets designed in previous lab with an actuator having variability in speed and position as well as repeatability. This puppet converted an arch motion of a servo motor to a linear and a magnified arch motion.
 
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>		Now I am thinking to take this idea forward into developing this puppet with a feet and a head actuated to graze when its hungry during day. Stay tuned, in lab 3.
 
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<		In the following images, the two extreme positions of the rotatory shaft are shown. Correspondingly, we can observe the displacement of the linear shaft to be around 10mm.
 
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See Video here: http://www.youtube.com/watch?v=1uL_xB_lVZE&index=5&list=PLFNjF5XN33kHVeIN8pdtEKfSgrSi6UhiO

100mm Arch Puppet

This arch puppet transfer circular motion of small radius to an arch motion of larger radius. The small rotating link was designed to half approximately half the radius of large rotating link. The connecting link between the two rotating links is arbitrarily chosen. In this design, the spacing between to rotating links on the base was varied to achieve approximately 100mm arch motion.

Action:

This image shows puppet half way between two extremities. The end effector is a pen which draws on the paper as shown

See video here: https://www.youtube.com/watch?v=3G-MnAZegX0&list=PLFNjF5XN33kHVeIN8pdtEKfSgrSi6UhiO

  -- BikramAdhikari - 07 Feb 2014
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META FILEATTACHMENT attr="" comment="" date="1391792553" name="image1.jpg" path="image1.jpg" size="1129282" user="bikram7" version="1.1"

Revision 12014-02-07 - BikramAdhikari

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META TOPICPARENT name="BikramAdhikari"

Lab 2

In this lab, we design 3 puppets that can actuate at 1mm, 10mm and 100mm. Given below is a description to each individual action puppets

1mm Poker Puppet

This actuator is based on eccentric cam mechanism. There is a lever attached to the top of the cam shaft. This lever can only move in a distance ranging between minimum and maximum radius of the cam shaft. I have designed the difference to be approximately 1mm. This lever has a pen connected to it which bores on to the base plate.

Action

When the cam shaft rotates, the lever oscilates within 1mm distance. This oscillation is transferred as linear motion on to the pen. This pen only pops out (or pokes out) of the base plate when the cam shaft is at its minimum diameter position. These two extreme cam shaft positions are shown in the images below.

See video here: http://www.youtube.com/watch?v=2-08aaWPc2M&feature=youtu.be

10mm Pen Puppet

This design transfer small circular motion to linear action. The total displacement is about 10mm. The rotatory shaft can rotate on one direction until the string is completely unwounded from the shaft. In the other direction, it can rotate only up to the position where the linear shaft's string lock is on its top. The rotatory shaft uses friction based locking mechanism to lock the linear shaft at a particular position. This design is inspired from traditional Nepalese instrument called "Sarangi".

Action

In the following images, the two extreme positions of the rotatory shaft are shown. Correspondingly, we can observe the displacement of the linear shaft to be around 10mm.

See Video here: http://www.youtube.com/watch?v=1uL_xB_lVZE&index=5&list=PLFNjF5XN33kHVeIN8pdtEKfSgrSi6UhiO

100mm Arch Puppet

This arch puppet transfer circular motion of small radius to an arch motion of larger radius. The small rotating link was designed to half approximately half the radius of large rotating link. The connecting link between the two rotating links is arbitrarily chosen. In this design, the spacing between to rotating links on the base was varied to achieve approximately 100mm arch motion.

Action:

This image shows puppet half way between two extremities. The end effector is a pen which draws on the paper as shown

See video here: https://www.youtube.com/watch?v=3G-MnAZegX0&list=PLFNjF5XN33kHVeIN8pdtEKfSgrSi6UhiO

-- BikramAdhikari - 07 Feb 2014

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