Author Archives: anita shah

Spinal Movement Week 6-7

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In this week I developed a new design for pneumatic curling. Instead of the spines being internal, I tried to extrude them. First I developed a CAD model for the mold which ended up being split into three parts:

When constructed the parts look like this for the mold:

Finally after the silicone has cured and been removed from the mold, it looks like:

The movement of this mold is much more extreme than the previous design. Specifically it appears to take much less air to cause a full curvature of the silicone. Also of note this design appears to be more manageable for air leaks and fixes, and the air channels are less likely to clog. Overall, however, the need to remove air bubbles is crucial for both this design and the previous silicone designs, as air is most like to alter a uniform distribution and focus to weak areas of the silicone.

Spine Movement (Week 4-5)

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Pneumatics Progress

These past couple weeks I designed and 3D printed two separate molds for soft bodies. One is a gripper (obtained from instructables with some slight alterations), and the other is just a tube like body with an air chamber in it. The first is to test movements as a result of different air chamber architectures, how much air push is necessary, how loud the movements are, etc. The second is to test another concept I found called fabric reinforcement, where by wrapping fabric along the outside of the body in different patters, one can obtain different movements.

 

1). The Gripper:

Here is an image of the 3D printed mold:

Video to Come

2). The tube movement WITHOUT fabric reinforcement:

Here is an image of the soft body mold:

Here is a video of the mold moving (with sound) when air is blown into it:

3). The tube movement WITH fabric reinforcement:

Here is an image of the soft body mold:

Here is a video of the mold moving (with sound) when air is blown into it:

Summary of Results:

This seems like a completely viable option to pursue for movements, however I will need to be very strict in my architecture and soft body creation to get the exact movements that I want. In terms of the fabric reinforcement, there is certainly some viability to this idea as the video shows the beginning of a “twisting” motion due to the wrapped string. More research will be needed to to discover exactly what patterns/ degrees of angles are needed to get particular movements.

 

Spine Movement Week 3

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New Direction (Air Chambers)

After Paul mentioned that he liked how the sponge was “squishy” and the concept was a lot less “skeletal” than previous cuddlebots with spinal-like movements, I decided to pursue this direction. It was through some research this week that I decided to pursue the idea of soft-bodied robots. In particular the concept of pneumatics, where one pushes air into silicone based bodies to cause a wide range of movements. In pursuit of this, I find an instructable to start on:

http://www.instructables.com/id/Air-Powered-Soft-Robotic-Gripper/

I will continue to work on this idea for the next few weeks to see if this is a viable idea for movement.

Spinal Movement Prototype A Improved

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Following the previous week’s thoughts, for this prototype I tried to incorporate some type of resistance in between each of the vertebrae. For my initial pass I tried a combination of springs and various foams.

However, based on the results the wires were getting “stuck” and the shape was not returning back to it’s stationary position. In consultation with Paul, we decided to move forward with the foam material, but to drill channels into them for the wires to go through. The results are indicated below.

 

Summary

The foam material seems to work perfectly, I also like that the channels hide the wires. A servo base will need to be constructed for the bottom “vertebrae”, but this will be attempted farther along when more med-high fidelity prototypes are called for. Since this prototype still doesn’t afford the freedom of movement of “twisting” the spine, this movement will be my next big pursuit along with the idea of spinal fins that move independent of each other. This will be further explored next week.

 

Spinal Movement Low-Fi Prototype A

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First step that I took was to create a mood board of spinal images/designs that inspired me:

I then drew out some sketches of what some spinal movements could look like, focusing on prototype A to follow through on today:

I then quickly created a low-fi prototype of what this could look like in a physical form using tape, plastic sheeting, and some joint connectors made via mecho parts:

I used some string running through each part to guide the horizontal rotation around the joints (using a single fastener at only the top of the prototype).

 

SUMMARY:

In order to get the type of fine-tuned motion this prototype needs to be adapted so that EACH “vertebrae” is capable of moving independent of the other. This could be accomplished by having a thread fixture at each of the vertebrae instead of only having one fixture at the top and then looping said thread through all of the lower vertebrae. Also there needs to be some mechanism that restores the original spacing between each of the vertebrae. I believe this can be accomplished via springs and/or sponges.