8. Soft robotics¶

Soft robotics¶

Research¶

What are Soft Robotics?

In brief soft robots are a type of robot that is designed with flexible and softer materials, unlike traditionally designed robots that are rigid and made from stiff materials. Soft robots, because of their flexible and compliant bodies will not cause harm when they come into contact with another object or body, as well as they themselves will not break easily. Moreover, soft robots can be the whole mechanism, as well as a part of a rigid robot, for example soft robotic tentacles can be attached to a robotic arm, giving it more flexibility and capability to grab things.

Soft robots are often biocompatible and adapt to the environment they are in or interacting with. They often operate with air or liquid pressures, as well as electronic signals. They are awesome!

_{Credits to Zhanchi Wang}

Thee most grabbing part of soft robotics for me is that they are, more often than not, inspired by nature for nature. If you have the time, watch the video below for a deeper understaning of how they work and how they are made and what for..

References & Inspiration¶

This week was the first time I actually looked at soft robotics, so it was both a week of many “news”, yet at the same time it was a week of working with programmes and machines that we had already used before. How they moved, how they acted kept reminding me of worms.. Which I suppose isn’t surprising. So initially I decided to research different worms and to study their movements. However, very quickly I had to stop. Worms are difficult for me to look at and I was starting to feel icky. So I went to something that soothed me - marine life. Having grown up by the sea, I guess I also felt a little homesick.

Spirobs¶

Spirobs, a project developed by Zhanchi Wang and Nikolaos M. Freris at the University of Science and Technology of China, is a beautiful example of soft robotics. It is a "bioinspired universal design principle based on the logarithmic spiral, fast and low-cost fabrication based on 3D printing with TPU, with a simple actuation mechanism by two or three cables. A simple design that does complex things.

OmniFibre¶

Another very inspiring and exciting project is the soft robitics fibre developed at MIT Media Lab, called OmniFibres. This inexpensive yet complex fibre can be made into clothing that senses how much it is being stretched or compressed, and then provides immediate tactile feedback in the form of pressure, lateral stretch, or vibration. Such fabrics, the team suggests, could be used in garments that help train singers or athletes to better control their breathing, or that help patients recovering from disease or surgery to recover their breathing patterns.

This week, of course was the first time I was thinking, calculating and designing my own soft robotics. While projects like the OmniFibre are inspirational, it has not influenced my own soft robots directly, but this research and developemnt has given me a food for thought.

Fabricademy Alumni inspirations

Process and workflow¶

At the beginning of the week we started looking at vynil cuts available at the lab, inflating them and understanding the very basicas of the process. We then proceeded to cutting a form using Roland vynil cutter, as well as laser cutting parchment paper that would be placed between the two vynil cuts, then ironed.

_{Photos by Svetlana Khachatryan}

Note: Make sure that the bottom tail of your 2D design is wide enough for the air tube to fit and to be ironed from the sides.

This week I began my design with a simple 2D of corals using illustrator.

Vynil Cut¶

At Fab Lab Dilijan, we have a Roland CAMM-1 Servo GX-24 vynal cutter and I will guide you through how to use it.

Step 1

To insert the vynal, you need to press on the lever at the back of the cutter so the rollers lift up.

_{Photo by Svetlana Khachatryan}

Step 2

Once you have put in the vynal roll, piece or sheet you need to make sure that the rollers are where there are white marks.

_{Photo by Svetlana Khachatryan}

Then you can put the lever back up and lock the vynal roll in its place.

Step 3

You can now press the switch button on the monitor and select the sheet type you are using to measure the dimensions of your piece of vynil. From the Menu - Material Setup- select Piece and press ENETER. On the monitor you will see the exact dimensions of your vynil.

_{Photo by Svetlana Khachatryan}

Step 4

You need to now cut a test piece to make sure that your settings for blade depth and cutting force are correct. To do so, you need to press the TEST button. Roland will automatically cut a small piece, which you can then check with a twiser and see if it has cut through the vynal but not the sticker behind it.

Note: You can adjust the force by pressing on the FORCE button and increase or decrease the force using the arrows. Once done, you can press ENTER and go back to the main menu.

Cutting Settings

Speed : 20 cm/s
Force: 130 gf
Blade offset: 0.25 mm

Step 5

To be able to print a file you need to connect the lap top to the Roland vynal cutter and using CorelDraw, you can press print and select the Roland GX-24. On the left side there is a properties/settings button ⚙︎, which you can press and change the dimensions of your Cutting Area. To do so, you need the exact dimensions, which you can upload by pressing Get From Machine. When ready, start cutting!

When finished cutting you need to exit the setups by double clicking on MENU button. On the screen UNSETUP will appear, you can press ENTER and your vynil cutter will go back to its basics.

Fab Lab Gyumri¶

We actually went to the Fab Lab at the Academy of Fine Arts of Gyumri the next day to demonstrate the processes of vynil cutting and making inflatables there. I had the oppertunity to continue working on my designs there.

To cut the 2D design of the coral illustration on parchment paper I used their open source laser cutter OLSK Small Laser. To align the beam of the OLSK Small Laser, you need to use the focus tool, by placing it over the material that you want to cut and adjusting the laser head by moving it up or down until it slightly touches the focus tool. Once the laser is focused, then you can remove the focus tool.

We adjusted the settings:

Speed: 100 mm/s
Power max: 25%

After cutting the vynil parts, I was ready to experiment.


_{Photos by Svetlana Khachatryan}

Using the hot press available at the lab, I was able to do the finishing touches before it was ready to be inflamed.

Hot Press Settings

_{Photo by Svetlana Khachatryan}

Note: Make sure that when you are using the hot press, you do not press the parts where the tube must go in from. Press the edges if you can, or use an iron if it will be easier to control which parts you are applying heat to

Final Rsult¶

I wanted to immitated the slow movements of the coral and I think this was a successful test!

Molds and Silicons¶

To have a better understanding of how soft robots are made we also experimented and used the molds already available at the lab. Mixing the two parts of silicone gel together needs a lot of attention. You must use EQUAL parts of A and B components of the silicone, and carefully, slowly mix them together (at least 7 min) not to introduce air bubbles. Depending on the mold design, you can use different shores (hard, soft, very soft). I used equal parts of A and B with 05 shore silicone gel. If any bubbles do occur, you can pop them with a needle and give your molds a little but of a vibration.

Note: shores detirmine the softness or hardness of the silicone after it dries


_{Photos by Svetlana Khachatryan}

Once the silicone has dried you can carefully take them out of the mold, mix more of the same silicone gel (with the same shore) and "glue" them together. If you check on your molds but the silicone is still wet the next day, then it will not dry. It can be anything from how A and B components are mixed together, not using exact euqal parts, silicone gel being old etc.


_{Photos by Svetlana Khachatryan}

Designing Molds¶

Since my inspiration for the week was the marine life and my coral experiment with the vynal cut was a success I decided to design two more potential soft robots.

Sea Shell¶

_{Photo by Content Pixie}

There is something very beautiful about the symmetry of the sea shell. It is after all the symbol of the Golden Ratio. A symmetry that occurs in nature, fostering an organic composition when used in designs. I decided to work on a mold inspired by the absolute symmetry of the sea shell, giving each length a calculation that was symbolic to me.

How this was going to work, curve or inflame I was not absolutely sure. When designing the laser cut files, it is important to make the lines into 'hairlines'.

Coral¶

The design I did to experiment with vinyl for the beginning of the week was also made into a mold, then filled with silicone gel - shore 05.

Fabrication files¶

File: Coral
File: Sea Shell
File: Pearl Shell