11. Soft robotics#

Unlike rigid robots we are mostly used to, soft bodied robots have similarities and performance characteristics similar to living organisms or the human body. Soft-robotics are based in Bio-inspired design or biomimicry and have applications in wearables, rehabilitation prosthetics, surgical robots, rescuing and others. We will focus on the fabrication of soft actuators, sensors and grippers using novel materials, artificial muscles and performative locomotion design.

‘Octobot’ is the world’s first soft-bodied robot

Main idea#

Algae are the main inspiration for this project! While I was learning about soft robotics, the first thing that came to my mind was algae and life underwater. I automatically associated soft robotics movements with the algae I’ve seen while scuba diving. They move with ease, have amazing colors and textures. Moreover, most of them are extremely soft!

Algaes have so much potential and still almost virgin when speaking about scientific studies, aplications and their properties. The idea was to create a reflexology mask, that at the same time that moisturizes skin, it inflates and so make pressure on specific points of the face that help to relax and to recover from migraines (I suffer them, and the best thing to go over it is to massage your face).

Reflexology face points to pressure

Yvette Eastman's reflexology face map

I wanted to make it out of agar based bioplastic, with natural aloe vera gel to have both plants properties and then be good for the skin. Also add spirulina powder to make it green at some areas (the once that inflate) and chia seeds, and so it will look like the algae microscopic view as well. After some research, I found out that it won’t work with agar bioplastic because it shrinks and doesn’t stick to other layers of it. As for my mold, I need to pour 3 different layers and then stick them together with the same mix of bioplastic. The first one is the air conduct, the second one the bottom of the ‘bubbles’ and the last one the top of them, and the layer that will be made out of the customized bioplastic (with spirulina and chia seeds as an additive).
So I decided to make it out of gelatine, with which it is supposed to work. Though as there’s not much time to do it with this materials and wait till they dry, so I did samples of it with silicone and see how it works.

I also want to share with you the work of an artist I found while doing research on algae. He is Jason deCaires Taylor. He does sculptures in what they called underwater museums. He cares about environment, art , activism and marine ecologies, and his work came to be known as earthworks or land art. His art addresses social issues such as poverty, addiction, capitalism or equal rights. So I felt identified with his values as well as loved his work!

“Each day, habitats are destroyed, whole species are lost and climate change alters the living conditions across the world. Small changes can be made that can ultimately have a big impact, the first step of which is bringing about environmental awareness of the conditions of the various ecosystems around the globe” - JamesdeCairesTaylor

Some of his underwater sculptures, after some years submerged, were amazingly covered by algae and corals.

Research#

Algae dominate the oceans that cover nearly three-quarters of our planet, and produce half of the oxygen that we breathe. And yet fewer than 10 percent of the algae have been formally described in scientific studies. Algae are everywhere. They are part of crusts on desert surfaces and form massive blooms in lakes and oceans. They range in size from tiny single-celled organisms to giant kelp.

Algae (singular: alga) are photosynthetic, eukaryotic organisms that do not develop multicellular sex organs. Algae can be unicellular, or they may be large, multicellular organisms. Moreover, algae can grow in salt or fresh waters, or on the surfaces of moist soil or rocks.

Algae date back over billion years and some of the first plants on earth evolved from algae. Green algae are by far the most complex group and have led to the evolution of land plants. Their simple structure means they are lacking many anatomical structures that true plants have, specifically organs, and so sexual repoduction. Algae do not have true roots but attach to the substrate by rhizoids and rhizomes.

Some species, particularly brown algae, contain gas bladders to keep them afloat. Some algae have a symbiotic relationship with its host so that the photosynthetic products are used by the host for energy, while the host protects the alga. In a coral reef structure these are primarily algae of the Dinoflagalatte phylum and the alga living endosymbiotically with the stony corals are called zooxanthellae. The loss of this algae is what is known as ‘coral bleaching’

Some of the latest molecular techniques have allowed scientists to elucidate major genetic processes that have shaped algal evolution. And this improved knowledge has implications beyond basic scientific discovery. In the future, algae may be used to produce biofuels or to synthesize high-value therapeutic compounds or plastics.

Many studies have shown that algae can also adapt to changing environmental conditions. But how will the effect of climate change on the world’s oceans impact algae and the oxygen that we derive from them?

“In the process of reviewing the state of algal research, we feel that we are on the cusp of a revolution in understanding this group of organisms, their importance in shaping ecosystems worldwide, and the ways in which they can be used to enrich mankind” said Arthur Grossman in Trends in Plant Science. - Trends in plant science -

“In the process of reviewing the state of algal research, we feel that we are on the cusp of a revolution in understanding this group of organisms, their importance in shaping ecosystems worldwide, and the ways in which they can be used to enrich mankind.”

Molds#

They are the first thing you need to do. Design it on Rhino and then 3d print them. I started with a 2d swatch on vinyll, which I designed on Rhino and then laser cut it in kitchen paper to work as the air flow, as both layers won’t stick in this area. This is how it looks like.

What I took out of the vinyl sample was that I should do the air flow bigger and shorter, and top ut my bubbles closer. Though the vynil wasn’t sticking good and many other bubbles were left, as I iron it and didn’t do it with a heat press. Still it was enough to emprove my design.
Then I did it 3d. One of the molds has the air flow for which I used pipe command creating it out of a curve I draw first. It is important to stick to 0,5 cm of diameter, so the air flows correctly inside of it. Also I contain it into walls of 0,75 cm height, (extrude command out from a rectangle curve), as I need some extra height to ‘close’ the conduct and then keep the air inside. Boolean split, boolean difference and boolean unión where important commands I used to put it all together.


The other mold was a little bit more complex. I did my ‘bubbles’ with Sphere command, and some pipes to guide the air flow from the pipes of the other mold to the bubbles in this one. Also I contain it into walls of 0,70 cm height, (extrude command out from a rectangle curve), as I need some extra height to ‘close’ the bubbles and then keep the air inside. The third layer/mold consists on this bubbles made out of a thick layer. So I just extrude the 2d circular curves I did for the vinyl test.


Advices & things to have in mind:

√ Both layers/molds have the same size in x and y. So after sticking them, they will look like one piece.

√ Be aware of the air conduct size.

√ Vacuum the silicone/bioplastic mix till you see there’s no more air inside of it, so it doesn’t modify the air flow later.

√ I recommend you to do your mold out of filaflex so you can bend it to take the mix out. Though I’m a bio freak and tried to use the less harmful material for our environment, in this case my best option was PLA, but it was hard to take it out of the mold.

√ Be sure your shapes are closed and full, or watch out top ut the infill while setting the 3d printer. If not, ask someone that’s experienced with 3d printing if it will print good or melt as mine. Then I closed them and print it again.

Soft Robotics molds by larracampos on Sketchfab

I wanted the spheres to be empty on the inside so I took the infill setting, in order to experiment inflating the mold afterwards (after submerge them in hot water). I took this idea from Aera Fabrica Project. You can take a look of it here:

AERA FABRICA | process video from Studio Roos Meerman on Vimeo.

Casting#

While using silicone is important to read the instruction sheet of it, to be aware of the process and the time you have before it dries. I’ve used Ecoflex 00-30, and it dries quite fast!! But its a good choice if you want your mold to be very flexible and so it inflates easy. I mixed the two components for it, vacuum the mix till you see there are no more bubbles going out of it (2 mins in this case) and then pour the mix into the molds.

Finishes#

Let them dry at least 4 hours (check the instruction sheet of the material you are using), and then remove it from the mold. Stick the different layers with a little bit of the same mix and let it dry again. Then your inflatable is ready and you can improve the mechanism setting an air motor with the arduino, or any specific sensor you want to add to your soft robotic.

Results#

This is the final result!

This is the result of the first sample. It’s not what I expected, but out of my experimentation some things failed. In this case, the mistake was to add different materials to the silicone that where more dense than the silicone and so came down creating some holes in the piece. So have that in mind if you are doing yours!

Soft robotics fail from Lara Campos on Vimeo.

This are nice pictures about another failed test with paint. Here you can see clearly how holes created when stretching the silicone.

I’ve fallen in love with algae microscopic views and want to share them with you. Think about how beautiful nature can be. It is just the prime art, where all shapes already exists.
-mother nature-