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8. Soft robotics

Research

Soft robotics is a subfield of robotics that concerns the design, control, and fabrication of robots composed of compliant materials, instead of rigid links. In contrast to rigid-bodied robots built from metals, ceramics and hard plastics, the compliance of soft robots can improve their safety when working in close contact with humans. (wikipedia)

I'm very interested in how to create movement by different patterns and structure design of the soft robot's shapes, especially learning and being inspired by nature's morphology and interactions. I'm fascinated by wide scope of experimentations that this opens up, specially in convination with electronics and sensors.

ref_01

source: https://www.gmwgroup.harvard.edu/soft-robotics

Fig. 3: 3D tentacles with multiple sections. a) Three-sectioned tentacle with nine independent microchannels, each controlled independently by an external source of pressure. The inset shows the cross section of the tentacle with the tubing traveling along the PDMS central channel. b) Schematic describing the distribution of the tubing inside the tentacle (not to scale). c) Tentacle with three sections inflated simultaneously. d) Tentacle holding a flower by conforming its three sections to the flower. e) Tentacle holding a horseshoe-shaped object. f) Tentacle with four sections holding a complex shape.

References & Inspiration

I've learnt the most from the Soft Robotics Toolkit website, developed by the Biodesign Lab at Harvard University and Trinity College Dublin.


Tools

  • [Soft Robotics Toolkit] (https://softroboticstoolkit.com/)
  • [Hardvare University - Soft Robotics] (https://www.gmwgroup.harvard.edu/soft-robotics)

Process and workflow

understanding inflatable principles

First of all is to make some shapes and cut them on vinyls to heat press and inflate to see how things work. So we make some tryout on vynil:

  • draw and cur your shape on baking paper

  • draw and cut your shape on 2 vynil sheets

  • put the baking paper in between the sheets, the vynils with the glossy sides looking out

  • heat press

  • let it cool

  • peel the glossy film layer

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how to: vinyl test

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vinyl tests

Making the mold !

I wanted to continue to drive inspiration from week #3 research into bacterial patters, so i made a drawing out of that research and put it into rhino to work on the different walls and shapes it should have. Both on Rhino and with Grasshopper i managed to print 3 different molds, two with PLA on the PRUSA 3D printer, and a thrid ona by glueing layers of methacrylate that have been cut on the laser cut.

step 1: Rhino + Grasshopper

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thro different commands like offset, extrusion, and opetarions in GH like turning curves into surfaces and Beep

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break down into layers for laser cut

step 2: 3D print mold

On this first model, i didn't managed to accomplished the wall for the whole in the middle, so printed like this to then glue a piece of methacrylate for the hole:

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cura settings_laser cut mold: BASE 1

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cura settings_laser cut mold: TOP 1

Afterwards i managed to sport a different stl that CURA did read with the wall:

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cura settings_laser cut mold : BASE 2

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cura settings_laser cut mold : TOP 2

step 2b: laser cut mold

material: methacrylate 3mm
speed: 30
max power:72
min power:68

Then i glued this pieces layered one on top of each other and let it dry for 24h

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methacrylate mold

Step 3 : silicone

step 3.1: mix

We start by making silicone, around 250gr total should be enough for my molds, but i did it in parts, and with 2 different suppliers, as we run out of the first one. Which turned out good thing to test 2 different hardeness of silicone. We mix with 1x1 proportions.

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silicone

step 3.2: vacuum air

Take the air out on a vacuum air machine, make sure to use a plastic cup, vacuum until bubbles stop coming up.

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air vacuum

step 3.3: pour and dry 24h

Pour on the molds carefully, from a distance and with a thin thread of quantity dripping

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pour and dry

step 3.4: glue

Take your pieces out of the molds and glue the base and top parts with more silicone, use a thin brush. You can put some cabe or plastic tube to secure the air pathway.

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glue both halfs together with more silicone

3D Models

MOLD:

Result

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Fabrication files

File: LASER CUT MOLD


  1. MOLD: