12. Soft robotics

Research

Bubble Bracelet Credit: Machteld Zee

Ever wondered why robots have got be so big and bulky, and cloinky from all the metal? This week we're flipping the script. Instead of these tough and rigid bots, let's think about making robots that are soft and cuddly. You know, ones that won't accidentally hit you in the head and hurt you. Maybe even ones you can wear, like a cool inflatable bubble bracelet!

So, here's the plan: we're looking into making soft robots using a silicone mold.

Soft robotics is a subfield of robotics that focuses on the design, construction, and application of robots using soft and flexible materials. Unlike traditional rigid robots, which are typically composed of metals and hard plastics, soft robots are made from materials that can deform and adapt to their surroundings. This enables them to interact with their environment in a more flexible and versatile manner.

Key characteristics of soft robotics include:

1. Soft materials: Soft robots are constructed from materials such as elastomers, polymers, and other compliant substances. These materials allow the robot to deform and stretch, enabling a wide range of motions and interactions.

2. Flexibility and adaptability: Soft robots can deform and change shape to navigate complex and dynamic environments. This makes them well-suited for tasks that require interaction with delicate objects or environments where rigid robots might struggle.

3. Safe interaction: The compliant nature of soft robots makes them safer to interact with humans and delicate objects. This quality is particularly useful in applications such as healthcare, where robots may assist with medical procedures or rehabilitation exercises.

4. Bio-inspired design: Soft robotics often draws inspiration from biology, mimicking the flexibility and adaptability of natural organisms. This can lead to designs that are well-suited for specific tasks, such as crawling, gripping, or squeezing through tight spaces.

5. Variable stiffness: Soft robots can have variable stiffness, meaning that their rigidity can be adjusted depending on the task at hand. This feature allows for a greater range of applications, from delicate manipulation to more robust actions.

Applications of soft robotics span various fields, including:

• Medical robotics: Soft robots can be used for minimally invasive surgery, rehabilitation, and prosthetics, taking advantage of their safe and adaptable nature.

• Search and rescue: The flexibility of soft robots makes them suitable for navigating complex and cluttered environments, such as disaster sites, where traditional rigid robots may face challenges.

• Human-robot interaction: Soft robots are well-suited for applications where close interaction with humans is necessary, such as in assistive devices or wearable robotics.

• Object manipulation: The compliant nature of soft robots allows them to manipulate and handle objects with different shapes and sizes more effectively than rigid robots.

TPU and vinyl - mimicking human muscles

Because soft robotics often mimic human muscles, I experimented with muscle like shapes:

You can see how long and narrow contract better - and would make better grippers.

What you need for this:

A heat press (15 seconds on 140 degrees celsius)

Baking paper

Scissors

Vinyl sheets

For the TPU one you exchange the heat press for a lamination machine (I ran it three times through)

Here's what you do:

Think of a shape you want to make

Cut that shape in baking paper - and leave a 4mm gap with baking paper for a straw.

Cover the baking paper with vinyl sheets, front and back and wrap this in baking paper, front and back.

Put in the heat press (vinyl) or the laminator (TPU).

TPU is softer and more flexible than vinyl sheets.

Soft Robotic Gripper

This is an experiment about designing a soft robotics gripper. It involves integrating flexible and compliant materials to create a versatile and gentle yet strong grasping mechanism. The molds themselves are made with a laser cutter with acrylic sheets. The gripper is made from pouring Ecoplex silicone.

SOFT ROBOTICS from Jiawen Gong on Vimeo.

References & Inspiration

For my own silicon mold I drew inspiration from one of the Fabricademy's alumni, Montserrat Ciges.

Credit for the images above: Montserrat Ciges

Tools & Supplies

Rhino

Lasercutter/Lightburn

Ecoplex (70ml Part A and 70ml Part B for pouring the mold, 5ml A and 5ml B for glueing)

Acrylic plates

Air pump machine

Process and workflow for the Bubble Bracelet

Test with one bubble

First I tested the idea of the bubble.

I poured a bit of silicone in two plastic cups, let it dry for 4 hours, glued the two sides together with a bit of silicone and put in a straw for the airpath.

Now I'm ready for the bracelet. I was inspired by Bauhaus colours and shapes, as well as Montserrat Ciges' designs.

Design a mold

Design a mold in Rhino. It should consist of two pieces, and well thought through in terms of air channels.

(Lightburn settings: 25 speed, 90 power max, 15 power min)

Silicon and testing

Pour ecoflex in. Tap the container for two minutes to get rid of bubbles.

Wait for at least 3,5 hours. Then glue the two parts together, with a bit of silicon.

Wait for another 3 hours.

As you can see in the two clips above, the bubbles do not inflate evenly. Inflating it with the airpath on the upperside, only the first bubble blew up, and really big, too, almost on the verge of exploding. Then I decided to close that airpath and make a hole in the middle. It went better, nut still not even. I have yet to figure out how to fix that.

Fabrication file

File for the Bubble Bracelet