8. Soft robotics¶
References & Inspiration¶
This week has been an exciting and inspiring journey into the world of soft robotics. The work in soft robotics takes a very particular approach to the combination of soft materials (such as silicones, elastomers, and hydrogels) with traditional hardware, opening up new possibilities in design and function.
One of the most intriguing aspects of soft robotics is the departure from rigid, traditional robot design. Instead of
relying on hard materials and complex mechanical systems, soft robots are built to deform and adapt, much like biological organisms. This flexibility allows them to perform tasks that traditional robots cannot.
During our lecture we had the pleasure to see the process of creating this very interesting piece.
Working with soft robotics is not just about learning new technologies, but also exploring how to merge two distinct disciplines —soft materials and rigid hardware— in ways that expand the possibilities of both fields. This cross-disciplinary approach is particularly inspiring, as it can be applied in different industries such as fashion design.
Inspiring Fashion
Iris van Herpen’s designs often utilize highly flexible, sculptural, and intricate forms, qualities that align closely with the principles of soft robotics. Iris Van Herpen’s work often involves 3D printing, smart materials, and interactive textiles, which echo the adaptable, bio-inspired nature of soft robots. The fabrics and materials she uses are designed to move and deform in ways that mirror the soft and flexible nature of biological organisms or robotic systems.
For example, in her 2019 collection "Hypnosis", Van Herpen worked with fabrics that move in a way that mimics natural processes. The garments seemed to evolve and shift, almost like living organisms, similar to how soft robots change shape and adapt to their surroundings.
Tools¶
Understanding soft robotics¶
Soft robots are robots made from flexible, bendable materials, rather than rigid metal or plastic parts. This allows them to move in a much more fluid, natural way, similar to how animals or even humans move. They can stretch, squish, and bend, which makes them ideal for tasks that need flexibility and a gentle touch.
How do they work?¶
Inflatable soft robots use air or liquid to make them move. They work like a balloon inflates and changes shape when you blow air into it. The same idea is used in soft robots, but instead of just a balloon, they have special parts called inflatable actuators that control how the robot moves.
For our soft robot to work we need to decode how it works.
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Inflatable Chambers: These are soft, flexible parts inside the robot. They look like small balloons or tubes. When you blow air into them (using a pump or pressurized air), they inflate and get bigger. This change in size makes the robot move or change shape.
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Air Pressure Makes Movement: When the inflatable parts fill with air, they push against the rest of the robot. This causes the robot to bend, stretch, or expand. For example, if you have an inflatable "arm" on a robot, inflating it might make the arm bend or reach out. By controlling how much air goes into different parts of the robot, you can make it move in lots of different ways.
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Flexible Materials: The inflatable parts are made from flexible materials (like rubber or silicone), so they can bend and stretch easily. This makes the robot lightweight.
What are they used for?¶
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In Medicine: Inflatable soft robots can be used in surgery, where they can bend and navigate inside the human body with very little risk of causing damage.
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For Gripping: This inflatables can handle fragile objects making them useful in fields like logistics, packaging, and food handling.
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In Exploration: Inflatable soft robots can squeeze into tight places, making them great for things like searching collapsed buildings or exploring narrow tunnels.
Creating simple forms¶
This week, we started with a simple yet exciting project: creating our very first inflatable. The idea was to design and build an inflatable structure from scratch, using basic materials like vinyl and parchment paper, and to explore how to inflate it and control its shape.
Designing the shape
The first step was designing the form for the inflatable. I used Rhinoceros (a 3D design software) to create an organic, smooth shape. Soft robots often have flowing, curving forms, so I wanted to capture that aesthetic in my design. I focused on making the lines smooth and continuous, to make sure the inflatable could expand and contract naturally when air was introduced.
Preparing the materials
Once the design was ready, I used a laser cutter to precisely cut the shape I had designed into parchment paper. The parchment paper was chosen because it’s light and flexible, and perfect for the inner layer that would hold the inflatable shape. After the parchment paper was ready, I cut the vinyl (which would be the outer layer of the inflatable) to match the design. Vinyl is durable, flexible, and able to hold air, making it an ideal material for the outer shell of the inflatable structure.
Material: Vinyl
CUT
Speed: 115
Min. power: 31
Max. power: 32
Material: Parchment paper
CUT
Speed: 115
Min. power: 24
Max. power: 25
Assembling the inflatable
To put everything together, I used a hot iron to bond the vinyl together. The heat sealed the vinyl to the edges, effectively trapping the parchemnt paper inside the vinyl layers. This created a sealed pocket that would hold air once inflated.
Inflating the structure
The final step was to test the inflatable. I used an air compressor to pump air into the structure. As the air filled the inflatable, it expanded into the shape I had designed, and the vinyl stretched and shifted in response, just like how soft robots expand when inflated.
Creating moving figures¶
After successfully creating my first simple inflatable, I was ready to step up the challenge and design a moving arm that could curl up. I used the same basic technique as before — combining vinyl and parchment paper — but this time the goal was to create a more complex structure that could respond to air pressure and move in a specific way.
Designing the Inflatable Arm
I started by designing the arm in Rhinoceros again, keeping the organic lines from my first inflatable. I used the same approach but took inspiration from other examples of inflatable soft robots, trying to incorporate a curled, flexible movement that I wanted to achieve. The goal was to create a structure where, once inflated, one part would curl up while the rest remained stable.
Trial and error
At first, things didn’t go as planned. I tried several designs, but none of them worked—either the arm didn’t curl properly, or it inflated in strange ways. It was frustrating, but I kept experimenting, adjusting the design with each new attempt.
After several failed attempts, I realized something crucial: for the inflatable arm to curl up correctly, one part of the structure shouldn’t inflate fully. Instead, I needed to leave a section of the inflatable uninflated to create a pressure differential. By not inflating part of the arm, the air pressure would push on one side, pulling the other part and making it curl.
Refining the design
Once I understood this concept, it became easier to tweak the design. I went back to the drawing board, using this new technique to guide my changes. I repeated some of my earlier designs, but this time, they worked much better. The arm began to curl as intended, though it still wasn’t perfect. After several iterations, I refined the design until I achieved the movement I wanted. The final inflatable arm worked as planned, it could curl up when inflated, just like I had imagined!
Filling it up¶
After getting the inflatable arm to work, I wanted to take things a step further and experiment with making the inflatables not only move, but also change color when inflated. The idea was to inject colored water into the inflatable, creating a visually dynamic effect as the air inflated the structure. However, things didn’t go as smoothly as I expected.
First Attempt with Colored Water
I started by filling the inflatable with colored water and then using the air compressor to pump air into it. My hope was that the colored water would move and shift inside the inflatable as it expanded, giving it a vibrant look. But as soon as I started pumping air, I realized that the water didn't move as I had expected. It stayed still inside the inflatable, while the air filled all the other empty spaces. This caused a messy outcome where the water just pooled in one part of the inflatable, and the rest of the structure inflated normally, making it visually inconsistent and not at all what I had envisioned.
Switching to Water with Alginate
After this failure, I thought about how to make the water behave differently inside the inflatable. I realized that if I used a thicker fluid, it might stay in place and move more predictably within the inflatable as it expanded. I decided to try using water mixed with alginate and glycerin, giving it more structure and making it less likely to just sit still.
When I tried this new mixture, it worked as expected! The thicker water with alginate was more stable inside the inflatable. As I pumped air into the structure, the fluid shifted and expanded more smoothly, creating the color-changing effect I was hoping for without making a mess. The dense fluid moved in response to the pressure, while staying contained in the sections I wanted it to.
The dense fluid allowed the inflatable to behave more predictably, and it also gave me the colorful, dynamic effect I wanted. The fluid moved within the inflatable in a much more controlled manner, adding a fun and visually appealing dimension to the project. It also helped me understand how fluid dynamics work inside inflatable structures and how to manipulate the properties of the fluid to achieve the desired effect.
Final project¶
Garment Design¶
For my final project, I wanted to bring together all the techniques and concepts I had learned throughout the week into a single, cohesive design. The goal was to create a garment that could combine the fluid dynamics, inflatable mechanisms, and organic forms I had experimented with, while also incorporating a dynamic visual effect. The result was a headpiece, a wearable design that would not only inflate but also create stunning visual and movement effects.
Document preparation¶
To begin, I used Rhinoceros to create the design of the headpiece. I wanted the piece to have organic shapes with flowing, curving lines. The design was inspired by natural forms, with elements that would move, inflate, and interact in dynamic ways. Rhinoceros was perfect for this, as it allowed me to create precise, 3D models with smooth, organic contours. I modeled the entire headpiece in Rhino, paying special attention to the placement of the inflatable chambers and the sections that would curl, like the two horns.
You can download here the Rhinoceros document!
Moulding¶
Once I had the design, I needed to make physical molds for the inflatable parts. These molds were essential for creating the final silicone pieces. Using my Rhino model, I created molded shapes that would form the structure of the headpiece when filled with air. I then transferred the designs into flat files for the laser cutter, which cut out the necessary components with high precision.
Laser cutting the molds
The next step was to use the laser cutter to cut the molds out of a material that would serve as the base for casting. I chose methacrylate for its ability to provide a sturdy, smooth surface. I carefully set up the files in the laser cutting software, making sure that the shapes were accurately scaled and aligned. After cutting, I had a set of molds that would be used to shape the silicone components of the headpiece.
Material: Methacrylate
Thickness: 3 mm
CUT
Speed: 30
Min. power: 68
Max. power: 72
Material: Methacrylate
Thickness: 5 mm
CUT
Speed: 15
Min. power: 70
Max. power: 74
Creating the silicone pieces
With the molds ready, I moved on to casting the silicone parts of the headpiece. Silicone was the perfect material for the job, it’s flexible, durable, and can be molded into the organic shapes I needed. I mixed the silicone and poured it into the molds, ensuring that the material filled the cavities completely. After the silicone cured, I had a set of inflatable silicone components, which would form the horns and other parts of the headpiece.
Results¶
The silicone pieces were now ready to be incorporated into the inflatable mechanism. I used the same technique I had learned in earlier experiments: water mixed with alginate to create a colored, gel-like fluid that would fill the inflatable sections. I injected the colored fluid into the silicone chambers, which would then be inflated using an air compressor. As the air filled the inflatable sections, the silicone expanded, and the color shifted within the material, creating a beautiful, dynamic effect.
The most exciting part of the design was the organic movement. I had designed the two horns to curl upward as air was pumped into the headpiece. By controlling the inflation and using the alginate fluid to add color, I was able to create a fading color effect while maintaining smooth, fluid movements. As the air pressure increased in one part of the structure, it pulled on the horns, making them curl up slowly, much like I had seen in my earlier inflatable experiments.
This project was a hands-on way to see how inflatable structures work in soft robotics. The most exciting part was watching the inflatable take shape and move in real time as it filled with air. It really gave me a sense of how pneumatic actuators can create movement and flexibility in soft robots. The organic design allowed the inflatable to adapt as it expanded, demonstrating how soft robotics can combine flexible materials with air pressure to create a dynamic, responsive system.
The whole process—from designing in Rhinoceros to using the laser cutter and silicone was a great introduction to how we can use technology and materials to create functional soft structures. It was amazing to see the concept come to life with just a few basic materials, and I can’t wait to experiment further with more complex designs and larger inflatables.