8. Soft robotics

Research

SENSE, THINK AND ACT

Soft robotics is a subfield of robotics that builds mechanical systems out of flexible, compliant deformable materials like silicone, rubber and gels. Often inspired by biological structures found in nature, soft robots can possess a limitless number of joints, and are typically made out of elastic, deformable materials like silicone rubber or gels that can stretch, bend, squeeze or twist without losing shape.

Soft robotics focuses on making robots from pliable materials that allow them to bend and return to their original shapes. These robots are often biocompatible and can adapt to complex environments — including human interaction — with minimal damage or risk. They’re actuated in unique ways — from air or fluid pressurization to electrical signals and heat stimuli. These actuation systems control how the soft bot moves, determining its range of motion and how it interacts with its surroundings.

According to Carmel Majidi, professor of mechanical engineering at Carnegie Melton University, the concept of using rubbery materials, balloons and other soft structures in robotics has been around for over half a century and it is not new, nor the emerging technology. Soft robots are highly adaptable to dynamic scenarios and can interact safely with humans or delicate objects. Instead of using rigid motors, soft robots use alternative actuation methods, like inflatable chambers, heat or magnets, to create movement.

Key characteristics

•   Material composition: Soft robots are constructed from soft materials such as elastomers, gels, and fluids, rather than the hard metals and plastics used in traditional robots.
•   Bio-inspiration: Their design is often based on biological systems, mimicking the locomotion and functionality of animals like earthworms, octopuses, and snakes.
•   Adaptive and safe: The softness and flexibility allow them to absorb impacts and adapt to their environment, making them safer for tasks that involve close contact with humans or delicate objects.
•   Soft actuators: They are often driven by "artificial muscles" powered by mechanisms like pneumatic or hydraulic systems, which inflate or deflate to create movement.

How they are made:

Many soft robots are fabricated using additive manufacturing, or 3D printing, which allows for complex, programmable shapes and the integration of fluidic networks. This manufacturing method can create actuators with locally defined mechanical properties and bio-inspired designs, leading to a wide range of motions such as bending, twisting, and grabbing.

Aplications:

Their dexterity is more closely matched to the properties and capabilities of soft human tissue or soft biological organisms, so they are used in different fields like:

Healthcare: Soft robots are flexible and biocompatible, they can interact with the human body in many ways like navigating through the human body with minimal tissue damage, in pill form, as bionic prosthetics and physical therapy.

Agriculture: Soft robotics, particularly soft grippers, allow for delicate handling and harvesting of fruits and vegetables without causing damage. They are highly adaptable.

Manufacturing: Soft robots offer a gentler touch when it comes to moving products in warehouses and on factory assembly lines. They can handle fragile and irregularly shaped objects, reducing the risk of damage compared to hard robots.

Ocean and Space Exploration: Soft robots can withstand extreme pressure and temperature variations in harsh conditions. Their soft, deformable bodies enable them to navigate challenging terrains, such as underwater crevices or the surface of distant planets, while safely interacting with delicate ecosystems or equipment.

Search and Rescue: Soft robots have flexible and adaptable bodies that allow them to navigate through tight spaces and tough terrain. They can safely interact under harsh conditions and even provide assistance to trapped individuals by squeezing through confined areas during emergency rescues.

Fashion: Soft robotics is being integrated into fashion to create smart, adaptive clothing that can change its properties and provide new functionalities. Potential applications include temperature-regulating garments, wearable health monitoring and support devices, and garments that change shape or style on demand. This is achieved by embedding soft robotic elements into textiles to create smart fabrics that are soft, flexible, and can interact with the wearer and the environment.

Kris Dorsey is an associate professor in the departments of Electrical and Computer Engineering and Physical Therapy, Movement, and Rehabilitation Sciences explores the potential applications of this revolutionary technology. She showcases how innovative components like 3D-printed fabric, soft sensors, and air-powered motors could shape the future of what we wear.

Applications for wearable apparel:

•   Thermal management: Smart clothing can automatically adjust its breathability and insulation based on the wearer's body temperature and the ambient climate. This can involve inflatable air gaps that inflate in the cold for more insulation and deflate in the heat for better breathability.
•   Adaptive fit and shape-changing: Garments can subtly change their style or fit throughout the day, for instance, adjusting from a professional look to an evening style.
•   Health and mobility support: Soft robotic exosuits and gloves can provide muscle support or assist with hand movements. In the future, this technology could also help those with mobility issues by assisting with movement.
•   Haptic feedback and sensing: Fabrics can be embedded with sensors to monitor the wearer's health or provide haptic feedback. For example, a shirt could offer a back rub if it senses the wearer is stressed.
•   Performance enhancement: Wearable devices can improve performance in various fields, such as activewear for athletes or functional gear for outdoor workers and firefighters. 
•   Knit soft actuators: A smart textile-composite actuator developed by researchers uses a shape-memory alloy wire and knitting techniques to create a fabric that can be programmed to bend and curl.

Textiles are one of the most common and versatile materials for soft robotics, as they can provide comfort, breathability, durability, and functionality. Soft robotics can help physically challenged people with mobility, therapy and daily activities.

Smart e-textiles can integrate actuators and sensors into the fabric to monitor the wearer’s posture, motion, vital signs and other health-related parameters, adapt to the user’s body shape, size and preferences, as well as to the external conditions such as temperature, humidity and light.

Manufacturing and Design

Soft robotics can be actuated through various methods, including thermal actuation, which uses electrically controlled phase changes in embedded materials. The integration of soft robotics requires new manufacturing techniques, including advanced sewing (sewbots) and the creation of smart textiles with integrated sensors and actuators. Fabric-based sensors are particularly well-suited for wearable applications because they are flexible, safe for skin contact, and can be made from fibers and yarns.

Automated manufacturing of clothing is difficult because of the soft and ductile nature of fabrics, but soft robotic grippers can solve this challenge.

•   Soft grippers for textile handling 
•   Soft-touch grippers: Companies are developing soft grippers with a gentle touch that can precisely grab, handle, and stack delicate fabrics.

Automated dressing assistance for individuals with limited mobility, soft robotics offers a safer and more efficient alternative to rigid manipulators for dressing assistance.

•   Self-Wearing Adaptive Garment (SWAG): This system uses an unfurling and growth mechanism to deploy a garment onto a user's body, minimizing skin-garment friction.

Programmable mannequins using soft robotic technology can allow mannequins to deform and simulate different shapes, assisting in the design and fitting process.

•   Shape-deforming mannequins: The University of Manchester has developed a soft robotic mannequin with programmable shape deformation to assist with sustainable garment fabrication.

The integration of soft robotics into fashion still faces several challenges.

•   Cost: Many advanced materials like shape-memory polymers are expensive, limiting widespread adoption and accessibility.
•   Durability and washability: Ensuring that advanced, functional fibers can withstand repeated washing and wear is an ongoing area of development.
•   Sustainability: The field needs to address the long-term sustainability of materials and their impact on the environment.
•   Data and privacy: Ethical considerations related to data collection from smart wearables need to be addressed as these technologies advance.

References & Inspiration

Fashion and artistic expression come together in wearable art. It transcends clothing, transforming clothing into means of expressing individuality and creativity.

After hearing the lecture from Lily Chambers and Adriana Cabrera, I was fascinated and looking forward to starting the research and developing my own rudimentary soft robotics.

For Fab Academy, integrating soft robotics offers exciting opportunities to explore innovative materials and digital fabrication techniques, such as 3D printing, laser cutting, and molding, to create functional and customizable robotic solutions. Through hands-on experimentation, this project will aim to highlight how soft robotics can revolutionize automation and human-robot interactions.

There are two designers and artist that I follow. Ones is Ying Gao, She is a fashion designer based in Montreal and in her designs, she combines fashion design, product design and media design is back with new robotic clothing, this time drawing influence from the metaverse and NFTs. Her latest outfits use silicone, glass, and precious metals to create a polymorphic material that mimics the effects of virtual clothes, giving the impression that they are pulsing and twisting like floral beings. You can follow her here: Ying Gao

The other artist is Philip Beesley. He is a multidisciplinary artist, designer, and university professor. A practitioner of sculpture test beds and digital media art, his work is cited for his contributions to the field of responsive and interactive systems.

You can follow him here: Philip Beesley

TOOLS

1.  Silicone,
2.  Catalizer
3.  Scissors, 
4.  Iron
5.  Paper, 
6.  Baking paper, 
7.  Plastic bags, 
8.  Tape, 
9.  Syringe,
10. Bicycle pump, 
11. Ballons, 
12. Straw, 
13. 3D printer, 
14. Rhino
15. Diluent

Testing

I began my journey looking for DIY videos to get to know soft robotics. I made some homemade soft robotics with plastic bags, tape and tried them Not all of them were a success. I had trouble regulating the temperature of the iron and sealing the straw, the syringe or the Bicycle pomp to the prototypes.

1st Swatch

I draw in a piece of baking paper a rectangle with cut-outs at the edges, placed it between two pieces of plastic, taped on the edges and after ironed. It worked but it did not inflate were the baking paper was, there were sides not ironed as needed, so when I blew into it, it inflated irregularly.

2nd Swatch

I cut a rectangle 27cm long and 4 cm width, then I folded it in smaller rectangles, made them holes and wrapped it in plastic, held it on one end and then inserted the straw and blow into it. It did work. It moves like a worm

3th Swatch

I simulated a compound leave as a palmery or pinnately and I saw it on the plastic, cut the extra plastic and introduced a long thin ballon. Then with a bicycle pump I inflated the balloon and it work really nice, it bends inwards.

Fourth Swatch

I drew three rhomboids and sew thenm to a rectangle made of two layers of plastic. Later I covered it again with plastic and introduced the staw in the open cavity to try it out and see if it worked. For my surprise it did work!

Gripper Prototyping Process

After having made the first ever soft robotics swatches I decided to start modeling my soft robotics with Rhino. I began looking for soft robotic examples and searched for other alumni work. I liked the work from:

Sakia Helinka

Pauilina Serra

Also, on the Mattermost channel they recommended to look through the Soft Robotics Toolkit page and found different models suitable for the activity, getting inspired and think of what to do. I thought of making a gripper with three legs simulating the birds’ feet and the camaleon.

Modeling it turned out to be difficult due to my knowledge of it. I got really confused by having to think of it in a negative way to get the soft robotics correctly to inflate by exerting air pressure in it. I struggled, so I looked for some existing models and found tones of them. I recommend these two pages:

Yeggi

Thigiverse

I found lots of examples of soft pneumatic actuators and a tutorial witch I used to guide me through the construction of my silicone gripper. I started trying to doit exactly as the example, and as well, my tutor from the Fablab, Jonathan León helped me do it correctly.

How to build your own Soft Robot

I Had the opportunity to print them on different 3D printers, so the process was faster. I printed them in different colors to identify one another and not get confused. It took 1 hour and a half to get them ready.

Gripper.png

Once my 3D molds were redy I gather all the materials needed for the silicone and put the recipe near by to follow it with detail, because it was the first time doing it.

Recipe:

1.  80 grs Silicone
2.  80 grs Diluent
3.  50 drops of catalizer

You put all the ingredients on the plastic cup over the scale to measure. Then stir vigorously until it gets smooth and pour it down into the 3D molds. Be careful not to generate bubbles and if they do, just break them softly. Leave them dry overnight for a better result.

Meanwhile the silicone dry I tried again to make some soft robotics with plastic again. This time I put more attention on the iron temperature and the display of the plastic for me to do it more rapidly and efficiently.

I tried these three swatches but the leaf did not work because when I blew in some places broke and the air came out.

1

2

Testing the Gripper

First, I unmolded the two gripper pieces and added them together with more silicone and waited a long time.

 It looks nice and it’s ready to try it.

I have been having trouble with mi soft robotics, I can 't get it to inflate and neither inflate it. The tophandle needed to assemble the hose is getting loose so I made a little more silicone solution to try to glue it again.

Sadly my gripper did not dry so I could not test it.

Testing another soft robotics

When I did the mixture of silicone por the 3D molds I made more than needed so I used it on other silicone mold I already had and I also dismolded it.

Honestly I did not know if it was going to work or not, but it was worthy to try.

I was amazed by the result, it looked like a small heart beating. It would be nce to se if it can be programmed in Arduino.