VoidCrawler – Jason

The main objective of this project was to create an alien creature that embodied the theme of “Void” through peculiar movement and anatomy. I wanted to offer people an experience of encountering a foreign, alien organism that blurred the lines between lifelike and lifeless. The project utilized silicone to emulate fleshy appendages and motion, while making use of rigid material to create a protective shell.

Rnav – Inbar

My objective was to recreate Whitesides’ soft robot successfully, in order to then create another version of this robot that is scaled up to the dimensions of my pet rabbit. The purpose of the scaled-up version of the robot is to be feathered in one scene of my documentary project, which premise is centered around my hopeless attempts to restore the lost libido of a castrated pet. The design of my soft robot has only one variation from the original one – another round chamber that will be filled with a smell-induing liquid, for the purpose of drawing my rabbit to it. Thus, my objective was not to change the original design of the soft robot, but rather to utilize its aesthetics and the connotations of its materials to then showcase it in the context of my video project. The current title of my project is “Rnav”, which is a misuse of English letters that resolve in what sounds like the Hebrew word “Rabbit”.

Creative Design Opportunities

Jason

The use of soft silicone material allowed me to design and fabricate appendages that mimicked the texture of slimy and shiny creatures. Additionally, the silicone’s behavior when actuated created a slow and steady motion that imitated how animals get up from rest.

The versatility of the silicon also allowed modifications to be made during fabrication. Although not an intentional design choice, the use of the fabric within the clear silicone appendages created an interesting visual effect that resembled that of jellyfish. Furthermore, the usage of dyes within the silicone parts allowed for more creative freedom by creating really dark parts that match the theme of Void.

Beyond the silicone molds, the use of rigid parts through 3D printing incorporated some mechanics within the design. I was able to design a central unit where multiple appendages could be attached to create an n-legged creature. Similarly, I was able to use color with this material as well, specifically black, to produce a shiny and hard product that perfectly resembled a hard outer shell of an organism.

Inbar

The design process of Whitesides’ soft robot required me to learn several new skills: silicone rubber casting and bonding, parametric design using SolidWorks, and 3D printing. This is the first time that I’ve experimented with either of these skills, and the intense engagement with them during the course has led me to acquire enough knowledge so that I can continue to use them in my future projects. I find this very gratifying since silicone rubber and mold making is a scope in sculpture that I have always wanted to experiment with but never did because I felt I lacked the needed abilities and/or knowledge.

Silicone is an inspiring material that is fascinating to work with because of its skin-like qualities, and the different signifiers it can evoke in different contexts: body implants, props, sex toys, etc. However, the design and manufacturing process with silicone needs to be very precise and well-planned, especially when trying to mimic an existing robot from a scientific paper that does not include instructions or exact dimensions of each part. Such a slow and precise work process is very different from the creative processes to which I am accustomed in my artistic practice, and I believe this is the reason I had to go through a few failed fabrication attempts until I became accustomed to the orderly work process.

Outcomes

Jason

The final outcomes of the project were a fully assembled Void Crawler, albeit with only two functioning appendages. The sequence developed for the Void Crawler consisted of a basic rising up motion followed by actuation for just one appendage at a time.

The greatest success of this project was the design of the soft silicone appendages and the use of fabric during fabrication. The initial design choice of making the appendage a stretched-out hexagon was arbitrary but later showed interesting behavior as the chamber design was modified. The varying length of the thin chambers from end to end proved to create a desired “joint-like” actuation. Although this was assumed to be a result of the chamber pattern, there was no formal test to validate this claim. Upon additional research, a fabric embedding technique was found. It was implemented and provided a more consistent and circular curvature. Although some papers mentioned specific materials, regular and thin fabric performed really well.

One of the greatest failures within the project was bonding. Although in the end I managed to have two fully operational appendages, the bonding process proved to be too inconsistent to guarantee full bonding every time. There were several attempts to fix this issue. The latest solution with mixed results consisted of changing the shape of the tube port to square to allow slicing of a thin base layer. A full thin layer would be spread over the intricate top mold and then bonded with the thin bottom layer.

The current state of the project is very much a prototype. There are many ways this project can be improved upon. One of the key areas for improvement would be with the bonding. The research papers used in this project mentioned the use of “bonding surfaces” to ensure proper bonding. The current molds could be modified to include a new bond design that would incorporate this idea. Additionally, the lengths of each chamber and distance can be modified to see if there are more interesting movements that can come from the hexagonal shape. An idea mentioned early on in this project was the incorporation of an additional chamber within the center unit to initiate a vital organ, such as a brain. This idea can be further developed in the next iteration of this project.

Inbar

During the design process, Jason encountered a post online that documented a similar studential attempt to recreate Whitesides’ soft robot. During their fabrication process, these students decided to slightly change the robot’s design in order to allow for easier fabrication and bonding (they expanded the width of the inner chambers and also expanded the distance between the chambers). After several design attempts, I’ve decided to follow the same path and tried to recreate their design rather than the original Whitesides one.

My final soft robot bonded successfully except for one small slit in the bonding area, which I detached through a bubble test and resolved using epoxy glue. It was also pretty easy to understand and recreate the choreography that is needed to create crawling locomotion using the movement code – I followed the rhythm from a documentation video the previously mentioned students uploaded to that post. All five parts of my robot inflated successfully and the robot seemed to crawl forward through two consecutive loops of movement – until I pressed one of the legs and it exploded (as can be seen in my documentation video). Two more legs ended up exploding later in the showcase event, which perhaps means we used too-high air pressure. However, I do perceive this as a positive result, since the documentation video indicates that during the two movement loops that the robot completed before the first leg exploded, it did manage to move forward.

In the next few months, I plan to attempt to create a scaled-up version of this robot, and then use it while filming the scene I’m planning for my documentary project. I’m planning to scale up the same final design and stick to the same silicone casting protocol but will have to create the molds differently, due to the size limit of 3D printers. As a first step, I will try to fabricate one large-scale mold using wood and laser cutting. Another future step would be to identify and achieve the correct liquid to use within the added camber I added to the design, which might need to be the urine of a different rabbit or other substance that contains the appropriate pheromones.

Documentation video

Jason

Inbar

Citations

Jason

The project was almost entirely original, mainly drawing on ideas regarding fabrication and application found within many academic papers on the topic of soft robotics. One influential paper that helped in understanding the design and fabrication process, however, was the Whitesides paper on an untethered soft robot design. This paper provided more context for fabrication problems and solutions. Additionally, the paper on this starfish robot provided the inspiration for a central unit to attach all appendages.

Tolley, Michael T., Robert F. Shepherd, Bobak Mosadegh, Kevin C. Galloway, Michael Wehner, Michael Karpelson, Robert J. Wood, and George M. Whitesides. “A Resilient, Untethered Soft Robot.” Soft Robotics 1, no. 3 (September 2014): 213–23. https://doi.org/10.1089/soro.2014.0008.

Zou, JiaKang, MengKe Yang, and GuoQing Jin. “A Five-Way Directional Soft Valve with a Case Study: A Starfish like Soft Robot.” In 2020 5th International Conference on Automation, Control and Robotics Engineering (CACRE), 130–34, 2020. https://doi.org/10.1109/CACRE50138.2020.9230177.

Inbar

Hao, Bohan, “Soft-robot Design and Fabrication,” cargo collective, May 2013, https://cargocollective.com/bohanh/Soft-robot-Design-and-Fabrication.

Shepherd, Robert F., et al. “Multigait soft robot.” Proceedings of the national academy of sciences 108.51, 2011, https://doi.org/10.1073/pnas.1116564108‏

Technical Documentation

Inbar – CAD

Group Member Contributions

Jason:

• Updating code to work with the project specifications
• Testing thick chamber designs
• Bonding/Slicing technique

Inbar:

• Locomotion
• Testing thin chamber design

The latest iteration of the Void Crawler has seen changes in its air channel geometry along with a new slicing location. Although these changes may seem minimal, they seemed to greatly improve both the fabrication process and performance.

From this test, it seems that the flat base helped in ensuring a good bond between both parts compared to the previous chamber-to-chamber contact. Although this part did fail, its failure was contained to a single point rather than a separation of chambers. Once again, embedding the fabric within the base part allowed for more curvature. Its movement is exactly what I am looking for in bringing the Void Crawler to life. With the video, it seems it can easily and securely interact with the centerpiece. I propose for the next test to update the centerpiece to have four ports and test locomotion.

The centerpiece has been updated to include four ports and a locking mechanism. The next steps are to fully assemble the VoidCrawler and practice locomotion with the pneumatic system.

Inbar’s Update

After the previous attempt to create the entire robot, which failed mainly due to difficulty in bonding, I changed the structure and cut plan of the molds so that the tube opening is now on the top face of the robot, and all internal texture is only at the top part so that the bottom part is a thin and smooth layer (which also contain the fabric). That way, the bonding is done by coating the entire bottom part with a thin layer of silicone and then placing and aligning the top part on top.

The bonding in the current version was indeed successful – a bubble test in water showed only one bonding malfunction at the edge of one of the legs – which was easy to solve with epoxy glue.

The airway cavity of one of the distant legs was blocked during bonding, but it was easy to fix by punching the blockage with a needle.

All five parts of the robot show a nice curvature while inflating, as long as I apply pressure to close the opening around the inflating tube. I made an attempt to set the tube in one of the openings with two layers of epoxy glue and it seemed to work – as you can see at min 2:30 of the video.

The next two steps:

1. To program the choreography of the air pressure system in order to produce crawling locomotion.

2. In case I achieve crawling locomotion that is satisfying enough, I would like to plan the fabrication of a scaled-up version, that should be around 70 cm long (27.5 inches), for the purpose of filming the scene with my pet bunny.

Documentation video:

Jason: This latest iteration corrected many of the mistakes made during the previous iteration. The most drastic design change was the chamber designs. It retained the Whiteside’s thin chambers but with a two-millimeter gap between surfaces. The biggest change was in varying distances between the edge and angle with the chambers. This change was made to test how the varying lengths affect the actuation. Overall, the combination of the fabric and chamber geometry led to actuation with greater concavity. Unfortunately, one section did not bond well and caused a tear. However, this can be remedied by improving the process. The next steps are to create a central body unit and attempt a full body mold.

https://drive.google.com/drive/folders/1fxSou0ma5k9XlpAtVw6NzxqrmjjDLu85?usp=sharing

https://drive.google.com/file/d/1SHFikJNq-ciDY7pXxd8cyCk1bjLx0iWS/view?usp=sharing

Images

Changes Made:

• Scaled up design from previous iteration by increasing width to 50mm and length to 100mm
• Reduced height on top of chambers to allow for more stretching (1mm thickness)
• Increased number of chambers
• Made air passage slightly bigger to account for bigger size
• After using 0045 silicone with previous iteration, decided to use material again due to its softness

Volume: 10.7 cubic centimeters

https://drive.google.com/file/d/16njlrh3DOr1OjIXs-bdDl8iiZmfwqxlP/view?usp=sharing

Images

The second iteration of the design scaled down the size and thickness of the original part. Another significant change was the change in the silicone material. Instead of using the 00-31, this iteration utilized the 00-45 silicone. The demolding process was a lot more seamless with this part, probably due to a combination of both size and material. More importantly, this design was successful in performing some sort of actuation. Due to the large chambers in the middle, upon the initial tests, the part bent in the middle quickly. Overall, the part seemed to function like a joint.

https://drive.google.com/file/d/1h36vq2eovtEZKEU_dhWe0dBuCbC7CYab/view?usp=sharing

Images

This first iteration used the 00-31 silicone which was stiff. This property was amplified by the thickness of my design. Although the part did not inflate fully, it did provide valuable experience in the design and fabrication of soft robot parts.

The next two experiments will focus on testing locomotion with three and four appendages while implementing some of the movement patterns outlined in the attached paper.

Essential Material/Equipment

• Black dye
• Several of the mentioned materials in last class

Joint Bibliography

The main focus of this paper is on an untethered, battery-operated soft robot that can operate in several conditions. However, we focused on the specific details outlined about the actuation on different “appendages” to create two kinds of gaits: undulating and ambulating. The steps outlined in the paper would allow us to replicate those movement patterns with our own models.

Tolley, Michael T., Robert F. Shepherd, Bobak Mosadegh, Kevin C. Galloway, Michael Wehner, Michael Karpelson, Robert J. Wood, and George M. Whitesides. “A Resilient, Untethered Soft Robot.” Soft Robotics 1, no. 3 (September 2014): 213–23. https://doi.org/10.1089/soro.2014.0008.

The Interstellar Being project will introduce humans to a never-before-seen alien from beyond our solar system. The monochromatic color scheme of the creature is an extension of its void origins. The creature’s unique anatomy, size, and movement will serve as humanity’s first contact with another organism, that is if they choose to do so…

Creative Requirements

The Interstellar Being project would consist of a central body (6″x3″x2″) with three appendages (6″x1″x1″). The entire project would be dyed black with a shiny finish. The appendages should retain the smooth, soft texture of the silicone while the main body will have plates added to resemble armor. The plates will have a different shade of black to emphasize ruggedness and wear. The essential movements would be getting up and a defensive stance. The getting up movement would be slow and steady. As a direct contrast, the defensive stance will be fast and responsive. The minimum number of control channels required is four: one for each appendage and one for the body. The overall design language is the use of unnatural color and anatomy to incite curiosity and interactions. The specific insight that led to this revision was that tethered movement was still interesting and that touch interaction would be made more interesting with different textures.

Critical Path

The simplest version of the system that can achieve the outlined goals would be a variation of the Whitesides Team’s starfish soft robot. Instead of having four appendages, a mold would be modified to only have three. This step may prove to be difficult, so an alternate plan would be to use the existing four-legged mold. The components of the overall system would consist of just silicone and tubing for actuation and movement. The main source would be pneumatic. The addition of wooden “scales” for the armor would be necessary in addition to the soft materials. If a more unified structure is chosen, such as the one outlined in the starfish robot, the fabrication of the central module with three valves would be the most difficult to fabricate. This also becomes the most difficult component to design, however, the references provided in the paper might make the process easier.

Proof of Concept

The main goal of the first experiment would be to create a simple system with appendages to get familiar with the constraints on movement. This goal would be achieved by finding and utilizing a model that is similar to the Whiteside Team’s and using the silicone casting methods discussed so far in class. This initial step would also answer the question about actuation. The methods researched and discussed involve pneumatic systems. It seems that these mainly rely on specialized machinery which may not be available but more accessible methods could be identified.

Resources

https://cargocollective.com/bohanh/Soft-robot-Design-and-Fabrication

Zhang, Jiawei, Andrew Jackson, Nathan Mentzer, and Rebecca Kramer. “A Modular, Reconfigurable Mold for a Soft Robotic Gripper Design Activity.” Frontiers in Robotics and AI 4 (2017). https://www.frontiersin.org/article/10.3389/frobt.2017.00046.

Zou, JiaKang, MengKe Yang, and GuoQing Jin. “A Five-Way Directional Soft Valve with a Case Study: A Starfish like Soft Robot.” In 2020 5th International Conference on Automation, Control and Robotics Engineering (CACRE), 130–34, 2020. https://doi.org/10.1109/CACRE50138.2020.9230177.

Art/Design

Technical Research Paper

Jones, T.J., Jambon-Puillet, E., Marthelot, J. et al. Bubble casting soft robotics. Nature 599, 229–233 (2021). https://doi.org/10.1038/s41586-021-04029-6

Zou, JiaKang, MengKe Yang, and GuoQing Jin. “A Five-Way Directional Soft Valve with a Case Study: A Starfish like Soft Robot.” In 2020 5th International Conference on Automation, Control and Robotics Engineering (CACRE), 130–34, 2020. https://doi.org/10.1109/CACRE50138.2020.9230177.

https://www.nasa.gov/feature/langley/beyond-the-metal-investigating-soft-robots-at-nasa-langley

https://www.guggenheim-bilbao.eus/en/the-collection/works/maman

Artist Expression/Intent

Initial impressions were intimidating, unnatural, and invasive. However, after reading more about the artist’s life and intent, it shifted more towards protection and creation. The inclusion of the eggs in the sculpture introduces a maternal element that is made more obvious with its name. Overall, the artist seems to display the grand but intimidating natural force of motherhood.

Exploration with Soft Robotics

I believe the main benefit this work can receive from soft robotics is movement. In its current state, the sculpture is still and only has its fixed characteristics to express itself. With the introduction of leg movement, the sculpture could further enhance its message by reacting to touch or simply “be on guard” by moving constantly. One thing I believe would not work as well is its size. The original work is very big and that helps grab attention to itself and its intricate details. Those features may be lost when required to scale down for soft robotics.

Applications of Soft Robotics

I believe a critical part would be to centralize the location of actuation of its several appendages. An article found in an earlier exercise would serve as the best solution. The soft valve shown in the paper is shown being used in a starfish soft robot. Up to four out of five appendages were able to be controlled all within one central unit. I believe the methods presented in the paper could be applied to a new iteration of the artistic work. The introduction of movement through soft valves and actuation would add life to the original work by mimicking natural instincts.

Zou, JiaKang, MengKe Yang, and GuoQing Jin. “A Five-Way Directional Soft Valve with a Case Study: A Starfish like Soft Robot.” In 2020 5th International Conference on Automation, Control and Robotics Engineering (CACRE), 130–34, 2020. https://doi.org/10.1109/CACRE50138.2020.9230177.