We were able to 3d print all of our final molds, including the expanded and contracted meshes with fine detail. These will be cast by 4/19, and ready to go for the final assembly.
We also finished our system design. Instead of computer control, we decided that direct interaction through a series of handles or rings would provide a more engaging experience for the users. The softness and springiness is intrinsic to our designs, so allowing people to get hands on with it makes more sense. The ability to also distort the meshes at different angles and forces is an advantage of the direct handling. The meshes will then be placed in clear acrylic frames, which will then be connected to the table.
For our final presentation, our conversation with Professor Zeglin was extremely helpful in redesigning the system. We tend to thing very utilitarian with our projects, so having a discussion about presentation and style was very helpful. Our idea is to raise the frames and experiment with lighting over the weekend.
Frame fabrication will take place later this week. We want to leave enough time to test the size, shapes, and interactivity of our system to ensure we make the most use of the interesting properties of the auxetic materials.
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For our designs, we were able to start getting morphed geometries out of Rhino and Grasshopper. This was done using an attractor point, which was able to deform our auxtetic mesh. We are going to print and cast a couple of those this week.
Finally, we encountered a new auxetic design that appears to have a lot of potential for visual appeal. This design starts almost entirely solid, but can expand to many times its size using its cutout design (literature has the v at around -14 for some configurations and loads). We are aiming to spend this week working on making this design somehow, which presents its own challenges.
With only a few weeks left, we also are starting to work on the user interface system design. Since this will take a few days of work to complete, we are going to start designing and sourcing parts this week in case anything needs to be ordered.
]]>We have refined both our modeling and FEA processes so that we can run more of our designs each week. This is allowing us to hone in on exactly what behaviors we expect to see, and allows us to choose what we want our final auxetic to do.
We also started putting together a test plan, with specific elements that we want to change and test. This includes wall thickness and locations of irregularities.
Ensuring the validity of our simulations is a key step in our design process. We have printed two molds of potential designs, and are preparing to cast them. However, the quality of the molds may present an issue with the cast results.
Our next steps are to continue to iterate on our designs, cast two designs, and print 3 more molds by Wednesday.
]]>The start of the week was getting each of the softwares working, but by the end of the week it was a consistent process of design, testing, and revisions.
For the next week, we are hoping to:
- Have a design to print and cast
- Start a smoother process for making asymmetric/non uniform designs
- Begin thinking more about user interaction and how that will play a part
Our new prototype with the stiffer silicone worked much better, and informed us of what changes can be made to the shape of our grid.
Our new direction is based more on the novel properties of the auxetic material, and how that can be presented visually. Our idea looks like this:
This system has an auxetic mesh in the center, with 8 servos on the outside of a frame to manipulate the mesh. A user will interact with two joysticks that control the servos. The purpose of this system is to express the unique visual and kinetic properties of auxetic metamaterials in an interactive way. The mesh will morph and stretch in appealing and unexpected ways, which will demonstrate how auxetic materials differ from materials we interact with in everyday life.
Our next steps are working on the design of the system, as well as the design of the auxetic mesh.
Design elements for the auxetic:
- Infill density
- Non-uniform shape distribution
- Number of different auxetic meshes the user can interact with
- Images when deformed?
- Thickness/non uniform
Design elements for the system:
- Buttons vs joysticks
- Number of servos
- Constrained vs unconstrained sides
- How to implement shear
Workflow:
- Work on the deformation simulations
- Rework auxetic design
- Start designing system
Based on a gripper design from various sources, this actuator translates pneumatic pressure to a gripping force. Utilizing two different thicknesses of silicon on the top and bottom of the actuator, it is able to bend its “fingers” inwards.
The link to the files is here: https://drive.google.com/file/d/1d0tVN18X5IG1vFOcGbd8nepZ__HgYM8n/view?usp=share_link
]]>Root: P. Glick, S. A. Suresh, D. Ruffatto, M. Cutkosky, M. T. Tolley and A. Parness, “A Soft Robotic Gripper With Gecko-Inspired Adhesive,” in IEEE Robotics and Automation Letters, vol. 3, no. 2, pp. 903-910, April 2018, doi: 10.1109/LRA.2018.2792688.
This is actually a paper that I had previously found in the lateral search, funnily enough. It has 189 total citations, ranging from review papers to deeply technical applications.
Related paper 1: M. Ishida, J. A. Sandoval, S. Lee, S. Huen and M. T. Tolley, “Locomotion via Active Suction in a Sea Star-Inspired Soft Robot,” in IEEE Robotics and Automation Letters, vol. 7, no. 4, pp. 10304-10311, Oct. 2022, doi: 10.1109/LRA.2022.3191181.
This first reference paper covers a design that uses pneumatic legs that suction onto the surface, much like a sea star. It relates to the root paper in its materials and general pneumatic principles.
Related Paper 2: Q. Hu, H. Huang, E. Dong and D. Sun, “A Bioinspired Composite Finger With Self-Locking Joints,” in IEEE Robotics and Automation Letters, vol. 6, no. 2, pp. 1391-1398, April 2021, doi: 10.1109/LRA.2021.3056345.
This second paper is more human centered than the other papers written about here. Using a mixture of SMA, rotating joints, and silicone, the team was able to produce a robotic human finger as well as a three finger system. Though the method of actuation is different than the root paper, they reference its overall form and the way it bends, as well as the polymeric coating.
My general approach to this was to use IEEE to find a paper that I found interesting, then to look at the references to find a paper in a similar field that was interesting as well. From that paper, I looked into the citations to find two papers that used the root paper. I tried to find two that were related yet distinctly separate to provide more variety in this search.
]]>This paper covers a gripper that uses a specific kind of polymer that creates adhesion with the item that it is grabbing. Pneumatically actuated, the structure of the arm is able to bend, and the surface of the arm uses van der waals forces to create adhesion.
Course BibliographyL M. Garrad, G. Soter, A. T. Conn, H. Hauser and J. Rossiter, “Driving Soft Robots with Low-Boiling Point Fluids,” 2019 2nd IEEE International Conference on Soft Robotics (RoboSoft), Seoul, Korea (South), 2019, pp. 74-79, doi: 10.1109/ROBOSOFT.2019.8722812.
This paper describes a method of soft robotic actuation driven by boiling a fluid within a soft body. By increasing the temperature, and thus the pressure, and specifically designing the vessel with different stiffnesses and shapes, the team was able to induce some motion.
Paper Reference: W. Shan, T. Lu and C. Majidi, “Soft-matter composites with electrically tunable elastic rigidity,” Smart Mater. Struct. 22 085005, 2013, doi: 10.1088/0964-1726/22/8/085005
A paper by CMU’s Carmel Majidi, this paper shows off a metal wire/folded sheet encased in a silicone casing. They use both shape memory alloys and shape memory polymers to change the stiffness of the composite material by applying a current.
]]>I decided to approach this project from a product design lens by inspecting quintessential furniture designs. The Egg Chair was the most interesting and common piece that I found, and has an interesting purpose that is apt for soft robotic adaptations. Designed in 1958 by Arne Jacobsen, the Egg Chair was designed for two key reasons; to provide some privacy for the occupant of the chair, and to provide comfort and a sense of protection by nestling the sitter. It is a wonderful expression of form, function, and design, where its purpose and shape are one and the same. My personal interpretation is that the fact that the human is being encapsulated by an egg – or at least part of one – has something to do with the circle of life and the natural order.
My vision for the soft robotic adaptation would aim to improve the functionality of the chair, which in turn improves its value as a piece of design and art. Improving the comfort and privacy are exactly in line with the intent of the piece.
To achieve this, two different paths could be taken. One would use arms that would actuate to grip the sitter, such that they could walk into the chair and not realize that they had sat down. There are many types of solutions that have been developed that are soft arms, and they mainly differ by actuation method. One possibility would be an octopus-inspired arm that moves using muscular hydrostats made of SMA and polymer springs. These arms would not only make for a very adaptable and thus comfortable seat, but provide a sense of security through their pressure and grip.
Soft Robot Arm Inspired by the Octopus, https://doi.org/10.1163/156855312X626343
Another possible method would be to use inflatables to surround the occupant, providing the ultimate in comfort and security. Similar concepts have been implemented on much smaller scales, as robotic inflatable grippers, so the concept is fairly well documented. The pressure on the sitter would be extremely comforting (or possibly extremely uncomfortable), making it a great solution for the egg chair design.
Inflatable Particle-Jammed Robotic Gripper Based on Integration of Positive Pressure and Partial Filling, https://doi.org/10.1089/soro.2020.0139
In either implementation, the purpose behind the chair is realized to a further extent, which makes the changes artistically valuable.
]]>Ferrofluid based kinetic art and sculptures.
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