Assignment 1: Formal Letter

 

Summary and Analysis Draft #4

 

MEC1281

 

Woravuth Chong (2003006)

 

According to the article “Soft robotic arm...” (Matheson, 2020), researchers from the Massachusetts Institute of Technology (MIT) have developed a system comprising of sensors with high compliance and an information processing model that allows a robot equipped with these to know its position in 3D space and move about efficiently. The sensors are wrapped all around the robot’s body like skin. Traditionally, robots get their configuration info from a complex system of cameras, which are unfeasible for actual soft robot applications. Truby, one of the researchers, said that “We’re sensorising soft robots to get feedback for control from sensors, not vision systems, using a very easy, rapid method for fabrication.” According to Matheson, Truby also said that the entire system is still inadequate, but it is a crucial foothold from which advances in soft robotic control can be made. Moving ahead, researchers are looking at designing better sensors and learning models to cut down on training for new robots.

 

Although the soft robotic arm is a better alternative than the traditional robots, its development has yet to be perfected. Researchers are seeking ways  to improve the arm's effectiveness with regard to the material used for the robot’s sensors.

 

One way to improve the arm’s effectiveness it to use a different kind of material. According to Truby, the materials used for the sensors are "sheets of conductive materials used for electromagnetic interference shielding" that are found anywhere. Although these materials are piezoresistive and cuts were made due to the inspiration of Kirigami, the material did not stretch a lot. Using such material is not ideal as it limits the soft robots' flexibility.

An alternative to the material that Truby used, carbon nanotubes and flexible materials such as conductive hydrogels can be considered. In the article, “Carbon nanotube…”, (Hsiao, 2020), it is mentioned that the multi-walled carbon nanotubes (MWNTs) are highly deformable and mechanically durable. This shows that the material MWNT can stretch, bend and twist without breaking or having permanent deformation. The material used is made by integrating the MWNT into a “gelatine solution followed by the introduction of a crosslinking agent” (authors’ names, date). Using this material for the soft robot’s sensor will allow the robot to be more flexible than the sheets of conductive materials used. The carbon nanotube can be integrated into the flexible material to withstand deformability.

 

In another article, “Rubbery electronics …”, (2017), it is stated that the alternative to the kirigami method, “An alternative route to eliminating the burden of constructing dedicated architectures and the associated sophisticated fabrication process is to build stretchable electronics from intrinsically stretchable electronic material”. A similar method of making a flexible material is used. The researchers used a rubber composite as a stretchable semiconductor and had nanoparticles. The results were that the material is able to maintain its characteristics after stretching 50% of its size.

 

In conclusion, Truby's design is a simple design that does only requires common materials to craft and does not require multiple processes for it to be ready to use. However, using the method of coating nanoparticles with stretchy and flexible materials and using it as a material for the soft sensors will allow the robot to be able to move about more efficiently.

References

 

Hsiao, L.Y., Jing, L., Li, K., Yang, H., Li, Y., & Chen, P.Y., (2020, May) Carbon nanotube-integrated conductive hydrogel as multifunctional robotic skin. Carbon, 161. https://doi.org/10.1016/j.carbon.2020.01.109

 

Kim, H.J., Sim, K., Thukral, A., & Yu, C. (2017, September 8) Rubbery electronics and sensors from intrinsically stretchable elastomeric composites of semiconductors and conductors. Science Advances, 3(9). https://doi.org/10.1126/sciadv.1701114

 

Matheson, R. (2020, February 16). Soft robotic arm uses flexible sensors to understand its position. Control Engineering. https://www.controleng.com/articles/soft-robotic-arm-uses-flexible-sensors-to-understand-its-position/