Background

While working on last year’s project, we noticed issues regarding the delamination of actuators that occurred while using the two-part mold. The delamination caused our edible actuators to have a relatively low success rate, as even the slightest amount of air sheared the air cavities from the base. This made the actuators unsuitable for rigorous actuation and multiple actuation cycles. 

Evident from our project last year, we are passionate about increasing the accessibility to soft robotics. It allows for more students to have their interests in material science and engineering piqued the same way soft robotics piqued our interests in those fields. To increase accessibility, we set out to design an actuator that could be produced with ease. We hypothesized that the use of a soluble internal structure could be used to create the air chambers for inflation, making the fabrication process simpler. Our team believes that this process of fabrication has never been done before.

Our mentor implemented soft robotics into the engineering curriculum at our school. One of her students, Ed King, was building the Soft Gripper from the Resources for Educators when he too struggled with the delamination of the actuator. He then had an idea: rather than using a two-step process and have the structural integrity rely on the layers weakly fusing together, why not use a single mold to create the entire actuator in one go? The key to his new method, dissolvable inserts, would allow him to use a single mold to create actuators. No lamination required. 

He decided to cast silicone around a polystyrene (styrofoam) insert and dissolve it using acetone after the cast has cured. This idea of soluble actuator inserts marked the beginning of the King Actuator.

ConceptualizationFirst Prototype by Ed King   Actuation

Figures 1, 2, and 3: Initial design sketches, first prototype, and first successful actuation

The images above show the conceptualization, the fabrication, and the actuation of one of Ed's first King Actuators. The difference in density of the silicone and styrofoam materials caused the styrofoam to float. While we were excited about Ed's innovation, we knew there were was room to improve, and thus, our iterative design process began.

At the same time, the ceramics teacher at our school, Mr. Raeder, approached us with a problem: he wanted a more effective method of teaching his students how to throw a pot. He described the difficulty of instructing complex, nuanced motions to his students. Mr. Raeder told us, "If a student’s relaxed hands could feel pressure to move the correct way using soft robotics, it would be very efficient and convenient.” We believe that using a glove similar to that described in Polygerinos et al. (2013) would be ideal in aiding a student's learning in ceramics and reduce the time necessary to become proficient in the art.

Teaching Student

Figure 4: Mr. Raeder teaches a new student how to throw a clay pot

Our goal for the 2018 Soft Robotics Toolkit Competition was to create a single-pour actuator manufacturing process using a dissolvable insert in order to prevent delamination and increase actuator durability. From the start of our research, we defined our success as creating an easy-to-make and durable actuator design. In tandem to our project, we would like to develop the foundations for the teaching of ceramics through soft robotics. While our project is not centered around teaching ceramics, we believe that soft robotics has a place in teaching anything that requires muscle memory or complex, nuanced motions, and would like to make progress in that field with this new application.

Final Actuator

Figure 5: A King Actuator prior to the polystyrene insert being dissolved.

Haverford Soft Robotics 2018