Auburn University Journal of Undergraduate Scholarship e Design and Fabrication of a Novel Multistage Soſt Robot Rizwan Halani, Chad Rose, and Avinash Baskaran e purpose of this research project was to design a soſt robot capable of moving a rigid platform above the robot with three balloon-like actuators created by 3D printed molds as opposed to the traditional method of using linear actuators [1]. Having robust structural compliance and variable geometric contact surfaces, the soſt-robot will possess improved maneuverability in enclosed spaces compared to traditional wheeled or legged robots. To conduct this research, certain design criteria had to be met. e balloon must be able to expand without bursting, it must return to the original position when deflating (the origin of the structure must not shiſt), and it must expand uniformly. e simplest shape that meets these three criteria is a sphere. Although print- ing three separate balloons and attaching them together was a viable option, a connected approach, with a single unibody design containing three independent cham- bers, allows for more precise movements as the distance between the centers of each chamber can be more finely controlled. To achieve uniform expansion, care had to be taken to create a uniform spherical mold. To create the mold, several iterations of the design were made. e final silicone mold can be seen inflating in Figure 1. To allow minimal deviation from the origin of the over- all three-pocket structure, the chambers were printed in a large structure already connected to one another. To expand without bursting, the material chosen was silicone [2][3]. It was tested with sample balloons and did not warp due to continuous inflation and deflation. Manual actuation of the balloon proved that the design was a viable solution. Another design target was imple- menting closed loop control of the system. A pressure sensor [4], pneumatic solenoid [5], and Arduino [6] were added in line to each cavity to create a closed loop system. e pressure sensor recorded data and sent the data back to the Arduino, which regulated the solenoid. e solenoid would release air if a balloon needed to deflate. Further research will address (1) how to design the ac- tuator such that multiple stages could be stacked with- out disrupting the pneumatic supply lines, (2) how to best implement an IMU to track the position of the rigid platform, improving the tube-balloon interface to reduce air leaks to improve performance, and (3) how to obtain data at different rates with the Arduino. Creat- ing a soſt-body actuation approach could be beneficial in applications where traditional mechanically actuated parts would fail. For example, a wheeled robot might slip while climbing up a pole, but the soſt-actuated ro- bot would have multiple points of contact to the surface it is climbing. Statement of Research Advisor Rizwan’s research is the first exploration of simple, soſt robot capable of peristaltic locomotion and manipula- tion tasks in my lab and laid the groundwork for future studies involving pneumatic actuators. –Chad Rose, Mechanical Engineering References 1. Liu, Min-Jie, Cong-Xin Li, and Chong-Ni Li. “Dy- namics analysis of the Gough-Stewart platform manip- ulator.” IEEE Transactions on robotics and automation 16.1 (2000): 94-98 2. Sun, Yi, et al. “Soſt oral interventional rehabilitation robot based on low-profile soſt pneumaticactuator.” 2015 IEEE International Conference on Robotics and Automation (ICRA). IEEE, 2015. 3. Smooth-On EcoFlex, 00-30, https://www.smooth- on.com/products/ecoflex-00-30/ 4. SparkFun Qwiic Micropressure Sensor, https://learn. sparkfun.com/tutorials/sparkfun-qwiic-micropres- sure-hookup-guide/al5. 12V Pneumatic Bidirectional Solenoid Valve, https://www.amazon.com/4inch-Nor- mally-Closed-Electric-Solenoid/dp/B074Z5SDG3 5. 12V Bidirectional Pneumatic Solenoid, https://www. amazon.com/4inch-Normally-Closed-Electric-Sole-