My name is Meaghan Pearson, and I am a senior Mechanical Engineering transfer student at UC Berkeley. This Summer, I was fortunate enough to work at the MuM, Institute of Mechanics and Ocean Engineering, at the Technical University of Harburg-Hamburg (TUHH). My project was conducted under the supervision of Dr. Malte Grube, a researcher studying soft robotics. My project partner, Jordi Riera, and I were put in charge of developing, prototyping, and building a modular, fluidically actuated underwater soft robotic arm. The long-term goal of the project was to attach the robotic arm and gripper to a previously built underwater robot within the lab to aid in exploration in difficult environments.
Although most aspects of the robot were developed together, my primary focus of the project was to create the fluidic pump and gripper mechanism. Jordi focused on building the modular actuator, which means that multiple actuators could be added or removed from the soft robotic arm to extend or decrease the range of motion.
The pump was designed to fluidically pressurize and depressurize the actuators and gripper. The final design was based on piston pumps, with syringes as the chambers to conserve space. Each syringe is filled with water via NEMA 11 motors and T8x8 lead screws. A platform restricts the barrel flange of the syringes to ensure that the only movement is linear displacement of the plungers. A piston pump was used for this project because it allows for extremely precise measurements and excellent data collection. This helps create the neural network utilized to control the soft robotic arm’s movements.

The first step in the process was intensive research of plausible pumps and discussions with my supervisor. Because this is not a well-researched topic, there were multiple iterations of the design to ensure it fit within space, torque, and speed constraints. Below are the different versions of the models I created to reach the final design.

From left to right, the first version was too large and used NEMA 17 motors, which produced too much torque. The second design (middle) was also too large and had unnecessary additional parts; the third version was still too large; however, it was the first design to incorporate specially designed plungers that were directly attached to the T-Nut. This allowed for fewer parts and less possibility of losing linear displacement.
The final CAD design is shown below from top and bottom views.

Below is the final pump, 3D printed with PLA. The overall parts list (not including the 3D printed pieces) includes: NEMA 11 stepper motors, 5mm to 8mm couplers, T8x8 lead screws, T-Nuts, 3mm threaded support rods, tubing, and 5ml syringes.

Additionally, to control the pump, I built a PCB with motor drivers, Raspberry Pi Pico, and capacitors. It can be seen above in the bottom left of the image. In addition to the pump, I designed the soft gripper for the robotic arm. It was created from poured silicone. The original design is shown below, with a connector and four “fingers” that were attached to the connector. Below is left to right: connector, 3D-modeled mold, and the “finger” prototype.

There were some difficulties with leakage and manufacturing of this design. Below is an image of the modeled new design with chambers allowing for the pressurization of the gripper:

An additional layer of soft silicone was attached to the gripper to seal it and allow for pressurization. The images below show the finalized gripper being pressurized:

In addition to the work shown above, Jordi was working on creating the three-chamber, modular actuator and neural network. Below, to the left is a drawing Jordi created showing the differential pressurization of the actuator, and to the right is an image of the finalized product.

Below is a video link of the working soft robotic arm. This video is sped up and shows very incremental movements because it was taken during data collection to produce the neural network. Jordi was able to program the neural network and, using the data, feed specific coordinates into the program, causing the arm to move to that precise position.
This Summer abroad was the best Summer of my life. I had an amazing group of coworkers and friends and the most dynamic, interesting, and enjoyable project I have ever worked on. This internship made me realize I want to pursue a career in soft robotics and biomimicry. All this was possible due to the GLOBE scholarship. GLOBE paid for almost two months of rent, allowing me to comfortably live near my job, just a ten-minute walk to work.

In addition to my wonderful internship experience, I enjoyed the beauty of Germany. My friends and I from the internship travelled all around Germany on the weekends. We visited Munich, Cologne, the Eibsee, and Berlin. I also traveled to visit my friends in Ibiza and Oslo, Norway. My home city, Hamburg, was a vibrant city with endless things to do and see. My favorite activities were to walk around the Alster Lake, especially during sunset, and go to Stadtpark to watch the World Cup games with my friends.


I will remember this Summer for the rest of my life, and I hope that students in the future will utilize the resources and support that GLOBE offers to enjoy this wonderful experience without financial strain.



Written By: Meaghan Pearson
UC Berkeley Mechanical Engineering Undergraduate















































