Sebastian
BujarskiHardware & robotics, drawn to spec

A soft continuum robotic arm inspired by an elephant’s trunk, built for Cornerstone Engineering II with teammates Yonas Bretschneider and Karl Leonardi. The arm features two independently moving sections, each section, respectively, pulled by four separate strings through a 3D-printed disc. Each string is controlled by a motor, and the four sections allow the robot to move dynamically in all directions, allowing navigation around obstacles.

I modeled and dimensioned the disc and spool components in SolidWorks, and wired all eight motors to motor controllers connected to a central Arduino board. I also coded the Arduino to control each motor independently, while retaining its ability to switch seamlessly between sections for fluid movement.

I’m involved in ongoing research with Northeastern’s Transformative Robotics Lab (TRL), under Professor Jeffery Lipton, and in collaboration with Northeastern Graduate students to design a bistable, radially expanding hexagonal structure. The project consists of a 2.5D cylindrical form made of repeating chevron unit cells that connect when flat and combine to form a cylinder. The cylinder can then alternate structures between a small, compact cylinder and a vertically and radially expanded cylinder.

I helped fabricate the unit cells and the final project. My work spanned many elements of the project, including laser-cutting 2D sheets of PETG plastic and forming it into the cylindrical shape. For later iterations, the team switched to a more precise 3D printing technique using PETG. With both methods, I used various tests to characterize each prototype, including manual measurement, full-stress strain characterization on an Instron tensile tester, and tracked deformation using motion capture tools.

To enable Instron testing, I personally designed a connector to securely link the prototype to the Instron, ensuring accurate data collection while allowing the cylinder to expand radially and rotate simultaneously. I also designed a clamp to secure each end of the structure, improving the prototype from 2D to 3D.

Two years with the National Eclipse Ballooning Program (NEBP), coordinating a team of eight across five high-altitude balloon launches. Payloads reached the edge of space, past 100,000 ft, on multiple flights, and instrumentation from one launch contributed to research on atmospheric gravity waves during a solar eclipse — work presented at the American Astronomical Society conference.

I designed the payload housings in SolidWorks and built them from foam-core panels, then built and programmed the ozone sensor module in C++ for onboard readout and logging. Each payload carried an Iridium satellite modem and GPS for tracking, recovered afterward with a portable ground station and directional antenna. I also helped coordinate launch-day logistics and team roles across the five missions.

With Renewable Energy at Northeastern (RENU), I designed the blade pitch-control mechanism for a three-person team's entry in a collegiate competition wind turbine build. Instead of a fixed blade angle, each blade mounts to a rotating shaft through a bearing housing, so pitch can be actively adjusted to the wind rather than staying fixed across every condition.

I modeled the full pitch assembly in SolidWorks — the bearing housing, mounting bracket, shaft, and hub — sized so the blade could rotate freely under load without binding. Active pitch control measured roughly an 8% efficiency gain over a fixed-blade baseline across varying wind speeds.