JeffCarothers_Portfolio

Jeff Carothers / mechanical design portfolio /

Singularity Drive / Omni-directional drive / SB Thesis / spring 2014 /

For my undergraduate thesis, I designed an omni-directional drive system for mobile robotics. Dubbed a “3-Point Singularity Drive,” this system was able to change it’s thrust vector instantaneously to any direction with infinitely-adjustable speed and torque. I designed a simple control scheme for the robot that enabled it to closely track a given trajectory.

Singularity Drive / Omni-directional drive / SB Thesis / spring 2014 /

The drive system relied on three small, spherical wheels, each of which contacted the ground plane in one point and provided a stable base for the robot. In its neutral state, the drive axles were orthogonal to the ground, causing the wheels to spin in place like tops. If those axes were tilted, however, the wheels would begin to roll. By tightly controlling the tilt angles for all three wheels, I could command the robot to move in any direction I wanted.

Singularity Drive / Omni-directional drive / SB Thesis / spring 2014 /

The robot’s chassis utilized three identical drive modules, which contained the gimbal, wheel, servos, and drive motor required. This helped to simplify the design, manufacture, assembly, and eventual control of the robot. Using simple PID control on the drive axles and open-loop trajectory control, the robot was able to closely follow given routes. Check out my full paper at: MIT DSpace.

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Glow / interactive yoga mat / MIT 2.009 / fall 2013 /

Glow is the world’s first fully interactive yoga mat. Designed over 10 weeks by a team of 18 MIT students, Glow uses a grid of embedded LEDs and piezoelectric pressure mapping sensors. The system is capable of teaching yoga beginners many different poses and techniques from the comfort of their own home. As one of the lead mechanical designers for the team, I was in charge of designing the electronics housing at the end of the mat.

Glow / interactive yoga mat / MIT 2.009 / fall 2013 /

The final housing was built with four 3D printed pieces that were laminated together into one large enclosure. A thin strut along its length added extra strength and crush resistance, and thermo-set threaded inserts provided attachment points to the clamp holding the mat. After construction, the enclosure was finished with hard enamel and polished smooth.

/ Mobile Autonomous Systems LAB / winter 2013 /

MASLAB

The 2013 MASLAB Competition required teams to build an autonomous robot capable of finding, collecting, and depositing small wooden balls. With only 3 weeks to design and build the robot, our team utilized rapid prototyping design and CNC machining. As the head mechanical designer for the team, I led the development of the robot and helped my team win second place.

MASLAB / Mobile Autonomous Systems LAB / winter 2013 /

Largely constructed with laser-cut acrylic and waterjet aluminum parts, the frame could be cut out, constructed, and tested very quickly. New designs could be implemented in mere hours for low cost and minimal effort. Other design features, like an adjustable gear box, modular architecture, and hot-swap feature mounts, allowed us to test different designs efficiently.

Tightrope Segway / MIT 2.14 final project / spring 2013 /

Designed for my feedback control class final project, this 3-DOF robot was capable of balancing on a tightrope with only one wheel. The dual-PID control system was designed in MATLAB and implemented in Processing on an Arduino microcontroller.

Aztec Yoyos / MIT 2.008 design project / fall 2012 /

As a part of the 2.008 Design and Manufacturing II class at MIT, a small team and myself was tasked with manufacturing 50 copies of a unique yoyo design. We created the Aztec Yoyo, an injection molded spinning yoyo.

Each half of the yoyo included a small weighted spinner for added entertainment value, and was made with only five parts total.

Aztec Yoyos / MIT 2.008 design project / fall 2012 /

In addition to learning a lot about Design for Assembly and Design for Manufacturing, this project was my first introduction to full CNC machining. Each of the molds for the yoyo parts were machined from aluminum billet, and my team was required to take Solidworks CAD files, modify them in MasterCam, and then generate our own G Code for machining.

RoboArm / MIT Biomimetics Lab / summer 2012 /

As an Undergraduate Researcher in the MIT Biomimetics Lab, I was in charge of the design of a robotic arm with the same degrees of freedom and range of motion as a human arm. Additionally, it had to be extremely durable, fully modular, low cost, and quick to manufacture. Over the course of three months, I developed a design for a robust 3D printed arm. Using advanced Dynamixel servomotors embedded within the arm itself, RoboArm could lift 15 pounds, maneuver objects precisely, and was durable enough to withstand a direct hit from a baseball bat. Additionally, with only seven machined parts, the design was low cost and very easy to build.