My Past Research and Design Project
For my
master's design project I worked at Cornell University's Human
Power and Robotics Lab. One of the biggest interests of this research group
is in passive walking where a robot walker is able to walk down a shallow slope
using only gravity as its power source. Several versions have been built
including a kneed 2D and 3D walker. My design project was to look into the
possibility of using powering an unkneed 2D walker such that it can walk on
level ground. Power come from motors connected to the ankles with sensory
feedback for leg crossing and heel collision. A collision-detection will force
the foot of contact leg to lift rest of the body up to increase potential
energy, allowing it to "fall" slightly and use the energy to take
strides. A leg crossing detection will force the swinging foot to retract and
prevent foot scuffle with the floor. A simulation was made of this system, and
the result appeared satisfactory.
For
my bachelor's design project I worked on an autonomous underwear vehicle to
join the AUVSI competition.
The task is to detect and retrieve an underwater beacon. I headed the
mechanical engineering sub-team and wrote the control algorithm for the
submersible's motion that consists of sets of PID to control pitch-depth and
heading-position. The hull is built from PVC tubes. Two Minkota electric outboard motors provide the main
differential thrusts while two smaller propellers powered by bilge pump motors
control the pitch and depth. For
streamlining, end-caps made of carbon fiber are used. Sensors include 4 hydrophones in a tetrahedral layout to
triangulate the source of the ping emitted by the beacon from a distance. For final approach two cameras are used to
provide binocular vision. The AUV won
2nd place at the summer 2000 competition.
I also worked for the Cornell Hybrid Electric Vehicle team during my junior year. The vehicle was modified Blazer using series hybrid. Two Solectria AC inductance motors were used to power the front and rear wheels. The APU was a gas-fueled four-cylinder engine connected to an alternator. I was a power-train engineer. The top vehicle was the Slipstream. It was built the year before I joined the team, though we maintained it in operational condition for the year. A single Solectria AC inductance motor powers the Slipstream, and it was backed by an APU fueled by CNG. Both vehicles were able to achieve about 40 mpg.