IR / Optical Relative Positioning System

Oct 2011 - Jan 2012

As a semester project working with the EPFL Biorobotics Laboratory, I designed, built, and tested a relative positioning system for mobile robots that uses modulated infrared or visible light to determine the range and direction to a modulated source. The sensor is insensitive to ambient light differences and other environmental factors. The system also allows low bandwidth communication and can be used to detect obstacles (using an onboard transmitter). The device is smaller than existing systems, and be easily adjusted to suit new environments.

prototype transceiver

first hardware revision

circuit board layout

block diagram of receiver

distance calibration

detector sensitivity

Dr. Alessandro Crespi, Dr. Juke Ijspeert (faculty)

final presentation, report, circuit schematic

relative positioning, circuit design, SPICE simulation, filter design, embedded systems, infrared and optical communications, EPFL

Simulated Robotic Salamander

Sept 2011 - Jan 2012

As a laboratory project for my Models of Biological Sensory-Motor Systems course, we investigated the locomotion and control of a 23 degree of freedom simulated salamander robot. We examined the different parameters controlling both walking and swimming using a sine-based controller and a central pattern generator (CPG). We found that, when optimizing the average speed through systematic tests and particle swarm optimization, the optimal gait and swimming trajectories are similar to the movement of actual salamanders. We improved our salamander model by adding stereovision and, using a biologically-inspired vision system with a neural network, created an autonomous salamander capable of tracking and walking toward objects.

walking salamander model

comparison of actual salamander and optimized controllers

configuration of central pattern generator model

transition from walking to swimming

Frédéric Wilhelm

draft report

robotics, salamanders, robotic controllers, central pattern generators, particle swarm optimization, visual system, Webots, EPFL

Autonomous Board Cleaning Robot

Jun 2011 - Aug 2011

During the summer of 2011, I worked in the Self-Organizing Systems Research Group at Harvard University. While there, I developed MAG-NEATO – an autonomous board cleaning robot. I designed the hardware and circuitry, sourced materials, machined parts, assembled the system, and programmed a series of autonomous behaviors. The sub-$100 robot features custom magnetic wheels, a 32 MHz microcontroller, LED indicators, input buttons, an accelerometer, bump sensors, reflective color sensors, an integrated battery charger, and an expansion port.

engineering model of MAG-NEATO

exploded view

magnetic attachment

top view

bottom view

overhead

erasing whiteboard

Dr. Radhika Nagpal (faculty), Dr. Nils Napp

presentation, circuit schematic

demo, magnetic attachment

autonomous mobile robots, education, circuit design, C programming, Atmel AVR, system integration, Harvard University

Force-Sensitive Multitouch Surface

Feb 2011 - May 2011

As a research project during the Spring of 2011, I worked with several other students to develop a force-sensitive multitouch surface. We built a functioning prototype and tested a series of different compliant surface materials which allowed us to estimate the pressure caused by objects and touches.

FTIR multitouch surface (source: Ars Technica)

preliminary results

Jacob Ghetto, Timothy Raymond, Seungwhan Moon, Dr. Mark Chang (faculty)

compliant surface materials, frustrated total internal reflection (FTIR) multitouch, Olin College