Brendan's Building the Future page


This is the page that I made for the Building the Future class (16-199) taught by Prof. Chris Atkeson. For my final project, I developed image tracking software. For the last nine months, I have been working with Ravi Balasubramanian on his graduate and thesis work in the field of legless locomotion. This is seminal work that has been previously unexplored. I am responsible for building and keeping a working prototype of our system. We call this system the Rocking and Rolling Robot, or RRRobot for short. Here is a picture of the robot: While Ravi does extremely difficult theoretical work involving the kinematics and dynamics of this system, I design the software and hardware to test the theory. We use a Cerebellum (created at CMU) to control the hobby servos that position the reaction arms.

A first step in this project was to create a software model that would allow the robot to produce arm motions that follow specified gaits. The solution that I came up with was to use a program running on a PC to create data arrays that would be stored in the program memory. I wrote a program that would run on the PC, take input parameters for the various gaits (sinusoidal, square wave, triangle wave, etc), and generate an array of servo positions. These position arrays would represent the servo positions with resolutions of 1/100th of a second.

I spent some time perfecting the art of having one program write another program. I eventually added calibration features so that in Cerebellum program, the servos could be zeroed for more precise control of the robot.

After we had a working version of RRRobot, we began testing to see whether RRRobot could follow paths predicted by Mathematica simulations of the system. Our preliminary tests involved videotaping RRRobot over the period of several minutes and observing its motion. The problem with this method is that RRRobot moves slowly, and we want to compare the motion at a high level of detail. The solution was to write software to track the motion of RRRobot.

Writing the software that tracks the motion of the robot was one of the most intensive programming projects I have done thus far.It required me to become familiar with many new concepts and explore efficient APIís that can process graphics.I chose C++ as the language because of its speed, direct memory access, and a wide variety of APIís that are available for different applications.For the memory intensive graphical processing, I used the Intel Performance Primitives library.In particular, I used their optimized routine for thresholding of the image and pixel counting.Finally, I used the Fast Light Tool Kit (FLTK) for the GUI interface.

After several months of programming off and on, I finally reached a finished project.The detailed methods that I used in the program can be found here.If you are interested in designing your own Rocking and Rolling Robot, you can find instructions here.Questions or comments are welcome.You can email me at bmeeder at Andrew dot CMU.edu††