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This is a system that is very similar to what we have. We have what is called INS, Inertial Navigation System. Not being a part of the electrical design team, I do not know the fine details of it all, but I can give a brief overview, and a detailed whitepaper is in the works.
We spent very much time debating how we should approach the autonomous time. After some debate, it was determined that dead reckoning and line tracking would not be very accurate or very quick, respectively. An encoding wheel was discussed, but again... if we are up against a solid stop and the wheels spin on the carpet, our calculated position is no longer the same as our actual position.
Soooo, using a gyro chip and dual-axis accelerometer, we are able to determine our exact position on the field. Our gyro operates in very much the same way as 111's, securing us with "heading hold" to ensure that we are perpendicular (or parallel depending on how you look at it) to the ramp, and if we get spun around will take the most efficient wheel path to correct itself. The dual-axis accelerometer reads the X-Y acceleration of the robot on the field. We take the double integral of these values to read X-Y position. By converting these "INS units" to real-life units, we are able to tell the robot where to move on the field, using knobs on our human control station; we can chose X and Y position -- the ability to choose which side of the ramp to go up, and how far to go along the ramp. We also account for the angle of going up the ramp, because our acceleration is now being miscalculated because of the 32 ft/s downward acceleration which now becomes a component of the X-Y coordinates. Possibly under development is way to detect if we are flipped during autonomous which would allow us to self-right ourselves autonomously!
I am not too sure of WildStang's drive system, but it too seems as if it may be similar to ours. Our robot name this year is "King CrabGoat 2k3." Perpendicular to our main drive wheels, we have a fully redundant driveline that is known as the "crab system." These 4 kicker wheels drop down in 0.2 seconds and lift the entire robot with an over-center mechanism, so we are able to almost instaneously change our direction of movement 90 degrees.
Up to this point, I had not heard of any other team using an actual "guidance system" such as we have done. I give congrats out to WildStang, and would definitely love to see it in action.
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