Well, I think that the description around our box explains it all.
We decided against dead-reckoning, wheel counting, and line following. Why didn’t you?
– Gompei, Leading the Blind since 2003
Well, I think that the description around our box explains it all.
Looks cool!
What exactly does it do?
You don’t line track, you don’t dead recog. You don’t jump over the wall and you don’t use electronics to determine where you are relative to the ramp. So how the heck does this work? 
were you using that at the UTC scrim?
No, the system was not available during the scrimmmage.
did you develop it in between, or did you have it made, but never put it on?
Well, WPI has been an active FIRST participant for the past 12 years…
Nah, just kidding; it’s been our plan from the start of our brainstorming. :yikes:
There are two ways you could do this, that i see.
One, ultra sonic sensors
Two, built a virtual court and used motor rotations to determine change and rate of change of position.
Somehow I doubt you did number 2. So what did u do?
It’s part of their CVT device…
It clocks the velocities of those via IR wheel and uses that input to determine robot postition.
Jeez guys, they showed it off enough last year… Doesn’t anyone remember it?
It’s nice to know you finally got it working.
Well it’s nice to know that you know how our CVTs work (afterall, we are in this thing not only to design great robots but also to teach and inspire 
).
But sadly enough, that box there has nothing to do with CVTs, mainly because there are currently no CVTs on the robot. :eek: But concerning those CVTs from last year, we did get “that thing finally working” for next-gen CVTs. 
I’m pretty sure they are using inertial sensors (i.e. an accelerometer) and integrating the value they receive to calculate their position. This would allow you to get quite accurate results, better than encoders, since the accelerometers can pick up wheel slippage and shoving.
I’m quite interested in knowing how you account for overall “drift” in the system… (?)
:: Nik
I’m pretty sure they are using inertial sensors (i.e. an accelerometer) and integrating the value they receive to calculate their position. This would allow you to get quite accurate results, better than encoders, since the accelerometers can pick up wheel slippage and shoving.
I’m quite interested in knowing how you account for overall “drift” in the system… (?)
:: Nik
Military has used inertial guidance systems in the past. Subs used them to navigate under the ice caps and in deep water, before the days of GPS. ICBMs used them to. The only problem is they slowly lose accuracy. They would also have to put the robot in the exact same orientation each time so it would know where to start. I doubt it would be very acurate after a hard hit because most accelerometers only work to a certain point.
A good point!
The system may end up having some drift but I’ll bet that those 190 folks have their act together when it comes to the overall package.
They’ve been building 'bots in Worcester for a whole lot longer than many teams have been around and experience ALWAYS helps…
Team #311 won’t be competing against them at any of the Regionals…but we’ll see you at Nats (again) and maybe even at BattleCry4…
Hey Chris…tell Matt C. I said Hi!
*Originally posted by Brian C *
**
Hey Chris…tell Matt C. I said Hi! **
Don’t worry, we’ll make sure he gets the message…btw, how you doing Brian?
Pretty good Deej, Thanks for asking
The usual butterflies wondering if the design is on the correct track or whether we “missed the boat” we’ll find out in a few weeks.
How are you doing this year with your other project and getting along without FIRST as much? I remember you were torn in your decision making a few months back. Hope it all worked out for you.
Will we see you in New Hampshire?
The project got put of till this summer…and I somehow managed to find some time to do some FIRST. I’ll most definately be there in New Hampshire, and with some luck, Seattle and Houston. See ya soon!
Congrats on the Excelence in Control! Would you care to give us a clue how you did this… and how you stayed within the electronics budget?
- Kristi, Team 30
We did a few things here…the first is that we designed an Inertial Navigation System (INS for short) that used a gyro to detect our heading on the field. It also used a dual axis accelerometer (x and y axis). Based on knowing our lateral accelerations and conversions and our heading, we are able to know where exactly we are on the field at all times (well the computer knows). this was our main navagation device during autonomous mode. this system also allowed us to use “heading hold” which when utilized, maintained a straight track, and if we were pushed off course, the motors would automatically course correct. In Houston, our INS system was not working correctly (funny how in seattle the weekend before it did), but the judges were really impressed with our control setup for the operators. we were able to use 16 different preset autonomous modes, using a rotary switch, and also determine where on the field we would go using x and y coordinates on our box. we also had a few automatic functions, like restow our wings, extender, and pitch in one button push. the different autonomous modes also allowed us to see out on the field who we were up against and paired with, and make ont he fly decisions, like after we set up on the field before we stepped away from the controls, see where the opponents lined up, and make a quick change if necessary before the match. Hope that answers the questions.
Adding to what DJ said, there are a lot of little “hidden” control components that we had. We have 1 keyswitch on the robot that turns off the rotating light; the benefit of this is to save our battery while working in the pits, as well as just to get rid of the annoying flashing. And you dont have to worry about losing the breakers or forgetting to put them back in before a match. Even if we forget to take out the key and leave it in the disabled position, as soon as the RC is reset the light will come back on.
There is another keyswitch on our operator controls which enables “maintenance mode,” allowing us to do such things as easily calibrating the joysticks.
We also built custom, intuitive controls to operate our wall. It consisted of two handles coming vertically up, with horizontal handlebars on each. To pitch the wall forward, just lean the assembly forward, to pitch backwards, lean back. To open the left wing, twist the left handle to the left; to open the right wing, twist the right handle to the right. To extend, click a toggle switch at the end of the right handle up, click it down to retract the extension.
And, our pivoting electronics board allowed for easy access to all electrical and mechanical components of the robot.