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Our Control System:
The CODE is posted here and on the CODEX
We tried to keep operation as simple as possible for the operator, since we knew it was going to be hard to control because of its speed (right around 12ft/s) so we stayed with only one joystick.
In normal mode if the operator pressed no buttons it locked all four wheels straight ahead and steered in a tank setup. The speed defaulted to somewhere around 50% of maximum.
The top button activated our 4 wheel steer, such that when it is held down the robot will keep its orientation but the drive will follow the joystick in any direction. Again another plug for LeoM, he came up with a really sweet algorythm for the steering angle in one line that works flawlessly since PBasic couldn't do it.
The trigger then kicked everything into full speed, we usually came off the line in turbo 4 wheel steer to try and hit the center goal no matter where we were lined up at.
As a last helper for the driver, our operator interface board switched the orientation from front to back with a switch so that made figuring out the inputs when the robot is reversed no longer necessary.
Now that we have tried it somewhat successfully I would probably go to the mechanical setup more like Team 111 with independent front rear steering to give you more options. I doubt we will have to push like last year so the high speed setup might work this year. Last year we didn't have the right ratio or traction to rotate a goal about the center of the robot, so we had to rotate around the goal then take off with it. A system like Team 111 where the front/rear oppose each other in direction would probably have worked better since we scrub off so much power to use tank steering.
I think the hardest part of using the single joystick was the inverse trig functions in pbasic and now those are available to all teams.
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