Quote:
|
Originally Posted by KenWittlief
the time it takes is one fourtieth of a second for the feed back loop to see that 'something' is trying to push the robot sideways, when its not suppose to be going sideways, and the SW corrects the power to the motor to force it to do what the driver wants.
This works to stablize castors, it also works if you hit a ball, if a bot hits you, you encounter a change in resistance (like driving on carpet or on the smooth surface)
and it worked last year going up the ramp at an angle.
The PID loop doesnt care whats trying to push the bot off course, it senses the slightest change in yaw rate, and applies an immediate correction.
We used it last year - the bot steered like it was a large servo.
|
At 10 fps, that's 120 ips, I've travelled 3 inches in 1/40th of a second. That's about 120 degrees of rotation on a 3 inch caster - it has already spun around and pushed me off position by then.
If you want to drive all over the field at part power because you're shutting down one motor or the other all the time to compensate for instability in your drive system, please do. We'd love to have you as an opponent.
Spikey, I'm impressed that you won 2 regionals with casters, but I'm betting it's not because of the casters right? You just focused your resources on other parts of the robot rather than on the drive system, so you had a robot that played all aspects of the game and didn't just drive.
The question of this thread is, what do you think of casters. My answer - not much.