Hyper 69 driving video

[baop858]

No pid yet, I do plan on implementing one though. I don't know about using a gyro for control, I would have to think that one though. We were going about 40% full speed. It was unstable because of the lack pid on the steering. But has anyone notice that the victor are uneven, like in one direction there's slightly less power than if it was going in the other direction with the same amount of difference from neutral, 127.

Edit: I just realized I could use the gyro to keep it going parallel with the length of the field. Thanks for the idea Q.

[Laaba 80]

Yeah, that will happen. What you need to do is create a function that will cut the speed down by a percentage, and put it on the motor that goes faster. It takes a while because you need to just guess and check, but trust me, in the end its worth it.
Joey

[Tapoore]

Originally Posted by baop858

No pid yet, I do plan on implementing one though. I don't know about using a gyro for control, I would have to think that one though. We were going about 40% full speed. It was unstable because of the lack pid on the steering. But has anyone notice that the victor are uneven, like in one direction there's slightly less power than if it was going in the other direction with the same amount of difference from neutral, 127.

What is your projected "full" speed?

[baop858]

Originally Posted by Tapoore

What is your projected "full" speed?

I think it was 10 fps at 120 lbs.

[CCCP]

you should test your driving on carpet
and take in to account that there are going to be other bots on the field while driving. Your statagy might be speed but other bots might be very slow so you need to learn how to steer better.
try to program your controler to be less sensitive.
also try some omni wheels if you have a problem with turning
nice bot

Originally Posted by CCCP

you should test your driving on carpet
and take in to account that there are going to be other bots on the field while driving. Your statagy might be speed but other bots might be very slow so you need to learn how to steer better.
try to program your controler to be less sensitive.
also try some omni wheels if you have a problem with turning
nice bot

Umm I'm pretty sure that was on carpet. If it was his first time driving then yea, he should learn how to steer better. Omni's wouldn't really work with quadresteering.


I like it a lot. I can't believe that's only 10 fps. You were zipping around the track like crazy (and losing like 150 points in the process for penalties for going backwards [yes I know you know you were going backwards]).

[Ken Streeter]

Originally Posted by baop858

... But has anyone notice that the victor are uneven, like in one direction there's slightly less power than if it was going in the other direction with the same amount of difference from neutral, 127.

Short answer: use 132 for the center, rather than 127. Yes, this is contradictory to everything in the IFI documentation and on their web site. However, our empirical tests bear this out again and again, on different motors. How did we get to this determination?

Well, we observed in 2005 that our robot's right side and left side drive motors seemed to be mis-balanced, and wrote the matter off to the fact that the motors on one side were going forwards and on the other side were going backwards.

In 2006 when programming a PID control loop for shooter azimuth control, we became convinced that the actual center for the victors is 132, rather than 127.

In 2007, we did yet more PID control for a multi-jointed arm, and again found the center to be 132.

In 2008, with PID control for the rack-and-pinion steering on our "Speed Racer" we have again found the PWM center to be at 132. We don't have an oscilloscope to verify this, but have verified this empirically again and again.

For another datapoint, check out the camera control code at kevin.org. Oddly enough, you'll find that the center value used is 132...

Best regards,

--ken