pic: 254 Drivetrain

[soezgg]

bad $@#$@#$@# wheels.

[Solace]

just a question, but did you use open or closed loop for steering? because it would seem that at the speed the robot usually goes, it's turning speed is much too fast for it to be controlled by open loop.

[JessR]

But I think if the chain is open loop, you can only drive a few feet befor it falls off? The closed loop works much better for that.

[Cory]

I think he's talking about programming...

[Aignam]

Gee, Kingman had something really similar to this...

[Greg Ross]

Originally Posted by JessR

But I think if the chain is open loop, you can only drive a few feet befor it falls off? The closed loop works much better for that.

Wiseacre engineer.

[Solace]

i mean in programming. I know that 254 and 60 both did the steering wheel/joystick combo, but how exactly did they do the controls in programming?

[Greg Ross]

Originally Posted by Solace

i mean in programming. I know that 254 and 60 both did the steering wheel/joystick combo, but how exactly did they do the controls in programming?

Yes. I'm still waiting for them to answer too. I think I know the answer (which is that it's purely open) but I'll wait for the proverbial horse to speak.

[Travis Covington]

Originally Posted by gwross

Yes. I'm still waiting for them to answer too. I think I know the answer (which is that it's purely open) but I'll wait for the proverbial horse to speak.

Jay Lundy talked about this in one of the other threads.. Well kinda...

http://www.chiefdelphi.com/forums/sh...3&postcount=14

[Greg Ross]

Originally Posted by Travis Covington

Jay Lundy talked about this in one of the other threads.. Well kinda...

http://www.chiefdelphi.com/forums/sh...3&postcount=14

I guess I was wrong. Alex Baxter's post (10intheCrunch) in the same thread comes close to saying that they (254) used closed loop control.

[Cory]

Greg- as I understand it, they used closed loop control for their arm.

[Jay Lundy]

The drive train loop is open when you are turning (see the other posts linked to for more information about that), but the straight drive loop is closed. The striaght drive code is run whenever the steering wheel is at the center position +- a certain deadzone. It uses the proximity sensors to get a speed error (left count - right count). For the robot to go straight, the speed error should be 0, but it usually isn't, so the speed error is multiplied by a constant and subtracted from whatever side is going faster.