Automatic shifting software

[StevenB]

I plan on having manual override, just in case.
Does the robot jolt when you shift, and do you compensate for this somehow?

[efoote868]

Our team purchased 2 AM servo shifters, so its now the programmers job to mess with them a bit.

I think with what we're going to do is have automatic shifting, once a gear-tooth counter counts to whatever, then decrease motor outputs automatically, and then "gradually" bring them back up to speed, depending where the joy is at.

We also plan to have a switch to manually override the shifting... low, high, auto.

Hope this helps!

[Tom Bottiglieri]

Originally Posted by efoote868

Our team purchased 2 AM servo shifters, so its now the programmers job to mess with them a bit.

I think with what we're going to do is have automatic shifting, once a gear-tooth counter counts to whatever, then decrease motor outputs automatically, and then "gradually" bring them back up to speed, depending where the joy is at.

We also plan to have a switch to manually override the shifting... low, high, auto.

Hope this helps!

Remember, it will take about half a second for the servo shifters to change gears. It seems unless you have a rock solid shifting algorithm, you will be wasting a lot of time on the field going nowhere and may experience quite a bit of "shift shock".

[Greg Marra]

Personally, I think that a driver should be able to handle shifting during a match himself. I find that usually you don't need to shift more than 5 or 6 times tops per match. Having the robot shift on its own seems prone to unwanted behavior.

Unless you can make the robot shift better than a person (like a CMUCam aims better than a person), why make it do it?

[JessR]

We have used a 2 speed tranny with encoder driven autoshifting the past 2 years and find it works well. As with Sparx above, we have offset the upshift & downshift points. We also reduce power for the 1/4 second or so it takes to shift.
Similarly our (homemade) 2 channel encoders give a quadrature signal that lets the software keep an absolute count & if you're going forwards or backwards.
Note in software you can 'have it all":
A toggle switch on the driver controls is labeled 'auto - manual'
In manual mode the trigger upshifts & thumb button downshifts.

With velocity based shifting, autoshift is just the thing for those closing seconds when you are distracted, burnt out & need to just peg the joysticks and head for home.

[Alan Anderson]

Originally Posted by Greg Marra

Unless you can make the robot shift better than a person (like a CMUCam aims better than a person), why make it do it?

The thing is, you can make the robot shift better than a person. A well-programmed robot knows how fast it's going, knows what gear will provide the best power at that speed, and knows how to make the shift smoothly.

[StevenB]

Has anyone done automatic shifting with the DeWalt transmissions? Are there things about them that make shifting different?

[chris31]

Taking what Alan, Jess and Greg said I think that the best idea is to have an manual and auto switch. That way the user can control it when he/she needs to and then turn on auto when it would best be done by the robot calculations.

[gnirts]

How does one figure out at what RPM/velocity/joystick position shifting is ideal? (We are using four small CIMs and Dewault transmissions.)

And how should the lookup table be structured? Why should it be joystick (throttle) position vs. speed? In a manual shifting car you get back RPM (tachometer) vs. speed (speedometer) and shift based on that (I think...). So shouldn't you shift up when your motors reach a certain RPM, while lowering power to the motors to maintain constant speed? That way you can continue going faster.

Thanks in advance,
Robinson

[gnirts]

Anybody?

[Rickertsen2]

I see that you list yourself as from ATL. What school are you from?

[gnirts]

Originally Posted by Rickertsen2

I see that you list yourself as from ATL. What school are you from?

Henry W. Grady High School, right downtown. Will I see you at the scrimage?

BTW, I have reposted my question a little more clearly here.