AM Super Shifters

[Jim Meyer]

We bought a couple of these and received them incredibly quick. Three or four days IIRC. It would take at least a week for our team to build these ourselves.

They certainly seem to be quite solid. They may be a little on the heavy side but the reliability I expect them to have more than makes up for their heft. We can spend a little effort lightening these and then use all that extra time making the rest of the robot lighter.

[JesseK]

We're pretty excited about our shifters; they came in a couple of weeks before the break and we had the opportunity to run one with just a single 2006 CIM motor and the servo. Our only problem was (still is) mounting it to our prototype frame, but that's because the mounts we made twisted when we welded them to the frame -- we're making a new process tomorrow to avoid this on the actual frame, but other than that we're very impressed with this transmission.

Also of note is that the keyed universal hub is fantastic mate for this transmisssion, and the hubs look like they only need a slight shave for the flat AM sprockets to fit over them -- something to consider if you plan to direct-drive one of your wheels from the transmission.

[AndrewN]

Originally Posted by kramarczyk

That depends, is the diagram a top view or a bottom?

Has to be a bottom view based on the vectors.
Quite the spin..

[Richard Wallace]

Originally Posted by Jim Meyer

We bought a couple of these and received them incredibly quick. Three or four days IIRC. It would take at least a week for our team to build these ourselves.

They certainly seem to be quite solid. They may be a little on the heavy side but the reliability I expect them to have more than makes up for their heft. We can spend a little effort lightening these and then use all that extra time making the rest of the robot lighter.

Ordered a pair Saturday about two hours after the kickoff presentation ended. Received them this morning about 10am.

As Jim says they seem very solid. Shifting is very smooth. And there is clearly some room to reduce weight by simple operations the team can perform.

[waialua359]

Originally Posted by Richard

Ordered a pair Saturday about two hours after the kickoff presentation ended. Received them this morning about 10am.

As Jim says they seem very solid. Shifting is very smooth. And there is clearly some room to reduce weight by simple operations the team can perform.

swap out the black anodized housing with aluminum spacers on the corners. We had to anyway since the black housing was too thin causing our gears to bind.

[Aarnat]

Hi all,
We have two AndyMark super shifters with two motors going into each transmission, and servos that change the gears. We definitely look forward to using them and seeing our robot fly around the track.

My question is: How has your team programmed them? My idea is to have two switches on the joystick: one to switch the transmission into the first gear and the second button to switch it into the second gear.

Also I read on the AndyMarrk website that we should ease off the accelerator when we shift; especcially since we are using the servo shifter. Has anyone had any problems with that?

Thanks!!!

[CardcaptorRLH85]

If you don't ease off of the power when you shift you will hear the most gut wrenching sound of gears at high speed crunching...we haven't managed to break anything since changing gears during autonomous mode wasn't really necessary last year and our driver slowed down when shifting during teleoperated mode.

I've been doing a bit of sensor code testing with our 2007 robot since I can't get any time with the '08 bot yet and I have noticed that after too many high speed shifts the servos tend to not make the gears mesh like they used to. I guess what I'm saying is, don't try your luck with the servos.

For your first question, I'll post the code that we used to make our servos go ^_^ We used a PWM Y cable to connect both servos to a single PWM output.

This part was in our Default Routine function (HIGH is defined as 1 and LOW as 0)

if (p1_sw_top || p2_sw_top) {gear = HIGH;}
if (p1_sw_trig || p2_sw_trig) {gear = LOW;}
Set_Gear(gear);

This is the Set_Gear function (the else is a just in case thing ^_^)

void Set_Gear(char set)
    {
        if (set == LOW)
        {
            pwm05 = 255;
        }
        else if (set == HIGH)
        {
            pwm05 = 0;
        }
        else
        {
            pwm05 = 127;
        }    
    }

This made it so that the top buttons for either the first or second controllers shifted to high and either trigger shifted to low.

[=Martin=Taylor=]

One of the spacers on our piston mount was .126" longer than theother one Causing the piston to not mount properly. We fixed this on the lathe...

Other than that, they are great. They run very smooth.

[R.C.]

One problem that I did have during the season was that we were shifting at 60 psi, not needed. It broke a couple of roll pins and pulled out the shifter block constantly. Make sure to have a regulator attached to the solenoid, 15-20 psi.

[Cory]

Originally Posted by rc_cola1323

One problem that I did have during the season was that we were shifting at 60 psi, not needed. It broke a couple of roll pins and pulled out the shifter block constantly. Make sure to have a regulator attached to the solenoid, 15-20 psi.

You can put a stroke regulating spacer in also.

[Alan Ing]

Interesting.

We used heavily modified AM super shifters this year and overall they worked very well for us. We have been using 60 psi in our shifting cylinders since 2003 including the AM shifters in 2006 and 2007. We never once had a problem with the roll pins, but this year, we had a few.

In Oregon, we sheared our first pin and one of the teams gave us a replacement. We thought it was a fluke or something we did when we modified the AMs. We then broke this other one prior to the eliminations which caused all sorts of excitement as we couldn't get a replacement. We ended up taking a drill bit the same size as the pin, cut it with a dremel and hammered it into the shifting dog. Thats the fun part of regionals, coming up with last minute solutions to put you back in the game. Surprisingly it was a pretty good fit and lasted the rest of the season including IRI.

Prior to Hawaii, I figured that we needed to add spacers into the cylinders to limit the stroke like Cory suggested. Figured they were in all our previous machines so that would probably solve the problem. Wrong....... Heading into the Finals we sheared our other dog roll pin during the first match which prevented us from driving straight as the transmission got stuck in neutral. During the break, we tried to change out the pin, but just could not do it in the time before the 2nd match so we locked it in 2nd gear and hoped for the best. At first it looked okay, but eventually we lost the transmission again and lost the match.

Coincidentally, the finals were against Cory's team 254, 233, and 2454.

I don't believe that it would have made a difference in the outcome of the match as our alliance was just outgunned, but it would have been nice to at least given you guys a good showing. Both our alliance captain (359) and us (368) went into the final match with broken machines. I think 2437 our alliance partner was still functional though.

Anyway, we replaced the broken roll pin with a dowel pin for the Championships and that seemed to solve the problem. I would highly recommend this small modification if you run 60 psi.

Prior to IRI we managed to shear the small roll pin in the shift block but we replaced those and went on to have a great time in IRI.

Well, perhaps the next time, we will do the smart thing and put a secondary regulator on the shifter and change all the roll pins to dowel pins.

I would highly recommend the AMs, our problem could have been due to the weight reduction modifications we did.

[falconmaster]

We used them in three regionals and Internationals and we never had a problem. We love them!
We have used both pneumatics and servos, We like pneumatics better. More reliable during autonomous. We sometimes would get a servo shutter upon the start of the autonomous period and the gear would be out for a fraction of a second,right when the robot controller would initialize. There fore we could not always go in a straight line.

[R.C.]

The supershifters in my opinion are way to havyy and don't need that third stage of reduction. Otherwise they're pretty good tranny's.