Andy Mark Super Shifters

[Jecht22]

Hey I wanted to ask a few questions to the teams who have used the andy mark super shifters before. Does it make a big difference to shift them using pneumatics or servos. Assuming the answer to this question is that pneumatics will be better, is it possible to use electrical solenoid actuators instead.

[Grim Tuesday]

The pneumatic shifting is definitely better. When you only have 120 seconds to play with, if shifting takes 1-2 seconds, it is wasted time. You also might have to stop driving to shift. With pneumatic, it is instantaneous.

The only downside to pneumatic that I can see is the requirement that you have to have a compressor and added weight. Though, if this is the only pneumatic thing on there, you may be able to get away with pre-charging some tanks.

[Matt H.]

Originally Posted by Jecht22

is it possible to use electrical solenoid actuators instead.

It might be, but the performance won't be the same as pneumatics.

R48J limits you to Solenoids rated at less than 10 Watts continuous duty:

electrical solenoid actuators, no greater than 1 in. stroke and rated at no greater than 10 watts continuous duty at 12V

A quick look at McMaster-Carr shows that all their solenoids meeting that rule have a maximum force of less than or exactly 5lbs.

In contrast the 3/4" bore pneumatic cylinder recommended by andymark has a force of about 25lbs.

Also, designing mounting brackets to interface the solenoid with the shifter will be an annoyance.

[ajlapp]

Team RUSH, FRC27, has used servo shifting on our SS transmissions since 2008 without incident.

We shift on the fly with no issues. We couldn't be happier with it.

[DonRotolo]

We avoid servo shifting because it is a little sluggish. But it is reliable enough.

[PayneTrain]

I'd go for the pneumatics if your weight can give up all of those components, but don't anticipate your robot will make a giant decline in quality if you go with the supplied servo.

AndyMark knows it's reliable enough to include it in the package. They don't ship bad stuff. (Here's to you, RS-775s!)

[IndySam]

Originally Posted by Matt H.

It might be, but the performance won't be the same as pneumatics.

R48J limits you to Solenoids rated at less than 10 Watts continuous duty:



A quick look at McMaster-Carr shows that all their solenoids meeting that rule have a maximum force of less than or exactly 5lbs.

In contrast the 3/4" bore pneumatic cylinder recommended by andymark has a force of about 25lbs.

Also, designing mounting brackets to interface the solenoid with the shifter will be an annoyance.

McMaster 69905K85 10w continuous duty is rated at 60 lbs.

[Captaindan]

they are definitely the way to go as far as transmissions we have gone with both methods of shifting with no problems

[cmwilson13]

pneumatic is definitely the way to go

if u go with this cylinder you also use half the air and if for some reason your pneumatic system fails it will lock you in low gear instead of in between gears

http://www.andymark.com/product-p/am-0591.htm

last year we used the super shifters with encoders and had automatic shifting using Hysteresis . it made a huge difference

[Matt H.]

Originally Posted by IndySam

McMaster 69905K85 10w continuous duty is rated at 60 lbs.

It's rated for 60 oz which is 3.75 lbs.

[Easton8]

if you're using servo shifting you robot will take a few seconds to shift, and the robot can't be moving. That takes away valuable time that you could be using to be scoring or doing other things. Pneumatic shifting is faster (takes less than a second), and you can shift while your robot is driving at full speed. Unless your team insists on not having pneumatics in your robot for some reason the pneumatic shifting is most definitely the preferable method.

[PAR_WIG1350]

Originally Posted by IndySam

McMaster 69905K85 10w continuous duty is rated at 60 lbs.

60 oz.=3.75 lbs.

Note: unlike pneumatic cylinders, the force provided by solenoids is position dependent, that is, the force changes as the solenoid actuates.

[theprgramerdude]

Pneumatic shifting broke our SuperShifters. Go with servo.

[Easton8]

Originally Posted by theprgramerdude

Pneumatic shifting broke our SuperShifters. Go with servo.

Then something was either wrong with your shifter or with the piston. In my experience and in all the teams I've talked to that have used SuperShifters none of them have ever had a problem with the pneumatic shifting. on the other hand servo shifting is slower and less reliable. Only go with servo if your robot doesn't have pneumatics.

[IndySam]

Originally Posted by theprgramerdude

Pneumatic shifting broke our SuperShifters. Go with servo.

:Smacking my forehead: doooohhhhhhhh!