Linear Actuators?
 

Hey guys I was thinking that FIRST should make DC linear actuators legal on FRC robots. I can see the need for them, especially if you dont want to use pneumatics. I understand that pneumatics are a faster, more powerful method, but these are less complicated. What do you guys think?

Re: Linear Actuators?
 

Sounds like an interesting idea. However, I did notice you've already posted this thread a few minutes ago. I see you're new, don't worry man, it's cool. Just a heads up for the future, double posting is frowned upon, as it splits up the useful responses to more than one thread.

Back to the topic...

What kind of linear actuators are you thinking of? (model?) I haven't looked into them much, but it seems they would be a pretty cool way to replace pneumatics.

Re: Linear Actuators?
 

Hey sorry about the double posting but i put it in technical discussions at first and i meant to put it in motors.

Anyways, i was thinking maybe some firgelli or pi brand actuators.

Re: Linear Actuators?
 

Muscle wire (Nitinol/SMA) would be cool for light duty applications. It would be lighter than either pneumatics or servos and would be perfect for releasing latches that keep the robot in starting configuration. Adding a pneumatics system just for that would be a terrible use of weight and space, and in some situations, so would servos or solenoids. SMA actuators take up no more space than a piece of fishing line, require very little additional hardware, are easy to integrate even if they are not accounted for in the design, and weigh next to nothing.

Re: Linear Actuators?
 

I see nothing in the rules that would preclude the use of muscle wire currently. We've toyed around with it but haven't found an application where it's better than a servo in FRC. It might happen though.

Re: Linear Actuators?
 

I was also going to mention artificial muscle, but Ive not heard of this muscle wire. Is it artificial muscle, or is it closer to the wires used to actuate bicycle brakes?

Re: Linear Actuators?
 

SMA or muscle wire isn't like a bike cable. It's wire that remembers it's shape and returns to that shape by heating (usually through electric current) http://en.wikipedia.org/wiki/Shape-memory_alloy. A couple of videos http://www.youtube.com/watch?v=k9f-W6Xi_Wo and http://www.youtube.com/watch?feature...&v=Mh31B4Ryn9U

Re: Linear Actuators?
 

Ya know... There hasn't been anything in the rules about linear actuators being illegal.

However, the integral motors used to power them have been illegal. So, it's perfectly legitimate to build a linear actuator with a KOP motor--or remove the motor from a COTS linear actuator and replace it with a legal motor. Just make sure that if you go the latter route, you have documentation.

Also, look up "leadscrew".


Of course, I don't know the 2013 rules yet, so maybe there will be an allowance for said actuators.

Re: Linear Actuators?
 

Please see R48 listing the only legal motors, servos and solenoids. There is no provisions for muscle wire. You may however use a similar product that is pneumatically operated and was supplied in the KOP last year.