Does anyone have video of the REV Linear Actuator REV-21-2735 in action. I need to show some people how fast it is, before they let me buy it.
Since it just has a hex input, you can hook it up to a gear box and change the gearing quite easily. The key from the website is 12mm of linear travel per revolution. That means it takes just 25ish revolutions to go 12 inches. If you have a standard CIM-class motor (Neo, Vortex, Kraken, etc) running at 5000 RPMs and no gearbox, it’ll go full extension in about 0.3 seconds, if I did my math right. Add a gearbox and you can get more force out of it at the cost of speed, and the multiplication for the gearing is easy at that point.
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I got that info from the site but I have people who doubt it, and want to see it in action. They feel there will need to be some limit to it. I hope to see it in action this season. Maybe we will buy one next year.
I doubt there are many videos out there, if any, at this point - it only became available for order a week ago, and I know ours only arrived Friday :). We have it set up, but haven’t actually run it yet, much less gotten it hooked up to everything on the robot so we can run it under load.
Thanks Jon, we would love to see it in action, but it does not look like we are together at any events, so far. Good luck with it, hope it lives up to its description. At this time, we are going to take a wait and see approach.
I just returned from the Canadian Pacific Regional where the team in the pit next to us, 4421 Forge Robotics, had 2 of their fail. A bolt head sheered inside the actuator. Prior to that happening, they were really thrilled with them
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We love this concept but are in the same boat hopefully some teams start posting picture and videos of it in action or even rev themselves posting some videos
This scares me - this is exactly what we are using for our hang this season.
they were using it to move their shooter up and down. They were running a pair of them, I believe. I don’t know what they were using for gear ratio
After some trials and tribulations, this was our finals’ result based on the REV Linear Actuators as the main mechanism moving our shooter, amp, and climb…
@Greg_Needel and team put together a solid piece of kit, provided you do not exceed the design parameters and even if you do, there is a built-in failure point to prevent total destruction.
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Short video of ours working. Running with a 12:1 reduction on a Neo Vortex. Ignore the poor amp shot, this was very early testing on angles 
it’s a got a great view of it moving, though!
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@mcilroyisold Thanks for shouting out 4421 on this thread!
This year I was able to help mentor Forge on the CAD and design side. One of the problems we were trying to solve early on was how to actuate our shooter mechanism. We have limited machining abilities and so I looked to a COTS component to do the job. At first many on our team were skeptical on the speed of the linear actuator so our design team ran the calcs on https://ambcalc.com/. That gave me enough confidence to give them a try.
Since design wise we tried to keep everything as simple as we could we came to the conclusion that the shooter and amp scoring mechanism could also be the mechanism we use to hang. With 2 neo vortex’s both with a 5:1 reduction on a maxplanetary gear box we are able to have plenty of power and speed to complete all of the operations we wanted. Lowering the reduction is also an option if we felt the need to extend and retract faster. A second motor was added to help with the torque required to climb in the way we do.
We found 2 “failure” points in the actuator at our last event. One being the split pin in the hex adapter, and the second being a split that happened on the lead screw where the split pin exists. The split pin failure was on us since the communication didnt go through to the programming team to create a “soft stop” in the code around the ends of the actuator. Also some magnetic limit switches never made it on the robot to ensure when the leadscrew nut reaches either end we don’t over torque the system. Lastly, the lead screw failure we had was after many hours of abusing this actuator so I wouldn’t consider it a common occurrence. The team at REV and @Greg_Needel has done a great job making a linear actuator for a team like us. The fact that the split pin failed before anything else made repairs easier to get the robot back out on the field, and the pre placed magnets on the lead screw nut combined with the 10-32 nut channels make mounting a magnetic limit switch convenient. If you want further pictures of what failed let me know and I can DM or post it here if enough people ask.
P.S. Some REV stickers would look great on the lexan beside the actuators.
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Were you able to repair these failures in the field or did they require you to replace the entire linear actuator?
Replacing the split pin requires the disassembly of the linear actuator so to ensure uptime for matches I would recommend a spare. However, our system has 2 linear actuators and we found that if one fails the other is able to continue to perform the functions in a match.
After you disassemble the actuator though it is easy to punchout the sheared split pin and replace it if you need too.
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Thanks, that video was great.
Just an FYI, we tried using Rev’s magnetic limit switches with it and got uneven results - sometimes they worked, sometimes they didn’t. We ended up going with a string potentiometer from AndyMark instead, which is giving us that control, not only for the extremes, but also set points in the middle. @Greg_Needel it would be really nice to have a magnetic limit switch that mounted better to this. The one you guys have has mounting spacing that doesn’t match the linear actuator extrusion, and the sensors are on the wrong sides to make it easy to mount. Something that we can just slide in a couple of nuts and bolt down would be really nice! It would be even more awesome if there were tapped mount holes for the bottom/top extreme, or some way to easily locate the limit switch (maybe something like the wheel alignment tools for MAXSwerve?) to ensure your soft endpoints were set in the correct spots.
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We were working on a custom solution for the linear actuator but it didn’t get done in time. It will be something we will be launching in the future.
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