DART Linear Actuators for the CIM Motor
 

The folks at iR3 Creative Engineering are excited to announce a new line of products called DART Linear Actuators, linear actuators developed specifically around the CIM motor.

DART Linear Actuators were optimized to be used by FIRST robotics Teams. The DART's packaging offers 3 gear ratios, 1:1, 2:1 and 2.5:1 and comes in 2 stroke lengths 6" and 12". The DART actuators utilize a precision lead screw assembly which can offer position control over it's range of motion, something that FRC pneumatic systems struggle to achieve. The DART Actuators are both strong AND fast providing forces greater than 200lbs or speeds over 12 in/s.

The DART Linear Actuators will be distributed by AndyMark.com and will be available in time for the 2015 build season! We will be updating the website with more information in the coming weeks and we're hoping that this new product will help FRC teams in the seasons to come.

For more information, videos and CAD files please visit: DARTActuators.com

Or if you just want to skip to our announcement video click here: http://youtu.be/bh2c5Aqmqc0

Re: DART Linear Actuators for the CIM Motor
 

Revolutionary.

I can see these used all over the place even with smaller motors using a CIMile or versaPlanetary.

A great COTS linear actuator for us to use.

Re: DART Linear Actuators for the CIM Motor
 

Wow! This looks like it could be really useful. Will definitely keep this in mind when brainstorming this year.

Re: DART Linear Actuators for the CIM Motor
 

That looks pretty awesome.

One question though... will the actuator backdrive? Using the arm in the video as an example, when you put the arm up, can you just turn off the motor off and the arm will stay in position, or do you need to power the motor to some amount to keep it there?

I think I know the answer, but want to make sure as it's not specified in the video or website :)

Re: DART Linear Actuators for the CIM Motor
 

Generally, we did not see back-drive with the actuators during testing. Technically, because the screw offers greater than 50% efficiency it is not considered self locking and may back-drive especially under high load and high vibration. That said, the additional resistance of the the motor and gear system limits the screw from back-driving.

During our testing the screw did not back-drive under the calculated loads and in many different configurations including the arm in the video.

Re: DART Linear Actuators for the CIM Motor
 

Dear iR3,

Is there a range of prices that you anticipate the DART linear actuator will fall in?

Re: DART Linear Actuators for the CIM Motor
 

When will teams be able to get their hand on them?

Re: DART Linear Actuators for the CIM Motor
 

!

Depending on the game, I was planning on making an adapter to join one of these actuators with an FRC legal motor. Depending on your price, you may save us a lot of engineering.
http://www.princessauto.com/en/detai...or/A-p8272551e

Team 4557 used linear actuators two years ago (our rookie year) we swapped the motors for legal motors, but these would have saved some hair pulling

Re: DART Linear Actuators for the CIM Motor
 

Do you anticipate having enough product to support teams if this game lends itself to your actutator?

These look cool! How much money do you plan to sell these for?

Re: DART Linear Actuators for the CIM Motor
 

I am very interested. I'll be watching AndyMark to see these for sale.

Re: DART Linear Actuators for the CIM Motor
 

We will certainly do our best to meet market demand. AndyMark will have a sizable inventory to start the season and we will have many of the components on hand if demand is higher than expected.

We agree! This is actually one of the places we started. We looked at the actuator you linked along with larger alternatives like this one which is built to handle a more comparable motor power density to the CIM.

For reasons of weight, speed, packaging, etc. we decided we needed a ground up solution for FRC. We wanted to target a faster, lighter assembly for these applications. In our research, we found that one of the common complaints in regards to linear actuators is that they are slow and we wanted to break that mold with this product.

We wanted to land on something that could provide the force of a 2" bore pneumatic actuator at 60 psi AND still have enough speed to allow bots to be competitive.

The DART Linear Actuators will be introduced at around $380.

Re: DART Linear Actuators for the CIM Motor
 

This is the closest thing FRC has ever had to a single piece, COTS solution for controlling a long robot arm. This is a huge development and a really cool product. I wouldn't be surprised to see one of these on a 2791 robot next season!

Re: DART Linear Actuators for the CIM Motor
 

How much does it weigh without the CIM motor?

Re: DART Linear Actuators for the CIM Motor
 

What's the repeatable accuracy of this actuator in inches?

Re: DART Linear Actuators for the CIM Motor
 

I would imagine it is the repeatable accuracy of the potentiometer, which depending on the type/implementation, will be a number significantly less than 1.

Re: DART Linear Actuators for the CIM Motor
 

I think a more appropriate question is how much end play is there in each direction under load. I.E., how much backlash does the geartrain have. Of course, if you always put it in compression is isn't that much of an issue.

Re: DART Linear Actuators for the CIM Motor
 

Lash in the potentiometer gear mesh will also be a factor in repeatability, with the ones mentioned in the preceding posts. Of course, lash/play in the mechanism powered by this actuator will be (at least) equally important.

Can someone involved in making the demonstration arm shown in the linked video please measure and post the unpowered vertical play at the end of the arm? I think tape measure accuracy would be enough to give us all a good idea of what to expect.

Re: DART Linear Actuators for the CIM Motor
 

A fully laden 12" Stroke Length, that's including the pot, CIM and limit switches it's 5.8. According to AndyMark the CIM is 2.8lbs so that would put the DART at 3lbs.

Re: DART Linear Actuators for the CIM Motor
 

You are correct, there will be the backlash in the POT gears, pulleys and screw. You also need to take into account the bit rate of the controller as well if being driven by position commands via feedback from the pot.

We will set up a test to measure the unpowered vertical play in that or similar assembly in the coming week.

Re: DART Linear Actuators for the CIM Motor
 

Dan,

Cool product and it looks great.

I do have a question: what is the actual pitch, or lead, of the linear actuator itself?

You gave us the gear ratio (that can be changed ... cool) but having the pitch is a crucial piece of information that many users may not realize they need.

mm/rev, in/rev, mm/deg, mm/rev or whatever units suit your fancy would be appreciated.

Thanks,
Paul

Re: DART Linear Actuators for the CIM Motor
 

Yow!, why so much?... well, let me know if the price comes down... otherwise I think for me personally it will be more benefit to make them from other cheaper parts. I know I can find good deals on lead screws for around 12-15 dollars.

Re: DART Linear Actuators for the CIM Motor
 

I'm thinking it is priced there because it is a good combination of power and speed. The two other similar products linked here and here are both a fraction of the speed that the DART is offering. I'm also guessing that the DART is going to be easier (legal?) to modify, thus giving you much better control of efficiency.

Re: DART Linear Actuators for the CIM Motor
 

It appears that you're using a normal 3/8" ball bearing to take all the thrust loads from the lead screw. How does this bearing hold up to large impacts and high loading? I only ask because our team has seen issues with bearings falling apart due to high thrust loads.

Re: DART Linear Actuators for the CIM Motor
 

As for modifying, consider that any motor or transmission with a cim shaft output can drive this. If these turn out to be robust (per the question about how the thrust load is handled) then it's pretty neat what you can do with it with COT's components. Utilizing versa planetaries will result in just about any speed you can imagine.

Re: DART Linear Actuators for the CIM Motor
 

Thanks for the kind words Paul. The lead screw has a .500" O.D. and a .200" Lead. This information hadn't made it's way to the website but we've since added it and a calculator to help you determine Forces and Speeds for a custom configuration.


We're dedicated to producing affordable components for all FRC teams and we will continue to look for ways to improve our design and manufacturing processes to help bring the cost down. As Monochron pointed out, this ground up solution will bring a competitive advantage over other comparable linear actuators. Our actuator is also less expensive than many of the other industry alternatives that allow for similar power density.

We iterated on the design and selection of bearings in the design process and landed on a high load capacity ball bearing that has performed well in testing. We have safely operated the linear at greater than 300lbs with no damage.

That said, with significant constant load increases there will be decreased bearing life and at some point they may need to be replaced. Since we were focused primarily on the CIM at higher speeds and forces less than 250 lbs I'd like to do some work here to determine what kind of load/life combos we could see.

Re: DART Linear Actuators for the CIM Motor
 

I guess everyone has different needs ours is affordability probably under 100 dollars and it doesn't need all the bells and whistles offered on the high end product. I'm not sure if there are others that would like to save money, but if there are... perhaps there is a dialed down version... that might not offer as much force, but could be made with cheaper parts for a cheaper price. I plan on having some solution in the near future on a side project I'm working on.

There is another thread of similar nature that you may wish to check out here: http://www.chiefdelphi.com/forums/sh...93#post1397193

Re: DART Linear Actuators for the CIM Motor
 

Any news on when these will be available on AndyMark?

Re: DART Linear Actuators for the CIM Motor
 

The pages are up now and being populated with the technical bits. The DARTs should be available late this week/early next week at AM. The quickest way to get updates will be to select "Email Me When Available".

http://www.andymark.com/SearchResults.asp?Search=dart

Thanks,

Dan R.

Re: DART Linear Actuators for the CIM Motor
 

While waiting for the DART actuators to become available on AndyMark, I was wondering if the other two actuators mentioned in this thread (http://www.princessauto.com/en/detai...or/A-p8272551e & https://www.servocity.com/html/560_l...ml#.VJcpBV4BNo) perform equally well as the AndyMark one and if they are legal according to the rules. If not, are there any modifications that need to be brought to the non-AndyMark actuators to make them legal? Thanks!

Re: DART Linear Actuators for the CIM Motor
 

See R18.

Re: DART Linear Actuators for the CIM Motor
 

OK, so we would have to change the motor ... it's going to be possible, right? And is that all?

Re: DART Linear Actuators for the CIM Motor
 

And does anyone have experience with these two actuators?

Re: DART Linear Actuators for the CIM Motor
 

If you're planning to buy a different COTS electric cylinder and swap out the motor, you might also consider Bimba's offerings (you'll need to machine or print? an adaptor):

http://www.bimba.com/Products-and-Ca...tric-Actuator/

I can't guarantee these actuators will work well with CIMS. DART would have saved a lot of R&D, were they available.

Re: DART Linear Actuators for the CIM Motor
 

OK, so I guess that we should just put the actuators aside for now and concentrate on other parts of the robot. And then when they become available again on AndyMark, we'll get back to them. Thanks!

Re: DART Linear Actuators for the CIM Motor
 

Thanks for the interest. We apologize for the delay as we had a slip in deliveries from some of our suppliers. The first shipment of DARTs is at AndyMark now and available for purchase. You can place your order here:

http://www.andymark.com/DART-s/540.htm

They will receive a second shipment on Wednesday, 1/14 and a Third 1/21.

AndyMark has been a great partner on this and the unfortunate slip in availability was on our end. We have a plan in place and hope to be able to keep up with demand.

Re: DART Linear Actuators for the CIM Motor
 

I may be missing something here, please help me understand what I am missing. Question is "Are they legal on the 2015 FRC Robot?" Are they an actuator? Answer: YES. They are sold as a "DART actuator kit(s)", under the AndyMark Category of "ACTUATORS." w/ AM Part #'s in 2 different lengths.

I know Ri3D "Toat Ma Goat" used (at least), 3 of them on their Ri3D Robot (2 on the 4 bar lift, and 1 on that "magic" wheeled intake mechanism, and I see many smooth uses for them over the choice of pneumatics this year for really smooth control (and no backdrive), though limited in the allowable CIMs total, so a reasonable tradeoff in the drive motor choices...slow go & fine control is better this year anyway). I also suspect that robot will never actually be FIRST Competition Inspected...Am I wrong there?

I go to R18 and the title is "4.7 Motors & Actuators
R18 The only motors and actuators permitted on 2015 FRC ROBOTS include the following:" (Bold, Italics, Underline....mine).

Then I go to AndyMark as directed and the 2 Model #'s for the Dart Linear Actuators (both models), are AM-3072 & AM-3076. Neither are listed in R-18 of the 2015 FRC Robot allowable Motors & Actuators list that I can see listed in the box. (Logically, if it is a "motor or actuator," COTS or not, and it isn't in that list, we can't use it on our 2015 Robots).

I understand the CIMS attached in the pic (but are sold separately, as seen in the assembly instruction docs), would be legal as they are listed. True also, that it is not considered an "Electrical solenoid actuator(s)." So the lower in the box of R18 listed "actuators," does not apply. (If it did we'd all be in trouble since definitely more than 1" Stroke on both).
___________________________
Are they 2015 FRC Robot legal or not under R18? (What am I missing here folks?) I do not want to offhand say they are not legal, and people appear to be ordering them (second shipment due in 1/15/2015)...But I cannot find them there...And the key words that get me are right there in the R18 Title.

R18 "The only motors and actuators permitted on 2015 FRC ROBOTS include.....".

I like em', and I want to see iR3 Creative (Dart) sell a bunch (though I agree w/ some, $380.00 without motors is hefty compared to other choices that others linked to, though those would need to be adapted, and if Darts are not legal, neither would the others be if both are sold as Actuators, no matter the motor attached)...It is sold as an actuator or it isn't, and it's legal or it isn't. The recent Q&A question/answer was very specific....But it didn't say the Dart actuators are legal either...It just reitterated the, If it isn't an "Electrical solenoid actuator" in line with what is printed in the box under R18...It isn't legal" line.

I don't even think Q&A is going to answer the question of "Are the Dart Actuators being sold as AM-3072 & AM-3076 legal on the FRC 2015 Robot?" (outside of the "if it isn't listed in R18, it isn't legal" type answer).

I'd sure hate to see what comes down after numerous purchases across our community at nearly $400.00 a pop each if they are later...Never Mind...I don't even want to go there...I hope I am blind and just not seeing something that is really listed in that box, or there is some unwritten rule I'm missing, because it is sold as "a kit" and we are considered "fabricating by assembling" & attaching a legal motor to an actuator that makes it legal or something...HELP PLEASE?

Am I just "lawyering" R18? (Still learning the design & materials choice phase here). Yes...A pneumatic cylinder is also an actuator, but it isn't electric....I'll just shut up here.....Lol. (Cough!):yikes: :ahh:

Re: DART Linear Actuators for the CIM Motor
 

Dan....Please don't take the above as unkind words in any way, I come to CD to learn. If they are COTS, and they are legal this year, then I just expected them to be on the R18 list, as I would the Bimba ones (with the proper motors of course). Beyond the fact that I like them.

And if they are allowed, I certainly hope you sell a ton of them as it is always great to see sucessful American mfg. businesses these days.

Re: DART Linear Actuators for the CIM Motor
 

They ARE legal. As follows:

1) They are a COTS item (which are allowed unless specifically restricted).
2) They do not use an illegal motor.
3) They do not meet any other criteria for being illegal that I can find.

Trust me, if the only actuators we were allowed to use were the ones in the table, I could make a pretty darn good argument that pneumatic cylinders and gearboxes were also illegal--after all, both actuate something!

Try thinking of them as a gearbox that provides linear motion instead of rotary motion.

Re: DART Linear Actuators for the CIM Motor
 

They are permitted.... The game manual separates actuators from motors... Though I would expect the CIMs on the Dart actuators to count against the six...... I purchased a pair of the six inch actuators tonight.

Re: DART Linear Actuators for the CIM Motor
 

Thanks guys. Like I said...still learning. (SIMS are COTS items also), but are listed...I expected to find them on the list too (or at least see the highlighted words added to R18).

R18 The only motors and Electrical solenoid actuators permitted on 2015 FRC ROBOTS include the following: Or, a line added at the bottom of Table 4-1 like "Motor Driven Actuators allowed if supplied and/or fitted w/ a motor listed in Table 4-1: Legal Motors above." Limited (see motor limits above).

And, the answer to someones question in the Q&A I read today, really confused me about these particular Actuators.

So all 3 of the others in the thread are cots items also...But, Dart has the 2 lengths 6" & 12" whipped because they need no adapting whatsoever to install your CIM and just go. Smooth.

Thanks again.

Re: DART Linear Actuators for the CIM Motor
 

Thanks for the concern, it's always good to talk through the questions.

They are legal and you are able to use more than just the CIM motors on them. Mini - CIMs, Versa Planetaries and the AM Planetaries all plug into the DART to give you a wide range of motor options. The Ri3D 1.0 intake used a Bag motor and Versa planetary to drive.

I think what's hanging you up is the word "actuator," which is how linears are typically described. The DART by itself boils down to a packaged gearbox and lead screw. It is designed to use FIRST legal motors. It is a unique way to convert the rotary motion of a FIRST legal motor to linear motion through a mechanical device. It doesn't become an actuator until you attach one of the FIRST legal motors to it as is with all COTs gearbox solutions.

I believe the original question was not whether the DARTs are legal but if other off the shelf actuators could be modified to be legal. Teams have done this for years without issue. To do so, you need to find a product that has a solution for a similar power density to the motor you are trying to use and adapt a FIRST legal motor. The modified linear solutions must also comply with the other COTs definitions.

Lead screws have been used for years in FIRST and are even offered in FIRST choice. The DART simply offers an efficient and engineered solution to package them.

Re: DART Linear Actuators for the CIM Motor
 

Dan,

I am more confused now than I was yesterday....I just read the FRC First Q&A Question(s) Q3 and a follow up Question of Q38 (Go to Q38 as both are linked there).

Just so you know, I did not ask the questions, a single team asked both questions. (I asked only here).

I cannot link them here, but, The (Q3) Original question was: Q. Are we allowed to use electric actuators that are not solenoid actuators? (1 follow-Up Questions) FRC4913 on 1-7-2015.

A. Electric actuators permitted for 2015 are listed in Table 4-1. The row that permits electric solenoid actuators allows any product that meets the listed specifications and is sold as an electric solenoid actuator. Published by GDC

Then...The (Q38) follow up question was the one that stumped me Huge.

Q. Thank You. But some electric actuators are NOT solenoid actuators (based on screw drived motion). Are they allowed in any size? Table 4-1 is not forbidding these. FRC4913 on 1-7-2015.

A. No, R18 specifies that "The only motors and actuators permitted on the 2015 FRC ROBOTS include" those listed in Table 4-1.
Electric actuators that are not solenoid actuators are not listed in Table 4-1 and are therefore not legal. Published by GDC

__________________________________________________ ______
Can you see now where I am totally confused folks? Please do not hate the messenger, Ok Dan?

They asked the question in a very specific way (used the word "drived" instead of driven), but enough detailed info to receive that straight answer.

If I were a seller or a buyer I'd be a bit concerned. (I was just looking as interest and attempting to look at them for something as a use outside of FRC actually, but then thought about use this year inside of FIRST FRC after seeing them used). The original Q3 bothered me, the Q38 really confused the crap out of me! And it still does.

I fully agree that it is just a gearbox. Somebody else though does not seem to agree, and they make the rules, I simply don't. (Maybe there is just a misunderstanding however). I also agree that the word "actuators" encompasses a ton of items that would be disallowed if all actuators, except electric solenoid actuators, were disallowed.

Good Luck my friend. (I hope AM and someone @ FIRST can help you with that).

Re: DART Linear Actuators for the CIM Motor
 

Dan what is the thread pitch on the rod end of the actuator? we have a couple on order but Andy didn't know. Id like to order the rod ends so when the actuators show up i can get them functioning asap

Re: DART Linear Actuators for the CIM Motor
 

5/16" - 24 on both ends.

The clevis also has a 5/16" through hole.

Re: DART Linear Actuators for the CIM Motor
 

What you are missing is the the DART Linear Actuator is simply a linear motion mechanism when there aren't any motors on them. From a legality standpoint, they are no different from any of the rotary motion gearboxes sold and used today in FRC.

It only becomes an "Actuator" when a motor is attached to it. If you attach FRC legal motors (Like the BAG with Versaplanetary in their video) then this device is perfectly legal.

Re: DART Linear Actuators for the CIM Motor
 

Are there any 2d cads for this and are there any dwg files for the 12 inch dart actuator?:confused: