Animatic Servos

[CRAFTY]

Does anone have experience with Animatics products???

Thanks.

[unterhaus]

lots and lots of lawyers? I fail to understand why putting two things in one box warrants a patent, but that's just the way I am.

They look ok, depending on how much power you drive through them, there may be an issue with integrated amp/motor combinations. Lots of servo drive applications have nearly no power going through them on an average basis.

If you are buying them used, I would check to see if there are any gotchas, such as software you must buy. Also, do they meet your power requirements, can you get the connectors you need. There are all sorts of reasons why such a motor may be on the surplus market, some of which are no good for you.

[CRAFTY]

Thanks For The Reply. Actually I Was Thinking Of Buying All New Stuff. I Just Don't Know Anybody Using Them. I Did Get A Hold Of The Software Drivr Demo, Seems Pretty Good But I Have Had Better.
Thanks Again For The Reply.

[mcpltd]

We used to distribute for them, and they are a good product but found them very expensive.
but that was most likely becasue no other company in the US was offering a integratedd solution then.
There are not quite few outside the US offering intergrated solutions, but not within the US because of the problems on the legal front, so i guess they are still quite costly.
It may be better to look at Elmo, they are supported all over the world, and have a fantastic product range. (At a good price)

[unterhaus]

I don't know what has happened, but it seems there are a couple of other companies selling integrated motors in the U.S. I'll check out Elmo, I am looking for something like this.

Does Elmo have an integrated drive/motor? I see the Whistle-Ocarina on their site, but I don't see any motors with that interface.

[JFettig]

A friend of mine works for company who makes robots and machines and they use them often and like them.
he claims that they could be used for a cnc, but as I understand him it would exactly work that well like that without a whole new controller.

Jon

[Mariss Freimanis]

Let's see. We have a motor that gets hot when it's producing power. We also have a motor drive that gets hot when it's producing power. I know; let's put the two together!

If the motor burns up, you're out of a drive; if the drive burns up, you're out of a motor. Both would do better seperated and on a heatsink.

What benefit do you gain by putting the two together? You can also mix anchovies and ice-cream together but why would you want to? The concept has never made any sense to me other than it looks cool.

Mariss

[unterhaus]

Mariss, in most cases, I'm with you on this, I'm interested in them for making a robotic arm like the one on the iRobot EOD packbot. I have limited room for electronics, and I want to limit the number of wires involved. And the packaging is easy, which is a big benefit considering I have a very limited amount of time to work on the project.

Animatics might not be the best way to go about it, today I was looking at some of the AMC drives where it looks like I may be able to put the drive in a very small space near the motor. With those, I could use the arm structure itself as a heatsink.

[Mariss Freimanis]

Unterhaus,

I tend to look at things as an engineer. To me as an engineer, the concept is all wrong no matter the brand (good thing I don't have strong opinions about matters).

We were approached about 9 to 12 months ago by a major company involved in integrated motor-drives about designing a Gecko to fit as an integrated drive on NEMA-23 and NEMA-34 motors.

I did a feasibilty study of the project to see if we would be interested.

The surface-area of the back of a NEMA-23 is larger than the area of our printed circuit board, so there was no question of a re-arranged Gecko fitting on the back of the motor. What became breath-taking was the thermal budget of the motor/drive combination.

A reasonable case temperature for a motor giving its money's worth to you is 85C. Because the integral drive for all practical purposes is thermally coupled to the motor, it has 85C as its ambient temperature. This is before the drive dissipates a single Watt!

Thermal conductivity to ambient (25C) is essentially nil. There are no thermal radiators anywhere (read heatsink with fins). The only thermal path is to the motor which is (a) already sitting at 85C and (b) has a very high thermal resistance because I see no fins on it.

Net result: The drive has to be so de-rated it's a crime. Very expensive, grossly over-rated power devices have to be used to keep the miserly thermal budget 'in balance'. A crappy 2A motor has to have a drive (given even minimal heatsinking) that would be good for 10A. You get 2A, you pay for 10A.

The idiocy of the whole proposition is for what reason? What do you gain for these very severe comprimises? Nothing I could discern.

You mentioned severe space constraints. The misfortunate drive on the back of the motor occupies 'x' number of cubic inches. Those same number of cubic inches could be occupied elswhere (like remote from the motor and on a heatsink delivering far more power to the remote motor). It's a matter of re-distributing volume from where it doesn't belong to where it does.

Some ideas are value-driven, others are marketing-driven. I'll bet it was some sales-type that had the light bulb turn on over his head and caused him to say "Wouldn't it be cool to have a drive integrated with a motor in one package!" Only a sales-type would be stupid enough to come up with the idea and only a sales-type would promote the idea to where it is today instead of letting it die a richly-deserved death.

Otherwise I have no opinions on the matter except to say we declined the proposal for reasons mentioned.

Mariss

[unterhaus]

I think it probably makes more sense on a servo. You can drive a stepper w/ 4 wires, so you are losing on wires. And your point on the temps is well taken.

The calculations on a servo are much different. You are getting rid of at least 10 wires per motor, and the cables that remain are much simpler. I think that the temps are going to be a lot lower too. I have brushless servos that basically are holding most of the day, and they are at ambient. In my application, average power is low, so I think that I'd be ok. I have never considered them in the past, but this seems like a special case where they would have a lot of advantages.

The cheapest arm I've found so far was $68000. iRobot really isn't interested in selling us their arm for our application.

[Mariss Freimanis]

None the less I think it is a waste of resources to have to grossly under-rate a drive only so that it can function in what I believe is a pointlessly constrained enviroment.

It may save a few wire-runs but at what expense?

Mariss

[unterhaus]

On this arm, there are 5 remote motors. If I go brushless for the weight, torque, and speed advantages, that's a minimum of 12 wires per motor. That's hardly a few wires, the wire management suddenly dominates the design, and forces me to go to steppers, which I don't want to do.

With a remote drive, you can daisy chain the control and power. I haven't checked what the minimum number of wires would be, but just going to one power pair instead of 15 is going to save some significant bulk.