Chief Delphi - What motors are you using for your lift?

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Re: What motors are you using for your lift?

One CIM on an 8.45:1 gearbox (same as on the KOP for interchangeability), geared down 32:15 by chain, then lifting using two #35 chains on 15 tooth sprockets. It has several times the lifting power we'll need, because we're going to try it without a brake. We're only using three CIMs for drive, so we are going to check the current draw when we hold the maximum load (4 totes) and add another CIM if it's much over 20A, or if we experience too much heating during practice. On the curves it looks like it'll be about 14A, which means about 170W, all going to heat when holding station on four totes. I really suspect that we are going to build a brake on Thursday and Saturday.

Quote:

Originally Posted by Oblarg (Post 1441083)

Overkill, but a little overkill never hurt anyone.

An ironic choice of phrase :)

Re: What motors are you using for your lift?

We are using 1 mini-CIM connected to a 35:1 versaplanetary with a 15T sprocket driving a #35 chain to our elevator carriage. It seems to have the power and speed we were looking for.

Re: What motors are you using for your lift?

2 gearboxes, each with a CIM in a Banebots planetary with a 16:1 reduction. It lifts at a speed that satisfies us and can easily lift 6 totes and a container.

Re: What motors are you using for your lift?

Two CIMs into a standard ratio AndyMark RAW Box on a 15T #35 sprocket (PD = 1.79").

Re: What motors are you using for your lift?

Two CIMs in a 12.75:1 toughbox.

We did the math on one CIM and decided we liked two better.

Re: What motors are you using for your lift?

Our team is using a threaded rod setup.

We used two mini-CIMs on a Toughbox-Mini gearbox. It's more than enough for that particular purpose: we can lift six totes and a bin with no trouble.

Re: What motors are you using for your lift?

We are using a single Bag motor and some weight compensation trickery. It seems pretty unique compared to everyone else's specs, but it fits our strategy very well. We'll see.

Re: What motors are you using for your lift?

Quote:

Originally Posted by GeeTwo (Post 1441145)

On the curves it looks like it'll be about 14A, which means about 170W, all going to heat when holding...

14A @ 0 RPM is more like 18W.

Re: What motors are you using for your lift?

Quote:

Originally Posted by Mr V (Post 1441128)

The gear ratio needed depends on what is happening after the transmission. What is the diameter of the drum or drive sprocket?

Define what you mean by lift 6 totes plus 1 bin in 3-4 sec, how far do you want to lift it in that time? Once you have created a 6T + 1C stack you only need to lift it a little more than 2" to place it on the scoring platform. That should be able to be done in a fraction of a second. So how are you creating that stack, ie what is the heaviest load and how far to you need to lift it and what is the highest distance you need to lift and how much is that weight.

Here is the JVN design calculator page. http://www.chiefdelphi.com/media/papers/2755? On the first tab copy the motor you wish to use and paste it into the linear motion tab motor fields.

You can then select the motors per trans, gear box efficiency (I use 10% per planetary stage), the amount of weight you wish to lift (don't forget the weight of the mechanism and a fudge factor to overcome the friction), the distance you want to lift the load and then play with gear ratios. For the planetary it is easiest to put 1 in for the drive and the ratio of the stage in the driven fields. For stages you are not using just put 1 in both fields. It is a good idea to make sure that the stall torque is significantly more than the load you want to lift in case the load "sticks". Personally I wouldn't design for less than 2X the actual weight.

Personally I'd recommend the Mini CIM or CIM for this application despite that it is more involved to mount. The 775 is a fan cooled motor so it doesn't like spinning slowly and really doesn't like being stalled. The CIM families on the other hand are much more tolerant of operating at slow speeds and being stalled.

Agree!
We use a CIM motor last year for our winch and it performed well and tolerate stalling very well. The load we put on last year is way higher than this year's lift requirement. We did fried one CIM motor on our practice bot but that was only after practicing for 3 hours non stop. The motor was so hot we could fry an egg.
We use the JVN calculator to decide on the sprocket size and versaplanetary gear ratio for this year's lift. What we observe in real life is very close to what we predicted.

Re: What motors are you using for your lift?

We're using 2 CIMs and a Mini-CIM with a 16.73:1 reduction

Re: What motors are you using for your lift?

Two RS775's, each powering a 50:1 Versaplanetary gearbox with a disc brake coupled inbetween the two gearboxes. A video of it can be found here: http://youtu.be/JrebWdH8x4c

Re: What motors are you using for your lift?

mini-CIM to 20:1 versaplanetary. seems to be as fast as we want and lifts fine. will be beginning PID testing in the next day or so to see how it handles the load. Hoping to not need a break.

Re: What motors are you using for your lift?

I can't believe only one other person has mentioned BAG motors. In my opinion, they are the perfect choice for this application, as they have a similar free speed as the 775s and can interface perfectly with the VersaPlanetaries. Also, they aren't fan cooled and instead have a high thermal density, meaning they won't get wrecked as you PID loops try to hold the totes in place. They've been champs for us, and they weight only a fraction of a CIM or miniCIM.

Re: What motors are you using for your lift?

The BAG motor might be ok for some lifts, but if there's a CIM or miniCIM available, why not overpower the mechanism? speed is good....power is good....extra capacity is good....