One CIM, 1:25 versaplanetary gear box driving 15t sprocket chain system. Measured speed 1.3 feet per second. PID with 3 totes. Holding current about 8 amps using a clamp meter. About 25 amp at full speed with 3 totes. Our arm system is 22 pounds. No constant spring.
Our lift mechanism originally used 2 CIMS one on each side through a 2 stage gearbox on each side. Due to weight issues, we swapped them out with 775 banebots with the CIMulator adaptor.
We saved 2 and 1/2 pounds and they easily lift the elevator with 6 totes with a trash can.
When we had the CIMS on, there were overkill, but only decided to swap out due to weight issues.
We ended up using a cim for ours, geared 12:1 to the elevator via versaplanetary. We can switch to two if we need to or lower the gear ratio.
Is there any good way to mount the VersaPlanetary Dual Motor Input? There are the two screw holes on the panetary gear box but I feel that would be too much weight only on two.
Yes, the Taigene’s stall torque is 360 lb-in and the window motor’s (Denso) is 93.8 lb-in.
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. Paper: JVN's Mechanical Design Calculator 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.
We are using 2 snowblower motors direct driving opposite ends of a shaft with a pulley fixed in the center. It is essentially a winch. We only need to lift 2 totes max. at a time.
FRC558 is running a custom 18:1 worm gearbox with dual mini CIM input and for now a 4" diameter drum.
Two CIMs on the lift. Jumping on the six CIM hype train here.
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.
An ironic choice of phrase
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.
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.
Two CIMs into a standard ratio AndyMark RAW Box on a 15T #35 sprocket (PD = 1.79").
Two CIMs in a 12.75:1 toughbox.
We did the math on one CIM and decided we liked two better.
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.
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.
14A @ 0 RPM is more like 18W.
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.
We’re using 2 CIMs and a Mini-CIM with a 16.73:1 reduction