Re: SD540 Motor Controller
 

full FRC weight (154lbs with bumpers and battery) plaction (or similar) wheels at around 10fps. That's about the worse I've seen at a competition. A test both with and without fans would also be interesting if you don't mind.

Re: SD540 Motor Controller
 

That sounds more realistic.

Do you have a way to monitor or measure the temperature of the heatsinks?

Re: SD540 Motor Controller
 

Do you have a protocol for this?

Re: SD540 Motor Controller
 

Does it really matter if it has bumpers if it is the proper weight?

I have 4", 6" and 8" AndyMark plaction wheels: I assume 4"?
I'll likely stick with the keyed shafts as I only have a limited amount of hex shaft and bearings.
What distance between the wheels (frame dimension)?
What configuration of the wheels: center drop with 6 wheels all driven with chain?

Fans are no problem I have fans and a CFM meter somewhere.

I have a lot of ways I can measure and log temperature.
What sort of resolution are you after?

Anyone care if a cRIO is used as the control system for this test?
I'll use the FRC approved master breaker and the FRC PDB that came with the cRIO if I do that.

Re: SD540 Motor Controller
 

He was just saying that 154lbs is the actual max FRC Robot weight. Some people might think they should test at 120lbs since that is the weight limit but they would be forgetting the 34lbs from bumpers and battery.

Re: SD540 Motor Controller
 

I've got plenty of exercise weights I can toss on there.

Re: SD540 Motor Controller
 

Most safety standards state that parts that can be touched (i.e. the heatsink) should remain below 65 to 75 degrees C. With approximately a 25 degree C ambient temperature, those numbers will also leave plenty of thermal margin for most electronic parts such that their lifetime is acceptable (in the range of years).

One would want to see the temperature stabilize for some reasonable period of time. Considering the small thermal mass of the heatsink on this controller, a 2-3 degree range over 5 minutes seems reasonable. It certainly should not still be showing an upward trend as in the data published by Mindsensors. In our lab at work, we stop the tests after there is less than 1 degree C of variation over an hour but that is not realistic here with a robot that is constantly in motion and a load that is not held constant.

Re: SD540 Motor Controller
 

Is there any data on all this floating around somewhere for existing motor controllers? Obviously, we know that the existing victors and talons work fine, but it would be interesting to see the data from the new controllers compared to an existing one rather than seeing numbers thrown out without any intuitive scale.

Re: SD540 Motor Controller
 

Single stage and single CIM AndyMark Stackerbox with a 3.57:1 ratio feeding a 12 tooth double sprocket which is #35 chain driving a 26 tooth sprocket on the AndyMark 4" plaction tires. Arranged as a 6 wheel center drop with the gear box on one end and the other end driving 1:1 off the center axle. Sounds like that's just over 10.1fps to me but I am pretty tired right now.

That meet your expectations?

I've got the double sprockets and the #35 chain with link kits.
I've got 10 single stage Stackerboxes.
I -may- have some 26 tooth sprockets on some used tires if not I'll need to order those.
I've got some sprocket spacers for the AndyMark tires.

Re: SD540 Motor Controller
 

If you really want to go overboard on these controllers go 4 wheel, your choice. Otherwise looks absolutely fine to me. Realistically there will be more variance in "aggressive" driving than from any individual design choice.

Re: SD540 Motor Controller
 

To be clear, since I described one side of a potential drive train, when you proposed going even further with 4 wheel you would end up with a robot with 8 wheels total. 4 on the floor at any one time and 2 elevated at each end.

I agree that the driving style is very important and I only have 3 pairs of 4" AndyMark plaction tires, 12 bearings of the 20 I have on hand, and need to order sprockets because I only have 4x 24 tooth sprockets on my 8" used mechanum wheels.

So there's going to be a short blocking delay while I wait for the few little parts I need to do this with just 6 4" wheels total. I am not entirely blocked because I can still start putting things together.

Frame dimensions or wheel spacing?

Re: SD540 Motor Controller
 

I meant 4wd total (2 per side-more turning scrub=more motor work). Honestly the number of wheels isn't that important. Just use whatever you have on hand.

Re: SD540 Motor Controller
 

I will emulate an AndyMark wheel spacing and frame. Thinking about ways to rig the frame so it can drive on 4 or 6.

Aside from that: 8 wheel with 4 down has as much scrub as 4 wheels plus additional chains and losses but I agree it is just a bit more than necessary to test this.

Re: SD540 Motor Controller
 

Consecutive posts because of the time between them:

Orders for the few missing pieces have been placed.
I will start some assembly this weekend.

Re: SD540 Motor Controller (**VIDEO**)
 

In Talon 540's workshop, we shot a short video of our robot running with SD540's, which you can view here: http://youtu.be/9lq6U3EpyTg

There are a total of six SD540 motor controllers on this robot: four for the mecanum wheels, one for the lift, and one for the pneumatic pump.


They worked like a charm! Our team highly suggests you switch to SD540's for the 2016 season competition and onward! The manufacturer, mindsensors, has their main web page at: http://www.mindsensors.com/