CIM Motor Sacrifice

[PayneTrain]

We might try the cimulator for launch, and then change over to an FP set once BaneBots breaks my heart all over again.

I gave my bot to you, BaneBots, and then you just short it all away? *tears*

[JamesCH95]

Assuming the shooter in a given robot is higher than the drive train motors (likely) I think that using the 775s to shoot is a good choice because they weigh about 2lbs less than a CIM. Keeping weight low in the robot will be very important for balancing and going over the barrier.

We're planning on having our shooter at the top of the robot, so keeping 4lbs at the bottom will help make the robot more stable while only sacrificing a little bit of shooting power.

[Grim Tuesday]

Wait, when was it decided that 775's are better than FP's?

[Hawiian Cadder]

Our plan is to put 4 CIMs in the drive-train. With single motor drive and trying to balance, especially attempting to push other robots on the ramp (single person controlling the balance instead of 2 or even 3. This is accomplished by a low level of stall by the other balancing robot against your robot, and then back-driving or sliding the other robot to control the balance.) would be all but impossible without either 2 speed gearboxes or a 4 CIM drive. I would recommend the CIM SIM from andymark as an alternative power method for flywheels, belts, conveyors, and other high power systems. A pair of 500 series motors will actually perform better than a single CIM in most cases, and with the gearbox is comparable on weight. I try to avoid the RS-775, because they don't offer the same benefit/weight as the other motors, designed properly, the fragility of some of the 500 series motors wont be a problem, and there are more gearbox options which allows for the possibility of keeping it lighter with more power.

[Daniel_LaFleur]

Originally Posted by Peter Matteson

We have faaaaaaaaaaaaaar more motor power than we ever had available in the past this year. If you you can't figure out how to use the 22 available motor to make all you mechanisms and drive work then I would love to know what you're planning. We may not have the mini-bike motors we had during 2006 but we have far more power available with the replacements.

I'll be honest. I'm more worried about battery power droop than our motors. I believe you will see a lot of robots resetting 1.2 way through the match because they are running so many motors.

Just my 2 cents

[Peter Matteson]

Originally Posted by Daniel_LaFleur

I'll be honest. I'm more worried about battery power droop than our motors. I believe you will see a lot of robots resetting 1.2 way through the match because they are running so many motors.

Just my 2 cents

Completely agree with you. I've been waiting for them to do this for a few years because it makes sense to give more than we can use and force tradeoffs.

[Jon Stratis]

For your consideration... our prototype shooter managed to score fairly consistently from the key last night running off two cordless drills (which are closer to 550's than CIM's). With the plethora of motors this year, you could easily stick 4 BB motors on the shooter (and have enough motors for everything else you want to do), and get 1000W of power out of them for shooting. That's more power than two CIM's!

[Walter Deitzler]

Originally Posted by eagle33199

For your consideration... our prototype shooter managed to score fairly consistently from the key last night running off two cordless drills (which are closer to 550's than CIM's). With the plethora of motors this year, you could easily stick 4 BB motors on the shooter (and have enough motors for everything else you want to do), and get 1000W of power out of them for shooting. That's more power than two CIM's!

How far did it shoot? If two CIMS can accuratly shoot a ball farther than 4 BB's, there is an advantage right there.

[Jon Stratis]

With the two drills, it was making it from the key into the top basket with about a 45 degree angle. As far as baskets go, that's probably about the furthest I'd realistically plan for on the field (which won't stop us from trying for further, of course!), if only due to the protection available there.

Note that we didn't use actual KoP motors, we didn't spend any time figuring out proper gear ratios or speed... this was just a prototype. I would imagine that 4 similar BB motors, properly geared, would be able to clear half court pretty easily based on what we saw last night, if that's what you're going for. Once you get it past half court, is there much of a benefit to shooting further?

[greasemonkey]

this can be avoided by gearing smaller motors thats what were doing for right now at least

[Ether]

Originally Posted by greasemonkey

this can be avoided by gearing smaller motors thats what were doing for right now at least

What does the pronoun "this" refer to ?

[Aren Siekmeier]

I think this thread needs some numbers to justify the motor comparisons going on. As stated above, power is what matters, because you can gear all the motors to the same speed, and if they have the same power, the torque will be more or less the same (ignoring some inefficiencies).

The CIM has a max power of about 337W.
The FP-2011 has a max power of about 289W.
The RS775-18V (powered at 12V) has a max power of about 266W.

So they are somewhat close, with CIM beating FP beating RS775. Since the CIM is so much larger, most people will agree that it's the motor to put in the drivetrain since it will take continuous duty all day (relatively speaking). The FPs and RS775s will be more sensitive to overheating and would be better suited to intermittent duty, i.e. a shooter (even if the wheels are always spinning, they are only loaded down when you shoot, which will be relatively infrequent).

We also have a much larger limit on quantity in past years. Even with 4 CIMs in the drivetrain, you can have another 2 FPs and 4 RS775s, besides all the other motors at our disposal. So you can make up for another 4 or 5 CIMs in power, but of course your battery will start complaining before long.

We are foreseeing something like 4 CIM drive, 2 FP shooter, and various smaller motors for collection and loading, based on our testing so far.

[3747Mentor]

I have heard no mention about the wide array of automotive motors available to teams this year. If power is a concern, there are some very powerful Denso motors used in seats that would be legal for use.

[JamesCH95]

Originally Posted by 3747Mentor

I have heard no mention about the wide array of automotive motors available to teams this year. If power is a concern, there are some very powerful Denso motors used in seats that would be legal for use.

Do you have power specs for them? Historically the seat motors have not been very powerful (they have been KOP in past years).

[Jon Stratis]

Originally Posted by 3747Mentor

I have heard no mention about the wide array of automotive motors available to teams this year. If power is a concern, there are some very powerful Denso motors used in seats that would be legal for use.

How are you defining power? Check out the official specs for this year's motors:
http://www.usfirst.org/sites/default...torInfo2.2.pdf

The normal Denso motors we've gotten the past few years can provide a lot of torque (which is NOT equivalent to power!), true... but they're so slow, the overall power output is really low. Likewise, the third one listed on the sheet might be faster, but doesn't provide near as much speed or torque as other motors listed (like the FP or the 775's).