Motors and gearboxes from the kit

[Kam1310]

Hello everybody,


I just wanted to ask if the gearboxes from the kit can work with one motor instead of two. Will there be any complications? Our team will be really greatful if someone can help us out. Thanks



Sincerely,



Kam

[sanddrag]

It was designed to use either one or two. Check page 11 of this document: http://www.ifirobotics.com/docs/2005...nual-rev-c.pdf Your speed will not really be affected. The only anticipated problems would be a lack of torque. By removing one motor from each gearbox, you are cutting your torque (and overall power) in half. This may depend on what your wheel arrangement and tread is but you may lose available pushing force. Also, it is possible your robot may have trouble turning. Last, you may experience circuit breakers tripping due to increased individual current draw on the motors (because they are no longer sharing the load with another motor). If you encounter these problems, you can put a smaller sprocket on the gearbox shaft and/or a bigger sprocket on the wheel. And/or use smaller wheels. Or just keep all the motors.

Do you know what speed (in feet per second) your robot is currently geared for?

[EricH]

Team 330 used the kit gearboxes with one motor to prototype a drive, then converted them back to two motors per box for competition. If one motor doesn't work for you, then expect to take about an hour to 1) pull gearboxes from mountings, 2) disassemble gearboxes partway, 3) add second motor, and 4) reinstall gearboxes.
And to answer the second question, unless you really screw up there should be no major complications, other than the ones your drive may already have.

[Kam1310]

First i will like to thank u,

Second, we are using two motors at the moment but our robot is currently overwieght by a bit, so we considered using 1 motor to reduce wieght. I will try finding out how fast our robot is because im not too sure of it myself and i will find out the size if our wheels since our wheels are wider and bigger then the ones in the kit.

[Tom Bishop]

Wow, losing motors to loose weight! I would look other places to loose your weight if possible. You will likely need the torque from the 2 motors in this years game. The motors will save you at least a pound each but that's what drills and hole saws are made for!!!

[EricH]

Originally Posted by Tom Bishop

Wow, losing motors to loose weight! I would look other places to loose your weight if possible. You will likely need the torque from the 2 motors in this years game. The motors will save you at least a pound each but that's what drills and hole saws are made for!!!

And what happens if some one has already removed all the weight they can through holes? They have to remove motors. And the CIMs are closer to two pounds apiece...

[jrocket567]

Originally Posted by EricH

Team 330 used the kit gearboxes with one motor to prototype a drive, then converted them back to two motors per box for competition. If one motor doesn't work for you, then expect to take about an hour to 1) pull gearboxes from mountings, 2) disassemble gearboxes partway, 3) add second motor, and 4) reinstall gearboxes.
And to answer the second question, unless you really screw up there should be no major complications, other than the ones your drive may already have.

an hour?!?!?! we pulled ours completely apart and back together in the time we had between two matches... had to do so because of a strong right hand lean-- turned out to have a drill bit in one of the gearboxes, which placed a nice little groove in one of the spur gears...if you decide to start pulling boxes apart, just make sure you do not loose any parts and you know how well they go together
on the one motor system, we ran ours for a match that way, and it worked fine.. but look for weight elsewhere before sacrificing motors

[Kam1310]

We havent drilled holes Yet, but we will be soon because our competion does not start until march 31. At the moment we are really desperate to loose wieght because our robot is about 8-10 pounds over wieght. We are plan is to skip some practise rounds if we have to, to work on our bot so taking and putting back the motor shouldn't be a problem.

[Biff]

Originally Posted by Tom Bishop

Wow, losing motors to loose weight! I would look other places to loose your weight if possible. You will likely need the torque from the 2 motors in this years game. The motors will save you at least a pound each but that's what drills and hole saws are made for!!!

Cims are 2.8125 lbs each, and victors are 3.8oz painfull to lose them but it may be our best choice. Just hope our scale was off about 6 lbs.

[sanddrag]

Originally Posted by Kam1310

We havent drilled holes Yet, but we will be soon because our competion does not start until march 31. At the moment we are really desperate to loose wieght because our robot is about 8-10 pounds over wieght. We are plan is to skip some practise rounds if we have to, to work on our bot so taking and putting back the motor shouldn't be a problem.

Umm, are you saying you plan on drilling holes in something between now and March 31st? That would be against the rules. Anyway, are you using pneumatics? If so, maybe you can store enough air to remove the compressor, try turning the pressure down on the regulator. Or, do you have two tanks? Maybe you can remove one.

When you consider that the density of 6061 aluminum is only .098 lbs per cubic inch, holes really don't save much. If you can put holes in your sprockets, then you will save weight. Also, take a look at what aluminum plates you have on your robot, and as yourself if they realy need to be that thick. 1/4" plate is almost never needed, 3/16" will do. This year, we aren't using anything thicker than 1/8" plate. Also, a thin piece (1/16") of 1x1 or smaller L angle bolted or riveted to a thin plate is just as good if not better than a whole thick plate by itself. If you can take mass out of a whole sheet by going thinner, you will be better off than drilling lots of holes in a thick plate. Take some thinner materials with you to the competition. You should consider plastics as well.

[ttedrow]

Team 1310,

Here is one suggestion. As soon as you uncrate your bot, take it to the weigh station. The inspector will not be busy and they will be able to help with putting your bot on a diet.

2005 Palmetto Lead Inspector

[Al Skierkiewicz]

Originally Posted by ttedrow

Team 1310,

Here is one suggestion. As soon as you uncrate your bot, take it to the weigh station. The inspector will not be busy and they will be able to help with putting your bot on a diet.

2005 Palmetto Lead Inspector

Agreed! Inspectors are your friends! And don't wait, come early and get a good seat.
Boilermaker and Midwest Lead inspector

[NoodleKnight]

When team 100 used the gearboxes with only one motor they made a noticable grinding sound, at first we thought we assembled them wrong, but there was no visible damage and once we added the second set of motors, it sounded much better.

Before cheeseholing and throwing out motors, see if you can scrap metal plates (replace them with lexan if necessary), or just cutting pieces of heavy material out, getting rid of nuts/bolts where they aren't exactaly crucial. Maybe clean out those metal shavings caught in the corners of your frame! Every little bit counts.

[elknise]

Well, at our practice competition, we found out our robot was 14 pounds heavy, so we drilled a lot of holes in the sprockets and our 6061 Aluminum box and our 2"x6" box beam that is the base of our arm. We think we lost about 12 or 13 pounds based on weighing the shavings and pieces we cut out and decided to save. We hope the scale was a little off. We considered removing a motor, but we remembered that we did the calculations with one and two and one would just not work at all. Also, we plan if we are more than a pound off to take out the compressor and add a tank which will save us about 2 pounds.

[Tom Bishop]

Sprockets are a great place to loose weight. We put eight 1" holes in each of our 4 48 tooth drive sprockets and lost about a pound each. Sprockets are hardened steel, and will be difficult to drill without a press or a mill. It might be that a team has a mobile shop at the regional that you could use. We also lost about a pound by drilling out the side holes of the kitbot frame to 7/16". You can do that with a hand drill and some good arm strength! Watch out though, the hand drill will tend to "grab" and torque the drill around, possibly smashing fingers against the table top. We used a 6" hole saw to drill out the top plate where we put the Robot controller. Any solid pieces of metal are good candidates for holing.

What regional are you attending? Maybe a team with a mobile shop can let you know if they will be at your regional and can help with what is likely to be a lot of work and reassembly, as well as other teams that could help. Good luck and I hope things turn out well for you.