Robot w/ Tranny and LSD

[eaglemike]

Hello there,

I'm currently constructing an uber exploration robot, no remote control what so ever.  I'm currently going for the "all-out" aspect on this thing.  I'm looking at having 1 Drive Motor (Set to 12V), that is connected to an All Metal Automatic Transmission, with the rear-wheels having a LSD.  My issue comes down to this...Brush Motor, Brushless, or what kind of motor do you think I should use for such a thing?  And would 3 gears be enough you think for an all-terrain exploring robot?  Should I maybe do 2 motors working in parallel together on the same gear system to prevent strain at the cost of more battery usage.

As a possible future change-up, or building a newer (or improved) model of this same caliber, do you think I could incorporate it to have an actual Manual Transmission (go with 3 gears at the start) and a clutch?  or do you think the complicity of the thing would result in constant failure and filing for bankruptcy the next day?  I'm sure I would have to incorporate some kind of a sensor to either measure stress in the motor, or speed so it knows when to shift gears.

Your input is much appreciated.  I know my project is massive beyond probably what I can currently handle, but I know this robot will take some serious time, money, and a nagging wife about how much I've invested in this project.

[Soeren]

Hi,

I'm currently constructing an uber exploration robot, no remote control what so ever.  I'm currently going for the "all-out" aspect on this thing.  I'm looking at having 1 Drive Motor (Set to 12V), that is connected to an All Metal Automatic Transmission, with the rear-wheels having a LSD.  My issue comes down to this...Brush Motor, Brushless, or what kind of motor do you think I should use for such a thing?  And would 3 gears be enough you think for an all-terrain exploring robot?  Should I maybe do 2 motors working in parallel together on the same gear system to prevent strain at the cost of more battery usage.

Let me guess... It's the first 'bot you've ever built?

Your input is much appreciated.  I know my project is massive beyond probably what I can currently handle, but I know this robot will take some serious time, money, and a nagging wife about how much I've invested in this project.

Your wife should be allowed at least some nagging rights if you throw yourself at such a project without proper research    (which would have had you going with a single gear, no clutch etc.)

You say you wanna build a robot, but you seem to be more into building a sort of scale model car.
If you had looked a bit into electric cars, you'd have seen that they don't use a (lossy) gears box - just the speeder and brake pedals.

Before you start spreading your hard earned, do read a lot - this (and a wad of flowers) might even shut up your second half 

[eaglemike]

I have built several robots so far.  However, I'm looking at this one to be the grand daddy.  I'm not stopping all my other projects that I've drawn up, it's just that this one is my challenge project.

The project is calling for a modular explorer.  Where input is only needed to inform it of map coordinates needed to be explored outside of standard exploration, or to return to a maintenance station for repairs (assuming errors do not prevent mobility and environmental awareness) or for the exchange of modular devices and mission objectives depending on what is called for.  It will be required to travel uphill at various grades, so I was going for a transmission so it would be able to climb said hill without too much strain on power supply.

I'm using a lot of what I've already produced as the basic design of this robot.  Most of the internal circuitry is already assembled.  All I have left is to construct the chassis, body, and put in all the pieces.

I've done quite a bit of research, and am fully aware of most of the happenings except handling the actual drive part of the thing.  If you think a single speed gearbox is all that is needed, then I can give it a try for the prototype build before doing up the final project.

EDIT: As far as asking which type of motor should I use, I was wondering for honest input in which motors you think would be able to accomplish this task.

[ChrisW]

been a while since i've done anything bigger than modified hobby servos to spin wheels, but if you have a rear dif all ready set up a single drive motor without the transmission is probably your best option. for more speed control options you could check out hobby electronic speed controls (esc) or a funky H-bridge with motor voltage supply controlled via relays. (one of my instructors in school did up that. more power added to the h-bridge with more relays connecting)

as for the type of motor, what size is the project? hobby 1/10 or lawnmower?

if hobby sized project, the brushless outrunners are quite powerful with a good toque. the inrunners are more for high rpm. (Harley cruiser vs the Ninja crotch rocket) either way you will need to have some air flow over the motors & h-bridge or you could loose the project. (flown electric RC aircraft, forgetting to cut holes in the covering for the cooling channel causes a few crashes/fires every year here locally)

if lawnmower sized .... i don't know

don't know if it helps but that's my 0.02
-Chris

[GalacticNerd]

Robot w/ Tranny and LSD

You have no idea how wrong this sounds in my ears.

[madchimp]

Well if it is 1/10 hobby size why not go with prebuilt chassis/drivetrain like the following link
http://traxxas.com/products/models/electric/5607summit

[Soeren]

Robot w/ Tranny and LSD

You have no idea how wrong this sounds in my ears.

Oh, come on, you gotta love Lou 

Holly came from downtown, Nyc
Parked her Batteries via USB
Potted her IR's, ready for play
Shaved her reg-ex and then he was a she

She said
Hey Babe, take a walk on the wild side,
He said Hey honey, take a walk on the wild side.
.
.
.
And the coloured twirls go, doo dodoo...