Need more speed!

jakjrjakjr Posts: 88
edited 2004-08-17 - 21:14:32 in Robotics
I just added the tank tread kit to my BOE-bot and now it seems to have slowed down a bit, I guess its because of the added weight. I even installed new batteries so thats not the problem.


Anyways to my question, somethign along the lines of the 12v stepper motors (form parallax) make my bot go any faster? Im not looking for R/C car type speed, im looking for maybe twice the speed my BOE-bot goes now.


Also, if this type of upgrade will be what im looking for how hard is it going to be to make the switch from servo's to motors (software wise), obviouslly hardware changes will also need to be made but Im not worried about that.


I·just dont want to end up upgrading to motors and have to do 12 hours of programming to switch over from servo's.
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Comments

  • Armored CarsArmored Cars Posts: 172
    edited 2004-08-17 - 09:23:10
    Put in RC ESCs they take the same inputs as servos and you will have lots of power and then some. If you dont want to go that fast you can adjust it in your program easily or experiment with smaller mini motors and ESCs I think Novak makes an ESC for the Mini T that you may be able to just plug in and go.
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2004-08-17 - 12:54:05
    Stepper motors are not the answer -- the require loads of power and unless you're going to add a stepper controller to the mix, will take lots of IO, as well as very detailed programming to maintain a constant speed. You could tray the ESC suggestion (above), or perhaps find different gears for the tank treads (a bigger drive gear should make the tank go faster).

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    Jon Williams
    Applications Engineer, Parallax
    Dallas Office
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2004-08-17 - 13:41:10
    jakjr said...
    I just added the tank tread kit to my BOE-bot and now it seems to have slowed down a bit, I guess its because of the added weight. I even installed new batteries so thats not the problem.
    Having used the tank tread mod extensively, I can tell you this...When you install the tank tread in place of standard wheels for the Boe-Bot, it will automatically be slower at the same servo speed.· This is due to the fact that the standard wheel has a larger effective diameter and thus causes the Boe-Bot to travel farther per servo revolution.

    On the other hand, the Boe-Bot should have more power now.· One other thing to check is are you sending the max speed PULSOUT for each side?· If not you may get a little more speed going with that.· Remember, traditionally tanks move slower than other vehicles.


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    Chris Savage

    Knight Designs
    324 West Main Street
    P.O. Box 97
    Montour Falls, NY 14865
    (607) 535-6777

    Business Page:·· http://www.knightdesigns.com
    Personal Page:··· http://www.lightlink.com/dream/chris
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  • jakjrjakjr Posts: 88
    edited 2004-08-17 - 16:50:12
    Chris Savage said...
    jakjr said...
    I just added the tank tread kit to my BOE-bot and now it seems to have slowed down a bit, I guess its because of the added weight. I even installed new batteries so thats not the problem.
    Having used the tank tread mod extensively, I can tell you this...When you install the tank tread in place of standard wheels for the Boe-Bot, it will automatically be slower at the same servo speed.· This is due to the fact that the standard wheel has a larger effective diameter and thus causes the Boe-Bot to travel farther per servo revolution.

    On the other hand, the Boe-Bot should have more power now.· One other thing to check is are you sending the max speed PULSOUT for each side?· If not you may get a little more speed going with that.· Remember, traditionally tanks move slower than other vehicles.

    Yeah, it has·much more power/traction now, which is good. Yes, I am now using max speed for each servo, before (with the wheels) I had slowed one down to compensate for it not driving straight.


    One more thing, what are ESC's? The only thing Ive heard of with that abreviation·is Electronic speed Controlers, I dont see how they could make it go any faster if the servo's are already going at max speed.
  • Armored CarsArmored Cars Posts: 172
    edited 2004-08-17 - 21:14:32
    ESCs dont control the servos, wich have thier "speed control" built in, they control 550 cans (motors) used to power RC cars, 550 cans or 550 size motors are the RC standard and produce more power than youll ever need. By saying hooking up an ESC we are infering that you also upgrade the motor. Whats nice about them is they hook into the same slots servos do so you dont have to change any programming.
    If the bot is running off servos right now I doubt its big enough to handle 550 power. As I said eirlier, I would check into MiniT ESCs and motors (if you have the money), they are much much smaller, can run off 4AAs or a highperformance pack, and are good RC grade electronics. If you want more info go to Tower Hobbies, hands down best distributer, even lists dementions of most items.

    Good motor and ESC:
    Novak SPY 1870 ~$60
    tri11994 Trinity Minit motor not sure on prices
    TONS of batts available (even matched), I think it uses 7.2v packs
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