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Thread: Motor selection for an all-terrain 6 wheeled robot

  1. #1

    Default Motor selection for an all-terrain 6 wheeled robot

    Hi
    I am building an all-terrain (sand, gravel, slopes, STAIRS) robot with a 6-wheeled design emulating Rocker-Bogie suspension. It has to carry a payload of 10kg throughout the arena of about 500m. I need to buy motors which can take this robot over the terrains mentioned. Clearly stair-climbing is the biggest challenge.
    Please suggest the specifications of motors which can do this task. Presently I think a motor of torque 25kg-cm will do the trick. There is no much constraint in the speed of the vehicle.
    Any suggestions regarding the motors and suitable drivers would be great! Also please suggest some shops from where I can procure very reliable motors along with encoders.

    Regards,

  2. #2
    Administrator T-1000 vikas's Avatar
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    http://www.nex-robotics.com/products...der-motor.html

    They also sell compaitable encoder.

    http://www.nex-robotics.com/products...or-driver.html

    Motor controller ... About 8A capacity.

    Such a project will be expensive , i hope u have a deep pocket.
    Vikas Patial

  3. #3

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    Thanks for the reply. I will look into the links you have given. Hope the motors are very reliable and will not break while operating. Do mention if you have any first-hand feedback about these motors being used in high-torque-requiring systems like the one mentioned.
    Funds are not a worry!

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    Senior Member T-1000 akshay66's Avatar
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    Hi all,
    http://www.vegarobokit.com/product_d...category_id=41

    You can buy these motors too.They are rated 45 rpm at 12v.The torque it around 15Kg.cm........These are quite powerful i am only suggesting you to buy these only if you run them at 24v. In that case you get awesome speed and tourque.i have used them for the same purpose but for a 4xWD.

    http://www.vegarobokit.com/product_d...category_id=46

    Use them for wheels.Good quality & specially for ATR.
    Redefine it your way!!!!

  5. #5

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    Thanks @akshay66.
    The height of the stairs is 17cms. So we need bigger wheels than the one you suggested.
    For stair climbing, what are the essential parameters to be kept in mind?
    Regards,

  6. #6
    Senior Member T-1000 akshay66's Avatar
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    hi all,
    If the total height of the stairs is 17 cms then these are the best.Because the diameter of each wheel is 10 cm naturally the total length of robot will be greater than 30 cms. I'm sure the they will climb the stairs because they have great grip the pattern on the tyre is like of a pulse so they can easily get fixed with stair steps.I'm telling just try them once they will have no problem. My only concern is that what is the angle of stairs.This bot can at the max climb 35 deg.

    One thing more you said something about 10kg load. Distribute the load on the robot evenly and try to put some extraa weight in front so that while climbing stairs and slopes your robot just does not fall back.Put counter weight if required .

    Regards Akshay,
    Redefine it your way!!!!

  7. #7

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    Hey
    The stairs will be perpendicular to the ground like the normal stairs. So I think diameter of the wheel must be around 20cm or more.
    Also the 10kg payload will be in the form of a cube of side 15cm. The motors must be able to carry the total weight of the chassis (20kg to be on the safe side including the payload) over the stairs.
    Will a 20kg-cm motor do the task? Is there a possibility of the bot toppling?
    Regards,

  8. #8
    Senior Member T-1000 akshay66's Avatar
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    hi all,
    I'm getting confused.No point talking like this first clear me about the dimensions of stairs.

    The stairs are made up on several steps which are perpendicular to each other.What is the length of each step and the total length (sum of length of all steps) ??????

    What is the length of bases(base here means the other part than steps, the part on which we keep our feet while climbing) .Now tell me what is the length in your case because it matters a lot.You'll get to know how steep the stairs are.If the length of bases is bigger than length of steps then we can easily do it but if its less then it'll have problems.

    Don't worry about load 6 of such motors can easily carry 20 Kg.The bot will only topple if there is excess of weight on the front side and if you have excess in the bottom side then it might topple while coming down so balance it.I can only tell you some hints main is to be done by you.Try different possibilities.You can learn so much from such competitions if you do it from your heart.


    Regards Akshay,
    Last edited by akshay66; 08-11-2010 at 09:38 PM.
    Redefine it your way!!!!

  9. #9

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    Hi
    There will be 6 steps each of dimension :
    Height: 17cms
    Tread(base): 25cms

    The robot has to climb up as well as down.
    regards,

  10. #10
    Senior Member T-1000 akshay66's Avatar
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    Hi all,
    Thats too much................You'll have to change all the plans.

    These motors wouldn't be able to do job.You won't get wheels with 20cm online you'll have to find them locally or get them fabricated.

    I haven't used these motors but the specifications look attractive:
    http://robokits.co.in/shop/index.php...roducts_id=276

    These motors are fine no need to provide 24v.

    You'll have to think about wheels.Try to get them fabricated.
    You need to buy a compatible motor driver.These motors eat alot of current.

    http://www.nex-robotics.com/products...ntrollers.html


    Regards Akshay,
    Redefine it your way!!!!

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