Human carrying bot

Thread Starter


Joined Aug 19, 2011
I am designing a robot such that it can carry a person from one place to another. I tried about using motors with high torque but found found them too costly!
Can someone recommend me how should I use a low torque motor to drive a person of approx. 60kg weight? :confused:
Also my voltage and current limitations are 23V and 2A respectively.


Joined Jul 17, 2007
If you have such low restrictions on voltage, current, and motor cost, you will have to use some method of creating a mechanical advantage/leverage using reduction gears, pulleys and belts, chain and sprockets, or some other means. The load will be moved more slowly, as you will have to exchange motor speed for increased torque.

The mechanical advantage scheme will also lower the efficiency of the machine, causing more power loss. However, if you only have so much power to deal with, exchanging speed for torque is about the only thing that you can do.


Joined Dec 26, 2010
23V @ 2A comes to only 46W; that may not be enough to get acceptable performance, given that typical powered wheelchair motors are rated in the low hundreds of watts.

You might get something to work at this low wattage with sufficiently low gearing, but it would be slow. Indoors on a flat surface it would be bad enough, but worse for outdoors or climbing slopes.


Joined Oct 15, 2009
Good luck.. Boston Dymanics Big dog robot carries 300+lbs via a 15hp motor (I believe 15hp converts to 11K watts..far from only 46W)

Why don't you start with something smaller (much smaller) given you have such a limited budget.

Thread Starter


Joined Aug 19, 2011
I am thinking of distributing the weights by using ball bearings at the base.
I guess that will require low torque motors. But I am not sure whether this will work or not!:p