PDA

View Full Version : which motor for a hexpod



petrick
01-10-2006, 04:02 PM
hi guys
i m building a hexapod.
i know that to control each leg i will need 2 motors. problem is - should i use stepper motors or servo motors and how to control them? please help.
wat should be the size and rating of motors?
if there is a link pls post here.
thanx

taknev13
01-10-2006, 04:23 PM
hey you can actually do it in a few ways using steppers too but it basically boils down to what you size of hexapod is.if you want good torque wid small sizes then servos would be prefffered.n it depends on your budget too..

servos are avalible in india with a few dealers .make a decision then you could contact them.

docel
01-11-2006, 12:37 AM
Hi petrick,
While sero motors can be used for good results, other methods can be used too, with great success.
steppers should not be used: taknev, stop misguiding others

Servo motors cost the earth and the drive ckts cost the moon. Youll need 6 servos max and 3 servos minimum. This is 1400/= x 6 or 3. Here the costly servo is just used as a glorified gear motor.
Consider the hexapod movement: 3 pair of legs moving in pairs in a 'rowing' motion, to and fro. The idea is to lift 1 pair or 1 side of the leg while the other is pushing backwards.
This motion can be made using any gear motor with a cam type drive. It is similar to the 'steam engine ' wheel drive or the 'internal combustion engine' drive :piston up n down turns the wheel....
I f you can convert the motor rotary movement to linear motion, you have the hexapod drive.
See this:
http://www.geocities.com/fuzzyviv/viv/pics.htm

petrick
01-11-2006, 08:17 PM
thanks guys for reply

but i m still not clear.
my robot would be about 18 X 18 inches ang about 8-10 inch high.
it would be weighing around 6-7 kilos.
so i would be needing pretty strong motors wid good precision. kindly give me specs needed and estimate cost. also some shops where i can get them.

if there is some kind of tutorial or a good book on subject kindly sujest.

thanx

vikas
01-11-2006, 11:47 PM
Go to lynxmtion.com ... they have it all ( simply copy there specs ) .

Its better to be safe than end up buying wrong spec servos.

pcube
01-22-2006, 12:21 AM
Hi petrick
since the hexapod has three legs always on floor .you won't need
much stronger servos.only load on a servo is weight of a leg.you can succesfully use stepper motors if the legs are light.
thank you