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Topic: Servo motors for spider (Read 743 times) previous topic - next topic

rigel012

I need to know if there are a cheaper model of servo motor used to create this spider.

http://www.youtube.com/watch?v=2IAZpuwhqew

The model of motor in this video is a HITEC HS-645MG but I found they costs about 30-35$ each. I need 24 of them to create the spider so the total cost exceed my budget. The specifics tell the 645MG is built for about 10kg/cm. I think I can use half of that power to build my spider and so save much money. The body of the spider is built in plywood, not with metal so the weight shouldn't be eccessive.

Do you know a model that can allow me to build a version of it without spend a thousand dollars?

DuaneB

Hi,
   Check the same page you found the price of the Hitec servo, cheap servos start at less than 10 dollars and can be found for a lot less if you are buying in bulk which I assume you will be.

   Looking at the spider, most of the servos are acting against quite a lot of leverage, you should consider this as you might need reasonable power to deal with the leverage.

Duane B

rcarduino.blogspot.com
Read this
http://rcarduino.blogspot.com/2012/04/servo-problems-with-arduino-part-1.html
then watch this
http://rcarduino.blogspot.com/2012/04/servo-problems-part-2-demonstration.html

Rcarduino.blogspot.com

rigel012


   Looking at the spider, most of the servos are acting against quite a lot of leverage, you should consider this as you might need reasonable power to deal with the leverage.
Do you think that 5 kg/cm are enought to keep up the body against gravity in a standard static position like when the spider is at the start in the video? I honestly need someone that can tell me: "buy it that is right for you" :)

zoomkat

Quote
I honestly need someone that can tell me: "buy it that is right for you"


Then you buy servos that are known to work in multi legged bots. Do a google search for "servo hexapod" to see what a lot of other people have used. Below is a small hexapod that uses small inexpensive servos, which would make for an inexpensive first project.

http://letsmakerobots.com/node/19257
Consider the daffodil. And while you're doing that, I'll be over here, looking through your stuff.   8)

Chagrin

The servos he's using are dual ball bearing and have three metal gears. That adds a lot of durability but not power.

When you're selecting your servos you should certainly pick ones that have a metal output gear at the minimum.

rigel012

Then could I choose a servo with metal gears but with a less torque than 10 kg/cm as he used?

MarkT

Build it smaller and lighter, then smaller less powerful servos should do (and are presumably cheaper)?  You might want to build a single limb first and measure its performance with cheap servos and see if a full octopod robot is feasible...
[ I won't respond to messages, use the forum please ]

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