Does this seem right to you?

Lynxmotion Legged Robots
1

I’ve been calculating the torque needed for a knee joint in a 10kg hexapod, with lower leg length 1m, upper leg length 0.7m and width of body 0.6m. The motors would be 300g each.

It’s a pretty hefty robot. Anyway, I arrived at the answer of 415.2Nm of torque needed for the knee, static, three legs on the ground, value for the side with only one leg down, so a motor of maybe 600Nm needed.

I’m not asking for precise calculations, but does that figure feel right to you guys? It seems pretty high, but then, as I said, the 'bot isn’t exactly going to enter a featherweight contest any time soon.

:wink:

Thanks,

theChipmunk

2

Try this out…

box.net/shared/2d49sae2pm

It’s a torque calculator that I modified from the society of robots arm torque calculator. Good luck.

3

P.S. I get 35.3 Nm or 5000 oz-in

4

Now, you see, that sounds a) much more like it and b) a helluva lot more manageable!

Thanks for the link!

:smiley:

theChipmunk

5

Best to multiply by factor of 1.5 to 2 to account for the dynamic changes of the robot, especially when you need to do body movement.

By the way, 35.3 Nm is a lot of torque! :exclamation: