# Com for robot

1. Aug 21, 2011

### iro2010009

hii..

this is shruti...
i want to make an inverted linear pendulum of bi ped humanoid robo...
can any 1 help me in calculating the centre of mass and centre of gravity... of a humanoid robot......

2. Aug 23, 2011

### tiny-tim

welcome to pf!

hi shruti! welcome to pf!

centre of mass and centre of gravity of a robot on Earth are the same thing

to find the centre of mass of the whole robot at time t, find the centre of mass of each part (leg etc) at time t, then use the usual formula to find the overall centre of mass

3. Aug 24, 2011

### tiny-tim

hi shruti!

if you have a robot like Fujitsu's http://home.comcast.net/~jtechsc/HOAP-3_Spec_Sheet.pdf" [Broken],

find the mass of each individual part (leg, head, etc), and find the position of the centre of mass of each part (the parts are reasonably regular, should that should be fairly easy)

then if the masses are m1 m2 etc, so that the total mass is M = m1 + m2 + …

and if the centre of mass of the nth part is at position (xn, yn, zn),

then the centre of mass is at ([x1 + x2 + …]/M, [y1 + y2 + …]/M, [z1 + z2 + …]/M)

Last edited by a moderator: May 5, 2017