Obtaining angular velocity given linear velocity and center of rotation 3D

quarkz · April 5, 2014, 01:21

Hi,

Supposed I'm given linear velocity and center of rotation in 3D. Can I obtain the angular velocity?

I tried using:

v = w x r

v (1x3 vector) = A (3x3 matrix) * w (1x3 vector)

then take the inverse of the 3x3 matrix A and

w = inv A * v

But the inverse of A gave an error.

Why is this so? Are there other ways?

I have the linear velocity and xyz coordinates of its location.

Thanks.

venkateshaero · April 6, 2014, 12:05

please send the data , i will give the solution, u can do in excel itself

quarkz · April 6, 2014, 12:08

Hi venkateshaero,

What I mean is that supposed I know the linear velocity (e.g. = (2,5,-1) and center of rotation (e.g. = (5,3,-2). How can I obtain the angular velocity? How is it done in excel?

Thanks.

cfdivan · April 6, 2014, 15:16

Hi quarkz,

It really looks like you have a 3D rotation which is a little bit more complicated.
Just bear in mind that they behave like vectors if considered infinitesimal rotations. If it is the case, try out to do each one separatly and sum them together at the end.

Regards,

venkateshaero · April 6, 2014, 17:00

I saw ur having problem in matrix conversion

venkateshaero · April 7, 2014, 05:56

we can convert one co-ordinate to other co-ordinate locations, Linear velocity wont be three values

quarkz · April 7, 2014, 06:50

Hi cfdivan, can you explain more how it is done? Thanks.

April 5, 2014, 01:21	Obtaining angular velocity given linear velocity and center of rotation 3D	#1
quarkz Senior Member TWB Join Date: Mar 2009 Posts: 414 Rep Power: 19	Hi, Supposed I'm given linear velocity and center of rotation in 3D. Can I obtain the angular velocity? I tried using: v = w x r v (1x3 vector) = A (3x3 matrix) * w (1x3 vector) then take the inverse of the 3x3 matrix A and w = inv A * v But the inverse of A gave an error. Why is this so? Are there other ways? I have the linear velocity and xyz coordinates of its location. Thanks.

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April 6, 2014, 12:05		#2
venkateshaero Member venki Join Date: May 2011 Posts: 84 Rep Power: 15	please send the data , i will give the solution, u can do in excel itself

April 6, 2014, 12:08		#3
quarkz Senior Member TWB Join Date: Mar 2009 Posts: 414 Rep Power: 19	Hi venkateshaero, What I mean is that supposed I know the linear velocity (e.g. = (2,5,-1) and center of rotation (e.g. = (5,3,-2). How can I obtain the angular velocity? How is it done in excel? Thanks.

April 6, 2014, 15:16		#4
cfdivan Member Join Date: Jun 2011 Posts: 51 Rep Power: 15	Hi quarkz, It really looks like you have a 3D rotation which is a little bit more complicated. Just bear in mind that they behave like vectors if considered infinitesimal rotations. If it is the case, try out to do each one separatly and sum them together at the end. Regards,

April 6, 2014, 17:00		#5
venkateshaero Member venki Join Date: May 2011 Posts: 84 Rep Power: 15	I saw ur having problem in matrix conversion

April 7, 2014, 05:56		#6
venkateshaero Member venki Join Date: May 2011 Posts: 84 Rep Power: 15	we can convert one co-ordinate to other co-ordinate locations, Linear velocity wont be three values

April 7, 2014, 06:50		#7
quarkz Senior Member TWB Join Date: Mar 2009 Posts: 414 Rep Power: 19	Hi cfdivan, can you explain more how it is done? Thanks.