# Grasp transformation matrix

1. Feb 19, 2014

### lwcjoseph

Hello everyone, i am now working on a problem with three fingers robot hand to grab a cube to undergo some motion
however i face some difficulties on deriving the grasp transformation matrix which help to switching the local coordinate frame
at first i was given three point vectors [0 1 0]^T, [1 0.5 0]^T, [0 -1 0]^T (T means transpose)
then to calculate a Grasp transformation matrix
i would like to know the step to achieve the result and any general method for deriving the matrix?
thanks very much for your help !

2. Feb 19, 2014

### maajdl

http://commons.bcit.ca/math/examples/robotics/linear_algebra/

http://elvis.rowan.edu/~kay/papers/kinematics.pdf

http://en.wikipedia.org/wiki/Transformation_matrix#Affine_transformations
http://en.wikipedia.org/wiki/Transformation_matrix

I guess you are familiar with matrices to represent linear transformations like rotations.
The only special thing in these "robotic transformation matrices" is the use of a fourth "homogeneous" coordinate.
This allows to represent the group of rotations and translations at the same time, with matrices.

Last edited: Feb 19, 2014
3. Feb 19, 2014

### lwcjoseph

i have read through the materials ,however, the angle of rotation and any other information concerning the transformation has not been given, that's why i have been stucked for so long
the result is as the pic attached
any help?

#### Attached Files:

• ###### Grasp matrix.jpg
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4. Feb 20, 2014

### Inner_Peace

Are these vectors the points on the cube that you need to grasp?
Do you have any information about the base frame and the position/ orientation of the hand?

5. Feb 22, 2014

### lwcjoseph

yes they are the point that i need to grasp, however no other information are povided
that's why i have been stucked so long