How to Derive the Grasp Transformation Matrix for a Three-Finger Robot Hand?

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Discussion Overview

The discussion focuses on deriving the grasp transformation matrix for a three-finger robot hand intended to grasp a cube. Participants explore the mathematical and conceptual aspects of transforming local coordinate frames in robotic applications.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant describes the challenge of deriving the grasp transformation matrix given specific point vectors representing the points on the cube to be grasped.
  • Another participant suggests reviewing introductory materials on linear algebra and transformation matrices, noting the significance of homogeneous coordinates in robotic transformations.
  • A participant expresses frustration due to a lack of information regarding the angle of rotation and other transformation details, which are necessary for completing the calculation.
  • Further clarification is sought regarding whether the provided vectors represent points on the cube and if any information about the base frame or the hand's position and orientation is available.
  • A participant confirms that the vectors are indeed the points to grasp but reiterates the absence of additional information, contributing to their difficulties.

Areas of Agreement / Disagreement

Participants generally agree on the need for additional information to derive the grasp transformation matrix, but no consensus exists on how to proceed without that information.

Contextual Notes

The discussion highlights limitations related to missing assumptions about the robot hand's orientation and the specific transformation details required for the grasping task.

lwcjoseph
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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 !
 
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Read some of these introductions:

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_matrixI 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:
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?
 

Attachments

  • Grasp matrix.jpg
    Grasp matrix.jpg
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lwcjoseph said:
at first i was given three point vectors [0 1 0]^T, [1 0.5 0]^T, [0 -1 0]^T (T means transpose)

Could you please answer these so that I can understand your question better?
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?
 
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
 

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