Register to reply

Transposing a line with known references

by _Bd_
Tags: line, references, transposing
Share this thread:
_Bd_
#1
Feb27-13, 12:12 AM
P: 89
Hi, I have a question for a desing I am working on. I want to model it in excel and I am having a hard time finding out how to transpose some lines:


Let Bar B's position and dimensions be known, and I want bar B to be set in 3 positions, I can however apply joints to anyplace near or at bar B, so that I can get a 4-bar-linkage-system that can move as I desire. so for example point A1(x1,y1) and A2(x2,y2) are the joints that are going to hold on to bar B, how do I calculate the new coordinates of A1 and A2 at position 2 if I only know their relationship to bar B at position 1?

I hope this image helps:
http://img526.imageshack.us/img526/4945/thingoz.png



At position 1 i know everything

At position 2 I only know the coordinates of the bottom bar (the red bar) I know where its two end points are, I know its angle (theta) with the horizontal and I know its lenght.
points A1 and A2 have not changed their position with respect to the bottom bar, but they have moved in the plane, how do I calculate their new position?

thank you!

NOTE: THERE IS ROTATION AND TRANSLATION!! (FROM POS 1 to POS 2)
Phys.Org News Partner Science news on Phys.org
Scientists develop 'electronic nose' for rapid detection of C. diff infection
Why plants in the office make us more productive
Tesla Motors dealing as states play factory poker
SteamKing
#2
Feb27-13, 07:50 AM
Emeritus
Sci Advisor
HW Helper
Thanks
PF Gold
P: 6,546
If you know the coordinates at Position 1, and you know the translation and rotation to Position 2, the coordinates of the bar at Position 2 can be calculated by means of a transfer matrix.

The following link shows the procedure:
http://ugweb.cs.ualberta.ca/~c201/F0...ous_coords.pdf
_Bd_
#3
Feb27-13, 12:44 PM
P: 89
The thing about that is that I get weird values when I use that matrix, because they are not rotating around the origin so it creates weird

SteamKing
#4
Feb27-13, 03:57 PM
Emeritus
Sci Advisor
HW Helper
Thanks
PF Gold
P: 6,546
Transposing a line with known references

Then you need to translate the coordinates of Position 1 to the origin of rotation, then apply the rotation matrix.


Register to reply

Related Discussions
Help transposing formula please :-) Introductory Physics Homework 1
Transposing calculation help Introductory Physics Homework 4
Transposing V^2=u^2+2as Introductory Physics Homework 4
Transposing formula General Math 3
Basic Transposing Precalculus Mathematics Homework 1