Posts by otretas

Thank you all. I found out the problem was in the way i created the Rotation matrix from the unit vectors of the target frames.

By constructing it like this i managed to get the Euler angles like i said:

Rmat =

The poses simulated from the script:

The results obtained with robodk (inputting the angles manually obtained from the script):

Quote from MOM

Checking you screen shot shows that target 2 is actually the flange coordinate system with an angle b of 135 deg (rough guess)

angle b must be in the range of +/90 deg. Doing frame2mat and afterwards an mat2frame will correct this (angle a and angle will change their values and angle b will be in the allowed range.

could this be the problem?

Yes it can be, i am aware of that but ill just make a specific condition for that to give the same orientation or ill implement the code that micahstuh posted from kuka.

I feel like i made the problem a bit confusing but this was just so i can get the orientation of a pose given the vector from the pose coordinates to the target point in space, and the XZ plane of the orientation. The whole idea is that I define a number of poses, the given angle from the base and the distance to the target. This is mainly to use a camera that has manual focus so it needs to face an object with the same orientation in all poses, but i can also use the same concept for other projects like welding,non planar 3d printing, etc..

Hello,

I have been trying to generate orientation positions for the flange in respect to a single point.

I chose to calculate the direction of the vector from the tcp position to this point, in which the orientation of X vector from tcp is inversed from this calculated vector, Y vector parallel to the base, and Z vector pointed to the base. The image below shows the original reference frame from the base (Red - X, Green - Y, Blue - Z), the red dot as the point, and the frames with thin lines, the calculated pose.

To obtain the rotation matrix from the unit vectors i simply fit them in each respective column of the matrix:

Rmat =

From this link from this forum, i know that Kukas rotation order is Rz-Ry-Rx which then to obtain the Euler angles (A,B,C as kuka uses) is then:

C = atan2(Yz, Zz)

B = asin(-Xz)

A = atan2(Xy,Xx)

The A,B,C values obtained from this are not however the expected from the image above. The image below is an example using RoboDk to simulate one pose:

Target 2 X vector should have been following the direction of the position of Target 1 to Target 2.

Am i not able to use the unit vectors in such way to calculate the Euler Angles?