4 votes

Is the translational vector (positon) in transformation matrices in cm or another unit (MATLAB)?

They are in whatever units the kinematic analysis uses. It could be feet, inches, meters, millimeters, or whatever. Your question is a bit like asking “what unit is the Pythagorean theorem written ...
  • 4,346
3 votes

World and Map Frame for a real robot

As you've figured, static transforms are valid for fixed offsets such as sensor positions. They are the minimal solution the more complete recommended solution is to setup a robot model. There's ...
  • 1,364
2 votes
Accepted

Calculate transform from different poses

I am just going to explain from the basics. So feel free to skip through the first part and scroll to the bottom if you want the answer. Basics: The 3 parameters of your pose are $x,y,\theta$. These ...
  • 1,581
2 votes

Obtaining Heading vector from IMU

Probably the easiest way to do this would be to convert from Quaternion to Roll-Pitch-Yaw rotations, and then your heading is the Yaw angle. I'll note that the Yaw angle is not fixed/correct unless ...
  • 15.1k
2 votes
Accepted

Conveyor Belt Calibration for a Robot - Rotation Matrix

A general approach would be to construct a so called axis-angle representation and convert that to a rotation matrix representation. On order to do so, one could start with a normal vector of the ...
  • 6,497
2 votes
Accepted

orientation transformation

Your 6d vector can also be considered a frame. Lets call it the frame of the object. Convert your 6d vector to something easier to work with like Homogeneous Transforms. Another alternative is ...
  • 1,581
1 vote

homogeneous transformation matrix only given sensor extrinsic values

You can do this easily just by using homogeneous transformation. Attach a local frame to each sensor , and make sure your sensor measurements can be represented in this frame. For example, I would ...
  • 111
1 vote

How to get transform between two fixed frames using a camera

The most simple and easy way is using a common third frame. Attach a camera to the end effector of each robot and place a calibration board on the ground. Do a hand to eye calibration using the ...
  • 1,385
1 vote
Accepted

URDF for a real robot

For a real robot, do I need a URDF as well? It is not necessary to create a URDF for a real robot, but it's highly recommended. Many of the tools are designed to leverage it. For example the ...
  • 1,364
1 vote

Relative rotation and a new reference frame as the rotation of the first object

I've found the solution. Instead of using intrinsic matrix to angle conversions such as: $yaw = atan2(R_{n_{1}\leftarrow n_{2}}(2,1),R_{n_{1}\leftarrow n_{2}}(1,1))$ $pitch = asin(−R_{n_{1}\leftarrow ...
  • 21
1 vote

How to do transformation to get correct linear velocity from linear acceleration IMU data?

What you have stumbled upon here is a classic problem in robotics; where am I? Localization is a hard to solve problem. Every sensor will have associated noise and accurately figuring out velocity and ...
1 vote
Accepted

velocities transformations between frames

Yes it is. The rotation matrix of the coordinates system B relative to the coordinate system A or its inverse backwards, A relative to B.
  • 6,497
1 vote
Accepted

calculation sequences when using RPY-transformation vs Euler-transformation

I would like to add to your answer a simple concept i used to understand rotation matrices. So, first you rotate the x- axis. No problem here.R=[x] Second, you rotate the already rotated axes(that was ...
1 vote

Elegant way to mathematically relate joint positions (without a root/base joint) for easy re-rooting?

If $T^{ee}_{root}$ is the homogeneous transformation that relates coordinates expressed in the end-effector frame into coordinates expressed in the root frame, then it holds that $T^{root}_{ee} = \...
1 vote

Transform Velocity data from sensor frame to world frame

You can use the rotation matrix. linear_v= R*sensor_linear_v + p X sensor_angular_v p is the translation vector and the X is the cross operator angular_v=R*sensor_angular_v

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