Questions tagged [transforms]
The transforms tag has no usage guidance.
16
questions
0
votes
1answer
36 views
TF is broken when using robot_localization package with only IMU sensor, how to assure that the measured velocity is the one from the robot?
Im using thisrobot_lokalization robot_localization package for the linear velocity. As only sensor input in my case is IMU. I configure the parameters and set the frames as follow
...
0
votes
1answer
39 views
Static transform difference between command line and launch file
I'm having a problem setting up the static transform between my base_link and my camera.
If I use rosrun tf static_transform_publisher in a different command line the camera is alligned with my axes ...
0
votes
1answer
37 views
Identifying joints from transformation matrix (DH matrix)
Given a transformation matrix formed using the Denavit Hartenberg method, is there a way to identify joint paramters: for example the order of joints?
I've come across a solution to an exam question ...
0
votes
1answer
15 views
doubt regarding the base_local_planner::transformGlobalPlan() function
I am trying to understand the base_local_planner::transformGlobalPlan() function.
As per my understanding, the function takes in the global_plan (generated by the <...
0
votes
2answers
34 views
Significance of fixed_frame parameter in lookupTransform function
I was going through the implementation of the lookupTransform function defined inside the base_local_planner::getGoalPose() function.
What is the significance of ...
0
votes
1answer
32 views
Transform Velocity data from sensor frame to world frame
I am new to Robotics and transformation topics. I need help in understanding and solving the below problem.
I have data (surrounding obstacle position, orientation and velocity) which are in sensor ...
0
votes
1answer
94 views
How to make two frames relative to each other
I have a Velodyne and camera that both have transformations specified relative to the origin of the robot.
The original transformations were specified as yaw, roll, pitch, x, y, z. I wrote a script to ...
0
votes
0answers
31 views
Finding orientation of object in 3D space
Given the above constellation, I have to find the orientation of object B in the coordinate system of Object C. The objects A and B are fixed to a certain place and the object C can move in freely in ...
0
votes
1answer
16 views
Determining Base Configuration Tsb from End-Effector Configuration Tse for youbot
Hello there, hope you are doing great.
Right now I am trying to control youbot to pick and cube and place it to a certain position, on simulation. However, I believe that the reference trajectory is ...
1
vote
0answers
13 views
Getting the new heading after a Transformation
Lets say I have 2d poses as such (angles in degrees):
world_to_robot = {0, 4, 45} robot_to_object = {4, -4, -45}
From a graph it would be easy to see that:
world_to_object = {4, 8, theta}, what goes ...
2
votes
2answers
60 views
Compute path in absolute frame from sequence of measurements
I have a sequence of measurements $\{(x_i, y_i, \theta_i)\}_{i = 1 \:...\: N}$. Each of these represents the new pose of the robot seen from the previous pose, i.e. a measurement $(x', y', \theta')$ ...
0
votes
1answer
40 views
Motion model and homogeneous transformation issue on a drone
I am trying to develop a EKF-SLAM algorithm for a drone, and I want to estimate its position in the inertial/world reference frame. I have as control variables the linear and angular velocities in the ...
1
vote
2answers
95 views
Understanding Twists as 3D Velocities
I am just learning about twists to represent 3D velocities (e.g. of a robot's end-effector), and I have two questions:
1) Wikipedia defines a twist as "an angular velocity around an axis and a linear ...
0
votes
2answers
362 views
How to calculate rotation angle from 3D points
I have 4 3d points(x, y, z). Using these points how can I calculate rotation angle? Consequently, I want to have a 4x4 transformation matrix including rotation and translation information.
4 points ...
0
votes
1answer
50 views
Reference frame, vector
How do I specify the directions of a unit vector $X_n$ and $Y_n$ of a frame $\{n\}$ at an angle $θ$ relative to a frame $\{a\}$ in the form
$$
X_n=cosθX_a + sinθY_a
$$
$$
Y_n=-sinθX_a+cosθY_a
$$
? Can ...
1
vote
1answer
49 views
Absolute 2D pose from previous pose and measurement
I have a pose $\boldsymbol{x}_0 = (x, y, \theta)$ in an absolute frame, right-handed and centered in (0, 0, 0). I obtain a measurement $\boldsymbol{m} = (\Delta x, \Delta y, \Delta \theta)$ in the ...