Questions tagged [transforms]
The transforms tag has no usage guidance.
20
questions
0
votes
1
answer
38
views
What is the meaning of joint space and configuration space and task space?
I'm reading an article about teleoperation systems and it talks about three spaces that include joint space, configuration space and task space frames. I do not know what these are, can you explain?
0
votes
2
answers
101
views
sensor breaks tf tree in ROS
I am currently trying to add sensor(lidar) into my robot. I made base for a sensor, link to which sensor is attached through gazebo reference.
The problem is that adding a tag for some reason creates ...
0
votes
1
answer
69
views
Sending Universal Robots UR5e to specific place Using Camera
I have a UR5e installed with a simple camera on its end effector. The robot is at a known position (Cartesian pose/angles and joint angles)
Using the camera I took a picture of a QR code and got the ...
0
votes
1
answer
169
views
How to republish odometry in different frame?
I have navigation Odometry, but its some how not in the robot body frame. The odometry is being published in world frame, so its not correct. So i need to transform in the robot body frame as that how ...
0
votes
1
answer
345
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
1
answer
1k
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
1
answer
68
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
1
answer
44
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
2
answers
92
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
1
answer
46
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
1
answer
269
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
0
answers
41
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
1
answer
31
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
0
answers
14
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
2
answers
73
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
1
answer
46
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
2
answers
135
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
2
answers
705
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
1
answer
57
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
1
answer
50
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 ...