Links¶
This node provides a way for the user to introduce new coordinate systems by inserting transformations between two coordinate systems. This allows to adjust camera positions in a flexible way, e.g. when a camera is mounted on a robot hand and moving with it.
Example
After mounting the camera on the robot and performing a hand-eye calibration with the corresponding command, the camera “120001” is by default linked to the coordinate system “Hand” by its Target node. 3D data computed by the camera is now in the coordinate system “Hand” and as the camera moves with the robot, the coordinate system also moves. In order to get the 3D data in a static coordinate system, a new link from Hand to the world coordinate system (e.g. “RobotOrigin”) can be introduced as a subnode here. The extended LinkTree then looks like this:
![digraph link_tree_example {
graph [
rankdir = LR
]
Camera [
label="120001"
style="solid, filled"
fillcolor="lightblue"]
Hand [
label="Hand"
style="solid, filled"
fillcolor="orange"
]
RobotOrigin [
label="RobotOrigin"
style="solid, filled"
fillcolor="orange"
]
Camera -> Hand -> RobotOrigin
}](_images/graphviz-f475265b40279ffe8ad1350c9075b672e6a872aa.png)
The link “120001” → “Hand” is contained in the camera’s Link node and the link “Hand” → “RobotOrigin” is specified as the subnode Hand of this node. By updating the transformation between “Hand” and “RobotOrigin” as the robot is moving, the computed 3d data of the camera will be in the static coordinate system “RobotOrigin”.
Format
Object/Transformation |
Each subnode describes a Transformation between the coordinate system specified by the name of the subnode and the specified target coordinate system. With the above example, which can be seen here, the transformation description is: Reference: Hand. Target: Workspace. |