Next, in a new terminal, run the stretch ArUco launch file which will bring up the [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_core/stretch_core/detect_aruco_markers.py) node.
Next, in a new terminal, run the stretch ArUco launch file which will bring up the [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_core/stretch_core/detect_aruco_markers.py) node.
```{.bash .shell-prompt}
ros2 launch stretch_core stretch_aruco.launch.py
```
Within this tutorial package, there is an [RViz config file](https://github.com/hello-robot/stretch_tutorials/blob/iron/rviz/aruco_detector_example.rviz) with the topics for the transform frames in the Display tree. You can visualize these topics and the robot model by running the command below in a new terminal.
Within this tutorial package, there is an [RViz config file](https://github.com/hello-robot/stretch_tutorials/blob/humble/rviz/aruco_detector_example.rviz) with the topics for the transform frames in the Display tree. You can visualize these topics and the robot model by running the command below in a new terminal.
```{.bash .shell-prompt}
ros2 run rviz2 rviz2 -d /home/hello-robot/ament_ws/src/stretch_tutorials/rviz/aruco_detector_example.rviz
@ -37,9 +37,9 @@ ros2 run stretch_core keyboard_teleop
</p>
### The ArUco Marker Dictionary
When defining the ArUco markers on Stretch, hello robot utilizes a YAML file, [stretch_marker_dict.yaml](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_core/config/stretch_marker_dict.yaml), that holds the information about the markers.
When defining the ArUco markers on Stretch, hello robot utilizes a YAML file, [stretch_marker_dict.yaml](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_core/config/stretch_marker_dict.yaml), that holds the information about the markers.
If [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_core/stretch_core/detect_aruco_markers.py) node doesn’t find an entry in [stretch_marker_dict.yaml](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_core/config/stretch_marker_dict.yaml) for a particular ArUco marker ID number, it uses the default entry. For example, most robots have shipped with the following default entry:
If [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_core/stretch_core/detect_aruco_markers.py) node doesn’t find an entry in [stretch_marker_dict.yaml](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_core/config/stretch_marker_dict.yaml) for a particular ArUco marker ID number, it uses the default entry. For example, most robots have shipped with the following default entry:
```yaml
'default':
@ -72,7 +72,7 @@ and the following entry for the ArUco marker on the top of the wrist
'length_mm': 23.5
```
The `length_mm` value used by [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_core/stretch_core/detect_aruco_markers.py) is important for estimating the pose of an ArUco marker.
The `length_mm` value used by [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_core/stretch_core/detect_aruco_markers.py) is important for estimating the pose of an ArUco marker.
!!! note
If the actual width and height of the marker do not match this value, then pose estimation will be poor. Thus, carefully measure custom Aruco markers.
@ -81,26 +81,26 @@ The `length_mm` value used by [detect_aruco_markers](https://github.com/hello-ro
'use_rgb_only': False
```
If `use_rgb_only` is `True`, [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_core/stretch_core/detect_aruco_markers.py) will ignore depth images from the [Intel RealSense D435i depth camera](https://www.intelrealsense.com/depth-camera-d435i/) when estimating the pose of the marker and will instead only use RGB images from the D435i.
If `use_rgb_only` is `True`, [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_core/stretch_core/detect_aruco_markers.py) will ignore depth images from the [Intel RealSense D435i depth camera](https://www.intelrealsense.com/depth-camera-d435i/) when estimating the pose of the marker and will instead only use RGB images from the D435i.
```yaml
'name': 'wrist_top'
```
`name` is used for the text string of the ArUco marker’s [ROS Marker](http://docs.ros.org/en/melodic/api/visualization_msgs/html/msg/Marker.html) in the [ROS MarkerArray](http://docs.ros.org/en/melodic/api/visualization_msgs/html/msg/MarkerArray.html) Message published by the [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_core/stretch_core/detect_aruco_markers.py) ROS node.
`name` is used for the text string of the ArUco marker’s [ROS Marker](http://docs.ros.org/en/melodic/api/visualization_msgs/html/msg/Marker.html) in the [ROS MarkerArray](http://docs.ros.org/en/melodic/api/visualization_msgs/html/msg/MarkerArray.html) Message published by the [detect_aruco_markers](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_core/stretch_core/detect_aruco_markers.py) ROS node.
```yaml
'link': 'link_aruco_top_wrist'
```
`link` is currently used by [stretch_calibration](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_calibration/stretch_calibration/collect_head_calibration_data.py). It is the name of the link associated with a body-mounted ArUco marker in the [robot’s URDF](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_description/urdf/stretch_aruco.xacro).
`link` is currently used by [stretch_calibration](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_calibration/stretch_calibration/collect_head_calibration_data.py). It is the name of the link associated with a body-mounted ArUco marker in the [robot’s URDF](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_description/urdf/stretch_aruco.xacro).
It’s good practice to add an entry to [stretch_marker_dict.yaml](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_core/config/stretch_marker_dict.yaml) for each ArUco marker you use.
It’s good practice to add an entry to [stretch_marker_dict.yaml](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_core/config/stretch_marker_dict.yaml) for each ArUco marker you use.
### Create a New ArUco Marker
At Hello Robot, we’ve used the following guide when generating new ArUco markers.
We generate ArUco markers using a 6x6-bit grid (36 bits) with 250 unique codes. This corresponds with[ DICT_6X6_250 defined in OpenCV](https://docs.opencv.org/3.4/d9/d6a/group__aruco.html). We generate markers using this [online ArUco marker generator](https://chev.me/arucogen/) by setting the Dictionary entry to 6x6 and then setting the Marker ID and Marker size, mm as appropriate for the specific application. We strongly recommend measuring the actual marker by hand before adding an entry for it to [stretch_marker_dict.yaml](https://github.com/hello-robot/stretch_ros2/blob/iron/stretch_core/config/stretch_marker_dict.yaml).
We generate ArUco markers using a 6x6-bit grid (36 bits) with 250 unique codes. This corresponds with[ DICT_6X6_250 defined in OpenCV](https://docs.opencv.org/3.4/d9/d6a/group__aruco.html). We generate markers using this [online ArUco marker generator](https://chev.me/arucogen/) by setting the Dictionary entry to 6x6 and then setting the Marker ID and Marker size, mm as appropriate for the specific application. We strongly recommend measuring the actual marker by hand before adding an entry for it to [stretch_marker_dict.yaml](https://github.com/hello-robot/stretch_ros2/blob/humble/stretch_core/config/stretch_marker_dict.yaml).
We select marker ID numbers using the following ranges.
Every Python ROS [Node](http://wiki.ros.org/Nodes) will have this declaration at the top. The first line makes sure your script is executed as a Python script.
Every Python ROS [Node](http://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html) will have this declaration at the top. The first line makes sure your script is executed as a Python script.
This example aims to provide instructions on how to filter scan messages.
For robots with laser scanners, ROS provides a special Message type in the [sensor_msgs](https://github.com/ros2/common_interfaces/tree/iron/sensor_msgs) package called [LaserScan](https://github.com/ros2/common_interfaces/blob/iron/sensor_msgs/msg/LaserScan.msg) to hold information about a given scan. Let's take a look at the message specification itself:
For robots with laser scanners, ROS provides a special Message type in the [sensor_msgs](https://github.com/ros2/common_interfaces/tree/humble/sensor_msgs) package called [LaserScan](https://github.com/ros2/common_interfaces/blob/humble/sensor_msgs/msg/LaserScan.msg) to hold information about a given scan. Let's take a look at the message specification itself:
```{.bash .no-copy}
# Laser scans angles are measured counter clockwise,
@ -109,7 +109,7 @@ Now let's break the code down.
```python
#!/usr/bin/env python3
```
Every Python ROS [Node](http://wiki.ros.org/Nodes) will have this declaration at the top. The first line makes sure your script is executed as a Python script.
Every Python ROS [Node](http://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html) will have this declaration at the top. The first line makes sure your script is executed as a Python script.
Every Python ROS [Node](http://wiki.ros.org/Nodes) will have this declaration at the top. The first line makes sure your script is executed as a Python script.
Every Python ROS [Node](http://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html) will have this declaration at the top. The first line makes sure your script is executed as a Python script.
Every Python ROS [Node](http://wiki.ros.org/Nodes) will have this declaration at the top. The first line makes sure your script is executed as a Python script.
Every Python ROS [Node](http://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html) will have this declaration at the top. The first line makes sure your script is executed as a Python script.
In this example, we will review a Python script that prints out the positions of a selected group of Stretch joints. This script is helpful if you need the joint positions after you teleoperated Stretch with the Xbox controller or physically moved the robot to the desired configuration after hitting the run stop button.
If you are looking for a continuous print of the joint states while Stretch is in action, then you can use the [ros2 topic command-line tool](https://docs.ros.org/en/iron/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Topics/Understanding-ROS2-Topics.html) shown in the [Internal State of Stretch Tutorial](https://github.com/hello-robot/stretch_tutorials/blob/master/ros2/internal_state_of_stretch.md).
If you are looking for a continuous print of the joint states while Stretch is in action, then you can use the [ros2 topic command-line tool](https://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Topics/Understanding-ROS2-Topics.html) shown in the [Internal State of Stretch Tutorial](https://github.com/hello-robot/stretch_tutorials/blob/master/ros2/internal_state_of_stretch.md).
Begin by starting up the stretch driver launch file.
@ -9,7 +9,7 @@ Begin by starting up the stretch driver launch file.
ros2 launch stretch_core stretch_driver.launch.py
```
You can then hit the run-stop button (you should hear a beep and the LED light in the button blink) and move the robot's joints to a desired configuration. Once you are satisfied with the configuration, hold the run-stop button until you hear a beep. Then run the following command to execute the [joint_state_printer.py](https://github.com/hello-robot/stretch_tutorials/blob/iron/stretch_ros_tutorials/joint_state_printer.py) which will print the joint positions of the lift, arm, and wrist. In a new terminal, execute:
You can then hit the run-stop button (you should hear a beep and the LED light in the button blink) and move the robot's joints to a desired configuration. Once you are satisfied with the configuration, hold the run-stop button until you hear a beep. Then run the following command to execute the [joint_state_printer.py](https://github.com/hello-robot/stretch_tutorials/blob/humble/stretch_ros_tutorials/joint_state_printer.py) which will print the joint positions of the lift, arm, and wrist. In a new terminal, execute:
```{.bash .shell-prompt}
cd ament_ws/src/stretch_tutorials/stretch_ros_tutorials/
@ -130,7 +130,7 @@ Now let's break the code down.
#!/usr/bin/env python3
```
Every Python ROS [Node](https://docs.ros.org/en/iron/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html) will have this declaration at the top. The first line makes sure your script is executed as a Python3 script.
Every Python ROS [Node](http://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html) will have this declaration at the top. The first line makes sure your script is executed as a Python3 script.
In this example, we will review a Python script that prints and stores the effort values from a specified joint. If you are looking for a continuous print of the joint state efforts while Stretch is in action, then you can use the [ros2 topic command-line tool](https://docs.ros.org/en/iron/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Topics/Understanding-ROS2-Topics.html) shown in the [Internal State of Stretch Tutorial](https://github.com/hello-robot/stretch_tutorials/blob/master/ros2/internal_state_of_stretch.md).
In this example, we will review a Python script that prints and stores the effort values from a specified joint. If you are looking for a continuous print of the joint state efforts while Stretch is in action, then you can use the [ros2 topic command-line tool](https://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Topics/Understanding-ROS2-Topics.html) shown in the [Internal State of Stretch Tutorial](https://github.com/hello-robot/stretch_tutorials/blob/master/ros2/internal_state_of_stretch.md).
@ -12,7 +12,7 @@ Begin by running the following command in a terminal.
ros2 launch stretch_core stretch_driver.launch.py
```
There's no need to switch to the position mode in comparison with ROS1 because the default mode of the launcher is this position mode. Then run the [effort_sensing.py](https://github.com/hello-robot/stretch_tutorials/blob/iron/stretch_ros_tutorials/effort_sensing.py) node. In a new terminal, execute:
There's no need to switch to the position mode in comparison with ROS1 because the default mode of the launcher is this position mode. Then run the [effort_sensing.py](https://github.com/hello-robot/stretch_tutorials/blob/humble/stretch_ros_tutorials/effort_sensing.py) node. In a new terminal, execute:
```{.bash .shell-prompt}
cd ament_ws/src/stretch_tutorials/stretch_ros_tutorials/
@ -175,13 +175,14 @@ if __name__ == '__main__':
```
### The Code Explained
This code is similar to that of the [multipoint_command](https://github.com/hello-robot/stretch_tutorials/blob/iron/stretch_ros_tutorials/multipoint_command.py) and [joint_state_printer](https://github.com/hello-robot/stretch_tutorials/blob/iron/stretch_ros_tutorials/joint_state_printer.py) node. Therefore, this example will highlight sections that are different from those tutorials. Now let's break the code down.
This code is similar to that of the [multipoint_command](https://github.com/hello-robot/stretch_tutorials/blob/humble/stretch_ros_tutorials/multipoint_command.py) and [joint_state_printer](https://github.com/hello-robot/stretch_tutorials/blob/humble/stretch_ros_tutorials/joint_state_printer.py) node. Therefore, this example will highlight sections that are different from those tutorials. Now let's break the code down.
```python
#!/usr/bin/env python3
```
Every Python ROS [Node](https://docs.ros.org/en/iron/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html) will have this declaration at the top. The first line makes sure your script is executed as a Python3 script.
Every Python ROS [Node](http://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html
) will have this declaration at the top. The first line makes sure your script is executed as a Python3 script.
```python
import rclpy
@ -199,7 +200,7 @@ from control_msgs.action import FollowJointTrajectory
from trajectory_msgs.msg import JointTrajectoryPoint
```
You need to import rclpy if you are writing a ROS [Node](https://docs.ros.org/en/iron/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html). Import the `FollowJointTrajectory` from the `control_msgs.action` package to control the Stretch robot. Import `JointTrajectoryPoint` from the `trajectory_msgs` package to define robot trajectories. The `hello_helpers` package consists of a module that provides various Python scripts used across [stretch_ros](https://github.com/hello-robot/stretch_ros2). In this instance, we are importing the `hello_misc` script.
You need to import rclpy if you are writing a ROS [Node](http://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html). Import the `FollowJointTrajectory` from the `control_msgs.action` package to control the Stretch robot. Import `JointTrajectoryPoint` from the `trajectory_msgs` package to define robot trajectories. The `hello_helpers` package consists of a module that provides various Python scripts used across [stretch_ros](https://github.com/hello-robot/stretch_ros2). In this instance, we are importing the `hello_misc` script.
@ -28,7 +28,7 @@ ros2 run rviz2 rviz2 -d /home/hello-robot/ament_ws/src/stretch_tutorials/rviz/pe
```
## Capture Image with Python Script
In this section, we will use a Python node to capture an image from the [RealSense camera](https://www.intelrealsense.com/depth-camera-d435i/). Execute the [capture_image.py](stretch_ros_tutorials/capture_image.py) node to save a .jpeg image of the image topic `/camera/color/image_raw`. In a terminal, execute:
In this section, we will use a Python node to capture an image from the [RealSense camera](https://www.intelrealsense.com/depth-camera-d435i/). Execute the [capture_image.py](https://github.com/hello-robot/stretch_tutorials/blob/humble/stretch_ros_tutorials/capture_image.py) node to save a .jpeg image of the image topic `/camera/color/image_raw`. In a terminal, execute:
```{.bash .shell-prompt}
cd ~/ament_ws/src/stretch_tutorials/stretch_ros_tutorials
@ -99,7 +99,7 @@ Now let's break the code down.
```python
#!/usr/bin/env python3
```
Every Python ROS [Node](https://docs.ros.org/en/iron/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html) will have this declaration at the top. The first line makes sure your script is executed as a Python3 script.
Every Python ROS [Node](http://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html) will have this declaration at the top. The first line makes sure your script is executed as a Python3 script.
```python
import rclpy
@ -108,7 +108,7 @@ import os
import cv2
```
You need to import `rclpy` if you are writing a ROS [Node](https://docs.ros.org/en/iron/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html). There are functions from `sys`, `os`, and `cv2` that are required within this code. `cv2` is a library of Python functions that implements computer vision algorithms. Further information about cv2 can be found here: [OpenCV Python](https://www.geeksforgeeks.org/opencv-python-tutorial/).
You need to import `rclpy` if you are writing a ROS [Node](http://docs.ros.org/en/humble/Tutorials/Beginner-CLI-Tools/Understanding-ROS2-Nodes/Understanding-ROS2-Nodes.html). There are functions from `sys`, `os`, and `cv2` that are required within this code. `cv2` is a library of Python functions that implements computer vision algorithms. Further information about cv2 can be found here: [OpenCV Python](https://www.geeksforgeeks.org/opencv-python-tutorial/).
hello-jesus
8 months ago