@ -8,7 +8,7 @@ Begin by starting up the stretch driver launch file.
# Terminal 1
roslaunch stretch_core stretch_driver.launch
```
To activate the [RealSense camera](https://wiki.seeedstudio.com/ReSpeaker_Mic_Array_v2.0/) and publish topics to be visualized, run the following launch file in a new terminal.
To activate the [RealSense camera](https://www.intelrealsense.com/depth-camera-d435i/) and publish topics to be visualized, run the following launch file in a new terminal.
Next, run the stretch ArUco launch file which will bring up the [detect_aruco_markers](https://github.com/hello-robot/stretch_ros/blob/master/stretch_core/nodes/detect_aruco_markers) node.
```bash
# Terminal 3
roslaunch stretch_core stretch_aruco.launch
```
Within this tutorial package, there is an RViz config file with the topics for transform frames in the Display tree. You can visualize these topics and the robot model by running the command below in a new terminal.
@ -111,7 +107,6 @@ class LocateArUcoTag(hm.HelloNode):
"""
self.joint_state = msg
def send_command(self, command):
'''
Handles single joint control commands by constructing a FollowJointTrajectoryGoal
@ -142,7 +137,6 @@ class LocateArUcoTag(hm.HelloNode):
self.trajectory_client.send_goal(trajectory_goal)
self.trajectory_client.wait_for_result()
def find_tag(self, tag_name='docking_station'):
"""
A function that actuates the camera to search for a defined ArUco tag
@ -194,7 +188,6 @@ class LocateArUcoTag(hm.HelloNode):
rospy.loginfo('Searching for docking ArUco tag.')
pose = self.find_tag("docking_station")
if __name__ == '__main__':
try:
node = LocateArUcoTag()
@ -226,7 +219,7 @@ from trajectory_msgs.msg import JointTrajectoryPoint
from geometry_msgs.msg import TransformStamped
```
You need to import rospy if you are writing a ROS Node. Import other python modules needed for this node. Import the FollowJointTrajectoryGoal from the [control_msgs.msg](http://wiki.ros.org/control_msgs) package to control the Stretch robot. Import JointTrajectoryPoint from the [trajectory_msgs](http://wiki.ros.org/trajectory_msgs) package to define robot trajectories. The [hello_helpers](https://github.com/hello-robot/stretch_ros/tree/master/hello_helpers) package consists of a module the provides various Python scripts used across [stretch_ros](https://github.com/hello-robot/stretch_ros). In this instance we are importing the hello_misc script.
You need to import `rospy` if you are writing a ROS [Node](http://wiki.ros.org/Nodes). Import other python modules needed for this node. Import the `FollowJointTrajectoryGoal` from the [control_msgs.msg](http://wiki.ros.org/control_msgs) package to control the Stretch robot. Import `JointTrajectoryPoint` from the [trajectory_msgs](http://wiki.ros.org/trajectory_msgs) package to define robot trajectories. The [hello_helpers](https://github.com/hello-robot/stretch_ros/tree/master/hello_helpers) package consists of a module the provides various Python scripts used across [stretch_ros](https://github.com/hello-robot/stretch_ros). In this instance we are importing the `hello_misc` script.
```python
def __init__(self):
@ -241,7 +234,6 @@ def __init__(self):
self.joint_state = None
```
The `LocateArUcoTag` class inherits the `HelloNode` class from `hm` and is instantiated.
Set up a subscriber with `rospy.Subscriber('/stretch/joint_states', JointState, self.joint_states_callback)`. We're going to subscribe to the topic "*stretch/joint_states*", looking for `JointState` messages. When a message comes in, ROS is going to pass it to the function `joint_states_callback()` automatically.
Provide the minimum and maximum joint positions for the head pan. These values are needed for sweeping the head to search for the ArUco tag. We also define the number of steps for the sweep, then create the step size for the head pan joint.
```python
@ -262,7 +253,6 @@ self.min_tilt_position = -0.75
self.tilt_num_steps = 3
self.tilt_step_size = pi/16
```
Set the minimum position of the tilt joint, the number of steps, and the size of each step.
Assign *trajectory_goal* as a `FollowJointTrajectoryGoal` message type. Then extract the string value from the `joint` key. Also, assign *point* as a `JointTrajectoryPoint` message type.
```python
@ -307,14 +295,12 @@ if 'delta' in command:
new_value = joint_value + delta
point.positions = [new_value]
```
Check to see if `delta` is a key in the command dictionary. Then get the current position of the joint and add the delta as a a new position value.
```python
elif 'position' in command:
point.positions = [command['position']]
```
Check to see if `position`is a key in the command dictionary. Then extract the position value.
Then `trajectory_goal.trajectory.points` is defined by the positions set in *point*. Specify the coordinate frame that we want (*base_link*) and set the time to be now. Make the action call and send the goal. The last line of code waits for the result before it exits the python script.
Use a try-except block to look up the transform between the *base_link* and requested ArUco tag. Then publish and return the `TransformStamped` message.
Create a StaticTranformBoradcaster Node. Also, start a tf buffer that will store the tf information for a few seconds.Then set up a tf listener, which will subscribe to all of the relevant tf topics, and keep track of the information. Include `rospy.sleep(1.0)` to give the listener some time to accumulate transforms.
```python
@ -418,7 +395,6 @@ if __name__ == '__main__':
except KeyboardInterrupt:
rospy.loginfo('interrupt received, so shutting down')
```
Declare `LocateArUcoTag` object. Then run the `main()` method.
The Stretch robot is equipped with the Intel RealSense D435i camera, an essential component that allows the robot to measure and analyze the world around it. In this tutorial, we are going to showcase how to visualize the various topics published from the camera.
The Stretch robot is equipped with the [Intel RealSense D435i camera](https://www.intelrealsense.com/depth-camera-d435i/), an essential component that allows the robot to measure and analyze the world around it. In this tutorial, we are going to showcase how to visualize the various topics published from the camera.
Begin by checking out the [feature/upright_camera_view](https://github.com/hello-robot/stretch_ros/tree/feature/upright_camera_view) branch in the stretch_ros repository. The configuration of the camera results in the images being displayed sideways. Thus, this branch publishes a new topic that rotates the raw image upright.
Begin by checking out the [feature/upright_camera_view](https://github.com/hello-robot/stretch_ros/tree/feature/upright_camera_view) branch in the [stretch_ros](https://github.com/hello-robot/stretch_ros) repository. The configuration of the camera results in the images being displayed sideways. Thus, this branch publishes a new topic that rotates the raw image upright.
```bash
cd ~/catkin_ws/src/stretch_ros/stretch_core
@ -15,7 +15,7 @@ Then run the stretch driver launch file.
roslaunch stretch_core stretch_driver.launch
```
To activate the RealSense camera and publish topics to be visualized, run the following launch file in a new terminal.
To activate the [RealSense camera](https://www.intelrealsense.com/depth-camera-d435i/) and publish topics to be visualized, run the following launch file in a new terminal.
Alan G. Sanchez
2 years ago