Using the pressure_control ROS drivers

1. Manual pressure control
2. Build Trajectories
3. Prepare to Run the Pressure Controller
4. Run Trajectories Manually
5. Send Trajectories in Realtime

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This driver is split into two ROS packages:

• pressure_trajectory_ros is where trajectories are set up, built, and stored for execution
• pressure_control_ros is the main driver that actually interfaces with the pressure control hardware

Manual pressure control

roslaunch pressure_controller_ros set_setpoint.launch

Build Trajectories

To build a pressure trajectory, you can either discretize a periodic waveform, or use a set of waypoints.

Set Up a Trajectory

1. In the “pressure_trajectory_ros” package, browse the “traj_setup” folder. This is where you can set up trajectories to be built.
2. In the “examples” folder, open “planar2seg_demo.yaml”. This example will produce a triangle wave with some prefix and suffix to that trajectory.
3. Examine the “settings” section of the file. Here we note that the trajectory is of type “waveform” and it is not designed to be wrapped (repeated over and over).
4. Examine the “config” section of the file. Here we notice a few things:
   • Only channels 1 and 2 are active
   • The waveform is a triangle wave of frequency 0.25 Hz
   • The waveform is repeating two times, and each cycle is discretized into 90 sub-samples.
5. Next, we can see the “setpoints” section has some prefix waypoints (which will be executed before the waveform), and suffix waypoints (executed after the waveform).

Build a Trajectory

Building a trajectory is a single command through roslaunch:

roslaunch pressure_trajectory_ros build_traj.launch profile:=example/planar2seg_demo

Note that you don’t need to include the file extension “.yaml’

Prepare to Run the Pressure Controller

To begin running the pressure controller, use the following command:

roslaunch pressure_controller_ros bringup.launch profile:=YOUR_CONFIG_PROFILE

In the “config” folder of the “pressure_control_ros” package, you can set up hardware configurations. the “DEBUG.yaml” configuration is a good place to start.

Note that you don’t need to include the file extension “.yaml’

Run Trajectories Manually

1. Make sure you have started the pressure control interface:

roslaunch pressure_controller_ros bringup.launch profile:=DEBUG

1. In a new terminal, upload the trajectory:

roslaunch pressure_controller_ros load_traj.launch profile:=example/planar2seg_demo

1. Start running the trajectory:

roslaunch pressure_controller_ros run_traj.launch

Send Trajectories in Realtime

This is fully implemented now. The implementation is based on the ur_modern_driver for Universal Robots. Documentation is comming soon. For now, feel free to check out the source code and the live_traj_follower launch file. In addition to this rosnode, the realtime trajectory follow has a python library that can be imported in other ros projects, ans seen in my Hand+Arm Package

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