marimbabot_simulation

Simulation package

Overview

The simulation consists of a Gazebo world with a Marimbabot model, a node to detect contacts and generate MIDI, and optionally PlotJuggler to view contact velocities. The planning node is launched as well to allow the user to play the simulation using the action server.

Launch files

There are the following launch files:

• marimbabot_gazebo.launch: Launches the simulation in Gazebo.
• marimbabot_full_sim.launch: Launches the simulation in Gazebo, as well as nodes to detect contacts, publish the contact points, generate MIDI, and optionally launch PlotJuggler to view contact velocities. This is the recommended launch file to use.

The PlotJuggler can be toggled on/off by setting the appropriate bool flag in the if block in the the launch file.

How to run

First, make sure you have completed the steps in the main README and therefore have a working environment.

Launch the simulation with the following command:

roslaunch marimbabot_simulation marimbabot_full_sim.launch

The simulation can play any piece, and therefore needs to be fed a note string either manually using the action server, or using the sound_pad.py script in the marimbabot_planning/scripts package folder. E.g. to launch the Sound Pad script:

rosrun marimbabot_planning sound_pad.py

Contact detection

The main simulation launchfile also launches a node (detect_bar_contact.py) to detect bar hits by applying a threshold to the bar joint velocities, and then write the detected notes to a MIDI file at the end of the simulation.

MIDI generation

The simulation will record all bar hits (starting from the first hit to avoid a long silent interval in the beginning) and save them as a MIDI file in the marimbabot_simulation/midi package folder with current datetime as name. If the marimbabot_simulation directory cannot be found using rospack find, then the script falls back to the current directory. In any case, the MIDI directory will be logged to the output stream.

The MIDI file can be played as follows:

fluidsynth /usr/share/sounds/sf2/FluidR3_GM.sf2 <PATH/TO/MIDI_FILE>.midi -a alsa

In the above command, replace the path and <FILENAME> with the name of the MIDI file.

To convert a MIDI file to MP3, use the following command template:

fluidsynth -l -T raw -F - /usr/share/sounds/sf2/FluidR3_GM.sf2 <PATH/TO/MIDI_FILE>.midi | twolame -b 256 -r - <NAME>.mp3