#Pacer Project Repository by Sam Zapolsky @ the Positronics Lab

This repository hosts code for Pacer an open source robot locomotion library for simulated and physical legged robots.

For more information, check out the wiki.

##Dependencies

####Required

• Ravelin
• Moby
• Boost

####Optional

• OpenSceneGraph
• DXL
• SDL (permits joystick control)

Quick start to using Pacer

Building

mkdir release; cd release;

If Ravelin and Moby are installed on your system:

cmake ..

otherwise

cmake -DMOBY_INCLUDE_DIR="/path/to/moby/include" -DMOBY_LIBRARY="/path/to/moby/lib/libMoby.so" -DMOBY_LIBRBRY_DIR="/path/to/moby/lib" -DMOBY_LIBRBRY_DIRS="/path/to/moby/lib" -DRAVELIN_INCLUDE_DIR="/path/to/ravelin/include" -DRAVELIN_LIBRARY="/path/to/ravelin/lib/libRavelin.so" -DRAVELIN_LIBRBRY_DIR="/path/to/ravelin/lib" -DRAVELIN_LIBRBRY_DIRS="/path/to/ravelin/lib" -DUSE_OSG_DISPLAY=ON -DCMAKE_BUILD_TYPE=RELEASE ..;

and then build:

make -j <cores> all

Setup

in the project base directory, run:

source setup.sh

This will point Gazebo and Pacer to the models and build directories. setup.sh sets environment vars:

• `PACER_MODEL_PATH` points to model directories where `Pacer` will import the robot kinematic and inertial information (`Pacer` does NOT get model information from the simulator)
  

  • `PACER_COMPONENT_PATH` points to the directory where the perception, planning, and control (Component) plugins have been built.
    

  • `PACER_SIMULATOR_PATH` points to the directory where the simulator (interface) plugins have been built.
    

  • `GAZEBO_MODEL_PATH` is a `:` delimited list of paths to where the gazebo models `sdf` and their config files reside.
    

  • `GAZEBO_PLUGIN_PATH` is a `:` delimited list of paths to where the gazebo model plugins have been built, including our gazebo plugin: `libPacerGazeboPlugin.so` has been built
    

R. Links (Quadruped) Demo

remember to run:

source /build/dir/setup.sh

then navigate to the demo working directory for a trotting gait:

cd ${PACER_HOME}/Example/Demo/Trot

Write the environment paths into the demo XML files: (NOTE: this command writes filename.xml.in to filename.xml)

${PACER_SCRIPT_PATH}/setup-tests.sh *.in

starting in Moby:

then start Moby while pointing at the Pacer Moby simulator plugin:

moby-driver -r -s=0.001 -p=${PACER_SIMULATOR_PATH}/libPacerMobyPlugin.so model.xml

This will start the robot R. Links 'trotting' on a plane in the Moby simulator with visualization turned on.

starting in Gazebo:

then start Gazebo while pointing at the links world file:

gazebo ${PACER_MODEL_PATH}/links/model.world

Gazebo will see that the model file ${PACER_MODEL_PATH}/links/model.sdf uses to controller libPacerGazeboPlugin.so, it will find this controller in directory ${GAZEBO_PLUGIN_PATH}/ which was exported by running setup.sh.

• NOTE: This could be built as libPacerGazeboPlugin.dylib on an OSX system be sure to change the name of the plugin in ${PACER_MODEL_PATH}/links/model.sdf if Gazebo can't find any model plugin.

This will start the robot R. Links 'trotting' on a plane in the Gazebo simulator.

NOTE: Pacer will read the file vars.xml in the working directory on startup. This file sets parameters in all controller plugins, as well as telling Pacer which plugins to load.

##Usage

Access the library by using the examples found in the examples directory:

EXAMPLE	DESCRIPTION
simulator plugins	Moby & Gazebo controller plugins communicte with Pacer
models	Pre-implemented robot models and vars files (see models/README.md)
component plugins	Discrete control modules for the robot. Add capabilites to Pacer by adding plugins here.

Exporting Data to MATLAB

Logs are either output to terminal or written to the file: "out.log" in the run directory. Running Pacer will overwrite the current instance of "./out.log"

Vectors and Matrices output is readable in Matlab. The examples in scripts demonstrate exporting output from Pacer's logs to MATLAB readable space delimited files.

File Structure

FILE/DIRECTORY	DESCRIPTION
CMakeLists.txt	CMake build file for Pacer
Example	Use cases and helpful files for using Pacer
src	Pacer core source code and, Header files for calling functions in Pacer (does not do much without components)
Plugin	Everything needed to actually use Pacer: Components plug into Pacer and serve as perception, planning, control, or data collection modules; Plugins built in Simulator plug Pacer into a simulator, currently Gazebo and Moby are supported.