Migration.md

yarpWholeBodyInterface 0.1 to 0.2

The yarpWholeBodyInterface version 0.2 depends upon wholeBodyInterface 0.2, which introduced many changes in the wholeBodyInterface. yarpWholeBodyInterface specific changes are discussed in this file. In 0.2 we aim at providing a generic interface to yarp-powered robot, removing any iCub specific software: most of the changes are related to this purpose.

Namespace change

The namespace for all the project changed from wbiIcub to yarpWbi

Relevant code changes

using namespace wbiIcub;

becomes

using namespace yarpWbi;

Headers names changes

The namespace for all the headers changed from icub related names to yarp related names

#include <wbiIcub/wholeBodyInterfaceIcub.h>

becomes

#include <yarpWholeBodyInterface/yarpWholeBodyInterface.h>

WBI Configuration files

In version 0.2, no robot information is hardcoded in the yarp-wholebodyinterface.

All information is now gather from appropriate configuration files. An example configuration file for iCubHeidelberg01 is available here: https://github.com/robotology/icub-main/blob/master/app/robots/iCubHeidelberg01/wholeBodyInterface.ini

The information in this configuration file is parsed to a yarp::os::Property object, and then passed to the interface throught the constructor or using the setYarpWbiProperties methods. This information is then used in the init() method, and it cannot be altered after the interface initialization.

Fof the modules in codyco-modules, the name of this configuration file is passed via a wbi_conf_file configuration option (with the default set to wholeBodyInterface.ini). Similarly in the wbi configuration file the name of the used urdf file is passed throught a urdf_file option. The actual location of this two files is then obtained throught the Yarp ResourceFinder.

You can get more information about the ResourceFinder in the official Yarp documentation:

• ResourceFinder Tutorials and Specification. Using the ResourceFinder we can exploit the robots directories, through which the user can use/install robot specific configuration files using the YARP_ROBOT_NAME enviromental variable.

Relevant code changes

 //--------------------------WHOLE BODY INTERFACE--------------------------
iCub::iDynTree::iCubTree_version_tag icub_version;
iCubVersionFromRf(rf,icub_version);
robotInterface = new icubWholeBodyInterface(moduleName.c_str(), robotName.c_str(),icub_version);

becomes (just an example, details can vary):

//--------------------------WHOLE BODY INTERFACE--------------------------
yarp::os::Property yarpWbiOptions;
//Get wbi options from the canonical file
if( !rf.check("wbi_conf_file") )
{
    fprintf(stderr,"[ERR] locomotionControl: impossible to open wholeBodyInterface: wbi_conf_file option missing");
}
std::string wbiConfFile = rf.findFile("wbi_conf_file");
yarpWbiOptions.fromConfigFile(wbiConfFile);
//Overwrite the robot parameter that could be present in wbi_conf_file
yarpWbiOptions.put("robot",robotName);
robotInterface = new yarpWholeBodyInterface(moduleName.c_str(), yarpWbiOptions);

ID Lists

In version 0.1, the list of IDs where hard-coded at compile time, for example in the ICUB_MAIN_JOINTS constant list. In version 0.2, list of IDs are loaded at configuration time from configuration files.

Again, for an example of configuration file check: https://github.com/robotology/icub-main/blob/d4b6c70076876bc6ce2947b1a1969101328b1af5/app/robots/iCubHeidelberg01/wholeBodyInterface.ini

We started using "pseudo" standard names for joint ID lists, with some semantical meaning attached. For now we are using:

• ROBOT_TORQUE_CONTROL_JOINTS : the set of all joints in the robot for which torque control is enabled.
• ROBOT_DYNAMIC_MODEL_JOINTS : the set of joints typicaly used for the dynamical model of the robot (i.e. typically things like the fingers are not included in this list).

Relevant code changes

robotInterface->addJoints(ICUB_MAIN_JOINTS);

becomes (just an example, details can vary):

IDList RobotMainJoints;
std::string RobotMainJointsListName = "ROBOT_MAIN_JOINTS";
if( !loadIdListFromConfig(RobotMainJointsListName,yarpWbiOptions,RobotMainJoints) )
{
    fprintf(stderr, "[ERR] locomotionControl: impossible to load wbiId joint list with name %s\n",RobotMainJointsListName.c_str());
}
robotInterface->addJoints(RobotMainJoints);

Drop is*Simulator calls

isICubSimulator and isRobotSimulator have been dropped, being hardcoded function that checked just the robotname. They can be substituted by alternative wbi configuration files for simulator that lack some sensors, or eventually checks in the user code.

iCub naming changes

Even if this is not something directly related to the yarp-wholebodyinterface, it is worth mentioning that some names in the iCub models changed, for more information check robotology/icub-main#57 . One of the most important changes is that the two links l_shank and r_shank are now named l_leg and r_leg.