Page - 155 - in Proceedings - OAGM & ARW Joint Workshop 2016 on "Computer Vision and Robotics“

Also,goalposeshadtobesentfromROSnodesandSMACHtobeprocessedbyMIRA.Thisfunction wasimplementedasaROSactionserverfromwhichaMIRAnavigationtaskincludingposition,final orientation, and preferred driving direction subtasks -with their corresponding tolerances- is started. Thisway,anavigationtask toagivengoalcanbepreemptedfromthebehaviorsideandthenecessary feedback about the task status is provided by the actionlib server. The interface to start the action is the same as when sending a goal to ROS MoveBase action server, and the provided feedback is also translated tosimilar terms. Interfaces fordiscretemotioncommands(distance tomove,angle to turn) were also created to run in a separated ROS thread based on the distance mode experimental feature ofMIRA. Anotheractionwascreatedinorder tostartandinterruptdockingonandofffromthechargingstation. Theseprocedures were implemented internallywithin MIRA. Fig. 1 shows a simplified overview of the system architecture, including the most important modules anddataflowswithregard tonavigationrelated tasks. Moredetailsabout these tasksandmethodsare included inSection4.. interfaces_mira ROS Smach behavior state machine Skeleton detection, gestures recognition MMUI head position and RGB-D data FindObject CallRobot LocateUser PickUpRecharge goal pose action dist/ang commands docking on/off action top scan bottom scan obs scan RGB-D data GoTo actions feedback other data localization pose local map path tasks feedback low level information virtual scans navigation tasks distance mode commands (dist/ang) docking on/off tasks localization reset Other ROS nodes Other arm Figure 1. System components overview, focusing on navigation related tasks and modules (other details omitted fortheshakeofclarity). ROSSmachbehaviorstatemachinescaninteractwithMIRAthroughthe interfacesnode directlyor through othernodes. Themappingprocess tookplaceinadvance,duringthesetupphaseateachnewtrialsite. Forbuilding newmaps,weused theROSimplementationofGmapping[8]andconverted thegeneratedmaps into theMIRAcorresponding format. 155