Willow Garage has developed an autonomous robot control architecture employing the Extensible Universal Remote Operations Planning Architecture (EUROPA). Recently, a PR2 robot navigated in a dynamic indoor environment autonomously for two days in a row, each day doing PI kilometers. The only intervention was to plug in and unplug the robot at its request. TREX (using EUROPA) provided a set of way-points, a charging station, and a high-level goal to pursue way-points selected at random, indefinitely. The robot would reactively pre-empt goals in order to recharge based on a simple check of battery levels. This would prompt it to navigate to the charging station and initiate a behavior to recharge itself (which involved e-mailing for help to plug in and unplug when done). When recharged, it would resume the pre-empted goal. It also handles situations like re-planning after a failure, or terminating goals that have run out of time. The model/system includes the ability to handle over-subscribed problems, but this is not utilized. Lower-level controllers integrated path planners for global path planning and trajectory controllers for velocity control. TREX and EUROPA ran continuously for about 24 hours without a problem.
BACKGROUND: The Extensible Universal Remote Operations Planning Architecture (EUROPA) was developed at NASA Ames Research Center, and was made available under NASA Open Source Agreement (NOSA). EUROPA is used for a variety of different mission planning and scheduling applications, and has been demonstrated in advanced technology demonstrations for control of autonomous robots and spacecraft.
PROGRAM FUNDING: ESMD, MTP
COLLABORATOR: Willow Garage
Contact: C. McGann (Willow Garage); J. Barreiro, Jeremy Frank (NASA Ames)