Using Sun’s Java Real-Time System to Manage Behavior-Based Mobile Robot Controllers

Table 1

Task threads used in the robot architecture.

Tasks	Description	Provides	Requires
DATAPOSUPDATE	Sends movement commands to the robot and receives updated position information.	PositionData
DATALASERUPDATE	Gets the laser readings from the URG laser.	LaserData
WAYPOINTPLANNER	A high-level behavior that moves the robot through a series of predefined waypoints using a path created by the DIJKSTRAPLANNER.		PositionData,; LaserData,; PathData
LASERAVOIDOBSTACLES	Responds to obstacles sensed by the laser, via DATALASERUPDATE, by slowing down the robot and turning away from the obstacle, via DATAPOSUPDATE.		LaserData
OCCUPANCYGRIDMAP [27]	Uses the position and laser data reported by DATAPOSUPDATE and DATALASERUPDATE and maintains an occupancy grid map. The map tracks unknown, open, and occupied space.	MapData	LaserData; PositionData
DIJKSTRAPLANNER [28]	Takes goal position requests and maintains a path from the current position to the closest goal. Multiple goals may be added and the requester must remove the goal when it is no longer valid (has been reached).	PathData	MapData