1. Computing & Information Sciences Kansas State University Cooperative Robotic Simulator Environment Simulator Masters’ Report Scott J. Harmon May 12, 2004 Cooperative Robotics Simulator Group

2. Computing & Information Sciences Kansas State University Outline Introduction  Overall system  Demo Environment Module  Main Loop  Map Component  Robot and Sensor Components Module Communications/Major Protocols  Robot Environment  Viewer Environment Future Work  Network improvements  Map improvements  Reflection

3. Computing & Information Sciences Kansas State University Overall System Architecture Multiple Modules written in Java:  Environment  Robot  Viewer  Control Panel  Communications

4. Computing & Information Sciences Kansas State University Overall System Architecture-2 [1]

5. Computing & Information Sciences Kansas State University Example Deployment

6. Computing & Information Sciences Kansas State University Demonstration

7. Computing & Information Sciences Kansas State University System Components

8. Computing & Information Sciences Kansas State University Environment Components

9. Computing & Information Sciences Kansas State University Environment Module Coordinates and drives the simulation  Main Loop using time-step based approach Models the virtual environment  Keeps track of positional and state information of all objects in the virtual environment

10. Computing & Information Sciences Kansas State University Environment - Main Loop Iterated for each time-step  Time-steps size is set at runtime Drives the simulation

11. Computing & Information Sciences Kansas State University Environment - Main Loop-2 1 waitForRobots(); 2 setState(STATE_ROBOTS); 3 sendObjectsToVRMLClients(); 4 currentTime = 0; 5 running = true; 6 setState(STATE_RUNNING); 7 while(running) { 8//get the event for this timestep from each Robot 9//lock the robotqueue 10synchronized(robots) { 11//This double-stepped get allows the stuff to travel here before I block trying to get it. 12for (int i = 0; i < robots.size(); i++) { 13EnvironmentObjectRobot robot = (EnvironmentObjectRobot) robots.get(i); 14robot.prepGetEvents(currentTime); 15} 16for (int i = 0; i < robots.size(); i++) { 17EnvironmentObjectRobot robot = (EnvironmentObjectRobot) robots.get(i); 18robot.queueEvents(); 19} 20} 21//process queue from front (top). 22processActionEventQueue(); 23//send out sensor readings to robots. 24processSensorEventQueue(); 25//add timestep to VRMLUpdates. 26for (int i = 0; i < viewerUpdateQueue.size(); i++) { 27((ViewerUpdateLocation)viewerUpdateQueue.get(i)).timestep = currentTime; 28} 29//send out VRMLUpdates to the VRML viewer 30sendViewerEvents(viewerUpdateQueue); 31currentTime++; 32try { 33Thread.sleep(steppausetime); 34} catch (InterruptedException e) {} 35 }

12. Computing & Information Sciences Kansas State University Communications between Modules Java Socket used  Each component connects on a pre-determined port to the Environment.  Serializable objects are sent over the Socket connection.

13. Computing & Information Sciences Kansas State University Robot Environment Protocol

14. Computing & Information Sciences Kansas State University Viewer Environment Protocol

15. Computing & Information Sciences Kansas State University Conclusions Simulator is distributable because of the modularity Modules communicate using protocols over a socket connection Environment module is responsible for orchestrating the simulation and for modeling the virtual environment.

16. Computing & Information Sciences Kansas State University Future Work There are three areas in the Environment module to improve:  Network  Map  Reflection

17. Computing & Information Sciences Kansas State University Future Work – Network Network is utilized for communications between modules Enhancements:  Optimize by reducing amount of communications  Improve latency  Fetch Robot commands in separate threads while previous commands are being evaluated

18. Computing & Information Sciences Kansas State University Future Work – Network-2 Example Protocol:

19. Computing & Information Sciences Kansas State University Future Work – Map Component Map Component in charge of modeling the virtual environment Enhancements:  Domain specific Map components  What physics needs to be modeled?  Collision Detection improvements  Java3D  Grid World (Change time into space)  Distribute  Can we distribute the maintenance of the virtual environment across multiple system?  Compound objects (grouping)  A robot might be made up of more than one geometric shape.

20. Computing & Information Sciences Kansas State University Future Work – Reflection Java Reflection allows the dynamic loading of classes by name Enhancements:  Make all sensors and effectors loaded dynamically by name  Allows us to add sensors and effectors without the need to modify the original code  Different Maps (virtual environment maintainer) loadable by name  Allows “pluggable” components

21. Computing & Information Sciences Kansas State University References [1] The Official Project website, http://www.cis.ksu.edu/~sdeloach/ai/projects/crsim.htm

22. Computing & Information Sciences Kansas State University Acknowledgements Committee:  Dr. DeLoach  Dr. Gustafson  Dr. Hsu Teammates:  Venkata Prashant Rapaka, Arun Prakash Ganesan, Esteban Guillen, and Aaron Chavez

23. Computing & Information Sciences Kansas State University Questions