Exploring with Lego Robots

1. Exploring withLego Robots Daniel Limbrick(Texas A&M University) Emily Sherrill(Tennessee Tech University)

2. Challenge Final Robot Design Mid-Summer Summary Progress of Second Term PC/Robot Simulation Maze Frame Controller Robot Movement Circuit Problems Conclusion Final Report Overview:

3. The Challenge: • Use a Bluetooth device to adapt a Lego Mindstorms robot for wireless communication • Using the Java programming language, make the robot explore a maze and communicate the layout of the maze back to a computer • Create a controller to allow the robot to be driven from the computer screen

4. Final Design of Our Lego Robot • Two Motors • Two Rotation Sensors • One Touch Sensor • RCX Lego Brick

5. Mid-Summer Summary • Accomplishments • Straight line travel • Maze Mapping Algorithm • Go-to-Point Algorithm • DLL Protocol • Untested Simulator

6. Mid-Summer Summary • Problems • Wheels stick, slip, or slide depending on surface • Rotations are not always accurate or consistent • Different motor strengths • Touch sensor activation

7. Progress of Second Term • Tasks Remaining at Mid-Summer Report • Making robot movement more accurate • Sending/receiving information from actual robot • Completing user-click point travel • Expanding the Controller • Accomplishments during Second Term • Simulation of PC/Robot Communication • User-Click Point Travel/Controller • Robot Movement • Sending/Receiving from actual robot

8. Simulation of PC/Robot Communication • Designed to locate flaws in the algorithm logic and in the program coding • After correcting initial errors, the simulation works successfully for both the maze mapping algorithm and the go-to-point algorithm • Converted string movement commands to byte movement commands, so that the command transfers from robot to PC are completed with minimal chance of data alteration or lose.

9. Maze Frame • Creates a visual representation of the maze • Maze Mapping Display • Updates the display of the maze as the robot discovers the layout during the Maze Mapping Algorithm • Depicts the robot view of the maze

10. MazeFrame • Go-to-Point Display • Displays the moves that the robot will perform before it actually starts the processing of the Go-to-Point algorithm commands

11. Controller • User-Point Click Travel • Uses the MazeFrame class with a MouseListener • When the user clicks on a point in the graphical representation of the maze, the MouseListener determines where the click occurred, translates that point into the equivalent maze dimension point, and then send the point to the go-to-point algorithm • Controller Expansion • Allows the user to move the robot using the arrow keys • Cancelled due to time

12. Examples of Test Mazes

13. Starting at any Point

14. Robot Movement • Improved accuracy of the rotations (still not 100%) • RobotLejos class • Download onto robot • Contains all robot movement methods • Methods in class can be called by PC

15. Circuit • Tested the Bluetooth circuit that will be used on the robot by linking it to the computer. The circuit generated values and transmitted it to the computer's serial port. The output was displayed on the HyperTerminal. • Accuracy of the output was dependant upon the voltage from the battery and the resistance of the potentiometer. • Must be properly calibrated before use

16. Problems • Discovered that scrolling up in the command line window while the program is running causes a back up in the communication port • With strings: becomes one long continuous string • With bytes: causes the program to miss bytes • Previous robot movement issue still exist • The first DLL would not release control over the communication serial port for the following DLL to have access to it

17. Problems • Problems with the circuit • Overloads LEDs located at the front of the RCX bricks. • Originally used wrong capacitor • Excess noise sent through the serial port causes errors in the DLL’s ability to receive information accurately. • As battery power fluctuates, the potentiometer has to be recalibrated.

18. Conclusion and Improvements • Successfully simulated entire project • Partially demonstrated project with robot • Future considerations • Using wheels with less friction (robot movement accuracy) • Using the new RCX brick with built-in Bluetooth capability (reliable communication)

19. Our Poster

20. Exploring withLego Robots Daniel Limbrick(Texas A&M University) Emily Sherrill(Tennessee Tech University)

21. Thanks: • Grad Student Advisor: Daniel B. • Dr. Karsai • Ryan Thibodeaux • ALL OF ISIS!