GROUND UTILITY NETWORK DECIPHERING AUTOMATED MACHINE GROUP 10 BLAKE SIMONINI DIDIER LESSAGE GABRIEL RODRIGUEZ G.U.N.D.A.M.

What is it? A robot whose primary function is solving mazes of varying types using the wall follower method of maze solving Maze will be custom built with a layout capable of being changed to any type depending on the user’s specifications

Motivation Provide a system for exploring locations others cannot. One of the main advantages of using a robot to traverse unexplored territory becomes evident in places where humans can’t go due to size or potential hazards, such a cave.

Parts Being Used Two ultrasonic sensors for the sides One ultrasonic sensors for the front One MSP430 microcontrollers RC Car Base Two XBee Modules

DIDIER LESSAGE Failed Design

GUNDAM 1.0 Chipped gears  Solutions?  Attach plastic base to front for reduced friction after lost front wheels  Attach a ball to base to allow for smoother movement  Turns now made virtually impossible on carpeted surface Blown out motors  Solutions?  New motors, resulting in changed values for the software Low weight support  Solutions?  New Chassis

GUNDAM 2.0 Four ultrasonic sensors Two on sides to detect angles  Auto correction RC Car Base Two motors control front and back Issue?  Blown out sensor during construction  Turning proved difficult without isolation

BLAKE SIMONINI GUNDAM 3.0/Controller

GUNDAM 3.0 Added a connector to interface with the MSP430 development board without having to remove the Processor Cleaned up the wires and used colored wires for what each line was Clamps to keep everything organized Wires don’t interfere with sensors now

Motor Microcontroller Deals with collision detection Calibration of the motors Directly controls whether the robot is turning left, turning right, or going forward Interfaces with the Ultrasonic sensors in order to solve a particular kind of maze (which will be explained later)

Motor Microcontroller H-Bridge

Motor Microcontroller Input 1Input 2Front Motor Output (Steers left and right) Low Steer Straight HighLowTurn Wheels Left LowHighTurn Wheels Right High Steer Straight – Motor Off Input 1Input 2Back Motor Output (Drives forward and backward) Low Nothing Happens High Nothing Happens LowHighDrive forward HighLowDrive backward

Motor Microcontroller

Battery Options AA Batteries  Wouldn’t supply enough current and when they got hot they would supply less current D Batteries  Supplied enough current, but are too heavy. Lithium Polymer  Supplies enough current and is lightweight

Wireless Subsystem - ROBOT MODULE - Mounted on the robot to send and receive information from the MSP430 - COMPUTER MODULE - Connected through a computer’s USB port to send and receive data from the Java GUI.

Robot Module PCB layout  XBee Wireless Transceiver Module  Interface with MSP430 through UART

Computer Module PCB layout  XBee Wireless Transceiver Module  CP2101 UART to USB Interface XBee through UART to PC USB

XBee Wireless Module Encrypt data in AES-128 algorithm Specifications:  3.3V operating voltage  2.4GHz operating frequency  Adjustable Power output mW  Range 120m  Data rate: 250kbps  UART interface

UART to USB Bridge (CP2102) USB Bus powered powered: V Baud rate up to 921.6kbps On chip voltage regulator Virtual COM port for GUI

Range Finder Subsystem -INFRARED SENSORS The initial plan was to mount one on the left side and another on the right side of the robot. -ULTRASONIC SENSORS The initial plan was to mount one sensor on the front and another on the back of the robot.

Infrared Range Finder (GP2D120) Operating Voltage 4.5V to 5.5V Operating Current 33 to 50mA Measures 4cm to 30cm Analog output

Output Voltage (V) vs. Reflected distance (cm)

IR Sensor Malfunction During the construction of GUNDAM 2.o, an IR sensor was damaged Solution?  Two ultrasonic sensors were then used to replace the IR sensors that were originally planned to be used to auto correct and detect paths  GUNDAM 3.0 modified this even further by only using one sensor on each side

Final Ultrasonic Layout One ultrasonic sensor mounted on the left, the other on the right  Used to auto correct the GUNDAM while traveling straight  Used to detect paths One ultrasonic sensor in front  Used to detect obstacles  Used to detect forward paths

Ultrasonic Range Finder Measures 2cm to 3m Operating Voltage 5V Current consumption 20mA Ultrasonic Frequency 40kHz Communication  Positive TTL Pulse

Physical Maze Plastic, Wood, Metal, Rubber, and Paper reflect ultrasonic waves. Things to consider:  Cost : Metal > Plastic > Wood  Ease of Manufacturing: Metal > Plastic > Wood Wooden planks, each one foot in length

Maze Layout

Maze Solving (Path Finding) Algorithms Wall Follower  Simple maze solving solution that involves following the left side of the maze, including any turns that may follow. Will be the default maze solving method  This solution is only valuable in certain maze situations. If the entrance of the maze happens to lie in the center and not on the outside edge, or if a wall happens to lie on its own with no connections, it will fail

GUNDAM Maze Solving Walkthrough GUNDAM continues forward until a path is detected on one of its sides. It will try to center itself with the walls while it is moving forward. If path detected:  Check for a left_path();  Check for a front_path();  Check for a right_path(); When each path is open, we know we have solved the maze.

How Turning is Done The Ultrasonic Sensors become inaccurate after they are angled at an object past about 45 degrees. To determine a turn, we use a wall around the robot for the turn and turn the robot until that wall distance is giving very large and inaccurate values from the sensor. This way we can get an idea of how far we have turned, even though the sensors aren’t that accurate for turning. Drawback is that we can’t have a full intersection, since not having at least one wall on a turn would break this idea. Turning has to be three point turns.

How To Perform Proper Turns

Side Feature: Maze Drawing Draws out maze as GUNDAM solves using the wall follower method Upon reaching each node, present paths are sent to laptop The same algorithmic idea on GUNDAM is applied to path to predict next stretch of maze pathways to draw out as the GUNDAM’s next move Packets may be lost or resent, causing software to not be reliable

Progress

QUESTIONS?