Real-time Intelligent Mine/Metal Detector Mobile Robot
Department of Electrical and Computer Engineering
Azad University of Arak
ABSTRACT:
Undiscovered military mines buried all around the world are serious threats to the human life. Designing an autonomous mine detector robot with an intelligent path finding and tracking algorithm could help the military and human rights
organizations to discover and dispose the mines without direct human contact.  
The first ROBODEMINER competition in Amir Kabir University [Iran, Tehran] August 19-21, 2002 was an excellent opportunity for enthusiastic robotic teams to design and implement an autonomous robot basd on real-time operation on a real terrestrial path.

System Description:
The robot is equipped with two transceiver solenoid coils very close to the ground with 35cm depth accuracy. A real-time image processing algorithm enhanced with tracking and path finding features, controls the robot with real-time images acquired from a camera roughly installed 5m above the competition path. In case of mine detection a set of high-light LEDs on the top of the robot operate as a discovery signal for the image processing algorithm, hence the coordination of the robot obtained and a flag is set in the trajectory matrix of the robot movement path.
 
 
Professor Kenzo Nonami
Team Members:
1- Nima Ziraknejad
2- Ali Nazem
3- Behzad Bahr Hosseini
4- Ali Mohammad Shams-Ahmadi
5- Roozbeh Charkh-Tabian
6- Abolfazl Shakibaie
7- Mohammad Mohammadi
Wireless Communication and power supply: The wireless (RF) communication between the robot and the computer system and the Ni-Ca chargeable battery as the power source, enhance the robot to operate with no need for any signal and power cable.
The computer sends the control signals to the UHF receiver circuit on the robot, the robot and the real-time computer running the image processing software can communicate with each other in an assumed circle with 150m diameter.
Microprocessor system :
The powerful 68HC11-12 microprocessor board with internal memory (EPROM, EEPROM, and RAM) is the heart of the control system on the robot. The computer board is programmable via RS232 serial communication for the first time and forever. The various algorithms to drive the stepper motors for different movements and rotation power, the error detection/correction algorithm to correct the robot movements and rotations plus the communication program between the receiver and the microprocessor are real-time programs run on the computer board.
 
Metal Detector circuit
Each solenoid coil sensor is based on two individual coils, operate as a transmitter and receiver. An audio oscillator drives the primary winding (with 20 KHz square wave) to perform like a transmitter. the inducted magnetic field received with the secondary winding will be a square wave with 180 degree phase differnce. A mine or a piece of metal can produce more phase difference on the inducted magnetic field and from this instability and deviation the metal or the mine is noticeable.

Image processing and motion control Software 

A Visual C++ based program handles two important tasks:

1.Image processing with respect to the indicators installed on the robot,

2.Motion control and trajectory planning.

The image acquisition board receives the data from an installed PAL camera with 4 meters height above the ground. The color detection strategy is used to capture the orientation of the robot and rendering the exact coordination of the robot on the screen.

 

Based on the robot orientation saved in the motion control matrix, the program decides to send the appropriate control data to move the robot in a certain direction. A powerful RF transmitter sends the received control data from the program via LPT port of the PC to the mounted receiver on the robot. In case of finding any mines buried under the ground the mine detection indicator (a red high bright LED) triggers the software to save the coordination of the mine.

The software is quite robust to the intensity of the MAT environment and the colors and features advanced settings for robot speed, port selection and capturing rate parameters. A snapshot of the software is displayed in the picture.