Autonomous Turret (Auto-Turret) for Student Design Competition 2013

[aggiecec2013]

Contact Information

University: Texas A&M University

Team Members (w/ year of graduation): Dallas Smith (2013), Robert Rice (2013), Carlos Rivero (2013), and Juan Ruiz (2013)

Faculty Advisors: Sam Villareal

Email Address: lowwjack2000@gmail.com

Project Information

Title: Autonomous Turret (Auto-Turret), United States

Description:

The Auto-Turret is a weapon system designed for military applications in remote regions. This concept uses its integrated components to protect a designated area within its radius by detecting, tracking, and eliminating enemy targets, while leaving friendly personnel unharmed. Other, non-lethal, variations are possible.

Products:

NI LabVIEW Student Edition 2012, sbRIO 9631, Laptop PC, AXIS M1011 Network Camera, SPG785A-BM Servo-motor, PIR Sensors, Router

The Challenge:

The objective of our project was to design a cost effective system capable of protecting a specified area near a remote military installation or camp using either lethal or non-lethal methods. Implementation of such a system could then be used to remove military security forces from any immediate danger and/or improve base assault reaction time, thus reducing troop casualties.

The Solution:

The solution was to build an Auto-Turret weapon system capable of detecting targets, deciding whether the target is friend or foe, and eliminating the foe. Since this was a student environment (and for many safety issues) we chose to use an Airsoft rifle for our simulated weapon fire. The implementation of this type of system required the development of six different subsystems: Power Management and Control, Main Control, Turret Alignment and Control, Identification Friend or Foe, Image Recognition and Tracking, and Weapon Firing. Each subsystem is described in detail below. The basic flow of stages begins with target sensing using PIR sensors in an array surrounding the Auto-Turret system. If a suspect trips one of these sensors without having the "friend" identification circuit on person, the weapon rotates, with the camera attached, to the sector in which motion was detected. At this point the camera takes control and tracks the moving target in its field of view. After a specified time interval the weapon system engages the enemy target (if no "friend" identification circuit is present). When the target is eliminated the weapon rotates back to center and the system "resets" awaiting further motion in its range.

Six Subsystems

     i.           Power Management and Control

The Power Management and Control subsystem allows the Auto Turret system to be a stand-alone system that requires no external connections. The subsystem uses two 12V 7.5 A-Hr rechargeable batteries to power the entire system. These batteries feed power to two separate PCBs, the first of which boosts the voltage to the required 24V for the sbRIO 9631 for the Main Control subsystem. The second PCB contains circuitry for each subsystem’s hardware components, along with enables from the Main Control subsystem to control the activation of these hardware components to save power. The last component of the Power Management and Control subsystem is the switch mechanism that allows for a selection between an external power supply or battery power. The switch mechanism allows for testing and debugging of the entire system without damaging or draining the batteries.

ii.       Main Control

The Main Control subsystem is the “Brain” of the entire Auto-Turret system. It accepts analog and digital inputs, processes this information, and produces the necessary output enables and signals required for full system functionality. To perform these actions a National Instruments (NI) sbRIO 9631 board was used, along with its capability of Host-FPGA functionality. It also introduces the need for LabVIEW programming to interact with the board’s capabilities.

iii.      Turret Alignment and Control

The turret’s detecting angle is currently over 180°. Since the camera can only view and track a limited view, the turret is automatically aligned to one of five sectors (45°), set up in a circular array. Five PIR sensors detect their respective sectors; low pass filtering and amplification circuits are mounted to the array, which is mounted using the motor center. The sensors put out a small analog signal that is filtered and amplified, before being introduced into the Main control to being compared to the selected threshold. If the threshold is exceeded, an occurrence is triggered at that sensor and that integer angle is passed to the Motor Control Memory Block, which feeds directly into the Motor VI. This VI turns angle integers into a PWM pertaining to an angle for the servo motor, using a custom made formula. After the initial angle is received from the sensor array the main control gives control to the camera; the camera and tracking algorithm then subtract or add to the motor angle during tracking of an individual. The servo motor is capable of achieving a range of 420°, but is limited to 180° for this project.

iv.     Identification Friend or Foe (IFF)

The IFF subsystem used in the Auto-Turret is based on a currently used military system, using non-secure Bluetooth communications rather than cryptography and the interrogator/transponder sequence. Our system uses an onboard and remote unit containing a Bluetooth transceiver, a microcontroller, and several other ancillary components increasing its capability for upgrades in the future to more secure communications. The onboard unit is part of the system housing and, when powered, awaits the connection of the remote unit (worn by the friendly target). Each unit contains indicators for connection, as well as a low battery indicator for the remote system.

v.      Image Recognition and Tracking

The Image Recognition and Tracking subsystem was responsible for recognizing the target in the field of view of the camera. This subsystem had its own module to perform image processing within LabVIEW called Vision Development Module (VDM). (See attached PowerPoint slides for more in depth information.)

vi.     Weapon Firing Subsystem

The Weapon Firing subsystem allows for controlled firing of the weapon system when the Image Recognition and Main Control subsystems determine the target in the Auto Turret range is a foe and needs to be engaged. The Weapon Firing subsystem takes an enable signal from the main control to activate the circuit. The firing system is much like the Power Management system but the enable is a digital high instead of a low for the Power Management. This allows safe functioning if the Main Control subsystem were to lose power. The Firing circuit PCB was designed such that it would fit seamlessly inside the grip of the Airsoft rifle used as the weapon. This allows for easy removal of the weapon for testing or to change the application of the Auto Turret System.