Unmanned Aerial Vehicle 16 Foot Wingspan Flying Wing

Unmanned Aerial Vehicle 16 Foot Wingspan Flying Wing Christopher Good Test Manager, Senior Software Engineer AAI Corporation, Unmanned Aerial Vehicles Division Graduate Student, Master of Science, Mechanical Engineering Department of Mechanical Engineering University of Nevada, Las Vegas Home email: chrisgood@comcast. net Work email: good@aaicorp. com This Master's Project is an on-board autopilot program running on a micro-controller that will control a dynamic system; an aircraft in flight. The aircraft is a 16 foot wingspan flying wing modeled on the Northrop N-9 M flying wing. Three aircraft have been built: an 11 foot testbed, a proof of concept half scale 8 foot aircraft, and the full size 16 foot wingspan aircraft with the computer on-board. The onboard computer has an autopilot program. Initially, telemetry will be downlinked within a video signal as textual overlays on the picture. Further development with other controllers will allow waypoint navigation based on GPS input.

Flying Wing UAV Control Surfaces Elevons Drag rudders (each wingtip) Power Twin Ducted Fans OS. 65 VR-DF engine Turbax III fan unit Flight Control Net. Media Basic. X-24 micro-controller Sensors Analog Devices ADXL-202 accelerometer Nanotron NA 070 tilt sensors Motorola pressure transducers Hall-effect sensors & PIC event counters Upgraded Flight Control New. Micros ISOPOD

Prototype & Construction Half size prototype This plane was built and test flown to prove the airfoil and airframe were stable. An OS 46 engine and tractor propeller provide power. No drag rudders are on this airframe and it is controlled only by remote control. Full size construction Wing tips (6’ each) plug in to the center section, which holds computers, sensors, engines, fuel, RC gear, batteries.

Avionics The attitude sensors were supplied for free as test units; Analog Devices supplied the ADXL-202 accelerometers and Nanotron supplied the NA-070 tilt sensors. Leads to computer serial RS-232 connector NA-070 tilt sensors Net. Media Basic. X-24 ($40) Motorola MPX-4115 A pressure sensor for altitude ($20) 0 -65 k feet ADXL-202 accelerometer Motorola MPX 2010 G low pressure sensors for airspeed ($10 for three) 0 -1. 3 psi, 0 -705 mph Infra-red remote receiver for short range (<5 ft) control ($5) 9 volt power

Ground Control Station JR Radio Collinear Antenna WIT 2410 RF SERIAL (2) Trainer Signal 2. 4 GHz Down-converter Noteworthy PCMCIA Video Capture Compaq Laptop USB Gameport to USB Converter Gameport RC to PC Gameport Converter Autopilot and Navigation Flight with RC Backup Ground control of the ISOPOD will be done via a WIT 2410 RF modem transceiver identical to the airborne unit. The video signal will be down-converted to a base-band composite signal and captured for display on the laptop by the PCMCIA video capture card. This eliminates the need for a separate TV to view airborne video. Manual control of the aircraft will be done with a JR radio. The analog stick movements are converted to the standard JR digital trainer box signal. This digital signal is converted to the standard PC analog gameport signals, and finally converted to a USB signal for input to the laptop. RF Modem Datalink The datalink will done with Cirronet WIT 2410 2. 4 GHz spread spectrum wireless industrial transceivers. These plug into the serial ports of the computers at each end of the link and are invisible to the serial connection. They transmit at 100 m. W and frequency hop to any one of 64 preprogrammed patterns.

Basic. X-24 Sensors Analog ADXL 202 Remote Control Receiver Video Transmitter SERIAL (1) Data Acquisition, Display Nanotron NA 070 Tilt Sensor Camera Roll Nanotron NA 070 Tilt Sensor DIGITAL (1) BOB-II Video Overlay Pitch rate Pitch DIGITAL (1) Antenna u. Blox GPS Roll rate Piezo gyro DIGITAL (2) Dipole Antenna Pitch Piezo gyro DIGITAL (2) Roll SERIAL (1) ANALOG (1) (x 16) Data Gathering Flight with RC Control Only Initial testing will include data acquisition only; data will be displayed to the controlling PC on the ground and via the BOB-II video overlay module in the air. GPS data is displayed only. Analog input is converted with an 8 channel, 10 bit ADC. MPX 2010 G Pressure Sensor MPX 4115 A Pressure Sensor Airspeed Altitude

Basic. X-24 Remote Control Receiver Sensors Safety MUX Video Transmitter SERIAL (1) Data Acquisition, Display, Autopilot Nanotron NA 070 Tilt Sensor Camera Roll Nanotron NA 070 Tilt Sensor DIGITAL (1) BOB-II Video Overlay Pitch rate Pitch DIGITAL (1) Antenna u. Blox GPS Roll rate Piezo gyro DIGITAL (2) Pitch Piezo gyro DIGITAL (2) Roll Analog ADXL 202 Serial Servo Controller (SSC) SERIAL (1) Dipole Antenna Analog ADXL 202 SERIAL (1) ANALOG (1) (x 16) Autopilot Flight with RC Backup After data acquisition flights, autopilot control will be added. This is inner loop control: straight and level flight at a preset airspeed. GPS data is displayed only. The SSC, safety MUX, and autopilot inner loop software added here. MPX 2010 G Pressure Sensor MPX 4115 A Pressure Sensor Airspeed Altitude

ISOPOD Sensors Analog ADXL 202 Safety MUX Pitch DIGITAL (2) Piezo gyro Roll rate DIGITAL (2) Remote Control Receiver Roll Piezo gyro Pitch rate MPX 2010 G Pressure Sensor Alpha MPX 2010 G Pressure Sensor Beta DIGITAL (1) Dipole Antenna Video Transmitter BOB-II Video Overlay Antenna u. Blox GPS SERIAL (1) Data Acquisition, Display, Autopilot, Navigation DIGITAL (1) ANALOG (1) SERIAL (1) MPX 2010 G Pressure Sensor ANALOG (1) SERIAL(2) Camera WIT 2410 RF Dipole Antenna DIGITAL (1) Autopilot and Navigation Flight with RC Backup The ISOPOD has much greater capabilities than the Basic. X-24. It has dedicated PWM servo outputs and I/O counters, and will be able to handle all navigation tasks by itself. Analog input is converted with an 8 channel, 12 bit ADC. (x 16) Airspeed MPX 4115 A Pressure Sensor Altitude Hall Effect Sensor Tachometer L/R

Sensors Accelerometers: Analog Devices ADXL 202, 2 axix, 2 -g accelerometers. Rate Gyros: Murata Piezo rate gyroscope. I bought a non-working Gyropoint mouse on e. Bay, cheap. By gutting the mouse and removing the piezo gyro daughterboard, I have two rate gyros already soldered onto a board and ready to use. Tilt Sensors: Nanotron NA-070 electrolytic tilt sensors, 0 – 70 degree range. Altitude: Motorola MPX 4115 A, ~1 – 15 psi, 0 -65 k feet Vout to measure 0 -4000 feet (x 16) 10 bit ADC -> 4 ft resolution 12 bit ADC -> 1 ft resolution Non-inverting Amplifier Gain = 16 = 1+(RB/RA) = 1 + (1. 5 M/100 K) = (x 16)

Airspeed Sensors & Pitot Tube Mathematics Airspeed: Motorola MPX 2010 G, 0 -1. 3 psi, 0 -705 mph 10 bit ADC -> 705/1024 =. 68 mph 12 bit ADC -> 705/4096 =. 17 mph I needed to determine what the maximum pressure the pressure transducer would experience in flight, so I could buy the right sensor for airspeed sensing. The pressure in the ram section of a pitot tube is comprised of two components, the dynamic and the static. Because most pressure transducers sense the difference between some input and static (gauge pressure), we only need to look at the dynamic pressure exerted by the moving air. Dynamic fluid pressure is defined as: P(dynamic) = 0. 5 (r) (v 2) , where v = velocity of fluid (air), r = density of fluid (air) r(air) @ sea level, incompressible (low Mach number) = 1. 229 kg/(m 3) We will assume a max velocity of 50 m/s (111 mph). So we get: Pmax=. 5 (1. 229 kg/(m 3)) (50 m/s)2 = 1536. 25 kg/(m s 2) We need to convert this to PSI. To do that, we need to convert kg to pounds(force), which is different from pounds(mass). Remember the Mars Observer satellite? It went splat because NASA forgot to convert pounds(force) to pounds(mass). 1 pound(mass) =. 4535 kg 1 ft =. 3048 meter 1 pound(force) = 32. 174 pound(mass) ft/sec 2 (multiplied by gravity at sea level) 1 ft 2 = 144 in 2 After all these numbers are put in the equation, we get: P(dynamic, air) = 32 pound(force) / ft 2 @ 111 mph =. 22 pound(force) / in 2 @ 111 mph =. 22 psi @ 111 mph So, to measure airspeed up to 111 mph, we need a pressure transducer that can read at least. 22 psi. I have three Motorola MPX 2010 G pressure transducers that are rated at 1. 4 psi. They should work up to 318 m/s or 705 mph (in an incompressible flow, which at 705 mph is not true, but anyway. . . ) No problem.

Video Downlink A Pixera mini camera ($26) will take video. It feeds into a Decade Engineering BOB-II video overlay module ($85) that accepts commands via a serial line. The output of that feeds into a Comtech 100 m. W 2. 4 Ghz PLL controlled RF module ($45). The RF module is controlled by a PIC ($12) that selects the frequency based on dip-switch settings. The RF module feeds directly into a dipole antenna, built from plans found on the internet. A commercial X-10 2. 4 GHz receiver ($25) will be used to down-convert the video signal for display on a standard television. I will use a omnidirectional collinear vertical stacked dipole antenna built from plans found on the internet.

BOB-II Video Overlay Bob-II overlays 28 columns x 11 rows of white text with a black border. Everything underlined is updated; all else is static. Air sensor data and attitude data are updated as fast as the micro-controller can process the sensor inputs. GPS data and tachometers are updated at 1 Hz. L XXXXX RPM = left tach (rpm) L 9 9 9 r p m A 9 9 9 mp h P 7 0 U R 7 0 R 9 9 9 f t A XXX mph = air data airspeed (mph) XXXXX ft = air data altitude (ft) R 9 9 9 r pm P 9 0 U R 9 0 R R XXXXX RPM = right tach (rpm) (Nanotron tilt sensors) P XX U/D = pitch in deg, up/down (Analog accelerometers) P XX U/D = pitch in deg, up/down R XX R/L = roll in deg, right/left h h : mm : s s G 9 9 9 mp h d d : mm : s s. N HD 3 6 0 d e g 9 9 9 f t d d d : mm : s s E hh: mm: ss = GPS Time G XXX mph = GPS ground speed (mph) dd: mm: ss N/S = GPS latitude HD XXX deg = GPS heading (deg) XXXXX ft = GPS altitude (ft) ddd: mm: ss E/W = GPS longitude

Servo Control Serial Servo Controller (SSC) A Scott Edwards Electronics SSC ($29) accepts commands via a serial line and can control up to 8 servos.

GPS Trimble-Lassen SK 8 Trimble-Lassen LP u. Blox PS 1 GPS Receivers The Trimble SK 8 (5. 0 volts power, $35) and LP (3. 3 volts power, $25) each monitor 8 satellites. The LP is a low power version of the SK 8, and both receivers output NMEA or TSIP messages on serial port 1. The u. Blox ($80) monitors 12 channels, and outputs NMEA or SIRF messages on serial port 1. All receivers accept RTCM-SC 104 differential GPS corrections on serial port 2. GPS Antennas I decided to make my own active antenna using commercial components. The TOKO DAX 1575 MS 63 T ceramic patch element (18 mm x 18 mm) is $5 from AVNET. All of these receivers require an active antenna, which means this needs some type of low noise amplifier (LNA). After searching many homemade GPS antenna web pages, I found the M/A-COM AM 50 -00002 for $4 from MHz Marketing. M/A-COM AM 50 -00002 1. 575 Ghz LNA TOKO DAX 1575 MS 63 T GPS CERAMIC PATCH ELEMENT

Controller Prototypes Ampro 286 miniboard. This single board computer ($40) with a 286 10 MHz processor was the first board I picked to be the autopilot onboard computer. It has a small ISA backplane that can be attached for ground testing. More research has lead to the use of the smaller, lighter Flashlite V 25+ single board computer. Flashlite V 25+. This single board computer ($40) with a 10 MHz processor was the next board I picked to be the autopilot on-board computer. It runs a straight DOS 3. 3 environment, has a 128 KB flash hard drive, and lots of I/O. Continuous advances in hardware have left this board behind also, allowing the much smaller Basic. X-24 and ISOPOD to be used. Additional Development Antenna Trimble LP Antenna Trimble SK 8 MUX Multiple GPS Receivers Further development may include multiple GPS receivers. All the Trimble units will be MUXed to a single serial port and replace the u. Blox GPS.

Test Hardware The following pages show some miscellaneous hardware, and some equipment that I built for testing and other hardware configurations. For example, the ADC’s were going to be used for analog input before I decided on using the Basic. X-24, which has its own 10 bit, 8 channel ADC. Analog Devices ADXL 105’s. Each one measures 1 to 5 g’s in one axis. The small board on top is an op-amp acting as a data buffer. Analog-to-digital converter AD 7812. 10 bit, 8 channels. I made this board with capacitors to smooth out the supply voltage (also the reference voltage), and a 7805 voltage regulator as the power supply. Analog-to-digital converter ADC 0838. 8 bit, 8 channels. I added two micro potentiometers to channels 1 and 2 for testing. This board also has a 7805 voltage regulator as the power supply.

Test Hardware Rate Gyroscope. A Futaba G 153 BB rate gyro will be used to smooth out yaw oscillations via the drag rudders. I have an identical gyro in my RC helicopter and it works very nicely. Mercury Tilt Switches. Initial testing was done with a set of mercury tilt switches for absolute left/right roll, up/down pitch. It was built as a temporary input device for attitude input. This will not be used in the aircraft. They were acquired from a air-conditioning company (from old thermostats) for free. Printer Port Indicator. To verify the printer port interactions, I built this indicator device to show when the individual bits in the parallel port I/O area are on and off. The 5 push-button switches are used to manually simulate the data coming from an input device (A/D converter, for example). This was built from parts from Radio Shack and has been used for testing digital I/O with a PC’s parallel port.