2009 Student UAS Competition. Abstract:

Transcription

1 UNIVERSITY OF PUERTO RICO MAYAGUEZ CAMPUS COLLEGE OF ENGINEERING 2009 Student UAS Competition Journal Paper Team Members: Pablo R. Mejías, Merqui Galarza Jeancarlo Colón Naldie Torres Josue Comulada Veronica González Faculty Advisor: Dr. David B. Dooner Professor of Mechanical Engineering UPR Mayaguez

2 Abstract: The following paper presents the design developed by the University of Puerto Rico, Mayagüez Campus that has meet with the mission presented by the Association for Unmanned Vehicle Systems International s (AUVSI) rules and will compete in the 2009 AUVSI s Student UAS Competition. The purpose of the aircraft is to be able to navigate through a predetermined course autonomously, meaning with a pilot physically at the controls. Furthermore, the aircraft will fly pass so-called Global Positioning System (GPS) waypoints in order to arrive to a search zone. In such area, by utilizing an onboard imagery system, the aircraft purpose is to find and determine the identity of the targets. The system found on the UPRM-AlphaHawk UAV autonomous aircraft were designed and fabricated with household materials and store bought components. The design, research, and fabrication of the aircraft are divided into four main areas and their corresponding sub-area: aircraft assembly, autopilot, imagery, and the ground control station. Safety systems, such as fail-safe, were design and placed on the aircraft in order to reduce risk factor during the flight of the aircraft. 1. Introduction: In the last century the aerospace industry has seen a great technological boom. From the Wright Brother s first flight all the way to the Space Shuttle, new breakthroughs have constantly paved the way for new technologies to emerge. The Unmanned Aerial Vehicle (UAV) is part of the new era of technological marvels. Since 1902 aircraft have gotten bigger, faster and more dependable. With advancement in technology and efficiency came a greater demand for aircraft usage. Aircraft use has become so widespread that they are now a vital part in our global economy. Recent achievements have allowed aircraft to perform simple tasks without requiring direct human interaction. These advancements allow the use automated airplanes to perform simple or dangerous tasks with a lower cost and without endangering human lives. The term Unmanned Aerial Vehicle stands for any air vehicle capable of sustaining flight without an onboard crew; it could fly autonomously or piloted remotely. Unmanned vehicles have long existed, simple radio controlled airplanes are nothing new. Autonomous vehicles offer a degree of independent flight, able to guide themselves to given waypoints and perform specific tasks without any or little human interaction. Radio control does not offer this independence. The uses for this booming technology are mainly military reconnaissance, civilian surveillance and mobile signal transmission. Recently the uses extend to Page 2 of 16

3 law enforcement agencies and the planetary exploration of Mars. These aircraft come in all shapes and sizes, from simple hand size micro planes with small video cameras attached, to full size autonomous planes able to fly for long periods of time. The various sizes enable these aircraft to adapt to different roles and capabilities. The future for this technology certainly looks bright. These vehicles can one day be used for more than military tasks. They can be used to gather meteorological information like hurricane hunters. They could be used for search and rescue operations and, since these aircraft don t require human control, they could stay on station searching for a much longer period than regular aircraft. They could also be used to quickly and inexpensively transport goods like medical supplies. 2. Mission Objectives: 2.1 Parameter Autonomous Flight Threshold: During way point navigation and area search Objective: Complete flight, including takeoff and landing Imagery Threshold: Identify any two target characteristics: Shape Background color Alphanumeric Alphanumeric color Target Orientation Objective: Identify all five target characteristics Target Location Threshold: Determine target location using ddd.mm.ssss format within 250 feet Objective: Determine target location within 50 feet Mission time Threshold: Less than 40 minutes total Imagery/location/identification provided at mission conclusion Objective: 20 minutes Imagery/location/ identification provided in real time Page 3 of 16

4 In-flight re-taking Threshold: Add a fly to way point Objetives: Adjust searching area 3. AlphaHawk UAV In the 2007 competition, we experimented an overload aircraft. For this year, we were very meticulously distributing payload inside the aircraft. An excellent airframe to lift weight is the flat-bottomed aircraft. Our research of aircraft models ended when we chose the ARF 110 Sig Rascal but this model was very hard to find (Before we purchase it, a company told us that it was in stock and then they sold the last one). Then we had to select the Senior Telemaster because it is one of the best ARF s in its category. The Senior Telemaster has 94 of wingspan and provides massive lifting ability. Lift force is one of the most important factors of this project to achieve an excellent mission performance. Also, we had to change the color of the Senior Telemaster to our Institution official colors (White and Green). 3.1 Aircraft Specifications: Table 3-1: Airframe Specs Figure 3-2: Senior Telemaster (Representative picture) Make Model Aircraft Type Wingspan Length Wing Area Flying Weight Hobby-Lobby Co. Senior Telemaster Tail-dragger 94 in. 64 in sq. in lbs (empty) Page 4 of 16

5 Table 3-3: Engine Specs Make O.S. Engines Model FS-70SII Engine Type Single Cyl. 4-stroke Bore 25.8mm (1.02 ) Stroke 22.0mm (.866 ) Rated Power 11,000 rpm Engine Weight 22.1 lbs. Figure 3-4: O.S. FS-70II Engine Figure 3-5: Telemaster Plans (Three-View Plan) Page 5 of 16

6 4. Target Identification & Imagery 4.1 Imagery System 2009 Student UAS Competition AlphaHawk s rotating mechanism is located in the mid-lowest point of the aircraft near to the CG to capture quality images. Alpha s rotating mechanism was re-designed and substituted by an all- aluminum pan/tilt mount with interval movement to improve better field of view from its location. Sony CyberShot Digital Camera (Representative picture) Camera Hardware A powerful 1.5 mile camera transmitter provides clear images from any altitude. All the specs of the camera help to acquire great images from the targets and objects. This is a universal transmitter and any camera is compatible with this device including our 8.1 Mega-Pixel cybershot. Figure 4-1: 1.5 Mile Transmitter Figure 4-2: 2.4 GHz Receiver Page 6 of 16

7 4.2 Rotating System & Imagery: Page 7 of 16

8 5. Safety Features and Avionics: 5.1 Safety Always safety will be first. AlphaHawk is equipped with safety devices as a safe circuit that controls all the servos if the signal is lost or low voltage, a glitch buster and a RC integrated throttle-cut switch. Figure 5-1: Servo Fail Safe circuit board Figure 5-2: Throttle cut switch Glitch Buster (Jomar Electronics) The glitch buster reduces radio interference caused by long leads and heavy noise. This device is very useful with the micropilot 2028g to avoid servo malfunction. Page 8 of 16

9 Figure 5-3: Glitch Buster circuit 5.2 Avionics: Micropilot: The heart of the UAV Figure 5-4: The anatomy of the MP 2028g Flight Computer (Micropilot Manual) Micropilot Capabilities: 1 Hz GPS update rate Move servo at waypoint Change altitude at waypoint Change airspeed at waypoint User definable holding patterns User definable error handlers RPV and UAV modes Supports DGPS accuracy 1000 waypoint command buffer In-Flight communications Futaba Radio Control Communications consists of a Futaba 72 MHz PCM 7-channel Radio Control. AlphaHawk operates in two bands: 43 & 48 on 72 MHz. The Radio is multi-purposes, in case of failure we can use the transmitter and return it into PIC mode. Figure 5-5: Futaba PCM-7CHP Transmitter Page 9 of 16

10 Radio Modem Communications are provided by the 910 MHz Radio Modem (base). This device was included in the MicroPilot Package. We can transmit all the images, flight information, and you can see all the activities on the MicroPilot Horizon Software including tracking and GPS coordinates. This is very essential and the most important device to complete the competition and all the communication and the status of the aircraft in the air is received with this device. Figure 5-6: 910 MHz RadioModem Base This modem serves as a downlink from the MicroPilot to access the sensor data and monitor the state of the UAV. MicroPilot Horizon Software To communicate with the Alpha UAV, we use the Horizon software, which is included in the MP2028g Autopilot package. Through Horizon, we can load and create flight programs and configure our sensors and servos to observe and interact with the UAV in flight. Horizon tracks the progress of the UAV in real time allowing the team of access critical mission data such as altitude, attitude, air speed, position and autonomous take-off and landing provided by de AGL ultrasonic sensor. Figure 5-7: MP Horizon Software screenshot Page 10 of 16

11 Figure 5-8: PID loop window & flight instruments Figure 5-9: The AGL Ultrasonic sensor provides takeoff/ landing feature Page 11 of 16

12 6. System diagrams & layouts 6.1 UAV/ GCS Communications 2009 Student UAS Competition Figure 6-1: System Communications Diagram Page 12 of 16

13 Figure 6-2: Micropilot Flight computer layout 6.0V Ni-Mh Battery Pack GPS ANT. Comm. Port 4.8V Ni-Mh Battery Pack 1 MP 2028g AutoPilot Flight Computer Servo Board Battery Back-up System 4.8V Ni-Mh Fail Safe Circuit L/Aile. R/Aile. Elev. Thro. Rudd. Battery Pack 2 Glitch Boster Rx Ant. 72MHz PCM Receiver GPS Batt. Ultrasonic Sensor RM Ant. 910MHz MicroHard AGL Module RadioModem Pilot Static Port Pressure Port Page 13 of 16

14 7. Preflight Checklist Pre-flight Checklist While in lab: Hardware tests: Commbox: Sufficient Power (gel cell if needed) Antenna attached USB-Serial Adapter Programmed with compatible code Laptop: Compatible software installed Sufficient battery life (inverter if needed) Check USB-Serial adapter port mappings and compare with VC settings On the plane: Autopilot battery voltage > 6.0 V Modem: Antenna connected, getting COMM Good connection between modem and autopilot (cable) GPS Good connection to autopilot (cable) Good satellite lock Flight capability check Tuned PID loops Trim settings Autopilot should be temp camped previously Completely charge our transmitter and receiver batteries before your first day of flying. Check every bolt and joint in the Alpha UAV ensure that everything is tight and well bonded. Double check the balance of the airplane. Do this the fuel tank empty. Page 14 of 16

15 Check the control surfaces. All should move in the correct direction and not bind in any way. If your radio transmitter is equipped with dual rate switches double check that they are on the low rate setting for your first few flights. Check to ensure the controls surfaces are moving the proper amount for both low and high rate settings. Check the receiver antenna. It should be fully extended and not coiled up inside the fuselage. Properly balance the propeller. An out of balance propeller will cause excessive vibration which could lead to engine and/or airframe failure. 8. Apendix A1. Term Nomenclature AGL AMA ARF CAD CG CIC FM GCS GPS Li-Ion MP MSL Ni-Cd Ni-Mh Above Ground Level American Model Academy Almost Ready-to-Fly aircraft Computer Aided Design Center of Gravity Computer in Command Frequency Modulation Ground Control Station Global Positioning System Lithium Ion Battery MicroPilot Autopilot System Mean Sea Level Nickel Cadmium Battery Nickel Metal Hydride Battery Page 15 of 16

16 PIC RM Rx Tx UAV UPRM USB Pilot in Command Radio Modem Receiver Transmitter Unmanned Aerial Vehicle University of Puerto Rico at Mayagüez Universal Serial Bus A2. Sponsors and Acknowledgements Page 16 of 16