Lockheed Martin Challenge Avionics Final...

LOCKHEED MARTIN UAV CHALLENGELOCKHEED MARTIN CHALLENGE AVIONICS FINAL REPORT

CLIENTLO C K H E E D M A R T I N C O R P O R A T I O N

FACULTY ADVISORDR . ST E P H E N HO L L A N D

DE P A R T M E N T O F A E R O S P A C E E N G I N E E R I N G

IO W A S T A T E U N I V E R S I T Y

TEAM MEMBERSAD A M J A C O B S – T E A M L E A D E R

E L E C T R I C A L E N G I N E E R I N GM I K E P L U M M E R

CO M P U T E R E N G I N E E R I N G

R O B E R T G A U LE L E C T R I C A L E N G I N E E R I N G

RO N A L D T E OCO M P U T E R E N G I N E E R I N G

DA N I E L S T O N EE L E C T R I C A L E N G I N E E R I N G

Submitted:

May 1, 2009

DISCLAIMER

This document was developed as part of the requirements of an electrical and computer engineering course at Iowa State University, Ames, Iowa. The document does not constitute a professional engineering design or a professional land surveying document. Although the information is intended to be accurate, the associated students, faculty, and Iowa State University make no claims, promises, or guarantees about the accuracy, completeness, quality, or adequacy of the information. Document users shall ensure that any such use does not violate any laws with regard to professional licensing and certification requirements. Such use includes any work resulting from this student-prepared document that is required to be under the responsible charge of a licensed engineer or surveyor. This document is copyrighted by the students who produced the document and the associated faculty advisors. No part may be reproduced without the written permission of the senior design course coordinator.

Lockheed Martin Challenge Avionics Final Report | 2

T A B L E O F C O N T E N T S

Introduction............................................................................................................................................................................................. 5

Problem Statement.............................................................................................................................................................................. 5

Need Statement................................................................................................................................................................................... 5

Solution Summary................................................................................................................................................................................ 5

Project Plan.............................................................................................................................................................................................. 6

Concept Sketch.....................................................................................................................................................................................6

System Block Diagram..........................................................................................................................................................................7

System Description...............................................................................................................................................................................7

Operating Environment........................................................................................................................................................................8

Functional Requirements..................................................................................................................................................................... 8

Non-Functional Requirements..............................................................................................................................................................9

Market Survey...................................................................................................................................................................................... 9

Work Breakdown Structure................................................................................................................................................................10

Resource Requirements.....................................................................................................................................................................11

Deliverables........................................................................................................................................................................................12

Project Schedule.................................................................................................................................................................................12

Risks................................................................................................................................................................................................... 12

Design.....................................................................................................................................................................................................14

Design Approach................................................................................................................................................................................ 14

Specifications......................................................................................................................................................................................14

Schematics..........................................................................................................................................................................................15

Implementation......................................................................................................................................................................................15

Components.......................................................................................................................................................................................15

Layout and Integration.......................................................................................................................................................................19

Testing.................................................................................................................................................................................................... 23

Subsystem Testing..............................................................................................................................................................................23

Conclusion..............................................................................................................................................................................................26

Accomplishments...............................................................................................................................................................................26

Necessary Work..................................................................................................................................................................................26

Appendix A – Schematics........................................................................................................................................................................28

Appendix B – Team Information.............................................................................................................................................................38


L I S T O F F I G U R E S

Figure 1 - Concept sketch of assembled system.......................................................................................................................................6Figure 2 - Avionics System Block Diagram................................................................................................................................................7Figure 3 - Project Schedule Gantt Chart.................................................................................................................................................12Figure 4 - Autopilot................................................................................................................................................................................ 15Figure 5 - Onboard Radio Modem..........................................................................................................................................................16Figure 6 - Onboard Camera and Lens.....................................................................................................................................................16Figure 7 - Camera Resolution Demonstration........................................................................................................................................16Figure 8 - Onboard Video Transmitter....................................................................................................................................................17Figure 9 – Ground Station Video Receiver..............................................................................................................................................18Figure 10 – Ground Station Portable Television.....................................................................................................................................18Figure 11 - Murata DC-DC Converter......................................................................................................................................................18Figure 12 - Ground Station Laptop.........................................................................................................................................................19Figure 13 - Ground Station Radio Modem..............................................................................................................................................19Figure 14 - Assembled Autopilot Layout................................................................................................................................................20Figure 15 - Assembling Wing with Internal Antennas and Servo Wiring................................................................................................21Figure 16 - Autopilot Layout Inside Aircraft............................................................................................................................................22Figure 17 - Video System Inside Aircraft.................................................................................................................................................22Figure 18 - Bench Testing of Autopilot...................................................................................................................................................23Figure 19 - Autopilot test launch with assembled system......................................................................................................................23Figure 20 - Autopilot sensor data...........................................................................................................................................................24Figure 21 - PID Calibration......................................................................................................................................................................24Figure 22 - Radio modem testing for wireless communication..............................................................................................................25

L I S T O F T A B L E S

Table 1- Work Breakdown By Man-Hours per Team Member per Task.................................................................................................10Table 2 - Labor Cost................................................................................................................................................................................11Table 3 - Resource Cost..........................................................................................................................................................................11Table 4 - Total Avionics Cost Estimate....................................................................................................................................................12


INTRODUCTION

PROBLEM STATEMENTCurrent UAV technology is not capable of launching vertically using a rail launch system into the atmosphere. As such, current UAV’s are not suitable for use for urban operations as they must be launched away from the urban setting due to obstacles. This presents problems for certain missions that could be assisted by UAV technology.

NEED STATEMENTThe Iowa State LM Challenge Team has been asked to design an unmanned autonomous aerial vehicle to take off from a vertical or near-vertical pneumatic launch system within the confines of an urban environment. This vehicle will be used to fly low altitude reconnaissance missions and will be retrieved using a standard belly landing outside the target environment.

SOLUTION SUMMARYIn order to meet the needs of this project, the Avionics Team has decided to utilize as many Commercial Off the Shelf (COTS) components as possible to ensure compatibility and reliability as well as ease of replacement and repair in the event of damage to the aircraft. We have chosen to utilize an autopilot system with associated sensors to control and navigate the aircraft during takeoff and flight. A wireless link will be used to communicate with and control the autopilot from a ground station. In addition, a camera and separate wireless link will be used to provide a video stream to the ground station. All these onboard components will be powered by a single battery using a DC-DC Converter Power Supply Unit (PSU).


PROJECT PLAN

CONCEPT SKETCH


F IGURE 1 - CONCEPT SKETCH OF ASSEMBLED SYSTEM

SYSTEM BLOCK DIAGRAM


F IGURE 2 - AVIONICS SYSTEM BLOCK DIAGRAM

SYSTEM DESCRIPTIONCO N T R O L A N D C O M M U N I C A T I O N S

AUTOPILOT BOARD AND SENSORS

The processing board is for automated flight control. It receives input from the sensors, calculates necessary adjustments, and sends signals to the servos to make adjustments in flight. Our autopilot system is configured with ‐GPS, ultrasonic altimeter, pitot tube, barometric altimeter, IMU, and 3D magnetic compass.

ONBOARD RADIO MODEM

The on board radio modem provides communication with the ground station flight control software (via the RF ‐Receiver). It is connected to the autopilot board. It is directly interfaced with the autopilot using an RS 232 connection.‐

GROUND STATION RADIO MODEM

The ground station radio modem communicates with the on board radio modem to send and receive data between the‐ ground station and the autopilot.

GROUND STATION LAPTOP

The laptop processes the flight data received from the aircraft. It displays the flight data using the HORIZON software provided with the autopilot hardware (MicroPilot 2128).

V I D E O S U B S Y S T E M

CAMERA


The on board camera is used primarily for surveillance purposes. It streams live video back to the ground station and is ‐displayed on a portable television.

VIDEO TRANSMITTER

The purpose of the on board video transmitter is to transmit the captured video back to the ground station video ‐receiver.

VIDEO RECEIVER

The video receiver captures the incoming video signal from the onboard video transmitter and passes it along to the display for viewing.

VIDEO DISPLAY

The portable monitor displays the video feed from the aircraft; allowing the user to ascertain what lies in the area of interest.

O N B O A R D P O W E R S U B S Y S T E M

AVIONICS BATTERY

The avionics battery powers the on board avionics equipment via the DC DC Converter. This battery does not power ‐ ‐the aircraft motor or servos in order to isolate our systems from the voltage spikes induced by those high-draw devices.

DC DC CONVERTER‐

The DC DC converter is fed by the avionics battery and supplies appropriate voltages to on board avionics equipment.‐ ‐

OPERATING ENVIRONMENTThe UAV is expected to perform in an urban setting, posing unique challenges in the form of buildings and other ground-based obstacles. Our aircraft is be fitted with the highest power transmitters permitted by the FCC for civilian use to ensure that loss of Line Of Sight will not preempt use of the craft, a necessity given the numerous obstacles our aircraft will encounter. Our entire aircraft is designed to use a vertical pneumatic launch system to avoid obstacles presented by urban areas. Our choice of optics was driven by a need to protect the sensitive electronics from damage upon launch, during flight, and upon landing. Specific to the avionics system, our components were chosen to conform to the size and weight limitations inherent in aircraft systems. In addition, our components will be powered by a battery, necessitating components with low power requirements in order to lengthen endurance.

FUNCTIONAL REQUIREMENTSFR01 Be capable of autonomously navigating an aircraft using pre programmed waypoint navigation‐ ‐

FR02 Support communication with a ground station to display telemetry and position data‐

FR03 Shall provide real time video to ground station‐ ‐

FR04 Shall operate in an urban environment‐

FR05 Shall be capable of resolving a 6 inch target from an altitude of 100 feet‐

FR06 Shall be a fixed position camera‐ ‐


FR07 Shall be designed to enable a modular payload system‐

FR08 – Shall be designed to utilize a pneumatically powered vertical launch method‐

FR09 – Shall be capable of operating at least one mile from the ground station

NON-FUNCTIONAL REQUIREMENTSNFR01 Operate off of 5 or 12V to simplify power system‐

NFR02 User programmable to aid in support of vertical pneumatic launch‐ ‐

NFR03 Small size, weight, power requirements‐

NFR04 Video transmission shall not occur in the 900 MHz band to prevent interference with autopilot communication‐

NFR05 Components should utilize 5V or 12V when possible to simplify power requirements and increase modularity of design‐

MARKET SURVEYA U T O P I L O T

Many factors were taken into account when choosing an autopilot system for our project. Our team narrowed down the choices to four autopilot systems that met all the functional requirements. These four systems were the MicroPilot 2128, Procerus Kestral, Cloudcap Piccolo, and the O Navi Phoenix/AX. The MicroPilot 2128 had many good qualities. It came with great technical support, high frequency GPS update, was customizable, included easy-to-use ground station software, the ability to develop user-defined control loops, allowed for RC override, and was lightweight and small. The downside to this system was that it was expensive and had a low accelerometer saturation point at 4G’s. The Procerus Kestral had a high accelerometer saturation point of 10 G’s, it was light weight, and was small in size. Some of the downsides of this system were that it had high power consumption, poor technical support, and a low GPS frequency. The next system, the Cloudcap Piccolo, had a high GPS frequency, built-in radio modem, and a simple form factor. Some of the features that were inferior were it had a low accelerometer saturation at 2G’s, was expensive, and was large in size, heavy and had high power consumption. The final system was the O Navi Phoenix/AX. It had low power consumption, was small in size, and had a high accelerometer saturation point. The downfalls were that it had no embedded software or ground station software and had a low GPS frequency.

In the end our team felt that the best system to support our goal was the MicroPilot 2128. It had great technical support which would aid in helping the team with any technical questions we may have about the system and how it operates. Also the level of customization that this system allows for will help our team in programming the autopilot to be able to handle the unique launch. The MicroPilot 2128 also allowed for the addition of other sensors to aid in the launch and flight of the aircraft.

CA M E R A

When researching camera systems for our project our team ran into many different camera systems, many of which supplied features that were much more than what our requirements asked of our team. After much research our team narrowed the search down to cameras from two different manufacturers: Genwac/Watec and KT&C. The Genwac/Watec cameras offered adjustable frame rates and were easily configurable, but their cameras were heavy and not designed for vibrations and varying temperature and humidity. The KT&C camera exceeded the resolution requirement, was previously used in other UAVs, and had NTSC video output using coaxial connections which allows for a simpler video system.


Our team chose the KT&C camera because it was small in size, had low power consumption compared to other cameras on the market, was light in weight, and previously showed that it could be used in UAVs.

DC/DC

Our initial research into power supplies yielded three possible choices for our project. The first system was the Tri-M HESC104 which met all of our power needs but was too large to fit in our fuselage. The second system was the Tri-M IDD-936360A. This system met our power requirements and size requirements but it had no enclosure around its components which did not allow for any protection for the components. The final system that our team researched and eventually selected was a DC-DC Converter from Murata. This product met our power requirements, size requirements, and included an enclosure to protect the converter and help prevent electrical faults in the event of a crash.

O N B O A R D R A D I O M O D E M

Our team’s initial research narrowed our choices down to two different systems. The first system was the Xtend-PKG. This system met our power requirements and range requirements but the system was too large to fit in our fuselage. Even though this system was too large it was a good choice as the ground station radio modem. The system that we did choose was the 9Xtend-PKG OEM. It as well met our power and range requirements and had a small physical size which allowed it to fit well in our fuselage. In addition, this system had been used previously by other users of the MicroPilot 2128 autopilot, assuring us of compatibility and reliability when interfacing these two components.

WORK BREAKDOWN STRUCTURETABLE 1- WORK BREAKDOWN BY MAN-HOURS PER TEAM MEMBER PER TASK

Estimated Time Commitment per Task per Person

Hours Adam Jacobs

Robert Gaul

Mike Plummer

Daniel Stone

Ronald Teo

Camera/Video SystemChoose Camera System 0 0 20 20 0Choose Transmitter/Receiver System 5 0 10 5 0Test Camera/Transmitter/Receiver Systems 20 10 20 20 5Mount Camera/Transmitter Systems 20 0 5 5 20Retest In-flight 30 30 30 30 30Onboard Power System Establish Requirements 15 5 5 5 5Choose Power Supply 10 0 5 0 0Choose Battery System 10 5 10 10 0Finalize Interface With Flight Systems 20 10 15 15 5Test Onboard Power System 20 5 20 20 10Mount on Aircraft 5 5 5 5 5Test In-flight Arrangement 5 5 5 5 5Ground Station Determine Components Required from Video and Autopilot Systems 10 5 10 10 10Determine Manual Flight Override in Conjunction with Autopilot Development 20 5 15 15 5Determine Power Source Required 5 5 5 5 5


Compile Components and Test 20 10 20 20 10Refine Layout 5 5 5 5 5AutopilotChoose Autopilot System 15 30 10 15 20Choose Transceiver System 10 15 5 5 10Independent Testing/Calibration 40 40 50 20 20Integrate with Aircraft Systems 35 30 30 25 20Re-test/Re-calibrate for In-flight 40 40 50 30 20AccelerometerPCB Design, Layout, and Construction 0 0 0 0 55PCB Independent Testing and Verification 0 0 0 0 50Integration with Launch System and Testing 0 0 0 0 5Total Time 360 260 350 295 320

RESOURCE REQUIREMENTSTABLE 2 - LABOR COST

NAME HOURS RATE TOTAL

Robert Gaul 260 $20.00 $5,200.00

Adam Jacobs 360 $20.00 $7,200.00

Mike Plummer 350 $20.00 $7,000.00

Dan Stone 270 $20.00 $5,400.00

Ronald Teo 300 $20.00 $6,000.00

Cory Tallman 20 $100.00 $2,000.00

Steve Holland 50 $50.00 $2,500.00

TOTAL35300

TABLE 3 - RESOURCE COST

PARTS COSTAutopilot $3,900.00Compass $500.00Ultrasonic Altimeter $500.00Onboard Radio Modem $179.00Video Camera $215.00Camera Lens $80.00Video Transmitter $85.00Power Supply $112.00Batteries $75.00Portable TV $150.00Ground Station Radio Modem $299.00


Video Receiver $100.00Video Receiver Antenna $38.00Radio Modem Antenna $80.00Miscellaneous (Cables and assorted hardware) $200.00TOTAL 6513

TABLE 4 - TOTAL AVIONICS COST ESTIMATE

Labor Cost $35,300.00Resource Cost $6513.00OVERALL TOTAL COST 41813

DELIVERABLES Avionics control system capable of accepting RC Override for manual control, supporting and surviving a vertical catapult

launch, autonomously navigating a preplanned course, controlling an aircraft during vertical catapult launch, and returning telemetry to a ground station

Video system capable of resolving the presence of a 6 inch target at a 100 foot distance, returning video to the ground station

A ground station capable of displaying current aircraft status, accepting input to control aircraft, displaying video data from aircraft, and controlling and coordinating all communication with the aircraft

PROJECT SCHEDULE

F IGURE 3 - PROJECT SCHEDULE GANTT CHART

RISKST E C H N I C A L R I S K S


The major technical risk is how to handle the unique launch method that the customer is asking for (FR08). Because of the short time frame for this project the decision has been made to purchase a commercial autopilot system. The majority of UAV’s are launched at a near-horizontal attitude, making the vertical-launch method of this project relatively unique. This necessitates manual configuration of the autopilot to support the vertical launch system. There is little experience on our team in aerospace applications so it will be beneficial for our team to be able to find and use people with previous knowledge and experience in these areas to assist us in achieving our goals.

Q U A L I T Y R I S K S

Due to the rigors imposed upon the aircraft during the launch phase, it is necessary to design the system and protect internal components to prevent damage due to extreme accelerations.

U S E R A C C E P T A N C E R I S K S

One of the risks in this area is being able to make the product very user friendly. The system will likely be used by novice users in urban environments so it is important the system be very simple to set up and use. It is also imperative that the project be as completely documented as possible to allow the client to understand what was done and allow easier follow-on work from other teams.

S A F E T Y R I S K S

Due to the potentially dangerous nature of the aircraft as well as governmental regulations, we are unable to test the system in the target environment (i.e., a city). During the integration and testing phases, care must always be taken to prevent potential hazards to team members and bystanders as well as to prevent damage to the expensive and sensitive avionics components.

O T H E R R I S K S

Due to the project being a multidisciplinary project there is interdependency between teams. Hence, proper scheduling and deadlines must be met in order to ensure deadlines are met.

Testing of the aircraft may only be performed when weather conditions are favorable. The aircraft is also subject to crashes which may damage avionics components.


DESIGN

DESIGN APPROACHThroughout the design process, we were faced with several overarching ideas to guide our component selection and system design process. First and foremost was the need to meet our functional requirements in the short amount of time allowed to us. After working with faculty and others with experience in UAV’s as well as examining the work of similar projects like MicroCART, we determined that it would be infeasible to design and build an autopilot from scratch and instead chose to integrate commercial products and adapt them to our needs. While this approach did simplify our component design and selection process, it also presented unique concerns in the form of weight and size. It was desirable to select components that had not only the necessary functions and capabilities, but also were as light and small as possible. During the selection process, we also had to choose components that were as supportive of modularity as possible. Thus, we chose to separate our video transmission and autopilot communication channels in order to more easily allow changes to either without affecting the other. Also, we chose a camera that was easy to mount and remove, allowing future users to select a different camera to use in the same airframe and with the same avionics.

SPECIFICATIONST E S T S P E C I F I C A T I O N :

In order to ensure basic system functionality the following testing was performed. While additional testing will be necessary for the autopilot, the following tests specifications were used to assure that the major functional requirements of the Lockheed Martin Challenge UAV could be met. For details regarding actual tests we performed, please reference the “Subsystem Testing” section.

AUTOPILOT SYSTEM:

1) The control loops and parameters in order for the autopilot to operate successfully during launch and normal flight must be determined.

2) Given the control loops and parameters in (1), the autonomous navigation must be simulated and tested.

3) The range and signal quality of the 900MHz radio modem communication system must be verified for use with the autopilot and ground station systems.

4) The autopilot must be properly calibrated to control the servomotors used.

5) Failure conditions for the autopilot system must be considered and tested.

6) Manual override capability must be verified and tested.

VIDEO CAMERA SYSTEM:

1) The resolution of the video camera and lens combination must be verified to meet the functional requirements outlined by Lockheed Martin.

2) The range and signal quality of the 2.4 GHz transmitter and receiver pair must be verified for use with the onboard camera system and ground station.

AVIONICS SYSTEM:

1) Power system endurance must be verified to meet the flight time requirements outlined by Lockheed Martin.


SCHEMATICSSee Appendix A – Schematics for detailed drawings of mechanical and electrical systems.

IMPLEMENTATION

COMPONENTSA U T O P I L O T : M I C R O P I L O T M O D E L 2128

SPECIFICATIONS

Weight: 28g

Dimensions: 100 (L) x 40 (W) x 15 (H) mm

Power Requirements: 140mA at 6.5VDC

Supply Voltage: 4.2-26VDC

CAPABILITIES

This model from MicroPilot includes ground station software (Horizon), can handle up to 1000 waypoints with in-flight modification possible (FR01), and is capable of controlling up to 24 servos simultaneously. The on-board GPS updates at a rate of 4 Hz.

SENSORS

The 2128 provides support for airspeed (up to 500kph), altimeter (up to 12,000 MSL), IMU (3-axis rate gyro/accelerometers), and GPS. The accelerometers saturate at 4 G’s.

DATA COLLECTION AND CUSTOMIZATION

One of the advantages of the MicroPilot model over those offered by other autopilot manufacturers is the ability to utilize user-defined telemetry. It supports up to 16 user-defined PID control loops. Error-handling is user-definable and includes such indications as loss of GPS signal, loss of RC signal, loss of data link, and low battery (NFR02).

The integrated sensors – 4 Hz GPS and compass – provide the necessary data to ensure reliable launch and recovery of the aircraft (FR08). The number of I/O ports and user-defined telemetry allow for unparalleled customization of the autopilot, ranging from a special launch sequence initiation to in-flight refinement of PID control loops to the ability to monitor system performance and power usage. This autopilot also increases the modularity of the design (NFR02) by allowing for a broad range of changes during any future iteration or work on the project. Additional systems or redesigned systems may be easily incorporated into and controlled by the autopilot. This will allow future teams to customize missions to meet their own goals, while still using many systems developed during as part of the current project.

One of the primary limitations of the autopilot, with regard to our current launch sequence and mission, is the relatively low saturation point of the IMU accelerometers (4 G’s). Due to the high G-load, the accelerometers are unreliable during the launch phase. However, this issue can be overcome by implementing a custom launch configuration that does not rely on the accelerometers, but rather, on other peripherals that are unaffected by the G-forces. To do this, we have developed a user-defined PID loop that utilizes the Z-Axis accelerometer (during launch, parallel to the ground) to detect when pitch changes and alter the elevator accordingly. Additionally, the RC override


FIGURE 4 - AUTOPILOT

feature allows for a manual launch and subsequent transition to autopilot control during flight via command from the ground station.

O N - B O A R D R A D I O M O D E M : 9XTEND-SI OEM

SPECIFICATIONS

Weight: 18g

Dimensions: 3.66 x 6.05 x 0.05 cm

Operating Frequency: 900 MHz

Supply Voltage: 4.75-5.5VDC

Max Current: 730mA

CAPABILITIES

The radio modem has a manufacturer-reported outdoor line-of-sight (LOS) range of approximately 14 miles (FR09). Operation on the 900 MHz band isolates transmission and reception of autopilot communications from all other on-board systems, reducing the chance of interference. Utilizing an omni-directional antenna onboard limits our transmission range.

CA M E R A : KT&C M O D E L KPC-650

SPECIFICATIONS

Weight: 137g

Dimensions: 55 (L) x 31 (W) x 31 (H) mm

Power: 180mA at 12VDC

Effective pixels (NTSC): 768 (H) x 494 (V)

CAPABILITIES

Originally chosen in part for its demonstrated ability to perform in unmanned RC aircraft, this fixed-position camera (FR06) has served to meet the surveillance requirements of the project – providing real-time video to the ground station (FR03). The camera is small and relatively lightweight, even with a varifocal lens (NFR03). It draws power from the 12V side of the DC-DC converter, simplifying the power requirements (NFR01). The video output is in standard NTSC format; simplifying the design as no signal conversion is required (the video transmitter and receiver are also NTSC format).

VARIFOCAL LENS

A varifocal lens (Tamron 13VG550ASIISQ 5-50mm) has replaced the original wide-angle fixed lens (the camera is C and CS lens


F IGURE 6 - ONBOARD CAMERA AND LENS

FIGURE 5 - ONBOARD RADIO MODEM

F IGURE 7 - CAMERA RESOLUTION DEMONSTRATION

mount compatible). This greatly increased the modularity of the video system (FR07). When set to wide angle (shorter focal length – around 5mm), the lens provides a wider field of view that is desirable for missions requiring less detail and a broader perspective. When set to telephoto (longer focal length – around 50mm), the lens provides a much narrower, zoomed-in field of view, allowing for the resolution of smaller objects and finer detail. This increase in resolution of small objects allows for a 6 inch target to be discerned from a distance of 100 feet (FR05). The above figure shows the resolution of such an object at a distance of 100 feet, despite low contrast with the background.

The lens is DC auto-iris, meaning that it can automatically compensate the exposure when operating in environments in which the lighting changes frequently. The lens weighs 84g.

V I D E O T R A N S M I T T E R : LA W M A T E M O D E L TM-241800

SPECIFICATIONS

Weight: 30g

Dimensions: 26 x 50 x 13 mm

Power: 500mA at 12VDC

Output: 1 Watt transmission signal

Operating Frequency: 2.4 GHz

CAPABILITIES

The LawMate transmitter contains the maximum power output signal per FCC civilian regulations (1 Watt). The operation of this device requires at least a Technician Class amateur radio license (obtained by one of the team members prior to testing). The transmitter is readily compatible with the on-board camera, as it accepts video data in NTSC format. The standard SMA connector allows for a variety of antennas to be easily interchanged (FR07). The operating frequency is 2.4 GHz, decreasing the possibility of interference with autopilot communication (NFR04).

Of particular importance is the power consumption of this component. While NFR03 states that components should be low-power, the team has deliberately chosen the highest power available. As the primary operating environment of this aircraft is urban, obstructions such as buildings will commonly occur between the aircraft and ground station. To compensate, the transmitter must be extremely high power to ensure the video link is not lost. Additionally, electromagnetic (EM) interference, altitude, and weather will further alter the range of video communications. Ideally, this transmitter can provide a range of two miles when utilizing directional antennas at the ground station. Thus, it is necessary to utilize the most powerful transmitter available to ensure adequate range is achieved (FR09). As an example, many military UAV’s and small aircraft – as they are not bound by civilian regulations – routinely utilize transmitters between two and five watts (or satellite communication links) to increase communications range.

G R O U N D S T A T I O N V I D E O R E C E I V E R : LA W M A T E RX-222480B

SPECIFICATIONS

Weight: 135g

Dimensions: 110 x 70 x 20 mm

Power: 800mA at 5V


F IGURE 8 - ONBOARD V IDEO TRANSMITTER

Operating Frequency: 2.4 GHz

CAPABILITIES

Originally chosen for its portability and compatibility with the video transmitter, this receiver has greatly simplified the power requirements at the ground station for testing. It contains a rechargeable lithium battery, eliminating the need to be externally powered while field-testing. As it is located at the ground station, weight and size were less of a consideration than ability to receive the video signal from the aircraft. Thus, a directional antenna was chosen for use at the ground station to increase the range at which it could still receive a signal. The receiver supports reception on eight channels to minimize signal conflicts in the oft-crowded 2.4 GHz band. Finally, the output is standard RCA composite video format, allowing it to be easily connected to almost any portable display with standard inputs.

G R O U N D S T A T I O N P O R T A B L E D I S P L A Y : A X I O N M O D E L AXN-8701

SPECIFICATIONS


Power: 9VDC

Input: RCA Composite Video Signal

CAPABILITIES

This portable display was chosen for its relatively compact size and ability to accept video in the standard RCA composite output supplied by the video receiver. Additionally, it utilizes a DC voltage input, keeping the ground station power as simple as possible. Furthermore, it contains an internal rechargeable battery, meaning it – like the video receiver – requires no external power during field testing unless run for long periods of time. As the display cannot store video, it must be connected to a VCR or other storage device with the proper RCA inputs if recording the incoming signal for later viewing is desired.

DC-DC C O N V E R T E R : MU R A T A TMP-5/5-12/1-Q12-C

SPECIFICATIONS

Weight: 170g


Output: +5VDC at 5A and +12VDC at 1A

CAPABILITIES

The power requirements of the on-board avionics systems drove the selection of this component. As a


FIGURE 9 – GROUND STATION V IDEO RECEIVER

FIGURE 10 – GROUND STATION PORTABLE TELEVISION

F IGURE 11 - MURATA DC-DC CONVERTER

preference was shown for components with 5VDC or 12VDC input voltages (NFR01), this converter has been able to supply all components on-board the aircraft with appropriate power levels.

G R O U N D S T A T I O N L A P T O P : G A M M A T E C H DU R A B O O K

A Durabook laptop by Gammatech Computer Corporation was purchased for the team to use at the ground station. It is a very rugged design, able to withstand operation in outdoor environments normally deemed hostile to computer electronics. The metal case and internal design make it resistant to spills and drops. The ground station software for the autopilot, Horizon, has been loaded onto the laptop to communicate with the autopilot during flight. The ground station radio modem is connected to the computer to send and receive autopilot communications.

G R O U N D S T A T I O N R A D I O M O D E M : X T E N D -PKG

SPECIFICATIONS

Weight: 200g


Supply Voltage: 7-28V

Max Current: 900mA

Operating Frequency: 900 MHz

CAPABILITIES

Initial research determined this radio modem would be too large to fit in the aircraft, but that it would work well at the ground station to send and receive communications. The outdoor line-of-sight (LOS) range of the modem is 14 miles. The radio modem is connected to the laptop containing the ground station autopilot software – Horizon – to communicate with the aircraft.

LAYOUT AND INTEGRATIONM A I N A V I O N I C S C O M P O N E N T L A Y O U T

In order to facilitate the need for the avionics components to be mounted inside the fuselage in an organized manner, the major components for the autopilot system and video communication system were mounted together onto a common aluminum backing. Attaching the main components onto a common backing allowed for ease in installation into the fuselage as well as the ability to connect the majority of the components together prior to installation into the aircraft. The main avionics component board is pictured below excluding any inter-component wiring.


F IGURE 12 - GROUND STATION LAPTOP

F IGURE 13 - GROUND STATION RADIO MODEM

FIGURE 14 - ASSEMBLED AUTOPILOT LAYOUT

As can be seen in the picture, the autopilot core, servo breakout board, three dimensional compass, ultra-sonic altimeter (AGL), radio modem and video transmitter are all installed onto this common aluminum backing.

Once populated, this board is ready for installation into the aircraft fuselage via three nylon bolts and corresponding T-Nuts which are embedded into the foam core of the internal fuselage structure. Thus, the entire autopilot and corresponding communication system may be installed and uninstalled with the use of only three bolts.

CA M E R A S Y S T E M I N S T A L L A T I O N

In order to install the video camera onto the aircraft it was necessary to keep the functional non-functional requirements of the video system in mind. As outlined, the video system must be modular as well as capable of resolving a 6 inch target from an altitude of 100 feet. Keeping these requirements in mind, an adjustable bracket was constructed allowing for the video camera to positioned and pointed in a variety of configurations as well as allowing for additional lenses and camera styles to be used in the same fuselage. As with the main avionics components board, the video camera mounting bracket was installed into the fuselage using two nylon bolts and corresponding T-Nuts which are imbedded into the foam core of the internal fuselage allowing for quick installation of the unit.

Because of the nature of the belly-style landing of the aircraft it was necessary to mount the camera on the interior of the fuselage. Thus, it was necessary to position a window within the shell of the fuselage for the camera to gaze through. A small piece of transparent polycarbonate was installed into the outer shell of the fuselage to serve as a window for the camera.

P O W E R S Y S T E M I N S T A L L A T I O N

The avionics battery and dc-dc converter were installed into the fuselage using simple Velcro attachments. Again, this allowed for ease of installation and for the avionics battery to be removed without difficulty for charging.

P O W E R S O U R C E S W I T C H I N G C I R C U I T

During initial system and range testing it was determined that it was necessary to design and install a small switching circuit that made it possible to switch the onboard avionics and video components from a ground station power supply to the onboard battery. This switching circuit allows for preflight system checks to be completed without depleting the onboard battery. Once the preflight system checks are completed the circuitry allows the aircraft to seamlessly transition from a


ground based power system to the onboard flight battery. This circuit can be viewed along with the electrical schematics in the appendix of this document.

A N T E N N A E A N D P I T O T T U B E I N S T A L L A T I O N

In order install the video system antenna, radio communication antenna and pitot tube on board the aircraft it was necessary to work closely with aero team to embed the antennae, SMA cables, and pitot tube into the ends of the wing. Below is a picture of the installation of the antennae and pitot tube into the aircraft wing.

F IGURE 15 - ASSEMBLING WING WITH INTERNAL ANTENNAS AND SERVO WIRING

CO M P O N E N T I N T E R C O N N E C T I O N A N D W I R I N G

As components were interconnected modularity and ease of installation were made a priority as well as the limited physical space inside of the fuselage. With these factors in mind, standard disconnects were chosen and installed onto each of the interconnect points between components. Choosing and installing these connectors allowed for each component to be independently installed and removed from the fuselage when necessary with relative ease and without having to repair any soldering that was done to wire the onboard components.

In order to connect devices on either side of the fuselage it was necessary to work with the aero team to choose locations where portions of the internal fuselage core could be removed in order to route wires and connectors from one side of the fuselage to the other.

F I N A L I N S T A L L A T I O N

Below are images of the avionics components fully installed into the fuselage.


F IGURE 16 - AUTOPILOT LAYOUT INSIDE AIRCRAFT

F IGURE 17 - VIDEO SYSTEM INSIDE AIRCRAFT


TESTING

SUBSYSTEM TESTINGA U T O P I L O T

1) Autopilot Verificationa) Individual Sensor Verification

i) We verified the functionality of each individual sensor in the autopilot, including gyros, accelerometers, GPS, pitot tube, pressure altimeter, ultrasonic altimeter, and compass.

b) Orientation Verificationi) Due to the layout of our components in the fuselage our autopilot

was mounted vertically, so we had to alter the autopilot to adjust accelerometer axes and gyros to compensate for the unusual attitude of the board.

c) Programmingi) It was necessary to develop unique code to represent the flight characteristics of our aircraft, including stall

speed, throttle settings, and servo calibrations, among many other values.2) Control Loop and Parameter Determination

a) Efforts were made by the UAV team to develop dynamic models of the aircraft within MATLAB and Simulink in order to calculate PID coefficients prior to flight testing

b) We also used the flight simulator built into HORIZON to develop appropriate flight plans given our flight valuesc) The most efficient and most reliable method of determining PID values is to perform multiple flight tests

i) We were unable to begin flight tests until both the aircraft and launch system were complete.

ii) Weather and pilot availability were limiting factorsiii) Several flights were performed, allowing for work to be done on two PID loops

3) Autonomous Navigation Simulation and Testa) Once flight plans were developed, we utilized HORIZON’s built-in simulator to verify

their behaviorb) After passing this simulation, flight plans were loaded onto the autopilot to verify

code structure and reliabilityc) Flight plans developed for testing were utilized during our PID loop calibration

flights4) Autopilot and Servo Motor Calibration

a) In turn, the autopilot was installed into each of our two airframes with the appropriate tail and wing assemblies.

b) We then calibrated each individual servo in each airframe, saving these calibrations so the autopilot could be used in either aircraft.

c) Calibrations were verified by bench testing with the help of our pilot5) Manual Override Testing

a) During a manual flight, we switched control between autopilot and RC several timesb) This process allowed us both to configure the PID loops but also to verify the functionality of the manual override

feature of the autopilot.


F IGURE 19 - AUTOPILOT TEST LAUNCH WITH ASSEMBLED SYSTEM

F IGURE 18 - BENCH TESTING OF AUTOPILOT

The below images represent data collected by our autopilot during testing. The first image is simply a log of pitch, speed, and altitude during our first test flight. On this graph, it is easy to identify the abrupt forces at work when the craft is launched and close examination can correlate pitch, speed, and altitude as they affect one another, confirming the functionality of the autopilot as a complete system.

-150

-100

-50

0

50

100

150

Autopilot Sensor Data

Pitch (deg)Speed (kts)Altitude (ft)

F IGURE 20 - AUTOPILOT SENSOR DATA

The second image shows the pitch of the aircraft during three different periods of autopilot control (represented by the red highlighted sections) while the autopilot attempted straight and level flight. Taken during our calibration of the pitch PID loop, the data shows that we were able to definitively alter the way the autopilot operated over time, first decreasing the error in pitch calculation and then actually overcompensating for the error. This process proves that it is possible for us to configure the autopilot using our planned method.

V I D E O S Y S T E M


F IGURE 21 - PID CALIBRATION

1) Video Resolution Testa) Several tests of the video system were performed.b) The first involved placing a 6 inch target 100 feet from the camera and lens assembly and verifying that the target

was visible on the displayed image.c) The second test involved mounting the camera on a prebuilt plane to verify functionality of the system while

airborne.d) Our later tests featured the camera system mounted inside one of our airframes to verify the viewing quality of

our fuselage’s window.

CO M M U N I C A T I O N S

1) Autopilot Communicationa) Range testing of the radio modem involved ground-to-ground range

testing between our two radio modems while communicating with the autopilot within our aircraft.

b) Initial tests yielded approximately a ½ mile range before noticeable signal degradation occurred.

c) Safety concerns forced a ground-based test, which was not an accurate analog of real conditions due to unique ground-based concerns, such as a higher frequency of obstacles and changing conditions such as nearby traffic.

d) Major limitation is the FCC regulation governing transmitter power2) Video Communication

a) Range testing of the video system involved ground-to-ground testing between the aircraft and the ground station viewer.

b) Initial tests yielded a range of approximately 1/3 mile.c) Again, FCC regulations limit our ability to extend this range

P O W E R

1) Voltage Testinga) Since we had components operating off 5 and 12 Volts, it was necessary to verify that our DC-DC converter

provided acceptable voltages at differing input ranges.b) We performed a complete battery discharge test while monitoring output voltages of the converter to validate

operation of the converter throughout the battery’s lifetime2) Endurance Testing

a) It was necessary to verify that our power system could allow for our system to operate for approximately the hour timeframe Lockheed required.

b) We performed a full battery discharge test by powering all onboard systems off a battery until they stopped functioning, yielding an endurance of 45 minutes.

c) Lower than requirement, but we were using NiMH batteries for safety during testing. A Lithium Polymer battery would yield much higher endurance and lower weight.


F IGURE 22 - RADIO MODEM TESTING FOR WIRELESS COMMUNICATION

CONCLUSION

ACCOMPLISHMENTSV I D E O S Y S T E M

The onboard video system and corresponding ground station receiver and monitor have been successfully tested and verified. The onboard video systems range and video quality both meet the requirements set forth by our client. The video system has been tested both in a ground setting as well as during flight.

A U T O P I L O T S Y S T E M

The autopilot and ground station systems have been successfully tested and verified with the following major milestones completed:

- Configuration of servos and flight surfaces for the designed aircraft- Communication between the autopilot and ground station during flight - A data log of a radio controlled flight verifying complete in-flight autopilot sensor operation- PID control coefficients for pitch and yaw during level flight tuned- Initial development of custom PID control law for launch phase

I N T E G R A T E D S Y S T E M S

The autopilot and video systems have been installed on the aircraft and an endurance and range test of the combined systems has been completed to verify that both systems may be used in conjunction with one another while still meeting the range and endurance requirements as set forth by the client.

NECESSARY WORKIn order to complete the avionics system and fully integrate it with the UAV and Launch Systems, several aspects of the system must still be refined.

L A Y O U T R E F I N E ME N T

While our current layout works and supports modularity and is relatively lightweight and small, further weight and size savings could be realized through further refinement. Utilization of a smaller aluminum plate or use of a lighter material as well as more efficient wiring could save several ounces.

V I D E O S Y S T E M R E F I N E ME N T

The current video system works and meets Lockheed’s requirements; however it could perform better and provide better data with further work. The addition of a secondary camera with a wide-angle lens could supplement the high-zoom camera to provide more meaningful position data, allowing the camera system to be used for flight control as well as detailed reconnaissance.

A U T O P I L O T

REFINE PID’S

The majority of our testing focused on the Pitch and Yaw PID loops, providing the basis for straight and level fight from the autopilot. Further work needs to be done to calibrate the other PID loops so the autopilot can autonomously navigate.

LAUNCH PHASE


Along with the development of the built-in PID loops, future work could also focus on the development and calibration of custom PID loops to support the vertical launch phase as well as belly landing so the autopilot could fully control the entire flight.


APPENDIX A – SCHEMATICS


APPENDIX B – TEAM INFORMATION

AVIONICS TEAM

A D A M JA C O B S – TE A M L E A D E RE L E C T R I C A L E N G I N E E R I N GA D J A C O B S @ I A S T A T E . E D UP R O J E C T F O C U S : P O W E R S Y S T E M , L A Y O U T

M I K E P L U M M E RCO M P U T E R E N G I N E E R I N GM P L U M M E R @ I A S T A T E . E D UP R O J E C T F O C U S : A U T O P I L O T

R O B E R T G A U LE L E C T R I C A L E N G I N E E R I N GR G A U L 8@ I A S T A T E . E D UP R O J E C T F O C U S : V A R I O U S

R O N A L D T E OCO M P U T E R E N G I N E E R I N GN I M R A C K @ I A S T A T E . E D UP R O J E C T F O C U S : V A R I O U S

DA N I E L S T O N EE L E C T R I C A L E N G I N E E R I N GS T O N E D A N @ I A S T A T E . E D UP R O J E C T F O C U S : V I D E O S Y S T E M

LAUNCH TEAM

JE N BY E RM A T E R I A L S E N G I N E E R I N GJ B Y E R @ I A S T A T E . E D U

R E I D S C H E N KM E C H A N I C A L E N G I N E E R I N GR S C H E N K @ I A S T A T E . E D U

BR I A N C H E N E YM E C H A N I C A L E N G I N E E R I N GB C C H E N E Y @ I A S T A T E . E D U

HA R R I S O N BU C YM E C H A N I C A L E N G I N E E R I N GH B U C Y @ I A S T A T E . E D U

UAV TEAM

T R A V I S G R A G E R – PR O J E C T L E A D E RA E R O S P A C E E N G I N E E R I N GT G R A G E R @ I A S T A T E . E D U

N I C K W U L K EA E R O S P A C E E N G I N E E R I N GN W U L K E @ I A S T A T E . E D U

A L I C I A K U H L M A NA E R O S P A C E E N G I N E E R I N GA M K U H L M @ I A S T A T E . E D U

T O M R A M E YA E R O S P A C E E N G I N E E R I N GT O M R A M E Y @ I A S T A T E . E D U


Lockheed Martin Challenge Avionics Final...

Documents

Transcript of Lockheed Martin Challenge Avionics Final...