Osamah Rawashdeh

Design and Implementation of Embedded Printed Antenna Arrays in Small UAV Wing Structures

Unmanned aerial vehicles (UAV) are extensively being used in exploration, surveillance and military applications. Such vehicles often collect data via special sensors and send the data back to the central station via wireless links. Embedded in wing structure printed antennas will eliminate the drag due to friction, and allow for extended load capability due to their extra light weight. In this work we present the design and implementation of a 4-element linear antenna array embedded in a small UAV wing structure. The antenna array operates in the 2.4 GHz ISM band. Simulations and measurements that characterize the performance of the antenna array are presented. Field measurements show the impact of utilizing beam-forming in enhancing the communication link throughput.

A Technique for Specifying Dynamically Reconfigurable Embedded Systems

This paper describes a framework for developing dynamically reconfiguring distributed embedded systems supporting graceful degradation. Graceful degradation allows embedded systems to reconfigure in response to faults, allowing the systems to reduce their level of service instead of suffering system failures. The approach is based on a graphical software specification technique. Software module dependency graphs are used to specify the interaction and interdependencies between software modules. Individual software modules can be specified with alternate implementations that may require different amounts of system resources. As failures occur, a system manager tracks system status and uses the dependency graphs to choose new system configurations to deploy. The proposed framework also supports traditional fault-tolerance techniques, such as fail-over programming, redundant calculations, and voting, making it an attractive alternative for the design of a wide range of embedded control applications. A high level description of the proposed system architecture as well as its fault detection and handling are presented followed by discussion of the software modeling

BIG BLUE: high-altitude UAV demonstrator of Mars airplane technology

BIG BLUE (baseline inflatable-wing glider, balloon-launched unmanned experiment) is a flight experiment envisioned, designed, built, and flown primarily by undergraduate students in the College of Engineering at the University of Kentucky. BIG BLUE was conceived as a demonstration of unique inflatable wing technologies with potential for application for Mars airplanes. On May 3, 2003, BIG BLUE achieved the first-ever deployment and curing of UV hardening inflatable wings and reached an altitude of 27.1km (89,000ft). BIG BLUE II was launched successfully on May 1, 2004 with a second-generation optimized wing design. The wings were deployed and cured to an excellent symmetric flying shape from a flight ready fuselage with an autonomous autopilot, sensor and communication systems. To date, over 100 students have participated directly in the design, fabrication and testing of BIG BLUE, exposing them to the challenge and excitement of aerospace careers. BIG BLUE is supported by the NASA Workforce Development Program which has objectives to attract, motivate, and prepare students for technological careers in support of NASA, its missions, and its research efforts. BIG BLUE provides multidisciplinary experiential learning directed specifically toward entering the aerospace workforce

BIG BLUE II: Mars Aircraft Prototype with Inflatable-Rigidizable Wings

The present paper presents work on developing and flight testing a Mars prototype aircraft using inflatable-rigidizable wings under the NASA Workforce Development program. Undergraduate student teams have developed a test vehicle to determine the feasibility of using inflatable-rigidizable wings in extra-terrestrial missions. The wings are constructed of an outer composite layer impregnated with a UV curable resin and an inner inflatable bladder. The wings are stowed in the fuselage, deploy when inflated, and rigidize with exposure to UV radiation; pressurization is not required after rigidization. Vehicle, wing and avionics designs are discussed and results from low and high altitude test flights are presented. The project culminated in a successful high altitude flight test with deployment and rigidization of the wing under Mars like conditions.

MICRORAPTOR: A LOW-COST AUTONOMOUS QUADROTOR SYSTEM

This paper describes Microraptor, a complete low-cost autonomous quadrotor system designed for surveillance and reconnaissance applications. The Microraptor ground station is custom-made and features a graphical user interface that presents and allows the manipulation of various flight parameters. The aerial vehicle is a 4-rotor vertical takeoff and landing (VTOL) vehicle that features the advantages of traditional helicopters with significant reduction in mechanical complexity. The vehicle frame is a handmade magnesium and carbon fiber structure. The onboard avionics system is a custom dual processor design capable of autonomous path navigation and data exchange with the ground station. The vehicle is outfitted with a video and still-photo system that provides real-time images to the system operator through the GUI. The system is being developed at Oakland University by a team of multidisciplinary undergraduate and graduate engineering students. Microraptor placed 5th at the 2008 Association for Unmanned Vehicle Systems International (AUVSI) Unmanned Aerial Systems (UAS) Competition and is set to compete again in June of 2009.Copyright

Precision instrument for characterizing shape memory alloy wires in bias spring actuation

Some metallic alloys such as Nitinol (NiTi) exhibit the shape memory effect, which is suitable for generating force and displacement when the alloy changes phase during a heating and cooling cycle. These shape memory alloys are often formed into one-dimensional wires, tubes, and ribbons that are preloaded by bias springs to create inexpensive actuators for electromechanical devices. This article describes a new instrument for measuring the quasistatic characteristics of the alloy and the transient performance of bias-spring actuators when resistively heated and convectively cooled. The instrument achieves more accurate measurements by eliminating rolling friction and by sensing force and displacement in line with the bias spring and shape memory alloy wire. Data from the instrument enables calculation of stress and strain at constant temperatures and during actuation cycles.

A Low-Cost Control System for a High-Altitude UAV

The BIG BLUE project at the University of Kentucky is a test bed UAV for Mars airplane technology. A major focus of the BIG BLUE effort has been the development of a low-cost and light-weight avionics, control, and communication system to manage the aircraft and correspond with ground stations. BIG BLUE I, launched in May 2003, achieved the first successful deployment of inflatable/rigidizable wings at altitude. BIG BLUE II, launched in May 2004, had a flight-ready fuselage and control system. This paper describes the BIG BLUE project detailing the design and implementation of the avionics, control, and communication system

Evolution of an Avionics System for a High-Altitude UAV

The UAV Research Group at the University of Kentucky is developing a test-bed UAV platform for Mars airplane technology, dubbed BIG BLUE. A major focus of the BIG BLUE effort has been the development of a low-cost and light-weight avionics, control, and communication system to manage the aircraft and relay data between the UAV and the ground stations during long-range high-altitude missions. BIG BLUE I, launched in May 2003, achieved the first successful deployment of inflatable/rigidizable wings at altitude. BIG BLUE II, launched in May 2004, had a flight-ready fuselage and control system. BIG BLUE 3 employed a new wing design and an enhanced avionics suite. This paper discusses the history of the BIG BLUE avionics, control, and communication systems, as well as the continuing design changes for future phases of the project.

Rapid Prototyping of Quadrotor Controllers using MATLAB RTW and dsPICs

This paper presents a rapid prototyping approach to attitude control algorithms of a quadrotor aerial vehicle. The MATLAB’s Simulink Real Time Workshop (RTW) is used to implement closed loop PID control algorithms for vehicle roll, pitch, and yaw stabilization. The graphical environment of Simulink allows developers to easily implement and tune complex control algorithms. Moreover, RTW automatically generates executable C code for Microchip dsPIC embedded processors. The performance of several control loops is evaluated experimentally.

Performance of an embedded monopole antenna array in a UAV wing structure

In this work we present a small size, printed monopole antenna embedded within the wing structure of a small Unmanned Aerial Vehicle (UAV) and operating in the 2.4 GHz ISM band. Integration of antenna elements within UAV structures will reduce the weight and cost. Also, the use of embedded antenna arrays will increase the communication range and data throughput. 4-element and 8-element embedded uniform linear antenna arrays are modeled, simulated and studied. Simulation and measurement results for the resonant frequency of the basic element were performed. Results showing the HPBW and SLL of the simulation models for different excitations for the wing structure antenna array are presented and compared.