Daniel P. Schrage

The Georgia Tech Unmanned Aerial Research Vehicle: GTMax

This paper describes the design, development, and operation of a research Unmanned Aerial Vehicle (UAV) system that has been developed at the Georgia Institute of Technology, called the GTMax. This description will include the processes put in place to enable the system to be used for UAV-technology research, including effective flight testing. Research UAVs are characterized by the need for continual checkout of experimental software and hardware. Also, flight-testing can be further leveraged by complementing research results with flight-test validated simulation results for the same experimental UAV platform. The chosen helicopter-based UAV platform (a Yamaha R-Max) is well instrumented, including: differential GPS, inertial measurement unit, sonar altimeter, radar altimeter, and a 3-axis magnetometer. One or two flight processors can be utilized.

System Integration and Operation of a Research Unmanned Aerial Vehicle

Published in Journal of Aerospace Computing, Information, and Communication, Vol. 1, Issue 1, January 2004.

Application of Probabilistic Methods for the Determination of an Economically Robust HSCT Configuration

Presented at the 6th AIAA/NASA/USAF/ISSMO Symposium on Multidisciplinary Analysis and Optimization, Bellevue, WA, September 4-6, 1996.

Statistical Experimentation Methods for Achieving Affordable Concurrent Systems Design

We describe an affordable method for designing in the conceptual stage using relatively high-fidelity concurrent systems analysis. Our method is rooted in three domains, namely, the design of experiments, the response surface methodology, and the compromise decision support problem. A sequential experimentation strategy as well as the heuristic rules for creating high-order response surface models are introduced as a cost-effective approach to applying the statistical experimentation methods in design of complex systems. A high-speed civil transport aircraft design is used as an example to illustrate the potential of our approach.

An open control platform for reconfigurable, distributed, hierarchical control systems

Complex control systems for autonomous vehicles require integrating new control algorithms with a variety of different component technologies and resources. These components are often supported on different types of hardware platforms and operating systems and often must interact in a distributed environment (e.g., in communication with a groundstation, mothership, or other UAVs in a swarm). At the same time, the configuration and integration of components must be flexible enough to allow rapid online reconfiguration and adaptation to react to environmental changes and respond to unpredictable events during flight, such as avoiding a moving obstacle or recovering from vehicle equipment failures. This paper describes an open software architecture, called the open control platform, for integrating control technologies and resources. The specific driving application is supporting autonomous control of VTOL uninhabited autonomous vehicles.

A Hierarchical Aircraft Life Cycle Cost Analysis Model

Presented at the 1st AIAA Aircraft Engineering, Technology, and Operations Congress, Anaheim, CA, September 19-21, 1995.

Nonlinear adaptive control of a twin lift helicopter system

The tracking control of a twin-lift helicopter system in the presence of parametric uncertainty is considered. A nonlinear model is used to describe the dynamics of a twin-lift helicopter configuration in the lateral/vertical plane, and a controller is synthesized using an input-output feedback linearization technique in conjunction with an adaptation algorithm. The control scheme does not require any knowledge of the bound of uncertainties present and drives the output tracking error to zero asymptotically. The performance of the controller is illustrated by simulating the nonlinear model of the twin-lift system.<<ETX>>

An open software infrastructure for reconfigurable control systems

Recent advances in software technology have the potential to revolutionize control system design. This paper describes a new software infrastructure for complex control systems, which exploits new and emerging software technologies. It presents an open control platform (OCP) for complex systems, including those that must be reconfigured or customized in real-time for extreme-performance applications. An application of the OCP to the control system design of an autonomous aerial vehicle is described.

COMBINED AERODYNAMIC AND STRUCTURAL OPTIMIZATION OF A HIGH-SPEED CIVIL TRANSPORT WING

A combined procedure for the aerodynamic and structural optimization of a High-Speed Civil Transport wing is presented. Primary goal of the procedure is the determination of the jig shape of the wing necessary so that it deforms into its optimum shape in cruise flight. The wing twist and camber distribution is optimized for the cruise condition using WINGDES, a code based on a linearized potential flow solution for zero-thickness lifting surfaces. The structural design is decomposed into three levels. The top level uses the FLOPS aircraft synthesis program to generate preliminary weights, mission, and performance information. The optimization criterion is productivity expressed by a productivity index for the specified mission. The second level of the system performs a finite-element based structural optimization of the wing box with the help of the ASTROS structural optimization tool. The wing structure is sized subject to strength, buckling, and aeroelastic constraints. The buckling constraint information is supplied by the third level where a detailed buckling optimization of individual skin cover panels is performed. The Georgia Tech HSCT baseline aircraft is presented and the resulting optimum wing structure, cruise and jig shapes are explained in detail. Nomenclature

UAV Flight Test Programs at Georgia Tech

This paper describes the design, development, and operation of research Unmanned Aerial Vehicles (UAVs) that have been developed at the Georgia Institute of Technology in the Schools of Aerospace and Electrical/Computer Engineering. This includes a description of flight test experiences and lessons learned over the past 10 years, with emphasis on recent work. Specifically in 1998, Georgia Tech acquired a Yamaha R-Max Remotely Piloted Helicopter (RPH) for use in the DARPA Software Enabled Control and other research programs. An open system UAV testbed was developed based on this vehicle that is referred to as the GTMax. The use of a variety of simulation configurations has been of considerable benefit. Flexible data communication systems, models for all hardware components, and a flexible simulation software infrastructure are important. The use of a modular avionics architecture and the use of a vehicle with a relatively large payload capacity also allow these UAVs to be configured quickly for a variety of experiments.