SAE TECHNICAL PAPER SERIES 2000-01-2100 Analysis of Aerobatic Flight Safety Using Autonomous Modeling and Simulation Ivan Y. Burdun Georgia Institute of Technology Oleg M. Parfentyev Siberian Aeronautical Research Institute Reprinted From: Proceedings of the 2000 Advances in Aviation Safety Conference (P-355) Advances in Aviation Safety Conference and Exposition Daytona Beach, Florida April 11-13, 2000 400 Commonwealth Drive, Warrendale, PA 15096-0001 U.S.A. Tel: (724) 776-4841 Fax: (724) 776-5760 The appearance of this ISSN code at the bottom of this page indicates SAE’s consent that copies of the paper may be made for personal or internal use of specific clients. This consent is given on the condition, however, that the copier pay a $7.00 per article copy fee through the Copyright Clearance Center, Inc. Operations Center, 222 Rosewood Drive, Danvers, MA 01923 for copying beyond that permitted by Sec- tions 107 or 108 of the U.S. Copyright Law. 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Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. A process is available by which discussions will be printed with the paper if it is published in SAE Transactions. For permission to publish this paper in full or in part, contact the SAE Publications Group. Persons wishing to submit papers to be considered for presentation or publication through SAE should send the manuscript or a 300 word abstract of a proposed manuscript to: Secretary, Engineering Meetings Board, SAE. Printed in USA 2000-01-2100 Analysis of Aerobatic Flight Safety Using Autonomous Modeling and Simulation Ivan Y. Burdun Georgia Institute of Technology Oleg M. Parfentyev Siberian Aeronautical Research Institute Copyright © 2000 Society of Automotive Engineers, Inc. ABSTRACT 110° (“Pougatchev Cobra”) [2]. Cobra and other unique aerobatic figures performed to date represent an emerg- An affordable technique is proposed for fast quantitative ing class of new flight maneuvers, which will drastically analysis of aerobatics and other complex flight domains expand the operational domain of next generation air- of highly maneuverable aircraft. A generalized autono- craft. mous situational model of the “pilot (automaton) – vehicle – operational environment” system is employed as a “vir- tual test article”. Using this technique, a systematic knowledge of the system behavior in aerobatic flight can be generated on a computer, much faster than real time. This information can be analyzed via a set of knowledge mapping formats using a 3-D graphics visualization tool. Piloting and programming skills are not required in this process. Possible applications include: aircraft design and education, applied aerodynamics, flight control sys- tems design, planning and rehearsal of flight test and dis- play programs, investigation of aerobatics-related flight accidents and incidents, physics-based pilot training, research into new maneuvers, autonomous flight, and onboard AI. INTRODUCTION Fig. 1. Example of an aerobatic display sequence for a highly maneuverable aircraft PROBLEM – Aerobatic flight is one of the most spectacu- lar air display events, a perfect example of coherent man- At the same time, these new technologies increase the machine interaction. Aerobatics is a synthesis of the likelihood of flight accidents with highly maneuverable air- capabilities of a highly maneuverable flying machine and craft. One of the main reasons is the limitations and an experienced human pilot (Fig. 1). Display flights of shortcomings of a human pilot’s knowledge, decision- advanced aircraft invariably attract thousands of people making and physical capabilities revealed under extreme to major national and international air shows every year conditions of aerobatics. A demand is growing for new [1]. The problem of aerobatic flight safety, however, research methods and tools, which could help enhance remains unresolved. There have been several aerobat- the processes of design, test, pilot training, accident ics-related flight incidents and incidents with new and old analysis and prevention, and flight control of highly aircraft types recently and in the past. maneuverable aircraft. Flight test and manned simulation Advances in high-angle-of-attack, low-speed aerodynam- have limitations when a detailed, systematic examination ics, adaptive flight control and thrust vectoring [2-5] have of a complex flight domain, such as aerobatic maneuver- opened a new era in aerobatic flying. In 1989 Victor Pou- ing, is essential [6]. More affordable and faster methods gatchev, a Russian test pilot flying a Sukhoj-27 fighter, are therefore needed for this purpose. Thus, the problem had demonstrated a spectacular Cobra maneuver, first under study is formulated as follows: (1) techniques for achieving in horizontal flight pitch angles exceeding 80°- fast, inexpensive and efficient analysis of aerobatic flight, 1 and (2) virtual test and evaluation of aerobatic flight per- vehicle- or case-specific piloting instructions or flight formance of a highly maneuverable aircraft using these safety recommendations for immediate use. Some nota- techniques. tions and concepts, used or introduced in this study, may differ from related national standards. The following factors may compromise aerobatic flight safety: a highly dynamic 4-D maneuvering environment, PAPER STRUCTURE – The paper includes the following performance of flight and control at and beyond the edge main sections: a brief description of the employed virtual of the vehicle’s normal operational envelope, ground test article; a description of the employed aerobatic sce- proximity, extreme physical and mental workload experi- nario (example); results of aerobatic modeling and simu- enced by the pilot, last-minute changes made to a pre- lation, including examples of identified unsafe and planned display scenario, lack of pilot’s or designer’s hypothetical maneuvers; a brief discussion of results; knowledge of the vehicle behavior in non-standard conclusions. Several supplementary tabular and graphic (multi-factor) situations, and unforeseen obstacles (birds, materials are located in Appendix. other aircraft, etc.). Negative effects of these factors, including the potential for “chain reaction” – a spontane- VIRTUAL FLIGHT TEST ARTICLE ous, irreversible transition of a safe flight towards a catas- trophe [7], must and can be examined in advance. AIRCRAFT TYPE – In this study, the virtual test article under study is a mathematical model of a highly maneu- SOLUTION APPROACH – One possible solution verable notional jet fighter or trainer, which summarizes approach to this problem, called autonomous situational key features of modern highly maneuverable aircraft. In modeling and simulation of flight, is introduced below. A particular, the model has advanced low-speed aerody- hypothetical yet realistic aerobatic flight scenario is namics, which permits operational use of high angles of employed to demonstrate this technique. It is based on attack and pitch (up to 90°-135°). The “aircraft” is two concepts: an AI situational pilot model and a flight sit- equipped with two engines, providing a maximum thrust- uation scenario [8, 9]. The words “autonomous” and “situ- to-weight ratio of about 1.15-1.3 (at SL). It also has a 2-D ational” mean that a human pilot’s decision-making thrust vectoring capability for flight path and attitude con- mechanism and the content of aerobatic flight situations trol at low and medium speeds. (maneuvers) are modeled mathematically, together with the vehicle flight dynamics. This enables flexible plan- FLIGHT CONTROLS – The vehicle’s primary flight con- ning, fast-time execution, and, if necessary, multiple repe- trols include canards coupled with elevator, ailerons, rud- titions (in exact detail or modified) of various aerobatic der, throttles, and 2-D thrust vectoring nozzles. The sequences on a PC. Piloting and programming skills are model’s secondary control devices are: flaps coupled not required in this process. with slats, interceptors, airbrakes, undercarriage control (extended, interim, and retracted positions), thrust revers- OBJECTIVE – The subject of this study is identification of ers, and main wheel brakes. complex cause-and-effect relationships in the “pilot (automaton) – vehicle – operational environment” system DESIGN PARAMETERS – Selected design parameters behavior under aerobatic flight conditions. Another of the model are shown in Table 1. research focus is new graphic formats for mapping knowl- edge of a complex flight domain in simulation.