Aerospace Control and Guidance Systems Committee

Meeting 107

AFRL Control Science Overview 4.1.1.1 AFRL Abstract - Oppenheimer.docx

• The AFRL Control Science Center of Excellence conducts research in three broad areas, Multi UAV Control, Flapping Wing Micro Air Vehicle Dynamics and Control, and Hypersonic Vehicle Dynamics and Control. The focus of this particular overview is on the activities associated with the Multi UAV Control Group and their participation in the Joint US-Australia Talisman Saber Exercise. The group used Vigilant Spirit Ground Control stations and multiple small UAVs to provide aerial surveillance to select participants in the exercise. They demonstrated the ability to fly cooperative missions with 4 UAVs under the control of the Vigilant Spirit Control Station at the Command Post (CP) and with forward deployed teams equipped with laptops. Cooperative control tools managed the activities resulting in the identification of hundreds of vehicles on roads and under camouflage. The system also indentified types & numbers of aircraft on airfields and identified beach landing areas and sited blue force assets. In total, the group flew 71 sorties - 64 flight hours with no mishaps.

Controls Research at the United States Air Force AcademyTom Cunningham

Department of AeronauticsThe US Air Force Academy has the mission of cadet based research for the education of future Air Force officers. To that end the Department of Aeronautics faculty members direct all cadets in the department in real work research projects of interest to US government aerospace needs. This involves cadets working in one of the numerous wind tunnels at USAFA. Most projects are funded by military or NASA sponsors. Examples are damage repair tabs for the A-10 and parachute dynamics for the NASA Orin return vehicle.

4.1.2 Federal Aviation Administration – Stan Pszczolkowski

In March 2011 the FAA will publish two key planning documents: “2011 Update to the NexGen Implementation Plan” and “Destination 2025”. The former is a key external outreach document that was developed with stakeholder involvement. The later, which replaces the “Flight Plan”, is the FAA’s long term strategic vision. It contains 5 goal area, metrics and a clear integration with NextGen. Transformation imperatives include the optimization of shared services, the upgrade strategic capabilities, realignment in support of NextGen, collaboration and the building of a “One FAA” culture. The FAA recently published the “FAA 2010 Performance and Accountability Report” (http://www.faa.gov/about/plans_reports/media/2010_PAR.pdf). The agency met 28 of 31 targets in Safety, Capacity, International Leadership and Organizational Excellence.

Field site testing of the Enroute Automation Modernization (ERAM) system continues. It will be operational at all 20 Air Route Traffic Control Centers by the end of 2013. ERAM, a critical NextGen foundation effort, will replace an air traffic control automation capability that includes 1990s hardware and 1960s-2000s software (BAL and JOVIAL). ERAM has over 1,800,000 source lines of code in C, C++ and ADA, equally split between new/modified and reused.

Government Agencies Summary Reports – NASA LangleyMarty Waszak

Deputy DirectorOffice of Center Chief Technologist

NASA Langley Research CenterHampton, VA

AbstractRecent accomplishments at Langley cover a wide range of flight dynamics and control topics including launch vehicles, flexible aircraft, next generation air traffic operations, and probabilistic control analysis and design. methods The Max Launch Abort System (MLAS) is an alternate launch abort system concept for future human space exploration. MLAS involves a number of control challenges including static and dynamic instability, highly nonlinear effectors, and control allocation. A key challenge of large supersonic aircraft is the effect of dynamic aeroelastics on flying qualities. A simulation study is underway to assess pilot-vehicle coupling. The challenges of NextGen air traffic management involve increasing capacity while also improving safety. Several studies are ongoing and planned to increase capacity by using synthetic/enhanced vision systems, weather avoidance management, ADS-B, and runway configuration management. A new technique has been developed to design control systems taking into account parametric uncertainties. UQ Tools is a collection of Matlab tools to substantially reduce the cost and time required for Monte Carlo analyses to assure close loop performance under parametric uncertainty. Application of UQ Tools to relevant problems is underway and a beta version of the UQ Tools toolbox is available.

NASA GRC Research in Intelligent Propulsion Control and DiagnosticsABSTRACT 4.1.3.2 NASA GRC Abstract - Garg.docx

With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. Also the propulsion systems required to enable the NASA future human space exploration activities in an affordable manner will need to have high reliability, safety and autonomous operation capability. The Controls and Dynamics Branch at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet these challenges through the concept of Intelligent Propulsion Systems. This presentation describes some of the key current activities of the Controls and Dynamics Branch (CDB) under the NASA Aeronautics Research and Exploration Systems Missions. The programmatic structure of the NASA Aeronautics Research Mission is briefly discussed and the new program management structure for Aeronautics Programs is overviewed.

The activities covered in the presentation include: i) Recent GRC accomplishment in demonstration of active suppression of combustion instability for a low emission prototype combustor; ii) Research on an enhanced gas path diagnostics architecture which is based on the use of a real-time on-board engine model which adapts to changes in engine condition; iii) Development of a risk assessment architecture to implement enhance engine response control modes for emergency operation.

Government Agencies Summary Reports – NASA DrydenSteve Jacobson

NASA Dryden Research CenterEdwards, CA

Abstract NASA Dryden has been recently completed several major activities in controls and dynamics. This presentation highlights this work as well as ongoing work and future research and technology development. The most recent significant activity recently completed was flight research that culminates a multi-year effort in development of adaptive control technologies for piloted vehicles. The research computers for the NASA FAST aircraft were used for this research. Additionally this presentation gives a status on the upcoming research in control of flexible structures, Autonomous Aerial Refueling with the global hawk aircraft, SOFIA’s recent ‘first light’ accomplishment, and upcoming flight activities in hypersonics and automatic collision avoidance technology.

Eric FeronGeorgia Institute of Technology

Controls at Georgia TechThe controls research group at Georgia Tech includes more than 16 professors, distributed across many schools, including Aerospace, Mechanical, and Electrical and Computer Engineering. Working with their advisors, a large body of undergraduate and graduate students is addressing a variety of subjects of aerospace interest. These projects include extensive flight testing activities for vision-based flight, human factor studies for human assisted moon-landing procedures, planning of aggressive trajectories for land and air vehicles, innovative autonomous vehicle design, air transportation and real-time software analysis and design. With such a range of activities, Georgia Tech, together with the Georgia Tech Research Institute, is an important player in aerospace control and autonomy research.

Dave Schmidt,Professor EmeritusUniversity of Colorado

A new book entitled Modern Flight Dynamics will be published by McGraw-Hill in March 2011. The almost 900-page offering is written as a textbook for senior-level engineering undergraduates who have been introduced to intermediate dynamics, aerodynamics, and classical feedback control. The text contains many examples and exercises, using data for several aircraft, and makes copious use of MATLAB/Simulink. Many MATLAB routines related to the examples are made available to the reader. Though easily followed by undergraduates, the book is a more rigorous work than many existing texts, especially with regard to the derivations of the nonlinear equations of motion in several reference frames, as well as the treatment of direction-cosine matrices, small-perturbation theory, and linear-

systems analysis. Three chapters address the modeling of the forces and moments on the vehicle, plus static and dynamic aeroelastic effects are treated extensively in the presentation, including a case study on active structural mode control of the B-1 aircraft. Feedback-stability augmentation is directly tied to, and motivated by the results from the linear analysis of the vehicle’s dynamics. Common autopilot modes (e.g., heading hold, ILS couplers) and the crossover pilot model are all presented in the context of conventional loop shaping. Hence, the work could also be a useful reference for practicing professionals. Finally, the author would like to recognize the contributions of many members of the ACGSC that were significant to the development of this book.

Gary BalasAerospace Engineering and Mechanics

University of MinnesotaThe Department of Aerospace Engineering and Mechanics. aerospace engineering doctoral program has been placed fourth in the nation overall in the recently released 2010 National Research Council (NRC) Assessment of Doctoral Research Programs. The program was second in the specific categories of Research Activity and Student Support.The Aerospace Engineering and Mechanics at the University of Minnesota has recently had the grand opening of their beautifully and newly renovated hangar for Akerman Hall. The original hangar was constructed in 1952. The renovated hangar has a live web camera athttp://aem.umn.edu/hangar/camera.shtmlTwo new research programs on aeroservoelastic control supported by NASA have been initiated. UMN AEM has a NASA STTR with Tao Systems on Robust Aeroservoelastic Control Utilizing Physics-Based Aerodynamic Sensing.Independently, MUSYN received a NASA SBIR Phase I on Adaptive Linear, Parameter Varying Control for Aeroservoelastic Suppression.

Rockwell CollinsVlad Gavrilets

Athena Technologies, after acquisition by Rockwell Collins in April 2008, has been renamed Rockwell Collins Control Technologies (RCCT). RCCT has continued expansion beyond its core business of providing guidance, navigation, and control systems for unmanned aircraft into several other areas: engine control units, azimuth determination and tracking units for ground-based far target locators, FAA-certified cockpit avionics for manned aircraft and helicopters, and precise GPS positioning. Presentation features several new RCCT products on the market.

In the original core business, RCCT successfully completed its Damage Tolerant Flight Control on an operational UAV; exceeded 1,000,000 flight hours in theater with its Athena product line of integrated flight control, navigation, and vehicle management systems; and completed over 200 flight hours on its new low-cost triplex redundant flight control system. This system is based on triplex redundant Athena units, used for state vector estimation, and a newly designed General Purpose Computer (GPC1000), a ruggedized industrial computer with expansive I/O, used for flight control calculations and redundancy management.

Louis H. Knotts, President

Calspan Corporation Current work on going within the Flight Research Group of Calspan includes flight test work supporting Unmanned Air Vehicle research, Piasecki Helicopter X-49A modifications to add a Programmable Flight Control system, a Boeing offset program for the Republic of Korea, and some collaboration projects with STI. The Unmanned Air Vehicle flight test utilizes the Calspan variable stability Learjets to conduct flight test in support of the Automatic Aerial Refueling and Sense and Avoid projects. This is a multi-year effort and will continue through 2011. The X-49A projects expands the yaw axis programmable flight control system that was added last year into an all axis programmable flight control system to improve handling qualities and reduce pilot workload. The Boeing offset program includes development of a Genesis engineering ground simulator, a Learjet simulation project of a Korean aircraft, and in-country training.

Hoh Aeronautics, Inc. Research Update

HAI is in the final stages of development of an expert system for the application of ADS-33E-PRF, the military specification for rotorcraft handling qualities. Under a Phase II.5 SBIR from NAVAIR, the ADS-33 Specification Assistance Package (ASAP) will pre-process input data from many different sources and formats; compute time- and frequency-response parameters; and assist the user with interpreting the results when those parameters are compared with the requirements of ADS-33E-PRF. A Beta version of the software, running in MATLAB, should be released this Fall.

In support of the ASAP development, HAI is helping the Navy in flight test evaluations of handling qualities of large cargo helicopters, focusing on slung-load operations. Testing is ongoing at Patuxent River with a CH-53E. HAI is also developing a display system for evaluations of handling qualities for helicopter shipboard launches and recoveries. Based around the Superslide developed by the Canadian National Research Council, the portable display will be an electronic board that will be programmable for different ship motions and Sea States.

HeliSAS, the low-cost, lightweight helicopter SAS system developed by HAI, is finally about to get an FAA Supplemental Type Certification for the Bell 206, and more STC’s should follow shortly.

HAI has just completed a survey of UAV designers and users for the Navy. This survey confirmed the need for dedicated UAV flying characteristics design criteria and requirements.

Dave Mitchell, the Technical Director at HAI for the past 17 years, has left the company to start his own business part-time, and to work for another small business part-time.

Hoh Aeronautics, Inc. Research Update

HAI is in the final stages of development of an expert system for the application of ADS-33E-PRF, the military specification for rotorcraft handling qualities. Under a Phase II.5 SBIR from NAVAIR, the ADS-33 Specification Assistance Package (ASAP) will pre-process input data

from many different sources and formats; compute time- and frequency-response parameters; and assist the user with interpreting the results when those parameters are compared with the requirements of ADS-33E-PRF. A Beta version of the software, running in MATLAB, should be released this Fall.

In support of the ASAP development, HAI is helping the Navy in flight test evaluations of handling qualities of large cargo helicopters, focusing on slung-load operations. Testing is ongoing at Patuxent River with a CH-53E. HAI is also developing a display system for evaluations of handling qualities for helicopter shipboard launches and recoveries. Based around the Superslide developed by the Canadian National Research Council, the portable display will be an electronic board that will be programmable for different ship motions and Sea States.

HeliSAS, the low-cost, lightweight helicopter SAS system developed by HAI, is finally about to get an FAA Supplemental Type Certification for the Bell 206, and more STC’s should follow shortly.

HAI has just completed a survey of UAV designers and users for the Navy. This survey confirmed the need for dedicated UAV flying characteristics design criteria and requirements.

Dave Mitchell, the Technical Director at HAI for the past 17 years, has left the company to start his own business part-time, and to work for another small business part-time.

Recent Activities at Systems Technology, Inc.David Klyde dklyde@systemstech.comFused Reality Flight for Enhanced Flight Test CapabilitiesIn terms of relevancy to piloted evaluation, there remains no substitute for actual flight tests evenwhen considering the fidelity and effectiveness of modern ground-based simulators. In additionto real world cueing (vestibular, visual, aural, environmental, etc.), flight test provides subtle butkey intangibles that cannot be duplicated in a ground-based simulator. There is, however, a costto be paid for the benefits of flight in terms of budget, mission complexity, and safety includingthe need for ground and control room personnel, additional aircraft, etc. New technologies andtest procedures are therefore needed to maximize the investments and reduce some of the relatedcosts associated with flight test. To address this need, Systems Technology, Inc. is developing aFused Reality™ (FR) Flight system that allows a virtual environment to be integrated with thetest aircraft so that tasks such as aerial refueling, formation flying, or approach and landing canbe accomplished without additional aircraft resources or the risk of operating in close proximityto the ground or other aircraft. Furthermore, for the first time, the dynamic motions of thesimulated objects (e.g., refueling drogue or tanker) can be directly correlated with the responsesof the test aircraft. The FR Flight system will allow real-time observation of and manualinteraction with the cockpit environment that serves as a frame for the virtual out-the-windowscene. (PI: Ed Bachelder, edbach@systemstech.com)Aeroelastic Robustness ToolboxFlutter is a potentially explosive phenomenon that results from the simultaneous interaction ofaerodynamic, structural, and inertial forces. The nature of flutter mandates that flight testing becautious and conservative. In addition to the flutter instability, adverse aeroelastic phenomena

include limit cycle oscillations, buffeting, buzz, and undesirable gust response. The analyticalprediction of aeroelastic phenomena in the transonic regime has historically been troublesomeand requires high fidelity simulation models to obtain accurate predictions. The models are,however, computationally expensive. Traditional uncertainty analysis is therefore not oftenapplied to flutter prediction. This program is to develop computationally efficient methods thatreduce the existing computational time limitations of traditional uncertainty analysis. Buildingupon the successful Phase I demonstration, the coupling of Design of Experiments and ResponseSurface Methods and the application of robust stability techniques, namely μ-analysis, iscombined into a comprehensive software toolbox: STI-Aeroservoelastic Robustness Toolbox.STI-ART will have the flexibility to use computational unsteady aerodynamic and structuralfinite element models from a variety of sources, ranging from simple potential flow models (e.g.,doublet lattice methods) and linear structural models to solutions based on modeling of the full Navier Stokes equations and non-linear structural models with many elements. (PI: BrianDanowsky, bdanowsky@systemstech.com)Smart Adaptive Flight Effective Cue (SAFE-Cue)To enhance aviation safety, numerous adaptive control techniques have been developed tomaintain aircraft stability and performance in the presence of failures or damage. Flightevaluations of various adaptive controllers conducted by NASA and others have shown greatpromise. In some cases unfavorable pilot-vehicle interactions including pilot-induced oscillationshave occurred. Susceptibility to such interactions is more likely when the pilot interacts with ahighly nonlinear vehicle that may no longer have predictable response characteristics. Toalleviate these unfavorable interactions, Systems Technology, Inc. is developing the SmartAdaptive Flight Effective Cue or SAFE-Cue. This innovative system provides force feedback tothe pilot via an active control inceptor with corresponding command path gain adjustments. TheSAFE-Cue alerts the pilot that the adaptive control system is active, provides guidance via forcefeedback cues, and attenuates commands, thus ensuring pilot-vehicle system stability andperformance in the presence of damage or failures. Phase 2 will build upon a successful Phase 1demonstration wherein SAFE-Cue configurations eliminated pilot-vehicle system oscillationtendencies allowing the evaluation pilots to focus on the task rather than maintaining control. Inthis proposed program, a prototype SAFE-Cue will be developed and evaluated with exemplaradaptive controllers using the Calspan Learjet In-Flight Simulator. (PI: David Klyde,dklyde@systemstech.com)Modal Isolation and Damping for Adaptive AeroservoelasticSuppressionAdverse aeroservoelastic interaction is a problem on aircraft of all types causing repeatedloading, enhanced fatigue, undesirable oscillations and catastrophic flutter. Traditionally, tosuppress adverse aeroservoelastic interaction, notch and/or roll off filters are used in the primaryflight control system architecture. This solution has pitfalls; rigid body performance is degradeddue to resulting phase penalty and it is not robust to off nominal behavior. In Phase I, anapproach was developed that is entitled, Modal Isolation and Damping for AdaptiveAeroservoelastic Suppression (MIDAAS). This adaptive technique determines an optimal blendof multiple outputs that effectively isolates a problematic lightly damped mode andsimultaneously determines an optimal blend of multiple inputs to suppress the problematic modevia feedback. Adverse effects on aircraft rigid body performance are minimized, resulting invirtually no phase penalty. MIDAAS was validated against aeroservoelastic F/A-18C aircraftmodels with varying stores configurations and demonstrated very successful performance. In the

forthcoming Phase II program, a robust real-time adaptive aeroservoelastic suppression solutionwill be developed with a buildup approach that includes further MIDAAS enhancements,extensive validation studies utilizing a high-fidelity CFD-based aeroelastic model of the NASAX-53 aircraft, and extensive validation studies utilizing real-time pilot in the loop simulationcapability. (PI: Brian Danowsky, bdanowsky@systemstech.com)

National Research Council (NRC) Review of NASA Technology RoadmapsPresented by Phil Hattis

In response to a request from the NASA Office of the Chief Technologist, the NRC is performing a decadal-class study of NASA technology development roadmaps. The goals of the study are to review 14 NASA roadmaps addressing spaceflight capabilities, to identify important technology gaps in the roadmaps, and to prioritize applicable technology development investments over the next 10-20 years. Considerations in the technology development prioritization beyond relevance to NASA missions will include additional benefits to the nations and society. The process provides paths for public input to the process that include: A web site that provides a path to input comments on roadmap technologies and to identify important missing technologies; attendance at a series of workshops that will include presentations by leading experts on some of the technologies under review. A report on the findings from the review will be provided to NASA no later than January 2012.

Subcommittee A Abstracts

9.2 F-35B Jetborne Envelope ExpansionCAPT David “Dorkk” Silldorff, USNVehicle Systems Deputy IPT Lead

JSF Program Office

Joseph KrumenackerJSF Vehicle Control Integration Lead

NAVAIR Flight Controls BranchThis presentation provides an update on F-35B STOVL envelope expansion after about 16 months of STOVL mode (lift fan engaged) flight test. An overview of the F-35B test approach is provided, with an emphasis on jetborne envelope expansion. The presentation summarizes test progress in slow landings, vertical landings and slow takeoffs, since a previous F-35B ACGCS presentation (Meeting #105), and presents a recent typical test mission. A summary of the basic STOVL control philosophy and a translational rate-command (TRC) control philosophy for hovering flight are provided. The TRC philosophy was developed using combination of simulation assessment and flight test in the QinetiQ VAAC Harrier. The presentation provides a overview of some of the successes of jetborne flight test and the challenges that have created the need for some regression flight test. The presentation concludes with a summary of future plans for the F-35B aircraft and upcoming milestones.

9.3 FAST/Adaptive ControlCurt HansonNASA DFRC

A series of simple adaptive controllers with varying levels of complexity were designed, implemented and flight-tested on the NASA Full-Scale Advanced Systems Testbed (FAST) aircraft. Lessons learned from the development and flight testing are presented.

9.4 UAV Flying Characteristics Requirements SurveyDave Mitchell

Mitchell Aerospace ResearchThere is a need for a specification for the flying characteristics (or flight dynamics, or flying qualities) of UAVs. Acquisitions by US Government agencies have generally relied on flying qualities requirements and criteria taken without modification from piloted-aircraft specifications. NAVAIR recently funded a survey of selected designers and users of UAVs in or around Southern California. The survey found that most designers have internally derived performance criteria, some of which are based on manned requirements, but many of those criteria are very simple in format and do not necessarily address issues that are of interest to the Navy. Areas of interest for future research were identified as methods for verifying mission performance and system safety, especially in the presence of atmospheric turbulence. Existing turbulence/wind models are geared toward conventional airplanes, and new models are needed for small, high-aspect-ratio aircraft and aircraft with very low wing loadings.

Subcommittee B Abstracts

5.1 Kepler Attitude Control and Determination System Overview and Early Mission ExperiencesDustin Putnam, Ball Aerospace

The Kepler spacecraft was launched on March 7, 2009. Designed and built for NASA by Ball Aerospace & Technologies Corp., the Kepler mission uses the transit method to detect Earth-like exoplanets – approximately Earth-sized planets that are in the habitable zone of their stars.

Kepler, the largest telescope ever launched beyond Earth orbit, is in a heliocentric, Earth-trailing, drift-away orbit. It is a 3-axis stabilized, inertially-fixed pointer, using a combination of sun sensors, star trackers, inertial measurement units, and fine guidance sensors for attitude determination and reaction wheels and hydrazine thrusters for attitude and momentum control. This paper presents an overview of the Kepler mission, the ADCS design and some early mission experiences.

5.2 Overview of X-51A Design and Flight TestDr. Kevin G. Bowcutt, Boeing

The dream of hypersonic flight powered by air-breathing propulsion was born in the late 1950’s when the concept for a supersonic combustion ramjet (scramjet) engine was first conceived. In the 60 or so years since much work has been done to develop, test and prove the performance and operability of scramjet engines. Although there were two national programs in the 1960’s and 1980’s to design, build and fly a scramjet-powered aerospace plane (e.g., the NASP program from 1986-1994), neither culminated in flying a scramjet to prove that they worked as theorized. It wasn’t until this century that

scramjets were finally flown and proved to not only work, but to produce the level of thrust predicted by theory and measured in imperfect ground facilities.

The first flight test of an airframe-integrated scramjet occurred in 2004 when the NASA X-43A flew at nearly Mach 7 and then again at almost Mach 10 with a hydrogen-fueled scramjet. In this case the test vehicle was rocket-boosted to the test speed, it was heavier than the lift generated by its aerodynamic shape, it employed a heavy heat-sink scramjet, it was statically stable, and it produced only five to 10 seconds of scramjet data in flight before running out of hydrogen fuel.

The second flight test of a scramjet occurred in May, 2010 on the first USAF X-51A vehicle. The X-51 scramjet flight test program differs from X-43 in that the test vehicle is boosted to scramjet starting speed, accelerates to a cruise speed as high as Mach 6 using a flight-weight scramjet engine cooled by its own fuel, burns storable JP-7 hydrocarbon fuel, is highly unstable, and can fly for up to 300 seconds on scramjet power. Two to three additional X-51A flight tests are planned.

This presentation will summarize the design, development, and first flight test of the X-51A vehicle. A new design approach, multidisciplinary design optimization (MDO), was used to design the vehicle, which included stability and control directly in the process. Vehicle GNC for X-51A was very challenging, and these challenges and how they were tackled also will be discussed.

5.3 The TRACE Boogie: Flight Results for Minimum-Time Slew Maneuvers and Other Adventures in Optimal Control

Mark Karpenko, Andy Fleming, and I. Michael RossDepartment of Mechanical and Aerospace Engineering

Naval Postgraduate SchoolMonterey, CA 93943

Nazareth S. Bedrossian and Sagar A. BhattDraper LaboratoriesHouston, TX 77058

Osvaldo O. Cuevas, Mark A. Baugh, Ken L. Lebsock, Scott T. Snell, David A. Bradley, Steven W. Etchison, and Khary J. Johnson

NASA Goddard Space Flight CenterGreenbelt, MD 20771

During the month of August 2010, the TRACE spacecraft successfully executed a series of on-orbit minimum-time slew maneuvers. These minimum-time maneuvers were completed faster than the

equivalent slew about an eigenaxis. The non-eigenaxis slews were designed to allow the spacecraft to fully exploit the available control authority. In this context, the minimum-time slew maneuvers can be viewed as a space systems analog to Bernoulli’s famous brachistochrone problem – proving that the

fastest path is not always the shortest path. When a sequence of operationally-relevant, minimum-time slew maneuvers are strung together, the spacecraft performs an elegant dance as it follows each non-eigenaxis path. This departure from current operational practice was made possible through a number

of recent advances in optimal control theory and pseudospectral methods that make it possible to seamlessly incorporate practical constraints, such as nonlinear actuator limits and other existing control system characteristics, as part of the optimal control problem. Without this ability, it would be virtually impossible to assure that the minimum-time slews could be developed and successfully executed on-

orbit. This presentation will discuss the implementation and results of these historic maneuvers as well as some implications on operationalizing optimal maneuvering for current and future space systems.

The presentation will also discuss some additional applications of the new methodology in other areas including obstacle avoidance for air vehicles and cooperative motion planning for multiple robotic

manipulators operating in close proximity.

5.4 Low Noise MEMS Inertial Sensing in Space-Based Precision Pointing ApplicationsShan Mohiuddin, Peter Sherman, and John West

Draper LaboratoryDraper Laboratory’s DEXTRE Pointing Package (DPP) IMU program is a NASA/Goddard Space Flight Center supported effort to design a small, low-power precision pointing device for use on the International Space Station. The device, which includes a star camera and a Draper-designed MEMS inertial measurement unit, will support a number of tracking and proximity operations and will enable closed-loop control of the special purpose dexterous manipulator (SPDM) arm. The IMU and its supporting algorithms are designed specifically to provide the ability to gracefully navigate through star camera outages and to characterize the spacecraft’s vibration environment.

The SWaP constraints and the on orbit thermal environment present unique challenges for in-mission calibration and initialization of a MEMS inertial sensor. The sensors used here are a new generation of low noise instruments, but still carry significant turn-on errors and in-mission bias drift. Strategies for overcoming these challenges will be discussed, including algorithm development, sensor modeling, mission-specific CONOPS, and unique electronics and packaging design tuned to minimize the effects of thermal sensitivity. Simulation results will support this discussion.

Subcommittee C Abstracts

6.1 Research Activities for UAS National Airspace System IntegrationStan Pszczolkowski and Karen Buondonna

FAA Technical Center Federal Aviation Administration (FAA) experts at the William J. Hughes Technical Center, near Atlantic City, NJ, have stepped into the Unmanned Aircraft System (UAS) research and testing arena with a program that focuses on integrating UAS operations into the National Airspace System (NAS). A blend of laboratory modeling and simulation, and actual flight-testing are key components to these efforts.

The FAA’s main concern about UAS operations in the NAS is safety. It is critical that these aircraft neither endanger other users of the NAS nor compromise the safety of persons and property on the ground. The aviation community’s interest in using UAS for a broad range of purposes is increasing, making wider UAS access to the NAS a priority. The FAA is working closely with stakeholders in the UAS community to develop and validate appropriate operational procedures, regulatory standards and policies for routine NAS access.

The FAA is addressing these challenges through vigorous UAS research and testing programs managed by its Research and Technology Development Office. The objectives include the establishment of a baseline modeling and simulation capability, refine near-term operating concepts, explore NextGen technologies and concepts and support standards development, the safety case and RTCA SC-203 requirements validation. This is being accomplished through partnerships with UAS manufacturers, universities, government and industrial partners.

The FAA established the NextGen Integration and Evaluation Capability (NIEC) as part of the Technical Center’s large and comprehensive modeling and simulation, test and evaluation infrastructure. The NIEC includes three UAS ground control stations – Shadow, Predator and ScanEagle. UAS-related accomplishments and near-term plans using the NIEC include:

- Established Shadow and Predator performance characteristics in the NAS - Successfully coupled Shadow with flight management system for 4D trajectory operations- Demonstrated Predator with cockpit display of traffic information, voice over IP and ADS-B

capabilities- Conducted initial National Airspace System integrated simulations, more complex

simulations are planned- Investigated concept of operations for TCAS-equipped UAS- Assisted Marine Corps Cherry Point in certificate of authorization (COA) development

utilizing ground based sense and avoid- Assess the feasibility for multiple UASs in a civil/military environment at Victorville Class D

airspace (planned)

6.2 Verification & Validation Activities OverviewJon Hoffman

Air Vehicles DirectorateAir Force Research Laboratory

As the complexity of software continues to rise exponentially, developing new ways of certifying system safety is imperative. Mr. Hoffman from the Air Force Research Labs Air Vehicle Directorate (AFRL/RB) explains tools and techniques being explored in the areas of Verification and Validation (V&V) as they relate to the design and development of flight critical systems. He highlights current and near term activities as well as opportunities for upcoming collaboration.

6.4 A Criteria Standard for Conflict Resolution: A Vision for Guaranteeing the Safety of Self-Separation in NextGen

Dr. Ricky Butler,NASA Langley Research Center

Distributed approaches for conflict resolution rely on analyzing the behavior of each aircraft to ensure

that system-wide safety properties are maintained. This talk presents the criteria method, which increases the quality and efficiency of a safety assurance analysis for distributed air traffic concepts. The criteria standard is shown to provide two key safety properties: safe separation when only one aircraft maneuvers and safe separation when both aircraft maneuver at the same time. This approach is complemented with strong guarantees of correct operation through formal verification. To show that an algorithm is correct, i.e., that it always meets its specified safety property, one must only show that the algorithm satisfies the criteria. Once this is done, then the algorithm inherits the safety properties of the criteria. An important consequence of this approach is that there is no requirement that both aircraft execute the same conflict resolution algorithm. Therefore, the criteria approach allows different avionics manufacturers or even different airlines to use different algorithms, each optimized according to their own proprietary concerns.

Subcommittee D Abstracts

7.1 A Personal History from the Douglas Skyrocket to the Space ShuttleHerman A. Rediess, PhD

Herm Rediess began his Cooperative Work Study (Coop) Program at the NACA High Speed Flight Station when in his sophomore year at UC Berkeley in 1955 and returned, to what was then named the NASA Flight Research Center, after graduating. He conducted flight dynamics, controls and handling qualities research on several experimental and military aircraft. After receiving his doctorate from MIT, he rose to Director of Research. The last flight program at Dryden before transferring to NASA Headquarters in 1978 was the Space Shuttle Approach and Landing Test.

An extraordinary array of aircraft were tested during his tenure, including the Douglas Skyrocket D-558-2; X-series airplanes from X-1E through Lifting Bodies; most of the Century-series of fighters; numerous test-bed aircraft incorporating unique technology such as digital fly-by-wire system, integrated propulsion control system, supercritical wing; two variable stability aircraft (F-100 C and Lockheed JetStar); the Lunar Landing Research Vehicle; RPV research including Drone for Aerodynamics and Structural Testing (DAST), 3/8 Scaled F-15 spin vehicle, and HiMAT; and. several radio-controlled experimental aircraft now called mini RPVs.

This presentation provides an historical perspective of the flight research based on his experience from 1955 to 1978 with particular emphasis on flight dynamics, control and handling qualities research. It includes methods for estimating aircraft stability and control derivatives from flight test data (later known as parameter or systems identification), variable stability aircraft research, handling qualities, including pilot induced oscillations, integrated propulsion control systems, flight dynamics, digital fly-by-wire, and active controls technology.

7.2 Control of the Segmented Main Mirror for the Thirty Meter TelescopePeter M. Thompson, Chief Scientist

Systems Technology, Inc.The Thirty Meter Telescope Project is a collaboration of Caltech, University of California (UC) and the Association of Canadian Universities for Research in Astronomy (ACURA). The main mirror is composed of 492 hexagon segments. An overview is presented of the control issues for the main mirror, including requirements, pointing and tracking, shape control, phasing of the segments, and rejection of wind disturbance and vibration. A more detailed explanation will be presented of the shape control problem, including the selection of actuators and sensors, the inner servo loop, the outer global control loop, stability, and control structure interaction. The telescope will be located on Mauna Kea in Hawaii. First light for TMT with all segments aligned and phased, and with light through the Adaptive Optics Systems and onto the instruments is scheduled for 2019.

7.3 High Altitude Long Endurance AircraftEugene Lavretsky

The Boeing Company

This presentation is focused on Flight Simulation and Guidance, Navigation & Control (GN&C) technical challenges for Very Flexible Aerial (VFA) platforms. Motivation comes from the flight demonstrator programs such as HALE (Boeing Rapid Prototyping) and VULTURE (DARPA). We will review the stateof-the-art in simulation and flight control solutions for VFA vehicles, and propose path forward in the technology development to enable predictable flight performance for these emerging and challenging aerial platforms.

7.4 Apprenticeship Learning for High-Performance Helicopter FlightPieter Abbeel

Department of Electrical Engineering and Computer SciencesUniversity of California, Berkeley

For many robotic systems human operators still significantly outperform autonomous operation. "Apprenticeship Learning" is a new approach to high-performance robot control based on learning for control from ensembles of expert human demonstrations. In this talk I'll present the theory of our apprenticeship learning algorithms as well as experimental results in autonomous helicopter flight. Apprenticeship learning has enabled the most advanced helicopter aerobatics to-date, including maneuvers such as chaos, tic-tocs, and auto-rotation landings which only exceptional expert human pilots can fly.

Subcommittee E Abstracts

8.1 Aircraft propulsion control Technology development in the U.S.A Historical Perspective

Link C. JawScientific Monitoring, Inc., Scottsdale, Arizona

Sanjay GargNASA Glenn Research Center, Cleveland, Ohio

This paper presents a historical perspective of the advancement of control technologies for aircraft gas turbine engines. The paper primarily covers technology advances in the United States in the last 60 years (1940 ~ 2002) with an emphasis on the pioneering technologies that have been tested or implemented during this period. Since the first United States-built aircraft gas turbine engine was flown in 1942, engine control technology has evolved from a simple hydro-mechanical fuel metering valve to a full-authority digital electronic control system that is common to all modern aircraft propulsion systems. Using system complexity and capability as a measure, we can break the historical development of control systems down to four phases: 1) the start-up phase (1942 – 1949), 2) the growth phase (1950 – 1969), 3) the electronic phase (1970 – 1989), and 4) the integration phase (1990 – 2002). In each phase, the state-of-the-art control technology is described; the engines that have made historical landmarks, from the control and diagnostic standpoint, are identified. Then the historical perspective of the engine controls in the last 60 years is presented, in terms of control system complexity, number of sensors, number of lines of software (or embedded code), etc. The presentation has been updated to provide some perspective on propulsion control technology development since 2002.

8.2 Enabling Small Air Systems to Operate in Challenging Environments with Onboard Sensors and Processing

Eric N. JohnsonLockheed Martin Associate Professor of Avionics Integration

School of Aerospace Engineering, Georgia Institute of Technology

Typical current small unmanned aircraft systems require the human operator to do obstacle avoidance when vehicle is closer to obstacles than resolution of terrain database (or altitude measurement). Operations without GPS often imply increased human operator workload. To truly enable operations with in environments with these challenges with desired operator workload (i.e., no direct human operator, or human’s role is primarily to interpret ISR data) automatic obstacle avoidance and GPS denied operations are desired. In addition, one must accomplish this with purely onboard sensors and processing to achieve tolerance to communication failures. Automatic obstacle avoidance implies obstacle sensing. Small aircraft are particularly sensitive the weight and power penalties associated with active sensing systems. It also implies guidance for obstacle avoidance. GPS denied operations (including indoor) imply alternate sensor choices to bound inertial system drift, typically by sensing landmarks of opportunity in the environment. Estimation/navigation algorithms that these sensed feature are needed, such as the Simultaneous Localization and Mapping (SLAM) concept. This presentation includes sample vision-based navigation systems and an example of vision-based obstacle avoidance. For ranging sensor systems: a concept for a system that uses only ranging sensors is presented, as well as laser-aided inertial navigation and automatic nap-of-the-Earth helicopter flight using laser ranging sensors.

8.3 Credible Autocoding: Turning Proofs into CertificatesEric Feron

Dutton-Ducoffe Professor of Aerospace Software EngineeringGeorgia Institute of Technology

Advances in control systems technology, such as adaptive and nonlinear control, offers the potential for significant improvements of flight applications. However, this potential can be realized only if the software that implements these control laws can be easily verified and validated. In this talk we present a possible path from control system specifications to verified software. We discuss the concept of credible autocoding as a way to mechanize the implementation of this path. Finally we discuss the way forward from thereon.

8.4 Feature-based navigation of an Autonomous Underwater Vehicle (AUV)Christian Debrunner

Lockheed MartinUnder the Oil platform Inspection System (OPIS) program, a Lockheed Martin AUV, the MARLIN(TM), is being outfitted with a mission package which includes a 3D imaging sonar and processors in order to inspect and build 3D models of oil platforms, and to detect large scale damage to these platforms relative to a reference model. A key component of this model building and change detection functionality is a process by which sonar data is aligned to the reference model and the vehicle/sensor pose is recovered. An interesting by-product of this is the use of this recovered pose for feature based navigation. This paper presents a method to fuse the estimated pose from an inertial navigation system with the pose recovered from the alignment of sonar data with a reference model, and the use of this fused estimate in 3D model building and change detection, and to improve inertial navigation performance. While the technology is developed for an underwater platform inspection system, the methods have broader applicability. Simulation results are presented to demonstrate the performance of the feature-based navigation system.