Elastically Shaped Aircraft Concepts (ESAC) This research organized under the Fundamental Aeronautics Fixed Wing (FW) project aims to leverage increased flexibility of wing structures on transport aircraft for weight and drag reduction. Advanced controls are being developed to reduce trim drag through wing shaping at cruise while maintaining aeroelastic stability. Flight control architectures are being developed for active flutter suppression.
POC: Nhan Nguyen
Loss-of-Control Prediction and Cueing Flying near the edge of a safe operating envelope is an inherently difficult proposition. Edge of the envelope here implies that small changes or disturbances in system state or system dynamics can take the system out of the safe envelope in a short time and could result in loss-of-control events. Our research examines approaches to predicting loss-of-control safety margins as the aircraft gets closer to the edge of the safe operating envelope with the goal of providing the pilot a decision aid focused on maintaining the pilot's control action within predicted loss-of-control boundaries. Our predictive architecture combines quantitative loss-of-control boundaries, an adaptive prediction method to estimate in real-time Markov model parameters and associated stability margins, and a real-time data-based predictive control margins estimation algorithm. The combined architecture is applied to linear and nonlinear generic transport aircraft models to illustrate the features of the architecture.
POC: Kalmanje Krishnakumar
Synchronized Position Hold, Engage, Reorient Experimental Satellites (SPHERES) SPHERES are bowling ball-sized spherical satellites with power, propulsion, computers, and navigation that can be used for inspections, maintenance, spacecraft assembly, and other intravehicular operations. The International Space Station (ISS) has been using three of them to conduct science and test a diverse array of hardware and software for more than a decade.
POC: Jonathan Barlow
Intelligent Flight Planning and Guidance
The goal of this project is to investigate intelligent flight planning and guidance concepts that can assist pilots in achieving a safe runway landing during off-nominal conditions. To achieve this, foundational technologies will need to be developed.
These technologies will be integrated together, along with the adaptive control systems, and utilize available vehicle health information in order to provide significantly increased levels of safety when operating under off- nominal conditions.
POC: John Kaneshige
Data-based Predictive Control This research will focus on arriving at an advanced control architecture that can be applied to control of non-conventional vehicle regimes with the specific focus on controlling for robust and optimal performance of CESTOL vehicles during transitions between low and high speeds. Our research incorporates a novel blend of intelligent flight-propulsion control and intelligent control allocation, with the focus specifically on developing a suitable data- based predictive performance seeking control algorithm using theoretically grounded approaches that rely only on input-output data and an assumed bandwidth of the system. A successful research, development, and test will necessitate (a) a novel intelligent controller that is appropriate for NextGen CESTOL, or similarly complex, aircraft; (b) a significant increase in performance over traditional approaches while maintaining stability in the classical sense; and (c) a single controller functional across the entire envelope of aircraft operation.
Evolvable Systems The Evolvable Systems Group investigates computer algorithms that automate the design and optimization of complex engineering systems for current and future NASA missions. Our overall goal is to dramatically increase mission reliability and science return through development and application of adaptive and evolutionary algorithms. Our current research involves writing computer algorithms that make reconfigurable electronics more reliable, design high-performance antennas and analog circuits, improve satellite scheduling, discover new robotic structures and controllers, improve multiobjective optimization via artificial coevolution, and optimize MEMS devices.
Hardware Test Bed and Data Acquisition System for Wind Turbine Adaptive Control Algorithms (+More) NASA is using its expertise in the areas of intelligent controls and systems health management to help broaden our nation’s renewable energy portfolio. Wind turbine manufacturers and operators continually search for ways to maximize energy capture and production, as well as minimize turbine down-time and maintenance costs. Low frequency, time-varying structural modes can interfere with the control systems of utility scale wind turbines resulting in increased fatigue loads on the tower and blades. Disturbance accommodating adaptive residual mode filter control algorithms that allow wind turbines to operate optimally in the presence of these modes have been developed and tested in computer simulation by researchers at NASA Ames Research Center.
Hypersonics Guidance and Control The research focus of the Hypersonics G&C project are:
(1) Development of models and associated control algorithms, analysis tools and design methodologies that permit the design of Highly Reliable Reusable Launch Systems (HRRLS) which offer robust dynamic performance in the presence of significant uncertainty by exploiting real-time measurements and available control actuators.
(2) Integration of control relevancy into the overall vehicle conceptualization, sizing, and design process. This will be done by incorporating control-relevant dynamical objectives (e.g. performance, robustness)
Integrated Resilient Aircraft Control (IRAC)
The Integrated Resilient Aircraft Control (IRAC) Project conducts research to advance the state of aircraft flight control to provide onboard control resilience for ensuring safe flight in the presence of adverse conditions. The goal of the IRAC project is to arrive at a set of validated multidisciplinary integrated aircraft control design tools and techniques for enabling safe flight in the presence of adverse conditions (e.g., faults, damage and/or upsets). One objective towards this goal is to advance the state-of-the-art of adaptive controls as a design option to provide enhanced stability and maneuverability margins for safe landing. Adverse events include loss of control caused by environmental factors, actuator and sensor faults or failures, and will expand toward more complicated damage conditions.
The application focus of this technology is for current and next generation subsonic civil transports. However, a majority of the challenges addressed by the IRAC project are general in nature, and therefore, the solutions will apply to a large class of aviation vehicles. Integrated adaptive controls require improved models that include system interactions between structures, flight controls and/ or the propulsion system. These modeling efforts will strive to achieve dynamically representative interactions to allow for control law design and evaluation. An example is the need for improved departure and post-departure dynamic modeling of a civil transport class aircraft. Details of the dynamics involved in loss of control are required to better understand how the adaptive system can best regain control without further exacerbating the situation. Another example includes the enhancements to propulsion modeling for situations requiring effective integrated flight and propulsion control.
Successful transition of foundational research into national airspace system deployment relies greatly on the ability to verify and validate integrated adaptive control technologies. Efforts for validation will utilize simulators, wind tunnels, and sub- and full-scale flight test vehicles. Research and technologies from other Aeronautics projects across NASA will be leveraged where found to be beneficial to the IRAC project.
POC: Kalmanje Krishnakumar
Lunar CRater Observation and Sensing Satellite (LCROSS)
The Mission Objectives of the Lunar Crater Observation and Sensing Satellite (LCROSS) include confirming the presence or absence of water ice in a permanently shadowed crater at the Moon’s South Pole. The identification of water is very important to the future of human activities on the Moon. LCROSS will excavate the permanently dark floor of one of the Moon’s polar craters with two heavy impactors early in 2009 to test the theory that ancient ice lies buried there. The impact will eject material from the crater’s surface to create a plume that specialized instruments will be able to analyze for the presence of water (ice and vapor), hydrocarbons and hydrated materials.
The focus within ACES is the research on technologies for modular, reconfigurable subsystems that can be used to support future mission architectures.
Polymorphic Control Systems Project
The maturation of wireless and distributed technologies, such as distributed sensor networks and low-cost secure wireless communication, is resulting in the emerging ubiquity of wireless technologies in a large number of domains. These recent advances are opening the door to new methods of control reconfiguration utilizing remote avionics, actuation, and sensing. Plug-and-play concepts describe dynamic network topologies, where information-sharing networks are established and reconfigured on-the-fly as a function of the resources available at any given time.
These concepts could be formulated to establish dynamic distributed avionics networks as the backbone for communications in a single vehicle system or a system of systems that would allow for markedly enhanced performance, resilience, and fault-tolerance. These networks would allow for instance the instantaneous restructuring of coordinated control systems in a group of vehicles utilizing delocalized sensors, actuators, and controllers to establish highly unusual control configurations, providing fault-tolerance to a wider class of vehicle system failures that previous approaches were ill-equipped to handle. Control systems in these dynamic networks would be capable of instantaneous polymorphic change – instantaneous and fundamental restructuring of the controller form and function. The Polymorphic Control Systems project seeks to formulate these concepts and synthesize approaches to control system development towards the goal of drastically increased performance, resilience, and fault-tolerance.
Small Spacecraft Guidance, Navigation, and Control in Support
of The Lunar Exploration Program
ACES is playing the lead role in developing the software and avionics for the Modular Common Spacecraft Bus (MCSB). In support of the Science Mission Directorate, the goal of this spacecraft is to lower the cost and schedule for deploying science instruments into space. The spacecraft uses a modular approach for subsystems such that it can be reconfigured to work in a wide range of flight applications. The first mission for the Common Bus spacecraft is the recently announced “Lunar Atmosphere and Dust Environment Experiment (LADEE)”. LADEE will launch in 2011, and will collect science data regarding the lunar residual atmosphere by flying in a lunar orbit for approximately 90 days.
To support the MCSB goals, the ACES group is putting together an infrastructure for the rapid development and deployment of small spacecraft by leveraging DoD experience and technologies in missile defense and anti-satellite interceptors. Primarily, this infrastructure is based on a technique known as model based software development. In this technique, models of the spacecraft and flight software are developed in a dynamics modeling package, such as Mathworks’ Simulink. After the model is shown to work as desired in this simulation framework, software is automatically generated from the models. The generated software is then tested in real time Processor-in-the-Loop and Hardware-in-the-Loop testbeds. These techniques are applied early and often in the development process, iteratively increasing the capabilities of the software and the fidelity of the vehicle models.
To demonstrate this capability, a prototype of the MCSB was flown recently in a number of short hover tests. The prototype utilized a cold gas propulsion system to fly stable, untethered for approximately six seconds, repeatedly landing within two meters of a desired final position. The system used flight-like hardware for the avionics and attitude sensing. The flight software included Command and Data Handling, Vehicle Health Management, and Guidance, Navigation, and Control software. Commercially available ground data systems software was used to monitor and command the spacecraft. Roughly 85% of the flight software was automatically generated from models, proving the validity and value of these techniques. For more information on the MCSB testing including videos visit: Wired Science Blog - Meet the Spacecraft That Could Save NASA a Fortune
POC: Howard Cannon
Deputy Group Lead