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| Meeting | ACGS Committee Meeting 107 - Boulder - March 2011 | | Agenda Location | 4 GENERAL COMMITTEE TECHNICAL SESSION
4.2 Research Institutions, Industry and University Reports
4.2.2 Research Institutions and Companies
4.2.2.5 Systems Technology, Inc. | | Title | Systems Technology, Inc. | | Presenter | David Klyde | | Available Downloads* | presentation | | *Downloads are available to members who are logged in and either Active or attended this meeting. | | Abstract | Recent Activities at Systems Technology, Inc.
David Klyde
dklyde@systemstech.com
Fused Reality Flight for Enhanced Flight Test Capabilities
In terms of relevancy to piloted evaluation, there remains no substitute for actual flight tests even when considering the fidelity and effectiveness of modern ground-based simulators. In addition to real world cueing (vestibular, visual, aural, environmental, etc.), flight test provides subtle but key intangibles that cannot be duplicated in a ground-based simulator. There is, however, a cost to be paid for the benefits of flight in terms of budget, mission complexity, and safety including the need for ground and control room personnel, additional aircraft, etc. New technologies and test procedures are therefore needed to maximize the investments and reduce some of the related costs associated with flight test. To address this need, Systems Technology, Inc. is developing a Fused Reality™ (FR) Flight system that allows a virtual environment to be integrated with the test aircraft so that tasks such as aerial refueling, formation flying, or approach and landing can be accomplished without additional aircraft resources or the risk of operating in close proximity to the ground or other aircraft. Furthermore, for the first time, the dynamic motions of the simulated objects (e.g., refueling drogue or tanker) can be directly correlated with the responses of the test aircraft. The FR Flight system will allow real-time observation of and manual interaction with the cockpit environment that serves as a frame for the virtual out-the-window scene. (PI: Ed Bachelder, edbach@systemstech.com)
Aeroelastic Robustness Toolbox
Flutter is a potentially explosive phenomenon that results from the simultaneous interaction of aerodynamic, structural, and inertial forces. The nature of flutter mandates that flight testing be cautious and conservative. In addition to the flutter instability, adverse aeroelastic phenomena include limit cycle oscillations, buffeting, buzz, and undesirable gust response. The analytical prediction of aeroelastic phenomena in the transonic regime has historically been troublesome and requires high fidelity simulation models to obtain accurate predictions. The models are, however, computationally expensive. Traditional uncertainty analysis is therefore not often applied to flutter prediction. This program is to develop computationally efficient methods that reduce the existing computational time limitations of traditional uncertainty analysis. Building upon the successful Phase I demonstration, the coupling of Design of Experiments and Response Surface Methods and the application of robust stability techniques, namely -analysis, is combined into a comprehensive software toolbox: STI-Aeroservoelastic Robustness Toolbox. STI-ART will have the flexibility to use computational unsteady aerodynamic and structural finite 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: Brian Danowsky, bdanowsky@systemstech.com)
Smart Adaptive Flight Effective Cue (SAFE-Cue)
To enhance aviation safety, numerous adaptive control techniques have been developed to maintain aircraft stability and performance in the presence of failures or damage. Flight evaluations of various adaptive controllers conducted by NASA and others have shown great promise. In some cases unfavorable pilot-vehicle interactions including pilot-induced oscillations have occurred. Susceptibility to such interactions is more likely when the pilot interacts with a highly nonlinear vehicle that may no longer have predictable response characteristics. To alleviate these unfavorable interactions, Systems Technology, Inc. is developing the Smart Adaptive Flight Effective Cue or SAFE-Cue. This innovative system provides force feedback to the pilot via an active control inceptor with corresponding command path gain adjustments. The SAFE-Cue alerts the pilot that the adaptive control system is active, provides guidance via force feedback cues, and attenuates commands, thus ensuring pilot-vehicle system stability and performance in the presence of damage or failures. Phase 2 will build upon a successful Phase 1 demonstration wherein SAFE-Cue configurations eliminated pilot-vehicle system oscillation tendencies allowing the evaluation pilots to focus on the task rather than maintaining control. In this proposed program, a prototype SAFE-Cue will be developed and evaluated with exemplar adaptive controllers using the Calspan Learjet In-Flight Simulator. (PI: David Klyde, dklyde@systemstech.com)
Modal Isolation and Damping for Adaptive AeroservoelasticSuppression
Adverse aeroservoelastic interaction is a problem on aircraft of all types causing repeated loading, enhanced fatigue, undesirable oscillations and catastrophic flutter. Traditionally, to suppress adverse aeroservoelastic interaction, notch and/or roll off filters are used in the primary flight control system architecture. This solution has pitfalls; rigid body performance is degraded due to resulting phase penalty and it is not robust to off nominal behavior. In Phase I, an approach was developed that is entitled, Modal Isolation and Damping for Adaptive Aeroservoelastic Suppression (MIDAAS). This adaptive technique determines an optimal blend of multiple outputs that effectively isolates a problematic lightly damped mode and simultaneously determines an optimal blend of multiple inputs to suppress the problematic mode via feedback. Adverse effects on aircraft rigid body performance are minimized, resulting in virtually no phase penalty. MIDAAS was validated against aeroservoelastic F/A-18C aircraft models with varying stores configurations and demonstrated very successful performance. In the forthcoming Phase II program, a robust real-time adaptive aeroservoelastic suppression solution will be developed with a buildup approach that includes further MIDAAS enhancements, extensive validation studies utilizing a high-fidelity CFD-based aeroelastic model of the NASA X-53 aircraft, and extensive validation studies utilizing real-time pilot in the loop simulation capability. (PI: Brian Danowsky, bdanowsky@systemstech.com) |
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