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Meeting	ACGS Committee Meeting 105 - Lake Tahoe - March 2010
Agenda Location	4 GENERAL COMMITTEE TECHNICAL SESSION 4.2 Research Institutions, Industry and University Reports 4.2.2 Research Institutions and Companies 4.2.2.1 Systems Technologies Inc.
Title	Systems Technologies Inc.
Presenter	David Klyde
Available Downloads*	presentation
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Abstract	This presentation summarizes five projects that have recently started at STI. Abstracts for the projects are provided below. Optimal Autorotative Profiles Using Active Inceptor Cueing Rotorcraft autorotation is a particularly challenging maneuver whose training demands are inadequately addressed in military or civilian aviation. Tactile safeguards may be one of the most effective means for protecting against control misapplication due to training gaps and negative training. In response STI is developing the Optimal Autorotation Cueing System (OACS). OACS takes its guidance from optimal aircraft trajectories and control commands computed with the direct-collocation optimization method, solved using a commercially available nonlinear programming problem solver. In Phase I an active cyclic will be used to demonstrate active inceptor feasibility during autorotation, while the collective inputs generated by the optimizer are issued directly to the helicopter simulator. OACS will offer both envelope protection as well as guidance control via the active cyclic. Cueing control law configurations will be demonstrated using human-in-the-loop flight simulation at the conclusion of the project. Flying Qualities Metrics and Design Guidelines for Modern Transport Aircraft Current and planned transport aircraft designs are making more use of fly-by-wire technology, allowing an unprecedented design space for control laws, including adaptive control concepts, and resulting response-types. The resulting higher order responses do not lend themselves well to the modal flying qualities requirements that were developed more than four decades ago for conventional aircraft response-types. Furthermore, this expanded design space also makes it possible to implement flight control systems that can lead to unintended degraded flying qualities and undesirable pilot-vehicle interactions. The transport aircraft control system design engineer needs to have tools in the form of modern flying qualities metrics to help determine the permissible thresholds of control while still suppressing undesirable dynamic esponses. To address this need a Matlab-based toolbox that will feature modern requirements validated from a new flight test database, built-in data reduction tools, and expert system guidance will be developed. In Phase 1 critical requirements areas will be identified and explored via piloted simulation to demonstrate feasibility of the proposed approach. Candidate requirements will then be evaluated via a formal flight test program to be conducted in Phase 2 with the Calspan Learjet in-flight simulator. Smart Adaptive Flight Effective Cue (SAFE-Cue) As a means to enhance aviation safety, numerous adaptive control techniques have been developed to maintain aircraft stability and safety of flight in the presence of failures or damage. The techniques apply a wide array of adaptations from simple gain scheduling to on-line learning algorithms. While the ready availability of low cost, reduced scale UAV systems have allowed for many successful flight test demonstrations, applications to piloted aircraft have been more limited. Flight evaluations of various adaptive control applications conducted by NASA and others have shown great promise. In some cases; however, 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, the Smart Adaptive Flight Effective Cue or SAFE-Cue will provide cues to the pilot via an active control inceptor with corresponding command path gain adjustments. The SAFE-Cue will alert the pilot that the adaptive control system is active and provide guidance through a force feedback cue and command attenuation via a command path gain adjustment as a means to retain pilot-vehicle system stability and performance. Real-Time Methods for Adaptive Suppression of Adverse Aeroservoelastic Dynamics Adverse aeroservoelastic (ASE) interaction is a problem on new and existing aircraft of all types causing repeated loading, enhanced fatigue and undesirable oscillations for pilots. Traditionally, to suppress adverse ASE interaction, notch and/or roll off filters have been utilized in the flight control system architecture to effectively “cancel out” problematic frequencies that will potentially excite the ASE dynamics. This solution has pitfalls; rigid body performance is degraded due to the resulting phase penalty and the filter is not robust to unexpected or unmodeled off nominal behavior. STI will develop an adaptive approach, which is leveraged by the adaptive Higher Harmonic Control (HHC) algorithm for high frequency disturbance rejection. This adaptive approach is robust to system variations, minimizes lower frequency phase penalty, and has been utilized for similar dynamic systems with supporting experimental validation. Development of the adaptive HHC algorithm for ASE suppression will be accomplished utilizing a high fidelity model of a representative high-speed fighter aircraft that is capable of parameter variation consisting of flight condition changes, configuration changes (stores configurations) as well as damage and failures. Validation of the proposed approach will be accomplished via simulation with representative parameter variations. Validation via real-time piloted simulations is proposed for future studies. Advanced Turboshaft Engine/Drivetrain Modeling Technique for Real Time Rotorcraft Simulation Simulation is an indispensable tool in the development and evolution of modern rotorcraft designs and flight training activities, with the gas turbine engine being a particularly demanding component to simulate. To provide for enhanced simulation fidelity regarding this critical component, the Army has identified a need for a generic turboshaft engine/drivetrain model. Such a model will be used to support real-time rotorcraft flight simulation activities that can be initiated early in the design cycle. To meet this need, a physics-based model of generic architecture that can be readily integrated into industry standard simulations will be created. When fully developed, the model will be a gas turbine engine model that is a careful blend of performance requirements, physics, and abstraction. The model will feature a virtual test stand through which the model can be executed as a stand alone application to ease checkout and parameter tuning functions. A beta version will be created in Phase 1 and integrated into a realtime rotorcraft simulator to demonstrate feasibility of the approach via a limited piloted simulation of start up and low speed characteristics.