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Sunnyvale, CA, United States

Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase II | Award Amount: 779.98K | Year: 2012

Flight simulation provides a cost effective tool for testing aircraft systems. Testing avionics systems across a particular flight profile requires driving the simulation through the flight profile to generate the required simulated sensor data. Testing avionics systems with a human pilot is costly and it cannot provide precise repeatability, which is essential to evaluating the effect of mission parameters on aircraft survivability. However, a"virtual pilot"is capable of generating a repeatable control, which guarantees an identical flight every time. Development of a virtual pilot that can address a range of maneuvers and which can be adapted to various aircraft configurations is a demanding task. Most current methods are not feasible for use by application Test Engineers since those methods require manual tuning of the virtual pilot for each configuration and for each maneuver. Under this SBIR, ART proposes to develop a virtual pilot control generation tool that can accomplish the task effectively. The problems of accuracy, robustness, and efficiency will be addressed using the advanced inverse simulation technique, the mathematical optimization method, a feedback compensator, and parallel computing. A graphical user interface will be developed in order to facilitate the tool usage. The innovation involved is the integration of the diverse technologies of rotorcraft modeling, inverse simulation, and optimization into a unified tool that is efficient and effective in providing a repeatable control history to drive nonlinear rotorcraft models through user defined flight profiles.

Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2015

Most existing finite state inflow models that are widely used in flight dynamics simulation are limited to only modeling single main rotor helicopters. Modern advanced rotorcraft configurations usually involve multiple main rotors (e.g., co-axial, tilt-rotor, etc.), ducted fans, auxiliary wings, etc.. Advances in rotor inflow modeling are needed to extend the current modeling capability to provide effective support for the design and development of advanced rotorcraft configurations. An innovative approach is proposed to develop an accurate formulation of a finite state rotor inflow solution for advanced rotorcraft configurations that is well suited for flight dynamics and control applications. The innovative methodology and implementation algorithms will be thoroughly described and tested. The feasibility of the proposed solution will be demonstrated and validated with examples in both the time and frequency domains.

Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase I | Award Amount: 79.99K | Year: 2015

Towing of a Magnetic Anomaly Detection (MAD) system is an important aspect of rotorcraft maritime operation in support of Anti-Submarine Warfare (ASW). The vibratory rotary wing platform combined with the long and flexible towing cable, the low mass ratio of the towed body to the total mass (the sum of the tow body and the towing aircraft), and the rotor downwash impingement on the towed body during deployment presents a challenging task for integration of a modern towed MAD system on USN airborne ASW platforms. Phase I of the proposed research emphasizes towing simulation methodology research and development. Phase I will also carry out a full flight simulation with a towed body to demonstrate the feasibility of the proposed simulation method. Overall, Phase I will accomplish (1) the development of a high fidelity aircraft simulation model for accurately capturing both the steady state performance and the vibratory characteristics of the towing operation; (2) the development of a state-of-the-art model for the interference of the towing aircraft rotor wake on the towed body; (3) the development of high fidelity dynamics and aerodynamics modelling of the towing system including the towing cable, the towed body, and the cable attachment device; (4) the performance of a full flight simulation with the integrated towing aircraft and towing system; (5) the performance of initial parametric studies to investigate the towed body aerodynamic and dynamic characteristics including the effects of body geometry, size, mass/inertia/CG, aerodynamic stabilizing surfaces, etc.

Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2016

Helicopter buffeting is an aeroelastic problem, with mutually interacting airloads and structural motions from the rotor, hub, fuselage, and empennage. Buffeting is amenable to the state-of-the-art analysis technology and addressing it is long overdue. Computational Fluid Dynamics (CFD) provides the highest fidelity for the fluid physics while Computational Structural Dynamics (CSD) provides accurate elastic structure modeling. Combined, CFD/CSD coupled analysis is essential to representing the mutually dependent aeroelastic interactions associated with buffeting. However, current coupling implementations are limited to rotors and wings, while the fuselage and empennage structures critical to the prediction of buffeting are rigidly modeled. An opportunity exists to address this problem by expanding CFD/CSD coupled analysis technology to include the aeroelastic coupling of fuselage and empennage. This effort leverages existing technology for CSD by utilizing the Rotorcraft Comprehensive Analysis System (RCAS) and CFD by utilizing OVERFLOW and Create-AV Helios to focus development on the fluid structure interface (FSI). The main requirements of which are the accurate transfer of deformations to CFD and energy conservation during the application of aerodynamic forces to CSD. Although this development targets interfacing CFD with RCAS, the developed FSI will be general and made available for integration into other structural dynamics programs.

Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase II | Award Amount: 729.90K | Year: 2011

Modeling engine and drivetrain (i.e., propulsion system) dynamics and control is a vital part of modern rotorcraft simulation as they are closely coupled with the rotor dynamics and impact the aircraft performance and transient response. The current engine modeling method for real time rotorcraft simulation relies heavily on empirical estimation and, hence, is severely limited by the availability of the data and also suffers from an inaccuracy in predicting the engine/drivetrain transient states. The proposed SBIR is dedicated to the development of a first principle based engine and drivetrain dynamics and control modeling method that will reflect rotorcraft propulsion system physics and provide an accurate simulation solution. The proposed solution will be rigorously formulated and applicable for generic turboshaft engine/drivetrain modeling. The formulation will consider the entire engine operational range including start-up, idle, started, and shut-down. The simulation implementation will also address the interaction with the engine fuel control dynamics and the drivetrain/rotor coupling for a fully integrated solution. The engine dynamic model will be developed in modular form so that it can be easily integrated with rotorcraft flight simulation programs or used as a standalone model as a plug-in in any analysis program in support of engine dynamics and engine control analysis. The physics-based solution thus developed will be tested and evaluated in an industry standard rotorcraft modeling and simulation program to validate the methodology in support of rotorcraft analysis and flight simulation.

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