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Autonomous Control Modes and Optimized Path Guidance for Shipboard Landing in High Sea States

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Technical Report,10 Jan 2015,09 Apr 2016

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The Pennsylvania State University University Park United States

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This project is performed under the Office of Naval Research program on Basic and Applied Research in Sea- Based Aviation ONR BAA12-SN-0028. This project addresses the Sea Based Aviation SBA initiative in Advanced Handling Qualities for Rotorcraft. Landing a rotorcraft on a moving ship deck and under the influence of the unsteady ship airwake is extremely challenging. In high sea states, gusty conditions, and a degraded visual environment, workload during the landing task begins to approach the limits of a human pilots capability. It is a similarly demanding task for shipboard launch and recovery of a VTOL UAV. There is a clear need for additional levels of stability and control augmentation and, ultimately, fully autonomous landing possibly with manual pilot control as a back-up mode for piloted flight. There is also a clear need for advanced flight controls to expand the operational conditions in which safe landings for both manned and unmanned rotorcraft can be performed. For piloted rotorcraft, the current piloting strategies do not even make use of the available couplers and autopilot systemsduring landing operations. One of the reasons is that, as the deck pitches and rolls in high sea states, the pilot must maneuver aggressively to perform a station-keeping task over the landing spot. The required maneuvering can easily saturate an autopilot that uses a rate limited trim system. For fly-by-wire aircraft, there is evidence that the pilot would simply over-compensate and negate the effectiveness of a translation rate commandposition hold control mode. In addition, the pilots can easily over-torque the rotorcraft, especially if they attempt to match the vertical motion of the deck. This project seeks to develop advanced control law frameworks and design methodologies to provide autonomous landing or, alternatively, a high level of control augmentation for pilot-in-the-loop landings.

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