In-Flight Simulation Control Law Design and Validation for RASCAL

In-flight simulation allows one aircraft to simulate the dynamic response of another aircraft. A control system designed to give RASCAL, a JUH-60A Black Hawk helicopter based at the U.S. Army Aeroflightdynamics Directorate in Moffett Field, CA, in-flight simulation capabilities has been designed, optimized and validated in this research. Classical explicit model following control laws with a frequency dependent feedback controller were used. The frequency dependent controller allows model following of the attitude in the short-term and the velocity in the long-term. Controller gains were optimized using a high-order, linearized model of UH-60 dynamics. Non-linear simulations of the control laws were performed in the RASCAL development facility, a hardware-in-the-loop simulator. Comparing quantitative performance metrics of the non-linear simulations with the predicted performance from the optimization with the linearized model ensured that the control system designed with the linearized model was valid in non-linear environments. Flight tests have been performed to validate the control laws quantitatively using frequency sweeps and qualitatively using ADS-33 mission task elements.