System identification methods have played an essential role in the research and industry projects at the Institute of Flight System Dynamics of the Technical University of Munich. Besides the application of the established system identification approaches to multiple aircraft, novel methods have been developed at the institute to deal with the challenges associated with fixed- and rotary-wing aircraft system identification in the time and frequency domains. This paper provides an overview of these new developments, as well as practical application examples from the past and ongoing projects at the institute. After a brief introduction to the work at the institute, the paper describes the new advancements in the fields of time domain system identification and optimal input design by introducing optimal control methods. It continues with an alternative problem formulation for applying frequency domain system identification and parameter estimation methods to a novel flight control design and tuning approach. Additional topics from the past and ongoing research at the institute such as novel methods and practical findings in rotorcraft system identification and flight path reconstruction for different applications will be discussed and referenced.

View Video Presentation: https://doi.org/10.2514/6.2022-2170.vid A flight test campaign is being prepared for system identification on a general aviation aircraft. The goal is to analyze the effectivity and efficiency of different maneuvers, injected in a closed-loop environment with different controller settings. In a first step, the information content of the planned flight test campaign is evaluated, for the open-loop injection of the system identification maneuvers. Furthermore, the effects of the activation of the feedback controller with different gains during the maneuvers is studied. Preliminary flight tests have been performed on a small drone to validate the simulation based analysis.

An electromechanical actuator system was used on a general aviation aircraft to automatically execute programmed test inputs for system identification and parameter estimation. The flight test campaign consisted of approximately 10 flight hours with over 250 carefully designed dynamic test inputs, including multisteps, frequency sweeps, phase-optimized orthogonal multisines, and the optimal inputs for parameter estimation. This paper describes the actuator system retrofitted to the REMOS GX aircraft and the software developed for automatic maneuver injection. The design of the flight test maneuvers is discussed while considering the characteristics and the limits of the onboard actuator system. The initial parameter estimation results are used to evaluate the effectiveness of the applied methods, which is a first for a light sport aircraft. The lessons learned and the advantages of such a system with respect to manual (piloted) flight testing will be described, as will recommendations for future applications of electromechanical actuators to aircraft of this weight class.