Human-In-The-Loop stability analysis: pure gain human model
For the tasks that require very accurate control commands, such as aerial refueling or aircraft landing, pilots are shown to produce control commands resembling the output of a pure gain controller. Therefore, analyzing the stability of the uncertain nonlinear closed loop system with a pure gain pilot model should be done at first.
Human-In-The-Loop stability analysis: lag filter
Another commonly employed model to represent the human operator’s inability to respond to high-frequency inputs is the lag filter. Our second analysis shows the stability properties of the human-in-the-loop control system where a lag filter operator model is utilized.
Shahab Tohidi, and Yildiray Yildiz, “Adaptive Control Allocation: A Human-In-The-Loop Stability Analysis,” International Federation of Automatic Control (IFAC), 2020.