The Analysis and Research on the Effects Caused by the Pilot Model Parameters to the Pilot Induced Oscillation and Feasible Countermeasure of the Helicopter

The closed-loop stability analysis method on the pilot model parameters is proposed for pilot induced oscillation problem caused by the pilot in the closed loop of the helicopter. The control characteristics of the helicopter pilot coupling closed-loop system are studied with different pilot model parameters. Then feasible countermeasures to improve the stability, robustness as well as the flight quality of the helicopter in order to restrain the PIO are discussed from the perspectives of the pilot's manipulation and the flight control system. Results show that the increase of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{k}_{\boldsymbol{pl}}, \boldsymbol{T}_{\boldsymbol{L}}, \boldsymbol{\tau}_{\boldsymbol{pl}}$</tex> and the decrease of the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{T}_{\boldsymbol{l}}$</tex> lead to larger probability of the PIO and more unstable and unrobust helicopter pilot coupling closed-loop system. The pilot should be well-trained and the manipulation should be moderate, the parameters of the flight control system should be adjusted properly in accordance with the demands of the mission in order to enhance the flight stability, robustness and quality, the improved performances of the helicopter pilot coupling closed-loop system are desirable. The analysis methods proposed in this paper reveal the physical nature of the research issue qualitatively and quantitatively, which is theoretically and practically referential to the helicopter flight.