Robustness analysis for rotorcraft pilot coupling with helicopter flight control system in loop

Robustness analysis method is proposed for rotorcraft pilot coupling with helicopter flight control system in loop. Combining with the lateral identification model of BO-105 helicopter, McRuer's pilot model, and the designed stability augmentation system, frequency domain model is established for rotorcraft pilot coupling analysis. μ analysis method and performance specifications in ADS-33E are adopted to compare robust performances of the closed loop, furthermore, the worst case in uncertain model set is studied using robust performance detection. Moreover, the properties of root locus, damping ratio and mode frequency are studied from flight control system aspect. Feasible measures to improve the robust performance are discussed from the controller design consideration. Results show that the analysis method proposed can not only reveal the physical nature of coupling qualitatively, but also calculate the performances and boundaries quantitatively, which have theoretical reference significance in flight control system design.