As the complexity of flight tasks increases , the linearized equation based on the small disturbance theory is no longer adequate for the design of control systems , and the necessity of exploring a nonlinear approach seems increasingly obvious 隨著飛機飛行任務不斷趨向復雜化,基于小擾動線性化方程的線性系統設計方法已經難以滿足現代飛機飛控系統的設計要求。這就迫使我們研究飛機的非線性控制律的設計方法。
As the complexity of flight tasks increases , the linearized equation based on the small disturbance theory is no longer adequate for the design of control systems , and the necessity of exploring a nonlinear approach seems increasingly obvious 隨著飛機飛行任務不斷趨向復雜化,飛機的動態模型具有顯著的非線性,基于小擾動線性化方程的線性系統設計方法已經難以滿足系統設計的要求。這就迫使我們研究飛機的非線性設計方法。
In chapter 3 , the non - linear equation was linearized with the jacobi matrix , and then the linearized equation was transformed into fixed frame to analyze the stability problem with eigenvalue method ( on - ground or hovering ) or floquet theory ( forward flight ) . meanwhile , the equation was perturbed by sweep frequency excitation from steady state to get transit decay of lag response which was then transformed into fixed frame with a numerical fourier coordination transformation ( fct ) . the fixed frame response along with the body response was analyzed via an fft to determine modal frequencies 然后,在穩態響應的基礎上利用雅各比矩陣對非線性方程進行了線化,線化后的方程利用多槳葉坐標變換轉換到固定系下后,利用直接特征值分析(地面、懸停)或floquet理論(前飛)對系統進行了穩定性分析;同時,對系統進行了瞬態響應分析;在系統達到穩態的基礎上進行掃頻激勵,用fft變換求得系統頻率,進而用移動矩形窗方法分析得到系統的阻尼。