Computational analysis on actuator failures of flexible aircraft

Abstract

A coupled model of aeroservoelasticity and hydraulic actuator used for failure simulation is presented. The mathematical model composites rigid-body modes, elastic modes, control surface modes, unsteady aerodynamic forces and failure models (jam, loss of control (LOC), oscillatory failure, and hydraulic fluid leakage). A clear framework of coupling method of airplane aeroelastic equation and control surface dynamic equation is provided to study the impacts of surface failures on rigid-elastic motion of airplane. The coupled model is shown to be effective in evaluation of gust response in both discrete gust and continuous turbulence conditions compared with results obtained from the 3-order simplified actuator. Examples of gust load alleviation (GLA) system with LOC of ailerons are given. Results show that total loss of function of GLA system is caused by the LOC. With continuous turbulence excitation, the failure loads is several times larger than that without GLA system.

An Output-Feedback Design Approach for Robust Stabilization of Linear Systems With Uncertain Time-Delayed Dynamics in Sensors and Actuators

“…In the synthesis conditions, K(α) = W −1 Z(α) guarantees the robust state-feedback stabilization of ẇ(t) = ( Ā(α) + B(α)K(α))w(t) with lower bound β on the closed-loop system decay rate. 2 Clearly, the conditions presented in ( 24) are of infinitedimension, as they are dependent on the uncertain parameter α. Therefore, some manipulation over these constraints have to be performed to obtain an equivalent finite-dimension problem.…”

“…Due to the intrinsic aeroelastic nature of such systems, we observe a strong interaction between the aircraft structure and its control and actuator systems. Such interconnection is referred in the specialized literature as aeroservoelasticity [2]. As a consequence, for properly representing the system in order to achieve desired…”

Synthesis Of Robust Control Systems With Dynamic Actuators And Sensors Using A Static Output Feedback Method

“…With the development of more sophisticated technology and equipment, it tends to become increasingly relevant to consider the dynamics of sensors and actuators in modern control problems. For instance, sensors, actuators, control law, and control surfaces could affect the stability and performance of modern lightweight aircraft (Yang et al, 2018;Al-Jiboory et al, 2017;Stanford, 2016), due to aeroservoelasticity, a design characteristic inherent of such airplanes (Botez et al, 2008). In fact, the negative impact of neglecting of sensor and actuator dynamics has been long known (Young and Kokotovic, 1982;Leitmann et al, 1986).…”