Robust nonlinear flight control of a high-performance aircraft

Abstract

Abstract-This paper considers probabilistic robust control of nonlinear uncertain systems. A combination of stochastic robustness and dynamic inversion is proposed for general systems that have a feedback-linearizable nominal system. In this paper, the stochastic robust nonlinear control approach is applied to a highly nonlinear complex aircraft model, the high-incidence research model (HIRM). The model addresses a high-angle-of-attack enhanced manual control problem. The aim of the flight control system is to give good handling qualities across the specified flight envelope without the use of gain scheduling and also to provide robustness to modeling uncertainties. The proposed stochastic robust nonlinear control explores the direct design of nonlinear flight control logic. Therefore, the final design accounts for all significant nonlinearities in the aircraft's high-fidelity simulation model. The controller parameters are designed to minimize the probability of violating design specifications, which provides the design with good robustness in stability and performance subject to modeling uncertainties. The present design compares favorably with earlier controllers that were generated for a benchmark design competition.

SDRE and LQR Controls Comparison Applied in High-Performance Aircraft in a Longitudinal Flight

“…This strategy can also be observed on [5] with nonlinear automatic flight control. Approaches developed by [6] with robust probabilistic control showed an increase in control performance. Considering current approaches with adaptative control proposes, such as the proposal by [7], with a multivariate allocation of adaptive control based on the spline to compensate for aerodynamic uncertainties, or also, proposed by [8] where we have an adaptive control based on Lyapunov function for longitudinal dynamics.…”

“…The following parameters will be considered for the numerical simulations: aircraft speed V0=277. 3 shows the time histories of the aircraft's longitudinal system represented by (6). According to the behavior shown in Fig.…”

“…Fig.3shows the time histories of the aircraft's longitudinal system represented by(6). According to the behavior shown in Fig.3, it is possible to observe the variation of the main states of the aircraft over time, implying a long response rate, or even the aircraft stall situation as seen in Fig.3(c), which could damage some systems and even cause the aircraft failure.…”

Direct Methodology for Constrained System Analysis with Applications to Aircraft Dynamics

“…In linear control, the input is proportional to the linearized output, and it is widely used due to the ease of implementation. However, recently researchers have also used nonlinear flight-control design techniques such as robust control [13] and sliding mode control [14] in the entire flight envelope to ensure appropriate handling qualities in the presence of model uncertainties. In this paper, the design of linear feedback-control laws for two tasks, first for assigning the short-period mode eigenvalues as desired by handling and flying qualities and second for keeping the short-period mode eigenvalues at the desired location for all level-flight trims, is carried out as a second example problem to show the usefulness of the direct continuation methodology.…”

Dynamics and Performance of Tailless Micro Aerial Vehicle with Flexible Articulated Wings

“…The stability of each mode can be analyzed independently, with the other mode contributing a constant term whose value is a function of the mode being analyzed. This property is used routinely for deriving literal approximations to aircraft dynamic modes [33], and as basis for control design [34]. It must be noted that a sufficiently strong coupling between the two modes can alter the conclusions significantly.…”