Active Controls Technology Wind-tunnel Model Research Articles

Robust Generalized Predictive Control with Uncertainty Quantification

DOI: 10.2514/1.54510 This paper presents a robust predictive control method with uncertainty quantification for problems, such as online aircraft flutter suppression. The proposed approach begins by identifying the multistep output prediction matrices under various test conditions from online time-domain input/output data. Singular value decomposition is then used to characterize and quantify the parameter uncertainties of the prediction matrices. The predicted responseerrorduetoparameteruncertaintiesisintegrated intothepredictivecontroldesignprocessforrobustness. The proposed method provides an innovative and efficient way to incorporate the quantified uncertainty in predictive control design with a linear process. The proposed approach is demonstrated by application to the Benchmark Active Controls Technology wind-tunnel model.

Control of an Aeroelastic System with Actuator Saturation

The objective of this study is the semiglobal stabilization of the benchmark active control technology wind-tunnel model developed by NASA Langley Research Center. This study applies established theoretical results to the design of a saturation linear state feedback control law. The framework of this investigation is the construction of the null-controllable region and domains of attraction of the planar antistable subsystem of the higher order model in its canonical modal form. Numerical simulations at different densities of the unstable wind-tunnel system are presented that demonstrate construction and performance of the control law applied to an a priori defined subset of the null-controllable region.

Control of a Nonlinear Aeroelastic System Using Euler-Lagrange Theory

Active control of nonlinear aeroservoelastic (NL-ASE) systems is a key technology for future aircraft development. Because of the large number of nonlinear behaviors exhibited by NL-ASE systems, issues of local Lyapunov stability and structural stability must be addressed in controller design. A design methodology based on an ASE system being governed by the Euler-Lagrange (EL) equations is presented. The controller design procedure involves shaping the Lagrangian to a desired form and providing channels to dissipate energy. We consider EL systems with arbitrary Lagrangians and give sufficient conditions for local asymptotic stability and passivity. Parameter-dependent controllers are developed for large-scale changes in operating conditions and transitions across bifurcations. A procedure to design stabilizing controllers that are themselves Lyapunov and structurally stable is also given. The techniques are applied to a nonlinear version of benchmark active control technology wind-tunnel model that exhibits a Hopf bifurcation leading to flutter. Numerical results showing local asymptotic stability and structural stability for large-scale dynamic pressure variations across bifurcations are presented.