Parameter Estimation of Actuators for Benchmark Active Control Technology (BACT) Wind Tunnel Model with Analysis of Wear and Aerodynamic Loading Effects

Abstract This report describes the development of transfer function models for thetrailing-edge and upper and lower spoiler actuators of the Benchmark ActiveControl Technology (BA CT) wind tunnel model for application to control systemanalysis and design. A simple nonlinear least-squares parameter estimationapproach is applied to determine transfer function parameters from frequencyresponse data. Unconstrained quasi-Newton minimization of weighted frequencyresponse error was employed to estimate the transfer function parameters. Ananalysis of the behavior of the actuators over time to assess the effects of wearand aerodynamic load by using the transfer function models is also presented.The frequency responses indicate consistent actuator behavior throughout thewind tunnel test and only slight degradation in effectiveness due to aerodynamichinge loading. The resulting actuator models have been used in design, analysis,and simulation of controllers for the BACT to successfully suppress flutter over awide range of conditions.