Three-Time Scale Singular Perturbation Control for a Radio-Control Helicopter on a Platform

Abstract

Control of rotatory wing aircrafts represents a very challenging task due to the nonlinearities and inherent instabilities present in such systems. The versatility of rotorcrafts allows them to perform almost any task that no conventional aircraft can do, but this ability is ultimately associated to the stability and control characteristics obtained via automatic control design. These stability and control characteristics come at the price of complex control designs in order to deal with these highly nonlinear aerospace systems. Historically, classical linear control techniques such design via root locus, frequency response techniques, state space techniques, PID controllers, or gain scheduling to name few, have been sufficient to obtain reasonable control responses of aerospace systems. The evolution of the aerospace industry, and the consequent improvement of technologies, have increased the performance requirements of all systems in general, which has called for better control designs that can deal with more complex systems, making linear control techniques insufficient to cope with the industry demands. Specifically, in the area of aerospace systems, a wide range of different nonlinear control techniques have been studied to deal with the nonlinear dynamics of such systems. From singular perturbation, feedback linearization, dynamic inversion, 10 sliding mode control, or backstepping control methods, to name few. Neural Networks (NN) are also included within the realm of nonlinear control techniques, and seem to provide improved robustness properties under system uncertainties. Some of works include Adaptive Critic Neural Network (ACNN) based