Improved Dynamic Surface Control for Uncertain Nonlinear Systems With Application to Fighter Jet System

An improved dynamic surface control (IDSC) method is proposed for a class of strict-feedback nonlinear systems with internal uncertainties and external disturbances. First, compared with the typical first-order sliding-mode differentiator, this article presents an improved method to obtain the first-order differential approximation of the virtual control signals, which tackles the obstacle of “explosion of complexity.” Second, to eliminate the effect of filtering errors that exist in traditional dynamic surface control method, in this article, the tracking errors are directly constructed using the virtual control signal. Third, composite disturbances were estimated and compensated by designing a novel disturbance observer, which eliminates the limitations that the disturbance terms must be differentiable or even slow tensors. Finally, to illustrate that the proposed method has a great ability to suppress fast time-varying and nondifferentiable disturbances, the simulation results of a numerical example and a practical example of a modern advanced fighter jet system were presented.