1. Introduction
In the last few years advanced control techniques capable to deal with the nonlinear systems have gained growing popularity within the aerospace community. One of the most popular method is dynamic inversion [1] which is equivalent to exact feedback linearization where a nonlinear state feedback cancels out the nonlinearity of the controlled system [2]. The main difficulty arising with the use of dynamic inversion is its big sensitivity to model inaccuracies such as parametric uncertainty or unmodeled dynamics. To overcome this difficulty different approaches are used. Under some assumptions on the dynamics robust design methods may be applied. In [3] a nonlinear H∞ robust control is utilized, whereas in [4] stochastic robust nonlinear control approach is presented. Unfortunately, both solutions have significant drawbacks. The former leads to solving of a complicated Hamilton–Jacobi partial differential inequality, the latter guarantees control performance only with some level of confidence. The easiest and most common way how to compensate the inaccuracies arising during dynamic inversion consists in using a PI controller. Such a configuration was tested on F/A-18 airplane testbed [5]. Another option is to use adaptive dynamics inversion. Such a technique is exploited either as Model Reference Adaptive Control (MRAC) scheme [6–8] where the goal is to minimize the error between the actual output and the output of the suitably chosen ∗ Corresponding author. E-mail address: husek@fel.cvut.cz (P. Husek). ˇ reference model or via Lyapunov-based design that is used to guarantee asymptotic output tracking [9]. The common disadvantage of those methods is that the bounds of nonlinear terms need to be known apriori. In [10] dynamics inversion is supported by a PID controller and Mamdani type fuzzy logic controller to control aircraft landing. A combination of backstepping control approach with dynamics inversion was introduced in [11]. In [12] dynamics inversion supported by PID controller is used to develop different nonlinear antiwindup schemes.
