Digital control of a PVTOL aircraft

In this work a multirate digital control scheme for an ε-nonminimum-phase systems is proposed and the case study of a PVTOL aircraft model is developed. Considering the nominal plant, it is firstly shown, on the basis of an exact sampled dynamics obtained under preliminary feedback and diffeomorphism, that an exact dead beat control scheme can be designed. This method was proposed by Chelouah et al. (1993), and concerns digital control of nonholonomic systems. To reduce the effects of the perturbation parameter ε a control scheme, which allows to take into account this effect up to a desired fixed order of approximation, is proposed. In this paper, for computational reasons, only the first order of approximation is considered. Simulation results comparing previous continuous time control schemes and the present digital one are given