[en] ASDEX Upgrade is a tokamak with a reactor-like poloidal divertor configuration now under construction at IPP, and scheduled to go into operation in 1988. In addition to its main object of simulating a reactor-relevant plasma boundary, it is also characterized by reactor-typical features of plasma position and parameter control. Owing to the plasma elongation, the placing of poloidal field coils outside the toroidal field coils and the asymmetry of the poloidal configuration, it involves all the major control problems of present reactor designs, such as vertical instability, high control power required, and mutual dependence of all control variables. The central issue of this paper is to derive a general formulation of model equations for the plasma equilibrium in a tokamak as a basis for positional control considerations. The results are applied to the special case of ASDEX Upgrade for simulating some exemplary control actions