The tracking control problem of a strongly nonlinear MIMO system is presented. The system shares some features with a helicopter, such as important interactions between the vertical and horizontal motions. The dedicated IO board allows for control, measurements and communication with a PC. The RTWT toolbox in the MATLAB environment is used to perform real-time experiments. The control task is to track a predefined reference trajectory. A mathematical model of the system, containing experimental characteristics, is used to design the controllers: a multidimensional PD, a suboptimal controller in the sense of a quadratic performance index and a variable gain controller.