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This brief deals with the application of linear parameter varying control concepts to the design of a full envelope flight control system for commercial aircrafts. The proposed controller is fixed to have a multivariable proportional-integral structure. A linear matrix inequalities-based technique is proposed to account for variations both in the reference model and in the plant. Some numerical simulations show the effectiveness of the proposed technique all over the aircraft operating envelope. © 2007 IEEE.

In this paper the problem of controlling a plasma wind tunnel, to simulate the re-entry conditions of space vehicles by reproducing desired trajectories in pressure and temperature on a test model, is considered. The proposed control strategy consists of two terms: a feedforward control action to guarantee the trajectory following in absence of external disturbances, and an output feedback control action to counteract possible misalignements between the desired trajectory and the actual one. The feedback controller is designed in the discrete-time setting. It is shown that the linearized model of the plant can be described by a LPV system depending on nine uncertain parameters; eight of such parameters exhibit small excursions and no bound on their rate of variation is available, while the last parameter turns out to be slowly-varying and a bound on the rate of variation is known. The controller is designed so as to robustly stabilize the overall closed loop system versus the above-mentioned uncertain parameters; an ad hoc technique, which takes into account the information on the rate of variation of the slowly-varying parameter, is used. Numerical simulations are carried out on the nonlinear system to show the effectiveness of the proposed control scheme.

In this work we deal with the problem of controlling the current in an electric arc heater by means of the delay angle of a 70 MW electric power system thyristor bridge. To guarantee the current regulation inside the arc heater we propose a control scheme consisting of two actions: a feedforward control action obtained off-line by means of a numerical nonlinear inversion of the model and implemented on-line with a look-up table to guarantee the perfect regulation in absence of external disturbances, and an output feedback control action to counteract possible disturbances acting during the operating of the arc heater. Since the electric linearized model depends on a number of uncertain parameters, the feedback control action is designed so as to guarantee robust stabilization of the closed loop; moreover constraints regarding the speed of convergence are imposed. Simulation results are provided for the whole nonlinear scheme.