This paper considers the problem of a nonlinear H∞ design for a laboratory twin rotor system. This mechanical device features a highly nonlinear strongly coupled dynamics, which constitutes a challenge for many classical linear control techniques. The approach presented in this paper considers a nonlinear H∞ disturbance rejection procedure on the reduced dynamics of the rotors, including integr...

This work introduces a novel approach to stability and stabilization of nonlinear systems with delayed multivariable inputs; it provides exponential estimates as well as a guaranteed cost of the system solutions. The result is based on an exact convex representation of the nonlinear system which allows a Lyapunov–Krasovskii functional to be applied in order to obtain sufficient conditions in th...

By making use of a suite of programs for designing profile geometry, cutter geometry and predicting the thermodynamic performance of a twin screw compressor, this paper investigates techniques of obtaining an optimised rotor cutter blade design. The techniques for using different geometric schemes for setting clearances are explained, and the techniques for optimising main manufacturing paramet...

this work deals with effects of asymmetric stiffness on the dynamic behaviour of the rotor system. the analysis is presented through an extended lagrangian hamiltonian mechanics on the asymmetric rotor system, where symmetries are broken in terms of the rotor stiffness. the complete dynamics of asymmetries of rotor system is investigated with a case study. in this work, a mathematical model is ...

The paper is focused on control of a Twin Rotor MIMO System – a laboratory model constructed by Feedback Instruments Ltd. The system consists of a two rotors attached to a bar which can freely turn around two axes. System behaviour resembles a simple helicopter. Significant cross-coupling can be observed and the system is nonlinear. A model in the MATLAB/Simulink environment, which was develope...

Some results from a procedure for optimising the geometrical parameters of a refrigeration twin screw compressor, such as the basic geometrical parameters of its profile and the position of its discharge port etc., were presented by the authors at the International Compressor Engineering Conference at Purdue, 1992. In this paper the optimisation technique is developed by making use of programs ...

In this paper the problem of robust fault detection using an interval observer for dynamic systems characterized by LPV (Linear Parameter Varying) models is presented. The observer face the robustness problem using two complementary strategies. Parametric modeling uncertainties are considered unknown but bounded by intervals. Their effect is addressed using an interval state observation method ...