Renan Lima Pereira

Design of gain-scheduled controllers based on parametric H ∞ loop shaping

Synthesis conditions for the design of gain-scheduled controllers based on a parametric H ∞ loop shaping approach are presented for linear parameter-varying (LPV) systems. The main procedures to find such robust controllers are given. The design problem has been formulated via static H ∞ output feedback control, considering the uncertainty as normalised coprime factors of the shaped plant. The shaped plant must be chosen appropriately to satisfy the robustness requirements of the closed-loop system. The design procedure features free parameters to increase the flexibility of the design ensuring robust stabilisation of the LPV system. For the existence of a gain-scheduled parametric H ∞ loop shaping controller, a set of sufficient conditions has been derived in an LMI framework. Numerical examples illustrate the use of the proposed control design with applications to two physical systems: a two-mass-spring system and a hover system.

Experimental investigation of nonlinear controllers applied to a 3DOF hover: SMC via ALQR approach

This paper presents an application of sliding mode controllers obtained via amplified linear quadratic regulator (ALQR) strategy to a hover with three degrees of freedom. The purpose of the designed control system is to track reference trajectories and ensure performance and stability in spite of disturbance, noise and unmodeled dynamics. Simulations were performed using MATLAB/Simulink in order to verify/compare the performance of the nonlinear controllers proposed. For validation of the algorithm a didactic plant (3DOF Hover) was chosen produced by Quanser Consulting, that simulates typical behaviors of an VTOL (“vertical taking-off landing”) aircraft, also known as X4-flyer. The dynamic of the hover can be described by a 6th order model taking as state variables the angles of yaw, pitch, roll and associated rates. The experiments showed that designed nonlinear controllers using sliding mode control via ALQR are robust to noises and for a range of unmodeled nonlinearities.

Projeto de um controlador robusto h∞ com formatação de malha via dml aplicado em um hover

O proposito deste trabalho e apresentar as possiveis vantagens do emprego de um controlador robusto H∞ com formatacao de malha usando desigualdades matriciais lineares (DML) para resolver o problema de rastreamento de referencias e estabilizacao robusta em um hover com tres graus de liberdade. Este sistema foi produzido pela empresa Quanser Consulting a fim de simular comportamentos tipicos de uma aeronave VTOL (vertical taking-off landing), tambem conhecido como X4-flyer. A formulacao adotada neste estudo consiste na sintese H∞ usando uma configuracao de quatro blocos. Esta configuracao garante a estabilidade robusta do sistema em malha fechada contra incerteza nao-estruturada descrita via fatoracao coprima. Sao apresentados resultados experimentais obtidos com o uso do controlador H∞.