RETRACTED: Flexible performance design for the H_∞ loop-shaping control based on the linear matrix inequality approach: Application to the coaxial rotor helicopter

Abstract

This article introduces a new H ' loop-shaping control to decrease the complexity of the appropriate selection of the required performance for a coaxial rotor helicopter with unpredicted or unknown unstructured uncertainties. Uncertainty models are normally assumed that some knowledge of type is known. And to model a particular uncertainty as a separate model is necessary in the high-performance design of specified applications. But to model each particular uncertainty will increase the complexity of performance design for the extremely complex plant. H ' loop-shaping control provides a competitive and flexible choice to simultaneously represent a family of unpredicted and unconsidered unstructured uncertainty bounded by H ' norm. Many researches have been conducted to consider some aspects of this method, for example, the nominal stability, robustness to uncertainty, and implementation issues. However, to decrease the complexity of the appropriate selection of the required performance was not considered seriously. Therefore, a sufficient set of stable condition is derived using linear matrix inequality approach to provide the flexible performance design considering unpredicted and unknown unstructured uncertainties. Furthermore, the proposed method is applied to stabilize the attitude subsystem of a reconstructed coaxial rotor helicopter. Simulations indicate the effectiveness of the proposed method in the step response.

Multilayer hierarchical control for robotic coax-helicopter based on the H∞ robustness and mixing control scheme

“…The proportional item is used to adjust the lead and lag of the phase. 10,21 By adjusting the pre-weighted matrix coefficient, the final pre-weighted matrix is W 21 = diag 0:018s + 0:0015 s…”

“…These characteristics considerably complicate the control scheme design of coaxial rotor helicopter to achieve high-performance design. 10 Furthermore, not only nominal performance and robust performance but also the complexity, flexibility, and computation of controller design are to be considered seriously, especially in the situation of engineering application. Therefore, following our previous research, 10 we investigated the control problem of robotic coax-helicopter and proposed a new control scheme to simultaneously satisfy the different requirements and constraints of controller design.…”