Research On Output Feedback Control Of Interconnected Large-Scale Systems Based On Interval Observer

With the increasing scale of control systems in commercial production and factual life,the increasing complexity of related control systems,the control of interconnected large-scale systems has attracted more and more scholars’attention.Due to the large number of subsystems in the interconnected large-scale system,there are unpredictable external perturbation in the actual production process,and the interconnection items have an impact on each subsystem.These conditions will affect system performance and even lead to the instability of the system.Therefore,the output feedback control method is designed for interconnected large-scale systems with uncertain nonlinearity interconnections.The main contents are as follows:For a class of linear interconnected large-scale systems with uncertain nonlinearity interconnections and external perturbation,an output feedback controller design method based on interval observer is proposed.Firstly,an interval observer is constructed for each subsystem to ensure the interval between the system state and the system estimated state.Secondly,the state feedback controller is built for each interval observer system,rather than the output feedback controller directly designed for the original system.Subsequently,considering the existence of unknown nonlinear interconnections,a cyclic-small-gain condition is employed,the stability proof of closed-loop subsystem is given,and L_∞performance is introduced to suppress unknown external disturbances.Finally,the Metzler condition is relaxed by coordinate transformation,and a controller design algorithm is given.For a class of nonlinear interconnected large-scale systems with uncertain nonlinearity interconnections and external perturbation,a piecewise output feedback controller design method is proposed.Firstly,the T-S fuzzy model is used to describe nonlinear interconnected large-scale system.Considering the membership function of trapezoidal structure,the output space of each interconnected subsystem is divided into operating and interpolation regions.A piecewise interval observer is constructed for each subsystem base on region division.Secondly,a piecewise state feedback controller is proposed for each piecewise interval observer system.Then,the stability of the closed-loop subsystem is analyzed and the disturbance suppression performance is satisfied.The form of linear matrix inequality is given.Finally,the design algorithm of piecewise controller is given by relaxing the Metzler condition with the coordinate transformation.Corresponding to the above contents,three orders interconnected inverted pendulum system models are established.The effectiveness of the suggested method is verified base on simulation.