Nonlinear robust hierarchical control for nonlinear uncertain systems.
Nonlinear stabilization by adding integrators
Nonlinear stabilizing control of an uncertain bioprocess model
In this paper we consider a nonlinear model of a biological wastewater treatment process, based on two microbial populations and two substrates. The model, described by a four-dimensional dynamic system, is known to be practically verified and reliable. First we study the equilibrium points of the open-loop system, their stability and local bifurcations with respect to the control variable. Further we propose a feedback control law for asymptotic stabilization of the closed-loop system towards a...
Nonnegativity of uncertain polynomials.
Nonparametric instrumental variables for identification of block-oriented systems
A combined, parametric-nonparametric identification algorithm for a special case of NARMAX systems is proposed. The parameters of individual blocks are aggregated in one matrix (including mixed products of parameters). The matrix is estimated by an instrumental variables technique with the instruments generated by a nonparametric kernel method. Finally, the result is decomposed to obtain parameters of the system elements. The consistency of the proposed estimate is proved and the rate of convergence...
Non-quadratic performance design for Takagi-Sugeno fuzzy systems
This paper improves controller synthesis of discrete Takagi-Sugeno fuzzy systems based on non-quadratic Lyapunov functions, making it possible to accomplish various kinds of control performance specifications such as decay rate conditions, requirements on control input and output and disturbance rejection. These extensions can be implemented via linear matrix inequalities, which are numerically solvable with commercially available software. The controller design is illustrated with an example.
Nonquadratic stabilization of continuous-time systems in the Takagi-Sugeno form
This paper presents a relaxed scheme for controller synthesis of continuous- time systems in the Takagi-Sugeno form, based on non-quadratic Lyapunov functions and a non-PDC control law. The relaxations here provided allow state and input dependence of the membership functions’ derivatives, as well as independence on initial conditions when input constraints are needed. Moreover, the controller synthesis is attainable via linear matrix inequalities, which are efficiently solved by commercially available...
Nonregular decoupling with stability of two-output systems
In this paper we present a solution to the decoupling problem with stability of linear multivariable systems with 2 outputs, using nonregular static state feedback. The problem is tackled using an algebraic-polynomial approach, and the main idea is to test the conditions for a decoupling compensator with stability to be feedback realizable. It is shown that the problem has a solution if and only if Morse’s list is greater than or equal to the infinite and unstable structure of the proper and stable...
Nonsmooth optimal regulation and discontinuous stabilization.
Normalized finite fractional differences: Computational and accuracy breakthroughs
This paper presents a series of new results in finite and infinite-memory modeling of discrete-time fractional differences. The introduced normalized finite fractional difference is shown to properly approximate its fractional difference original, in particular in terms of the steady-state properties. A stability analysis is also presented and a recursive computation algorithm is offered for finite fractional differences. A thorough analysis of computational and accuracy aspects is culminated with...
Note on stability of a control system
Note on stability of a linear homogeneous control system
Notes on and robustness tests
An upper bound for the complex structured singular value related to a linear time-invariant system over all frequencies is given. It is in the form of the spectral radius of the -norm matrix of SISO input-output channels of the system when uncertainty blocks are SISO. In the case of MIMO uncertainty blocks the upper bound is the -norm of a special non-negative matrix derived from -norms of SISO channels of the system. The upper bound is fit into the inequality relation between the results of...
Numerical algorithm for nonsmooth stabilization of triangular form systems
Numerical and symbolic applications of MATHEMATICA.
Numerically generated path stabilizing controllers: Use of preliminary feedback