guaranteed cost control of discrete linear systems.
optimal decoupling of previewed signals in the discrete-time case
The synthesis of a feedforward unit for optimal decoupling of measurable or previewed signals in discrete-time linear time-invariant systems is considered. It is shown that an optimal compensator can be achieved by connecting a finite impulse response (FIR) system and a stable dynamic unit. To derive the FIR system convolution profiles an easily implementable computational scheme based on pseudoinversion (possibly nested to avoid computational constraints) is proposed, while the dynamic unit...
-optimal rejection with preview: geometric constraints and dynamic feedforward solutions via spectral factorization
In this work, a feedforward dynamic controller is devised in order to achieve H2-optimal rejection of signals known with finite preview, in discrete-time systems. The feedforward approach requires plant stability and, more generally, robustness with respect to parameter uncertainties. On standard assumptions, those properties can be guaranteed by output dynamic feedback, while dynamic feedforward is specifically aimed at taking advantage of the available preview of the signals to be rejected, in...
control design for an adaptive optics system
In this paper we first present a full order controller for a multi- input, multi-output (MIMO) adaptive optics system. We apply model reduction techniques to the full order controller and demonstrate that the closed-loop (CL) system with the reduced order controller achieves the same high level of performance. Upon closer examination of the structure of the reduced order controller it is found that the dynamical behavior of the reduced order controller can be accurately approximated by...
control of discrete-time linear systems constrained in state by equality constraints
In this paper, stabilizing problems in control design are addressed for linear discrete-time systems, reflecting equality constraints tying together some state variables. Based on an enhanced representation of the bounded real lemma for discretetime systems, the existence of a state feedback control for such conditioned stabilization is proven, and an LMI-based design procedure is provided. The control law gain computation method used circumvents generally an ill-conditioned singular design task....
Hankel-matrix approach to invertibility of linear multivariable systems
Hard and soft sub-time-optimal controllers for a mechanical system with uncertain mass
Hierarchical decomposition of fuzzy controllers based on meta-knowledge.
This paper focuses on the problem of decomposing multivariable fuzzy controllers using a hierarchical approach based on the application of meta-knowledge. Usually, hierarchical fuzzy systems are based on a cascade structure of fuzzy logic controllers where the output of each level is considered as one of the inputs to the following level. The paper introduces a different approach to the idea of hierarchy, where the output of a level is considered not as input to the following level controller but...
High order necessary optimality conditions.
High-gain feedback and sliding modes in infinite dimensional systems
High-Order Control Variations and Small-Time Local Controllability
The importance of “control variations” for obtaining local approximations of the reachable set of nonlinear control systems is well known. Heuristically, if one can construct control variations in all possible directions, then the considered control system is small-time locally controllable (STLC). Two concepts of control variations of higher order are introduced for the case of smooth control systems. The relation between these variations and the small-time local controllability is studied and...
High-performance simulation-based algorithms for an alpine ski racer's trajectory optimization in heterogeneous computer systems
Effective, simulation-based trajectory optimization algorithms adapted to heterogeneous computers are studied with reference to the problem taken from alpine ski racing (the presented solution is probably the most general one published so far). The key idea behind these algorithms is to use a grid-based discretization scheme to transform the continuous optimization problem into a search problem over a specially constructed finite graph, and then to apply dynamic programming to find an approximation...
Hölder equivalence of the value function for control-affine systems
We prove the continuity and the Hölder equivalence w.r.t. an Euclidean distance of the value function associated with the L1 cost of the control-affine system q̇ = f0(q) + ∑j=1m ujfj(q), satisfying the strong Hörmander condition. This is done by proving a result in the same spirit as the Ball–Box theorem for driftless (or sub-Riemannian) systems. The techniques used are based on a reduction of the control-affine system to a linear but time-dependent one, for which we are able to define a generalization...
Homogenization of constrained optimal control problems for one-dimensional elliptic equations on periodic graphs
We are concerned with the asymptotic analysis of optimal control problems for -D partial differential equations defined on a periodic planar graph, as the period of the graph tends to zero. We focus on optimal control problems for elliptic equations with distributed and boundary controls. Using approaches of the theory of homogenization we show that the original problem on the periodic graph tends to a standard linear quadratic optimal control problem for a two-dimensional homogenized system, and...
Homogenization of constrained optimal control problems for one-dimensional elliptic equations on periodic graphs
We are concerned with the asymptotic analysis of optimal control problems for 1-D partial differential equations defined on a periodic planar graph, as the period of the graph tends to zero. We focus on optimal control problems for elliptic equations with distributed and boundary controls. Using approaches of the theory of homogenization we show that the original problem on the periodic graph tends to a standard linear quadratic optimal control problem for a two-dimensional homogenized system,...
Homogenization of quasilinear optimal control problems involving a thick multilevel junction of type 3 : 2 : 1
We consider quasilinear optimal control problems involving a thick two-level junction Ωε which consists of the junction body Ω0 and a large number of thin cylinders with the cross-section of order 𝒪(ε2). The thin cylinders are divided into two levels depending on the geometrical characteristics, the quasilinear boundary conditions and controls given on their lateral surfaces and bases respectively. In addition, the quasilinear boundary conditions depend on parameters ε, α, β and the...
Homogenization of quasilinear optimal control problems involving a thick multilevel junction of type 3 : 2 : 1∗
We consider quasilinear optimal control problems involving a thick two-level junction Ωε which consists of the junction body Ω0 and a large number of thin cylinders with the cross-section of order 𝒪(ε2). The thin cylinders are divided into two levels depending on the geometrical characteristics, the quasilinear boundary conditions and controls given on their lateral surfaces and bases respectively. In addition, the quasilinear boundary...
Homogenization of quasilinear optimal control problems involving a thick multilevel junction of type 3 : 2 : 1∗
We consider quasilinear optimal control problems involving a thick two-level junction Ωε which consists of the junction body Ω0 and a large number of thin cylinders with the cross-section of order 𝒪(ε2). The thin cylinders are divided into two levels depending on the geometrical characteristics, the quasilinear boundary conditions and controls given on their lateral surfaces and bases respectively. In addition, the quasilinear boundary...
Hopf bifurcation analysis of some hyperchaotic systems with time-delay controllers
A four-dimensional hyperchaotic Lü system with multiple time-delay controllers is considered in this paper. Based on the theory of Hopf bifurcation in delay system, we obtain a simple relationship between the parameters when the system has a periodic solution. Numerical simulations show that the assumption is a rational condition, choosing parameter in the determined region can control hyperchaotic Lü system well, the chaotic state is transformed to the periodic orbit. Finally, we consider the differences...
Hoptf bifurcation from infinity for planar control systems.
Symmetric piecewise linear bi-dimensional systems are very common in control engineering. They constitute a class of non-differentiable vector fields for which classical Hopf bifurcation theorems are not applicable. For such systems, sufficient and necessary conditions for bifurcation of a limit cycle from the periodic orbit at infinity are given.