Dynamic feedback H ∞ control for discrete singular systems with time–varying delays

Bifurcation control deals with the modification of the bifurcation characteristics of a parameterized nonlinear system by a judiciously designed control input. We consider the problem of dynamic feedback control of bifurcations. In particular, previous results on the control of bifurcations using washout filters are extended to some general forms of dynamic feedback controllers. It is shown that high-pass filters such as washout filters can be represented by a special form of dynamic feedback controller. The control effect on bifurcations can be readily assessed by analytical formulae. These dynamic feedback controllers offer more flexibility over the original controller in bifurcation control. The results are viable for the design and analysis of nonlinear control systems involving bifurcations.

The problem of robust strictly passive analysis for a class of uncertain discrete singular time-delay systems is investigated in this paper. The discrete singular systems under consideration involve constant time-delay and norm-bounded uncertainties. Based on an integral inequality, a new sufficient condition is firstly obtained, which guarantees that the discrete singular time-delay systems are admissible and strictly passive. Meanwhile, the sufficient condition for robust strictly passive is also obtained in terms of linear matrix inequality (LMI). A numerical example is also given to demonstrate the applicability of the proposed method.

The dynamic linear state feedback control problem is addressed for a class of nonlinear systems subject to time-delay. First, using the dynamic change of coordinates, the problem of global state feedback stabilization is solved for a class of time-delay systems under a type of nonhomogeneous growth conditions. With the aid of an appropriate Lyapunov-Krasovskii functional and the adaptive strategy used in coordinates, the closed-loop system can be globally asymptotically stabilized by the dynamic linear state feedback controller. The growth condition in perturbations are more general than that in the existing results. The correctness of the theoretical results are illustrated with an academic simulation example.

The aim of this paper is to develop a new approach for a solution of the model following control (MFC) problem with a dynamic compensator by using linear matrix inequalities (LMIs). TheH1 model following control problem is derived following LMI formulation. First, the H1 optimal control problem is revisited by referring to Lemmas assuring all admissible controllers minimizing the H1 norm of the transfer function between the exogenous inputs and the outputs. Then, the solvability condition and a design procedure for a two degrees of freedom (2 DOF) dynamic feedback control law is introduced. The existence of a 2 DOF dynamic output feedback controller for the model following control is proven and the stability of the closed-loop system is satisfied by assuring the Hurwitz condition. The benchmark thermal process (PT-326) as the first order process with timedelay is regulated by the presented 2 DOF dynamic output feedback controller. The simulation results illustrate that the presented controller regulates a system with dead-time as a large set of generic industrial systems and the H1 norm of the closed-loop system is assured less than the H1 norm of the desired model system.

New results on dynamic output state feedback stabilization of some class of time-varying nonlinear Caputo derivative systems

Dynamic feedback control strategies are proposed for the asymptotic stabilization and asymptotic output tracking problems, associated with the operation of flexible joint manipulators. Smooth dynamical linearizing feedback controllers, as well as dynamical sliding mode regulators, are derived within the context of M. Fliess's (1989) generalized observability canonical form (GOCF). The GOCF is obtained by means of a state elimination procedure, carried out on the system of differential equations describing the manipulator dynamics. The remarkable feature of this new approach lies in the fact that a truly effective smoothing of the sliding mode controlled responses is possible while substantially reducing the chattering in the control input torque. Simulation examples are given that illustrate the performance of the proposed controllers.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

This paper is devoted to the finite‐time local piecewise control for parabolic partial differential equations (PDEs) by using dynamic output feedback control strategy, where the controller is designed as an ordinary differential equation (ODE). This makes the closed‐loop system PDE‐ODE coupled, which is employed to accurately describe the dynamics of the PDE system. According to the constructed PDE‐ODE coupled model, a local piecewise dynamic feedback control law is first proposed. Sufficient conditions on finite‐time stabilisation of the parabolic PDE‐ODE coupled system by the suggested feedback controller are then developed in the sense of both complete spatial measurement and incomplete spatial measurement of the observed output of the PDE system, respectively. Finally, the issues regarding the finite‐time stabilisation of the closed‐loop system is converted into the feasibility of matrix inequalities, and some simulation studies are provided to verify the effectiveness of the proposed results.

Dynamic feedback control of day-to-day traffic disequilibrium process

In this article, the high-order fully actuated (HOFA) system approach is applied to study the matrix threshold strategy dynamic event-triggered control problem of a single-link flexible joint robot system (SFJRS). First, the SFJRS is transformed into an HOFA system model by using the recursive "ascending dimension and descending order" method. On this basis, different from the traditional method based on the state-space model, a novel matrix threshold strategy dynamic event-triggered control scheme based on the HOFA system approach is proposed, which not only simplifies the control design but also greatly saves communication resources. It is proved that the closed-loop systems are asymptotically stable under the proposed control strategy. Finally, the superiority of the HOFA system approach and the matrix threshold strategy dynamic event-triggered control method is demonstrated through two different simulation experiments.

A 24-GHz power amplifier (PA) for 5G communication is implemented with a 65-nm bulk CMOS process, which adopts analog linearization techniques of dynamic feedback control (DFC) and an adaptive bias control (ADB). The DFC decreases feedbacks and the ADB increases a gate bias of common sources (CSs) with an increase of the input signal power so that the DFC improves gain flatness and peak efficiency, and the ADB increases high power gain, saturation power, and peak efficiency. These analog linearization techniques lower the IMD3 by improving the AM-AM and AM-phase modulation (PM) of the PA. The proposed PA shows a saturation power of 18.7 dBm, a 1-stage PA gain of 15.3 dB, and a peak PAE of 37.2% with the 24.29-GHz continuous wave signal measurement. It also shows a linear power of 12.9 dBm and a linear PAE of 14.8% with a two-tone signal measurement that has a center frequency of 24.49 GHz and a bandwidth of 80 MHz.

In this paper, a global robust stabilizer is proposed for a class of uncertain linear systems. The stabilizer is a dynamic state feedback controller, which guarantees finite-time convergence to the origin, as well as Lyapunov stability. We first augment the given plant by one additional dynamics and design the stabilizer by combining backstepping and the idea of a dynamic exponent scaling method. Validating the design only on a half-space of the extended state space, the closed-loop system becomes smooth on the space, so that the solution is unique there. In addition, we prove that any solution will reach the origin (by escaping the half-space) in finite time and that the control signals converge to zero by adopting the new concept of degree indicator.

A new model-based dynamic resistive wall mode (RWM) identification and feedback control algorithm has been developed. While the overall RWM structure can be detected by a model-based matched filter in a similar manner to a conventional sensor-based scheme, it is significantly influenced by edge-localized-modes (ELMs). A recent study suggested that such ELM noise might cause the RWM control system to respond in an undesirable way. Thus, an advanced algorithm to discriminate ELMs from RWM has been incorporated into this model-based control scheme, dynamic Kalman filter. Specifically, the DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] resistive vessel wall was modeled in two ways: picture frame model or eigenmode treatment. Based on the picture frame model, the first real-time, closed-loop test results of the Kalman filter algorithms during DIII-D experimental operation are presented. The Kalman filtering scheme was experimentally confirmed to be effective in discriminating ELMs from RWM. As a result, the actuator coils (I-coils) were rarely excited during ELMs, while retaining the sensitivity to RWM. However, finding an optimized set of operating parameters for the control algorithm requires further analysis and design. Meanwhile, a more advanced Kalman filter based on a more accurate eigenmode model has been developed. According to this eigenmode approach, significant improvement in terms of control performance has been predicted, while maintaining good ELM discrimination.

Cooperative output regulation problem for linear time-delay multi-agent systems under switching network

Mechanical systems are often only equipped with position measurement encoders and obtain the velocity signal by differentiation.However, differentiation largely amplifies noise.In this paper we look at dynamic feedback control of Euler-Lagrange mechanical systems.Dynamic feedback is often used to avoid velocity measurements in the control feedback.In the Euler-Lagrange literature it is shown that the dynamic extension realizes an approximate differentiator, justifying its application.We show in this paper that the dynamic extension used in the Euler-Lagrange literature actually realizes a leadcompensator, proving that a lead-compensator can also globally asymptotically stabilize a nonlinear mechanical systems.Furthermore, based on the lead-compensator structure it is then possible to offer a frequency approach to tune the controller gains.

This paper investigates the static-feedback guaranteed cost control problem for linear systems with actuator faults including outage and loss of effectiveness. Under the actuator redundancy condition, theoretical analysis shows that a static-feedback guaranteed cost controller can always be well designed to ensure that the resulting closed-loop system is stable with desirable quadratic performance. In particular, the feedback gain can be determined through the solution of a modified algebraic Riccati equation. Furthermore, extension to the system with uncertainties is further studied. Compared with the dynamic feedback controller, the static-feedback controller consists only of logical gates/modules and it does not require any memory element, and hence it is simplest in a design perspective. Different from the existing results, the severe and time-varying actuator outage faults can be handled very well by the proposed control strategy. Finally, simulation on a linearised reduced-order aircraft system is provided for verifying the theoretical results.