Switching Rule Research Articles

Research of Non-contact Compensation AC Voltage Regulator Based on Fuzzy Strategy

The non-contact compensation type AC voltage regulator possesses the advantages of small size, high efficiency, low cost, etc. due to its simple structure and convenient control, and is widely used in the field of AC voltage regulation technology field. However, the non-contact compensation type AC voltage regulator belongs to the class of voltage regulation. And the characteristics of the discontinuous system has the disadvantages of low control precision and weak system reliability. Fuzzy control strategy, through fuzzification and approximate reasoning, can solve the problem of such discontinuous control systems. Some research work shows that using the fuzzy membership strategy to optimize the switching rules of the control system can greatly improve the control precision of the voltage regulation, that is, can improve the regulation accuracy of the AC voltage regulator. The experiment results verify that the regulation accuracy of the system after optimizing the switching rule is 5-10 times pre-set, which proves the effectiveness of the improvement.

Dynamic event-triggered [formula omitted] control for switched affine systems with sampled-data switching

This paper investigates the dynamic event-triggered L∞ control for switched affine systems under limited communication resources. For switched affine systems, affine terms bring the difficulty on the exclusion of triggering Zeno behavior. The proposed dynamic event-triggered mechanism can preclude the occurrence of triggering Zeno behavior even if affine terms and the exogenous disturbance coexist. Moreover, it further reduces the transmission frequency compared with the static version. The switching chattering phenomenon is avoided by the designed sampled-data switching rule. The co-design method of dynamic event-triggered scheme, switching controller and sampled-data switching rule is provided to achieve practical stability and the L∞ performance with respect to the external interference. Tools and techniques of time-dependent Lyapunov function are used to obtain sufficient conditions in terms of linear matrix inequalities. Finally, the effectiveness of the developed results is illustrated by an example.

Research on the driving control strategy for ISG hybrid electric vehicles

ABSTRACT To overcome such Hybrid Electric Vehicle (HEV) engine problems as high fuel consumption and poor economical efficiency when working in low-efficiency areas, this paper intends to establish the ISG light hybrid vehicle structure-based mathematical models of engines, electric motors, batteries and the whole vehicle power output first; to analyse the relationship between the engine load rate and the optimal engine fuel consumption characteristics, and then to take into consideration the performance characteristics of the motor battery output efficiency, so as to come up with the switching pattern of the ISG parallel hybrid vehicle operating mode. According to the switching rules, the primary influence parameters of the engine load rate as well as the State of Charge (SOC) were extracted and a fuzzy neural network control strategy for torque management was developed. Under the Matlab/Advisor joint simulation platform, a simulation model was established and the effectiveness of the fuzzy control strategy was verified under the typical state of cyclic operation NEDC. The simulation results indicate that the adoption of fuzzy neural network control strategy for torque management can lead to considerable advancements in engine operating efficiency–the fuel economical efficiency can be improved by about 12%.

Optimal Monetary Policy Regime Switches

An economy that switches between high and low growth regimes creates incentives for the monetary authority to change its rule. As lower growth tends to produce lower real interest rates, the monetary authority has an incentive to increase the inflation target and increase the degree of inertia in setting rates in an attempt to keep the nominal rate away from the zero lower bound. An optimizing monetary authority therefore responds to permanently lower growth by slightly increasing both the inflation target and inertia; focusing solely on the inflation target ignores a key margin of adjustment. With repeated growth rate regime switches, an optimal monetary rule that switches at the same time internalizes both the direct effects of growth regime change and the indirect expectation effects generated by switching in policy. The switching rule improves economic outcomes relative to a constant rule. A constant rule may be preferred if the monetary authority attempts a switching rule but implements the wrong rule with high enough frequency.

Stability and stabilisation of heterogeneous switched systems with arbitrary switching constraints

Heterogeneous switched systems are a class of special hybrid systems containing different dimensional subsystems. To research the stability and stabilisation of heterogeneous switched systems, a novel approach is presented to design static output feedback controllers for asymptotically stabilising heterogeneous continuous-time and discrete-time switched systems under arbitrary switching rules. This approach, which has less computation complexity, includes a main diagonal square block common Lyapunov function for stability analysis of heterogeneous switched systems and a main diagonal square block common homogeneous polynomial Lyapunov function for stabilisation of heterogeneous switched systems. In the study of stabilisation of heterogeneous switched systems, a two-step iterative method including two convex optimisation functions is established by sums of squares to express existing properties condition and solvable properties condition for determining block controller. At last, a practical example and two numerical examples are presented to show the feasibility of the proposed results.

Power management of multi-source network hydraulic system with multiple actuators

The mismatch between the load and pump sources and the restriction of energy recovery lead to large energy losses and lower energy efficiency in high power multi-actuator hydraulic systems. To obtain high energy efficiency, this paper develops a Multi-Source Network Hydraulic System (MSNHS) with multiple actuators and a corresponding power management strategy (PMS) to reduce the throttling losses and recover energy. The multiple energy-saving power modes based on the path of power transmissions, composed of different combinations of six power units with energy conversion and transfer, are implemented on MSNHS to supply and regenerate or recover power for various load conditions. Thus, the power consumption models of each power unit are established to analyze the power consumption characteristics for itself and power modes. On this basis, the switching supervisory controller is proposed to select an optimal mode for the current condition by utilizing an objective optimized function of minimal power consumption. Besides, the switching rules among power modes are designed, and the logical threshold control is presented for the multi-mode switching under different working conditions. The combination of the switching supervisory controller of optimal mode and the logical threshold control realizes the power management of the MSNHS with multiple actuators to accommodate with time-varying load and recover potential energy. The experimental validation is conducted on the MSNHS platform by simulating a 90° truck-loading cycle of the excavator. Experimental results demonstrate that the PMS applied to the MSNHS can downsize engine input power by up to 60.27% compared with the theoretical calculation of conventional one, and then improve overall system energy efficiency.

Energy efficiency optimization of an integrated heat pipe cooling system in data center based on genetic algorithm

The energy consumption of data centers has become an increasing concern in the whole world. Actually, the cooling system consumes the most energy among the auxiliary facilities. An integrated heat pipe cooling system has been proposed to reduce the energy consumption of cooling system by using natural cooling sources in our previous work. However, it still has huge energy-saving potential in the operating process. In this paper, the heat transfer model and energy consumption model of the integrated heat pipe cooling system was established to describe the relationship between operating parameters and energy efficiency. Based on genetic algorithm, energy efficiency optimization operation strategy was calculated at different load rates and outdoor ambient temperature. An experiment was carried out to verify the accuracy of the optimization algorithm. Compared with the previous work, the energy efficiency ratio of the integrated heat pipe cooling system can be improved by 2–3 times in natural cooling model and integrated cooling mode after energy efficiency optimization. The switching rules of the system’s operating mode was studied, and analyzed the energy-saving effects of application in different climate cities.

A Switching Control Strategy Based on Switching System Model of Three-Phase VSR Under Unbalanced Grid Conditions

The power electronic converters are typical nonlinear systems. The conventional linearized modeling methods cannot accurately describe the working process of the converter. The control strategies based on the linearized model can only achieve good performance near the working point. By considering the switching nonlinear system nature of the converters, the main contributions of this article are as follows: a current error switching model is developed for the three-phase voltage source rectifiers (VSRs) under unbalanced grid for the first time; and an improved stability analysis theorem is proved for the switching control of the three-phase VSRs under unbalanced grid condition. These contributions are used to design a simple current switching controller for VSRs. The main advantages of the proposed modeling and control strategy are as follows. The switching model of the converter is built without any approximation. It accurately describes the physical working principle of the three-phase VSR under unbalanced grid condition. The proposed current switching controller has a very simple control structure. The switching states of the converter are directly produced according to the switching rule. There are no control parameters, no complicated rotation transformation, and no voltage vector modulation in the proposed switching controller. The proposed switching controller is not sensitive to the circuit parameters. The robustness of the control system is improved without any extra compensators or observers. Simulation and experiment verifies the correctness, the effectiveness, and the superiority of the proposed theory and methodology.

Finite-time H∞ output tracking control for time-delay systems with actuators failure

The problem of finite-time [Formula: see text] output tracking control for time-delay systems with actuators failure is investigated. Firstly, a switching rule and the switching regions are presented. Then, the finite-time bounded and tracking performance analysis are proposed by using Lyapunov function and average dwell time technique. Moreover, based on the switching method, a solution for controller is derived such that the resulting closed-loop system is finite-time stable. Finally, a numerical example is given to illustrate the effectiveness of the results.

Robust l2−l∞ dynamic output feedback control design for uncertain discrete‐time switched systems with random time‐varying delay

SummaryThis article deals with the problem of robust output feedback control design for a class of switched systems with uncertainties and random time‐varying delay. Our purpose is focused on designing a full order dynamic output feedback controller and an appropriate switching rule to ensure the exponential mean square stability of the resulting closed‐loop switching system with an l2−l∞ performance level. The appealing aspects of the proposed control scheme include: (a) the development of LMI based delay‐dependent sufficient conditions for the exponential stability analysis of the stochastic hybrid systems using the appropriate choice of the augmented Lyapunov–Krasovskii functional, the partitioning technique and the average dwell time, (b) conservatism reduction of the unified design conditions, and (c) the controller designed exhibiting robustness with l2−l∞ performance against uncertainties and external disturbance. Finally, representative examples are given to demonstrate the validity and the merit of the proposed design technique.

Parameterized interpolation for fusion of multidimensional signals of various resolutions

Parameterized interpolation algorithms are adapted to fusion of multidimensional signals of various resolutions. Interpolating functions, switching rules for them and local features are specified, based on which the interpolating function is selected at each point of the signal. Parameterized interpolation algorithms are optimized based on minimizing the interpolation error. The recurrent interpolator optimization scheme is considered for the situation of inaccessibility of interpolated samples at the stage of setting up the interpolation procedure. Computational experiments are carried out to study the proposed interpolators for fusion of real multidimensional signals of various types. It is experimentally confirmed that the use of parameterized interpolators allows one to increase the accuracy of signal fusion.

Extraction and analysis of brain functional statuses for early mild cognitive impairment using variational auto-encoder

Deep Auto-Encoders (DAE) have been widely used in dimensionality reduction and feature extraction of brain functional networks. However, the features in aggregation matrices of functional networks obtained by DAE dimensionality reduction might lose part of time-varying information, so that DAE cannot learn the distribution of original features well. To solve these problems, we extracted and analyzed brain functional statuses for early Mild Cognitive Impairment (eMCI) based on Variational Auto-Encoder (VAE). The high dimensions of features in aggregation matrices of dynamic functional networks were reduced by VAE to obtain the corresponding hidden variable matrices. Gaussian Mixture Model (GMM) was used to cluster the features in the hidden variable matrices to form several Common Functional Networks (CFNs) representing different functional statuses. We analyzed the similarities and differences of functional statuses between eMCI subjects and normal subjects in different sub-segments, as well as the switching of functional statuses in the entire time series. The experimental results show that there are similarities between the most frequent functional statuses of the two types of subjects and differences between the least frequent functional statuses. The proposed method can more significantly reveal the similarity and difference of functional statuses between eMCI subjects and normal subjects than the comparable methods, and the switching rule of functional statuses can help better understand the dynamic characteristics of brain functional networks for eMCI patients.

Learning-based switched reliable control of cyber-physical systems with intermittent communication faults

This study deals with reliable control problems in data-driven cyber-physical systems &#x0028 CPSs &#x009 with intermittent communication faults, where the faults may be caused by bad or broken communication devices and &#x002F or cyber attackers. To solve them, a watermark-based anomaly detector is proposed, where the faults are divided to be either detectable or undetectable. Secondly, the fault &#x02BC s intermittent characteristic is described by the average dwell-time &#x0028 ADT &#x0029 -like concept, and then the reliable control issues, under the undetectable faults to the detector, are converted into stabilization issues of switched systems. Furthermore, based on the identifier-critic-structure learning algorithm, a data-driven switched controller with a prescribed-performance-based switching law is proposed, and by the ADT approach, a tolerated fault set is given. Additionally, it is shown that the presented switching laws can improve the system performance degradation in asynchronous intervals, where the degradation is caused by the fault-maker-triggered switching rule, which is unknown for CPS operators. Finally, an illustrative example validates the proposed method.

Quantized Control for Networked Switched Systems With a More General Switching Rule

In this paper, a quantized control problem is investigated for a class of networked switched systems under the Round-Robin protocol. A more general switching rule is employed, under which the probability distribution of switching is dependent on both the sojourn time and the system mode. The Round-Robin protocol is adopted to accommodate the limitation of the network bandwidth from the viewpoint of fairness. The quantized measurement signal is sent to the controller as a feedback signal at each sampling instant. The aim of the problem addressed is to design a quantized controller such that, under the Round-Robin protocol, the switched system with the known joint distribution is mean-square stable. Considering the sojourn time and the periodicity of Round-Robin protocol, we present an interval-dependent periodic condition to guarantee the stability of addressed systems and then derive the explicit expressions of the controller for each subsystem by solving a set of matrix inequalities. Finally, a simulation example is given to demonstrate the effectiveness of the controller design method.

Adaptive finite-time output-feedback control design for switched pure-feedback nonlinear systems with average dwell time

In this paper, the issue of adaptive fuzzy tracking control is addressed for a class of completely non-affine uncertain switched pure-feedback nonlinear systems with unmeasurable states. In such a system, the average dwell time switching rule is adopted, and its stability is discussed for the first time in the sense of finite time. A fuzzy logic system-based switched observer is constructed to approximate unmeasurable states, which reduces the conservativeness stemming from utilizing a common observer for all subsystems. In addition, filter signals are applied to avoid algebraic loop problem existing in adoption of the controller. Then, a novel adaptive finite-time control strategy is developed on the basis of multiple Lyapunov functions approach, dynamic surface control and backstepping technique. It is proved that the designed controllers of subsystems can ensure that all the closed-loop signals are bounded under a class of switching signals with average dwell time, while the tracking error can converge to a small area of the origin in a finite time. Finally, two simulation examples are given to demonstrate the validity of the proposed control scheme.

Robust integral sliding mode control for uncertain switched systems under arbitrary switching rules

This article proposes a design of robust integral sliding mode control under arbitrary time-dependent switching rules for uncertain switched systems (SSs). First, a description of the control problem for the switched system is presented, after which a recursive searching method of the common Lyapunov function (CLF) for the robust stable matrix set is proposed. Based on the proposed CLF searching method, a common robust integral-type sliding mode surface is then designed, which is robust to the unmatched uncertainties. Consequently, a sliding mode controller is designed so that the system state remains on the sliding mode surface from the initial time instant. Finally, the correctness and performance of the proposed control design are verified through simulations. The controlled switched system with unmatched uncertainty in the sliding mode is robust stable under any time-dependent switching signal.

Stochastic admissibility of singular Markov jump systems with time-delay via sliding mode approach

In this article, stochastic admissibility of singular Markov jumping systems (SMJSs) with time-varying delays is studied by sliding mo de control (SMC) method. Firstly, we construct integral-type sliding mode switching functions for each Markov jump subsystem, next, we construct some linear matrix inequalities(LMI) and sufficient conditions for stochastic admissibility are given. Then the sliding mo de controller and switching rules are designed by Lyapunov stability method, the state trajectory can reach the sliding mode surface (SMS) in a limited time, resulting in stable sliding mode dynamics. Finally, two examples are given to illustrate the effectiveness and feasibility of the proposed scheme.

H∞ output tracking bumpless transfer control for switched linear systems

AbstractThis study concentrates on the problem of $H_\infty $ output tracking bumpless transfer control for a category of switched linear systems (SLSs). The $H_\infty $ output tracking bumpless transfer control problem is to ensure the SLSs to satisfy the bumpless transfer performance and the $H_\infty $ output tracking properties by co-design of a switching rule and a series of controllers. Firstly, a concept of the bumpless transfer performance for a system in this class is presented. Then, via a Lyapunov function scheme, criteria guaranteeing the bumpless transfer performance and the $H_\infty $ output tracking properties are established. The criteria allow the problem of the $H_\infty $ output tracking bumpless transfer control for subsystems is unsolvable. Finally, an example of controlling a turbofan model is offered for the verification on the effectiveness of the presented control strategy.

Reliable actuator fault control of positive switched systems with double switchings

AbstractThis paper proposes a novel double switchings reliable control for positive switched systems. Double switchings refer to the switchings of subsystems and faults. Considering the actuator faults during the system operation, a class of periodic switched actuator faults is first considered. A reliable controller is designed using linear copositive Lyapunov functions and an average dwell time switching rule is presented for the systems. Then, two average dwell time switching rules are given for the subsystems and the faults, respectively. A corresponding reliable controller is proposed in terms of linear programming. Compared with existing results, the novel approach contains three advantages: (i) the actuator faults of subsystems are allowed to be varying, (ii) two classes of detailed double switchings rules are designed, and (iii) the presented reliable control framework provides a new methodology to deal with the reliable control problem of general switched systems with faults. Finally, two examples are given to illustrate the validity of the presented results.

Global asymptotic stability of limit cycle and [formula omitted]/[formula omitted] performance of discrete-time switched affine systems

This paper treats the control design of a state-dependent switching function for discrete-time switched affine systems, assuring global asymptotic stability of a limit cycle. This limit cycle is determined according to criteria of interest related to the steady-state behaviour of the system trajectories, as for instance, its mean value, oscillation amplitude and frequency. More specifically, based on a time-varying convex Lyapunov function, a min-type switching rule is determined in order to orchestrate the state trajectories, evolving from any initial condition, towards the desired limit cycle. Most of the available methodologies are able to guide the state trajectories to a set of attraction containing the equilibrium point, assuring its practical stability. However, although important, the behaviour of the trajectories inside this set is not considered. Differently, the proposed technique assures an appropriate steady-state behaviour by adequately designing the limit cycle. Moreover, the proposed conditions take into account H2 and H∞ guaranteed costs, assuring also a suitable transient response. All the conditions are expressed in terms of linear matrix inequalities being simple to solve by readily available tools. Illustrative examples, one of them concerning the voltage regulation of a DC–DC multicellular converter, are used for validation and comparison.