具有饱和执行器的不确定时滞系统的鲁棒稳定性

本文研究了一类具有饱和执行器的不确定时滞系统的鲁棒镇定问题，所考虑的系统具有时变未知有界的不确定参数和状态滞后，基于系统的线性矩阵不等式给出了系统可鲁棒镇定的判据以及鲁棒无记忆状态反馈控制规律。     

Finite-time Feedback Stabilization of a Class of Input-delay Systems With Saturating Actuators via Digital Control

In this paper, the problem of making an input-delay system with saturating actuators finite-time stable by virtue of digital control is investigated. A digital state feedback controller and digital observer-controller compensator are designed for two cases: when the state of the input-delay system are available or when it is unavailable. Sufficient conditions which guarantee finite-time stability of a closed-loop input-delay system are given and the proof procedure is presented in a heuristic way by constructing appropriate comparison functions. The condition can be transformed into the intersection of two curves satisfying some constraints, which reveals the relationship between designed parameters clearly. Finally, simulation results are presented to validate the method proposed in this paper.      

Robust Stabilization Of Interval Plants With Constant Disturbance

The aim of this brief paper is to study the output feedback, robust stabilization problem for a class of SISO interval plants with unknown constant disturbance. For interval plants of minimum phase and known high‐frequency gain, it shows that a simple controller with integral action is able to reject the disturbance. A procedure to compute the parameters of the controller is discussed.     

Robust Control for a Class of Uncertain Switched Fuzzy Systems with Saturating Actuators

This paper investigates the robust control problem for a class of uncertain switched fuzzy systems with saturating actuators. The asymptotical stability for fuzzy subsystems subject to actuator saturation is not assumed. Based on the multiple Lyapunov functions method, we design a switching law and a state feedback control law such that the closed‐loop system is asymptotically stable. Additionally, the estimation of the domain of attraction is presented by solving an optimization problem. Finally, simulation results verify the feasibility and effectiveness of the proposed method.     

Root Locus for Random Reference Tracking in Systems With Saturating Actuators

This paper develops a root locus technique for random reference tracking in systems with saturating actuators. This is accomplished by introducing the notion of S-poles, which are the poles of the quasilinear system obtained by applying the method of stochastic linearization to the original system with saturation. The path traced by the S-poles on the complex plane when the gain of the controller changes from 0 to infin is the S-root locus. We show that the S-root locus is a subset of the standard root locus, which may terminate prematurely in the so-called termination points. A method for calculating these points is presented and a number of other, more subtle, differences between the usual and the S-root loci are described. In addition, the issue of amplitude truncation in terms of the S-root locus is investigated. Finally, an application of the S-root locus to hard disk drive controller design is presented.     

一类具有非线性饱和执行器的不确定时滞系统鲁棒控制

研究一类具有非线笥饱和执行器朱确定线性时滞系统的鲁棒性镇定问题。所考虑的不确定时滞系统具有时变未知且有界的不确定参数和状态时滞。提出了新的鲁棒可镇定判据和相应的鲁棒无记忆状态反馈控制器设计方法。数值仿真例子说明了所提出方法的有效性。     

A Sub-Optimal Second Order Sliding Mode Controller for Systems With Saturating Actuators

In this technical note, the problem of the possible saturation of the continuous control variable in the sub-optimal second order sliding mode controller, applied to systems with saturating actuators, is addressed. It is proved that during the sliding phase, if basic assumptions are made, the continuous control variable never saturates. On the contrary, during the reaching phase, the presence of saturating actuators can make the steering of the sliding variable to zero in a finite time not always guaranteed. In the present technical note, the original algorithm is modified in order to solve this problem: a new strategy is proposed, which proves to be able to steer the sliding variable to zero in a finite time in spite of the presence of saturating actuators.      

具有滞后输入的不确定系统的鲁棒镇定

本文研究具有滞后输入的不确定系统的鲁棒镇定问题，导出了系统可以用一个无记忆状态反馈控制律鲁棒镇定的条件，据此，提出了一个鲁棒稳定化控制器的设计方法．     

具有补偿器的菱形对象族的鲁棒稳定性

本文给出了具有补偿器的菱形对象族鲁棒稳定的充分必要条件。本文的方法和结论可用来研究菱形对象族的其它鲁棒问题，还可为补偿器的设计提供有益的方法。     

An Interpolation Technique for Input Constrained Robust Stabilization

This paper presents an interpolation technique of two given robust stabilizing gains for input constrained uncertain systems. The proposed interpolated feedback gain is computed at every sampling instance by solving an optimization problem with a single decision variable. Use of the interpolated feedback gain can bring about not only large invariant set but also good control performance. Moreover, it is shown that the feasible and invariant set yielded by the proposed control is the convex hull of the two invariant sets by the known controls. The simulation results show that the proposed interpolation based feedback gain indeed results in both large invariant set and good control performance.     

Simultaneous External and Internal Stabilization for Continuous and Discrete-Time Critically Unstable Linear Systems with Saturating Actuators

The issues arising in hybrid or simultaneous external as well as internal stabilization of linear systems with saturating actuators are considered. Four different stabilization problems are studied. Roughly, these problems are (1) simultaneous semi-global external as well as semi-global internal stabilization, (2) simultaneous semi-global external as well as global internal stabilization, (3) simultaneous global external as well as semi-global internal stabilization, and (4) simultaneous global external as well as global internal stabilization. As evident from the literature, the requirement of internal stabilization alone either in the global or semi-global sense demands that the linear part of the given system be (a) stabilizable, and (b) has all its poles in the closed left half complex plane for continuous-time systems while it has all its poles inside and/or on the unit circle for discrete-time systems. This implies that the posed simultaneous stabilization problems are solvable at best only under the conditions (a) and (b). Under such conditions, we construct here explicit state as well as measurement feedback controllers for all the four problems in the case of continuous-time systems, and for the problems (1), (2) and (4) in the case of discrete-time systems. The design methodologies used to construct appropriate feedback laws are based on by now familiar low-gain and low-and-high gain design concepts or certain scheduled versions of them.     

菱形对象族的顶点镇定结果

本文研究了菱形对象族的鲁棒镇定问题。当控制器取为分子，分母为仅有奇次项的或仅有偶次荐的多项式的真有理分式时，证明了该控制器鲁棒镇定菱形对象族的充分必要条件为该控制器同时镇定三十二个顶点对象。当上述控制器的分子，分母限于正负交错系数的仅有奇次项的或仅有偶次项的多项式时，该控制器鲁棒镇定菱形对象族所需同时镇定的顶点对象最多为十六个，所进结果与对象族的阶次无关。     

鲁棒镇定区间系统族的一个充分条件

讨论了区间系统族的鲁棒镇定问题,给出存在控制器鲁棒镇定区间系统族的一个充分条件,并且当这个条件成立时,得到了鲁棒镇定区间系统族的控制器的参数化公式.     

具有饱和输入的预测控制的稳定性分析

本文对具有干扰，扇形饱和输入及其线性未建模动太民的预测控制进行综合设计。     

具有多输入时滞的不确定广义系统的时滞相关鲁棒镇定

研究具有多输入时滞及参数不确定性的广义系统的时滞相关鲁棒镇定问题. 首先利用LMI给出相应的标称系统的时滞相关镇定准则. 然后, 基于这个准则, 设计状态反馈控制器, 使得对任何允许的不确定参数相应的闭环系统是正则, 稳定, 无脉冲的. 最后的数值算例表明所提方法是有效的.     

Global Asymptotic Stabilization of a Spinning Top With Torque Actuators Using Stereographic Projection

The dynamical equations for a spinning top are derived in which theorientation is specified by a complex variable using stereographic projectionof Poisson's equations. Necessary and sufficient conditions for Lyapunovstability of the uncontrolled motion of the spinning top are derived usingthe Energy-Casimir method. Control laws that globally asymptoticallystabilize the spinning top to the sleeping motion using two torque actuatorsare synthesized by employing techniques from the theory of systems in cascadeform and generalized using Hamilton-Jacobi-Bellman theory with zero dynamics.In short, this paper provides a nice example where the interplay betweendynamics and control leads to elegant and powerful results.     

针对输入时滞的桥式起重机鲁棒控制

针对工业桥式起重机输入信号存在时滞的问题,本文设计了一种鲁棒跟踪控制器.具体而言,本文通过分析欠驱动桥式起重机的特性,引入辅助系统,将时滞模型等效为不存在时滞的模型.在此基础上,考虑系统参数的不确定性,设计了一种鲁棒跟踪控制器.本文使用基于Lyapunov理论的稳定性分析及证明方法,通过建立Lyapunov-Krasovskii（LK）方程证明了位置跟踪误差以及摆角可以在有限时间内收敛到一个界内,且界的大小与控制增益负相关.完成控制器设计后,将其与工业上常用的比例-积分-微分（Proportion-integration-differentiation,PID）控制方法进行比较.仿真及实验结果表明,本文所设计的控制器优于PID控制器,具有良好的控制性能.     

Finite-Time Stabilization of Linear Systems With Input Constraints by Event-Triggered Control

<正>Dear editor,This letter designs the event-triggered control(ETC) to achieve finite-time stabilization(FTS) of linear systems with input constraints. The key idea of the established algorithm is that the designed time-varying high-gain is only scheduled on a specified time determined by an event-triggered mechanism.     

Robust State Feedback Control Through Actuators With Generalized Sector Nonlinearities And Saturation

In control systems, actuators often have nonlinear characteristics that can not be neglected. For linear systems driven by actuators satisfying the generalized sector condition, a robust state feedback controller synthesis method is proposed to achieve the ultimate boundedness control. The method is based on the linear matrix inequality approach and is easy to apply. As an important special case of the generalized sector condition, the saturation characteristic of actuators is discussed separately, and non‐conservative results are obtained.