线性不确定系统的给定阶最优控制器设计

为避免间接法设计降阶控制器的模型近似引起的性能下降,本文在静态输出反馈控制器设计的基础上,直接设计了线性不确定系统的给定阶混合H2/H∞动态反馈控制器.利用系统内外分解方法,得到了最优降阶状态观测器.通过求解降维状态观测器的静态输出反馈,可得到降阶控制的最优反馈增益阵.给定阶控制器由两个Ric cati方程和一个Lyapunov方程参数化表示.最后,通过一个例子,说明了本文提出的给定阶控制器设计方法.     

切换非线性系统的输出反馈周期事件触发控制

本文针对一类在任意切换信号作用下的切换非线性系统, 研究了其输出反馈周期事件触发控制问题. 所考 虑的非线性系统采用非严格反馈形式且含有未知时变控制系数. 在本文中, 仅利用采样时刻的系统输出. 为了估计 系统的不可量测的状态, 基于采样的系统输出构造了降维状态观测器. 为了减少通信资源的利用, 提出了一种新的 输出反馈周期事件触发策略, 该策略包含仅利用事件触发时刻的信息构造的输出反馈事件触发控制器以及仅在采 样时刻间歇性监测的离散事件触发机制. 通过选取可容许的采样周期及合适的公共Lyapunov函数, 证明了闭环系统 在任意切换下全局渐近稳定. 最后, 通过将本文中所给出的控制方案应用到数值算例中验证了其有效性.     

一类线性切换系统的事件触发输出调节问题

通过设计事件触发状态反馈控制器,研究一类线性切换系统的输出调节问题.相比于时间触发控制,事件触发控制可显著地降低控制任务执行的次数.由于事件触发时刻与切换时刻的相互混合,导致切换系统控制器的设计十分困难.本文通过给出事件触发机制、状态反馈控制器和满足平均驻留时间的切换信号联合设计的方案,得到系统输出调节问题可解的充分条件.非共同坐标变换突破原有各子系统的调节器方程组具有共同解的限制.此外,为了避免Zeno现象,给出相邻事件触发间隔时间存在一个正下界.最后,应用切换RLC电路系统进行仿真验证结论的有效性.     

反馈控制器降阶的约束与聚集方法

根据线性随机系统的包含原理,研究系统状态反馈和输出反馈控制器的降阶问题,给出了系统控制器降阶的约束和聚集两类条件。以一个18阶系统降阶反馈控制器的设计为例,说明该方法既简化了控制器的结构,又不失全阶控制器的主要性能。     

不确定广义系统的降阶H-infinity控制器设计

研究基于函数观测器的不确定广义系统的降阶H-infinity控制器设计问题. 首先提出了基于严格线性矩阵不等式的不确定广义系统H-infinity控制的充分条件, 并用于状态反馈H-infinity控制设计. 然后对所得控制增益进行降阶观测, 基于广义Sylvester矩阵方程的显式通解, 考虑系统的H-infinity性能约束, 提出了降阶输出反馈控制器的参数化设计方法.     

基于降阶卡尔曼滤波器的水下机器人滑模容错控制

针对水下机器人执行器时变、非线性故障,提出一种基于降阶卡尔曼滤波器的故障估计和滑模容错控制方法.用降阶卡尔曼滤波器估计水下机器人故障解耦子系统的状态,受故障的影响,子系统状态可测.由估计的状态和测量的状态可进一步得到水下机器人执行器的故障信息.滑模容错控制器根据所估计的执行器故障调整控制器的输出以实现容错控制.仿真结果验证了所提出的故障辨识与容错控制算法的有效性.     

不确定广义系统的降阶H∞控制器设计

研究基于函数观测器的不确定广义系统的降阶H∞控制器设计问题.首先提出了基于严格线性矩阵不等式的不确定广义系统H∞控制的充分条件,并用于状态反馈H∞控制设计.然后对所得控制增益进行降阶观测,基于广义Sylvester矩阵方程的显式通解,考虑系统的H∞性能约束,提出了降阶输出反馈控制器的参数化设计方法.     

一类非线性切换系统任意切换采样控制设计

本文针对一类具有非严格反馈形式的非线性切换系统,在输出只在采样点可获得的情况下,提出了一种基于模糊采样观测器的自适应输出反馈控制方法.该方法降低了现有任意切换控制研究结果中因共同控制思想导致的控制器设计的保守性,避免了迭代过程对虚拟控制的反复求导引发的计算爆炸现象及控制器高增益的弊端.切换的自适应律突显了每个子系统的特性,建立的采样控制器节约了信息传输资源.共同Lyapunov函数理论确保了相应闭环切换系统所有变量在任意切换信号下的一致有界性.     

一类控制问题的降阶控制器设计

基于线性矩阵不等式(LMI,1inear matrix inequalities),考虑了线性时不变对象的一类 控制问题的降阶控制器设计问题.给出了一个新的降阶控制器阶的上界,该上界适用于标准和 奇异控制两种情形.证明是构造性的,可以给出降阶控制器的构造方法.给出了简单的例子,说 明该方法的可行性和正确性.     

切换系统的无扰切换控制及其在航空发动机中的应用

利用多Lyapunov函数方法, 本文研究了一类切换线性系统的状态跟踪无扰切换控制问题.首先, 刻画了控制信号在切换时刻处的抖振抑制水平.其次, 通过控制器与切换律的同时设计, 实现了系统的状态跟踪和控制信号抖振抑制.最后, 将所提出的状态跟踪无扰切换控制策略应用于一个涡扇航空发动机模型的控制设计上, 说明了所提出方法的有效性.     

异步切换多智能体系统的协同输出调节

研究了一类控制器模态和系统模态不匹配的异步切换多智能体系统的输出调节问题.利用平均驻留时间和联合切换信号相结合的方法来处理由控制器与系统模态的切换存在时延引起的系统不稳定问题.提出一种基于输出反馈的切换控制策略,给出了异步切换多智能体输出调节问题可解的充分条件.最后,通过仿真实例验证结果的有效性.     

Robust Output Feedback Stabilization of Switched Nonlinear Systems with Average Dwell Time

For some switched nonlinear systems, stabilization can be achieved under arbitrary switching with state feedback control. Due to switching zero dynamics, output feedback stabilization for some switched nonlinear systems needs dwell time between switching to guarantee system stability. In this paper, we consider a class of switched nonlinear systems with unknown parameters and unknown switching signals. We design a robust output feedback controller that stabilizes the system under a class of switching signals with average dwell time (ADT) where the value of ADT can be reduced by adjusting the control gain. For some special cases, common quadratic Lyapunov functions of the closed‐loop systems can be found and the value of ADT is further relaxed. Some examples and simulations are provided to validate the results.     

多时滞离散切换系统的动态输出反馈H∞控制

借助多Lyapunov函数方法,研究一类具有多时滞的离散切换系统的鲁棒[H∞]控制问题。假设切换系统的每个子系统都不能实现鲁棒[H∞]控制,基于切换动态输出反馈控制策略,给出了系统存在鲁棒[H∞]干扰抑制水平[γ]可切换镇定的充分条件,并表示成与时滞相关的线性矩阵不等式（LMI）形式,还分别给出了切换律和动态输出反馈控制器的设计方案。最后用仿真例子说明了结论的有效性。     

Neural networks stabilization and disturbance attenuation for nonlinear switched impulsive systems

In this paper, we address the problem of neural networks (NNs) stabilization and disturbance rejection for a class of nonlinear switched impulsive systems. An adaptive NN feedback control scheme and an impulsive controller for output tracking error disturbance attenuation of nonlinear switched impulsive systems are given under all admissible switched strategy based on NN. The NN is used to compensate for the nonlinear uncertainties of switched impulsive systems, and the approximation error of NN is introduced to the adaptive law in order to improve the tracking attenuation quality of the switched impulsive systems. Impulsive controller is designed to attenuate effect of switching impulse. Under all admissible switching law, impulsive controller and adaptive NN feedback controller can guarantee asymptotic stability of tracking error and improve disturbance attenuation level of tracking error for the overall nonlinear switched impulsive system. Finally, a numerical example is given to demonstrate the effectiveness of the proposed control and stabilization methods.     

Stabilization of Enforced Positive Switched Linear Systems with Bounded Controls

This paper is concerned with the controller synthesis issue for enforced positive switched linear systems via output feedback. First, the stabilization problem is studied with output feedback under average dwell time switching signal, and the controllers we proposed guarantee stability and positivity of the closed-loop systems. Second, the output feedback stabilization issue is investigated by introducing special form of diagonal matrices, and the constraints on states and control inputs are solved based on limited initial conditions. Then, the derived conditions are described via linear programming, also extending the theoretical findings to constrained output issue. Finally, the simulation results demonstrate the feasibility of the control strategy.

     

Finite-time output feedback stabilisation of chained-form systems with inputs saturation

This paper investigates the problem of finite-time stabilisation by output feedback for a class of non-holonomic systems in chained form with input saturation. Rigorous design procedure for saturated output feedback control is presented by using the homogeneous domination approach and the nested saturation technique. Together with a novel switching control strategy, the designed controller renders that the states of closed-loop system are regulated to zero in a finite time. A simulation example is provided to illustrate the effectiveness of the proposed approach.     

Operating regime-based controller strategy for multi-product processes

A hybrid, dynamical supervisory control strategy is introduced to control multi-product processes. The scheme involves the selection of the best setpoint controller, from an existing family of feedback controllers, to be placed into feedback with the process so as to cause the output to track the desired setpoint. This task is performed without exhaustive trial and error, by minimizing a specific normed output estimation error that relates the process output to a shared controller state. The performance of the supervisory control strategy is demonstrated on a continuous-stirred tank reactor that can be operated at three different conversion levels. However, the most desirable operating point is open-loop unstable. Linear controllers are designed for each operating region and the role of the supervisory control strategy will be to determine the switching logic as different scheduling policies are demanded.     

Adaptive output feedback control for nonholonomic systems with uncertain chained form

The output feedback adaptive control problem is investigated for nonholonomic systems with strongly nonlinear uncertainties and unknown virtual control directions. A nonlinear output feedback switching controller based on the output measurement of the first subsystem is employed in order to make the state scaling effective and ensure the convergence of the system states. The novel observer/estimator is introduced for state and unknown parameter estimates. The integrator backstepping technique by the use of a constructive recursive is applied to the design of the adaptive controller and to overcome the unknown virtual control directions. The simulation result validates the effectiveness of the proposed scheme.     

Output feedback stabilization for nonholonomic systems with unknown unmeasured states‐dependent growth

This paper is concerned with the global output feedback stabilization for a class of nonholonomic systems with unknown parameter, polynomial‐of‐output, and unmeasurable states dependent growth. A dynamic high‐gain observer is first designed to reconstruct the unmeasurable system states and, in addition, to compensate the serious parameter unknowns in nonlinear drifts. Then, we design a compact adaptive controller without invoking the backstepping technique, which reduces the complexity of controller. Additionally, a switching control strategy is employed to overcome the smooth feedback obstacle associated with nonholonomic systems. It is shown that the proposed control laws guarantee that all closed‐loop system states are globally bounded and ultimately converge to zero. The simulation results demonstrate the effectiveness of the proposed control strategy.     

Adaptive Control of Piecewise Linear Systems with State Feedback for Output Tracking

A piecewise linear system consists of a set of linear time‐invariant (LTI) subsystems, with a switching sequence specifying an active subsystem at each time instant. This paper studies the adaptive control problem of single‐input, single‐output (SISO) piecewise linear systems. By employing the knowledge of the time instant indicator functions of system parameter switches, a new controller structure parametrization is proposed for the development of a stable adaptive control scheme with reduced modeling error in the estimation error signal used for parameter adaptive laws. This key feature is achieved by the new control scheme's ability to avoid a major parameter swapping term in the error model, with the help of indicator functions whose knowledge is available in many applications. A direct state feedback model reference adaptive control (MRAC) scheme is presented for such systems to achieve closed‐loop signal boundedness and small output tracking error in the mean square sense, under the usual slow system parameter switching condition. Simulation results on linearized NASA GTM models are presented to demonstrate the effectiveness of the proposed scheme.