一类复杂系统的自适应控制

对于具有相似性的一类不确定复杂系统,应用高阶神经网络逼近各个子系统的互联项,设计了控制器,即提出了难以解决的互联项问题的高阶神经网络表示方法．该方法通过在线调节神经网络的权值来确保闭环系统的稳定性．由于复杂系统的结构相似性,降低了控制器设计过程中的计算量,使得工程上较易实现．仿真算例表明了所提出方法的有效性.     

一类具有相似结构的不确定非线性广义互联系统的鲁棒控制

研究一类具有非线性互联作用的广义互联系统,在其互联项中含有不确定性。以前人对广义系统和相似性的研究为基础,定义了这类系统的相似结构,提出了新的相似性概念,对系统设计鲁棒控制器。由于控制本身也具有相似结构,因此易于工程实现。     

一类相似广义互联系统的异数—输出反馈鲁棒控制器设计

以广义系统中受限系统等价概念和导数反馈－输出反馈为基础,定义了一类广义互联系统的相似结构,提出了相似性研究的新方向。这类系统具有不满足匹配条件的非线性不确定互联项。设计了导致一输出反馈鲁棒分散控制器,使互联系统在平衡点处渐近稳定,由于控制器本身也具有相似结构,因此易于工程实现。     

一类复杂系统的容错控制

研究一类互联系统的容错H∞控制问题，提出了具有相似性的容错控制器的设计方法．当所有执行器正常时，可保证闭环系统稳定和H∞性能；当一些执行器失效时，仍能保证闭环系统稳定和H∞性能，仿真算例证明了该方法的有效性。     

非线性互联系统的分散混合自适应智能控制

针对一类高阶互联MIMO非线性系统，利用TS模糊系统和神经网络的通用逼近能力，在神经网络控制器中引入模糊基函数，提出一种分散混合自适应智能控制器设计的新方案．基于等价控制思想，设计分散自适应控制器，无需计算TS模型．通过对不确定项进行自适应估计，取消了其存在已知上界的假设．通过理论分析，证明了闭环智能控制系统所有信号有界，跟踪误差收敛到零．     

基于高次神经网络的一类非线性组合大系统的鲁棒控制器设计

对于一类非线性组合大系统,本文提出了基于 高次神经网络的一种新型控制器的设计方法．本文首先用高次神经网络逼近非线性组合大系 统中的互联项,然后基于高次神经网络设计一种新型控制器,这种设计方法不仅解决了大系 统中的最为复杂的互联项问题,较以往采用的办法在工程上易于实现．仿真结果表明了该方 法的有效性．     

一类切换模糊时滞组合系统的分散镇定

提出了切换模糊时滞组合系统模型,并研究了状态和互联项具有时滞情况下的分散镇定问题.当每个互联子系统中的每个切换子系统具有有限个备选的状态反馈控制器,且单一控制器均不能保证系统稳定的情况下,利用多Lyapunov函数方法给出了时滞相关的矩阵不等式条件和分散切换律设计方法,使系统在所提出的分散切换律和分散控制器下渐近稳定.仿真结果表明了所提出方法的有效性.     

时滞不确定组合系统的鲁棒分散输出控制

讨论了时滞不确定组合系统的鲁棒分散输出控制问题．不确定项存在于子系统内部,可以是非线性或时交的：而且时滞存在互联项中,并满足匹配条件．不确定项是有界的,但界是未知的．利用自适应律来估计未知的上界,设计出分散无记忆输出控制器．基于Lyapunov稳定性理论和Lyapunov-Krasovskii函数,该控制器能够保证闭环系统的解是终极一致有界的．最后的仿真结果说明该设计方法是有效的．     

一类互联机器人系统的鲁棒分散跟踪控制

研究互联机器人系统在受到模型不确定性和外部干扰情况下的鲁棒轨迹跟踪问题.针对系统中存在的不确定动力学问题,在不确定项的连续界函数已知的情况下,基于Lyapunov设计方法提出一种鲁棒分散控制器的设计方法,实现互联机器人系统位置和速度的渐近跟踪.仿真算例表明了该方法的有效性.     

一类相似广义互联系统的导数-输出反馈鲁棒控制器设计

以广义系统中受限系统等价概念和导数反馈- 输出反馈为基础,定义了一类广义互联系统的相似结构,提出了相似性研究的新方向.这类系 统具有不满足匹配条件的非线性不确定互联项.设计了导数-输出反馈鲁棒分散控制器,使互 联系统在平衡点处渐近稳定.由于控制器本身也具有相似结构,因此易于工程实现.     

Risk assessment in control of fractional-order coronary artery system in the presence of external disturbance with different proposed controllers

In this study, different controllers for control of fractional-order coronary artery system in the presence of external disturbance are designed. Using sliding mode, the proposed type 1 and type 2 fuzzy methods, the suitable controllers are proposed. In sliding mode control, a fractional sliding surface is presented and the control signal is modified to prevent chattering in the control system. With mathematical analysis, a type of membership function is suggested which has better performance in the fractional order system. Also, a rule-base is presented which leads to better results in type 1 and type 2 fuzzy controllers. The risk of the proposed controllers in different conditions is analyzed. Finally, according to the other analyzing methods, it is shown that this analyzing method has more accurate results.     

安全的混成系统神经网络控制器生成与验证

控制器生成是混成系统控制中的重要问题.生成具有安全保证的控制器,关系着混成系统在安全攸关领域的使用.提出了一种为混成系统生成具有安全保证的神经网络控制器的方法.神经网络控制器的安全性由与其同时生成的障碍证书保证.为了生成安全的神经网络控制器,首先确定控制器的网络结构,并基于混成系统构造训练数据集;然后,根据保证控制器安全的障碍证书条件编码神经网络训练时的损失函数.当训练完成后,学习到的神经网络控制器对于训练数据集中的数据是安全的,但对于整个混成系统可能并不安全.为了检验学习到的控制器在整个系统上的安全性,将其安全验证问题转化为一组混合整数规划问题,并使用数值优化器求解,以得到形式化保证的结果.工作实现了安全神经网络控制器生成工具SafeNC,并评估了它在8个基准系统上的性能.实验结果表明:SafeNC可以生成包含6个隐藏层的具有1 804个神经元的安全神经网络控制器;同时,与现有方法相比, SafeNC可为更复杂的系统生成安全的神经网络控制器,更有效且更具扩展性.     

Energy-based robust controller design for flexible spacecraft

This paper presents a class of non-model2based position controllers for a kind of flexible spacecraft. With the controllers, one can achieve not only the closed-loop stability of the original distributed parameter system, but also the asymptotic stability of the truncated system, which is obtained through representing the deflection of the appendage by an arbitrary finite number of flexible modes. The system dynamics are not explicitly involved in the controller design and stability proof. Instead, only a very basic system energy rehtionship of the flexible spacecraft is utilized. The controllers possess several remarkable advantages over the traditional model-based ones. Numerical simulations are carried out on a kind of spacecraft with one flexible appendage and satisfactory results are obtained.     

单级倒立摆的PID控制研究

对单级倒立摆系统的平衡控制问题进行了研究，分别采用PD，PI和PID三种方案实现了单级倒立摆系统的平衡控制。首先，建立系统的数学模型，然后通过仿真实验设计并整定各方案的控制器参数，将所设计的控制器分别在实际的物理设备上进行实时控制实验，都成功地实现了倒立摆的平衡控制。实际控制结果验证了各方案的正确性和有效性。     

Chen混沌系统的模糊控制

由于T-S模糊模型可以精确地逼近一类仿射非线性系统,所以可以用T-S模糊模型来逼近Chen混沌系统,并应用模糊系统的控制理论求得模糊控制器,以达到良好的控制效果.基于此方法并用并行分散补偿(PDC)方法设计了两个控制器来镇定Chen混沌系统,其中第一个控制器的条件比较保守,第二个控制器的条件在第一个条件的基础上作了改进,得到具有较少保守性的镇定性条件.控制器的所有参数可以通过求解一组线性矩阵不等式得到.用MATLAB仿真的结果显示了PDC控制方法的良好的控制效果.     

基于直接反馈线性化理论的微机非线性励磁控制器

应用直接反馈线性化（ＤＦＬ）理论，为发电机励磁系统设计了非线性控制器，该控制器已在平度热电厂投入实际运行，为本文研制的励磁控制器的提供了具说服力的实例。     

Stability and stabilization of switched stochastic systems under asynchronous switching

This paper studies the stability and stabilization problems for a class of switched stochastic systems under asynchronous switching. The asynchronous switching refers to that the switching of the candidate controllers does not coincide with the switching of system modes. Two situations are considered: (1) time-delayed switching situation, that is, the switching of the candidate controllers has a lag to the switching of the system modes; (2) mismatched switching situation, the switching of the candidate controllers does not match the switching of the system modes. Using average dwell time and Lyapunov-like function, sufficient conditions are established for stochastic input-to-state stability of the whole system. Also, the stabilizing controller design approach is proposed for switched stochastic linear systems. The minimal average dwell time and the controller gain are achieved. Finally, a numerical example is used to demonstrate the validity of the developed results.     

ZD Method Based Nonlinear and Robust Control of Agitator Tank

To improve industrial efficiency, an agitator tank system should have not only a short response time, but also produce reagents with accurate concentration and moderate liquid level. This paper presents a new method called Zhang dynamics (ZD) to perform tracking control, that is, to make the concentration and liquid level of the agitator tank converge to the desired trajectories. Two controllers for tracking control of an agitator tank system are designed based on ZD method. In addition, the robustness of the agitator tank system equipped with ZD controllers is investigated. Theoretical analyses on the convergence performance and robustness of the agitator tank system equipped with ZD controllers are presented. To substantiate the effectiveness of the ZD method for tracking control of the agitator tank system, we perform simulations on three different groups of tracking trajectories, which reflects the corresponding application conditions in the chemical industry. To test the robustness of the agitator tank system equipped with ZD controllers, additional simulations with different disturbances added in the agitator tank system and the ZD controllers are performed. Simulation results validate the feasibility and effectiveness of the ZD method for tracking control of the agitator tank system.     

PD–PID controller for delayed systems with two unstable poles: a frequency domain approach

This paper deals with the stability problem of linear delayed systems containing two unstable real poles by means of PD controllers. The analysis presented is based on frequency domain techniques. Necessary and sufficient conditions for the existence of stabilising controllers are given in terms of the parameters of the system and the time delay size. The main result is extended to delayed systems with two unstable poles and n stable real poles. PID controllers are also considered in order to control the studied systems, obtaining similar stability conditions. Numerical examples are presented in order to illustrate the control performance.     

Coordinated circumnavigation by multiple agents under directed topology

ABSTRACT

This paper focuses on the coordinated circumnavigation problem for multiple agents with directed communication topology. All agents are required to be evenly spaced around a moving target, and orbit around it with prescribed radii and circular velocity. We divide the coordinated circumnavigation system into a cascaded system consisting of a standoff tracking subsystem and a spacing distribution subsystem. A tracking controller and an additional controller for the two subsystems are developed, respectively. The global uniform stability of the coordinated circumnavigation system is analysed using the cascaded control theory. The presented controllers render each individual agent circumnavigating the target with the desired requirements. More importantly, we show that the derived tracking controller is a general extension of existing controllers for single agent circumnavigation problem. Another feature of the proposed controllers is that the directed topology considered only needs to have a directed spanning tree. Furthermore, the proposed controllers take the velocity constraints into consideration, that is more rational for practical applications. Numerical simulations are provided to verify the effectiveness of the proposed methods.