低增益变结构模型参考自适应控制器设计

就对象相对阶大于1时的变结构模型参考自适应控制（VS－MRAC）系统提出了一种低增益变结构控制方案,主要特点是：1）系统变结构律在低增益状态下仍可保证所有辅助误差在有限时间内收敛到零,从而提高了系统跟踪精度;2）进一步研究了平均值滤波器对系统稳定性的影响。     

一类非线性系统的积分变结构模糊自适应跟踪控制

针对一类具有未知常数控制增益的不确定非线性系统,基于变结构控制原理,并利用具有非线性可调参数的模糊系统逼近等价控制,提出一种具有监督控制器的积分变结构模糊自适应跟踪控制策略.该策略通过监督控制器保证闭环系统所有信号有界.进一步,通过引入最优逼近误差的自适应补偿项来消除建模误差的影响.理论分析证明了跟踪误差能够收敛到零.仿真结果表明了该方法的有效性.     

含有不灵敏区非线性系统的增益调度自适应变结构控制

针对具有控制输入不灵敏区及有界不确定性的非线性系统,采用增益调度变结构控制策略,研究其镇定问题.利用增益调度策略和自适应参数估计方法,在同时存在参数、结构及干扰的不确定性和未知控制输入不灵敏区的情形下,提出了新的增益调度自适应变结构镇定控制律设计方法,既节省了控制能量,又消除了控制信号的颤振.所提出的控制律可以保证闭环输出为一致终结有界,并且算法比较简单,便于实现.用数字仿真方法验证了所得控制律设计方法的有效性.     

机械手的高精度轨迹跟踪控制研究

本文针对机械手的高精度轨迹跟踪控制问题进行了研究.首先通过一个典型的 SISO 系统用频域分析说明了当采用变结构控制时,只要系统高频未建模部分的相位滞后超过—π/2,就必须引入边界层的结论.然后在此基础上给出了确定一般机械手的对轨迹跟踪精度起决定性作用的回路最高反馈增益的条件.本文同时给出了一种简单实用的动力学参数离线估计方法.最后通过实验给出了高精度控制的结果.     

鲁棒变结构模型参考自适应控制器的分析与设计(Ⅱ)

对含未建模动态且建模部分相对阶大于 1(n >1) 的SISO定常线性系统提出了一种控制增益可切换的变结构模型参考自适应控制方案 .主要结果是 :得到了系统跟踪误差与辅助误差间关系的明确表达式 ,进而证明 ,对各辅助子系统 (均为相对阶为 1的子系统 ) ,只要按相对阶为 1时所提出的变结构律进行设计 ,使它们满足预先给定的性能指标 ,就可保证系统跟踪误差在预先给定的过渡过程时间内收敛到一个残集内 ;研究结果还表明 ,当n >1时 ,平均值滤波器对系统的影响相当于一个未建模动态对系统的影响     

基于LPF的加权积分型增益变结构控制器

将低通滤波器与变结构控制器相结合,即在变结构控制器的输出端加上低通滤波器(LPF),可以有效地滤除控制对象输入信号中的高频抖振,从而得到较好的控制效果.针对低通滤波器与常规变结构控制器结合时系统初始段跟踪精度不高及整体抗干扰能力不强的缺点,本文提出了基于低通滤波器的分段变结构控制,即根据误差的分布范围分别采用常规的变结构控制器或加权积分型增益变结构控制器.论文最后利用MATLAB对系统进行仿真,结果表明该控制方法可提高系统的抗干扰能力.     

基于Nussbaum增益滑模自适应控制的 导弹制导控制一体化设计

采用Nussbaum增益滑模自适应控制方法解决导弹制导控制一体化设计问题. 充分考虑一体化模型具有通道间耦合、气动建模不确定性、气动参数摄动和目标机动引起的干扰等特点, 基于自适应控制对未知量的辨识能力和滑模控制的抗干扰能力, 以及Nussbaum增益控制对系数不确定系统所具有的较好的控制能力, 设计Nussbaum增益滑模自适应控制律, 并证明系统的稳定性. 仿真结果验证了所提出方法的有效性.     

一种新型的滑模变结构增益调度控制器设计方法

研究影响一般滑动模态变结构控制性能的因素,并给出了根据切换函数选择滑动模态系数、边界层厚度以及控制器增益系数的一般要求．针对一类含参数不确定性的非线性系统,采用新型增益调度变结构控制策略进行控制,以切换函数作为调度变量对滑动模态系数、边界层厚度以及控制器增益系数进行调度,以提高滑动模态变结构控制系统的控制性能,抑制颤振,降低控制能耗．仿真算例验证了所提出控制策略的有效性．     

降低鲁棒变结构模型参考自适应稳态控制增益的模糊实时分层方法

提出一种模糊实时分层方法来降低鲁棒变结构模型参考自适应稳态控制增益。利用模糊理论将一些定性经验与已提出的鲁棒变结构模型参考自适应控制相结合,可以在一定程度上克服稳态控制增益高的缺点。仿真结果表明,采用模糊实时分层方法后,稳态控制增益有所降低。     

鲁棒变结构模型参考自适应控制器的分析与设计(Ⅰ)

对含有未建动态ＳＩＳＯ定常线性系统提出了一种控制增益可切换的变结构模型参考自适应控制方案。其主要结果是：解决了当对象建模部分相对阶为１、高频增益符号未知时,确保跟踪误差满足预先给定的过渡过程性能指标（超调量,过渡时间和稳态误差）的问题。     

Realization of online optimizing control in an industrial semi-batch polymerization

In this work, the realization of an online optimizing control scheme for an industrial semi-batch polymerization reactor is discussed in detail. The goal of the work is the automatic minimization of the duration of the batch without violating the tight constraints for the product specification which translate into stringent temperature control requirements for a highly exothermic reaction. Crucial factors for a successful industrial implementation of the control scheme are the development and the validation of a process model that is suitable for process optimization purposes and the estimation of unmeasured process states and the online compensation of model uncertainties. Two implementations are proposed, a direct online optimizing control scheme and a simplified scheme that combines a model-predictive temperature controller and a monomer feed controller that steers the cooling power to a predefined value in a cascaded fashion. We show by simulation results with a validated process model that both schemes achieve the goals of tight temperature control and reduction of the batch time. The performance of the NMPC controller is superior, on the other hand the cascaded scheme could be directly implemented into the DCS of the plant and is in daily operation while the online optimizing scheme requires an additional computer and is currently in the test phase.     

A model reference robust control with application to a flight control system design

In this paper, a new model reference robust control scheme for plants with relative degree greater than one is proposed for the purpose of coping with the “explosion of complexity” problem in control law design. The key of the scheme is that we use a first‐order filter to link each subsystem, so that the derivative of some nonlinear functions can be avoided. As a result, the final control law can be greatly simplified. The application of this scheme to a flight control system shows that both the tracking performance and the control effort can be improved significantly in comparison with earlier research. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

具有理想跟踪特性的鲁棒变结构模型参考自适应控制

针对相对阶为1的定常线性被控对象,提出了一种控制增益可切换的鲁棒变结构模 型参考自适应控制方案.该方案在对象参数及高频增益符号均未知的情形下,可确保跟踪误 差满足预先给定的过渡过程性能指标,即超调量、过渡过程时间和稳态误差.     

带有迭代学习外环的快速路入口匝道无模型自适应预测控制

针对快速路交通系统复杂时变以及难以建模的特点,首先,本文设计了基于无模型自适应预测控制的快速路入口匝道控制方案.其次,根据快速路交通系统具有重复性特点,本文在无模型自适应预测控制方法的基础上引入开环迭代学习控制,提出一种带有迭代学习前馈外环的无模型自适应入口匝道预测控制方案.相比无模型自适应预测控制方案,该方案可以利用迭代学习前馈控制器补偿系统可重复扰动,实现系统的完全跟踪.值得说明的是,预测控制器和学习控制器可以独立工作也可以联合工作.最后,文章给出了控制方案的收敛性分析,并通过交通流仿真验证了所提控制方案的有效性.     

Pseudo-decentralized switching control

The decentralized control of plants with uncertain mathematical models is studied in this paper. In particular, it is assumed that the plant is described by a continuous LTI model, which is contained in a specified family P? of plant models, and in this case it is assumed that a family of decentralized controllers has been found to satisfactorily control the models contained in P?. A switching control scheme is then proposed that uses the input-output information of each agent to switch between the local candidate controllers in each corresponding agent. A binary communication link is assumed to exist between the local control agents to assure that all agents switch to the next candidate controller, simultaneously. Simulation results, using the proposed decentralized scheme, are given and compared with the centralized scheme.     

Nonlinear model predictive control scheme for stabilizing annulus pressure during oil well drilling

This paper presents a nonlinear model predictive control scheme for stabilizing the well pressure during oil well drilling. While drilling, a fluid is pumped through the drill string and the drill bit, and is returning through the annulus between the drilled well and the drill string. Varying reservoir conditions and fluctuation in circulation flow rates cause sudden variations in the pressure conditions along the well. To compensate for these pressure fluctuations, the annulus choke valve opening can be adjusted. The proposed control scheme is based on a first-principles two-phase flow model using spatial discretization of the complete well. The optimal future choke settings are found using the Levenberg–Marquardt optimization algorithm. This control scheme is evaluated against two other control methods, a manual control scheme and a standard feed-back PI-control scheme of the choke valve with feed-forward control of the pump rates. The PI-control parameters are found using the Ziegler–Nichols closed-loop method based on simulations from a low-order model. The results show that both the PI-control scheme and the model predictive control scheme are superior to manual control. However, the PI-control scheme requires that the control parameters are re-designed when the operating conditions are deviating from the original design conditions. The model predictive control scheme will perform within the operating limits as long as the detailed model is able to describe the actual conditions of the well.     

DoS攻击下网络化控制系统基于观测器的记忆型事件触发预测控制

本文研究了DoS攻击下网络化控制系统记忆型事件触发预测补偿控制问题. 首先, 由于网络带宽资源有限 和系统状态不完全可观测性, 引入了记忆型事件触发函数, 为观测器提供离散事件触发传输方案. 然后, 分析了网络 传输通道上发生的DoS攻击. 结合上述记忆型事件触发方案, 在控制节点设计一类新颖的预测控制算法, 节省网络 带宽资源并主动补偿DoS攻击. 同时, 建立了基于观测器的记忆型事件触发预测控制的闭环系统, 并且分析稳定性. 通过线性矩阵不等式(LMI)和Lyapunov稳定性理论, 建立了控制器、观测器和记忆型事件触发矩阵的联合设计方案, 并验证了该方案的可行性. 仿真结果表明, 该方案结合记忆型事件触发机制可以有效补偿DoS攻击, 节约网络带宽 资源.     

Hierarchical neuro-fuzzy current control for a shunt active power filter

This paper presents the design of a hierarchical neuro-fuzzy current control scheme for a shunt active power filter compared with a single fuzzy controller scheme. A single fuzzy controller scheme is presented first and an ANFIS based neuro-fuzzy controller is connected hierarchically to the first one to improve the performance. Simulation results show that harmonic compensation is achieved with both schemes, however switching performance is superior for hierarchical scheme. The method of switching controller development in this paper is new and can be applied to other power electronic converter applications for improved performance.     

A variable structure MRAC with expected transient and steady-state performance

A new output feedback variable structure model reference adaptive control (VS-MRAC) scheme is proposed in this paper for uncertain plants with relative degree one. The scheme is based on the existing VS-MRAC structure together with a high gain switching mechanism to adjust the variable structure control signal. The main features of the scheme are that (1) the pre-specified transient and steady-state performance specifications for tracking error can be guaranteed, (2) it does not require the plant high frequency gain sign to be known a priori, (3) the usual assumption for MRAC system that the reference model is strictly positive real (SPR) is not needed and (4) the plant input disturbance, which is assumed to be unknown but bounded, can be completely rejected.     

PID控制在倒立摆实时控制系统中的应用

针对单级倒立摆系统的单输入双输出、强非线性、强耦合的不稳定系统,提出了双回路PID控制方案。通过仿真试验研究了双回路PID多种组合控制方案的可行性,并选出最佳方案——双回路PD-PD控制方案。通过在实际单级倒立摆装置上的实时控制试验证实所提出的控制方案可以实现了对小车位置和摆杆偏角的同时闭环控制。