On minimal-order stabilization of minimum phase plants

In this note, the problem of minimal-order stabilization in the case where the plant is minimum phase is studied. A low bound on the order of stabilizers is derived and a set of minimal-order stabilizers are characterized. The low bound is related to the number and location of the plant's unstable and lightly damped poles and the number of zeros. How to construct a minimal-order or low-order stabilizer for a general case is also discussed and the algorithm is provided. Numerical examples are given to illustrate the proposed method.     

线性定常系统镇定问题的输出反馈解

研究了通过Riccati方程中矩阵D的选择,以实现由输出反馈u=-Ly来镇定系统的目的,关于上述问题OFSLQ问题有解D,以使相应的Riccati方程存在正定解P,满足∑(A-BB'P)C-,且给出对某个L,有B'P=LC的充要条件.     

Some remarks on stabilization by means of discontinuous feedbacks

By means of Ryan's necessary condition and of some examples, we see how the interpretation of solutions of systems with discontinuous right-hand side influences stabilizability results for systems which do not admit continuous stabilizing feedback laws.     

基于LMS算法的自适应控制在稳定回路中的应用

成像器稳定跟踪平台的稳定回路设计是一种高精度、高动态响应的伺服回路设计,为实现较好的控制特性,提出了一种基于LMS算法的Adaline网络参数自适应控制方法,根据被控对象的参数变化,实时调整控制器的参数,由于算法相对简单,满足实际工程应用的要求。为了避免自适应算法运算对系统响应快速性的影响,设计了基于常规控制和自适应控制的双模态控制器结构,根据实际工作条件,进行控制策略的实时切换,既保证了系统响应的快速性,又保证了控制精度。实验结果表明,采用该方法实现的稳定回路具有良好的动态和静态特性。     

Stabilizing decentralized model predictive control of nonlinear systems

This note presents a stabilizing decentralized model predictive control (MPC) algorithm for nonlinear discrete time systems. No information is assumed to be exchanged between local control laws. The stability proof relies on the inclusion of a contractive constraint in the formulation of the MPC problem.     

Carbon nanotubes prepared from three-layered copolymer microspheres of acrylonitrile and methylmethacrylate

Carbon nanotubes (CNTs) were synthesized from fine three-layered copolymer microspheres using the polymer blend technique. Diameter of PMMA core/Poly(AN-co-MMA) shell-1/PMMA shell-2 microspheres, prepared by a radical soap-free emulsion polymerization of methylmethacrylate (MMA) and acrylonitrile (AN), was between 400 nm and 500 nm. Microspheres were subjected to melt-spinning at 305 °C, stabilizing in oxygen at 220 °C for 4 h, and finally carbonizing at 1000 °C for 30 min. FE-SEM study of carbonized sample revealed the presence of CNTs arrays on carbon blocks. Similar arrays were observed in a comparative CNTs sample prepared from three-layered microspheres with the pure PAN shells-1 layers. HRTEM showed that the CNTs derived from copolymer microspheres had different structure when compared to the control sample, i.e. CNTs often adhered to each other and contained the internal compartments. The insufficient PMMA shell-2 coating of copolymer microspheres is believed to be a reason for CNTs adhesion. The possible mechanisms of the carbon block formation and the adhesion of CNTs are introduced.     

提高35kV直配电网供电稳定性的措施

“35kV直配供电技术”是中国石油天然气总公司重点推广的节能技术项目。河南油田在运行中发现该配电方式存在局部故障,造成变电所母线残压过低,大量抽油机因交流接触器释放停抽。同时还发现在继电保护方面也存在较严重的问题,影响了配电网供电的稳定性和原油产量。针对上述问题,采取了加装限流电抗器等措施,取得了明显的效果。     

Robustness for time-varying systems

We consider robust optimization for time-varying systems in terms of perturbations of fractional representations. Upper and lower bounds are given for the maximal radius of the operator ball around a given plant which can be stabilized by a single compensator. In the time-invariant case, these numbers are equal.     

沥青橡胶乳液稳定机理研究

使用性能较好的沥青橡胶乳液的制备必须同时满足下列条件：沥青乳液和橡胶乳液的乳化剂类型一致，乳化剂亲水亲油平衡值一致，密度一致，酸碱性一致，表面张力一致．同时还必须满足两个基本要求：相容性好；符合路用要求。     

On stabilization of min-max systems

This note studies min-max systems which are dynamic systems involving three operations (min,max,+). We present a feedback stabilization policy for a class of min-max systems such that the closed-loop systems have a global cycle time which is the same as the maximal Lyapunov exponent of the open-loop systems. Our results are based on structural properties of min-max systems.