Sliding mode control for two-time scale systems: stability issues

The paper presents some results on global exponential stability of linear time invariant systems with different time scales. The full system is decomposed in two reduced ones by means of singular perturbations and a smooth approximation of a Variable Structure Control is synthesized for each of them using Reaching Law approach. The global closed loop stability is then proved for the whole system using Lyapunov methods and a particular state space decomposition. Moreover a literal form for ε∗ (a parameter which measures the minimum separation between time scales) is derived.     

浅谈汽车发动机的电控可变配气机构

目前国外高级轿车普遍使用电控可变配气杌构，其功率性、经济性、安全排放性均达到欧洲四号标准，笔者对电控可变配气杌构的结构与工作原理进行论述，以期能尽快在国内普及。     

虎拟变量法求抗震结构的变形能力可靠度

在考虑地震地面运动加速度及结构参数随机性的基础上,利用虚拟变量法来求抗震结构的形能力可靠度,给出了弹性范围内的基本公式和求解步骤。方法能综合反映地震动及结构参数随机性的影响,计算较为简便。     

Decentralized adaptive recurrent neural control structure

This paper presents a novel decentralized variable structure neural control approach for large-scale uncertain systems, which is developed using recurrent high-order neural networks (RHONN). It is assumed that each subsystem belongs to a class of block-controllable nonlinear systems whose vector fields includes interconnection terms, which are bounded by nonlinear functions. A decentralized RHONN structure and the respective learning law are proposed in order to approximate online the dynamical behavior of each nonlinear subsystem. The control law, which is able to regulate and to track the desired reference signals, is designed using the well-known variable structure theory. The stability of the whole system is analyzed via the Lyapunov methodology. The applicability of the proposed decentralized identification and control algorithm is illustrated via simulations as applied to an interconnected double inverted pendulum.     

变极性等离子弧焊铝合金厚板工艺研究

变极性等离子弧焊是一种新型焊接方法,由于等离子弧对焊接工艺和规范参数的变化比较敏感,获得良好焊缝接头的合理规范参数范围窄、裕度小.本文通过工艺试验,探讨了变极性等离子弧焊16mm铝合金厚板的技术可行性,论述了其相对于传统弧焊工艺的优点.     

平行单级双倒立摆系统的建模与滑模变结构控制

从两摆间无弹簧连接的平行双倒立摆系统特定物理结构出发,结合控制目标进行合理建模与分析,验证所建模型可行性,讨论系统能控性和参数间的关系,并设计了滑模变结构控制律.该文的理论和方法对平行单级双倒立摆的进一步研究工作具有重要意义.     

遗传算法在OBDD变量排序中的应用

编序的二元判决图（ＯＢＤＤ）在电路测试和逻辑验证等方面具有广泛的应用。如何选取一个电路的变量顺序,使得所构造的ＯＢＤＤ最小,是等同于ＮＰＣ的问题。目前有多种寻找电路变量顺序的方法,但都具有一定程度的局限性,不能找到近似的最优解。     

Composing fifth species counterpoint music with a variable neighborhood search algorithm

In this paper, a variable neighborhood search (VNS) algorithm is developed and analyzed that can generate fifth species counterpoint fragments. The existing species counterpoint rules are quantified and form the basis of the objective function used by the algorithm. The VNS developed in this research is a local search metaheuristic that starts from a randomly generated fragment and gradually improves this solution by changing one or two notes at a time. An in-depth statistical analysis reveals the significance as well as the optimal settings of the parameters of the VNS. The algorithm has been implemented in a user-friendly software environment called Optimuse. Optimuse allows a user to input basic characteristics such as length, key and mode. Based on this input, a fifth species counterpoint fragment is generated by the system that can be edited and played back immediately.     

Studies on the heating capacity control of a multi-type heat pump system applying a multi-input multi-output (MIMO) method

This paper describes a method to control capacity of a multi-type heat pump system. Because indoor units are interconnected, alteration of the heating or cooling setting of one indoor unit can influence the performance of the other indoor units. Proportional-integral (PI) controllers were used to assess system performance, and the PI controllers’ gain values were optimized by using a genetic algorithm. A system model was established following a system identification optimization process, and a pseudo random binary sequence was selected as the system identification input signal. A multi-input multi-output (MIMO) controller was more effective in reducing such cross-coupling effects than a single-input single-output (SISO) controller. The temperature at the secondary fluid outlet in the condenser and the saturation pressure at the evaporator were selected as the control variables in the MIMO controller. The experimental results showed that an optimized MIMO controller could reduce overshoot by up to 40% compared with the results using a SISO controller.     

Iterative design of variable fractional-order IIR differintegrators

In this paper, the variable fractional-order (VFO) differintegrator is designed based on IIR-typed Farrow structure. The stability of the designed VFO IIR differintegrator is achieved by incorporating a constrained function into the objective error function. But the minimization of the original objective error function is a highly nonlinear problem, so an iterative quadratic method is proposed to overcome it. Comparing with the design based on FIR-typed Farrow structure, several designed examples, including a VFO differintegrator, a pure VFO differentiator and a pure VFO integrator, are presented to demonstrate the effectiveness of the proposed method.