A new continuous sliding mode control approach with actuator saturation for control of 2-DOF helicopter system

The 2-degree of freedom (DOF) helicopter system is a typical higher-order, multi-variable, nonlinear and strong coupled control system. The helicopter dynamics also includes parametric uncertainties and is subject to unknown external disturbances. Such complicated system requires designing a sophisticated control algorithm that can handle these difficulties. This paper presents a new robust control algorithm which is a combination of two continuous control techniques, composite nonlinear feedback (CNF) and super-twisting control (STC) methods. In the existing integral sliding mode (ISM) based CNF control law, the discontinuous term exhibits chattering which is not desirable for many practical applications. As the continuity of well known STC reduces chattering in the system, the proposed strategy is beneficial over the current ISM based CNF control law which has a discontinuous term. Two controllers with integral sliding surface are designed to control the position of the pitch and the yaw angles of the 2- DOF helicopter. The adequacy of this specific combination has been exhibited through general analysis, simulation and experimental results of 2-DOF helicopter setup. The acquired results demonstrate the good execution of the proposed controller regarding stabilization, following reference input without overshoot against actuator saturation and robustness concerning to the limited matched disturbances.     

Model-based adaptive sliding mode control of the subcritical boiler-turbine system with uncertainties

As higher requirements are proposed for the load regulation and efficiency enhancement, the control performance of boiler-turbine systems has become much more important. In this paper, a novel robust control approach is proposed to improve the coordinated control performance for subcritical boiler-turbine units. To capture the key features of the boiler-turbine system, a nonlinear control-oriented model is established and validated with the history operation data of a 300 MW unit. To achieve system linearization and decoupling, an adaptive feedback linearization strategy is proposed, which could asymptotically eliminate the linearization error caused by the model uncertainties. Based on the linearized boiler-turbine system, a second-order sliding mode controller is designed with the super-twisting algorithm. Moreover, the closed-loop system is proved robustly stable with respect to uncertainties and disturbances. Simulation results are presented to illustrate the effectiveness of the proposed control scheme, which achieves excellent tracking performance, strong robustness and chattering reduction.     

新型静电除尘装置在电子玻璃生产线的应用

介绍了新型静电除尘设备在超薄玻璃生产线的优势,系统分析了老式结构的缺陷,随着超薄玻璃的广泛应用,此设备是不可或缺的一个关键装置。新型结构的设计及应用,极大提高了玻璃生产的质量。     

Nonsmooth stabilizability and feedback linearization of discrete-time nonlinear systems

We consider the problem of stabilizing a discrete-time nonlinear system using a feedback which is not necessarily smooth. A sufficient condition for global dynamical stabilizability of single-input triangular systems is given. We obtain conditions expressed in terms of distributions for the nonsmooth feedback triangularization and linearization of discrete-time systems. Relations between stabilization and linearization of discrete-time systems are given.     

A canonical structure for constrained optimal control problems

We consider a general class of optimal control problems with regional pole and controller structure constraints. Our goal is to show that for a fairly general class of regional pole and controller structure constraints, such constrained optimal control problems can be transformed to a new one with a canonical structure. A three-step transformation procedure is used to achieve our goal, which essentially amounts to repeated augmentations of plant dynamics and repeated reductions of the controller. The transformed problem is one of the standard optimal static output feedback with a decentralized and repeated structure.     

Stabilizing controllers for discrete bilinear systems

In this paper, we study stabilizing controllers for time varying bilinear systems. Here, the feedback function, f in our paper is for larger classes than those given in the current literature. We establish existence theorems for stabilizing bilinear systems by output feedback from a large class. The main theorems basically state that under broad conditions, the zero state of the systems can be made asymptotically stable by output feedback. Following these stabilizing theorems, a new design procedure for the feedback control law is presented. Application of the new theorems is illustrated by a simulation example.     

焊接与切割设备的使用和维修(五十二)--TIG焊机的使用与维修

讲述了并接电容排除WS-200钨极氩弧焊电流表减动作失灵的方法。详细分析了WSE-315氩弧焊机的原电路电流反馈和改进后的电流反馈原理;例举了WSE-500多功能脉冲钨极氩弧焊机故障排除的事例。     

知识社群中基于本体的用户模型表示和更新

随着INTERNET的发展,人们在获得知识的同时,也更深刻地了解到知识的重要性。而知识的特殊性以及INTERNET中信息的急速增长,使得人们无法容易找到自己所需要的知识。为了实现这一点,我们在构建知识社群的同时,提出该系统的用户模型的表示和更新,以实现对用户的准确定位,向用户推荐适合文本,并利用相关反馈,追踪和更新用户模型,提高服务的效率。     

一种基于电流反馈放大器的新的通用滤波器

本文介绍了电流反馈放大器（CFA）的基本原理,用四个CFA和几个电阻、电容设计了一种三输入单输出的新的通用滤波器。这种滤波器在无需电阻电容匹配的情况下,能实现二阶的低通、带通、高通、带阻以及全通五种滤波功能。每种滤波功能的特征角频率ω0都能由接地电容调节,而品质因数Q可由接地电阻单独调节。该滤波器对有源和无源元件的灵敏度都不超过1。利用PSPICE软件对电路图进行了仿真,仿真结果与理论分析一致。     

斩波内馈技术在烧结厂除尘风机的应用

就斩波内馈调速技术的原理及在烧结厂溶剂除尘风机上实际应用的节能效果进行介绍。