一种时间触发的多任务调度器设计

复杂的嵌入式系统中,采用传统的前后台单任务控制机制已经不能满足要求。本文在详细分析了时间触发和事件触发模式的优缺点的基础上,设计了一种基于时间触发的多任务调度器;实现了调度器的消息处理机制,并给出了设置硬件定时器的示例代码和周期性任务的处理代码;使用NEC公司的V850平台实现了该调度器,并给出了将该调度器应用于车载音响系统中的模块划分方式和周期性任务的处理方式。     

基于时间触发模式的电子控制系统设计

电子控制系统运行的任务绝大多数是周期性任务,因此,采用时间触发模式进行设计具有合理性.本文详细介绍了时间触发合作式调度器的机制,并与抢占式设计调度器进行了比较;给出了一个使用时间触发模式开发太阳跟踪器的设计实例.     

时间触发模式下的Protothreads设计应用

Protothreads是一种无需堆栈的极轻量级线程。本文旨在讨论Protothreads在时间触发模式系统中所能发挥的优势。以一个具体例子为依据,详细介绍了如何使用经过改进之后的Protothreads构建一个多任务调度器,并使之顺利应用于时间触发模式的系统中。     

液压制动能量再生系统的电子控制系统设计

基于时间触发模式的混合调度器理论,设计了液压式制动能量再生系统（HBRS）的电子控制系统。建立功能模块模型,在对各功能模块的瞬时特征和互联特征分析的基础上划分了系统任务,并设计了调度器任务运行时序。最后通过仿真验证了调度器的正确性。     

事件/时间触发嵌入式操作系统内核的设计

针对分布式实时系统对操作系统内核的新需要,为避免因时间触发任务相互影响而造成的抖动,研究了时间触发任务的调度器设计,提出了一种改进的调度策略;在开放源代码的uCOSII嵌入式操作系统内核的基础上扩展了时间触发功能,设计了支持事件/时间混合触发的嵌入式实时操作内核TTuCOSII（Time-Triggered Micro Operating System II）。仿真实验表明TTuCOSII具有较高的时间触发精度,良好的调度性能,可以满足事件/时间混合触发的要求。     

改进型时间触发嵌入式系统编程模式

对于成本敏感的嵌入式系统,通常因为资源有限而难以采用抢先式实时多任务操作系统。传统的基于超级循环的前后台编程方法和基于时间触发的合作式多任务编程方法对任务的划分需要较高的技巧。本文通过对基于时间触发合作式调度器的改进,建立了一种适用于小型嵌入式系统的通用编程模式,使这类系统的编程变得清晰、简单。     

支持双重触发的μC/OS-II内核的设计与实现

针对当前大多数嵌入式操作系统不能同时支持时间和事件双重触发的机制,对μC/OS-II内核进行了深入研究,对μC/OS-II的调度代码进行了分析,提出了将系统内核架构设计为上下两层,以时间触发部分为上层主要模块,事件触发部分为下层基础模块的层次性架构。从而使得系统核心的调度器即可以调度TT任务也可以调度ET任务;实验证明,该方法不仅能够支持时间和事件双重触发的任务调度,而且在不影响可靠性和确定性的情况下,提高了系统的灵活性和实时性。     

基于32位单片机的嵌入式系统设计

针对国内32位单片机在工业自动化领域产品设计中的普及使用,结合国外先进实时多任务系统以及传统前后台系统的优点,设计一套由多任务调度机制和前后台中断触发机制相结合的实时操作系统,自动完成任务调度,及任务状态统计分析,通过搭建统一工业级软件运行平台,增强产品的模块化设计,提高产品功能安全性能。     

计算资源共享平台中工作流任务调度研究

提出了计算资源共享平台中具有时间约束的工作流任务调度方法,该方法利用了非集中式的树型应用层覆盖网络拓扑结构,从而可以高效而快速的收集资源的可用信息。采用全局调度器与本地调度器结合的方式,通过定义资源的收集功能过程,使每个节点中的本地调度器能够把自身的资源可用信息提供给全局的调度器,工作流中任务的最后期限时间约束和任务的恢复时间以一种时间间隙的机制来完成。仿真结果表明,分治模式和解方程类的迭代模式的工作流任务能够在平台上成功调度运行,具有比较快的响应时间和低的通信负载。     

基于单调速率调度算法的μC/OS-II多任务周期的设计

嵌入式实时操作系统μC/OS-II对于多任务调度采用让就绪表中优先级最高的任务总是处于运行状态,这种策略在周期性多任务的调度中存在着缺陷,可能使得任务的周期设计不当导致任务不能被调度。通过引入单调速率调度算法,在对多个任务设计任务周期时予以分析,确定每个任务都能被调度。     

虚拟86模式下实时多任务操作系统的研究与实践

本文提出了一 Ｉｎｔｅｌ高档微处理器虚拟８６模式下实现实时多任务操作系统的新方案，首先简述了虚拟８６模式的特性，然后结合Ｖ８６ＤＯＳ操作系统介绍了基于ＤＯＳ的实时多任务系统在虚拟８６５模式下的设计与实现。     

云计算中基于排队系统的任务调度模型研究

为缩短云计算中任务调度过程任务等待时间及提高虚拟机任务调度系统的执行效率,提出一种云环境下基于 排队系统的任务调度模型。对该模型中系统稳态分布和条件随机分解结果进行了分析,给出该模型的稳态队长的随机分解和稳态等待时间,结合数值例子,准确的找到服务率与期望队长、期望等待时间及其它性能指标之间的关系。通过云任务调度系统的仿真,实验结果验证了该模型能够快速地完成云任务的调度,提高了虚拟机资源的平均利用率。     

Input‐to‐state stability of switched nonlinear systems with delay in the active mode detection

A switched nonlinear system subject to disturbances is considered in this paper. The switching signal admits an average dwell time and a state feedback control depending on the system operating modes, detected with a maximum time delay, is applied to the system. In this framework, the input‐to‐state stability problem of the closed‐loop system is addressed. Based on some established existence conditions of mode‐dependent Lyapunov‐like functions, the values of the maximum time delay and the average dwell time that allow to achieve the input‐to‐state stability of the closed‐loop system are determined. In order to obtain more tractable results, the existence conditions of the mode‐dependent Lyapunov‐like functions are given in terms of sum‐of‐squares programming in the case of polynomial nonlinearities. In the linear case, they are expressed in terms of linear matrix inequalities and a procedure for the synthesis of the mode‐dependent controller is provided in this situation. The established theoretical results are illustrated through a control problem of a building ventilation system and a switched control problem of a vehicle suspension system.     

State and mode feedback control strategy for discrete‐time Markovian jump linear systems with time‐varying controllable mode transition probability matrix

In this article, the state and mode feedback control strategy is investigated for the discrete‐time Markovian jump linear system (MJLS) with time‐varying controllable mode transition probability matrix (MTPM). This strategy, consisting of a state feedback controller and a mode feedback controller, is proposed to ensure MJLS's stability and meanwhile improve system performance. First, a mode‐dependent state feedback controller is designed to stabilize the MJLS based on the time‐invariant part of the MTPM such that it can still keep valid even if the MTPM is adjusted by the mode feedback control. Second, a generalized quadratic stabilization cost is put forward for evaluating MJLS's performance, which contains system state, state feedback controller, and mode feedback controller. To reduce the stabilization cost, a mode feedback controller is introduced to adjust each mode's occurrence probability by changing the time‐varying controllable part of MTPM. The calculation of such mode feedback controller is given based on a value‐iteration algorithm with its convergence proof. Compared with traditional state feedback control strategy, this state and mode feedback control strategy offers a new perspective for the control problem of general nonhomogeneous MJLSs. Numerical examples are provided to illustrate the validity of the proposed strategy.     

Adaptive Observer‐Based Global Sliding Mode Control for Uncertain Discrete‐Time Nonlinear Systems with Time‐Delays and Input Nonlinearity

A new discrete‐time adaptive global sliding mode control (SMC) scheme combined with a state observer is proposed for the robust stabilization of uncertain nonlinear systems with mismatched time delays and input nonlinearity. A state observer is developed to estimate the unmeasured system states. By using Lyapunov stability theorem and linear matrix inequality (LMI), the condition for the existence of quasi‐sliding mode is derived and the stability of the overall closed‐loop system is guaranteed. Finally, simulation results are presented to demonstrate the validity of the proposed scheme.     

Robust ℋ︁∞ sliding mode control for nonlinear stochastic systems with multiple data packet losses

In this paper, an ??_∞ sliding mode control (SMC) problem is studied for a class of discrete‐time nonlinear stochastic systems with multiple data packet losses. The phenomenon of data packet losses, which is assumed to occur in a random way, is taken into consideration in the process of data transmission through both the state‐feedback loop and the measurement output. The probability for the data packet loss for each individual state variable is governed by a corresponding individual random variable satisfying a certain probabilistic distribution over the interval [0 1]. The discrete‐time system considered is also subject to norm‐bounded parameter uncertainties and external nonlinear disturbances, which enter the system state equation in both matched and unmatched ways. A novel stochastic discrete‐time switching function is proposed to facilitate the sliding mode controller design. Sufficient conditions are derived by means of the linear matrix inequality (LMI) approach. It is shown that the system dynamics in the specified sliding surface is exponentially stable in the mean square with a prescribed ??_∞ noise attenuation level if an LMI with an equality constraint is feasible. A discrete‐time SMC controller is designed capable of guaranteeing the discrete‐time sliding mode reaching condition of the specified sliding surface with probability 1. Finally, a simulation example is given to show the effectiveness of the proposed method. Copyright © 2011 John Wiley & Sons, Ltd.     

基于Internet的远程控制系统研究

在介绍目前国际上基于Internet的远程控制系统研究现状的基础上，讨论网络远程控制体系的结构组成．分析了控制与观测过程中网络不确定性时延对系统稳定性的影响，提出状态空间的描述方法与基于S域输入输出模型以及相应的时延补偿策略。     

具有强鲁棒性的滑模变结构控制

针对一类高阶不确定非线性系统,基于指数型快速终端滑模的良好特性,提出了一种新的滑模变结构控制．系统状态变量能以较快的收敛速度在有限时间内到达各级滑模面的邻域,并最终收敛到平衡点附近很小的区域．使用李亚普诺夫稳定性理论证明了系统的渐近稳定性,并推导出各级邻域和系统不确定环节的数学关系．Matlab仿真验证了系统的强鲁棒性．     

Stabilization of Hybrid Systems by Feedback Control Based on Discrete‐Time State and Mode Observations

Recently, a kind of feedback control based on discrete‐time state observations was proposed to stabilize continuous‐time hybrid stochastic systems in the mean‐square sense. We find that the feedback control there still depends on the continuous‐time observations of the mode. However, it usually costs to identify the current mode of the system in practice. So we can further improve the control to reduce the control cost by identifying the mode at discrete times when we make observations for the state. In this paper, we aim to design such a type of feedback control based on the discrete‐time observations of both state and mode to stabilize the given hybrid stochastic differential equations (SDEs) in the sense of mean‐square exponential stability. Moreover, a numerical example is given to illustrate our results.     

基于JavaRMI的网络管理系统

提出了一个基于JavaRMI的网络管理系统框架,分析了一个基于该模型的网络管理系统JRNMS的体系结构、功能及关键技术,着重解决了线程的远程管理问题。JRNMS是一个跨平台的、具有高度可扩展性的网络管理系统,可远程动态扩充网络管理任务。通过分离管理线程所执行的代码、数据以及CPU时间分配的方法解决了线程无法动态上载的问题。通过定义全局的状态常量和使用状态驱动,实现了线程的远程控制和状态读取。