实时数据库系统双机热备机制设计与实现

双机热备计算机系统可实现高任务可靠性,广泛应用于电力系统.针对实时数据库系统提出了一种新颖的双机热备设计技术,基于系统及资源状态检测与监控、双机状态一致性同步、网络通信协议、主备切换机制、数据镜像服务等关键技术实现了模块设计.主控模块对主备服务器工作状态进行仲裁与检测,网络通信模块检测服务器故障,切换控制模块实时响应服务器故障进行切换,配置模块对双机信息进行设置,保证了系统高可靠性持续运行.     

双机热备容错逻辑控制电路设计与仿真

针对传统数字电路系统冗余设计复杂、切换时间长、实现电路体积大等问题,提出一种双机热备容错逻辑控制电路的设计方案.使用VHDL语言设计、一片CPLD芯片实现工作微处理器系统的故障检测与主、备微处理器系统的实时切换等时序控制功能.时序仿真结果表明,该电路判断故障成功率高,切换时间短,可以满足强实时性嵌入式系统的双机热备冗余设计.在高可靠性的微机保护系统等应用场合,该硬件冗余设计方案具有工程设计指导意义.     

基于冗余CAN总线的实时通信系统设计

针对航天现场工业环境对通信系统的可靠性有较高的要求,该文提出了基于冗余CAN总线的实时通信系统设计方法,该方法为系统的CAN网络主节点进行节点冗余设计,同时对CAN网络中的每个节点进行总线冗余设计.当主节点出现故障时系统切换到备份主节点工作,当总线出现故障时系统切换到备份总线上工作.该系统制定了统一的通信协议,系统主控模块FPGA对整个CAN网络中的节点进行实时监控,有效提高了系统数据传输的可靠性.     

基于CAN总线的模块化冗余PLC结构设计

为了满足恶劣环境下计算机系统的高可靠性需求,将冗余技术结合到CAN总线模块的硬件设计与软件开发中,介绍其总体方案、硬件设计方法,给出了部分实现细节及设计流程。测试结果表明,此设计可成功实现CAN冗余模块在总线故障情况下的冗余切换,提高了设备可靠性。     

主备份油源自动切换模块设计分析

直升机液压系统在向主、尾桨操纵作动器提供液压能源时,为保证飞行的可靠性,当主系统发生故障造成失压时,由备份系统代替该主系统向操纵系统提供压力油.液控自动切换模块是保证主备份系统油路切换的组合换向阀块.分析计算了模块的主要结构参数,并通过导阀先于主阀换向的设计,来确保切换模块在主系统压力升降要求范围内实现主备份系统的自动...     

双模冗余器载计算机设计与实现

器载计算机是航天器电气系统的重要组成部分,其可靠性对航天器能否完成任务至关重要。为了保证航天器上计算机在出现故障时仍能正常工作,对双机冗余器载计算机的体系结构、切换策略、判别准则等内容进行了研究,在保留主份机与双机切换电路、备份机与双机切换电路之间的状态工作信号的基础上,通过在主份机、备份机之间新增加一个状态工作信号,提出了一种改进的自主切换策略。实践表明,运用改进的自主切换策略,在双机切换电路中的自主切换模块出现故障时仍能实现自主切换,同时将比较器设计为软件,采用软件表决、软件选通的思路,消除了硬件比较器的关键单点故障,这些容错设计改进能有效地提高器载计算机系统的可靠性,对高可靠器载计算机设计与实现具有较好的工程参考意义。     

冗余I/O模块切换方法的设计与实现

在工业过程控制领域,为了提高系统的可靠性与稳定性,一般都进行冗余设计。因此,设计了一种动态可配置的冗余I/O模块系统,包括控制器、I/O底座、I/O模块和通信总线。其中,冗余通信总线集成在I/O底座中,I/O模块可通过热插拔插入I/O底座。控制器对I/O模块进行配置,可设置成单模块运行或冗余模块运行,并把设置模式下发给I/O模块。I/O模块初始化为"初始化"运行方式。当接收到控制器下发的是冗余运行方式时,I/O模块进行状态决策,决策出主I/O模块和备I/O模块,并把决策结果反馈给控制器。备I/O模块周期性地监视主I/O模块状态,当发现主I/O模块丢失或故障等级高于本身时,则发送命令给对方,让其切换为备I/O模块,当前备I/O模块主动升级为主I/O模块。该方法通过高速通信的方式,实现了主备I/O模块的决策。     

一种航空机载容错计算机的冗余管理技术

文章介绍了作者自行研制的一种航空机载容错计算机系统的设计与实现,系统采用双通道热跟随体系结构。重点分析了基于硬件冗余的冗余管理技术。其冗余主要包括:故障检测、故障隔离、通道切换与故障报警等。     

双冗余CAN总线模块的设计与实现

为满足恶劣环境下计算机系统的高可靠性需求,将冗余技术结合到CAN总线模块的硬件与软件开发中,介绍其总体方案、硬件及软件设计方法,重点描述了在VxWorks系统下的驱动软件实现,给出了部分实现细节及设计流程。测试结果表明,此设计可成功实现CAN冗余模块在总线故障情况下的冗余切换,提高了设备可靠性。     

船载测控雷达测角计算机双机自动切换技术研究

测角计算机虽然采用了冗余设计,但是主备机切换需要通过人工手动实现,难以满足系统实时性要求。针对这种情况,分析了主备机切换的工作任务,确定了主备机自动切换的时机为系统故障和通信中断,利用测角计算机双网通信的特点,在发送的网络数据包中添加故障状态字,并修改网络发数时序,完成主备机故障状态上报从而实现双机自动切换。该方法无需硬件改动,实现过程简单,切换过程仅丢失1帧数据,极大提高了系统可靠性。     

Current control of a PWM power amplifier by an approximate 2-degree-of-freedom digital controller

There is a need for robust current control of a pulse width modulation (PWM) power amplifier whose transient response characteristics do not deteriorate with extensive load changes and/or direct-current power supply voltage changes. In this article, we propose a digital robust controller with bumpless mode switching to control the current of a PWM power amplifier to satisfy the demands and extend the range of an inductive load width. It is necessary to measure the value of the load in order to implement this bumpless mode switching automatically depending on the load range. Therefore, a method of estimating the inductive load is shown. The bumpless mode switching is automatically performed by estimating an inductive value without specifying the value of the inductive load beforehand. That is, the value of the inductive load is estimated during the DDC execution, and the control mode is automatically switched bumplessly according to this estimated value. A digital controller equipped with inductance estimation and bumpless mode switching is realized by a DSP. Some experiments show that the digital controller with the proposed bumpless mode switching can satisfy larger specifications.     

Bumpless switching control for switched systems with partial actuator failures

This study is concerned with the bumpless transfer problem for switched systems with partial actuator failures, in order to obtain smooth system performance output transition. Taking into account that the system requires a controller switching from current sub-controller to a fault-tolerant sub-controller after actuator fault. And bumpless transfer for control input cannot be traditionally designed when the actuator fault occurs, while performance smoothing can be considered and it is actually the ultimate goal of bumpless transfer. Specifically, the actuator fault model is firstly established and partial actuator fault is considered. Then, the system performance output signal is deemed as the main design variable of bumpless transfer, and closed-loop control systems both previous and after controller switching are constructed. Moreover, by using model matching thought and the adaptive sliding mode control technique, a bumpless transfer compensator design strategy is given to drive the performance output variable (after controller switching) to track the one of reference model. At last, simulation results of numeric and application examples demonstrate the effectiveness of the proposed bumpless transfer strategy.     

切换系统的无扰切换控制及其在航空发动机中的应用

利用多Lyapunov函数方法, 本文研究了一类切换线性系统的状态跟踪无扰切换控制问题.首先, 刻画了控制信号在切换时刻处的抖振抑制水平.其次, 通过控制器与切换律的同时设计, 实现了系统的状态跟踪和控制信号抖振抑制.最后, 将所提出的状态跟踪无扰切换控制策略应用于一个涡扇航空发动机模型的控制设计上, 说明了所提出方法的有效性.     

Switched Controllability via Bumpless Transfer Input and Constrained Switching

In this note, we investigate the controllability of linear hybrid systems via bumpless transfer input and constrained switching. By bumpless transfer input, we mean that the control input signals are as close as possible at switching times. By constrained switching, we mean that the switching index sequence is cyclic and the switching time sequence is possibly with pre-assigned duration intervals. While the problem is well motivated in several practical situations, it is also theoretically interesting. A complete criterion for controllability is presented, and a computational procedure is developed for finding a switching signal and a control input to achieve the controllability.      

Bumpless transfer for switched linear systems

This article deals with bumpless transfer for discrete-time switched linear systems. A bumpless transfer controller that is activated at every switching time for reducing the transient behavior is presented. The bumpless transfer control design is based on the finite horizon solution of a linear quadratic optimization problem. Dwell time conditions for assessing asymptotic stability of the closed-loop switched system are provided.     

Finite‐time H∞ bumpless transfer control for switched systems: A state‐dependent switching approach

This paper addresses the finite‐time H_∞ bumpless transfer control problem for switched systems. The main idea lies in designing a state‐feedback controller with amplitude limitation and a state‐dependent switching law to reduce control bumps caused by switching. First, a local bumpless transfer condition is proposed to limit the amplitude of switching controllers at switching points. Second, by introducing a state‐dependent switching law, a prescribed finite‐time H_∞ bumpless transfer control performance is attained even if it does not hold for each subsystem or system state remaining on a switching surface. Third, a sufficient condition verifying the solvability of finite‐time H_∞ bumpless transfer control problem is established by resorting to multiple Lyapunov function method. Finally, the effectiveness of developed method is illustrated by a numerical example.     

故障监测技术在PXI热备冗余测控系统中的应用

文章介绍了一种利用自检测和互监测方法保证故障监测覆盖率和虚警率,适用于双机热备冗余系统的故障监测技术,主要论述了系统的总体结构,讨论了实现系统主从机状态高速自动切换的关键技术,并重点阐述了在PXI热备冗余测控系统中采用的各种故障监测手段,最终实现了在非实时操作系统下热备冗余系统主从机状态的高速自动切换,提高了测试设备自身的可靠性,保证了测试数据的正确性,有效解决了多种场合下地面测控系统要求长时间不间断可靠工作的难题。     

Robust asynchronous bumpless transfer for switched linear systems

This study is concerned with the asynchronous bumpless transfer (ABT) problem for a class of switched linear systems with external disturbances. Asynchronous switching or transfer implies that the transfers between sub-controllers and between sub-plants are asynchronous, and ABT is to ensure that there is no controller/plant-induced bumps or undesirable transients to the process. Specifically, the ABT process is first divided into two parts: robust performance bumpless transfer (RPBT) between sub-plants and robust control bumpless transfer (RCBT) between sub-controllers. Then, with a set of pre-given sub-plants under disturbances and corresponding sub-controllers, the RPBT and RCBT design schemes are, respectively, proposed. The designed RPBT and RCBT compensators are based on model reference adaptive sliding mode control such that the switched system can perform smooth transitions during the whole asynchronous switching process. Furthermore, by using average dwell time technique, the condition for guaranteeing the switched closed-loop system to be stable under ABT is developed. Finally, numerical simulations demonstrate the effectiveness of the proposed method.     

H∞ bumpless transfer for switched LPV systems and its application

In this paper, the approach of the control bumps limitation is generalised and applied to the problem of H _∞ bumpless transfer for a class of switched linear parameter-varying (LPV) systems. The H _∞ bumpless transfer problem is to design a controller with the amplitude limitation and a parameter and modes-dependent switching law to reduce control bumps of the switched LPV systems and satisfy an H _∞ performance index. The key point is to guarantee the bumps limitation constraint of the switched LPV systems by dual design of controllers and a switching law, even though the constraint for each subsystem is unsatisfied. First, a set of switching signals depending on parameters and modes are designed, and a family of switched LPV controllers with the bumps limitation objective are developed via multiple parameter-dependent Lyapunov functions. Then, a sufficient condition ensuring the H _∞ bumpless transfer performance for a switched LPV system is presented in the format of numerically tractable conditions. Finally, the effectiveness of the proposed control design scheme is illustrated by its application to the control design of an aero-engine.     

Feedback stabilization of linear systems with multiple controllers via bumpless transfer inputs and combined switching

For a linear system with multiple controllers, we address the problem of stabilization by means of bumpless transfer inputs and combined switching. The main idea is to design combined switching signals consisting of both state‐feedback logic and time‐driven mechanism. The discontinuities of the control signal during controller switching is compensated over the dwell time intervals, and the compensator is designed so that switching signal keeps unchanged. The state trajectories of the compensated system are proved to be bounded and convergent. A numerical example is presented to verify the effectiveness of the proposed scheme.