A distributed task-oriented real-time programming system

This paper presents a new conception for a distributed task-oriented real-time operating system comprising a compiler, an operating system kernel and communication packages. The system TOROS supplies the tools for a uniform programming of complex process control applications on heterogenous hardware including workstation, PC, programmable controller and microcontroller. The whole control task is split into a set of small modules. These modules are uniquely programmed by defining a state machine and using guarded commands. They are connected logically through calls to tasks provided by other modules. The specification of the modules is done in an hardware independent language. At compile time the modules are distributed to specified target computers. The system automatically translates each module into the particular code and realizes the communication between the modules either on the same computer or through the links.     

Building a real-time kernel: First steps in validating a pure process/ADT model

A model based on simple, unadorned processes and abstract data types has been proposed for the design and implementation of real-time systems. We describe our generally successful experiences in using this model for the construction of a real-time operating system kernel containing services for process control, synchronization, time and input-output. Our work and results focus on the usefulness of the scheme for designing modules at hardware/software interfaces, for predicting deterministic timing behaviour, and for software development.     

Scheduler Modeling Based on the Controller Synthesis Paradigm

The controller synthesis paradigm provides a general framework for scheduling real-time applications. Schedulers can be considered as controllers of the applications; they restrict their behavior so that given scheduling requirements are met. We study a modeling methodology based on the controller synthesis paradigm. The methodology allows to get a correctly scheduled system from timed models of its processes in an incremental manner, by application of composability results which simplify schedulability analysis. It consists in restricting successively the system to be scheduled by application of constraints defined from scheduling requirements. The latter are a conjunction of schedulability requirements that express timing properties of the processes and policy requirements about resource management. The presented methodology allows a unified view of scheduling theory and approaches based on timing analysis of models of real-time applications.     

Adaptive observer and nonlinear control strategy for chemical reactors via neural networks

An adaptive observer and nonlinear feedback control strategy with constraints on control action are developed by using a supervised learning rule of a neural network and the theory of functional-link networks. The convergence of the adaptive observer and the stability of the control system are proven. They are applied to the control of an exothermic stirred-tank reactor. It is shown that an adaptive observer for concentration can be constructed for a reaction system when only temperature measurements are available on line. An adaptive observer is used to identify the pre-exponential Arrhenius constant and to provide on line estimation of the unmeasured reactant concentration for a nonlinear state-feedback controller. Simulations show that the combined observer/controller provides satisfactory closed-loop behaviour, fast responses and strong robustness. Estimated and actual concentration are in good agreement. A nonlinear feedback controller can provide effective feedback control over a wide range of operating conditions.     

基于以太网的多通道时序控制系统设计与实现

针对光电检测系统对时序控制的多样化需求,设计了基于以太网的多通道时序控制器.采用ARM+FPGA架构设计系统控制核心,提高时序信号精度的同时保证了系统的灵活性.利用可编程控制液晶显示器设计用户界面,使人机交互更加方便快捷.基于LabVIEW开发系统上位机软件,上位机通过串口转以太网模块与下位机通信.实验结果表明:控制器时间精度达到1μs,时序信号运行周期可达24 h,并具有外部触发功能和以太网远程控制功能,可应用于有毒有害等危险环境,具有很高的实用价值.     

支持SAR系统高分辨率实时成像的实时系统解决方案

随着信息技术的发展，用于军事、地理、自然灾害扫描探测的合成孔径雷达系统（SAR）对其成像能力的分辨率和实时显示要求越来越高，因此，研究具有自主知识产权的，可以实时处理高分辨率成像的实时系统迫在眉睫，针对实时数据接收，存储，显示和处理等核心问题，提出了一种实时系统解决方案，该方案通过对Linux内核的实时扩展，实现了可达到高处理机利用率的多任务实时调度方法，可支持混成调度；在应用层实现符合实时需求的功能模块；为DSP板开发实时驱动，形成了从硬件驱动层和操作系统层，直到应用软件层的完整实时计算体系。     

基于ARM和WIFI通信的智能开关控制器设计

针对新一代智能家居系统对于大量多功能、高精度自动化控制功能的需求,设计提出了一种基于ARM和WIFI通信的智能开关控制器。以WIFI无线通信技术为基础,用户通过使用Android智能手机或平板电脑等移动智能终端设备,借助设备上的客户端软件对被控设备如灯光照明系统等家居用电设备进行实时无线遥控。采用各种传感器模块对该控制器以及被控设备运行环境进行实时监测,用户可通过移动客户端软件查看了解相关情况。采用TFT液晶显示屏构建用户交互显示模块,对相关信息进行显示,方便用户的日常使用,增强用户的直观体验。通过实验测试,提出的基于ARM和WIFI通信的智能开关控制器达到了对被控设备的智能动态控制要求。该控制器具有结构简单、操作简便、响应迅速、控制功能多样化等优点,应用前景广泛。     

信号交叉口本地智能化系统的设计与实现

针对实现信号交叉口本地智能化的问题,提出一种嵌入平台与信号控制机结合的方案。采用核心板加扩展板结合的方式设计嵌入硬件平台,介绍应用程序模块结构、嵌入操作系统及文件系统的制作与移植等嵌入平台软件层次模块。对系统进行实现与测试,结果表明系统运算时间符合实时交通控制需求。     

C8051F350的多传感器测控平台设计

以C8051F350单片机为主控芯片,结合Labwindows/CVI 2012开发平台,设计了一种多传感器测控系统.系统主要包含以下4个部分:C8051F350控制器模块、传感器模块、受控模块和上位机.系统主要实现2个功能:通过上位机使C8051F350控制器模块控制传感器模块实现温度、湿度、电压和倾角数据的实时检测和显示功能;通过上位机使C8051F350控制器模块控制受控模块实现风扇、直流电机和4路继电器信号的控制功能.     

The Spring kernel: a new paradigm for real-time systems

A real-time operating system kernel, called the Spring kernel, that provides some of the basic support required for large, complex, next-generation real-time systems, especially in meeting timing constraints, is presented. The approach meets the need to build predictable yet flexible real-time systems. Most current real-time operating systems contain the same basic paradigms found in time-sharing operating systems and often use a basic priority-scheduling mechanism that provides no direct support for meeting timing constraints. Spring uses two criteria to classify tasks' interaction with and effects on the environment: importance and timing requirements. Implementation experience with Spring is described     

Detection system of a security robot using multisensor fusion algorithms

This article develops a detection system with a module-based intelligent security robot that has a uniform interface. The detection system contains a power detection module, a gas detection module, an environment detection module, and a fire detection module, etc. The control unit of these modules is a HOLTEK microchip. These modules can communicate with a master module via an I2C interface. The master module communicates with the main controller of the security robot via an RS232 interface. The main controller of the security robot system is an industry personal computer (IPC). It can display the status of these modules on the monitor. These detection modules can enhance the detection results using multisensory fusion algorithms. The user can add or remove the detection modules in any time, and the main controller can acquires sensor signals from these detection modules in real-time. Finally, we present some experimental results using these detection modules, and integrate these modules in a module-based intelligent security robot that executes several scenarios.     

Multiprocessor control system for industrial robots

This paper describes an advanced robot control system based on the three parallel processor boards. The controller has been designed as a general-purpose robot control system dedicated to controlling industrial robots with up to six degrees of freedom. The controller is based on a disk-oriented real-time operating system. The entire set of robot parameters can be monitored and changed by the user on-line. Source files, compilers, linkers and various utilities are provided as well.The main software layers include robot program interpreter, manipulator control facility, robot kinematics, dynamic feed-forward compensation, and digital servos. Basis, hand and joint coordinates are supported. Point-to-point and continuous path motions are provided. Digital and analog IO modules are included for synchronization with an environment. An acquisition system for monitoring and graphical presentation of robot coordinates, velocities and IO signals is provided. The paper ends with some experimental results for a six-degree of freedom robot.     

基于ARM9的工业以太网控制系统智能节点控制器设计

文章提出了一种基于ARM9处理器S3C2410的工业以太网控制系统智能节点控制器的设计方案.该控制器作为工业以太网控制系统的现场控制级,采用Linux作为嵌入式操作系统.主要用于对现场设备进行监控,能够向上位级发送现场实时数据,并接受上位机发送的控制信息,对现场设备进行控制.     

Digital parameter-adaptive control of an air-conditioning plant

Two parameter-adaptive (self-tuning) control algorithms for multivariable systems are described. The algorithms are designed on the basis of linear input-output system models by the combination of recursive parameter estimation and control algorithms: a parameter-adaptive deadbeat controller and a parameter-adaptive optimal state controller. These controllers are applied to a two-input two-output air-conditioning pilot plant, which consists of an air heater and an air humidifier and whose output variables are the temperature and the relative humidity of the air measured at the air outlet. The air-conditioning plant is a nonlinear system and its linearized static and dynamic behaviour is strongly dependent on the operating point characterized mainly by the output variables and by the air flow rate through the plant. The results of the real-time control experiments indicate that it is possible to use the self-tuning features of the parameter-adaptive controllers to stabilize the controlled system after a short adaption phase and to achieve at least a satisfactory control performance for time varying air flow rates and for time varying setpoints of the output variables.     

嵌入式操作系统的硬实时微内核设计

目前的嵌入式实时操作系统存在着内核结构较为复杂、臃肿、稳定性不高、对硬实时应用支持不足等问题.针对这些问题,结合现有的操作系统内核理论及嵌入式实时系统的特殊需求,通过组件化的设计,将内核划分为核心态基本模块及用户态扩展模块,提供多种进程间通讯(IPC)方式,并引入独特的硬实时抢占式调度机制,设计出一种精炼、稳定的硬实时微内核.通过这种设计思路成功开发出了昊鹏(Hopen)操作系统新版内核,应用于最新的3G手机产品上,取得了非常好的效果.     

Robust reinforcement learning control with static and dynamic stability

Robust control theory is used to design stable controllers in the presence of uncertainties. This provides powerful closed‐loop robustness guarantees, but can result in controllers that are conservative with regard to performance. Here we present an approach to learning a better controller through observing actual controlled behaviour. A neural network is placed in parallel with the robust controller and is trained through reinforcement learning to optimize performance over time. By analysing nonlinear and time‐varying aspects of a neural network via uncertainty models, a robust reinforcement learning procedure results that is guaranteed to remain stable even as the neural network is being trained. The behaviour of this procedure is demonstrated and analysed on two control tasks. Results show that at intermediate stages the system without robust constraints goes through a period of unstable behaviour that is avoided when the robust constraints are included. Copyright © 2001 John Wiley & Sons, Ltd.     

Lyapunov based predictive control of vehicle drivetrains over CAN

Vehicle drivetrains are characterized by fast dynamics, subject to physical and control constraints, which make controller design for driveline oscillations damping a challenging problem. Furthermore, in current implementations, the connections between the controller and the physical plant are realized using a controller area network (CAN) as the communication medium, which introduces time-varying delays. As such, the goal of this paper is to provide a control design methodology that can cope with all these challenges and limitations and still yield an effective solution. To this end, firstly, a continuous-time model of a vehicle drivetrain is derived. Then, a method for determining a worst case upper bound on the delays that can be introduced by a CAN is presented, which enables the usage of a polytopic approximation technique to obtain a discrete-time model of the closed-loop CAN system. Thirdly, a non-conservative Lyapunov based predictive controller is designed for the resulting model with time-varying delays, polytopic uncertainty and hard constraints. Several tests performed using an industry validated drivetrain model and the Matlab toolbox TrueTime indicate that the proposed design methodology can handle both the performance/physical constraints and the strict limitations on the computational complexity, while effectively coping with time-varying delays. Preliminary real-time results further validate the proposed methodology.     

Real-time transaction scheduling in database systems

A database system supporting a real-time application, which can be called “a real-time database system (RTDBS)”, has to provide real-time information to the executing transactions. Each RTDB transaction is associated with a timing constraint, usually in the form of a deadline. Efficient resource scheduling algorithms and concurrency control protocols are required to schedule the transactions so as to satisfy both timing constraints and data consistency requirements. In this paper,^† we concentrate on the concurrency control problem in RTDBSs. Our work has two basic goals: real-time performance evaluation of existing concurrency control approaches in RTDBSs, and proposing new concurrency control protocols with improved performance. One of the new protocols is locking-based, and it prevents the priority inversion problem^{, †} by scheduling the data lock requests based on prioritizing data items. The second new protocol extends the basic timestamp-ordering method by involving real-time priorities of transactions in the timestamp assignment procedure. Performance of the protocols is evaluated through simulations by using a detailed model of a single-site RTDBS. The relative performance of the protocols is examined as a function of transaction load, data contention (which is determined by a number of system parameters) and resource contention. The protocols are also tested under various real-time transaction processing environments. The performance of the proposed protocols appears to be good, especially under conditions of high transaction load and high data contention.