WorldFIP和FF非周期信息调度的性能比较

World FIP和FF都采用集中控制的方式来管理周期信息的通讯,但是二者对非周期信息的通讯管理有着本质的不同。World FIP利用查询方式发送非周期信息,而FF采用轮循的方式并辅以PT令牌来完成非周期信息的通讯。讨论了两类总线不同的非周期管理模式,给出了两类总线不同非周期通信模式的利用率公式,比较了在不同非周期到达率下,两种模式的性能     

1553B总线上消息的实时调度

为了优化1553B总线传输性能,降低总线上消息传输的延迟时间,讨论了周期消息和非周期消息混合传输情况下总线上的消息调度策略。首先,借鉴周期任务的调度模型对周期消息进行建模,提出了改进的速率单调消息调度算法。然后,利用排队论建立非周期消息的M/M/1排队模型,定量分析了1553B总线的平均响应时间和总线利用率等时间性能参数,并对非周期消息的延迟时间进行优化,推导出总线最优服务率和最小平均延迟时间的计算公式,给出了非周期消息的调度算法。最后,对上述算法在消息混合传输下的可调度性进行了验证。实验结果表明,在总线利用率达96%时,混合消息的平均响应时间为0.713ms。在消息混合传输的情况下,非周期消息的平均响应时间和M/M/1排队模型下理想的非周期响应时间偏差不超过10%。上述算法时间响应特性良好,能够保证周期消息和非周期消息的实时调度。     

Communication performance analysis and comparison of two patterns for data exchange between nodes in WorldFIP fieldbus network

Data exchange patterns between nodes in WorldFIP fieldbus network are quite important and meaningful in improving the communication performance of WorldFIP network. Based on the basic communication ways supported in WorldFIP protocol, we propose two patterns for implementation of data exchange between peer nodes over WorldFIP network. Effects on communication performance of WorldFIP network in terms of some network parameters, such as number of bytes in user’s data and turn-around time, in both the proposed patterns, are analyzed at length when different network speeds are applied. Such effects with the patterns of periodic message transmission using acknowledged and non-acknowledged messages, are also studied. Communication performance in both the proposed patterns are analyzed and compared. Practical applications of the research are presented. Through the study, it can be seen that different data exchange patterns make a great difference in improving communication efficiency with different network parameters, which is quite useful and helpful in the practical design of distributed systems based on WorldFIP network.     

TTCAN网络调度平台的设计优化

TTCAN是近几年发展起来并广泛应用于汽车以及其它一般工业控制系统的实时传输协议~([1]).分析了TTCAN网络平台对于周期性消息及非周期性消息的调度策略,分别对其进行改进,并通过遗传算法对系统矩阵周期调度表进行优化,之后利用Simulink中的Stateflow工具针对一般工业控制系统建立了TTCAN网络调度仿真平台,并对仿真平台进行优化,优化后的仿真平台较好地提高了网络系统带宽利用率,增大了总线通信量,降低了各传感器节点周期性消息的响应时间和非周期性消息的延时时间,从而改善了网络平台的通信实时性能.     

电动汽车CAN总线混合调度方法的研究

电动汽车网络控制系统中传输的消息越采越多，固定调度方法已经不能满足系统的消息传输。为此本文提出一种混合调度方法采对电动汽车中的消息进行调度。实验证明该方法改善了电动气车的整体控制性能，使得网络的利用率得到提高，消息的截止期得到满足。     

A new high-performance open CNC system and its energy-aware scheduling algorithm

Computer numerical control (CNC) systems are shifting to a direction of open architecture which has better flexibility, adaptability, versatility, and expansibility. Existing CNC systems tend to have a high level energy consumption. This paper introduces a new open CNC system based on the low-power embedded platform, named open and high-performance CNC (OHP-CNC). OHP-CNC is able to achieve high precision, high efficiency, and low power consumption by making use of international standards, open components such as hardware and software, and an energy-aware real-time scheduling algorithm. The proposed algorithm for mixed tasks, including periodic and aperiodic tasks, is divided into two phases. Firstly, the slack time and utilization are calculated on each processor and tasks are assigned to the processor according to the load. Secondly, because there is a trade-off between the energy-saving and the response times of the aperiodic task, the scheduling server is used to schedule aperiodic tasks in order to meet the response time constraints of aperiodic tasks. Meanwhile, periodic tasks recycle the slack time with dynamic voltage scaling technology to achieve low power consumption. Experiment results show that the energy-aware real-time algorithm yields high-performance and effective machining processes.     

MULTIPLE ELECTRONIC CONTROL UNITS CALIBRATION SYSTEM BASED ON EXPLICIT CALIBRATION PROTOCOL AND J1939 PROTOCOL

The rising number of electronic control units （ECUs） in vehicles and the decreasing time to market have led to the need for advanced methods of calibration. A multi-ECU calibration system was developed based on the explicit calibration protocol （XCP） and J1939 communication protocol to satisfy the need of calibrating multiple ECUs simultaneously. The messages in the controller area network （CAN） are defined in the J1939 protocol. Each CAN node can get its own calibration messages and information from other ECUs, and block other messages by qualifying the CAN messages with priority, source or destination address. The data field of the calibration message is designed with the XCP, with CAN acting as the transport layer. The calibration sessions are setup with the event-triggered XCP driver in the master node and the responding XCP driver in the slave nodes. Mirroring calibration variables from ROM to RAM enables the user to calibrate ECUs online. The application example shows that the multi-ECU calibration system can calibrate multiple ECUs simultaneously, and the main program can also accomplish its calculation and send commands to the actuators in time. By the multi-ECU calibration system, the calibration effort and time can be reduced and the variables in ECU can get a better match with the variables of other ECUs.     

一种高可用性的冗余工业实时以太网设计

研究提出了一种自适应双以太网冗余方案。在以太网报文的用户数据区设计了报文时间标签。利用时间标签,采用时间优先法处理冗余报文,实现了具有零故障恢复时间的双网冗余传输通信,提高了系统的实时性;节点利用网络诊断报文建立并维护网络状态映射表,可映射网络中其他节点的故障状况;并根据报文的重要性将其进行分类,次要报文在网络状态良好时在双网上分散传输,有效地降低了网络的通信负荷。实验证明,通过以上方法可有效提高网络的可用性和安全性。     

基于客户定制生产的车间作业计划

以某离散型制造企业为对象,建立了一种基于客户定制生产的车间作业计划制定模型并给出相应的算法.通过作业优先级设置和工序时间平衡,达到在短时间内生成可用的作业计划.在此基础上,建立起相应的软件模块功能模型,描述了模块的基本功能.最后讨论了车间作业计划制定模型的局限性并给出了相应的解决方法.     

Key Technology of Embedded System Implementation for Software-based CNC System

The software-based computer numerical control(CNC)system includes three types of tasks: periodic real-time tasks,aperiodic real-time tasks,and non-real-time tasks.The tasks are characterized by concurrency,hybridization,and correlation,which make system implementation difficult.The conventional scheduling algorithm can not meet the demands of system implementation in the software-based CNC system completely.The uncertainty factors when running real-time tasks affect control performance by degrading manufacturing accuracy as a result of system resource and processor use restrictions.To address the technical difficulty of embedded system implementation,a novel fuzzy feedback scheduling algorithm based on output jitter of key real-time tasks for a software-based CNC system is proposed.Time characteristics,such as sampling jitter,input-output jitter,and non-schedulability are discussed,followed by quantification through simulations of the impact of time characteristics on manufacturing accuracy.On the basis of this research,the scheduler architecture is designed,and then the algorithm table is calculated.When the system resource changes,the key periodic real-time tasks meet their deadlines by means of dynamically adjusting the task period.The simulated results show that the machining precision rises by an order of magnitude for the proposed scheduler in resource-constrained software-based CNC systems.Moreover,unlike conventional feedback scheduling methods,the algorithm in this paper does not rely on the availability of task execution times and is easy to implement while incurring only a small overhead.     

隐形卡的构形及信息微机输入法

文中介绍了隐形卡的构形、红外线识别信息方法、“排式信息”微机输入方法及“排式信息”的编排方法;解决了非匀速插卡时可靠读取信息的问题,并给出了微机程序流程图。     

一种非周期软实时系统的动态调度方法

本文介绍了一种针对非周期软实时系统的动态调度方法。该方法以DM调度算法为基本调度算法，把非周期软实时系统看作一个多优先级排队系统，根据不同优先级的任务的队列长度来动态调整系统的参数。该方法能在统计意义上确保系统的实时性，同时又能兼顾系统的QoS需求。实例表明该方法能提高系统的实际利用率和降低系统的时限错过率，是一种有效的载荷管理方法。     

Modularized simulation for lot delivery time forecast in automatic material handling systems of 300 mm semiconductor manufacturing

The more accurate the forecast is to lot delivery time, the more effective it is in fab scheduling. In fab operations, scheduling is the major impact factor of tools capacity allocation, tools utilization control and bottleneck management. However, there is no effective method to estimate delivery time in 300 mm automatic material handling systems (AMHS) operation. Computer simulations are authentic, but they are either too complex to model fab operations as well as the whole AMHS, or too time-consuming to simulate with a full-scaled fab model. This paper proposes an analytic methodology to estimate the loop-to-loop delivery time for differentiated lots in a 300 mm AMHS environment. Combining simulation and statistics techniques, we develop a modularized simulation method (MSM) for delivery time forecast of priority lots. Numerical experiments based on data from a local 300 mm manufacturing fab are conducted. Simulation demonstrates that the MSM has credible results in estimating lot delivery times. The time differences between MSM and simulation for both priority lots and regular lots are 0.2 s and 0.1 s, respectively. Using the MSM method to forecast AMHS delivery time is a great contribution for streamlining shop floor operations, such as scheduling and dispatching, for eliminating time delays in the 300 mm automatic environment.     

基于时间约束的汽车FlexRay网络动态段参数设计

针对FlexRay网络参数设计问题,定性分析了动态段长度等参数和消息ID分配对网络性能的影响,推导出动态段带宽利用率和消息最坏响应时间计算方法。以消息响应时间为约束,以最大带宽利用率和最小整体响应时间为设计目标,给出了FlexRay动态段长度和帧ID的优化设计模型及求解算法。以CANoe和DaVinci Network Designer为仿真平台进行实验,结果表明,该设计方法能够保证较高的动态段带宽利用率和较小的消息响应时间。     

嵌入式Linux进程调度的研究

通过对Linux进程调度函数源码的分析，深入剖析了kernel核进程调度流程、调度时机、进程PCB和进程调度的依据。针对进程调度中出现的优先级反向问题，给出了基本优先级继承协议和优先级上限继承协议两种解决方法。     

优先约束的混合实时任务动态调度算法

为了对较大规模问题在短时间内给出满意的解并调度随机到达的非周期任务,提出了一种动态混合调度算法。在第一个截止期限错失时刻,通过分析系统的运行情况,推导出具有优先约束的实时任务可调度的充分条件。在系统运行前,判定周期任务的可调度性,预分配足够的处理机。当非周期任务到达系统时,在保证周期任务可调度的前提下重新给周期任务和非周期任务分配处理机。该算法具有多项式时间复杂性,适合解决较大规模的多处理机调度问题。实验结果表明,该算法有效提高了处理机的利用率和非周期任务的接收率。     

Modularized simulation for lot delivery time forecast in automatic material handling systems of 300?mm semiconductor manufacturing

The more accurate the forecast is to lot delivery time, the more effective it is in fab scheduling. In fab operations, scheduling is the major impact factor of tools capacity allocation, tools utilization control and bottleneck management. However, there is no effective method to estimate delivery time in 300 mm automatic material handling systems (AMHS) operation. Computer simulations are authentic, but they are either too complex to model fab operations as well as the whole AMHS, or too time-consuming to simulate with a full-scaled fab model. This paper proposes an analytic methodology to estimate the loop-to-loop delivery time for differentiated lots in a 300 mm AMHS environment. Combining simulation and statistics techniques, we develop a modularized simulation method (MSM) for delivery time forecast of priority lots. Numerical experiments based on data from a local 300 mm manufacturing fab are conducted. Simulation demonstrates that the MSM has credible results in estimating lot delivery times. The time differences between MSM and simulation for both priority lots and regular lots are 0.2 s and 0.1 s, respectively. Using the MSM method to forecast AMHS delivery time is a great contribution for streamlining shop floor operations, such as scheduling and dispatching, for eliminating time delays in the 300 mm automatic environment.     

型面3维误差分离理论与应用

针对3维型面采用误差矩阵和误差矢量表示方法，建立3维误差模型。对傅立叶变换的分频特性进行了理论分析，采用傅立嚅变换方法对3维误差进行分析，并进行了实践验证，实现对3维误差模型的频率分离，获得周期误差的幅一频信息，采用2维滤波与滤波器处理技术进行频率误差信息提取，从而实现有用信息的提取，为误差的可补偿研究提供补偿依据。     

基于遗传算法的生产周期和生产费用双目标双向车间调度问题的研究

优化车间生产调度的目的不仅仅是为了缩短生产周期,更重要的是为了提高生产效率,降低生产成本。采用改进的遗传算法结合神经网络,以生产周期和生产费用为双目标,实施调度优化。编排车间作业采用两种不同的调度方法,即满足关键工件交货期的倒排法和综合考虑生产周期和生产成本的顺排法———双向双目标调度的方法。调度的策略是在确保客户交货期要求的前提下,充分利用现有资源,缩短产品生产周期、降低企业生产成本,提高企业的市场竞争力。     

分布式混合优化调度方法研究

在敏捷制造环境下车间组织模型不再只是物理上集中在一起的生产作业车间，其制造资源分散在不同地域的企业联盟中。引入了部分全局优化调度的概念，将作业按其紧迫程度进行分组并完成优化；针对分布式调度中优化与动态响应的冲突问题，提出了一种将优化调度和分布式动态调度相结合的混合调度控制方法；设计了多Agent的动态调度系统结构，描述了处于不同角色Agent的运作过程；详细阐述了系统中可能遭遇的随机干扰事件及其动态应对策略。给出了算例，对计算结果进行了分析。