Design of shared bus DSP board in vector network analyzer

Currently,the mainstream vector network analyzer employs embedded computer module with a digital intermediate frequency （IF） board to form a high performance windows platform.Under this structure,the vector network analyzer needs a powerful encoding system to arbitrate the bus acquirement,which is usually realized by field-programmable gate array （FPGA） chip.The paper explores the shared bus design method of the digital signal processing （DSP） board in network analyzer.Firsty,it puts an emphasis on the system structure,and then the shared bus communication method is described in detail; Finally,the advantages of the shared bus communication mechanism are summanzed.     

Configuration Selection for Reconfigurable Manufacturing Systems by Means of Characteristic State Space

The configuration selection for reconfigurable manufacturing systems(RMS) have been tackled in a number of studies by using analytical or simulation models. The simulation models are usually based on fewer assumptions than the analytical models and therefore are more wildly used in modeling complex RMS. But in the absence of an efficient gradient analysis method of the objective function, it is time-consuming in solving large-scale problems by using a simulation model coupled with a meta-heuristics algorithm. In this paper, a new approach by means of characteristic state space is presented to improve the efficiency of the configuration selection for an RMS. First, a characteristic state equation is set up to represent the input and the output resources of each basic activity in an RMS. A production process model in terms of matrix equations is established by iterating the equations of basic activities according to the resource flows. This model introduces the production process into a characteristic state space for further analysis. Second, the properties of the characteristic state space are presented. On the basis of these properties, the configuration selection in an RMS is considered as a path-planning problem, and the gradient of the objective function is computed. Modified simulated annealing(SA) is also presented, in which neighborhood generation is guided by the gradient to accelerate convergence and reduce the run time of the optimization procedure. Finally, several case studies on the configuration selection for some actual reconfigurable assembly job-shops are presented and compared to the classical SA. The comparison shows relatively positive results. This study provides a more efficient configuration selection approach by using the gradient of the objective function and presents the relevant theories on which it is based.     

ANALYSIS OF TIPOVER STABILITY FOR NOVEL SHAPE SHIFTING MODULAR ROBOT

A novel three-module robot has been introduced. It can change its configuration to adapt to the uneven terrain and to improve its tipover stability. This three-module tracked robot has three kinds of symmetry configuration. They are line type, triangle type, and row type. After the factors and the countermeasures of mobile robot's tipover problem are analyzed, stability pyramid and tipover stability index are proposed to globally determinate the mobile robot's static stability and dynamic stability. The shape shifting robot is tested by this technique under the combined disturbance of pitch, roll and yaw in simulation. The simulation result shows that this technique is effective for the analysis of mobile robot's tipover stability, especially for the reconfigurable or shape shifting modular robot. Experiments on three symmetry configurations are made under unstructured environments. The environment experiment shows the same result as that of the simulation that the triangle type configuration has the best stability. Both simulation and experiment provide a valid reference for the reconfigurable robot's potential application.     

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.     

Review of through-the-earth communication technologies

In this paper, development of through-the-earth communication technologies is summarized, as well as the operating principles and performances. The propagation loss, frequency band and power efficiency are also analyzed. We can know that among these technologies, the antenna induction method is more popular, but the communication system with ground electrodes is more promising due to its high energy efficiency. The communication with elastic wave （seismic） is not suitable for emergency communication when the accidents of rock burst or land slide occur.     

Fault diagnosis for manifold absolute pressure sensor(MAP) of diesel engine based on Elman neural network observer

Intake system of diesel engine is a strong nonlinear system, and it is difficult to establish accurate model of intake system; and bias fault and precision degradation fault of MAP of diesel engine can’t be diagnosed easily using model-based methods. Thus, a fault diagnosis method based on Elman neural network observer is proposed. By comparing simulation results of intake pressure based on BP network and Elman neural network, lower sampling error magnitude is gained using Elman neural network, and the error is less volatile. Forecast accuracy is between 0.015-0.017 5 and sample error is controlled within 0-0.07. Considering the output stability and complexity of solving comprehensively, Elman neural network with a single hidden layer and with 44 nodes is presented as intake system observer. By comparing the relations of confidence intervals of the residual value between the measured and predicted values, error variance and failures in various fault types. Then four typical MAP faults of diesel engine can be diagnosed: complete failure fault, bias fault, precision degradation fault and drift fault. The simulation results show: intake pressure is observable and selection of diagnostic strategy parameter reasonably can increase the accuracy of diagnosis;the proposed fault diagnosis method only depends on data and structural parameters of observer, not depends on the nonlinear model of air intake system. A fault diagnosis method is proposed not depending system model to observe intake pressure, and bias fault and precision degradation fault of MAP of diesel engine can be diagnosed based on residuals.     

DIRECT DISPLACEMENT OF PARALLEL MECHANISM WITH WAVELET NETWORK

A new method solution for the direct displacement of parallel mechanism,wavelet network method,is proposed. Comparing with the classical analytical and numerical methods,this method can be extended to any parallel mechanism with any selected degree of freedom and configuration. A wavelet network suiting to approach multi-input and multi-output system is constructed. The network is optimized by analyzing the sparseness of input data and selecting the fitting wavelets by orthogo-nalization method according to the output data. Then it is applied to solve the direct displacement of a general six-degree-of-freedom parallel mechanism as a numerical example. For comparison purposes,a BP neural network is also used for this problem. Simulation results show that the wavelet network performs better than BP neural network. In addition,the wavelet network learns much faster than BP network.     

A Design of Ultraphonic Tubulous Water Communication System Based on OFDM

<正>In this paper,a design of ultraphonic tubulous water communication system based on OFDM is introduced. The system takes PL3106 which is embedded enhanced 8051 microprocessor as the control chip and takes TMS320VC5509 as the core of OFDM modulation-demodulation.In the paper,the principle of OFDM is introduced briefly.The hardware and software of the system are designed and the experimental results are analysed and concluded.     

Design of Time-Domain Equalizer in Elastic Wave Earth Channel

In low-frequency elastic wave through-the-earth communication system,because of multipath transmission caused by characteristics of the layered earth,the time domain equalizer is different from other wireless communication systems.A modified LMS algorithm of variable step size is proposed based on improvement of traditional LMS.On the base of principle and simulation analysis,the improved Least Mean Square(LMS)algorithm is analyzed and the performances are compared between the improved LMS algorithm and traditional LMS algorithm.In the improved algorithm,the contradiction between convergence speed and the steady-state error is considered at the same time.Therefore,the improved algorithm has good convergence properties and channel-tracking performance.     

PC，PLC与变频器的串行通信控制开发及应用

介绍了在计算机＋PLC＋变频器的控制模式下,如何利用MODBUS协议和自由通信协议实现计算机与PLC、PLC与变频器的通信;开发了计算机与PLC和PLC与变频器之间的通信控制程序。     

基于Visual Basic的PLC与PC机之间串行通信设计

研究了一种基于Visual Basic的OMRONPLC与PC机之间的串行通信,并且给出了通信协议和部分通信程序。该设计具有经济、可靠的特点,并已成功应用于灌溉控制系统中。     

浅谈PLC通信技术

对PLC通信技术进行了一些初步介绍,涉及了数据通信的基本内容、PLC通信原理、PLC网络类型、通信协议及系统设计。     

智能无线通讯系统在供电系统中的研究与应用

无线通信技术的发展过程、以实际问题出发,以10kV高压供电计量为例,介绍无线通信技术的工作原理、组成,同时描述PLC的数据采集应用,该系统解决了企业存在的问题,具有较高的实用、先进、推广价值。     

应用SPComm实现模拟屏与监控主机的串口通信

针对引进的马赛克模拟控制屏和原有的微机运动系统（SCADA系统）的远方终端（RTU）互不通信问题,开发了一套实现模拟屏和监控主机通信的软件,介绍了该软件开发的硬件环境,软件结构,主程序框图和模拟屏通信程序框图,测试证明,该串口通信软件能达到设计要求,并为支持不同的通信夫约的设备之间通信提供了值得借鉴的方法。     

基于ATS仿真系统的网络通信模块的研究与设计

以上海轨交8号线ATS（自动列车监控系统）仿真系统为例，在系统功能模块化的基础之上，根据ATS仿真系统的C／S（客户端／N务器）的实际架构需要，结合TCP／IP、UDP协议，设计出适合仿真系统网络化、通用化的网络通信模块，为系统主机间通信的实时性和可靠性提供保障。     

基于VxWorks的光电火控系统通信接口设计与实现

针对某光电火控系统对于数据实时传输、交互和共享的需求,设计了一种基于VxWorks实时操作系统的多任务通信接口实现方案,结合通信协议,给出了设备串行通信与网络通信的具体实现方法,对系统的实现起到了积极作用。     

基于ARM Cortex-M3内核的嵌入式多机通信系统设计与应用

如今工业生产朝着智能化方向发展,为了降低检测成本,提高监听设备工作的可靠性及实效性,往往需要对多台设备同时进行监控。文章基于以上开发前景,设计了一个嵌入式多机通信系统。ST公司的内核为Cortex-M3的ARM芯片——STM32系列微控制器采用异步通信方式实现多机通信简单方便,因此选用该芯片作为主从机,目的在于简化设备检测流程,得到更有效的结果。     

HART通信协议在现场仪表的使用

随着技术进步,自动化仪表信号的传输从气动信号、电压信号、标准电流信号,一直到数字通讯不断完善。石油炼化企业自动化仪表的使用除了简单的工艺参数检测和监控,还需要一些更详细的参数,于是HART通信协议这种形式简单参数齐全的通讯模式完美的解决了现场数据的收集和控制功能。本文通过现场的实际应用经验,阐述HART通信协议在现场仪表中的使用。     

锅炉承压管管外检测机器人软件系统的设计

介绍了锅炉承压管管外检测机器人的硬件体系，讨论了通信过程中遇到的问题及其解决方案。