一种简易数字控制频率特性测试仪的设计

设计了一个以STM32F407为控制核心的简易频率特性测试仪系统,可以实现了在1M～40MHz频率范围内,对双端口网络的幅频特性和相频特性进行测量。系统采用DDS芯片AD9854产生稳定的正交扫频信号源,根据零中频正交解调原理,由模拟乘法器AD835和二阶有源低通滤波器组成正交解调电路,实现被测网络幅度和相位参数模拟量的提取,然后由高精度ADC芯片ADS1271完成模数转换,再将信号送STM32F407处理后,最后由显示模块显示被测网络的幅频特性和相频特性。通过测试,本系统能正确的绘制被测网络的幅频特性曲线,显示其中心频率和3dB带宽,并且能够任意设置扫频步进和扫频范围,实现频率的粗扫描和精细扫描,其电压增益精度优于0.5dB,相位精度优于5度。     

PLC在煤气加压站的应用

随着微电子技术的飞跃发展,计算机技术和网络通讯技术的进步,PLC已经发展成为“以微处理器作基础,集3C技术为一体”的新型工业控制装置。当前,PLC广泛应用于钢铁、采矿、机械制造、化工、能源等领域。我公司充分应用PLC技术对西区储配站站控系统进行改进和完善,为用户的安全用气提供更优质的服务。     

Robust PID control of fully-constrained cable driven parallel robots

In this paper dynamic analysis and robust PID control of fully-constrained cable driven parallel manipulators are studied in detail. Since in this class of manipulators cables should remain in tension for all maneuvers in their workspace, feedback control of such robots becomes more challenging than that of conventional parallel robots. In this paper, structured and unstructured uncertainties in dynamics of the robot are considered and a robust PID controller is proposed for the cable robot. To ensure that all cables remain in tension internal force concept is used in the proposed PID control algorithm. Then, robust stability of the closed-loop system with proposed control algorithm is analyzed through Lyapunov direct method and it is shown that by suitable selection of the PID controller gains, the closed-loop system would be robustly stable. Finally, the effectiveness of the proposed PID algorithm is examined through experiments on a planar cable driven robot and it is shown that the proposed control structure is able to provide suitable performance in practice.     

EACLE : Energy-Aware Clustering Scheme with Transmission Power Control for Sensor Networks

In this paper, we propose a new energy efficient clustering scheme with transmission power control named “EACLE” (Energy-Aware CLustering scheme with transmission power control for sEnsor networks) for wireless sensor networks, which are composed of the following three components; “EACLE clustering” is a distributed clustering method by means of transmission power control, “EACLE routing” builds a tree rooted at a sink node and sets the paths from sensor nodes taking energy saving into consideration, and “EACLE transmission timing control” changes the transmission timing with different levels of transmission power to avoid packet collisions and facilitates packet binding. With an indoor wireless channel model which we obtained from channel measurement campaigns in rooms and corridors and an energy consumption model which we obtained from a measurement of a chipset, we performed computer simulations to investigate the performance of EACLE in a realistic environment. Our simulation results indicate that EACLE outperforms a conventional scheme such as EAD (Energy-Aware Data-centric routing) in terms of communication success rate and energy consumption. Furthermore, we fully discuss the impact of transmission power and timing control on the performance of EACLE.     

A new formulation of fringing capacitance and its application to the control of parallel-plate electrostatic micro actuators

Though the effect of fringing field in electrostatic parallel-plate actuators is a well-understood phenomenon, the existing formulations often result in complicated mathematical models from which it is difficult to determine the deflection of the moving plate for given voltages and hence, they are not suitable for accurate actuation control. This work presents a new formulation for tackling the fringing field, in which the effect of fringing field is modeled as a variable serial capacitor. Based on this model, a robust control scheme is constructed using the theory of input-to-state stabilization (ISS) and backstepping state feedback design. This method allows loosening the stringent requirements on modeling accuracy without compromising the performance. The stability and the performance of the system using this control scheme are demonstrated through both stability analysis and numerical simulation.     

典型电缆连接器的装配质量控制措施

电缆连接器广泛应用于航空航天、军工、电子产品等领域,为了保证产品的质量,提高产品的可靠性,有必要对其进行研究.主要介绍了XKE型和SCSI型及J30J型电缆连接器的特性、用途和装配工艺控制措施.通过实际应用,取得了较好的效果.     

从安全管控角度浅谈基于可信的网络安全

网络安全与可信计算的融合,是信息安全发展的必然趋势,安全管理也从单纯的安全参数配置和安全事件统计,朝着基于可信的安全管理与控制方向发展。文中针对目前网络安全威胁现状,阐述了建立在可信基础上的网络安全内涵,探讨了基于可信的安全管理与控制机制,并就几个影响后续发展的重要技术问题进行了初步分析和展望。     

基于全数字伺服控制单元的位置控制系统设计

阐述了基于全数字伺服控制单元的位置控制系统的特点,并且对运动控制算法进行分析,介绍了欧姆龙公司最新推出的新型全数字交流伺服控制单元MCW151的原理和性能,阐述基于交流伺服控制单元MCW151的位置控制系统的特点,并且设计了一种新的高精度伺服控制系统。     

采用GPS数据实现激光反射方向的控制

利用GPS测得激光预定反射方向上某目标的三维坐标,转化成相对平面反射镜中心的方位角与俯仰角,通过控制平面反射镜的法线方向达到反射激光到达预设目标的目的.结果表明该方法简单、容易实现并且精度较高.