一种新型的伺服放大器──GAMX位置定位器

一种新型的伺服放大器──ＧＡＭＸ位置定位器天津市自动化仪表七厂朱秀贞供稿１概述伺服放大器是电动执行机构的电气控制部分，其控制线路主要由前置磁放大器、驱动制动电路、位置反馈信号和断路保护电路组成，其结构为墙挂式。用法国伯纳德技术生产的电动执行机构其中的...

SPC和CPC在汽轮机调节中的作用

为了提高汽轮机组的稳定性,采用伍德沃德公司生产的调速装置、位置定位器与电液转换器共同构成了汽轮发电机调速系统的执行中枢,它们接收来自505调节器的命令实现调节汽门行程的精确定位,从而实现汽轮发电机转速和负荷的准确控制。该系统应用在莱钢50MW发电机中,取得了较好的控制效果和控制精度,确保了机组的长期稳定运行。

电动执行机构在热电站锅炉中的应用与维护

详细介绍了电动执行机构的工作原理及调试方法 ,对其在热电站的应用中出现的问题进行了说明,分析了故障产生的原因和处理方法,并且阐明了重要的日常维护工作,为提高执行机构的运行周期创造了条件。

自感知双线圈式电涡流阻尼器的特性研究

自感知电涡流阻尼器具有非接触、无机械磨损、无需额外的传感装置等优点,在振动控制领域中有着广泛的应用前景。采用双线圈透射式电涡流阻尼装置,其激励线圈作为作动元件,检测线圈作为传感元件,运用阻抗分析法建立变压器型等效电路模型。在此基础上,利用MATLAB软件仿真分析了不同线圈尺寸、激励频率和导电材料情况下,振动偏移量、互感、相位、幅值、涡流损耗功率、轴向力以及互感随时间变化的关系。

Position Sensorless Control for Permanent Magnet Synchronous Motor Using Sliding Mode Observer

An approach of position sensorless control for permanent magnet synchronous motor （ PMSM ） is put forward based on a sliding mode observer. The mathematical model of PMSM in a stationary αβ reference frame is adopted, and the system is controlled by the digital signal processor （ DSP; TMS320LF2407 according to the control achieve closed loop operation of the motor, the stator theory of sliding mode observer. In order to magnetic field should be vertical with the rotor magnetic field and be synchronous with rotor rotating, so the position and speed of PMSM is estimated in real time and the estimated position is modified continuously. The simulation results indicate that the proposed observer has high precision is more robust to the parametric variation and load in estimation of PMSM position and speed, and torque disturbance.

Distributed Localization Algorithm for Wireless Sensor Network Based on Multidimensional Scaling and the Shortest Path Distance Correction

Sensor localization is crucial for the configuration and applications of wireless sensor network (WSN). A novel distributed localization algorithm, MDS-DC was proposed for wireless sensor network based on multidimensional scaling (MDS) and the shortest path distance correction. In MDS-DC, several local positioning regions with reasonable distribution were firstly constructed by an adaptive search algorithm, which ensures the mergence between the local relative maps of the adjacent local position regions and can reduce the number of common nodes in the network. Then, based on the relationships between the estimated distances and actual distances of anchors, the distance estimation vectors of sensors around anchors were corrected in each local positioning region. During the computations of the local relative coordinates, an iterative process, which is the combination of classical MDS algorithm and SMACOF algorithm, was applied. Finally, the global relative positions or absolute positions of sensors were obtained through merging the relative maps of all local positioning regions. Simulation results show that MDS-DC has better performances in positioning precision, energy efficiency and robustness to range error, which can meet the requirements of applications for sensor localization in WSN.

Localization of Small Mobile Robot by Low-Cost GPS Receiver

This article deals with a problem of the robot localization in the outdoor environment by using the GPS （global positioning system） data. In order to navigate the robot, it is necessary to transform the global position into the local map in the form of two-dimensional Cartesian coordinate system. The transformation is based on the model of the Earth-WGS 84 reference ellipsoid. The aim of this article is to experimentally evaluate a set of low-cost GPS receivers applicable as position sensors for small outdoor mobile robots. The evaluation is based on series of measurements executed in different times and places. The measured data is processed by given procedure and acquired positions are transformed into the local coordinate system. Accordingly the accuracy of the measured positions is statistically evaluated. The evaluation of used GPS receivers is done by comparison with data acquired by high-end geodetic GPS system Leica 1200, which is used as a reference GPS system.

Equivalence of Network-Solution and PPP-Solution

The technique of precise point positioning (PPP) is gradually becoming a popular method in GPS data-processing. In GPS observation equation, the unknown parameters can be separated into two parts: global parameters and local parameters. The global parameters include orbit, satellite clock and geodynamic parameters. The local parameters are site-occupation-specific, such as position, tropospheric delay, etc. The formulas of local parameters are firstly derived under the network-solution and the PPP-solution conditions respectively. If the weight matrix of global parameters in PPP-solution is small enough, the cofactor matrices of local parameters are the same as that in network-solution. Then, 16 daily solutions are obtained in both PPP mode and network mode. Three sites are selected to compare the solutions. The experimental results demonstrated that the difference between two solutions in coordinates and tropospheric delays are only few millimeters. This level of difference can be neglected so that the solutions from both PPP mode and network mode can be taken as the same in the actual application.

Target Region Location Based on Texture Analysis and Active Contour Model

Traditional texture region location methods with Gabor features are often limited in the selection of Gabor filters and fail to deal with the target which contains both texture and non-texture parts.Thus,to solve this problem,a two-step new model was proposed.In the first step,the original features extracted by Gabor filters are applied to training a self-organizing map(SOM) neural network and a novel merging scheme is presented to achieve the clustering.A back propagation(BP) network is used as a classifier to locate the target region approximately.In the second step,Chan-Vese active contour model is applied to detecting the boundary of the target region accurately and morphological processing is used to create a connected domain whose convex hull can cover the target region.In the experiments,the proposed method is demonstrated accurate and robust in localizing target on texture database and practical barcode location system as well.

Modified Levenberg-Marquardt algorithm for source localization using AOAs in the presence of sensor location errors

In this paper,by utilizing the angle of arrivals(AOAs) and imprecise positions of the sensors,a novel modified Levenberg-Marquardt algorithm to solve the source localization problem is proposed.Conventional source localization algorithms,like Gauss-Newton algorithm and Conjugate gradient algorithm are subjected to the problems of local minima and good initial guess.This paper presents a new optimization technique to find the descent directions to avoid divergence,and a trust region method is introduced to accelerate the convergence rate.Compared with conventional methods,the new algorithm offers increased stability and is more robust,allowing for stronger non-linearity and wider convergence field to be identified.Simulation results demonstrate that the proposed algorithm improves the typical methods in both speed and robustness,and is able to avoid local minima.

Sliding Mode Control with Perturbation Estimation and Hysteresis Compensator Based on Bouc-Wen Model in Tackling Fast-Varying Sinusoidal Position Control of a Piezoelectric Actuator

In this paper,a sliding mode control with perturbation estimation(SMCPE) coupled with an inverse hysteresis compensator is proposed for the motion tracking control of a microposition system with piezoelectric actuation.The inverse hysteresis compensator is employed to cancel the hysteresis nonlinearity,thus reducing the nonlinear system to a linear system with an inversion error.Then,a SMCPE controller is adopted to deal with all the unmodeled dynamics and disturbances,aiming at improving the dynamic performance and the robustness of system.An experiment of a piezoelectric actuator is presented to demonstrate the feasibility and effectiveness of the proposed control scheme.The result shows that for a fast-rate control input,the proposed method is capable of leading to a good performance of system behavior.