共查询到20条相似文献，搜索用时 156 毫秒
1.
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. 相似文献
2.
基于大型铁磁材料的磁致伸缩特性是电力设备发生电磁振动的主要因素,提出了一种适用于普通实验室环境的硅钢片磁致伸缩测量系统,设计了能产生外加磁场的螺线管用来激励硅钢片发生形变,运用陶瓷发热片和温度传感器对硅钢片温度进行调节和控制。基于高精度应变电阻片实现对硅钢片形变的测定,通过理论仿真和实验研究,该装置能准确测量饱和状态和不同温度下的磁致伸缩率。为电磁测量实验及电磁振动分析提供了可靠依据。 相似文献
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In this paper, eddy current sensors and thermocouple sensors were employed to measure the thermal field and thermal deformation of a spindle of a telescopic CNC boring-milling machine tool, respectively. A linear regression method was proposed to establish the thermal error model. Furthermore, two compensation methods were implemented based on the SIEMENS 840D system by using the feed shaft of z direction and telescopic spindle respectively. Experimental results showed that the thermal error could be reduced by 73.79% when using the second compensation method, and the thermal error could be eliminated by using the two compensation methods effectively. 相似文献
4.
TANG Zhi-feng LV Fu-zai XIANG Zhan-qin 《浙江大学学报(A卷英文版)》2007,8(7):1059-1064
This paper presents two numerical realization of Preisach model by Density Function Method (DFM) and F Function Method (FFM) for a giant magnetostrictive actuator (GMA). Experiment and simulation showed that FFM is better than DFM for predicting precision of hysteresis loops. Lagrange bilinear interpolation algorithm is used in Preisach numerical realization to enhance prediction performance. A set of hysteresis loops and higher order reversal curves are predicted and experimentally verified. The good agreement between the measured and predicted curves shows that the classical Preisach model is effective for modelling the quasi-static hysteresis of the GMA. 相似文献
5.
WU Yi-jie LENG Hong-bin ZHAO Zhang-rong CHEN Jun-hua 《浙江大学学报(A卷英文版)》2006,7(12):2073-2078
INTRODUCTION With the development of engine power and ro- tational speed, the load of pin hole of piston is more and more heavy. By analyzing the load of common cylindrical pin hole, the load of each part of the pin hole is asymmetric when the engine is working. The stress of inner side is the most and that of the outer side is the least. So, to improve engine performance, people reduce the stress concentration of the inner side of the pin hole by changing the geometric shape and improve … 相似文献
6.
ZHU Xiao-cong TAO Guo-liang CAO Jian 《浙江大学学报(A卷英文版)》2007,8(12):1928-1937
This paper presents a pressure observer based adaptive robust controller (POARC) for posture trajectory tracking of a parallel manipulator driven by three pneumatic muscles without pressure sensors. Due to model errors of the static forces and friction forces of pneumatic muscles, simplified average flow rate characteristics of valves, unknown disturbances of entire system, and unmeasured pressures, there exist rather severe parametric uncertainties, nonlinear uncertainties and dynamic uncertainties in modeling of the parallel manipulator. A nonlinear pressure observer is constructed to estimate unknown pressures on the basis of a single-input-single-output (SISO) decoupling model that is simplified from the actual multiple-input-multiple-output (MIMO) coupling model of the parallel manipulator. Then, an adaptive robust controller integrated with the pressure observer is developed to accomplish high precision posture trajectory tracking of the parallel manipulator. The experimental results indicate that the system with the proposed POARC not only achieves good control accuracy and smooth movement but also maintains robustness to disturbances. 相似文献
7.
邱浩 《深圳职业技术学院学报》2007,6(4):12-16
针对控制系统故障诊断中存在的不可测干扰，利用一种基于广义逆的未知输入观测器进行故障诊断，并将此方法用于汽车发动机电控系统执行器的故障检测问题。该观测器对控制系统的状态进行重构，通过判断由系统的真实输出和其估计值之间的残差是否超过阈值来检测故障。仿真结果表明，该方法原理简单，对汽车发动机电控系统执行器故障的诊断准确有效。 相似文献
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针对工业生产中难以监控传感器状态的问题,设计一个物联网系统,实现远程传感器数据监控与固件更新。该系统由远程实时监控系统与远程固件更新系统组成,传感器采用嵌入式实时操作系统。在远程实时监控系统中,传感器可调节频率测量数据,基于消息排队遥测传输协议,通过无线网络将数据传输到服务器。为使远程固件更新系统运行符合限制应用协议,传感器连接至轻量级物联网协议服务器,再通过网关连接到hawkBit服务器中,基于超文本传输协议与轮询方式,由hawkBit提供远程更新服务。实践操作表明,该系统操作简单,具有可视化、直观的优点,可满足大型工厂远程实时监控与固件更新需求。 相似文献
9.
以电流型非线性电感Boost 变换器为研究对象,针对非线性电感的磁能损耗特性问题,利用非线性电感值跟随开关状态不同而变化的现象,分析非线性电感电流路径与特定斜率斜坡补偿的数学关系,提出了非线性磁芯电感值与磁滞回线关系的数据模型,代入到Boost变换器的开关状态方程中,经过MATLAB数值方法仿真与电路制作实验验证,结果表明,非线性电感对Boost变换器稳定性产生重要影响,且非线性电感和斜坡补偿方法对变换器的影响是相同的。 相似文献
10.
介绍了应用磁通计和计算机控制系统对磁性材料静态磁滞回线进行测量的方法 ,并对今后该领域测量技术的发展方向进行了预测 相似文献
11.
胡双双 《连云港职业技术学院学报》2011,24(2):28-32
传统民法学界认为合同解除具有溯及力,就意味着合同消灭,回到未订立合同之前的法律状态,恢复原状,但是这种恢复原状的做法过于僵硬。对于合同解除的溯及力问题提出了质疑,确立了清偿关系说,在解约后通过解约损害赔偿对于合同解除权人进行救济。但是这种解约赔偿是根据不同的解约事由拥有不同的归责原则与赔偿范围,不能完全适用损害赔偿的规则。 相似文献
12.
讨论了一类非线性时间连续奇异系统观测器的设计问题,通过线性矩阵不等式,给出了一种易于计算的降维观测器的设计方法;仿真数值例子表明了所给设计方法的有效性。 相似文献
13.
LU Na XU L.J Miedzifiski B 《浙江大学学报(A卷英文版)》2007,8(3):393-396
Undesirable repulsive force between contact members due to both a current path shrink near a real contact area and/or so-called pinch effect is particularly onerous for power switch applications, and results in either contact floating or bouncing which are associated with an electric arc following contact welding. This problem is of great importance for any circuit breaker especially for compact low voltage vacuum circuit breakers. To avoid contact floating at closure and during any inrush current under short circuit conditions, the electrodynamic repulsive force can be employed successfully if we use a special compensation system flexibly combined with the contact itself. However to select and design the compensation system properly, its efficiency has to be known. This paper presents an approach to obtain the electrodynamic force value depending on different shaped (rectangular, square, circle and arch) copper plates used in the compensator by using ANSYS for current values 40 kA RMS. Curve-fitting was done according to the calculating results, the optimization designing of compensation unit is based on them. 相似文献
14.
为了实现在实验室测量磁性膜、条带或丝等多种形态磁性材料的磁滞回线,设计并研制了磁滞回线测量仪。该测量仪的磁感应强度探测器采用双线圈反相连接的设计,磁性材料的样品可以放于任一个探测线圈中,样品的更换方便、快捷。该测量仪通过调试后,对钴基非晶条带和铁基纳米晶条带等多个样品测量出了分辨率高且图形清晰的磁滞回线。 相似文献
15.
A giant magnetostrictive material (GMM) model is developed based on the hysteretic nonlinear theory. The Gram-Schmidt regression method is introduced to determine the parameters of the model as well as the relation- ship between the material strain and the strength and frequency of magnetic field in the model. Through comparison, it is shown that this regression method has good performance in significance test. Then the model is applied to study the motion law of a circular plate in classical GMM transducer, which helps control the transducer rapidly and accurately. 相似文献
16.
This study presents a new method to solve the difficult problem of precise machining a non-cylinder pinhole of a piston using embedded giant magnetostrictive material （GMM） in the component. We propose the finite element model of GMM smart component in electric, magnetic, and mechanical fields by step computation to optimize the design of GMM smart component. The proposed model is implemented by using COMSOL multi-physics V3.2a. The effects of the smart component on the deformation and the system resonance frequencies are studied. The results calculated by the model are in excellent agreement （relative errors are below 10%） with the experimental values. 相似文献
17.
设计了一种基于图像处理的显微镜自动调焦系统,操作者可以通过计算机来操作显微镜,使得操作简单,图像信息的存储、处理、打印方便,更能适用于远距离观测． 相似文献
18.
In this paper,the sensors array technique is applied to the quality detection of aluminum alloy spot welding.The sensors array has three forms,i.e.,linear magnetic sensors array,annular magnetic sensors array and cross magnetic sensors array.An algorithm based on principal component analysis is proposed to extract the signal eigenvalues.The three types of magnetic sensors array are used in the experiment of monitoring the signal.After the eigenvalues are extracted,they are used to build a relationship with ... 相似文献
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倪怀敏 《西南师范大学学报(人文社会科学版)》2009,35(2):93-96
在刑事被害人受到犯罪侵害而又未能从犯罪人或其他渠道得到充分赔偿时,进行法律救助,有效保障刑事被害人权益,是目前社会所关注的焦点。本文就我国刑事被害人法律救助的法律缺陷和对被害人法律救助的现状进行分析,提出刑事被害人法律救助最有效的途径是构建刑事被害人国家补偿制度,并对建立国家补偿制度提出设想,希望能够在刑事被害人的法律救助制度的构建和立法上起到一定的积极促进作用。 相似文献