Papers also points out that the size of the adscititious powder agglomerate enwrapped by pure al melt , the effect and intensity of stirring shear force and the melt temperature at the beginning of reaction between the adscititious powder and al melt are the main factors affecting the in - situ reaction ongoing velocity 并指出了影响反应进行速度的主要因素是熔体中分散包裹的加入粉末团的尺寸大小、有无搅拌剪切力作用、反应进行时的熔体温度。其中，粉末团尺寸大小与彻底完成反应所需时间的关系最大，大尺寸粉末团将大大延长反应时间。
The mcu of system is the tms320f240 dsp chip produced by ti company . it can put out six ways pwm signal , with ( 10 bits ) a / d , detecting the signal of motor rotor position and phase compensating , the control of closed _ loop speed and stably switch form step _ off to step _ on of bldcm 系统中采用ti公司的tms320f240系列dsp芯片作为微处理器，可以方便的输出6路pwm信号、实现( 10位) a d转换、完成电机转子位置信号的检测与相位补偿、对系统进行速度闭环控制以及实现无位置传感器bldcm从外同步向内同步的平稳切换。
After analysing several kinds of light - weighting structures through ansys , hexagonal speculum structure is confirmed . in the aspect of the controling of speculum , the paper adopts the brushless dc motor which is partial assembled to drive the point speculum and the inductosyn as angle measuring component is selected , the ad2s80a the system is used to get directly angle and angular velocity . double closed - loop speed and position control is designed , as the pid control is the well - developed algorithm , which can achieve stable rotation and precise position control 在指向反射镜的摆动控制方面,采用低速性能好的分装式直流力矩电机作为指向反射镜的驱动电机,并采用感应同步器作为角度测量元件,运用轴角转换器ad2s80a进行角度和速度的输出,采用技术成熟的pid控制方案,进行速度和位置双闭环控制,以实现指向反射镜转动速度的平稳性和位置的精确性。
Because the installation and the maintenance of the speed sensor have brought about many troubles to people who use it , furthermore , it has less accuracy . the exploitation of the speed - sensorless is able to not only reduce the cost of the whole system but also enhance the reliability , so it is under hot discussion nowadays 近年来，各国学者和研究部门致力于无速度传感器控制系统的研究，利用检测定子电压、电流等容易测量的物理量进行速度估算，以取代速度传感器，提高控制系统的可靠性，降低成本，目前已研究出无速度传感器矢量控制系统的实用产品。
In the paper , a speed estimator based on artificial neural network is designed according to the principle of direct torque control , the speed estimator is optimized by genetic algorithm , and the parameters of pid speed adjuster is also optimized by genetic algorithm . a stator linkage and torque observer based on stator resistance estimator using fuzzy neural network is also designed . eventually , the intelligent control of direct torque control system is implemented 本文根据异步电动机直接转矩控制原理，在应用人工神经网络进行速度辨识的基础上，利用遗传算法对神经网络速度辨识器进行了优化设计；运用遗传算法对pid速度调节器的结构和参数进行了整合；在采用模糊神经网络对电机定子电阻辨识的基础上，进行了定子磁链及转矩的观测，为最终实现无速度传感器直接转矩控制系统的智能控制创造了条件。
In this thesis , the basic arithmetic of piv software - cross - correlation arithmetic is introduced in detail , during the data process , through processing the two sequential images by the cross - correlation arithmetic , the vector charts of particles velocity can be obtained , so is the chart of absolute velocity , with velocity decomposed into the radial velocity and axial velocity 本文对试验所获得的连续图像通过互相关算法，获得颗粒速度矢量图，并将速度分解为径向速度和轴向速度，对每一小区域内的颗粒按速度方向不同进行速度平均，获得颗粒的平均速度分布曲线。
