凸轮逆序测量方法

目前各杂志所发表的关于凸轮测量的文章，所讨论的均是凸轮的顺序测量方法，有关凸轮的逆序测量(反求工程)方法，尚未见于文字。本文将对凸轮的逆序测量方法进行探讨。     

Linking of serially ordered lists by macaque monkeys (Macaca mulatta): List position influences.

Five monkeys (Macaca mulatta) were trained on 2 sets of 3 5-item serially ordered lists. Then, each set was either linked or not in a counterbalanced, within-subject design. Linking entailed training on the 2 pairs that ordered the 3 5-item fists into a single overall 15-item series. Choices on novel pairings after linking conditions attempted to define the unique contributions of knowledge of within-list ordinal position and between-lists link training. With linkage, the series was immediately treated as a 15-item ordered list. Without linkage, choices reflected list positions from initial learning, but continued testing with directional reward yielded gradual ordering into a 15-itern list. Apparently, monkeys remembered and used initial list-position information, but linkage allowed inference of an integrated serial relationship among items. Results supported primate list memory as an organizational process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theory and characteristics of novel variable reluctance 1X resolver

Although brushless resolvers have been used widely as angular position transducers, they are expensive due to their intricate construction, involving a rotary transformer to supply the exciting coils wound on the rotor poles with the current. It is shown theoretically in this paper that the resolver without rotary transformer or brushes can be realized by simple construction, which consists of the stator core with both 4-poles exciting windings and 2-poles output ones and the rotor core carrying no windings. In this resolver the rotor core has minimum gap at one side and a maximum gap at another side of the diameter. It is characterized by an outer surface form that makes the fluctuation part of gap permeance very in proportion to cos θ, where θ represents the angular position of a point in the air gap with respect to the origin on the rotor, the point of minimum air gap. The method determining the rotor form to embody the aforementioned gap permeance variation is also shown. It has been confirmed not only by simulation but also experiment that the 2-phase output voltages of a model designed based on the theory have sinusoidal waveforms with very small harmonic contents. Moreover, the rotor position detected by processing the output voltages through the conventional resolver/digital converter was within acceptable engineering accuracy.     

基于CPLD的光电编码器角位移拟合测速法

针对常用的M法和T法无法满足增量式光电编码器整个测速范围内误差要求的问题,提出了对码盘信号进行角位移拟合求采样时刻即时速度的新方法,在匀加速条件下对这3种方法进行了仿真实验,比较了测速误差。实验结果表明,角位移拟合法在整个速度范围内都能获得很高的测速精度和误差一致性。最后用CPLD对该方法加以实现,给出了Verilog硬件描述语言的设计程序和3种方法的实验结果比较。基于CPLD的实现方法电路简单,运行稳定可靠,处理速度快,为角位移拟合法提供了一种非常好的实现方法。     

基于Hilbert曲线和位置自调节法的图像版权保护算法

以小波的相关理论为基础,先把水印图像预置乱处理,对宿主图像直接进行小波包分解,之后将水印的低频部分和中高频部分分别采用Hilbert曲线扫描和位置自调节法嵌入到宿主图像中,嵌入强度可根据图像的内容自适应调节。通过实验观察,新算法在抗压缩和抗剪切性能有所提升,同时隐蔽性和抗噪能力也得到了较大改观,结果充分说明该算法是一种性能较为优良的图像版权保护算法。     

基于多圈电位器的云台控制系统设计

大多数云台不需要定位控制,但有些特殊的场合其监控需要云台的定位控制。定位是机电设备常用控制方式,大多采用开机复位的方式,即设备断电即失去了位置信号,通过上电复位来重新定义位置。另一种就是通过绝对值编码器来定义位置,但是其价格颇高。笔者提出用电位器替代绝对值编码器,用于在精度要求不是特别高的场合,是一种经济的定位方式。采用多圈一体化开度定位装置,即传感器（电位器）、电机和控制器集成在一起,很好地解决了结构问题,使得装置的使用变得非常方便。该多圈一体化开度控制器（专利号：ZL 201420123207.3）,可用于监控云台的定位等的控制。     

基于无传感器的PMSM电流控制策略的研究

提出一种新型的滑模观测器,并分别研究在4种不同的电流控制策略下,基于该新型滑模观测器的PMSM伺服系统的控制问题。该新型滑模观测器引进了Sigmoid函数作为控制函数用来抑制抖振,并根据PMSM的反电动势模型构建了反电势观测器来提取所需的连续信号,因此取消了传统的一阶低通滤波器和相角补偿环节。为了对电机的转子位置和转速进行更加精确的估算,引入了转子位置锁相环结构。在Matlab/Simulink平台基础上建立了4种不同的电流控制策略,基于新型滑模观测器PMSM无位置传感器三闭环控制系统仿真模型,分别对反电动势估算、速度估算、位置估算和突加负载扰动进行了仿真分析。仿真结果表明,该新型滑模观测器在4种不同的电流控制策略下,对电机转子位置和转速的估算、电磁转矩以及定子三相电流有着不同的影响,验证了该新型滑模观测器算法的可行性。     

基于硬件滤波电路的无刷直流电机转子位置辨识

反电动势过零检测是无刷直流电机无位置传感器控制中转子位置检测的主要方法之一,为消除PWM因素的影响,需要对转子位置检测电路进行滤波处理。本文采用硬件滤波器对反电动势过零检测电路进行滤波,既要考虑深度滤波带来的相移问题又要兼顾消除噪声的影响,分析滤波器的幅频特性和相频特性,根据反电动势过零检测指标要求设计滤波器参数,并用于无刷直流电机转子位置辨识和无位置传感器控制中。仿真结果和实验结果表明,所采用的滤波器及其参数能较好地检测出转子位置,可以明显提高无位置传感器无刷直流电机驱动系统的控制性能。     

对策论在雷达阵地综合防护效能分析中的应用

针对雷达阵地的防护特点,运用对策论的基本原理探索雷达阵地综合防护效能分析问题.构建了雷达阵地综合防护效能分析指标体系,结合对策论建立了评估模型,并用实例检验该方法具有较好的应用价值.     

TH-PPM UWB通信系统多址性能研究

介绍了TH-PPM UWB信号,在AWGN信道和多用户干扰条件下对系统的性能进行了分析,包括误码率分析和系统所能接入的最大用户数,对其误码率进行了仿真.结果表明,随着接入用户数目的增加,系统误码率也增加,而增大重复码长度和脉冲重复时间则可降低系统误码率,但增加脉冲重复时间会降低信息传输速率.