光电轴角编码器光电信号正交偏差的 测量和补偿方法

高精度光电轴角编码器细分误差中莫尔条纹光电信号的正交性偏差影响最大。采用锁相环测量偏差 软件补偿的方法对正交性偏差进行自动校正和补偿,效果明显。在补偿过程中,以正弦信号为基准信号,对余弦信号进行计算补偿,得到一个新的余弦信号来代替硬件中原有的余弦原始信号,使新的余弦信号与正弦信号正交,同时包含了余弦原始信号的所有信息。实验结果表明,在一定偏差范围内,经过补偿后,信号的正交性偏差得以明显降低。     

光电轴角编码器光电信号正交偏差的测量和补偿方法

高精度光电轴角编码器细分误差中莫尔条纹光电信号的正交性偏差影响最大。采甩锁相环测量偏差＋软件补偿的方法对正交性偏差进行自动校正和补偿,效果明显。在}r偿过程中,以正弦信号为基准信号,对余弦信号进行计算补偿,得到一个新的余弦信号来代替硬件中原有的余弦原始信号,使新的余5玄信号与正弦信号正交,同时包含了余弦原始信号的所有信息。实验结果表明,在一定偏差范围内,经过补偿后,信号的正交性偏差得以明显降低。     

一种新的光栅传感器信号相位补偿算法的设计

为了保证光栅传感器的分辨率的提高,减小细分算法的误差,文中提出了一种新的相位检测与补偿的处理方法.该方法主要采用易于硬件实现的CORDIC算法来实现,用CORDIC算法的向量模式来检测两路信号的相位并得到其相位偏差,再用其旋转模式对有相位偏差的信号进行补偿.补偿过程中,以正弦信号为基准,对有相位偏差的余弦信号进行补偿.仿真实验表明,该算法可使相位偏差得到有效补偿,补偿后的偏差不超过补偿前的2％.     

光电轴角编码器细分误差的Matlab仿真评估方法

本文根据影响编码器光电信号的因素,利用实测的Lissajous图及Matlab超强的数据处理功能,提出利用Matlab仿真评估编码器细分误差的方法。针对编码器莫尔条纹原始信号的正弦性、正交性、等幅性及含直流电平这几种典型特征,利用Matlab仿真对产生误差的原因进行单项分析评估。     

光电轴角编码器细分误差的Matlab仿真评估方法

本文根据影响编码器光电信号的因素,利用实测的Lissaious图及Matlab超强的数据处理功能,提出利用Matlab仿真评估编码器细分误差的方法.针对编码器莫尔条纹原始信号的正弦性、正交性、等幅性及含直流电平这几种典型特征,利用Matlab仿真对产生误差的原因进行单项分析评估.     

栅式电容位移传感阵列信号正交性偏差的智能补偿方法

本文提出一种栅式电容位移传感阵列信号正交性偏差的补偿方法和实现方式.分析传感阵列X-Y方向线性位移信号正交性偏差产生的原因,建立偏航角影响下的信号正交性偏差模型,利用互相关检测原理,构造了栅式电容位移传感阵列信号正交性偏差补偿新方法.实验结果表明,传感阵列正交性偏差跟随偏航角位移θ从为0.2°变化为0.4°,0.8°和2.0°时有显著增大,采用互相关补偿法后保证了X-Y线性位移信号的非线性度维持在0.32％,0.29％,0.24％和0.07％之间,对比直接求解法有大幅的降低,基本消除了正交性偏差对X-Y方向线性位移测量的影响,测量稳定性得到显著改善.     

麦克劳林级数法求取光电编码器转子位置算法

由于制作工艺使得光栅线数受到限制,增量式光电编码器每转一周输出的脉冲数量有限,已无法满足高精度伺服系统的控制性能要求.根据正余弦编码器输出的正弦信号,将一个周期分为八个小区间,继而根据麦克劳林近似公式,提出反向数据拟合方法直接拟合出正弦信号对应的相位值,进一步得到转子的精确位置,使得计算精度高、运行速度快,解决了电机极低速运行时角度精度低的问题.搭建了实际电路及测试平台,得到了与理论分析相一致的效果.     

光电编码器滤波技术研究

在高精度光电跟踪系统中,光电编码器被用来测量转速.但是由于测量会引入误差,给测量所得的速度信号带来很大噪声.为了消除噪声对速度信号精度的影响,采用FIR滤波器对速度信号进行滤波处理,并使用最小二乘法对延时进行补偿,提高速度信号的质量,以便进行实时控制.其中FIR采用DA算法在FPGA中实现,以减少计算延时.实验结果表明,该方法不仅可以提高速度信号质量,而且不会产生延时,可以应用于实时控制系统中.     

高精度光电编码器信号补偿技术的研究进展

近年来,由于多领域对于旋转控制需要的增长,光电编码器获得了广泛的应用,同时也对光电编码器的测角精度和分辨力提出了更高的要求。指出了光电信号补偿技术的发展为光电编码器精度的提高提供了重要保障;介绍了光电编码器的原理及衡量光电信号质量的4项指标;从此4项指标出发,总结了国内外的信号自适应补偿技术的研究现状;最后,分析了现有补偿方法的优点和存在的限制,展望了光电编码器信号补偿方法的发展趋势。     

光电轴角编码器细分误差动态评估方法

介绍了一种光电轴角编码器细分误差动态评估的方法.光电轴角编码器匀速转动时,采集相位差为π/2的两路精码正弦光电信号,然后对采集到的光电信号进行等转角数据处理及谐波分析,从而求出光电信号波形参数,波形参数确定后可以建立波形方程.再将波形方程代入到细分误差的计算公式求出细分误差.试验结果表明,该方法是有效的.     

Improve the robot calibration accuracy using a dynamic online fuzzy error mapping system.

Traditional robot calibration implements model and modeless methods. The compensation of position error in modeless method is to move the end-effector of robot to the target position in the workspace, and to find the position error of that target position by using a bilinear interpolation method based on the neighboring 4-point's errors around the target position. A camera or other measurement devices can be utilized to find or measure this position error, and compensate this error with the interpolation result. This paper provides a novel fuzzy interpolation method to improve the compensation accuracy obtained by using a bilinear interpolation method. A dynamic online fuzzy inference system is implemented to meet the needs of fast real-time control system and calibration environment. The simulated results show that the compensation accuracy can be greatly improved by using this fuzzy interpolation method compared with the bilinear interpolation method.     

Topology preserving top-down compression of 2D vector fields using bintree and triangular quadtrees

We present a hierarchical top-down refinement algorithm for compressing 2D vector fields that preserves topology. Our approach is to reconstruct the data set using adaptive refinement that considers topology. The algorithms start with little data and subdivide regions that are most likely to reconstruct the original topology of the given data set. We use two different refinement techniques. The first technique uses bintree subdivision and linear interpolation. The second algorithm is driven by triangular quadtree subdivision with Coons patch quadratic interpolation. We employ local error metrics to measure the quality of compression and as a global metric we compute Earth Mover's Distance (EMD) to measure the deviation from the original topology. Experiments with both analytic and simulated data sets are presented. Results indicate that one can obtain significant compression with low errors without losing topological information. Advantages and disadvantages of different topology preserving compression algorithms are also discussed in the paper.     

Positioning of a mobile robot based on odometry and a new ultrasonic LPS

Odometry is a method that calculates the position and heading angle of a mobile robot using encoders attached to the wheels of the robot. Errors in the position and heading angle in odometry continuously increase as the operating time and moving distance increase. The solution to overcome these accumulated errors is to periodically compensate with the external absolute position information. An ultrasonic local positioning system (LPS) consists of multiple ultrasonic transmitters located in the environment and an ultrasonic receiver. In this study, ultrasonic transmitters are in a line at one side, and four transmitters are grouped for a coverage area. In order to measure the time of flights (TOFs) for an ultrasonic signal, the receiver predicted the transmitted time from each transmitter using a hyperbolic model. Four transmitters emit ultrasonic signals sequentially, and then the receiver calculates the position using the present measured distance and the pre-measured distance. In order to extend the distance that is measured, the receiver collects the ultrasonic signal and executes cross correlation with a sinusoidal signal. The measured distance data of the previous step causes the position error. This error is compensated for by the predicted distance data using a bilinear interpolation method. An extended Kalman filter is designed to combine odometry, a compass sensor, and an ultrasonic LPS. The proposed system provides reliable and accurate position and heading information, regardless of the operating time and moving distance.     

一种改进的基于离散余弦变换的声音压缩算法

摘要：声音压缩传输是异常声音检测系统中的重要模块。针对现有算法不能满足系统实时性要求的缺陷,提出一种采用角度误差限定分段拟合和离散余弦变换(DCT)的声音压缩算法。该算法先设置合理的角度误差,从时域波形的第一个采样点开始按照几何夹角和限定的角度误差逐点判断是否可以压缩,分段模拟信号波形,然后采用传统的基于离散余弦变换算法,选取合适的阈值再次进行压缩。实验结果表明,与传统的声音压缩算法相比,提出的算法在压缩效果上有较明显的改善。     

基于频差修正的余弦信号频率估计算法

针对余弦振动信号的频率高精度估计需求,提出了一种基于频差修正的频率估计算法.对连续时间信号进行采样后,使用Candan算法估计出频差,运用频差对信号的频率进行修正.对修正后的信号使用Liang算法再次进行频偏估计.最后将2次估计得到的频率值相加求得最终估计频率.通过频差修正,避免了Candan算法因插值方向错误和Liang算法自身特点导致估计精度降低的问题,虽然增加了计算量,但并不影响信号实时处理.仿真结果表明:在相对频偏为任意值的情况下,改进算法的频率估计均方误差接近克拉美罗下限(CRLB),性能优于现有频率估计算法.     

基于捷联惯性导航的矿用单轨吊机车定位算法

针对煤矿井下单轨吊机车常用定位方法存在定位精度低和定位成本高的问题,提出了一种基于捷联惯性导航的矿用单轨吊机车定位算法。采用九轴惯性测量单元(IMU)采集机车加速度数据,并对加速度数据进行限幅滤波和去零偏等预处理,解算并输出姿态角和加速度值;采用方向余弦矩阵法滤除加速度数据中所含的重力分量,消除该分量对数据的干扰;利用加速度变化率阈值法和零速修正法修正稳态误差,使稳态加速度和速度更接近真实值;采用Lagrange插值多项式测距法测量单轨吊机车的行驶距离,并利用测距结果定时修正法来补偿测距误差,根据机车的起点和行驶距离实现定位。实验结果表明,当车辆行程为30.8 m时,测距误差基本在0.65 m以内,可以达到高精度、低成本的定位要求。     

卫星移动通信信号处理同步技术研究

卫星移动通信信号处理同步技术很大程度上决定了通信的质量。针对卫星移动通信系统中突发信号符号长度短、独特码少的特点,对传统的基于最大似然准则线性相位内插相位估计算法和二次插值快速傅立叶变换频偏估计算法进行了研究,进行了线性相位内插算法和二次插值快速傅立叶变换频偏估计算法机理分析;根据噪声平均化原则,提出了一种低导频段数据情况下改进的线性相位内插算法;利用数据段信息和导频段信息整体做频偏估计的方法,提高了导频段个数较少情况下的频偏估计精度;仿真与试验结果表明：改进的线性相位内插算法比传统算法相位同步性能更高,利用整帧数据做频偏估计精度更高,并满足卫星移动通信终端信号处理的要求。     

基于锁相环跟踪算法的高精度轴角-数字变换系统研究

针对传统高精度集成轴角-数字变换系统外围电路复杂、成本高的特点,提出一种基于锁相环跟踪算法的全数字式轴角-数字变换系统方案。利用TMS320F2812的PWM模块产生旋转变压器激磁信号,根据该激磁信号,旋转变压器输出差分正、余弦信号,采用高精度的外围独立采样模块AD7606采样该差分正、余弦信号,依据采样的差分正、余弦信号,基于TMS320F2812设计的锁相环跟踪算法计算电机磁极位置。将该轴角-数字变换系统应用于一台安装有电气误差为±10′的单极对旋转变压器的伺服同步电机,对其进行了实验研究。研究结果表明,该轴角-数字变换系统外围硬件电路简单、成本低,角度测量误差小于10.66′,实现了高精度的轴角-数字变换。     

Discriminant analysis and similarity measure

The cosine similarity measure is often applied after discriminant analysis in pattern recognition. This paper first analyzes why the cosine similarity is preferred by establishing the connection between the cosine similarity based decision rule in the discriminant analysis framework and the Bayes decision rule for minimum error. The paper then investigates the challenges inherent of the cosine similarity and presents a new similarity that overcomes these challenges. The contributions of the paper are thus three-fold. First, the application of the cosine similarity after discriminant analysis is discovered to have its theoretical roots in the Bayes decision rule. Second, some inherent problems of the cosine similarity such as its inadequacy in addressing distance and angular measures are discussed. Finally, a new similarity measure, which overcomes the problems by integrating the absolute value of the angular measure and the l_p norm (the distance measure), is presented to enhance pattern recognition performance. The effectiveness of the proposed new similarity measure in the discriminant analysis framework is evaluated using a large scale, grand challenge problem, namely, the Face Recognition Grand Challenge (FRGC) problem. Experimental results using 36,818 FRGC images on the most challenging FRGC experiment, the FRGC Experiment 4, show that the new similarity measure improves face recognition performance upon other popular similarity measures, such as the cosine similarity measure, the normalized correlation, and the Euclidean distance measure.     

弹载地磁测量系统的抗干扰设计

为了消除弹载地磁测量系统所受的矿山、电磁、金属等干扰,本文设计了充磁电路,消除强磁场对磁阻传感器的干扰;设计了滤波电路及合理的布线,消除高频干扰信号;再提出了误差识别补偿及看门狗设置算法,补偿了软硬磁干扰、零位误差、正交误差。转台试验与数据分析表明:各组合方法的采用,减少了干扰误差使姿态角测量精度达到1°以内,具有一定的工程价值。