ROBOT'S MOTION ERROR AND ONLINE COMPENSATION BASED ON FORCE SENSOR

Robot＇s dynamic motion error and on-line compensation based on multi-axis force sensor are dealt with.It is revealed that the reasons of the error are formed and the relations of the error are delivered.A motion equation of robot＇s termination with the error is established,and then,an error matrix and an error compensation matrix of the motion equation are also defined.An on-line error＇s compensation method is put forward to decrease the displacement error,which is a degree of millimeter,shown by the result of simulation of PUMA562 robot.

On-Machine Measurement of the Straightness and Tilt Errors of a Linear Slideway Using a New Four-Sensor Method

Although there are some multi-sensor methods for measuring the straightness and tilt errors of a linear slideway, they need to be further improved in some aspects, such as suppressing measurement noise and reducing precondition.In this paper, a new four-sensor method with an improved measurement system is proposed to on-machine separate the straightness and tilt errors of a linear slideway from the sensor outputs, considering the influences of the reference surface profile and the zero-adjustment values. The improved system is achieved by adjusting a single sensor to di erent positions. Based on the system, a system of linear equations is built by fusing the sensor outputs to cancel out the e ects of the straightness and tilt errors. Three constraints are then derived and supplemented into the linear system to make the coe cient matrix full rank. To restrain the sensitivity of the solution of the linear system to the measurement noise in the sensor outputs, the Tikhonov regularization method is utilized. After the surface profile is obtained from the solution, the straightness and tilt errors are identified from the sensor outputs. To analyze the e ects of the measurement noise and the positioning errors of the sensor and the linear slideway, a series of computer simulations are carried out. An experiment is conducted for validation, showing good consistency. The new four-sensor method with the improved measurement system provides a new way to measure the straightness and tilt errors of a linear slideway, which can guarantee favorable propagations of the residuals induced by the noise and the positioning errors.

System modeling based measurement error analysis of digital sun sensors

Stringent attitude determination accuracy is required for the development of the advanced space technologies and thus the accuracy improvement of digital sun sensors is necessary.In this paper,we presented a proposal for measurement error analysis of a digital sun sensor.A system modeling including three different error sources was built and employed for system error analysis.Numerical simulations were also conducted to study the measurement error introduced by different sources of error.Based on our model and study,the system errors from different error sources are coupled and the system calibration should be elaborately designed to realize a digital sun sensor with extra-high accuracy.

Simulation of Current Measurement Using Magnetic Sensor Arrays and Its Error Model

Magnetic sensor arrays are proposed to measure electric current in a non-contact way. In order to achieve higher accuracy, signal processing techniques for magnetic sensor arrays are utilized. Simulation techniques are necessary to study the factors influencing the accuracy of current measurement. This paper presents a simulation method to estimate the impact of sensing area and position of sensors on the accuracy of current measurement. Several error models are built up to support computer-aided design of magnetic sensor arrays.

A New Study to Compensate Dynamic Measuring Error of Serial Multiple Degree of Freedom（DOF） Strain Gauge Force Sensor

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Analysis of signal-obtaining error factor of sensor in gyro

The digital signal-obtaining for gyroscope is given. The single optic-fiber sensor via modulating intensity of light is used as measuring component . The influence on static transmission properties resulting from the special working environment (e.g. cryogenic and vacuum) ,the measure error because of the reflector shape of rotor,the abnormity of facula from sensor caused by the existence of engraving error,and the fixing error of sensor and the error of machine tool’s initial lignment are investigated. The mathematic model in every condition is founded, the simulation and relative experiments are done and the outcome is analyzed. The mathematic model and method of compensating technology are studied and some relative experiments are made. The result of study is useful to improvement of the signal-obtaining system.

10-Bit Single-Slope ADC with Error Calibration for TDI CMOS Image Sensor

A 10-bit single-slope analog-to-digital converter (ADC) for time-delay-integration CMOS image sensor was proposed. A programmable ramp generator was applied to accomplish the error calibration and improve the linearity. The ADC was fabricated in a 180 nm 1P4M CMOS process. Experimental results indicate that the differential nonlinearity and integral nonlinearity were 0.51/-0.53 LSB and 0.63/-0.71 LSB, respectively. The sampling rate of the ADC was 32 kHz.

Sensor array calibration for uniform rectangular array in presence of mutual coupling and sensor gain-and-phase errors

The sensor array calibration methods tailored to uniform rectangular array(URA)in the presence of mutual coupling and sensor gain-and-phase errors were addressed.First,the mutual coupling model of the URA was studied,and then a set of steering vectors corresponding to distinct locations were numerically computed with the help of several time-disjoint auxiliary sources with known directions.Then,the optimization modeling with respect to the array error matrix(defined by the product of mutual coupling matrix and sensor gain-and-phase errors matrix)was constructed.Two preferable algorithms(called algorithm I and algorithm II)were developed to minimize the cost function.In algorithm I,the array error matrix was regarded as a whole parameter to be estimated,and the exact solution was available.Compared to some existing algorithms with the similar computation framework,algorithm I can make full use of the potentially linear characteristics of URA's error matrix,thus,the calibration precision was obviously enhanced.In algorithm II,the array error matrix was decomposed into two matrix parameters to be optimized.Compared to algorithm I,it can further decrease the number of unknowns and,thereby,yield better estimation accuracy.However,algorithm II was incapable of producing the closed-form solution and the iteration operation was unavoidable.Simulation results validate the excellent performances of the two novel algorithms compared to some existing calibration algorithms.

Research on Consistency Judgement of Indication Error for Calibration Result of Humidity Sensor in Meteorology

In order to solve the lack of relevant evaluation research on the accuracy of HMP155A humidity sensor calibration results in the past, this paper designs the corresponding experimental scheme, and obtains the corresponding calibration results according to the experimental scheme;Then the measurement uncertainty of the indication error in the calibration results is evaluated by GUM, and the corresponding extended uncertainty U95 is obtained. Finally, according to the requirements of JJF1094-2016 characteristic evaluation of measuring instruments, combined with the calibration results and the actual situation of U95, the conformity of the indication error of calibration is determined. The result is that each calibration point of the sensor meets the requirements of conformity determination and is within the qualified range. This research effectively makes up for the blank of the previous research on the conformity determination of the indication error of the calibration results and has strong theoretical and practical significance.

旋变二次谐波测角误差自校正

旋变幅值误差和正交误差在角速度频谱上表现为旋变转频的二次谐波,是旋变测角误差的主要来源,影响伺服系统角速度控制精度和稳定度。本文提出了一种基于特征频率参考的二次谐波误差自校正方法。首先,分析旋变测角误差产生的机理,获知其幅值误差和正交误差的互不相关性,并证明对旋变输出信号进行幅值调整和相位差调整可实现二次谐波误差校正。然后,在旋变和旋变数字信号转换器(Resolver-to-Digital Converter,RDC)之间设计基于比例放大的幅值校正器和基于交叉调节的相角校正器。最后,根据误差信号在线性控制系统中特征频率不变的特性,对伺服系统进行匀速控制,以角速度频谱中二次谐波频率的幅值为参考基准,分别调整幅值校正器和相角校正器,校正二次谐波误差。实验结果表明:本方法可将旋变二次谐波测角误差幅值降低78.5%,伺服系统速率波动量降低40.5%。本方法实现了旋变二次谐波测角误差的自校正,大幅提升了旋变的测角精度和伺服系统的转速控制稳定度。

基于无迹卡尔曼滤波算法的喷涂机器人末端位姿补偿系统

喷涂建筑机器人在进行建图时无法将地面平整度的信息包含在地图中。当机器人按照所建地图运行时,由于地面信息的缺失,喷涂建筑机器人工作末端的喷涂夹具无法与墙面平行。为补偿喷涂夹具相对于墙面之间的位姿误差,提出一种基于无迹卡尔曼滤波的多传感器融合的喷涂夹具位姿补偿方法:以位移测量传感器测得的数据构建夹具位姿的状态方程,以陀螺仪测得的数据构建夹具位姿测量方程;利用无迹卡尔曼滤波算法获得夹具姿态的最优估计并将其传递给机器人,从而实现对喷涂夹具位姿误差的补偿。搭建实验平台验证了误差补偿系统的可行性。实验结果表明,误差补偿后的喷涂夹具相对于墙面之间的角度误差减小至0.005°。

射电望远镜基于座架温度的热致指向误差建模

温度是影响高频大型射电望远镜性能的关键因素之一。以天马望远镜(TMRT)为例,研究了座架节点温度与天线指向之间的关系,提出了基于节点温度的指向误差修正模型构建方法。将指向误差视为座架节点温度的线性组合,以节点的温度灵敏度作为特征条件优化自变量的个数,将北极附近源2344+8226的指向测试结果作为样本集,与自变量简化前后的温度模型的效果进行对比。同时,这两种温度模型也进行了有限元分析验证,模型计算和有限元分析结果都与样本集相吻合。为了验证模型的通用性,对比分析了模型简化前后在4个季度的表现,结果表明简化后的温度模型预测效果更佳。建立的基于节点温度的指向误差修正模型的快速计算结果,也为座架热致指向误差实时修正提供数据支持。

面向无线传感网络的同步时钟技术研究

考虑到传统的时钟同步技术在信息交互过程中产生的延迟具有不确定性,为了消除其对时钟同步的影响,提出了面向无线传感网络的同步时钟技术研究。通过对任意一个网络节点在真实物理时间的本地时间进行变换处理,构建无线传感网络的线性时钟模型,根据高斯分布所具有的加减特性,计算两个连续同步轮次的动态响应时间差值,在离散形式下,构建无线传感网络观测模型。通过计算无线传感网络时钟差值的均值,得到无线传感网络节点的时间戳,将无线传感网络节点数据交互误差补偿的目标函数转换成向量的形式,补偿无线传感网络节点数据交互误差,实现无线传感网络的时钟同步处理。实验结果表明,在微秒级延迟下,该技术的同步精度仍较高,可以有效消除网络信息延迟的不确定性对同步时钟的影响。

基于电涡流效应的绝对式直线位移传感器误差分析及抑制方法研究

基于电涡流效应的绝对式直线位移传感器具有结构简单、分辨率高、响应速度快和抗干扰能力强的特点。相比于增量式直线位移传感器,该类型的传感器不仅不受断电的影响,还能实现更加快速和精确的绝对定位。但是,传感器制造、安装及电信号处理等环节处理不理想会产生无效电动势,带来对极内的1次、2次和4次误差。针对上述问题,使用信号补偿的方式抑制1次和2次误差,采用空间移相的方式消除感应信号中的3次谐波,以此抑制4次误差。对优化后的传感器进行误差抑制实验,验证了误差来源分析的正确性以及抑制方法的有效性。实验表明:误差抑制后的传感器节距内误差峰峰值由32μm优化为6μm,性能大幅度提升。

基于拼接技术的大量程绝对式直线时栅位移传感器自校准方法研究

针对大量程直线位移传感器扩展测量范围和实现绝对定位互相矛盾的问题,在其应用场合缺乏高效安装高精度参考器件的条件,导致难以频繁在线校准以保持其测量精度,基于拼接技术提出一种适用于直线时栅位移传感器的误差延拓自校准新方法。,将复杂的大量程绝对式测量拆分为单段栅尺上的绝对位移测量和栅尺拼接后的绝对位置判断;将绝对位置数据作为位置判断依据并构建双测头结构,实现接缝处感应信号的平滑过渡;利用原生的双测头结构获得定距测量序列,结合误差延拓法构建周期误差函数,再使用快速傅里叶变换获得测量序列幅度谱重构误差函数。为了验证上述方法的可行性和有效性,制作了单段栅尺长度为600 mm的传感器样机进行实验。结果表明,2段栅尺拼接后在量程903 mm内能够实现绝对位置测量;采用自校准方法后传感器单周期内平均误差峰值从2.00μm降至0.59μm,误差补偿效果为70.50%;大量程误差峰值从18.93μm降至0.75μm,误差补偿效果为96.04%;此外,通过校准效果对比实验证明了误差延拓自校准方法优于基于傅里叶谐波补偿的比较校准法,误差校准效果提升约76.20%。

基于末端触觉传感器的智能机器人压力补偿

末端触觉是智能机器人实现对外部环境做出直接反应的必需媒介。触觉传感器的弹性层易导致表面接触压力测量结果出现偏差,降低机械手的抓取力度的合理性。提出智能机器人末端触觉传感器压力误差补偿方法。建立触觉传感器三维力学模型,分析表面接触应力与弹性层之间的关系,得到传感器压力特征;计算弹性层的低通效应值,通过传感器测量值推理得到表面压力值,利用线性迭代反卷积算法对压力误差补偿。实验结果表明,研究方法应用下,压力误差补偿的均方误差接近于10-3,精度与理想效果更接近,上述方法获取的传感器对不同大小作用力的电学响应结果与实际数据具有较高一致性。

基于物理水平基准的组合式高程测量方法

针对空间坐标点相对于测量基准的高程测量准确性问题,提出一种基于物理水平基准的组合式高程测量方法。利用激光三角测量原理及其测量光路的几何特性,搭建了物理水平基准的高程测量系统,在朗伯散射光场中,分析了倾角变化对激光光能质心偏移量的影响,建立了相应的误差修正模型,利用倾角传感器实现了高程测量的倾角误差补偿,自主研制了标定平台对本文提出的高程测量系统进行标定验证试验。结果表明:本文提出的组合式高程测量方法能够在500 mm测量量程下将重复性测量误差控制在±20μm的波动范围内,相较于单一激光位移传感器测量方式,其组合式高程测量误差波动量大幅度降低,能够适应空间坐标点在任意姿态下的精准测量,有效改善激光位移传感器在高程测量领域的性能,使其测量结果更为真实有效。

基于交叉变异PSO算法的形貌测量系统误差补偿

触针表面形貌测量系统具有高精度、高分辨率、稳定可靠和动态特性好等优点,在生产和科研中发挥着重要作用。但其杠杆结构造成的非线性误差,在大量程测量时会显著增大误差,影响测量精度。本文基于粒子自身的亲和力和浓度选择交叉变异提出一种新型粒子群算法,显著提高了粒子群算法的迭代速度和收敛精度。基于此粒子群算法可实现对触针表面形貌测量系统的非线性误差补偿,有效避免局部收敛,提高了补偿精度。经实验验证,通过高精度标准球冠进行标定测量,补偿误差在±0.5μm以内。

地面气象测温传感器设计及实验研究

地面气象测温传感器受太阳辐射的影响,测量时其辐射误差可达1 K量级。针对此问题,设计了一种新型地面测温传感器结构。使用计算流体动力学(computational fluid dynamics,CFD)方法将多个气象参数下的仪器辐射误差进行量化,采用粒子群优化支持向量机算法对其结果进行拟合,得到辐射误差修正方程。以076B强制通风仪器的测量值作为温度基准开展场外实验。结果表明,设计的地面气象测温传感器经修正方程修正后的测量结果与温度基准的均方根误差(root mean square error,RMSE)和平均绝对误差(mean absolute error,MAE)分别为0.029 K和0.027 K,可将辐射误差保持在0.05 K以内。