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精密减速器检测仪测角误差补偿 被引量:1
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作者 裘祖荣 周磊 +1 位作者 薛洁 于振 《光学精密工程》 EI CAS CSCD 北大核心 2021年第11期2622-2631,共10页
针对圆光栅安装倾斜、光栅变形等因素造成的精密减速器检测仪测角系统精度降低,传统误差补偿方法采样点数受多面棱体工作面限制,导致补偿效果不足的问题,提出一种多数据关联的误差补偿方法。采用自准直仪结合正24面棱体对圆光栅测角误... 针对圆光栅安装倾斜、光栅变形等因素造成的精密减速器检测仪测角系统精度降低,传统误差补偿方法采样点数受多面棱体工作面限制,导致补偿效果不足的问题,提出一种多数据关联的误差补偿方法。采用自准直仪结合正24面棱体对圆光栅测角误差进行标定,通过改变多面棱体与圆光栅在周向方向上的相对位置,得到多组测角误差标定数据。利用误差谐波法对多组测量数据进行预处理,将不同组数据关联,并代入BP神经网络中训练,得到圆光栅测角误差模型。该方法无需计算补偿式,能够克服误差谐波法在样本点过多时易产生拟合震荡的问题。实验结果表明:本文所提出的补偿方法残差峰峰值在0.94″内,标准差为0.25″,分别减小至误差谐波法修正后的33.3%和37.9%,有效提高了圆光栅测角系统的精度,使减速器检测仪测角精度达到亚角秒级。 展开更多
关键词 精密减速器检测仪 圆光栅 自准直仪 误差谐波法 BP神经网络 多数据关联
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On the Error Estimate of the Harmonic B_z Algorithm in MREIT from Noisy Magnetic Flux Field
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作者 Qun CHEN Jijun LIU 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2014年第3期319-336,共18页
Abstract Magnetic resonance electrical impedance tomography (MREIT, for short) is a new medical imaging technique developed recently to visualize the cross-section conduc- tivity of biologic tissues. A new MREIT ima... Abstract Magnetic resonance electrical impedance tomography (MREIT, for short) is a new medical imaging technique developed recently to visualize the cross-section conduc- tivity of biologic tissues. A new MREIT image reconstruction method called harmonic Bz algorithm was proposed in 2002 with the measurement of Bz that is a single component of an induced magnetic flux density subject to an injection current. The key idea is to solve a nonlinear integral equation by some iteration process. This paper deals with the convergence analysis as well as the error estimate for noisy input data Bz, which is the practical situation for MREIT. By analyzing the iteration process containing the Laplacian operation on the input magnetic field rigorously, the authors give the error estimate for the iterative solution in terms of the noisy level 6 and the regularizing scheme for determining ABz approximately from the noisy input data. The regularizing scheme for computing the Laplacian from noisy input data is proposed with error analysis. Our results provide both the theoretical basis and the implementable scheme for evaluating the reconstruction accuracy using harmonic Bz algorithm with practical measurement data containing noise. 展开更多
关键词 MREIT Image reconstruction ITERATION Error estimate
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