功率天平准直误差软补偿关键技术研究

项目名称： 功率天平准直误差软补偿关键技术研究

项目编号： No.51507088

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 电工技术

项目作者： 李世松

作者单位： 清华大学

项目金额： 10.5万元

中文摘要： 功率天平是有望实现质量量子基准暨精确测量普朗克常数最重要的实验之一，但受准直误差制约，该实验的准确度提升遇到较大困难。为克服准直难题，申请项目提出一种全新的软补偿方法，以期通过引入修正量，减小准直测量误差并大幅降低实验系统对准直误差的敏感性。所提出的软补偿法难点在于：须通过对准直误差产生的机理进行深入分析，找到准确表征准直误差的数学模型，并能通过直接或间接测量，确定出准直误差表达式中的各个量。针对上述难点，申请项目拟：建立准确的准直误差数学模型，采用基于梯度线圈法测量功率天平磁体局部磁场，进而通过解耦拟合或保角变换确定整个磁体三维磁场分布；用双Kelvin电容传感器测定线圈的侧向运动速度；用三束相隔120度角的激光测定线圈沿水平轴旋转的角速度。上述测量量配合准直误差修正模型，有望最终实现对准直误差的实时软补偿，对推动质量量子基准这一世界性难题的进展具有重要意义。

中文关键词： 功率天平；普朗克常数；准直误差；误差补偿；国际单位制

英文摘要： The watt balance is one of the most focused experiments that can realize a new definition of the kilogram by precision measurement of the Planck constant. But due to the misalignment error, the accuracy of the watt balance is greatly limited. In order to overcome this problem, in this application, a novel misalignment error compensation method is proposed, in which the misalignment error would be reduced by introducing a correction term from related measurements. The difficulty for the compensation method is that the physical model of the misalignment error should be established with well determined quantities in the compensation model. Accordingly, we firstly aim to establish a mathematical model for the misalignment error. The three-dimensional contribution of the magnetic field in the watt balance is planned to be determined by partial measurement of the vertical profiles via a polynomial fitting. The horizontal velocity of the coil would be measured by a twin-Kelvin capacitor sensing system and the angular velocity of the coil will be determined by measurements of the vertical displacement of the coil at three different positions every 120 degrees. Based on a combination of the measurement and calculation, the misalignment error of the watt balance experiment can be determined and real-timely corrected, whic

英文关键词： watt balance；the Planck constant；misalignment error；error compensation；international system of units