Research on Attitude Adjustment Method of Suspension Coil in Joule Balance
GAN Wei1,ZENG Tao1,BAI Yang2,LI Zheng-kun2,WANG Yue2
1. College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou, Zhejiang 310018, China
2. National Institute of Metrology, Beijing 100029, China
Abstract：Alignment error will be introduced if the initial pose of the suspension coil is not ideal. The precision control of the horizontal position of the coil center can be realized with the help of a two-axis high-precision displacement platform. However, due to the coupling effect among the 3-link adjustment mechanisms of coil attitude adjustment, it is difficult to achieve accurate attitude adjustment. Based on the mathematical model between the initial pose and parasitic displacement of the suspension system of Joule balance, the absolute horizontal position of the coil was determined. The attitude control experiment was carried out near the absolute horizontal position of the coil, and the discrete state space model of the attitude control system of the suspension coil was obtained by using the recursive lLeast square method. On this basis, a model predictive control strategy based on state space was established to approximate adjust the attitude of the suspension coil to the absolute horizontal. The 3-link control accuracy was better than 0.25μm, and the attitude control accuracy was better than 1μrad.
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2023, Vol. 44 
