scholarly journals Drag-free motion control of satellite for high-precision gravity field mapping

2003 ◽  
Author(s):  
B. Ziegler ◽  
M. Blanke
Keyword(s):  
Gravity Field ◽  
Motion Control ◽  
High Precision ◽  
Free Motion ◽  
Field Mapping

scholarly journals Variable step control to improve scanning speed of gene sequencing stage

2021 ◽  
pp. 002029402110022
Author(s):  
Xiaohua Zhou ◽  
Jianbin Zheng ◽  
Xiaoming Wang ◽  
Wenda Niu ◽  
Tongjian Guo
Keyword(s):  
Motion Control ◽  
High Precision ◽  
High Speed ◽  
Stable State ◽  
Gene Sequencing ◽  
Scanning Speed ◽  
Settling Time ◽  
Step Motion ◽  
Variable Step ◽  
Step Control

High-speed scanning is a huge challenge to the motion control of step-scanning gene sequencing stage. The stage should achieve high-precision position stability with minimal settling time for each step. The existing step-scanning scheme usually bases on fixed-step motion control, which has limited means to reduce the time cost of approaching the desired position and keeping high-precision position stability. In this work, we focus on shortening the settling time of stepping motion and propose a novel variable step control method to increase the scanning speed of gene sequencing stage. Specifically, the variable step control stabilizes the stage at any position in a steady-state interval rather than the desired position on each step, so that reduces the settling time. The resulting step-length error is compensated in the next acceleration and deceleration process of stepping to avoid the accumulation of errors. We explicitly described the working process of the step-scanning gene sequencer and designed the PID control structure used in the variable step control for the gene sequencing stage. The simulation was performed to check the performance and stability of the variable step control. Under the conditions of the variable step control where the IMA6000 gene sequencer prototype was evaluated extensively. The experimental results show that the real gene sequencer can step 1.54 mm in 50 ms period, and maintain a high-precision stable state less than 30 nm standard deviation in the following 10 ms period. The proposed method performs well on the gene sequencing stage.

scholarly journals Three years of high precision gravity measurements at the gravimetric station of Brasimone - Italy

1998 ◽  
Vol 41 (2) ◽  
Author(s):  
G. Casula
Keyword(s):  
Gravity Field ◽  
High Precision ◽  
Nuclear Power ◽  
Meteorological Data ◽  
Normal Modes ◽  
Superconducting Gravimeter ◽  
Mass System ◽  
Global Geodynamics ◽  
Local Gravity ◽  
Italian Apennines

From August 1995 up to now, at the Enea Research Center of Brasimone, in the Italian Apennines between Bologna and Florence (Italy: 44º07'N, 11º.07'E, 890 m height), the superconducting gravimeter GWR model TT70 number T015 has been continuously recording the variation of the local gravity field, in the frame of the Global Geodynamics Project. The gravimetric laboratory, being a room of the disused nuclear power plant of Brasimone, is a very stable site, free from noise due to human activities. Data blocks of several months of continuous gravity records have been collected over a time span of three years, together with the meteorological data. The gravimeter has been calibrated at relative accuracy better than 0.3% with the aid of a mobile mass system, by imposed perturbations of the local gravity field and recording the gravimeter response. The results of this calibration technique were checked by two comparison experiments with absolute gravimeters performed during this period: the first, in May 1994 with the aid of the symmetrical rise and fall gravimeter of the Institute of Metrology Colonnetti of Turin, and the second in October 1997 involving an FG5 absolute gravimeter of the Institute de Physique du Globe of Strasbourg. The gravimeter signal was analysed to compute a high precision tidal model for Brasimone site. Starting from a set of gravimetric and atmospheric pressure data of high quality, relative to 46 months of observation, we performed the tidal analysis using Eterna 3.2 software to compute amplitudes, gravimetric factors and phases of the main waves of the Tamura catalogue. Finally a comparison experiment between two of the STS-1/VBB broadband seismometers of the MedNet project network and the gravity records relative to the Balleny Islands earthquake (March 25, 1998) were analysed to look for evidence of normal modes due to the free oscillations of the Earth.

scholarly journals High-Precision XY Stage Motion Control of Industrial Microscope

2019 ◽  
Vol 66 (3) ◽  
pp. 1984-1992
Author(s):  
Li Hong Idris Lim ◽  
Dazhi Yang
Keyword(s):  
Motion Control ◽  
High Precision
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