Design and Control of a High Acceleration and High Precision Air Bearing Stage

Author(s):  
Yuntang Li ◽  
Jun Li ◽  
Chang Xu ◽  
Ling Wang
Author(s):  
J. Prado ◽  
G. Bisiacchi ◽  
L. Reyes ◽  
E. Vicente ◽  
F. Contreras ◽  
...  

A frictionless environment simulation platform, utilized for accomplishing three-axis attitude control tests in small satellites, is introduced. It is employed to develop, improve, and carry out objective tests of sensors, actuators, and algorithms in the experimental framework. Different sensors (i.e. sun, earth, magnetometer, and an inertial measurement unit) are utilized to assess three-axis deviations. A set of three inertial wheels is used as primary actuators for attitude control, together with three mutually perpendicular magnetic coils intended for desaturation purposes, and as a backup control system. Accurate balancing, through the platform’s center of mass relocation into the geometrical center of the spherical air-bearing, significatively reduces gravitational torques, generating a virtually torque-free environment. A very practical balancing procedure was developed for equilibrating the table in the local horizontal plane, with a reduced final residual torque. A wireless monitoring system was developed for on-line and post-processing analysis; attitude data are displayed and stored, allowing properly evaluate the sensors, actuators, and algorithms. A specifically designed onboard computer and a set of microcontrollers are used to carry out attitude determination and control tasks in a distributed control scheme. The main components and subsystems of the simulation platform are described in detail.


2021 ◽  
Author(s):  
Fabio Falconi ◽  
Claudio Porzi ◽  
Filippo Scotti ◽  
Giovanni Serafino ◽  
Antonio Malacarne ◽  
...  

Abstract In the last decade, the interest in software-defined ultra-wideband (UWB) and tunable radio frequency (RF) apparatuses with low size, weight, and power consumption (SWaP), has grown dramatically, pushed by the new 6G vision where, RF equipment shall enable a large number of fundamental applications as UWB communications, robot localization mapping and control and high precision radars, all of them contributing in revolutionizing our life style. Unfortunately, the coexistence of ultra-wideband and software-defined operation, tunability and low SWaP represents a big issue in the current RF technologies. In this article, to the best of our knowledge, the first example of a complete tunable software-defined RF transmitter with low footprint (i.e. on photonic chip) is presented exceeding the state-of-the-art for the extremely large tunability range of 0.5-50 GHz without any parallelization of narrower-band components and with fast tuning (<200micros). This first implementation, represents a breakthrough in microwave photonics.


2011 ◽  
Vol 1 (MEDSI-6) ◽  
Author(s):  
P. Marion ◽  
L. Ducotte ◽  
M. Nicola ◽  
H. P. van der Kleij ◽  
L. Eybert ◽  
...  

In high-accuracy motion stages, the positioning accuracy at the point of interest is strongly influenced by guiding errors: for translation motions, straightness errors and angular errors (pitch, yaw and roll); for rotation motions, axial, radial and tilt errors. When air bearings are used for guiding, the air film averages out local irregularities of bearings surfaces, which helps reduce guiding errors considerably. Some results obtained with air bearing precision systems designed and manufactured by specialized companies and tested at ESRF are described below.


Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2458
Author(s):  
Zizhou Sun ◽  
Yifan Dai ◽  
Hao Hu ◽  
Guipeng Tie ◽  
Chaoliang Guan ◽  
...  

The application of ultra-precision shaft parts is widely used, such as the spindle core of the air bearing spindle in ultra-precision machine tools. The precision of the spindle core is extremely high, and it is very difficult to obtain directly by traditional Computer Numerical Control (CNC) machine tools but is mostly obtained by manual grinding, whose machining efficiency is greatly limited. Based on the deterministic figuring theory, this paper focuses on the ultra-precision roundness, optimizing the filtering parameters of the measurement error data and studying the generation mechanism of the removal function morphology; the shape of the removal function is adjusted by combining the analysis of the figuring ability and positioning error. Finally, the optimized removal function is used on an experimental steel shaft, the average roundness convergence ratio is 72% higher than that of the original removal function, and the roundness reaches a 0.1 μm level. The result shows that a reasonable filtering of measured data and the removal function adjusted for the surface feature can improve the efficiency and precision of deterministic figuring on shaft parts.


2011 ◽  
Vol 17 (5-7) ◽  
pp. 1123-1127 ◽  
Author(s):  
Gang Sheng ◽  
Loulin Huang ◽  
Jen-Yuan Chang ◽  
Jizhong He ◽  
Suanlin Duan

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