ESA microgravity and microdynamics activities — An overview

Stark, H.; Stavrinidis, C.

doi:10.1016/0094-5765(94)90258-5

Cited by 12 publications

(6 citation statements)

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“…The microgravity environment of space stations has opened up a new frontier for experimental research in materials science, basic physics, life science, and biotechnology [ 1 ]. However, the conditions of acceleration-sensitive experiments are usually not satisfied because of the low-frequency and high-frequency micro-vibrations produced by gravity gradients, orbital maneuvers, attitude control, equipment operation, and astronaut activities in the space laboratory [ 2 , 3 , 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

Design and Analysis of a 2-DOF Electromagnetic Actuator with an Improved Halbach Array for the Magnetic Suspension Platform

Yang

Zhao

et al. 2022

Sensors

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For large bearing capacity and low current consumption of the magnetic suspension platform, a 2-DOF electromagnetic actuator with a new structure of halbach array is proposed to improve driving force coefficients. The structure and the working principle are introduced. An accurate sub domain model of the new structure is established to accurately and rapidly calculate the magnetic field distribution for obtaining the parameters and performance of the electromagnetic actuators. The analytical model results are verified by the finite element method. The force/torque model of the magnetic suspension platform is established based on the proposed 2-DOF electromagnetic actuator. Three position-sensitive detectors and six accelerometers are applied to perceive in real time the posture and vibration acceleration of the platform, respectively. Their hardware information is introduced and measurement models are established based on the layout. Finally, the electromagnetic characteristics of the proposed actuator are investigated and compared with the conventional counterpart by finite element analysis. The results show that the average magnetic field, 0.432T, horizontal and vertical force coefficient, 92.3 N/A and 30.95 N/A, and torque in x and z direction, 3.61 N·m and 8.49 N·m, of the proposed actuator are larger than those of the conventional one.

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Section: Introductionmentioning

confidence: 99%

Design and Analysis of a 2-DOF Electromagnetic Actuator with an Improved Halbach Array for the Magnetic Suspension Platform

Yang

Zhao

et al. 2022

Sensors

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“…Micro-vibration has been a dominant factor impairing space scientific experiments’ performance. It contaminates the microgravity environment and degrades the ideal working condition of sensitive payloads (Stark and Stavrinidis, 1994). The term micro-vibration refers to a low-level acceleration disturbance in the microgravity environment, with a wide frequency range (from direct current (d.c.) to 1 kHz) and small magnitude (1μg to 100mg, where g=9.8ms2) (Aglietti et al., 2004).…”

Section: Introductionmentioning

confidence: 99%

System integration and control design of a maglev platform for space vibration isolation

Gong

Yue

Gao

et al. 2019

Journal of Vibration and Control

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Micro-vibration has been a dominant factor impairing the performance of scientific experiments which are expected to be deployed in a micro-gravity environment such as spacelab. The micro-vibration has serious impact on the scientific experiments requiring quasi-static environment. Therefore, we proposed a maglev vibration isolation platform (MVIP) operating in six degrees of freedom (DOF) to fulfill the environmental requirements. In view of non-contact and large stroke requirement for micro-vibration isolation, an optimization method was utilized to design the actuator.Mathematical models of actuator's remarkable nonlinearity was established, so that its output can be compensated according to floater's varying position and system's performance may be satisfied. Furthermore, aiming to adapt to an energy-limited environment such as spacelab, an optimum allocation scheme was put forward.Considering actuator's nonlinearity, accuracy and minimum energy-consumption can be obtained simultaneously. In view of operating in six DOF, methods for nonlinear compensation and system decoupling were discussed, the necessary controller were also presented. Simulation and experiments validate system's performance. With a movement range of 10×10×8 mm and rotations of 200 mrad, the decay ratio of -40 dB/Dec between 1-10 Hz was obtained under close-loop control.

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“…Despite the low amplitude of these disturbances they can significantly degrade the performance of sensitive instruments, and there has been a growing interest 1,2 in the application of both active and passive control techniques to this problem. These vibrations are produced by the functioning of on board equipment ͑sources͒ such as reaction wheels, gyroscopes, thrusters, electric motors, pumps, switches, and all types of mechanisms, and they propagate through the satellite structure ͑Fig.…”

Section: Introductionmentioning

confidence: 99%

A modeling technique for active control design studies with application to spacecraft microvibrations

Aglietti

Gabriel

Langley

et al. 1997

The Journal of the Acoustical Society of America

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Microvibrations, at frequencies between 1 and 1000 Hz, generated by on board equipment, can propagate throughout a spacecraft structure and affect the performance of sensitive payloads. To investigate strategies to reduce these dynamic disturbances by means of active control systems, realistic yet simple structural models are necessary to represent the dynamics of the electromechanical system. In this paper a modeling technique which meets this requirement is presented, and the resulting mathematical model is used to develop some initial results on active control strategies. Attention is focused on a mass loaded panel subjected to point excitation sources, the objective being to minimize the displacement at an arbitrary output location. Piezoelectric patches acting as sensors and actuators are employed. The equations of motion are derived by using Lagrange's equation with vibration mode shapes as the Ritz functions. The number of sensors/actuators and their location is variable. The set of equations obtained is then transformed into state variables and some initial controller design studies are undertaken. These are based on standard linear systems optimal control theory where the resulting controller is implemented by a state observer. It is demonstrated that the proposed modeling technique is a feasible realistic basis for in-depth controller design/evaluation studies.

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ESA microgravity and microdynamics activities — An overview

Cited by 12 publications

References 0 publications

Design and Analysis of a 2-DOF Electromagnetic Actuator with an Improved Halbach Array for the Magnetic Suspension Platform

Design and Analysis of a 2-DOF Electromagnetic Actuator with an Improved Halbach Array for the Magnetic Suspension Platform

System integration and control design of a maglev platform for space vibration isolation

A modeling technique for active control design studies with application to spacecraft microvibrations

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