Coupling efficiency improvement of light source with a convex lens for space charge managements

Li, Honggang; Yang, Quanfeng; Yang, Fangchao; Hong, Wei; Bai, Yanzheng; Zhou, Zebing

doi:10.1016/j.ijleo.2021.167999

Cited by 6 publications

(7 citation statements)

References 10 publications

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“…The polyetheretherketone gasket ensure the electrical insulation of the TM. • The ultraviolet light emitted from the external UV LED light source is coupled into the deep ultraviolet fiber [18], passes through the vacuum container, and finally enters the inside of the EH through the feedthrough. The LED A input illuminates the TM and the LED B input illuminates the EH.…”

Section: Apparatusmentioning

confidence: 99%

Continuous charge management scheme for TianQin

Pi¹,

Liu

et al. 2023

Class. Quantum Grav.

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TianQin is a proposed Chinese space-borne gravitational wave detection mission, which will consist of three Earth-orbiting spacecraft in equilateral triangle constellation. Due to the ``3 months on + 3 months off'' observation scheme, the continuous scientific observation period of TianQin is much shorter than LISA, it is highly preferred that other on-board operations, such as charge management, will not interrupt gravitational wave detection. This paper presents a torsion pendulum system on the ground to investigate the continuous discharge method in detail. It is found that the difference in surface characteristics between the test mass and the surrounding housing is the most critical to the success of the continuous discharge method. The effect of this difference on the continuous discharge process was evaluated in ground simulation experiments. And then based on our ground test, we also proposed a more feasible spatial continuous charge management strategy for TianQin.

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Section: Apparatusmentioning

confidence: 99%

Continuous charge management scheme for TianQin

Pi¹,

Liu

et al. 2023

Class. Quantum Grav.

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“…In both missions, low-pressure mercury vapor lamps were used to generate UV light for discharge at a wavelength of 254 nm. Compared to mercury lamps, UV LEDs offer advantages in terms of size, electrical power efficiency, light weight, and low power consumption, and have been tested and identified as a new light source for the CMS [24][25][26][27][28][29].…”

Section: Charge Management System (Cms)mentioning

confidence: 99%

“…In other words, a control law should be designed such that the state tracking error globally uniformly asymptotically tends to zero as t → ∞. First, the 'ideal' control solution can be defined as if the unknown parameters are known, as expressed in equation (27). Substituting equation (27) into equation (28) yields the system closed-loop dynamics:…”

Section: Mracmentioning

confidence: 99%

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Adaptive charge control for the space inertial sensor

Yang¹,

Hong²,

Li³

et al. 2023

Class. Quantum Grav.

Self Cite

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Inertial sensors are key components of gravitational wave observations and Earth geodesy missions. An inertial sensor includes an isolated free-floating test mass (TM) surrounded by capacitive electrodes and a housing frame (EH) to perform the relative-position measurement and control the TM in six degrees of freedom. Owing to galactic cosmic rays (GCRs) and solar energetic particles (SEPs), many additional accelerations are introduced through the Coulomb interaction between charged TMs and their surrounding conducting surfaces. Thus, the TM charge control is critical in space-based missions. A contact-free and ultraviolet (UV) light-based charge management system (CMS) was developed to reduce charge-induced noises acting on the TMs and minimize force disturbances that can perturb measurements or interrupt science tasks. However, the operating environment for space charge control is full of uncertainties and disturbances. Physical parameters in the discharging process are rarely measured and will vary owing to changes in solar activity, temperature, and so on. The unpredictability and variability of these parameters affects the CMS performance in long-term space missions and must be evaluated or eliminated. This paper presents a simplified physical model for the discharge process based on electron exchange between the TM and the opposing EH. Subsequently, a model reference adaptive control (MRAC) is proposed for the CMS with parametric uncertainties to maintain the TM charge below a certain level and improve its robustness. The simulation results show that the MRAC can automatically adjust control parameters to eliminate the effect of the variability of the aforementioned physical parameters, and the control precision can reach 0.1 mV under uncertainties, which is superior to that of a classic proportional-integral-derivative controller. This study demonstrated the effects of adaptive charge control and its potential for actual applications.

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“…Due to the complexity of the space environment, CMSs require high reliability, low power consumption, and convenient driving light sources [8]; AlGaN-based UV light emitting diodes (LEDs) meet these requirements. Therefore, in recent years, extensive research has been carried out on their space environment adaptation [9,10], lifetime [11], optical coupling methods [12], spectral stability [13], and charge management technologies based on these advancements [14][15][16]. However, the accurate modeling of interdependent operating characteristics, as well as the suppression of noise interference and model uncertainty in the optical output link through control methods, are often neglected in these studies.…”

Section: Introductionmentioning

confidence: 99%

Photo-Electro-Thermal Model and Fuzzy Adaptive PID Control for UV LEDs in Charge Management

Wang

Zhi

et al. 2023

Sensors

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Inertial sensors can serve as inertial references for space missions and require charge management systems to maintain their on-orbit performance. To achieve non-contact charge management through UV discharge, effective control strategies are necessary to improve the optical power output performances of UV light sources while accurately modeling their operating characteristics. This paper proposes a low-power photo-electro-thermal model for widely used AlGaN-based UV LEDs, which comprehensively considers the interaction of optical, electrical, and thermal characteristics of UV LEDs during low-power operations. Based on this model, an optical power control system utilizing a fuzzy adaptive PID controller is constructed, in which a switch is introduced to coordinate the working state of the controller. Thus, the steady-state performance is effectively improved while ensuring dynamic performance. The results show that the proposed model has an average prediction error of 5.8 nW during steady-state operations, and the fuzzy adaptive PID controller with a switch can reduce the fluctuation of light output to 0.67 nW during a single discharge task, meeting the charge management requirements of high-precision inertial sensors.

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Coupling efficiency improvement of light source with a convex lens for space charge managements

Cited by 6 publications

References 10 publications

Continuous charge management scheme for TianQin

Continuous charge management scheme for TianQin

Adaptive charge control for the space inertial sensor

Photo-Electro-Thermal Model and Fuzzy Adaptive PID Control for UV LEDs in Charge Management

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