Solar Wing Research Articles

Progress in Zero-gravity Unloading Test and System Research of Solar Wing

Aim: The solar wing undertakes the important task of providing energy for spacecraft. The deployment test of the solar wing in a zero gravity environment using a zero gravity system on the ground is an important link to ensure the safe and stable deployment of the solar wing in space. This article briefly describes the development process and research progress of solar wings, introduces the ground zero gravity test methods and test platforms for solar wings, including some patents for improving the ground zero gravity test platform for solar wings, and points out some urgent problems that need to be solved in the zero gravity unloading test and system at present. Background: The solar wing needs to be deployed in the weightlessness environment of space before working. Objective: The objective of this study is to summarize the zero gravity experimental methods and systems of solar wings, introduce their categories, characteristics, and development. Methods: This article summarizes various scientific research achievements in the zero gravity test of solar wings, and introduces the advantages and disadvantages of the zero gravity test method of solar wings. Conclusion: Although research on zero-gravity unloading test systems for solar wings is continuously advancing, there are still several technological bottlenecks that need to be overcome in terms of system precision, payload capacity, dynamic simulation, method optimization, diversifying zero-gravity test methods and system universality for different types of solar panel unloading.

Experimental study on thermally induced vibration of flexible solar cell wing simulator

Abstract With the development of large spacecraft and satellite payloads, the power supply required is increasing, especially in space solar power stations, and the large flexible solar wing is an inevitable trend in the future. Due to their light weight and large area, flexible solar wings may face thermally induced vibration during orbit operation, which will lead to the degradation of spacecraft performance and even structural damage. In this paper, the test method of a flexible solar wing simulator is established, and the thermally induced vibration test of a flexible solar cell wing simulator is carried out. And vibration amplitude value is 25 and 9 microns with a frequency 0.56Hz.The characteristic of thermally induced vibration of flexible solar cell wing is given, which provides a basis for its thermally induced vibration suppression.

Significant statistical model of heat transfer rate in radiative Carreau tri-hybrid nanofluid with entropy analysis using response surface methodology used in solar aircraft

The recent advancement of technologies focuses on the use of solar-based heat radiation and nanotechnology. The primary source of heat is solar energy, which is obtained by absorbing sunlight. In addition, solar thermal planes, photovoltaic cells, and sun-based hybrid nanofluids all help to harness solar energy. Therefore, main concern of the study is to explored the two-dimensional Engine oil-based Carreau tri-hybrid nanofluid (SiO2 (silica dioxide), MOS2 (Molybdenum disulfide), Fe3O4(black iron oxide)) flow via a stretching sheet within solar wings. The flow phenomena of the non-Newtonian fluid enrich for the effects of radiant energy and the external heat source. By adopting similarity transfiguration, the dimensional partial main flow equations are changed into nonlinear dimensionless ordinary differential equations. The most effective and powerful tool of the semi-analytical method ADM (Adomain Decomposition Method) is utilized to solve the nanofluid flow problem. The uniqueness of the proposed study arises due to the analysis of entropy generation obtained by various irreversibility processes. The graphical illustration of outcome of various governing parameters on velocity, temperature, entropy terms and engineering quantities have been presented and theoretically analyzed. The findings reveal that The Carreau ternary hybrid nanofluids enhance the system's thermal conductivity for optimal temperature regulation in solar aircraft and better heat dissipation. The use of Carreau ternary hybrid nanofluids significantly reduces entropy generation, which implies a more reversible process, enhancing the overall efficiency of the energy conversion systems in solar aircraft. The heat flow of the system is accurately reflected by the chosen variables and their interactions, as demonstrated by the constructed model's strong statistical significance. For real-world applications, this improves the model's predictability and dependability.

Optimization Design of Redundant Parallel Posture Adjustment Mechanism for Solar Wing Docking Based on Response Surface Methodology

The parallel mechanism exhibits high stiffness and excellent dynamic response, making it ideal for high-precision applications. In our early work, a novel 6-DOF redundant parallel posture mechanism with four limbs for solar wing docking has been proposed; each limb consists of three links and four joints. This paper primarily focuses on optimization design of the mechanism. The calculation of workspace volume reveals that factors influencing the range of posture adjustment include dynamic platform parameters, static platform parameters, the drive trajectory of each kinematic pair, and the angles between each kinematic pair. A sensitivity analysis was conducted to examine the impact of each parameter on the range of posture adjustment. To reduce computational complexity and improve analysis efficiency, a combined approach of single-factor analysis and response surface methodology (RSM) is used in the paper. Single-factor analysis is utilized to evaluate the effect of each parameter on the posture adjustment range. Based on these results, RSM is used to establish a regression model for parameters; thereby, the optimal parameter combination for the mechanism is determined. The regression coefficient R2 = 0.9374 attests to the validity of the proposed model. Finally, a comparison of the posture adjustment range before and after optimization is presented, providing a foundation for the practical application of the redundant parallel mechanism. This paper introduces a novel structural design concept aimed at resolving the conflict between heavy loads and compact sizes in redundant parallel mechanisms while providing valuable insights for miniaturized design.

Sensitivity analysis of frequency response functions with imaginary parts decoupling based on multicomplex-step perturbation

Imaginary perturbation is used in the complex step differentiation method to compute first-order derivatives, widely known as an effective approach for sensitivity analysis in structural dynamics. However, coupling of imaginary parts occurs in the damped frequency response functions when employing this method. To mitigate this coupling, a novel approach for sensitivity analysis based on multicomplex-step perturbation is proposed in this paper, for sensitivity analysis of Frequency Response Functions in structural dynamics. The structural parameters are perturbed in multicomplex domain, the dimensions of structural matrices are expanded using the Cauchy Riemann matrix representation, the equation of motion for sensitivity analysis in frequency domain is transformed to matrix operation in field of real numbers, imaginary term will not exist in the equation of motion for sensitivity analysis, the imaginary part of the frequency response function and the imaginary part of the perturbation are decoupled, the structural frequency response functions and the corresponding sensitivities are obtained from the dimension-expanded equation of motion. A truss structure and a solar wing are adopted to verify the accuracy of the proposed method. Results show that the sensitivity of FRFs can be effectively calculated using the proposed method. Compare to the finite difference method, the proposed method is not depended on the step-size selection procedure. The multi-order and mixed-order sensitivity matrices, especially Hessian matrix can also be obtained using the proposed method.

Design and investigation of flexible solar wing: In-plane dynamics

Space satellites are increasingly using flexible solar wings. The dynamic behavior of the flexible solar array in orbit, which is related to the service life, has not been fully studied. In this paper, a new flexible hinge design is proposed for connecting multiple solar arrays, and its influence on the in-plane nonlinear dynamic characteristics of the array is investigated. The novelty of this research lies in the exploration of the deformation mechanisms of these hinges, where a nonlinear static model is developed based on Hamilton principle to accurately predict stiffness properties. Since the nonlinearity of the hinge stiffness has a significant effect on the system response, the combination of complex dynamic frequency (CDF) method and the arc length method are applied to obtain the analytic solution of in-plane dynamic model. During the ground testing, diverse patterns of response are finally discovered, and nonlinear behaviors such as snap-through occurred. These results reveal that by adjusting hinge parameters, both the hinge stiffness and the resonance frequency of the flexible solar wing can be effectively modified. This research provides critical insights and guidance for enhancing the design of structural static margins, avoiding interference frequency bands, and improving system stability.

Configuration design of movable heavy-duty reconfigurable posture adjustment platform with dual motion modes

AbstractThe existing single-mode posture adjustment equipment for solar wing docking is only suitable for a limited number of satellite dimensions; it could not meet the diverse development trends of satellite models. The working range requirements are different when different-sized satellites dock with the solar wing, and the docking process is divided into two stages in this paper. While the DOFs required for the two stages are different, a movable heavy-load reconfigurable redundant posture adjustment platform (RrPAP) with dual motion modes is proposed in this paper. The RrPAP consists of a wheeled mobile platform and a reconfigurable parallel posture adjustment mechanism (PAM). The micro-motion PAM limb types are synthesized, and the comprehensive load-bearing index is proposed to select the mechanism types for heavy-load conditions. A decentralized four-limb six-degree-of-freedom (6-DOF) parallel micro-motion PAM is designed. In the macro-motion stage, for the PAM to still have a defined motion after being released from ground constraints, a serial coupling sub-chain is designed between adjacent limbs to restrict relative movement between them. A type synthesis method for symmetrically coupled mechanisms based on mechanism decoupling and motion distribution is proposed. Four types of symmetrically coupled mechanisms with multi-loop consisting of serial coupling sub-chains are synthesized by using this method. The feasibility of the proposed method is demonstrated through an example using the constraint synthesis method based on screw theory. This work provides a foundation for subsequent refinement and expansion of type synthesis theories and the selection of new types of mechanisms.

Research on the Model Construction and Characteristics of Solar Radiation Received by Solar Wing Coupled with Compound Parabolic Concentrator

Research on the Model Construction and Characteristics of Solar Radiation Received by Solar Wing Coupled with Compound Parabolic Concentrator

Similitude laws for dynamic response of beam-plate coupled structure

The beam-plate coupled structure is a typical structure in spacecraft solar wings, and the prediction of its mechanical environment is crucial for overall design, structure and mechanism subsystem design. However, it is usually difficult to perform ground simulation tests on spacecraft solar wings with full-size structure. Therefore, a scaled model is established based on similarity theory to forecast the dynamic response of the full-size structure. In this article, finite element (FE) and hybrid finite element-statistical energy analysis (FE-SEA) models of the beam-plate coupled structure are established according to the band division principle. Finite element model allows for detailed analysis of structural behaviour, while hybrid models incorporate statistical energy analysis to account for high-frequency dynamics. By integrating these approaches, a comprehensive understanding of the coupled structure’s response can be achieved, facilitating efficient design and optimisation processes. The scaling laws of the dynamic response are obtained by combining the dimensional analysis and equation analysis methods, respectively. The scaled models are designed for verification, and the natural characteristics and vibration responses predicted by the scaled models are basically consistent with those of the prototype. The findings indicate that the prediction accuracy derived from the FE-SEA model is higher, which provides a novel approach for the dynamic similarity of complicated structures such as the solar wings of spacecraft.

Embedded piezoelectric actuation method for enhanced solar wings vibration control

The solar wing is a vital energy component of spacecraft. It often faces challenges from vibrations and deformations during orbit, impacting spacecraft pointing accuracy and operational performance. To address these issues, a novel actuation method based on embedded piezoelectric actuator (EPA) is proposed in this study, which overcomes the technical difficulties of large additional mass and volume, and low control effectiveness. Firstly, a sandwich stacked EPA is meticulously designed and embedded into the connecting rod based on comprehensive analysis. Secondly, a novel modeling using the transfer matrix method improves the computational accuracy and the evaluation efficiency. Finally, a prototype of the EPA is fabricated, and the measurement system is constructed. The correctness of the modeling and the feasibility of the design are verified by case studies. The applications of the EPA for active vibration control are verified by additional case studies of the connecting rod and the scaled solar wing prototype, respectively. The results reveal the amplitude reduction rates at the natural frequency are 97.36% and 97.48% in the XOZ plane and YOZ plane, respectively, with residual disturbances limited to only 0.03 mm. The exemplary outcomes solidify the exceptional performance of the proposed embedded piezoelectric actuation method for the active vibration control of solar wings. This novel method holds great promise for enhancing spacecraft stability and performance.

Hybrid Strategy Improved Beetle Antennae Search Algorithm and Application

The multi-dimensional optimization of mechanisms is a typical optimization problem encountered in mechanical design. Herein, the Hybrid strategy improved Beetle Antennae Search (HSBAS) algorithm is proposed to solve the multi-dimensional optimization problems encountered in structural design. To solve the problems of local optimization and low accuracy of the high-dimensional solution of the Beetle Antennae Search (BAS) algorithm, the algorithm adopts the adaptive step strategy, multi-directional exploration strategy, and Lens Opposition-Based Learning strategy, significantly reducing the probability of the algorithm falling into the local optimum and improving its global search capability. Comparative experiments of the improved algorithm are carried out by selecting eleven benchmark test functions. HSBAS can reach 1 × 10−22 accuracy from the optimal value when dealing with low-dimensional functions. It can also obtain 1 × 10−2 accuracy when dealing with high-dimensional functions, significantly improving the algorithm’s capability. According to Friedman’s ranking test result, HSBAS ranks first, which proves that HSBAS is superior to the other three algorithms. The HSBAS algorithm is further used to optimize the design of the altitude compensation module of the gravity compensation device for solar wings, controlling the fluctuation of bearing capacity within 0.25%, which shows that the algorithm can be used as an effective tool for engineering structural optimization problems.

Reliability assessment of man‐machine systems subject to probabilistic common cause errors

AbstractThe occurrence of probabilistic common cause errors (PCCEs) in man‐machine systems can lead to multiple human errors being affected by common causes and will contribute greatly to the reliability of the system. In this paper, A reliability modeling method based on event tree (ET)‐fault tree (FT) model for man‐machine systems subjected to PCCEs is proposed. Under the influence of PCCEs, risk factors in the system are not independent, and human errors affected by the same common cause will occur with different probabilities. To describe the dependencies among risk factors, a PCCE gate is proposed to extend FTs in the ET‐FT model. To analyze the impact of common causes on the human error probabilities and quantify the extended FT, an explicit method and an implicit method based on the Cognitive Reliability and Error Analysis Method are proposed. The proposed quantification methods consider the different relationships among multiple common causes in a single model. Finally, the proposed methods are validated in the reliability assessment of the emergency response system under malfunction of the solar wing mechanism.

Vibration Characteristics of Asymmetric Flexible Cantilever Beams Connected to a Central Rigid Body

A satellite with two solar wings can be modeled using a pair of symmetric flexible cantilever beams connected to a central rigid body. Due to certain reasons, the symmetric flexible cantilever beams may be turned into asymmetric ones, which will inevitably influence the vibration properties of the structural system. By changing the structural sizes and adding local mass on one side of the two beams, a structural system with asymmetric mass distribution is obtained and its vibration characteristics are investigated. Hamilton’s principle with the assumed mode method is employed to establish the equation of motion of the asymmetric structural system. The natural frequencies, mode shapes, frequency response curves and displacement time histories of the system are calculated, and they are compared with those of the structural system with a symmetric mass distribution. The correctness and feasibility of the present analytical method are verified by means of the finite element method (FEM) and a vibration experiment. The analytical results show that the mass asymmetry of the two beams leads to the mode localization phenomenon, and the coupling effect between the two beams and the central rigid body is enhanced. The larger the mass asymmetry is and the closer the position of the added local mass to the end of the cantilever beam is, the more obvious of the mode localization phenomenon is and the more obvious of the coupling effect between the two beams and the central rigid body is. The present investigation results are helpful for the dynamic analysis and design of spacecraft structures composed of flexible solar wings and a central rigid body.

Characteristics of Solar Radiation Reception by Solar Wing Based on Congruent Concentrating Surface

Characteristics of Solar Radiation Reception by Solar Wing Based on Congruent Concentrating Surface

Model construction and performance investigation of compound parabolic concentrator based on satellite solar wing photovoltaic arrays

Experimental research has shown that applying solar concentrator to satellite system could significantly improve its comprehensive benefits. Therefore, theoretical, experimental and numerical studies on satellite solar wing coupled with CPC (Compound Parabolic Concentrator, CPC) are carried out in this study. A mathematical model of SSW-CPC (Satellite Solar Wing CPC, SSW-CPC) which is suitable for space Satellite Solar Wing is theoretically constructed, and the concentrating performance of the constructed SSW-CPC is verified by the visual laser experiment. The results show that the concentrating performance of SSW-CPC is consistent with the theoretical results, and the energy flux distribution on the absorber surface has better uniformity. The study of synchronous satellites operation at the equatorial plane also found that the power generation of the SSW-CPC has increased by 24.4 % compared to the conventional satellite solar wing, which can provide more rapid, abundant and stable power resources for the electrical equipment of satellite system. The results of the economic evaluation show that the mass of satellite system is reduced by 5.3 %, which is beneficial to save the launch cost.

Study on the measurement method of polyimide electrical properties for flexible solar wing

AbstractFlexible solar wings with high energy density, lightweight, small size and large deployment area are one of the first choices for next‐generation spacecraft. However, the flexible solar wings are subjected to irradiation in space and tensile mechanical stress, which produce the charge accumulation effect and result in electrostatic discharge. It is necessary to establish a test method for the conductivity and space charge behaviour of polyimide under tensile stress. The stress–strain characteristics of polyimide under different tensile stresses are studied by the authors. The longitudinal length‐strain characteristics and transverse thickness evolution characteristics under different stresses are also obtained. The results show that the variation of film thickness with tensile force is only about 1% before the yield point. The polyimide films from 50 to 200 μm thick have similar yield and tensile strengths. The ultimate stress of the specimen decreases from approximately 126 to 103 MPa with increasing thickness. The thickness model of polyimide under tensile stress were obtained, which could accurately calculate the voltage amplitude applied on the specimens for measuring the conductivity under different tensile stresses. A basis for investigating the stress–strain characteristics of polyimide films under different tensile stresses are provided, which will facilitate the formulation selection and performance improvement of polyimide for flexible solar wings of spacecraft.

Improvement of mechanical energy using thermal efficiency of hybrid nanofluid on solar aircraft wings: an application of renewable, sustainable energy

ABSTRACT The modern world uses sun-based thermal radiation and nanotechnology to promote new technologies. In addition to solar thermal aircraft, photovoltaic cells, and sun-based hybrid nanofluids, solar energy is the primary source of heat derived from the absorption of sunlight. Researchers are currently investigating the application of nanotechnology to sun-based thermal radiation with the intent of enhancing the efficiency of aircraft flight. This study is focused on the research of heat transport via employing hybrid nanofluid on the interior of solar wings using a parabolic trough solar collector (PTSC) to enrich the investigations of the solar aircraft wing. In addition, the thermodynamics of entropy production for steady tangent hyperbolic fluid is examined for its energy balance and usefulness for significant physical influenced parameters. This study examines the viscoelastic properties of the thermal transfer process of two distinct kinds of nano solid particles, zirconium dioxide and copper (Cu), with non-Newtonian EG (ethylene glycol) as the base fluid. To achieve the model's aims, a novel solution, namely wavelets and the Chebyshev wavelets method (CWM), was employed to solve the velocity, energy equation, and entropy generation. .

Research on Automatic attitude adjustment Technology of Suspension rail of the Unfolding frame

Spacecraft solar wings, antennas, and other space deployment mechanisms need to be unloaded by gravity during the ground launch test. At present, the most widely used is the guide rail type Micro-gravity unfolding frame, and the rail needs to be adjusted horizontally before the test is carried out. Aiming at the shortcomings of the current rail debugging relying on labor, difficult high-altitude operation, and low debugging efficiency, a guide rail automatic attitude adjustment device is proposed, which can quickly realize the efficient adjustment and attitude maintenance of the rail level. After test verification, the system can increase the local level of the guide rail from the traditional 0.02 mm/m to 0.01 mm/m, the overall level from the original 0.1 mm/m to 0.02 mm/m, and shorten the commissioning time from the original 4 h to 1 h. The power-off holding ability is strong, which greatly improves the efficiency of the ground test. The research results have been applied to other spatial deployment institutions that conduct tests based on rails.

Bending test and simulation of carbon fiber aluminum honeycomb sandwich structure

According to the bending moment characteristics of carbon fiber aluminum honeycomb sandwich structure for the solar wing in use, this paper simulates and analyzes the large-scale bending samples and tests the bending samples at room temperature, 150 °C, and -150°C. The test results show that the bending performance is not different between low-temperature environment and room temperature environment, but the stiffness and strength at high temperature are reduced by 54.9% and 50%, respectively, compared with room temperature. Compared with the room temperature test results, the simulation results are about 10%, which can roughly reflect the bending performance characteristics of sandwich structures.

Autonomous Wheel Off-Loading Strategies for Deep-Space CubeSats

Deep-space CubeSats missions require careful trade-offs on design drivers such as mass, volume, and cost, while ensuring autonomous operations. This work elaborates the possibility of off-loading the reaction wheels without the need of carrying a bulky and expensive reaction control system or the field-dependent magnetotorquers. The momentum accumulated along two body axes can be removed by either offsetting the main thruster with a gimbal mechanism or by tilting differentially the solar wings. The dumping on the third axis can be still accomplished by imposing a specific attitude trajectory with the motion of either the gimbal or the arrays drive mechanism. The M-Argo CubeSat is selected as case study to test the techniques along its deep-space trajectory. The strategies decision-making is autonomously carried out by a state machine. The off-loading during the cruising arcs employs the gimballed thruster and takes typically 3 h, granting a mass savings of more than 99% with respect to the usage of a reaction control system. The trajectory is shown to have negligible differences with respect to the nominal one, since the thrust is corrected accordingly. During the coasting arcs, the solar arrays are tilted and several hours are required, depending on the Sun direction and intensity, but the propellant is completely saved. Sensitivity analyses are also carried out on the initial angular momentum components and the center of mass displacement to check the robustness of the algorithms.