Moving-mass-based station keeping of stratospheric airships

2021 ◽  
pp. 1-14
Author(s):  
L. Chen ◽  
Q. Gao ◽  
Y. Deng ◽  
J. Liu
Keyword(s):  
Attitude Control ◽  
Moving Mass ◽  
Solar Panels ◽  
Nonlinear Feedback ◽  
Station Keeping ◽  
Output Performance ◽  
Moving Mass Control ◽  
Vectored Thrust ◽  
Long Endurance ◽  
Aerodynamic Surfaces

Abstract Stratospheric airships are lighter-than-air vehicles that work at an altitude of 20km in the lower calm portion of the stratosphere. They can be used as real-time surveillance platforms for environment monitoring and civil communication. Solar energy is the ideal power choice for long-endurance stratospheric airships. Attitude control is important for airships so that they can point at a target for observation or adjust the attitude to improve the output performance of solar panels. Stratospheric airships have a large volume and semi-flexible structure. The typical actuators used are aerodynamic surfaces, vectored thrust and ballonets. However, not all these actuators can work well under special working conditions, such as low density and low speed. In this study, moving-mass control is introduced to stratospheric airships because its control efficiency is independent of airspeed and atmospheric density. A nonlinear feedback controller based on generalised inverse with a nonlinear mapping module is designed to implement moving-mass control. Such a new station keeping scheme with moving masses is proposed for airships with different working situations.

Multi-Scenarios Attitude Control of a Satellite with Flexible Solar Panels

2018 ◽  
Vol 11 (6) ◽  
pp. 326
Author(s):  
Nassima Khorchef ◽  
Abdellah Mokhtari ◽  
Abdelmadjid Boudjemai
Keyword(s):  
Attitude Control ◽  
Solar Panels

Boundary control design based on partial differential equation observer for vibration suppression and attitude control of flexible satellites with multi-section solar panels

2021 ◽  
pp. 107754632199015
Author(s):  
Mohammad Mahdi Ataei ◽  
Hassan Salarieh ◽  
Hossein Nejat Pishkenari ◽  
Hadi Jalili
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Attitude Control ◽  
Vibration Suppression ◽  
Equation System ◽  
Solar Panels ◽  
Attitude Dynamics ◽  
Partial Differential ◽  
Satellite Attitude ◽  
Element Technique

A novel partial differential equation observer is proposed to be used in boundary attitude and vibration control of flexible satellites. Solar panels’ vibrations and attitude dynamics form a coupled partial differential equation–ordinary differential equation system which is controlled directly without discretization. Few feedback signals from boundaries are required which are estimated via a partial differential equation observer. Consequently, just satellite attitude and angular velocity should be measured and still the control system benefits information from continuous part vibrations. The closed-loop system is proved to be asymptotically stable. Simulations with a finite element technique illustrate good performance of this observer-based boundary controller.

scholarly journals Experimental Investigation on the Feasibility of Using a Fresnel Lens as a Solar-Energy Collection System for Enhancing On-Orbit Power Generation Performance

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Tae-Yong Park ◽  
Joo-Yong Jung ◽  
Hyun-Ung Oh
Keyword(s):  
Power Generation ◽  
Solar Energy ◽  
Attitude Control ◽  
Incidence Angle ◽  
Fresnel Lens ◽  
Power Measurement ◽  
The Sun ◽  
Solar Panels ◽  
Collection System ◽  
Power Generation Performance

Cube satellites have a limitation for generating power because of their cubic structure and extremely small size. In addition, the incidence angle between the sun and the solar panels continuously varies owing to the revolution and rotation of the satellite according to the attitude control strategy. This angle is an important parameter for determining the power generation performance of the cube satellite. In this study, we performed an experimental feasibility study that uses a Fresnel lens as a solar-energy collection system for cube satellite applications, so that the power generation efficiency can be enhanced under the worst incidence angle condition between the sun and solar panels by concentrating and redirecting solar energy onto the solar panels with a commercial Fresnel lens. To verify the effectiveness of the proposed system, we conducted a power-measurement test using a solar simulator and Fresnel lenses at various angles to the light source. In addition, we predicted the on-orbit power-generation enhancement achieved by employing the solar-energy collection system with various attitude control strategies.

An IPEM for optimal control of uncertain beam-moving mass systems with saturation nonlinearity

2017 ◽  
Vol 24 (13) ◽  
pp. 2760-2781
Author(s):  
Xiao-Xiao Liu ◽  
Xing-Min Ren
Keyword(s):  
Nonlinear Control ◽  
Vibration Suppression ◽  
Estimation Method ◽  
Feedback System ◽  
Random Excitation ◽  
Point Estimation ◽  
Maximum Principles ◽  
Moving Mass ◽  
Nonlinear Feedback ◽  
Point Estimation Method

This paper addresses the vibration control of single-span beams subjected to a moving mass by coupling the saturated nonlinear control and an improved point estimation method (IPEM). An optimal nonlinear feedback control law, for a kind of uncertain linear system with actuator nonlinearities, is derived using the combination of Pontryagin's maximum principles and the improved point estimation method. The stability of the feedback system is guaranteed using a Lyapunov function. In order to obtain the instantaneously probabilistic information of output responses, a novel moment approach is presented by combining the improved point estimation method, the maximum entropy methodology and the probability density evolution theory. In addition to the consideration of stochastic system parameters, the external loadings are considered as a nonstationary random excitation and a moving sprung mass, respectively. The proposed strategy is then used to perform vibration suppression analysis and parametric sensitivity analysis of the given beam. From numerical simulation results, it is deduced that the improved point estimation method is a priority approach to the optimal saturated nonlinear control of stochastic beam systems. This observation has widespread applications and prospects in vehicle–bridge interaction and missile–gun systems.

Monitoring of a controlled space flexible multibody by means of embedded piezoelectric sensors and cameras synergy

2018 ◽  
Vol 29 (14) ◽  
pp. 2966-2978 ◽  
Author(s):  
Matteo Ribet ◽  
Marco Sabatini ◽  
Luca Lampani ◽  
Paolo Gasbarri
Keyword(s):  
Optical Sensors ◽  
Attitude Control ◽  
Point Of View ◽  
Vibration Monitoring ◽  
Structural Vibration ◽  
Elastic Displacement ◽  
Experimental Point ◽  
Solar Panels ◽  
Flexible Multibody ◽  
Usual Solution

Interaction between elastic dynamics and attitude control is a serious problem in space operations, which often involve satellites with highly flexible appendages. Monitoring and eventually control of the vibrations are a major concern to avoid a decrease in the expected performance. In particular, the classic case of a central bus with two lateral appendages (solar panels) is considered. The design of a system for structural vibration monitoring is proposed both from a numerical and an experimental point of view. Piezoelectric devices are a usual solution for measuring the deformation of the structures. In the proposed work, optical sensors are also implemented: the combined use of the two sets allows for the monitoring of the elastic displacement of the solar panels and for the reconstruction of the modal shapes of the entire flexible multibody system.

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