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Hexi Baoyin - One of the best experts on this subject based on the ideXlab platform.
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coupled attitude orbit dynamics and control for displaced Solar Orbits
Acta Astronautica, 2009Co-Authors: Shengping Gong, Hexi BaoyinAbstract:Abstract The paper discusses the coupled attitude–orbit dynamics of a Solar sail. The equilibrium point of the coupled dynamical equations is obtained by designing the inertia of the sail. The stability of the equilibrium is analyzed through a linearization. It is found that the stability of the coupled equilibrium is determined by the stability of the attitude and orbital equilibrium point, respectively. For the sail discussed in this paper, the stability of the orbital equilibrium determines the stability of coupled system since the attitude is always marginally stable. Several numerical examples are employed to validate the conclusions. For unstable displaced Orbits, active control is employed to stabilize the attitude and orbit. The results show that a small control torque can stabilize both the attitude and orbit.
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analysis of displaced Solar sail Orbits with passive control
Journal of Guidance Control and Dynamics, 2008Co-Authors: Shengping Gong, Hexi BaoyinAbstract:T HEuse of Solar radiation pressure wasfirst proposed by a Soviet pioneer of astronautics, Tsiolkovski, and the technology was greatly developed by NASA for a proposed comet Halley rendezvous mission in the 1970s [1,2]. Recently, many space applications of Solar sails are proposed because Solar sails enable some special missions which would be impossible for any conventional space propulsion. Such missions include displaced Solar Orbits, geocentric halo Orbits, Mercury sun-synchronous polar orbit, artificial Lagrange points, and so on. Leipold and Wagner investigated the Mercury sun-synchronous polar orbit using Solar sail propulsion to explore the inner Solar system [3]. West investigated the new artificial Lagrange points created by Solar sails to provide early warning of Solar plasma storms before they reach the Earth [4]. McInnes and Simmons have done much work on the dynamics and control of Solar sails on different exotic trajectories [5,6]. The stability of Solar sails on displaced Solar Orbitswith passive control is investigated in [7], and the results show that the sails are stable if the sail pitch angle is fixed with respect to a rotating frame. The passive stability can be realized by designing the configuration of the sail, which is investigated in [8]. Passive control is a good option for the Solar sail because its large and complex structure may introduce some difficulties for active control. In this Note, the global stability of the Solar sail with passive control is investigated by considering the dynamics in an inertial frame. It is found that the sail is stable with any initial values, and the sail will oscillate in the vicinity of a nominal orbit that is uniquely determined by the angular momentum of the sail. The amplitudes of the oscillations are determined by the initial values of the radius and angular velocity.
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relative orbit design and control of formation around displaced Solar Orbits
Aerospace Science and Technology, 2008Co-Authors: Shengping Gong, Hexi BaoyinAbstract:This paper investigates the relative orbit design and control methods for formation flying around displaced Solar Orbits. Firstly, the relative equations of motion are developed and linearized. Then, two types of orbit design and control methods are discussed based on the linearized equations. One method uses only position feedback to control the formation, in which the relative orbit can be controlled to be an ellipse. Further, the period of relative motion and direction of relative motion plane can be designed as mission requirements. The advantage of the method is that it employs an approximate system instead of a true one to design the parameters, which overcomes the trouble of solving a transcendental equation. The other method uses the full state feedback to control the formation, in which the relative orbit can be designed arbitrarily. Two control strategies, Linear Quadratic Regulation (LQR) and Input Feedback Linearization (IFL), are discussed for the latter. Finally, simulations are given to validate the two methods.
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Solar sail formation flying around displaced Solar Orbits
Journal of Guidance Control and Dynamics, 2007Co-Authors: Shengping Gong, Hexi BaoyinAbstract:R ECENTLY, attention has been focused on Solar sail missions, such as the new artificial Lagrange points created by Solar sails to be used to provide early warning of Solar plasma storms, before they reach Earth [1,2]. There are several prior references with regard to such Orbits in the literature. As early as 1929, Oberth mentioned in his study that Solar radiation pressure would displace a reflector in an Earth polar orbit in the anti-sun direction, so that the orbit plane did not contain the center-of-mass of the Earth [3]. Later, in 1977, Austin et al. [4] noted that propulsive thrust can be used to displace the orbit of an artificial body, but only small displacements were considered for spacecraft proximity operations, and no analysis of the problem was provided. Similarly, Nock suggested a displaced orbit above Saturn’s rings for in situ observation, however, again no analysis was given [3]. In 1981, Forward [5] considered a displaced Solar sail north or south of the geostationary ring. However, because he did not use an active control, subsequent analysis has criticized thiswork and claimed that such Orbits were impossible. More recently, McInnes and Simmons have done work in which large families of displaced Orbits were found by considering the dynamics of a Solar sail in a rotating frame [6], and the dynamics, stability, and control of different families of displaced Orbits were investigated in detail [7,8]. Based on McInnes’ and Simmons’ work [6], Molostov and Shvartsburg considered a more realistic Solar sail model with nonperfect reflectivity and discussed the effect of finite absorption of the sail on the displaced Orbits [9,10]. However, studies of the relative motion of Solar sails are rare in the literature. The original idea of formation flying around a displaced orbit considered in this note comes from the concept of combining a displaced orbit with formation flying to achieve greater resolution than a single sail for science missions. This note outlines the characteristics of the relative motion around a displaced Solar orbit and proposes some possible control strategies. Because the relative distance between the sails is very small compared with the distance from the sun to the sails, the relative equation of motion is linearized in the vicinity of a displaced Solar orbit. Based on the linearized equation, two types of formations, seminatural and controlled formations, are discussed. The seminatural formations are performed with only sail attitude variations, but configurations of the relative Orbits strongly depend on the orbit of the leader sail. Therefore, more complex controllers are adopted to build more sophisticated formations to meet special demands on the relative orbit configurations.
Shengping Gong - One of the best experts on this subject based on the ideXlab platform.
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spin stabilized Solar sail for displaced Solar Orbits
Aerospace Science and Technology, 2014Co-Authors: Shengping GongAbstract:Abstract An optical force model is used to investigate the stability of a flat spinning Solar sail in a displaced Solar orbit. The Solar sail can be stabilized in the orbit by design of the spinning rate and the sail structure. The orbital and attitude dynamics are studied separately. The orbit is stable as the sail attitude keeps fixed with respect to the sunlight, as does that of a perfectly reflecting Solar sail. The attitude is stable as long as the spin angular velocity is much larger than the orbital angular velocity. The stability of the individual components cannot guarantee the stability of the entire system since the orbit and attitude interact with each other. Therefore, the coupled dynamics of the orbit and attitude are used to study the overall stability; the results show that the coupled system is also stable. It should be noted that the orbit and attitude are critically not asymptotically stable. The analysis only provides the necessary conditions for stability because a linearization is performed. To numerically verify the nonlinear stability of the true nonlinear system, the dynamical equations are simulated for a time that is longer than the mission life.
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coupled attitude orbit dynamics and control for displaced Solar Orbits
Acta Astronautica, 2009Co-Authors: Shengping Gong, Hexi BaoyinAbstract:Abstract The paper discusses the coupled attitude–orbit dynamics of a Solar sail. The equilibrium point of the coupled dynamical equations is obtained by designing the inertia of the sail. The stability of the equilibrium is analyzed through a linearization. It is found that the stability of the coupled equilibrium is determined by the stability of the attitude and orbital equilibrium point, respectively. For the sail discussed in this paper, the stability of the orbital equilibrium determines the stability of coupled system since the attitude is always marginally stable. Several numerical examples are employed to validate the conclusions. For unstable displaced Orbits, active control is employed to stabilize the attitude and orbit. The results show that a small control torque can stabilize both the attitude and orbit.
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analysis of displaced Solar sail Orbits with passive control
Journal of Guidance Control and Dynamics, 2008Co-Authors: Shengping Gong, Hexi BaoyinAbstract:T HEuse of Solar radiation pressure wasfirst proposed by a Soviet pioneer of astronautics, Tsiolkovski, and the technology was greatly developed by NASA for a proposed comet Halley rendezvous mission in the 1970s [1,2]. Recently, many space applications of Solar sails are proposed because Solar sails enable some special missions which would be impossible for any conventional space propulsion. Such missions include displaced Solar Orbits, geocentric halo Orbits, Mercury sun-synchronous polar orbit, artificial Lagrange points, and so on. Leipold and Wagner investigated the Mercury sun-synchronous polar orbit using Solar sail propulsion to explore the inner Solar system [3]. West investigated the new artificial Lagrange points created by Solar sails to provide early warning of Solar plasma storms before they reach the Earth [4]. McInnes and Simmons have done much work on the dynamics and control of Solar sails on different exotic trajectories [5,6]. The stability of Solar sails on displaced Solar Orbitswith passive control is investigated in [7], and the results show that the sails are stable if the sail pitch angle is fixed with respect to a rotating frame. The passive stability can be realized by designing the configuration of the sail, which is investigated in [8]. Passive control is a good option for the Solar sail because its large and complex structure may introduce some difficulties for active control. In this Note, the global stability of the Solar sail with passive control is investigated by considering the dynamics in an inertial frame. It is found that the sail is stable with any initial values, and the sail will oscillate in the vicinity of a nominal orbit that is uniquely determined by the angular momentum of the sail. The amplitudes of the oscillations are determined by the initial values of the radius and angular velocity.
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relative orbit design and control of formation around displaced Solar Orbits
Aerospace Science and Technology, 2008Co-Authors: Shengping Gong, Hexi BaoyinAbstract:This paper investigates the relative orbit design and control methods for formation flying around displaced Solar Orbits. Firstly, the relative equations of motion are developed and linearized. Then, two types of orbit design and control methods are discussed based on the linearized equations. One method uses only position feedback to control the formation, in which the relative orbit can be controlled to be an ellipse. Further, the period of relative motion and direction of relative motion plane can be designed as mission requirements. The advantage of the method is that it employs an approximate system instead of a true one to design the parameters, which overcomes the trouble of solving a transcendental equation. The other method uses the full state feedback to control the formation, in which the relative orbit can be designed arbitrarily. Two control strategies, Linear Quadratic Regulation (LQR) and Input Feedback Linearization (IFL), are discussed for the latter. Finally, simulations are given to validate the two methods.
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Solar sail formation flying around displaced Solar Orbits
Journal of Guidance Control and Dynamics, 2007Co-Authors: Shengping Gong, Hexi BaoyinAbstract:R ECENTLY, attention has been focused on Solar sail missions, such as the new artificial Lagrange points created by Solar sails to be used to provide early warning of Solar plasma storms, before they reach Earth [1,2]. There are several prior references with regard to such Orbits in the literature. As early as 1929, Oberth mentioned in his study that Solar radiation pressure would displace a reflector in an Earth polar orbit in the anti-sun direction, so that the orbit plane did not contain the center-of-mass of the Earth [3]. Later, in 1977, Austin et al. [4] noted that propulsive thrust can be used to displace the orbit of an artificial body, but only small displacements were considered for spacecraft proximity operations, and no analysis of the problem was provided. Similarly, Nock suggested a displaced orbit above Saturn’s rings for in situ observation, however, again no analysis was given [3]. In 1981, Forward [5] considered a displaced Solar sail north or south of the geostationary ring. However, because he did not use an active control, subsequent analysis has criticized thiswork and claimed that such Orbits were impossible. More recently, McInnes and Simmons have done work in which large families of displaced Orbits were found by considering the dynamics of a Solar sail in a rotating frame [6], and the dynamics, stability, and control of different families of displaced Orbits were investigated in detail [7,8]. Based on McInnes’ and Simmons’ work [6], Molostov and Shvartsburg considered a more realistic Solar sail model with nonperfect reflectivity and discussed the effect of finite absorption of the sail on the displaced Orbits [9,10]. However, studies of the relative motion of Solar sails are rare in the literature. The original idea of formation flying around a displaced orbit considered in this note comes from the concept of combining a displaced orbit with formation flying to achieve greater resolution than a single sail for science missions. This note outlines the characteristics of the relative motion around a displaced Solar orbit and proposes some possible control strategies. Because the relative distance between the sails is very small compared with the distance from the sun to the sails, the relative equation of motion is linearized in the vicinity of a displaced Solar orbit. Based on the linearized equation, two types of formations, seminatural and controlled formations, are discussed. The seminatural formations are performed with only sail attitude variations, but configurations of the relative Orbits strongly depend on the orbit of the leader sail. Therefore, more complex controllers are adopted to build more sophisticated formations to meet special demands on the relative orbit configurations.
X X Zhang - One of the best experts on this subject based on the ideXlab platform.
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interplanetary coronal mass ejections observed by ulysses through its three Solar Orbits
Solar Physics, 2010Co-Authors: Pingbing Zuo, X X ZhangAbstract:An extended Ulysses interplanetary coronal mass ejections (ICMEs) list is used to statistically study the occurrence rate of ICMEs, the interaction of ICMEs with Solar wind, and the magnetic field properties in ICMEs. About 43% of the ICMEs are identified as magnetic clouds (MCs). It is found that the occurrence rate of ICMEs approximately follows the Solar activity level, except for the second Solar orbit; the rate is higher in the southern heliolatitude than in the northern heliolatitude; and it roughly decreases with the increase of ICME speeds. Our results show that the speed difference between the ICME and the Solar wind in front of it shows a slight decrease with increasing heliocentric distance for ICMEs preceded by a shock, whereas no such dependence is found for the ICMEs without shock association. It is also found that approximately 23% of the ICMEs are associated with radial field events, in which the interplanetary magnetic field with near-radial direction lasts for many hours, in the Ulysses detected range, and these associated events are not necessarily confined to fast ICMEs or the trailing portions of ICMEs. Nearly all these associated events occur during the period of declining Solar wind speed and most of them occur at low heliolatitudes.
Yanfang Liu - One of the best experts on this subject based on the ideXlab platform.
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the coupled orbit attitude dynamics and control of electric sail in displaced Solar Orbits
International Journal of Aerospace Engineering, 2017Co-Authors: Mingying Huo, He Liao, Yanfang LiuAbstract:Displaced Solar Orbits for spacecraft propelled by electric sails are investigated. Since the propulsive thrust is induced by the sail attitude, the orbital and attitude dynamics of electric-sail-based spacecraft are coupled and required to be investigated together. However, the coupled dynamics and control of electric sails have not been discussed in most published literatures. In this paper, the equilibrium point of the coupled dynamical system in displaced orbit is obtained, and its stability is analyzed through a linearization. The results of stability analysis show that only some of the Orbits are marginally stable. For unstable displaced Orbits, linear quadratic regulator is employed to control the coupled attitude-orbit system. Numerical simulations show that the proposed strategy can control the coupled system and a small torque can stabilize both the attitude and orbit. In order to generate the control force and torque, the voltage distribution problem is studied in an optimal framework. The numerical results show that the control force and torque of electric sail can be realized by adjusting the voltage distribution of charged tethers.
Pingbing Zuo - One of the best experts on this subject based on the ideXlab platform.
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interplanetary coronal mass ejections observed by ulysses through its three Solar Orbits
Solar Physics, 2010Co-Authors: Pingbing Zuo, X X ZhangAbstract:An extended Ulysses interplanetary coronal mass ejections (ICMEs) list is used to statistically study the occurrence rate of ICMEs, the interaction of ICMEs with Solar wind, and the magnetic field properties in ICMEs. About 43% of the ICMEs are identified as magnetic clouds (MCs). It is found that the occurrence rate of ICMEs approximately follows the Solar activity level, except for the second Solar orbit; the rate is higher in the southern heliolatitude than in the northern heliolatitude; and it roughly decreases with the increase of ICME speeds. Our results show that the speed difference between the ICME and the Solar wind in front of it shows a slight decrease with increasing heliocentric distance for ICMEs preceded by a shock, whereas no such dependence is found for the ICMEs without shock association. It is also found that approximately 23% of the ICMEs are associated with radial field events, in which the interplanetary magnetic field with near-radial direction lasts for many hours, in the Ulysses detected range, and these associated events are not necessarily confined to fast ICMEs or the trailing portions of ICMEs. Nearly all these associated events occur during the period of declining Solar wind speed and most of them occur at low heliolatitudes.