Attitude Stability Of Satellite Research Articles

Motion control of the satellite mounted robot arm which assures satellite attitude stability

When a robot arm is mounted on a satellite to perform some tasks, the satellite’s attitude must be stabilized to retain the communication link and to generate electrical power from solar panels. It is not realistic to control the total system as one dynamic system, since the number of degrees of freedom becomes too large to be handled by state-of-the-art satellite mounted computers. This paper proposes a coordinated control between the satellite’s attitude control system and the robot-arm control system. The robot-arm control system estimates the angular momentum of the planned robot-arm’s motion. The satellite’s attitude control system will compensate for the reaction by using feed-forward control. The robot-arm controller also manages the motion plan of the robot arm in order not to disturb the satellite’s attitude stability.

衛星塔載ロボットアームと衛星姿勢の協調制御 ロボットアーム動作時の衛星の姿勢安定の保証

When a robot arm is mounted on a satellite to perform tasks, the satellite attitude must be maintained to retain the communication link and to generate electrical power from its solar pannels. It is not realistic to control the total system as one dynamic system, since the number of degrees of freedom becomes large, and the computational requirement for the satellite-mounted computer becomes stringent. The proposed control method used independent control systems for control of the motion of the robot arm and satellite attitude control. The robot arm control system estimates the angular momentum which will be produced by the robot arm motion, and the attitude control system compensates for the disturbance by using the feedforward control. The robot controller also manages the motion plan of the robot arm in order not to disturb the satellite's attitude stability.

Coordinated control of spacecraft attitude and space manipulators

When a robot arm is mounted on a satellite to perform some tasks, the satellite's attitude must be stabilized to retain the communication link and to generate electrical power from solar panels. It is not realistic to control the total system as one dynamic system, since the number of degrees of freedom becomes too large to be handled by state-of-the-art satellite-mounted computers. This paper proposes a coordinated control between the satellite's attitude control system and the robot arm control system. The robot arm control system estimates the angular momentum of the planned robot arm's motion. The satellite's attitude control system will compensate for the reaction by using feed-foward control. The robot arm controller also manages the motion plan of the robot arm in order not to disturb the satellite's attitude stability.

Coordinated Control of Spacecraft's Attitude and its Manipulator. 3rd Report. Control of Satellite-Mounted Manipulator which Does Not Disturb Satellite Attitude Stability.

Manipulator motion on a satellite disturbes the stability of the satellite attitude. Since the reaction of a robot arm is too large to be compensated by the satellite attitude control system, it is necessary to control the satellite-mounted manipulator so that it does not to generate excess reaction torque against the satellite. In this paper, a simple and effective manipulator motion management algorithm is proposed. The manipulator motion is determined by considering the satellite attitude, attitude rate and the angular momentum which the manipulator will produce.

Satellite attitude stabilization through tether

Effective utilization of gravity gradient moments for attitude control demands rather slender satellite shapes. This imposes a major system design constraint and, further, provides only limited attitude accuracies, especially in the presence of disturbances and/or excitation. A new attitude control approach is presented here that overcomes most of these limitations. The proposed system configuration assumes a downward deployment of a ‘pendulum-like’ small mass from the satellite through a pair of identical tethers attached to its two distinct but symmetrically off-set points around the mass center. The well-known Lagrangian approach is utilized to obtain the governing equations of motion for the system in a circular orbit. A detailed stability analysis of motion-in-the-small is undertaken that establishes the feasibility of the concept. Furthermore, it leads to useful design criteria in the form of inequality constraints on the control parameters.

Fuzzy control for a non-linear MIMO plant subject to control constraints

A rule based fuzzy controller is presented for attitude stabilization of a small satellite in low earth orbit. Active control Is done by using 3-axis magneto-torquing. A preferred torque vector can not always be generated from the magnetic coils in certain regions of the orbit, due to an unfavourable direction of the geomagnetic field vector. The main objective of an acceptable control algorithm will then be to optimize the control effort: minimize the desired influence on the controlled axis and minimize the undesired disturbances to the other axes. It was found that a fuzzy controller can achieve these goals in a computationally effective way, compared to other more involved MIMO algorithms, while performing just as well or better under similar conditions. This fuzzy controller solves the control constraint problem by choosing the best magneto-torquer, the polarity and switching instances.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Attitude Stabilization and Control of the Brazilian Data Collecting Satellites

The Data Collecting Satellites (SCD) were developed and integrated at INPE, Brazil, with an aim of retransmiting meteorological data collected by automatic platforms spread over the country, The specified orbit for SCD1 and SCD2 are circular at 750 km altitude, with 25° inclination. SCD1 was launched in February 1993 by the Pegasus launcher (OSC). Both are spin stabilized, with magnetic attitude control coils. The angular velocity of the SCD2 spacecraft will be controlled by a spin plane magnetic coil, commanded by an onboard magnetometer.

Large angle pitch attitude maneuver of a satellite using solar radiation pressure

The force exerted by the solar radiation, though very small in magnitude, produces significant effects, especially in the case of high altitude satellites. The solar radiation pressure represents one freely available environmental force that may be put to use for various purposes. This may lead to enhancement of the life of the satellite since it consumes a very nominal amount of on-board energy. The advantages offered by the solar radiation pressure have drawn the attention of several researchers. Various controllers were proposed for many space missions, particularly for attitude control and stabilization of satellites. A controller for achieving large angle pitch attitude maneuver is described. The proposed control law is very simple in its form and requires a minimum number of on-board computations. Varieties of cases are tried and the effect of various parameters is studied. >

Attitude stability of a tethered satellite in locked rotation

The linear stability of the attitude of a tethered satellite system, consisting of an asymmetric satellite with two equal tethered masses arranged vertically, is studied. The differential equations of motion are established, the attitude stability conditions are found, and then entered into a Magnus triangle. It is concluded that a tether parameterΔ has a significant effect on the satellite's attitude stability. By increasing the value of Δ, the stable regions in the Magnus triangle grow, until they cover more than half of its area, and then decline to exactly one half.

Attitude stability of rigid satellites via a normalized Hamiltonian

A breakthrough is made in the long outstanding problem of attitude stability of a rigid satellite in a circular orbit. The focus is on an equilibrium at which the linearized techniques are inconclusive and no Liapunov function is known. In this paper, the Hamiltonian for the attitude motion of the satellite is expanded about the equilibrium up to the terms of degree four. By a sequence of canonical transformations, the expansion is brought to a normal form. A region in the parameter space for which the equilibrium orientation is stable is demarcated by an application of a recent extension of KAM theory to the normal form of Hamiltonians. This approach resolves the question and opens the door for the stability analysis of higher order conservative systems, such as flexible satellites, not amenable to traditional tools.

On the Development of Attitude Stabilization and Control System of a Japanese Scientific Satellite

ISAS' experience and future plan in attitude control of scientific satellites are briefly reviewed. The mission and the attitude requirement are explained for scientific satellite EXOS-C that is scheduled for launch in February 1984 by Mu-3S vehicle. The attitude control is implemented by a bias-momentum stabilized Sun-pointing system employing magnetic torquing. The detail of the design is presented, and the development and test approach of the control system is described in relation to the Japanese scientific satellite project at ISAS, Univ. of Tokyo

Attitude stability of a spinning symmetric satellite in a planar periodic orbit

This paper contains an analysis of the attitude stability of a spinning axisymmetric satellite whose mass center moves in any known planar periodic orbit of the restricted three-body problem while the spin axis remains normal to the orbit plane. A procedure based on Floquet theory is developed for constructing attitude instability charts, and examples of these are presented for two stable periodic orbits of the Earth-Moon system—one direct and one retrograde. The physical significance of these instability predictions is then explored by means of numerical integration of the full nonlinear equations of motion. Finally, an analysis based on averaging is performed, leading to approximate instability charts and indicating a possible connection between certain orbital-attitude resonance conditions and unstable attitude motions.

The Dynamic Stability of a Dual-Spin Satellite

The attitude stability of a dual-spin satellite containing energy disipators on both bodies is investigated. Following Mingori, a symmetrical configuration of the satellite with a mass-spring-dashpot damper on each part is considered, and some new stability results are derived by the application of the Routh-Hurwitz criterion. lt is indicated that the Routh-Hurwitz criterion gives only sufficient conditions of stability for the dual-spin satellite considered. A criterion which is believed to represent both the necessary and sufficient condition of stability is presented here and this is used to check the stability of two specific designs of the dual-spin satellite.

Stability of motion of a space vehicle under constantly acting disturbances

The attitude stability of an Earth-orbiting satellite experiencing aerodynamic torque is studied. This is accomplished by applying the theory of total stability (or, stability under constantly acting disturbances) to the equations of motion. The satellite is gravity-gradient stabilized and a damping torque is incorporated. The aerodynamic torque results from the presence of two flat panels attached to the cylindrical body of the vehicle. This perturbing torque is treated as an additive disturbance in Euler's equations of motion. A Lyapunov function is constructed and then used in an appropriate theorem on stability under constantly acting disturbances. Explicit expressions are thereby found for bounds on a hypothetical initial condition (a rotation from the Earth-pointing equilibrium) and on the aerodynamic torque, so that if these disturbances are less than their respective bounds then the resulting attitude motion of the satellite will not exceed a pre-assigned value. These bounds depend on that pre-assigned value, and on the physical parameters of the satellite. The design implications of these bounds are then discussed.

Attitude Stabilization of Geostationary Satellite with a Single Degree of Freedom Angular Momentum Wheel System

Control of three-axis stabilized geostationary satellite without permanent yaw sensing requires an internal angular momentum control of yaw attitude. When the angular momentum is rigidly aligned with the pitch satellite axis, high pointing accuracy requirements impose a North-South station keeping. When the angular momentum has at least one lateral degree of freedom in satellite axes, high pointing accuracies can be achieved even without North-South station keeping. The comparison of one-degree and two degrees of freedom systems shows that both have about the same performances while one-degree-of-freedom systems are much simpler from the hardware point of view. Various mechanizations of the latter are proposed with special emphasis on skewed momentum wheel configurations.

Author's Reply to "Comments on 'The Use of a Spinning Dissipator for Attitude Stabilization of Earth-Orbiting Satellites'"1

The claims made by Grasshoff in his recent comment on the spinning stabilizer are only heuristic in nature and the claims are found to be in error because the body of dual-spin stabilization theory developed during the past decade and on which Grasshoff's main defence is based was proved to be erroneous.

Stability Analysis of Flexible Spacecraft via the Method of Integral Coordinates

This paper presents an extension of the method of integral coordinates to the stability analysis of hybrid dynamical systems containing two- and three-dimensional elastic members. A common approach to such problems consists of system discretization by means of series representation in terms of admissible functions, an approach involving lengthy computations. By contrast, the method of integral coordinates yields stability criteria with relative ease and in a form that permits ready physical interpretation. As an application, the attitude stability of a force-free satellite containing a membrane is investigated and closed-form stability criteria are derived.

Comments on "The Use of a Spinning Dissipator for Attitude Stabilization of Earth-Orbiting Satellites"

The spacecraft nutation damping performance claimed as a result of the analysis in a recent paper by Sen is invalid because the system equations are incorrect. This correspondence points out some serious omissions in Sen's equations and presents the correct equations whose solution shows that Sen's stabilizer is actually destabilizing.

An Addendum to "The Use of a Spinning Dissipator for Attitude Stabilization of Earth-Orbiting Satellites"

This addendum to an earlier paper1 considers the possibility of obtaining a more appropriate value of the damping time constant T from the knowledge of the characteristic roots. The method used is based on postulating an exponential time function to describe the decay of spacecraft nutation. It is indicated that the present values of T are in closer agreement with those determined approximately in the previous paper.

Attitude Stability of a Dual-Spin Satellite with a Large Flexible Solar Array

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