نتایج جستجو برای: overactuated spacecraft
تعداد نتایج: 11116 فیلتر نتایج به سال:
Electrostatic charging of a spacecraft modifies the distribution of electrons and ions before the particles enter the sensors mounted on the spacecraft body. The floating potential of magnetospheric satellites in sunlight very often reaches several tens of volts, making measurements of the cold (several eV) component of the ambient ions impossible. The plasma electron data become contaminated b...
A batch filter has been designed and analyzed to autonomously determine the orbits of 2 spacecraft based on measurements of the relative position vector from one spacecraft to the other. This system provides a means for high-precision autonomous orbit determination for systems that cannot be dependent on signals from the GPS constellation or ground stations. The filter uses a time series of the...
This work proposes an image-based visual servoing scheme applied to a class of overactuated planar parallel robots with revolute joints. A Proportional Derivative algorithm computes torques for the robot active joints. The Derivative action operates at the joint level and the Proportional action works at the visual level. A linear filter provides velocity estimates from active joint position me...
This paper deals with spacecraft autonomous navigation in deep space missions. The considered problem is that of spacecraft localization based on angular measurements. The dynamic model of the spacecraft accounts for several perturbing effects, such as Earth and Moon gravitational field asymmetry and errors associated with the Moon ephemerides. The measurement process is based on elevation and ...
In this paper, two different algorithms are presented for the estimation of spacecraft body angular rates in the absence of gyro rate data for a star tracker mission. In first approach, body angular rates are estimated with the spacecraft attitude using a dynamical model of the spacecraft. The second approach makes use of a rapid update rate of star camera to estimate the spacecraft body angula...
Torque-saturated control laws for spacecraft attitude control are considered. These control laws require no knowledge of the mass distribution of the spacecraft and thus are inertia-free. We examine two specific problems. In the first problem, the spacecraft has an arbitrary initial attitude and angular velocity, and the objective is to bring the spacecraft to rest with a specified attitude. In...
Anderson, et al. have recently reported the discovery of an apparent anomalous, weak, long-range acceleration in the Pioneer 10/11 and Ulysses spacecraft. I believe that this result can be explained by non-isotropic radiative cooling of the spacecraft electronics through passive radiators on the spacecraft surface. These radiators are preferentially placed on the anti-solar side of the spacecra...
This paper presents a slew maneuver control design of three-axis rotational flexible spacecraft. The focus of the work is to investigate the nonlinear effect of the three axis maneuver for a flexible spacecraft when a vibration suppression technique for linear systems such as input shaping is used in the control design. A simple method of slewing three-axis rotational spacecraft using input sha...
ORBCOMM is a LEO communications spacecraft, providing global point to point packet messaging. Two are in operation now, and the rest of the (eventually 36) constellation design spacecraft are currently in integration and test. The ORBCOMM ACS mission is to point a communications antenna to nadir, while maintaining continuous Sun tracking via spacecraft yaw maneuvers. This mission is achieved us...
The aim is to develop vibration control of flexible spacecraft by adaptive controller. A case study will be carried out which simulates planar motion of flexible spacecraft as a coupled hybrid dynamics of rigid body motion and the flexible arm vibration. The notch filter and adaptive vibration controller, which updates filter and controller parameters continuously from the sensor measurement, a...
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