This paper presents a new approach to vibration reduction of >exible spacecraft during attitude control by using pulse width pulse frequency (PWPF) modulator for thruster Cring and smart materials for active vibration suppression. The experiment was conducted on the Naval Postgraduate School (NPS)’s >exible spacecraft simulator (FSS), which consists of a central rigid body and an L-shape >exibl...

This paper presents a new approach to vibration reduction of flexible spacecraft during attitude control by using Pulse Width Pulse Frequency (PWPF) Modulator for thruster firing and smart materials for active vibration suppression. The experiment was conducted on the Naval Postgraduate School (NPS) 's Flexible Spacecraft Simulator (FSS) , which consists of a central rigid body and an L-shape f...

Variable speed control moment gyros (VSCMGs) distinguish themselves from the conventional CMGs by having extra degrees of freedom to control the wheel spin in addition to the gimbal angles. Thus, they can be adopted to achieve additional objectives, such as energy storage, as well as attitude control. VSCMGs are ideal for integrated power and attitude control systems (IPACS). The gimbal rates o...

A novel testbed is introduced to examine the problem of multiple spacecraft interacting in close proximity in a laboratory setting. This testbed enables validation of guidance, navigation and control (GNC) algorithms by combining six-degrees of freedom (DoF) computer simulation and three-degrees of freedom hardware-in-the-loop experimentation. The 3-DOF spacecraft simulator enables real-time ha...

The Distributed Spacecraft Attitude Control System Simulator is a testbed comprised of two independent spherical air-bearing platforms, useful for formation-flying attitude control simulation. The DSACSS is intended to support a wide range of functions. As such, requiring that all controllers be robust to approximations of the system parameters is impractical. We document the development of bat...

The problem of reorienting a spacecraft in to acquire a moving target is investigated. The spacecraft is modeled as a rigid body with N axisymmetric wheels controlled by axial torques, and the kinematics are represented by Modified Rodriques Parameters. The trajectory, denoted the reference trajectory, is one generated by a virtual spacecraft that is identical to the actual spacecraft. The open...

It is well known that three momentum wheel actuators can be used to control the attitude of a rigid spacecraft and that arbitrary reorientation maneuvers of the spacecraft can be accomplished using smooth feedback. If failure of one of the momentum wheel actuators occurs, we demonstrate that two momentum wheel actuators can be used to control the attitude of a rigid spacecraft and that arbitrar...

This paper proposed a nonlinear robust control for spacecraft attitude based on passivity and disturbance suppression vector. The spacecraft model was described using quaternion. The control law introduced the suppression vector of external disturbances and had no information related to the system parameters. The desired performance of spacecraft attitude control could be achieved using the des...

high-precision three-axis attitude control scheme is vitally important to deal with the overactuated spacecraft, as long as the overall performance through rapid response can be in general acquired. due to the fact that the rigid-flexible spacecraft is somehow applicable, in so many academic and real environments, there is a consensus among experts of this field that the new insights in develop...