This patent presents an attitude determination and control system based on a Quaternion Kalman Filter (QKF) with an extendable number of sensors and actuators. Furthermore, it is compatible with the spherical motor as its attitude actuator. The system includes a processor with a QKF, at least one direct attitude actuator, and at least two environmental sensors. Firstly, system dynamics calculates a first propagation attitude determination result. Next, update the first propagation with the attitude sensor measurements. Then, control the satellite's attitude via the attitude actuator closer to the attitude command provided by the user. The proposed system dynamic model could adjust the number of actuators and sensors freely without reprogramming the algorithms for new missions with new configurations on the actuators and sensors. Moreover, if some components fail, the algorithm can automatically remove those related sequences to avoid the overall failure of the system.

This patent presents an attitude determination and control system based on a Quaternion Kalman Filter (QKF) with an extendable number of sensors and actuators. Furthermore, it is compatible with the spherical motor as its attitude actuator. The system includes a processor with a QKF, at least one direct attitude actuator, and at least two environmental sensors. Firstly, system dynamics calculates a first propagation attitude determination result. Next, update the first propagation with the attitude sensor measurements. Then, control the satellite's attitude via the attitude actuator closer to the attitude command provided by the user. The proposed system dynamic model could adjust the number of actuators and sensors freely without reprogramming the algorithms for new missions with new configurations on the actuators and sensors. Moreover, if some components fail, the algorithm can automatically remove those related sequences to avoid the overall failure of the system.

A system for vibration control of a cryocooler that cools an imager. The system includes a vibration sensor that is physically affixed to the cryocooler. The vibration sensor senses a physical vibration of the cryocooler and to generates a vibration signal therefrom. The system also includes cryocooler drive electronics operatively coupled to the vibration sensor and the cryocooler. The cryocooler drive electronics output a drive waveform that drives the cryocooler so as to reduce the vibration impact of the cryocooler. The harmonic content of the cryocooler drive waveform is controlled by the cryocooler drive electronics based on the vibration signal.

A system for vibration control of a cryocooler that cools an imager. The system includes a vibration sensor that is physically affixed to the cryocooler. The vibration sensor senses a physical vibration of the cryocooler and to generates a vibration signal therefrom. The system also includes cryocooler drive electronics operatively coupled to the vibration sensor and the cryocooler. The cryocooler drive electronics output a drive waveform that drives the cryocooler so as to reduce the vibration impact of the cryocooler. The harmonic content of the cryocooler drive waveform is controlled by the cryocooler drive electronics based on the vibration signal.

Feedback control circuitry includes rate limiter circuitry configured to generate a rate limited position command based on a position command for a controlled component and based on a speed command for the controlled component. The feedback control circuitry also includes error adjustment circuitry configured to apply a control gain to an error signal to generate an adjusted error signal. The error signal is based on position feedback and the rate limited position command, and the position feedback indicates a position of the controlled component. The feedback control circuitry further includes an output terminal configured to output a current command generated based on the adjusted error signal.

An active composite variable damping rotational control device includes a variable damping module and a power module. The variable damping module includes a magnetorheological fluid tank and a rotational inertia wheel. The rotational inertia wheel is arranged in the magnetorheological fluid tank fully filled with magneorheological fluid. The power module includes a device tubular cavity, a driver, an encoder and a speed changer. The driver is fixed on the inner wall of the device tubular cavity. The driver, the encoder and the speed changer are coaxial. A driving shaft of the driver passes through the speed changer and extends into the magnetorheological fluid tank to be fixed perpendicularly at the center of the rotational inertia wheel. The control effect of the present invention may not be greatly affected by the change of a structural form and the change of an external load.

The present invention relates to an elastic metamaterial for reducing vibrations of a flexible structure such as a main cable of a tether system for controlling an orbit of a satellite revolving around a planet, and a method for improving a vibration reduction performance thereof, and more particularly, to an elastic metamaterial having an improved precision, in which a ratio of a cross-sectional area of a pendulum ring may be adjusted to maintain a frequency characteristic other than a band gap generated due to the elastic metamaterial even in a state where a mass of the pendulum ring is not changed, and a band gap (R_ring) generated due to the pendulum ring of the elastic metamaterial and a band gap (R_beam) generated due to the elastic beams may be combined into one band gap to expand a vibration damping range, and a method for improving a vibration reduction performance thereof.

A space vehicle includes one or more magnetorquers operable to change an attitude of the space vehicle in an external magnetic field, each magnetorquer comprising a coil, and a switching circuit for short-circuiting the coil of at least one of the magnetorquers so that a closed electric circuit comprising said coil is formed, for damping tumbling motion of the space vehicle in the external magnetic field. The switching circuit is configured to short-circuit the coil of the at least one magnetorquer upon occurrence of a condition indicative of end-of-life or failure of the space vehicle. The application further relates to a corresponding method of operating a space vehicle.

An active composite variable damping rotational control device includes a variable damping module and a power module. The variable damping module includes a magnetorheological fluid tank and a rotational inertia wheel. The rotational inertia wheel is arranged in the magnetorheological fluid tank fully filled with magneorheological fluid. The power module includes a device tubular cavity, a driver, an encoder and a speed changer. The driver is fixed on the inner wall of the device tubular cavity. The driver, the encoder and the speed changer are coaxial. A driving shaft of the driver passes through the speed changer and extends into the magnetorheological fluid tank to be fixed perpendicularly at the center of the rotational inertia wheel. The control effect of the present invention may not be greatly affected by the change of a structural form and the change of an external load.

A projectile intended for damping a spacecraft (100) comprising a main body (110) and active attitude control means (150) comprises a harpoon and is intended to equip a space delivery vehicle to be projected towards the spacecraft. It comprises a passive damper (200) mounted such that it is fixed on the harpoon and suitable for generating, in cooperation with the Earth's magnetic field, a damping torque. That passive damper (200) comprises an outer enclosure (210) and an inner body (220) configured such that: the inner body, permanently magnetized, is positioned inside the outer enclosure and is capable of moving in rotation about at least one axis of rotation, the outer enclosure and the inner body comprise respectively an inner surface and an outer surface, separated by means of a viscous fluid, the outer enclosure is fixed to the main body of the spacecraft for rotation therewith once the harpoon is secured to the main body.