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US 4,728,062 AGranted
Pivot actuated nutation damping for a dual-spin spacecraft
AssigneeRCA Corporation
InventorCarl H. Hubert
Life of this patent
Estimating the term…
Abstract
A nutation damping control for a dual-spin satellite is provided by tilting the axis of the rotor relative to the normal spin axis of the satellite and back a half nutation period later. The tilting is in the direction of the angular momentum vector component that is transverse to the rotor's spin axis.
Claims8
An active nutation damping system for a dual-spin spacecraft comprising:
- a spinning body pivotally mounted in a given plane to a platform body with said spinning body pivoted about a pivot axis extending orthogonal to the angular momentum axis of the spacecraft;
- means for sensing motion of the platform body in inertial space about an axis transverse to the spin axis of the spinning body for providing control signals;
- and
- drive means coupled between said spinning body and said platform body and responsive to said control signals for pivoting said spinning body about said pivot axis relative to said platform body a given amount in one direction, and a half nutrition period later pivoting said spinning body said same given amount in the opposite direction to return the spinning body to its original position to produce a reaction moment on the platform body to counter nutational motion thereby providing nutation damping.
1 more element
An active nutation damping system for a dual-spin spacecraft comprising:
- a spinning body pivotally mounted to a platform body in a given plane about a pivot axis where said pivot axis extends orthogonal to the angular momentum axis of the spacecraft;
- means for directly sensing motion of the platform body in inertial space about an axis transverse to the angular momentum axis for providing a first control signal representing angular rate of the platform body about said transverse axis and for providing a second control signal representing the maximum nutation angle;
- drive means coupled between said spinning body and said platform body and responsive to said first and second control signals for, when said first control signal crosses zero, driving said motor to pivot the spinning body a given amount proportional to the sensed nutation angle according to said second control signal in said plane in the general direction of the angular momentum vector component that is transverse to the spinning body's spin axis and a half nutation cycle after said zero crossing driving said motor said same amount in the opposite direction to return the spinning body to its initial position to produce rapid nutation damping.
An active nutation damping system for a dual-spin spacecraft comprising:
- a spinning body pivotally mounted to a platform body in a given plane about a pivot axis where said axis extends orthogonal to the angular momentum axis of the satellite;
- means for directly sensing motion of the platform body in inertial space about an axis transverse to the angular momentum axis for providing a first control signal representing angular rate of the platform body about said transverse axis and for providing a second control signal representing the maximum nutation angle;
- drive means including a stepper motor and motor control means coupled between said spinning body and said platform body and responsive to said first and second control signals for, when said first control signal crosses zero, driving said motor to pivot the spinning body a number of steps proportional to the sensed nutation angle according to said second control signal in said plane in the general direction of the angular momentum vector component that is transverse to the spinning body's spin axis and a half nutation cycle after said zero crossing driving said motor said same amount in the opposite direction to return the spinning body to its initial position to produce rapid nutation damping.
Dependencies are inferred from the claim text.