Method and apparatus for contingency guidance of a CMG-actuated spacecraft
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsIsaac Michael Ross, Donghun Lee, Mark Karpenko
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Abstract
Methods and apparatus are presented for spacecraft operation using non-Eigen axis attitude transitions via control momentum gyroscopes (CMGs) to avoid or mitigate singularities by providing a time-varying attitude command vector including a plurality of time-varying attitude command signals or values representing a plurality of spacecraft states and control trajectories as a guidance command input to an attitude controller of the spacecraft without modifying the spacecraft feedback control law.
Claims20
A method for guiding a spacecraft from an initial state to a final state using a plurality of control momentum gyroscopes (CMGs), the method comprising:
- receiving input data including:
- an initial spacecraft state defining an initial spacecraft attitude vector, an initial spacecraft motion vector, an initial CMG angle vector, and an initial CMG angle rate vector,
- a desired final spacecraft state defining a desired final spacecraft attitude vector, a desired final spacecraft motion vector, a desired final CMG angle vector, and a desired final CMG angle rate vector, and
- at least one constraint defining one or more desired limitations with respect to at least one of spacecraft attitude, spacecraft motion, and CMG operation;
- formulating a control problem based at least partially on the input data;
- solving the control problem to provide a feasible time-varying attitude command vector comprising a plurality of time-varying attitude command signals or values representing a plurality of spacecraft states and control trajectories with respect to one of spacecraft angles, spacecraft angle rates, and spacecraft angle accelerations;
- and
- providing the feasible time-varying attitude command vector as a guidance command input to an attitude controller of the spacecraft.
A non-transitory computer readable medium with computer executable instructions for guiding a spacecraft from an initial state to a final state using a plurality of control momentum gyroscopes (CMGs), the computer readable medium having computer executable instructions for:
- receiving input data including:
- an initial spacecraft state defining an initial spacecraft attitude vector, an initial spacecraft motion vector, an initial CMG angle vector, and an initial CMG angle rate vector,
- a desired final spacecraft state defining a desired final spacecraft attitude vector, a desired final spacecraft motion vector, a desired final CMG angle vector, and a desired final CMG angle rate vector, and
- at least one constraint defining one or more desired limitations with respect to at least one of spacecraft attitude, spacecraft motion, and CMG operation;
- formulating a control problem based at least partially on the input data;
- solving the control problem to provide a feasible time-varying attitude command vector comprising a plurality of time-varying attitude command signals or values representing a plurality of spacecraft states and control trajectories with respect to one of spacecraft angles, spacecraft angle rates, and spacecraft angle accelerations;
- and
- providing the feasible time-varying attitude command vector as a guidance command input to an attitude controller of the spacecraft.
A spacecraft guidance system, comprising:
- at least one processor programmed to:
- receive input data including:
- an initial spacecraft state defining an initial spacecraft attitude vector, an initial spacecraft motion vector, an initial CMG angle vector, and an initial CMG angle rate vector,
- a desired final spacecraft state defining a desired final spacecraft attitude vector, a desired final spacecraft motion vector, a desired final CMG angle vector, and a desired final CMG angle rate vector, and
- at least one constraint defining one or more desired limitations with respect to at least one of spacecraft attitude, spacecraft motion, and CMG operation;
- formulate a control problem based at least partially on the input data;
- solve the control problem to provide a feasible time-varying attitude command vector comprising a plurality of time-varying attitude command signals or values representing a plurality of spacecraft states and control trajectories with respect to one of spacecraft angles, spacecraft angle rates, and spacecraft angle accelerations;
- and
- provide the feasible time-varying attitude command vector as a guidance command input to an attitude controller of the spacecraft.
Dependencies are inferred from the claim text.