Abstract: Methods and systems are provided for reducing angular velocity of a vehicle using a gyroscope array. A method comprises dithering a gyroscope of the gyroscope array, obtaining current through a gimbal motor of the gyroscope while dithering the gyroscope, determining a gimbal rate command to reduce angular velocity of the vehicle based on the current through the gimbal motor obtained while dithering the gyroscope, and operating the gimbal motor of the gyroscope based on the gimbal rate command.

Abstract: Methods and systems are provided for reducing angular velocity of a vehicle using a gyroscope array. A method comprises dithering a gyroscope of the gyroscope array, obtaining current through a gimbal motor of the gyroscope while dithering the gyroscope, determining a gimbal rate command to reduce angular velocity of the vehicle based on the current through the gimbal motor obtained while dithering the gyroscope, and operating the gimbal motor of the gyroscope based on the gimbal rate command.

Abstract: Methods and systems are provided for reorienting an agile vehicle, such as a satellite or spacecraft, using a control moment gyroscope (CMG) array. The CMG array comprises a plurality of CMGs onboard the agile vehicle. A method comprises obtaining an input torque command for reorienting the vehicle using the CMG array and, when the angular momentum of the CMG array violates or is approaching a momentum boundary criterion, decreasing the input torque command in the kinetic momentum direction, resulting in a modified torque command, and operating the CMG array using the modified torque command.

Abstract: Methods and systems are provided for reorienting an agile vehicle, such as a satellite or spacecraft, using a control moment gyroscope (CMG) array. The CMG array comprises a plurality of CMGs onboard the agile vehicle. A method comprises obtaining an input torque command for reorienting the vehicle using the CMG array and, when the angular momentum of the CMG array violates or is approaching a momentum boundary criterion, decreasing the input torque command in the kinetic momentum direction, resulting in a modified torque command, and operating the CMG array using the modified torque command.

Abstract: The present method provides a method for avoiding singularities in the movement of CMGs in an array of CMGs in a spacecraft. In a first step, a torque command representing a desired torque to produce an attitude adjustment for the spacecraft is received. Next, a range-space gimbal rate required to produce the desired torque based on the desired torque and a Jacobian matrix is calculated. Then, a null-space gimbal rate that assists in the avoidance of singularities is calculated. The total gimbal rate command is determined by summing the range-space gimbal rate and the null-space gimbal rate. Then, the total gimbal rate command is provided to the CMGs to produce the total gimbal rate.

Abstract: A control system of a spacecraft for controlling two or more sets of collinear control moment gyroscopes (CMGs) comprises an attitude control system. The attitude control system is configured to receive a command to adjust an orientation of the spacecraft, determine an offset for a momentum disk for each of the two or more sets of CMGs that maximizes torque, determine a momentum needed from the two or more sets of CMGs to adjust the orientation of the spacecraft, and calculate a total torque needed by taking the derivative of the momentum. The control system further comprises a momentum actuator control processor coupled to the attitude control system, the momentum actuator control processor configured to calculate a required gimbal movement for each of the CMGs in each of the two or more sets of collinear CMGs from total torque.

Abstract: A momentum-control system for a spacecraft is disclosed. The momentum-control system comprises an attitude-control system. The attitude-control system receives data concerning a desired spacecraft maneuver and determines a torque command to complete the desired spacecraft maneuver. A momentum actuator control processor coupled to the attitude-control system receives the torque command. The momentum actuator control processor calculates a gimbal rate command comprising a range-space gimbal rate required to produce the torque command and a null-space gimbal rate required to maximize the ability to provide torque in the direction of a current torque. At least four control-moment gyros are coupled to the momentum control actuator control processor. Each of the control-moment gyros receives and executes the gimbal rate to produce the desired maneuver.

Abstract: The present method provides a method for avoiding singularities in the movement of CMGs in an array of CMGs in a spacecraft. In a first step, a torque command representing a desired torque to produce an attitude adjustment for the spacecraft is received. Next, a range-space gimbal rate required to produce the desired torque based on the desired torque and a Jacobian matrix is calculated. Then, a null-space gimbal rate that assists in the avoidance of singularities is calculated. The total gimbal rate command is determined by summing the range-space gimbal rate and the null-space gimbal rate. Then, the total gimbal rate command is provided to the CMGs to produce the total gimbal rate.

Abstract: A momentum-control system for a spacecraft is disclosed. The momentum-control system comprises an attitude-control system. The attitude-control system receives data concerning a desired spacecraft maneuver and determines a torque command to complete the desired spacecraft maneuver. A momentum actuator control processor coupled to the attitude-control system receives the torque command. The momentum actuator control processor calculates a gimbal rate command comprising a range-space gimbal rate required to produce the torque command and a null-space gimbal rate required to maximize the ability to provide torque in the direction of a current torque. At least four control-moment gyros are coupled to the momentum control actuator control processor. Each of the control-moment gyros receives and executes the gimbal rate to produce the desired maneuver.