Honeywell International Inc.

Ithaco Space Systems, Inc.

Mason A Peck

Brian H Hamilton

Brian K Underhill

Michael Ray Elgersma

Daniel P Johnson

Blaise Grayson Morton

Gunter Stein

Jack Howard Jacobs

Tristram Tupper Hyde

William Edward Bialke

Dennice F Gayme

Brian J Hamilton

J Jeff Bonn

Robert J Hart

Leah R Soffer

A control moment gyroscope system for delivering a target torque to a spacecraft including a rotor assembly having a rotor and a motor to spin the rotor about a rotor axis. A gimbal assembly has a gimbal for supporting the rotor assembly and a gimbal torque motor to rotate the gimbal about a gimbal axis, which is normal to the rotor axis, to generate an output torque. A control system has a sensor for determining the output torque and a processor in communication with the rotor assembly, the gimbal assembly and the sensor. The processor requests the target torque and establishes a feedback control loop to generate a torque error signal based on the output torque for bringing the output torque within a predetermined range of the target torque.

Direct torque actuator control for control moment gyroscope

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.

Method and system for controlling sets of collinear control moment gyroscopes with offset determination without attitude trajectory of spacecraft

Methods and apparatus are provided for reorienting control moment gyros (CMGs) to compensate for CMG failure or change in spacecraft (S/C) mass properties or mission. An improved CMG comprises a drive means for rotating the CMG around an axis not parallel to the CMG gimbal axis. Releasable clamps lock the CMG to the spacecraft except during CMG array reorientation. CMGs arrays are combined with attitude sensors, a command module, memory for storing data and programs, CMG drivers and sensors (preferably for each CMG axis), and a controller coupling these elements. The method comprises determining whether a CMG has failed or the S/C properties or mission changed, identifying the working CMGs of the array, determining a new array reorientation for improved spacecraft control, unlocking, reorienting and relocking the CMGs in the array and updating the S/C control parameters for the new array orientation.

Dynamic CMG array and method

Methods and apparatus are provided for reaction wheel (RW) assemblies for spacecraft. The apparatus comprises a M/G coupled to an inertia wheel and a controller coupled to the M/G that, in response to commands it receives, couples power to or from an M/G of another RW assembly over a shared transfer connection (V), so that one M/G acts as a generator powering another M/G acting as a motor. The controller compares generator voltage Vto the BEMF of the motor on Vand reconfigures a multi-winding M/G or steps-up the generated voltage to maintain V&#x3e;Vto maximize direct energy transfer from one RW to the other as long as possible. When Vdeclines sufficiently, the controller can couple the motor to the spacecraft power bus and/or the generator to a power dump so as to continue to provide the commanded torque if needed. Operation is automatic.

High-torque, low power reaction wheel array and method

A method for avoiding singularities in the movement of CMGs in an array of CMGs in a spacecraft includes a first step where a maneuver command to rotate a spacecraft orientation is received. Then, the torque needed to rotate the spacecraft's orientation is determined. Then, the torque is integrated to determine a momentum path. The momentum path is decomposed into a sequence of straight line segments. For each line segment, a unit vector along the straight line segments is determined. Then, it is determined if there is a continuous path connecting a start point and an end point of the line segment in a plane perpendicular to the unit vector. For each point along the path in the plane perpendicular to the unit vector, a set of gimbal angles is determined.

Method and system for determining a singularity free momentum path

An spacecraft control system is provided that includes a tube and a plurality of microwheels. The plurality of microwheels is disposed within the tube. Each microwheel has a first stator wafer, a second stator wafer, and a rotor wafer disposed therebetween. The first and second stator wafers are configured to spin the rotor wafer.

Momentum tube for distributed actuation

A momentum actuator for steering a spacecraft is disclosed. The momentum actuator comprises a rotor, a gimbal upon which the rotor is mounted, and a stepper motor coupled to the gimbal and operable to rotate the rotor about the gimbal in a series of steps. In one embodiment of the present invention the spin rate of the rotor can be varied to provide torque.

Quantized control-moment gyroscope array

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.

Method and system for CMG array singularity avoidance

A momentum-control system comprising a plurality of momentum actuators and a platform upon which the plurality of momentum actuators are mounted. The momentum control system further comprises a plurality of active struts mounted on the bottom side of the platform. The active struts are configured to produce a force to steer the plurality of momentum actuators and the platform to produce forces and moments for spacecraft attitude control and disturbance suppression.

Method and system for steering a momentum control system

A disturbance-cancellation system and method is provided that facilitates the adaptive cancellation of periodic disturbances. The disturbance-cancellation system and method includes a pair of control moment gyroscopes (CMGs) arranged together as a scissored pair. The scissored pair of CMGs is used to create a periodic torque with a controllable amplitude and frequency. The periodic torque created by the CMGs is adaptively controlled to cancel out periodic disturbances in the system. The system and method creates a periodic torque with a controllable amplitude and frequency by rotating the inner-gimbal assemblies of the CMGs in opposite directions at substantially equal phase and angular velocity. Amplitude matching can be achieved by adjusting the rotor spin rate. The steady-state constant motion results in a periodic torque along the output axis of the scissored pair, while components of torque along axes orthogonal to this one cancel out.

System and method for adaptive cancellation of disturbances

A spacecraft system including a spacecraft assembly or 'stack' having an upper stage of a rocket-powered launch vehicle providing a final boost phase during launch. The stack also includes a payload structure rotatably interconnected with the upper stage. The upper stage and the payload structure together define a central axis that is generally coincident with the thrust axis during launch. The stack has an axis of maximum moment of inertia that is not parallel to the central axis. The stack has internal damping such that unstable nutation occurs if the upper stage and the payload structure rotate together about the central axis at the same rotational rate and in the same direction. The system includes a controller that rotates the payload structure relative to the upper stage during the final boost phase to alleviate coning motion of the stack.

Momentum stabilized launch vehicle upper stage

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.

Method and system for optimizing torque in a CMG array

An attitude determination system and method is provided that includes at least two sensor sets. Each sensor set is configured to detect electromagnetic radiation, such as light of a known frequency. Specifically, each sensor set is configured to detect electromagnetic radiation from a one of a plurality of point sources, where each of the plurality of point sources emits electromagnetic radiation of a different frequency. Each sensor set includes at least three sensors, with each of the three sensors having a different orientation. The three sensors in the sensor set are used to determine a relative orientation of the vehicle with respect to one of the point sources. The at least two sensor sets in the system determine the relative orientation with respect to at least two point sources. By placing the sensors on a vehicle and knowing the direction to the point sources in a reference frame coordinate system, the orientation of the vehicle with respect to this reference frame can be estimated.

Attitude determination system and method

A momentum control system and method is provided that provides attitude control for a vehicle while minimizing the negative effects of the momentum control system. The momentum control system and method include at least one more reaction wheel than the degrees of freedom under control. For example, in a vehicle designed to rotate in all three direction, at least four reaction wheels would be provided. The additional reaction wheel provide an additional control parameter that can be used to minimize the cost of the momentum control system's performance. The cost of the momentum control system that can be minimized includes the effects of vibration, power consumption, and undesirable changes in rotational direction, among others.

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Scottsdale, AZ, United States of America

Mason A Peck