Abstract: A gyroscopic boat roll stabilizer for a boat comprises a gimbal, having a gimbal axis, an enclosure mounted to the gimbal and configured to precess about a gimbal axis, a flywheel assembly rotatably mounted inside the enclosure for generating a torque that is applied to counter a rolling motion of the boat, and a braking system for controlling precession of the enclosure.

Abstract: A controller controls precession of a gyroscope that oscillates about a precession axis perpendicular to a spin axis and a roll axis of the gyroscope. To do so, the controller detects a deviation of a center of the oscillation away from a nominal center. The precession is caused by roll of the gyroscope about the roll axis and imposes decreasing amounts of damping upon the roll as the precession moves away from the nominal center. The controller reduces the deviation of the center of the oscillation by applying an asymmetric amount of braking to the precession when the precession and the deviation are in a same direction relative to when the precession and the deviation are in opposing directions.

Abstract: A gyroscopic roll stabilizer comprises a gimbal having a support frame and enclosure configured to maintain a below-ambient pressure, a flywheel assembly including a flywheel and flywheel shaft, one or more bearings for rotatably mounting the flywheel inside the enclosure, a motor for rotating the flywheel, and bearing cooling system for cooling the bearings supporting the flywheel. For smaller units, the bearing cooling system is effective to enable a flywheel with a moment of inertia less than 40,000 lb in2 to be accelerated at a rate of 5 rpm/s or greater. For larger units, the bearing cooling system is effective to enable a flywheel with a moment of inertia greater than 40,000 lb in2 to be accelerated at a rate of 2.5 rpm/s or greater.

Abstract: A gyroscopic roll stabilizer comprises a gimbal having a support frame and enclosure configured to maintain a below-ambient pressure, a flywheel assembly including a flywheel and flywheel shaft, one or more bearings for rotatably mounting the flywheel inside the enclosure, a motor for rotating the flywheel, and bearing cooling system for cooling the bearings supporting the flywheel. For smaller units, the bearing cooling system is effective to enable a flywheel with a moment of inertia less than 40,000 lb in2 to be accelerated at a rate of 5 rpm/s or greater. For larger units, the bearing cooling system is effective to enable a flywheel with a moment of inertia greater than 40,000 lb in2 to be accelerated at a rate of 2.5 rpm/s or greater.

Abstract: A gyroscopic roll stabilizer includes an enclosure, a flywheel assembly, a bearing, a motor, and a bearing cooling circuit. The enclosure is mounted to a gimbal for rotation about a gimbal axis and configured to maintain a below-ambient pressure. The flywheel assembly includes a flywheel and flywheel shaft. The bearing rotatably mounts the flywheel assembly inside the enclosure for rotation about a flywheel axis. The bearing has an inner race and an outer race. The inner race is affixed to the flywheel shaft, and the outer race is held rotationally fixed relative to the enclosure. The motor is operative to rotate the flywheel assembly. The bearing cooling circuit is configured to transfer heat away from the bearing by recirculating cooling fluid along a closed fluid pathway. The gyroscopic roll stabilizer is configured to transfer heat away from the inner and/or outer race of the bearing to the cooling fluid.

Abstract: A gyroscopic boat roll stabilizer for a boat comprises a gimbal, having a gimbal axis, an enclosure mounted to the gimbal and configured to precess about a gimbal axis, a flywheel assembly rotatably mounted inside the enclosure for generating a torque that is applied to counter a rolling motion of the boat, and a braking system for controlling precession of the enclosure.

Abstract: A gyroscopic roll stabilizer for a boat includes a flywheel shaft having a first end and an opposite second end. The flywheel shaft has first and second open-ended cavities formed on opposing ends. A first uneven seal encloses the first cavity, and a second uneven seal encloses the second cavity. The first and second uneven seals are both configured to provide asymmetric sealing such that greater resistance is provided against flow in a primary sealing direction, from a first side toward a second side, than in a secondary sealing direction, from the second side toward the first side. The first side of the second seal faces inward toward the second cavity, and the second side of the first seal faces inward toward the first cavity. The first and second seals are functionally inverted relative to each other. Related methods are also disclosed.

Abstract: A gyroscopic roll stabilizer comprises a gimbal having a support frame and enclosure configured to maintain a below-ambient pressure, a flywheel assembly including a flywheel and flywheel shaft, one or more bearings for rotatably mounting the flywheel inside the enclosure, a motor for rotating the flywheel, and bearing cooling system for cooling the bearings supporting the flywheel. The bearing cooling system enables heat generated by the bearings to be transferred through the flywheel shaft to a heat sink disposed within a cavity in the end of the flywheel shaft, or to a liquid coolant circulating within the cavity.

Abstract: A gyroscopic roll stabilizer for a boat includes an enclosure mounted to a gimbal for rotation about a gimbal axis and configured to maintain a below-ambient pressure, and a flywheel assembly including a flywheel and flywheel shaft, with the flywheel assembly rotatably mounted inside the enclosure for rotation about a flywheel axis. The gyroscopic roll stabilizer also includes a motor operative to rotate the flywheel assembly and disposed inside the enclosure. A motor cooling circuit is configured to transfer heat away from the motor. The motor cooling circuit has a closed fluid pathway for recirculating cooling fluid therein. The fluid pathway includes a fluid channel jointly defined by the motor and the enclosure and having the cooling fluid therein. The gyroscopic roll stabilizer is configured to transfer heat away from the motor to the cooling fluid. Related methods are also disclosed.

Abstract: A gyroscopic roll stabilizer includes an enclosure, a flywheel assembly, and a motor. The enclosure is mounted to a gimbal for rotation about a gimbal axis and configured to maintain a below-ambient pressure. The flywheel assembly is rotatably mounted inside the enclosure for rotation about a flywheel axis. The flywheel assembly includes a flywheel and flywheel shaft. The flywheel shaft has a first end and an opposite second end; a first cavity formed in the first end and facing away from the second end; and a second cavity formed in the second end and facing away from the first end. The flywheel shaft has a longitudinal passage connecting the first cavity and the second cavity. This longitudinal passage may be used for inspection of one of the cavities and/or an associated seal, from the direction of the other cavity. Related methods are also disclosed.

Abstract: A gyroscopic roll stabilizer comprises a gimbal having a support frame and enclosure configured to maintain a below-ambient pressure, a flywheel assembly including a flywheel and flywheel shaft, one or more bearings for rotatably mounting the flywheel inside the enclosure, a motor for rotating the flywheel, and bearing cooling system for cooling the bearings supporting the flywheel. For smaller units, the bearing cooling system is effective to enable a flywheel with a moment of inertia less than 11.7 kg.m2 (40000 lbm in2) to be accelerated at a rate of 5 rpm/s or greater. For larger units, the bearing cooling system is effective to enable a flywheel with a moment of inertia greater than 11.7 kg.m2 (40000 lbm in2) to be accelerated at a rate of 2.5 rpm/s or greater.

Abstract: A gyroscopic boat roll stabilizer for a boat comprises a gimbal, having a gimbal axis, an enclosure mounted to the gimbal and configured to precess about a gimbal axis, a flywheel assembly rotatably mounted inside the enclosure for generating a torque that is applied to counter a rolling motion of the boat, and a braking system for controlling precession of the enclosure. The braking system is configured to enable precession in the first and second directions.

Abstract: A gyroscopic roll stabilizer includes an enclosure, a flywheel assembly, a bearing, a motor, and a bearing cooling circuit. The enclosure is mounted to a gimbal for rotation about a gimbal axis and configured to maintain a below-ambient pressure. The flywheel assembly includes a flywheel and flywheel shaft. The bearing rotatably mounts the flywheel assembly inside the enclosure for rotation about a flywheel axis. The bearing has an inner race and an outer race. The inner race is affixed to the flywheel shaft, and the outer race is held rotationally fixed relative to the enclosure. The motor is operative to rotate the flywheel assembly. The bearing cooling circuit is configured to transfer heat away from the bearing by recirculating cooling fluid along a closed fluid pathway. The gyroscopic roll stabilizer is configured to transfer heat away from the inner and/or outer race of the bearing to the cooling fluid.

Abstract: A gyroscopic boat roll stabilizer for a boat comprises a gimbal, having a gimbal axis, an enclosure mounted to the gimbal and configured to precess about a gimbal axis, a flywheel assembly rotatably mounted inside the enclosure for generating a torque that is applied to counter a rolling motion of the boat, and a braking system for controlling precession of the enclosure. The braking system is configured to enable precession in the first and second directions of up to at least 45 degrees.

Abstract: A gyroscopic roll stabilizer comprises a gimbal having a support frame and enclosure configured to maintain a below-ambient pressure, a flywheel assembly including a flywheel and flywheel shaft, one or more bearings for rotatably mounting the flywheel inside the enclosure, a motor for rotating the flywheel, and bearing cooling system for cooling the bearings supporting the flywheel. The bearing cooling system enables heat generated by the bearings to be transferred through the flywheel shaft to a heat sink disposed within a cavity in the end of the flywheel shaft, or to a liquid coolant circulating within the cavity.