초록

A hot-gas thruster is actuated using a relatively small electric motor. The hot-gas thruster includes a pressure assisted pilot shaft to keep electric power demand to only a few hundred watts peak and only tens of watts on average, while exhibiting relatively fast response times.

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1. A hot-gas thruster, comprising: an electric motor operable to selectively supply a drive force;a thruster body having an inlet port, an outlet port, and an inner surface that defines a valve chamber, the inlet port for receiving a flow of hot gas, the outlet port defining a valve seat and a thrus

1. A hot-gas thruster, comprising: an electric motor operable to selectively supply a drive force;a thruster body having an inlet port, an outlet port, and an inner surface that defines a valve chamber, the inlet port for receiving a flow of hot gas, the outlet port defining a valve seat and a thrust nozzle;a poppet valve disposed at least partially within the valve chamber and including a control surface, a seating surface, an outer surface between the control surface and the seating surface, and a vent orifice in fluid communication with the outlet port, the poppet valve defining a control chamber between the control surface and the inner surface of the thruster body, the control chamber in continuous fluid communication with the inlet port via a fill orifice, the poppet valve movable between a closed position, in which the seating surface engages the valve seat, and a plurality of open positions, in which the seating surface does not engage the valve seat;a suspension spring housing coupled to the poppet valve;a pilot shaft extending through the suspension spring housing and into the poppet valve, the pilot shaft coupled to receive the drive force from the electric motor and responsive thereto to selectively move in either a first direction or a second direction;a pair of preload springs disposed within the suspension spring housing, the preload springs engaging both the suspension spring housing and the pilot shaft and supplying opposing preload forces thereto,wherein: when the pilot shaft moves in the first direction, fluid pressure in the control chamber is vented via the vent orifice to allow the poppet valve to move toward an open position, andwhen the pilot shaft moves in the second direction, fluid pressure in the control chamber aids the pilot shaft to move the poppet valve toward the closed position. 2. The hot-gas thruster of claim 1, wherein the poppet valve further comprises an internal cavity into which the pilot shaft extends, the internal cavity in continuous fluid communication with the control chamber. 3. The hot-gas thruster of claim 2, wherein the poppet valve further comprises a chamber-to-cavity orifice that provides the continuous fluid communication between the internal cavity and the control chamber. 4. The hot-gas thruster of claim 1, wherein: the suspension spring housing comprises an inner surface that defines a first housing engagement surface and a second housing engagement surface;the pilot shaft comprises a radially extending flange, the flange including a first flange engagement surface and an opposing second flange engagement surface;one of the pair of preload springs engages the first housing engagement surface and the first flange engagement surface; andanother of the pair of preload springs engages the second housing engagement surface and the second flange engagement surface. 5. The hot-gas thruster of claim 1, wherein the fill orifice is formed in the thruster body. 6. The hot-gas thruster of claim 1, wherein the fill orifice is formed in the poppet valve. 7. The hot-gas thruster of claim 1, wherein at least portions of the thrust nozzle and control surface define a supersonic nozzle. 8. The hot-gas thruster of claim 1, further comprising one or more gears disposed between the electric motor and the pilot shaft. 9. The hot-gas thruster of claim 1, further comprising a motor position sensor coupled to the electric motor and configured to sense electric motor rotational position. 10. The hot-gas thruster of claim 1, further comprising a valve position sensor coupled to the poppet valve and configured to sense poppet valve position. 11. A hot-gas thruster control system, comprising: an electric motor configured to be selectively energized and operable, upon being energized, to supply a drive force;a control configured to selectively energize the electric motor;a thruster body having an inlet port, an outlet port, and an inner surface that defines a valve chamber, the inlet port for receiving a flow of hot gas, the outlet port defining a valve seat and a thrust nozzle;a poppet valve disposed at least partially within the valve chamber and including a control surface, a seating surface, an outer surface between the control surface and the seating surface, and a vent orifice in fluid communication with the outlet port, the poppet valve defining a control chamber between the control surface and the inner surface of the thruster body, the control chamber in continuous fluid communication with the inlet port via a fill orifice, the poppet valve movable between a closed position, in which the seating surface engages the valve seat, and a plurality of open positions, in which the seating surface does not engage the valve seat;a suspension spring housing coupled to the poppet valve;a pilot shaft extending through the suspension spring housing and into the poppet valve, the pilot shaft coupled to receive the drive force from the electric motor and responsive thereto to selectively move in either a first direction or a second direction;a pair of preload springs disposed within the suspension spring housing, the preload springs engaging both the suspension spring housing and the pilot shaft and supplying opposing preload forces thereto,wherein: when the pilot shaft moves in the first direction, fluid pressure in the control chamber is vented via the vent orifice to allow the poppet valve to move toward an open position, andwhen the pilot shaft moves in the second direction, fluid pressure in the control chamber aids the pilot shaft to move the poppet valve toward the closed position. 12. The hot-gas thruster control system of claim 11, further comprising a motor position sensor coupled to the electric motor, the motor position sensor configured to sense electric motor rotational position and supply a rotational position signal representative thereof to the control. 13. The hot-gas thruster control system of claim 11, wherein the poppet valve further comprises: an internal cavity into which the pilot shaft extends, the internal cavity in continuous fluid communication with the control chamber; anda chamber-to-cavity orifice that provides the continuous fluid communication between the internal cavity and the control chamber. 14. The hot-gas thruster control system of claim 11, wherein: the suspension spring housing comprises an inner surface that defines a first housing engagement surface and a second housing engagement surface;the pilot shaft comprises a radially extending flange, the flange including a first flange engagement surface and an opposing second flange engagement surface;one of the pair of preload springs engages the first housing engagement surface and the first flange engagement surface; andanother of the pair of preload springs engages the second housing engagement surface and the second flange engagement surface. 15. The hot-gas thruster control system of claim 11, wherein the fill orifice is formed in the thruster body. 16. The hot-gas thruster control system of claim 11, wherein the fill orifice is formed in the poppet valve. 17. The hot-gas thruster control system of claim 11, wherein at least portions of the thrust nozzle and control surface define a supersonic nozzle. 18. The hot-gas thruster control system of claim 11, further comprising one or more gears disposed between the electric motor and the pilot shaft. 19. The hot-gas thruster control system of claim 11, further comprising a valve position sensor coupled to the poppet valve, the valve position sensor configured to sense poppet valve position and supply a valve position signal representative thereof to the control. 20. A hot-gas thruster, comprising: a thruster body having an inlet port, an outlet port, and an inner surface that defines a valve chamber, the inlet port for receiving a flow of hot gas, the outlet port defining a valve seat and a thrust nozzle;a poppet valve disposed at least partially within the valve chamber and including a control surface, a seating surface, an outer surface between the control surface and the seating surface, an internal cavity, a chamber-to-cavity orifice, and a main vent orifice in fluid communication with the outlet port, the poppet valve defining a control chamber between the control surface and the inner surface of the thruster body, the control chamber in continuous fluid communication with the internal cavity via the chamber-to-cavity orifice and in continuous fluid communication with the inlet port via a fill orifice, the poppet valve movable between a closed position, in which the seating surface engages the valve seat, and a plurality of open positions, in which the seating surface does not engage the valve seat;a suspension spring housing coupled to the poppet valve, the suspension spring housing comprising an inner surface that defines a first housing engagement surface and a second housing engagement surface;a pilot shaft extending through the suspension spring housing and into the internal cavity of the poppet valve, the pilot shaft comprising a radially extending flange including a first flange engagement surface and an opposing second flange engagement surface, the pilot shaft adapted to receive a drive force and responsive thereto to selectively move in either a first direction or a second direction;a first preload spring disposed within the suspension spring housing, the first preload spring engaging the first housing engagement surface and the first flange engagement surface and supplying a first preload force thereto; anda second preload spring disposed within the suspension spring housing, the second preload spring engaging the second housing engagement surface and the second flange engagement surface and supplying a second preload forces thereto,wherein: when the pilot shaft moves in the first direction, fluid pressure in the control chamber is vented via the vent orifice to allow the poppet valve to move toward an open position, andwhen the pilot shaft moves in the second direction, fluid pressure in the control chamber aids the pilot shaft to move the poppet valve toward the closed position.