Spacecraft docking system

Patent metadata

Field	Value
Publication number	US-9302793-B2
Application number	US-201414221357-A
Country	US
Kind code	B2
Filing date	Mar 21, 2014
Priority date	Mar 21, 2014
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A method and apparatus for docking a spacecraft. The apparatus comprises elongate members, movement systems, and force management systems. The elongate members are associated with a docking structure for a spacecraft. The movement systems are configured to move the elongate members axially such that the docking structure for the spacecraft moves. Each of the elongate members is configured to move independently. The force management systems connect the movement systems to the elongate members and are configured to limit a force applied by the each of the elongate members to a desired threshold during movement of the elongate members.

First claim

What is claimed is:

1. An apparatus comprising:
a state machine connected to a force management system;
a first ball screw connected to a base plate configured to connect to a spacecraft, the first ball screw connected to a first power transfer device directly connected to a first movement system configured to receive a first command to move the first ball screw at a first rate such that the first ball screw comprises a first rate of axial movement;
a second ball screw connected to the base plate and to a second power transfer device directly connected to a second movement system configured to receive a second command to move the second ball screw at a second rate such that the second ball screw comprises a second rate of axial movement, the second rate of axial movement being independent of the first rate of axial movement, such that the first power transfer device comprises a first torque limit determined independent of any intervention from any electronic control system, control law, and software application, in at least one of: the spacecraft, another spacecraft, and a combination thereof, and the second power transfer device comprises a second torque limit determined independent from: the first torque limit, the first command, and any intervention from the any electronic control system, control law, and software application.

2. The apparatus of claim 1 , further comprising the base plate connected to a docking structure configured such that in operation the docking structure connects the spacecraft to a second structure selected from one of a docking ring, a space station, a satellite, and a second spacecraft.

3. The apparatus of claim 2 , further comprising each power transfer device configured, such that in operation, each power transfer device independently and passively limits a respective force applied by each ball screw respectively in response to a load, applied by the second structure, against each ball screw respectively.

4. The apparatus of claim 2 further comprising:
an attachment system configured to secure the docking structure to the second structure.

5. The apparatus of claim 2 , wherein the docking structure is selected from one of a capture ring and a rod.

6. The apparatus of claim 2 , further comprising each ball screw configured, such that in operation, movement of the docking structure comprises a number of degrees of freedom.

7. The apparatus of claim 2 , wherein the docking structure comprises a mating interface and a group of alignment features.

8. The apparatus of claim 1 , each movement system configured to operate in a state determined by the state machine and selected from at least one of: extension, attenuation, or retraction.

9. The apparatus of claim 1 , wherein each power transfer device comprises at least one of: a slip clutch, a hydraulic clutch, an electromagnetic clutch, an electromagnetic motor, software, and an electronic controller.

10. The apparatus of claim 1 , wherein the movement systems each comprise a respective motor configured to move a corresponding elongate member at a commanded rate.

11. The apparatus of claim 10 , further comprising each respective motor configured to reduce a rate of movement of the corresponding elongate member based on a load placed on the corresponding elongate member.

12. The apparatus of claim 10 , wherein at least one power transfer device comprises a slip clutch configured to slip when the force reaches a desired threshold such that the corresponding elongate member moves from a first position to a second position.

13. A method for docking a spacecraft, the method comprising:
moving elongate members axially such that a docking structure for the spacecraft moves, wherein each of the elongate members moves independently; and
limiting a force applied by the each of the elongate members to a desired threshold during movement of the elongate members via using:
a first ball screw connected to a first elongate member of the elongate members, and to a base plate configured to connect to the spacecraft, the first ball screw connected to a first power transfer device directly connected to a first movement system configured to receive a first command to move the first ball screw at a first rate such that the first ball screw comprises a first rate of axial movement; and
a second ball screw connected to a second elongate member of the elongate members, and to the base plate and to a second power transfer device directly connected to a second movement system configured to receive a second command to move the second ball screw at a second rate such that the second ball screw comprises a second rate of axial movement, the second rate of axial movement being independent of the first rate of axial movement, such that the first power transfer device comprises a first torque limit determined independent of any intervention from any electronic control system, control law, and software application, in at least one of: the spacecraft, another spacecraft, and a combination thereof, and the second power transfer device comprises a second torque limit determined independent from: the first torque limit, the first command, and any intervention from the any electronic control system, control law, and software application.

14. The method of claim 13 further comprising:
connecting the docking structure to a second structure using an attachment system.

15. The method of claim 13 , wherein limiting the force comprises:
passively limiting the force applied by the each of the elongate members in response to a load applied by a second structure.

16. The method of claim 13 further comprising:
reducing a rate of movement of a motor of a corresponding movement system based on a load placed on a corresponding elongate member.

17. A docking system for a spacecraft comprising:
elongate members physically connected to a capture ring;
a first ball screw connected to a first elongate member of the elongate members, and to a base plate configured to connect to the spacecraft, the first ball screw connected to a first power transfer device directly connected to a first movement system configured to receive a first command to move the first ball screw at a first rate such that the first ball screw comprises a first rate of axial movement; and
a second ball screw connected to a second elongate member of the elongate members, and to the base plate and to a second power transfer device directly connected to a second movement system configured to receive a second command to move the second ball screw at a second rate, such that the second ball screw comprises a second rate of axial movement, the second rate of axial movement being independent of the first rate of axial movement, such that the first power transfer device comprises a first torque limit determined independent of any intervention from any electronic control system, control law, and software application, in at least one of: the spacecraft, another spacecraft, and a combination thereof, and the second power transfer device comprises a second torque limit determined independent from: the first torque limit, the first command, and any intervention from the any electronic control system, control law, and software application;
alignment features positioned along a mating surface of the capture ring and configured to align the capture ring with a second structure; and
force management systems connecting the motors to the elongate members and configured to limit a force applied by the each of the elongate members to a desired threshold during movement of the elongate members.

Assignees

• Boeing Co

Inventors

• Ghofranian Siamak
• Chuang Li-Ping Christopher
• Motaghedi Pejmun

Classifications

• B64G1/2229 Primary

  characterised by the deployment actuating mechanism (inflating B64G1/2227) · CPC title

• B64G1/6462 Primary

  characterised by the means for engaging other vehicles · CPC title

• B64G1/222

  for deploying structures between a stowed and deployed state · CPC title

• B64G1/646 Primary

  Docking or rendezvous systems (refuelling in space B64G1/4024) · CPC title