US 12,312,102 B2
System and method for controlling a motion of a spacecraft in a multi-object celestial system
Abraham Vinod, Cambridge, MA (US); Avishai Weiss, Boston, MA (US); and Stefano Di Cairano, Newton, MA (US)
Assigned to Mitsubishi Electric Research Laboratories, Inc., Cambridge, MA (US)
Filed by Mitsubishi Electric Research Laboratories, Inc., Cambridge, MA (US)
Filed on Dec. 30, 2021, as Appl. No. 17/646,491.
Claims priority of provisional application 63/288,086, filed on Dec. 10, 2021.
Prior Publication US 2023/0182927 A1, Jun. 15, 2023
Int. Cl. B64G 1/24 (2006.01); B64G 1/64 (2006.01)
CPC B64G 1/242 (2013.01) [B64G 1/646 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A controller for controlling a motion of a spacecraft in a multi-object celestial system while avoiding an unauthorized entry into a keep-away zone during a normal and an abnormal operation of the spacecraft, wherein the normal operation includes moving towards a target in the keep-away zone, and wherein the abnormal operation includes one or a combination of a failure to receive an authorization to enter the keep-away zone and a failure of at least one component of the spacecraft, the controller comprising: at least one processor; and a memory having instructions stored thereon that, when executed by the at least one processor, cause the controller to:
execute, during the normal operation of the spacecraft, a nominal control law subject to constraints on maintaining a state of the spacecraft within a union of a plurality of control invariant sets of values of the state of the spacecraft that partially or completely enclose the keep-away zone, wherein the state of the spacecraft includes a location of the spacecraft and at least one or a combination of a velocity and an acceleration of the spacecraft, wherein each of the plurality of control invariant sets is determined such that when the state of the spacecraft is within a control invariant set there is a control command produced by the nominal control law that maintains the state of the spacecraft within the control invariant set despite internal and external forces acting on the spacecraft, wherein the nominal control law solves at each time step, an optimization problem that minimizes a sum of squared distance of the spacecraft to the keep-away zone over time and an amount of energy expended by an open-loop control sequence subject to linear equality constraints describing evolution of a mean and a covariance matrix of a state and a measurement of the spacecraft; and
execute, upon detecting the abnormal operation of the spacecraft, an abort control law associated with the control invariant set including a current state of the spacecraft, wherein at least some different abort control laws are associated with at least some different control invariant sets, and wherein the abort control law is jointly and interdependently determined for the corresponding control invariant set to produce abort control commands moving the spacecraft while avoiding the keep-away zone for any state within the corresponding control invariant set.