In a method of controlling a spacecraft (2) having a state x(t) by means of a control u(t), t being the time, during an atmospheric entry, a cost function depending on x(t), u(t) and t is defined in drag-energy dynamics. State constraints to the state x(t) and control constraints to the control u(t) are defined as drag-energy constraints, the state constraints including a starting state and terminal constraints. Determining a minimum of the cost function is transferred into a convex problem by introducing a set of variables corresponding to a reciprocal of drag acceleration. Then, the minimum of the cost function is determined as a drag-energy profile considering the state and constraints. The drag-energy profile is transformed into longitudinal states of the spacecraft (2). Then, that control(t) is applied to the spacecraft (2) that adjusts the longitudinal states of the spacecraft (2) which result in the determined minimum of the cost function.
Sagliano, M., Mooij, E. (2017). METHOD, APPARATUS AND SPACECRAFT FOR CONSTRAINED ATMOSPHERIC ENTRY.
METHOD, APPARATUS AND SPACECRAFT FOR CONSTRAINED ATMOSPHERIC ENTRY
Marco Sagliano;
2017
Abstract
In a method of controlling a spacecraft (2) having a state x(t) by means of a control u(t), t being the time, during an atmospheric entry, a cost function depending on x(t), u(t) and t is defined in drag-energy dynamics. State constraints to the state x(t) and control constraints to the control u(t) are defined as drag-energy constraints, the state constraints including a starting state and terminal constraints. Determining a minimum of the cost function is transferred into a convex problem by introducing a set of variables corresponding to a reciprocal of drag acceleration. Then, the minimum of the cost function is determined as a drag-energy profile considering the state and constraints. The drag-energy profile is transformed into longitudinal states of the spacecraft (2). Then, that control(t) is applied to the spacecraft (2) that adjusts the longitudinal states of the spacecraft (2) which result in the determined minimum of the cost function.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
