  This paper introduces a continuous formulation for compound state-triggered
constraints, which are generalizations of the recently introduced
state-triggered constraints. State-triggered constraints are different from
ordinary constraints found in optimal control in that they use a
state-dependent trigger condition to enable or disable a constraint condition,
and can be expressed as continuous functions that are readily handled by
successive convexification. Compound state-triggered constraints go a step
further, giving designers the ability to compose trigger and constraint
conditions using Boolean and and or operations. Simulations of the
6-degree-of-freedom (DoF) powered descent guidance problem obtained using
successive convexification are presented to illustrate the utility of
state-triggered and compound state-triggered constraints. The examples employ a
velocity-triggered angle of attack constraint to alleviate aerodynamic loads,
and a collision avoidance constraint to avoid large geological formations. In
particular, the velocity-triggered angle of attack constraint demonstrates the
ability of state-triggered constraints to introduce new constraint phases to
the solution without resorting to combinatorial techniques.
