Solution of the Optimal Control Problem Using the Software Package Stomp

Abstract The solution of the constrained optimal control problem (OCP) is considered for aerospace applications. A software package, STOMP (Simultaneous Integrations in the Trajectory Optimization by Mathematiccal Programming package), is described which is used in conjunction with a parameterized optimization program. STOMP is designed to solve the equations of motion (ODE system), evaluating the cost function along with the constraint violations. STOMP then determines the gradients of these functions with respect to each optimization parameter using forward difference estimates. Emphasis is given to the solution of the ODE system including features for reducing computing time in generating the gradient estimates and for designing flexible control function structures including movable grid points. The accuracy achieved in the forward difference estimates of the gradients is discussed particularly in regard to the effect of the integration step size sequence and the perturbation size. A reentry trajectory application is presented.