Solving complex optimal control problems with nonlinear controls using trigonometric functions

Abstract

AbstractThis study investigates the use of trigonometric functions to resolve two major issues encountered when solving practical optimal control problems (OCPs) that are characterized by nonlinear controls. First, OCPs with constraints on nonlinear controls require the solution to a multipoint boundary value problem, which poses additional computational difficulties. Second, in certain unconstrained OCPs with nonlinear controls, the extremum found from the necessary conditions can be opposite than expected (e.g., a maximum instead of a minimum) due to the absence of control options. The aforementioned issues and their effective resolution by using trigonometric functions are explained through two examples including a second‐order system problem and an aerocapture problem of a slender entry vehicle in the Martian atmosphere.