A Generalized Algorithm for Inverse Simulation Applied to Helicopter Maneuvering Flight

The inverse simulation problem is discussed in which control inputs that will enable a vehicle to follow a specified trajectory are determined by a numerical teehnioue. The particular technique for inverse simulation which is proposed alleviates some of the problems associated with algorithms which require numerical differentiation of vehicle states in the solution process. The proposed technique emphasizes integration and is presented as a generalized approach to the inverse simulation problem. The algorithm can be applied to problems in which the number of controls exceeds the number of constrained variables. Using a readily available model of a BO‐105 rotorcraft, with linear aerodynamics but with nonlinear inertial cross‐coupling and kinematics, the algorithm is exercised by obtaining the control inputs necessary to enable the rotorcraft to complete a series of discrete maneuvering tasks involving side‐steps, bob‐ups, hurdle‐hops and level turns, each performed with and without a stability augmentation system in operation. A potential application of inverse simulation is the formulation of task‐driven bandwidth requirements for stability augmentation system design.