Robust Perturbation Guidance For The Advanced Launch System

Real-Time optimal trajectory generation for constructing guidance laws seems feasible. However, these deterministic guidance schemes maybe sensitive to system and environmental uncertainties. To overcome this deficiecy, it is suggested that the accessory problem about an optimal path, which generates a quadratic cost criterion in the perturbed states and control away from the optimal trajectory, be used as the cost criterion. A modified quadratic cost is to be minimized with respect to the perturbed control but maximized with respect to addive uncertainties in the linearized dynamics and the uncertainty in the linearized measurements. In this way, a robust neighboring optimum scheme is constructed. A perturbed guidance scheme is stated here. To illustrate the theory the second stage of a launch vehicle is considered. An optimal path is generated, and about this path a robust neighboring optimum guidance law is constructed and tested.