Real-time computational methods for SDRE nonlinear control of missiles

Abstract

The state dependent Riccati equation (SDRE) technique is a recently developed methodology for designing control laws and estimation algorithms for missile flight control. Although its potential is well recognized by control theory experts, the industry acceptance of the technique has been slow. The main reasons for this are: a) unlike linear control technology, the SDRE approach requires advanced numerical methods for its implementation, which are not currently available off-the-shelf, b) the perception that this technique may not be computationally feasible for real-time implementation on flight control processors.Both of these issues are addressed in this paper. A software package for real-time implementation of the SDRE technique was developed during the present research. The execution of this software at speeds up to 2 kHz sample rates on problems of the size commonly encountered in missile flight control applications was then demonstrated on commercial off-theshelf processors.

Nonlinear and neural network-based control of a small four-rotor aerial robot

“…For that purpose, the parameters of a real quadrotor had been identified and inserted in the simulation model. The quadrotor model was implemented as given in (9). In a first simulation, we assume an initial velocityẋ = 0.8m/sec, the other two velocities are both zero.…”

“…This seems to be computationally complex, but [9] developed some real-time methods that can be implemented on an embedded micro-controller. In addition, stability of the SDRE approach was shown in [7], [8].…”

“…the angles) and one subset that describes the translation of the UAV. From (9) we obtain the first subset of differential equations, called submodel…”

“…The basic idea of the SDREapproach was developed by [6] and applied to a number of control problems also in aerospace applications, see e.g. [6], [9], but not yet to the control of a small quadrotor UAV. The approach in [1] is further improved here and extended by the suitable addition of neural networks.…”

Optimal Fixed-Interval Integrated Guidance-Control Laws for Hit-to-Kill Missiles

“…Consequently, implementation of finite-interval integrated guidance-control techniques will require the development of more sophisticated computational capability on board the missile. Recent research on fast numerical methods for solving guidance-control problems 17 can form the starting point for this research. Additional research issues that need to be addressed in future work include the assessment of the effects of target maneuvers and sensor errors on these guidance-control laws.…”