Lateral Autopilot Design Research Articles

Short Range Missile Autopilot Design using Fuzzy Control Technique

Anti-tank short range missiles can be categorized in the most widely used weapons in the recent ground battle field. Development of a trusted autopilot for these kinds of missiles is a very critical issue. Although classical control techniques can provide a good and stable solution, but with time, the uncertainties increase and hence the designed classical controller (CC) is no longer valid to cope with this kind of problems. This paper represents a lateral displacement controller design of a missile model. Classical control technique shows satisfactory results in missile maneuvering while it fails to intercept the target in case of thrust degradation (aging of the missile rocket motor) and uncertainties in aerodynamics. A new lateral autopilot design for a roll stabilized skid to turn (STT) missile using fuzzy control technique is adopted and introduced in this paper. In this new controller the parameters of fuzzy logic are designed to optimize the performance characteristics of the plant. The simulation results show that the fuzzy logic control shows better performance in case of thrust degradation and uncertainties in aerodynamics.

Nonlinear Autopilot Design and Guidance-in-Loop Validation for a Tactical Air-to-Air Flight Vehicle

In this paper, design and analysis of nonlinear autopilot of a tactical flight vehicle has been carried out for surface to air application. The lateral autopilot design is based on dynamic inversion and time scale separation principle. The roll autopilot design is based on back stepping technique. At first, better tracking performance of present autopilot with respect to linear design at higher angles of attack in presence of side force and aerodynamic nonlinearity and its robustness study with respect to plant parameter variation has been carried out through six degrees of freedom simulation. Later, successful tracking performance of the pursuer nonlinear autopilot while tracking guidance command has also been demonstrated through realistic six degrees of freedom simulation of a pursuer evader engagement.

Application of velocity-based gain-scheduling to lateral auto-pilot design for an agile missile

In this paper a modern gain-scheduling methodology is proposed which exploits recently developed velocity-based techniques to resolve many of the deficiencies of classical gain-scheduling approaches (restriction to near equilibrium operation, to slow rate of variation). This is achieved while maintaining continuity with linear methods and providing an open design framework (any linear synthesis approach may be used) which supports divide and conquer design strategies. The application of velocity-based gain-scheduling techniques is demonstrated in application to a demanding, highly nonlinear, missile control design task. Scheduling on instantaneous incidence (a rapidly varying quantity) is well-known to lead to considerable difficulties with classical gain-scheduling methods. It is shown that the methods proposed here can, however, be used to successfully design an effective and robust gain-scheduled controller.

OPTIMAL FEEDFORWARD AND FEEDBACK CONTROLLERS DESIGNED BY LQG/LTR METHOD

ABSTRACT The objective of this paper is to propose both feedforward and feedback controllers designed by the Linear Quadratic Gaussian and Loop Transfer Recovery (LQG/LTR) methodology. The adoption of a two-degree-of-freedom controller with feedforward and state-feedback controllers can improve the disadvantages of high gain for only feedback controllers designed by the LQG/LTR method. This paper also derives the algorithms which can take all the time-domain, frequency-domain, and robust design techniques into a unified method. An example of F-16 lateral autopilot design is given, which shows that the proposed method is more robust to measurement noise and more practical in applications, and has better steady-state responses in time domain.

Optimal controller for homing missile

The optimal control theory is applied to the homing missile lateral autopilot design. The approach is to adapt the autopilot gains to the environment model reference and to vary as functions of time-to-go to minimize the performance index. The path constraint is applied throughout the whole terminal homing period and infinite penalty is imposed at intercept. A single-plane, linear autopilot design and implementation consideration are addressed for skid-to-turn (STT) case. Application to bank-to-turn (BTT) control is also discussed.

Optimal regulation of stochastic linear systems with adjustable parameter

The problem of optimal regulation for stochastic linear systems with adjustable plant parameters is examined and posed as a nonlinear programming problem. A computational procedure, built around the Generalized Reduced Gradient algorithm, is developed to solve the associated plant-controller design problem. The procedure is illustrated via a lateral autopilot design in which the quality of regulation is improved by approximately 18% over that achievable with a nominal fixed plant.