Bank-to-turn Research Articles

Performance enhancement methods for unstable bank-to-turn (BTT) missiles with saturating actuators

In this paper, three methods are presented to enhance the performance of an unstable missile system in the presence of multiple saturating actuators. Each method involves the design of a saturation detection system, which modifies a nominal autopilot via online optimization and maintains, to the extent possible, the multivariable properties of the nominal design. To prevent saturation due to exogenous signals, disturbances and noises, in particular, an error governor is proposed. This system processes the error signals within the feedback loop and the state of the compensator, so that appropriately co-ordinated control surface deflections may be generated. Traditionally, such a system has been applied only to stable plants. In this paper, it is shown how to design such a system for unstable plants. To prevent saturation due to reference (acceleration) commands from the guidance system, a reference governor is proposed. Such a system has traditionally required access to the entire state of the plant as wel...

Graphical visualization of missile–target air‐to‐air engagements: An educational tool for designing and evaluating missile guidance and control systems

AbstractThis article describes a user‐friendly C/C++/Windows‐based program which simulates and graphically displays a Bank‐to‐Turn (BTT) missile in pursuit of an evading target. Traditionally, students and practicing engineers must conduct extensive simulations to develop insight about such a complex “system.” In this article, an educational PC graphics program which significantly expedites this process is described. The program is organized into three modules: (1) A program‐user interface provides interactive mouse‐keyboard‐driven pull‐down menus to adjust engagement parameters. (2) A simulation module generates engagement data from a system of nonlinear differential equations modeling the missile, the autopilot, various guidance laws, and target maneuvers. (3) A graphics module uses the data to update the encounter on the screen. The program can be linked with MATLAB macros for purposes of analysis. A help/instruct facility assists users with program features and concepts. Sample missile‐target engagements are presented to demonstrate the utility of the program as an educational tool and as a tool for the analysis, design, and evaluation of missile guidance and control systems. In short, the program has proven itself as a useful educational tool for students studying feedback and control systems and as an excellent vehicle for introducing students to modeling, simulation, and graphical visualization of dynamical systems.

Saturation Prevention Strategies for an Unstable Bank-To-Turn (BTT) Missile: Full Information

In this paper, two methods are presented to enhance the performance of unstable missile system in the presence of saturating actuators. Each method involves the design of a saturation detection system which modifies a nominal autopilot via on-line optimization and maintains, to the extent possible, the multivariable properties of the nominal design. Each method is applied to the problem of controlling an unstable bank-to-turn (BTT) missile.

Optimal nonlinear tracking control for btt missiles using polynomial feedback

Abstract It is well‐known that bank‐to‐turn (BTT) control offers potential improvement in missile performance. For a highly maneuverable bank‐to‐turn missile, the dynamics of the pitch, roll, and yaw axes are not only cross‐coupled but also nonlinear, especially when high roll rates are involved. However, most BTT autopilots proposed to date rely on linear methods, either the classical SISO techniques or the state‐space methods of modern control theory. These linear approaches restrict their applicability to either small or slowly varying roll rates. The unmodelled effects of severe non‐linearities inherent in missile dynamics, particularly for asymmetric air‐frames, still remain one of the most critical issues in BTT autopilot design. In this paper, an optimal nonlinear tracking control using polynomial feedback is developed for BTT autopilots. Numerical simulations based on a 6 DOF nonlinear missile model are presented to demonstrate the effectiveness of the proposed nonlinear control technique.

Fixed-wing-angle BTT control

Optimal control theory is used to design three controllers for a fixed-wing-angle bank-to-turn (BTT) missile in a CLOS guidance system. An optimal control law which minimises integral squared error produces unacceptably high demands in roll rate. Overall economy in roll action may be achieved by inclusion of a penalty on roll rate in the cost. The third design, based on two bang-bang compensators, is closed-loop and produces a novel roll action. Simulation results demonstrate the merits of the different designs.

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.