No abstract

The impact point dispersion of mortar missiles can be drastically reduced with a control ring of lateral pulse jets located around the centre of gravity and a homing head to measure or to derive estimates of appropriate missile-target states, e.g. the line-of-sight rates. A simulation model including a missile as a six-degree-of-freedom vehicle, a jet pulse flight control system, and a relative missile-to-target motion was used for the comparison of four guidance laws i.e. proportional navigation guidance, augmented proportional navigation, augmented proportional navigation with rendezvous, and adaptive sliding-mode guidance. This paper focuses on the efficiency of pulse jet control on miss distance, and thus makes the assumption that sensor measurements and the guidance states required to apply each of the guidance laws are perfectly known. Proportional navigation and the adaptive sliding mode guidance exhibit a large miss distance due to limited control authority. Augmented proportional navigation is slightly better than augmented propor-

No abstract

Artillery rockets are sensitive to disturbances (total impulse variation, wind, thrust misalignment, etc.). As the range of ground-to-ground rockets increases, the accuracy of free flight rockets decreases. Requirements for the increase of the range and minimisation of the impact point dispersions can be solved by adding guidance and control systems to rockets. Based on the differences between the measured flight parameters and the calculated parameters for the nominal trajectory, the flight path angle correction algorithm is obtained by adding the correction to the nominal value. The flight path steering guidance system with lateral acceleration autopilot in the inner loop, is used for the guidance of hypothetical artillery rockets. The guidance algorithm given in this paper eliminates the time correction due to rocket velocity variations. Efficiency of the proposed algorithm is illustrated by numerical simulation. There is no practical influence of the external disturbances on impact point dispersion. It is also shown that the measurement errors of the inertial measurement unit are the dominant factor affecting impact point dispersion of artillery rockets modified by adding a guidance system based on the flight path steering method.

The excessive roll of air-launched missiles is a result of disturbances during the flight due to airframe misalignment, asymmetric control in pitch and yaw planes, atmospheric disturbances or large torque disturbances in the vicinity of aircraft. In order to overcome the undesired roll motion effects, most missiles are equipped with the roll autopilots to stabilize their roll attitude in spite of disturbances. In this paper, the classical and optimal control theory are applied in the design of a roll autopilot of the missiles controlled by the aerodynamic interceptors with the roll rate feedback in the inner loop and the roll angle in the outer loop. The desired command is transformed to the aerodynamic interceptor deflection by the pulse width modulation. The efficiency of the roll autopilot is verified on a wind tunnel model mounted on a free rotating adapter which enables movements around the longitudinal axis of the model support system. Based on the wind tunnel model response to the interceptor command, the transfer function of the wind tunnel model is determined. The results of the experiments show the influence of the roll autopilot gains on the wind tunnel model response. The wind tunnel experiments have also shown that missile oscillations occur due to the pulse width modulated deflection of the aerodynamic interceptors.