REDUCED OBSERVER IN STABILIZING SYSTEM OF A ROCKET MOTION

Abstract

Context. The peculiarity of the rocket movement as an object of control in that in the course of flight its parameters, depending of the trajectory point and fuel consumption, change significantly. It belongs also to disturbance forces that can't be directly measured by the system of sensor. Accordingly, requirements are set for the stabilization of movement, in particular, for the choice of the control law and power of actuator, which due to incomplete information about the disturbances is assigned based on estimates of their maximum values, which causes a reduction in the payload of the rocket. The need to observe the kinematic characteristics of the actuator in process of disturbances compensation is due to the necessity to determine the actual level of its loading in order to justify the design indicators and increasing requirements for the efficiency of algorithms for choosing of the control law. Objective. Development the structure chart of observer of the equivalent steering angle and its angular velocity which are directly not measured but are included in the state vector of the control object - the perturbed motion of the rocket in one of the stabilization planes. Method. A linear model of the plane motion of a space rocket, stationary in the vicinity of a certain point of the trajectory, was adopted taking into account the inertia of the stabilizing system actuator in the form of six first order linear differential equations. Available for real-time measurement are four coordinates of the control object, these are deviation of the rocket center of mass from the program position, the rotation angle of the rocket body and their derivatives in time. By representing the matrix included in the model of the control object - the perturbed movement of the body in the yawing plane, in the form of blocks, differential equations of the reduced observing device of the kinematic parameters of the actuator are obtained, there are the equivalent steering angle and its angular velocity. On the basis of these equations two variants of the structure chart have been developed, which include an integrator and linear blocs of matrix multiplication. Results. A structure chart of a reduced observing device for the angle of rotation of the steering gear of the actuator and its angular velocity during the compensation of disturbing forces for cases of use and non-use of these data in the control law is developed. Conclusions. The obtained on the basis of the measure data current values of the kinematic characteristics of the actuator can be used to determine the level of its actual download and, if necessary, to form a control law that takes into account all the coordinates of the state vector of the adopted model.