Annotation: The article gives the analysis results for the servo drives dynamics, obtained from the theoretical calculations and during the development testing of the high power electric drives. Theoretical research was conducted, using the complete mathematical model of the servo drive, which included the equations of the control signal shaping path, electric motor, reducer and load. The equations of the control signal shaping network include only the characteristics of the compensating element in the assumption that all other delays in the transformation path are minimized. The electric motor equations are assumed in the classical form, taking into account the influence of the following main parameters on the motor dynamics: inductance and stator winding resistance, torque and armature reaction coefficients and rotor moment of inertia. Interaction of the motor with the multimass system of the reducer and load is presented in the form of force interaction of two masses – a reduced mass of the rotor and mass of the load through the certain equivalent rigidity of the kinematic chain. To describe the effect of gap in the kinematic connection the special computational trick, which considerably simplifies its mathematical description, is used. Efficiency of the reducer is presented in the form of the internal friction, proportional to the transmitted force. Calculation results with the application of the given mathematical model match well with the results of the full-scale testing of different specimens of servo drives, which makes it possible to use it for the development of new servomechanisms, as well as for the correct flight simulation when testing the aircraft control systems. In particular, based on the frequency response calculations of the closed circuit with the application of the given mathematical model, it is possible to define optimal parameters of the correcting circuit. Reaction on the step action with the various values of circular amplification coefficient in the circuit gives complete information on the stability regions of the closed circuit and influence of various drive parameters on these regions. Based on the conducted theoretical and experimental studies, the basic conclusions and recommendations were obtained and presented, accounting and implementation of which will provide high dynamic characteristics of the newly designed servo drives.

Annotation: The use of servo drives on flying vehicles determines the requirements to their dynamic characteristics. The problems of dynamics of drive with jet motor are not practically covered in publications. The task arises of selection of structure and parameters of devices consisting of several subsystems whose dynamic characteristics must be brought into agreement with each other in optimal way. The purpose of this work is to develop mathematical dependences for calculation of dynamic characteristics. The functional arrangement of the drive is considered consisting of jet motor based on Segner wheel with de Laval nozzle, mechanical transmission, pneumatic distributing device – jet pipe controlled by electromechanical converter. The layout is presented of mechanical segment of servo drive with jet motor with screw-nut transmission. The dynamic model is presented and the algebraic relations to determine natural frequencies of the drive are given. The motion equations of output rod at full composition of load are given. Using Lagrange transformation as applied to ball screw transmission, the expression for reduced mass of output element was derived. The reduced mass of load depends on the jet motor design and exerts basic influence on the drive’s natural frequencies. The evaluation is given of reduced mass change from the jet motor moment of inertia and reducer transmission coefficient. Based on the proposed algorithms, the dynamic characteristics of servo drive were constructed: transient process and amplitude-frequency characteristic. The drive has relatively low pass band, which is explained by the value of reduced mass of load.

Annotation: The general information on gas pressure reducers, on their purpose in launch vehicles and spacecraft pneumohydraulic systems is set forth. The impact of different operating conditions on physical characteristics of these devices is considered. The main and auxiliary parametric characteristics of the reducer are presented and the physical process of gas pressure reduction in it is explained. The error of output pressure regulation is evaluated using full differential of function, whose arguments (input pressure, flow rate, temperature) have scatter. The reducer temperature curve is shown and the impact of structural temperature on the value of dynamic (with flow rate) and static (without flow rate) pressure in reducer output cavity is explained. The difference between the excess pressure reducer and absolute pressure reducer is shown. The brief review of the designs of liquid and bimetal thermal compensators is presented, their advantages and disadvantages are described and the experience of reducers testing with regulating springs made of elinvar is analyzed. Attention is focused on operating temperature and its impact on stability of reducer adjustment. The formulas that describe thermodynamic processes occurring in the reducer are presented. Special attention is given to the properties of regulating spring of the reducer because of change of elasticity modulus coefficient at different temperatures, the expected pressure scatter at reducer output is evaluated and the necessity of measures to reduce this error is explained. To compensate for temperature disturbance, the formula of gas pressure in closed volume of sensitive element is derived. The essence of original technique of pneumocorrection of initial pressure in sensitive element cavity that was proposed and introduced on Yuzhnoye SDO-developed reducers is set forth.