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• SIMULATION OF LIGHTNING STRIKE INDUCED CURRENTS AT MISSILERY SAMPLES TESTING

  А.А. Yakovlev, R.V. Sakhabudinov, А.S. Golosiy

  2025-01-30

  Abstract ▼

  The lightning strike (LS) to launch vehicle (LV) is accompanied by direct impact on the airframe
  and electromagnetic (EM) fields occurring inside the airframe. The EM fields influence the extended power
  lines (PL) and induce currents and voltages in them. In this case, pyrotechnic circuits of LV might be
  actuated and thus damage critically the operation of airborne equipment and the vehicle itself. Their offnominal
  ignition may lead to a catastrophe. The amplitude-time parameters of induced EM fields reach
  hundreds of kV/m and kA/m for electric and magnetic fields respectively. Constructing a simulation facility
  that is capable to produce EM fields with similar properties and size comparative to that of the LV becomes
  a tough technical challenge. The purpose of the research was to substantiate an acceptable, practically feasible method of full-scale modeling of induced currents. The research objectives were to evaluate
  the possibility of generating an electromagnetic field of specified parameters, to estimate the currents and
  voltages induced by lightning discharges in the PH cable lines, and to design a circuit solution for the
  installation under development. The electromagnetic processes occurring in cable lines when exposed to
  lightning discharge currents were calculated based on solutions to Maxwell's equations. The cable lines
  were modeled by equivalent substitution schemes. In this regard, it is considered reasonable to use a combined
  method of evaluation of LV tolerance to the impact of EM fields caused by lightning strikes; the
  method is meant to combine both calculation and experimental techniques. At the first stage, the expected
  response of extended power lines to EM fields is calculated, and the second stage implies loading the
  power line consumers with estimated current (voltage) pulses provided by high voltage test bench for
  lightning strike simulation. The use of this approach makes it possible to significantly simplify the requirements
  for test equipment for generating electromagnetic fields, which will ultimately ensure the safe
  use of pyrotechnic devices on board a launch vehicle in conditions of lightning activity.

• REVEALING THE ELECTRICAL CHARACTERISTICS OF THE DISCHARGE CIRCUIT FOR A HIGH-VOLTAGE LIGHTNING DISCHARGE STAND

  А.А. Yakovlev, М.Y. Serov, R.V. Sakhabudinov, А.S. Golosiy

  2024-08-12

  Abstract ▼

  The steady passage through the atmospheric layer by the launch vehicle where electricity discharges may
  occur is ensured not only by performance measures, but also by preliminary ground tests. The countries to be
  carrying out the launch of spacecraft into the orbit have special bench equipment. A particular system of points
  views has developed to be implemented in standards and other documents, and the given requirements have
  become obligatory to meet. The current paper is a following part of the research related to the creation of a
  high-voltage lightning discharge stand which is being developed for testing rocket and space technology products.
  The main task of this device is the generation of given electric (or electromagnetic) pulses that simulate the
  effect of lightning discharge on the structural elements of the launch vehicle. There are four pulse current generators
  in the high-voltage part such as (pulse current generator-A, pulse current generator-B, pulse current generator-
  C, pulse current generator-D-types), sequentially connected to the load to create a certain form of a
  common current pulse. Routine loads include: high-voltage grounding table, vertical rack, breakdown testing
  device. The task of this stage of work was to check the parameters of the current pulse that occurs when the
  pulse current generator-A discharges to the calibration load to be the high-voltage grounding table. The article
  illustrated the calculating findings of the pulse parameters of component A-type in the discharge circuit through
  the development of the pulse generation process: before the moment of short-circuiting of the capacitive storage
  and from the moment of short-circuiting. The discharge device such as crowbar allows you to connect the load
  according to a two-circuit circuit at the time of the maximum discharge current. Analytical dependencies of both
  equivalent electrical circuits of circuits are covered in the article. Differential equations are solved by numerical
  method, graphs of change of current and voltage of oscillatory pulse A-type in open and closed circuits are obtained.
  The given activity as well as the calculations made it possible to evaluate the dynamic characteristics of
  the studied circuit during its operation in one of the fastest flowing and energy-intensive modes of operation. In
  general, the switching of the discharge circuit to the high-voltage grounding stand with the selected parameters
  confirms the operability of the VSMR and the achievement of satisfactory characteristics of the given current
  pulse implemented by the A.-type.

• SYNTHESIS OF THE UNDERWATER CARGO LIFTING COMPLEX CONTROL SYSTEM

  P.P. Chernus, Pavel P. Chernus, А.А. Yakovlev, R.V. Sakhabudinov, А. S. Golosiy

  2024-05-28

  Abstract ▼

  A carrier vessel is used to transport an underwater cargo. The given vessel is equipped with a unit for
  lifting underwater cargoes designed to capture it, lift it, secure it on the vessel and transport it to the base
  point. The given unit includes the following components: the descent module, the lifting mechanism, the locking
  mechanism, the damping mechanism and the control system. The paper presents the findings of the mathematical
  model development of the main components for the unit to make a crucial contribution to obtaining
  reliable results – an underwater cargo, an asynchronous motor, a cable suspension and a compensation
  mechanism. The underwater cargo is described based on the theorems about the change in the amount of
  motion and kinetic moment of the mechanical system. In the equations of linear and angular displacement of
  a cargo, there is a mass of liquid in it. The cable suspension model takes into account its deformation in motion
  while operating. The model of an asynchronous motor with a short-circuited rotor is obtained from a
  generalized circuit. A vector control method is provided, the rotor flow coupling vector is taken as the base
  vector. The compensation mechanism model is based on an adiabatic process in a macroscopic system,
  where there is no heat released into. For the control system synthesis, the cargo is represented by a transfer
  function in the form of an aperiodic link of the second order. There is a three-loop PID controller synthesized
  with feedback in position, speed and current. Equations are obtained for calculating the generalized dynamic
  characteristics of a closed second-order system, and the controller parameters are calculated. The findings
  carried out on mathematical models of the system help us to obtain initial information about the linear and
  angular displacement of the descent module in steady state, the movement of points of external and internal
  suspensions, the magnitude of the force on the cables, the torque and speed developed by electric motors of
  winches. Modeling of descent, stabilization and ascent modes made it possible to adjust the parameters of the
  equipment and achieve satisfactory results of the complex's operation.

• JUSTIFICATION FOR IMAGE OF EQUIPMENT FOR UNDERWATER CARGOES

  P.P. Chernus, P.P. Chernus, А. А. Yakovlev, R.V. Sakhabudinov, А. S. Golosiy

  2024-04-15

  Abstract ▼

  The purpose of the study is to develop a method of interaction of a vessel with underwater
  cargo for both loading and transporting. The article presents the findings of the research on reacting
  a unit for lifting underwater cargo onto a vessel. The image of the unit was formed on the basis
  of an assessment of possible technical solutions, theoretical findings and modelling. The analysis
  of the previous research on creating alternatives is being carried out in the given research. To
  dock with underwater cargo from the vessel, a special receiving module is lowered at four suspension
  supports, a cable suspension scheme is of great preference. Four mechanisms have been developed
  to form the basis of the unit such as the lifting mechanism, the compensation mechanism,
  the damping mechanism and the locking mechanism. The lifting mechanism is based on electric
  winches on electric asynchronous motors worked on vector control. The rope of the lifting mechanism
  is bound through the pulley to the load. To compensate for the disturbances caused by the
  rolling of the carrier vessel, a hydropneumatic system is included in the rupture of the cable line,
  which fends off the emerging dynamic loads by moving the rods of the hydraulic cylinders. The
  damping mechanism absorbs the energy of the impact of the platform of the descent module with
  the hull of the vessel in the mooring mode. The locking mechanism ensures reliable fastening of
  the descent module with or without underwater cargo in a stowed position with the hull of the
  carrier vessel. The model of an asynchronous motor with a short-circuited rotor is obtained from a
  generalized circuit by shorting the rotor windings. A frequency control method is provided, the
  rotor flow coupling vector is taken as the base vector. The cable suspension model takes into account
  its deformation during movement during operation. The compensation mechanism model is
  based on an adiabatic process in a macroscopic system, in which the system does not release any
  heat to room. While calculating and modeling, the parameters of the nodes and mechanisms are
  selected in such a way that technically feasible conditions for the operation of the unit are provided.
  The loads on the cable system are limited and its sagging is excluded, the stroke of the compensator
  carriage is minimized. As a result, a quasi-uniform lifting of the underwater cargo was
  obtained with minor speed fluctuations during the rolling of the carrier vessel.

• SYNTHESIS OF A DIGITAL REGULATOR OF A HYDRAULIC SYSTEM FOR STABILIZING AN UNDERWATER OBJECT

  P.P. Chernus, Pavel P. Chernus , А.A. Yakovlev, R.V. Sakhabudinov, А.S. Golosiy

  2023-04-10

  Abstract ▼

  The article presents the results of the development and synthesis of a hydraulic system for
  stabilizing an underwater object. For completeness and accuracy of mathematical modeling in the
  hydraulic system, the forces of dry friction between the piston and the walls of the hydraulic cylinder,
  the forces of dry friction between the rod and the hydraulic cylinder, which together determine
  the total dry friction force in the active hydraulic cylinder, the total dry friction force in the
  passive hydraulic cylinder, and the acceleration of movement, are taken into account. Also taken
  into account is the reduced mass of the system of blocks and chain hoist, the mass of the moving
  parts of the active and passive hydraulic cylinders. After calculating the mass and dynamic characteristics
  of the hydraulic stabilization system, mathematical modeling of the developed system
  was carried out. In the process of developing and synthesizing the system, the features and typical
  non-linearities of the hydraulic and pneumatic parts included in the system were taken into account,
  such as the flow characteristic of a spool-type hydraulic valve, low leakage and compression
  costs in the working cavities of the active hydraulic cylinder. When designing, the adiabatic
  nature of the process in the pneumohydraulic displacer was adopted, since the reaction and
  movement of the hydraulic stabilization system occurs quite quickly, which means that the heat
  exchange with the environment will be negligible. In the process of synthesizing the mathematical
  model of the system, the nonlinearity of the rope elasticity coefficient is taken into account. A study
  of the stability of the mathematical model of the stabilization system was carried out and a synthesis
  of the control system for the hydraulic part of the system was carried out using a fairly common
  PID controller. The PID controller parameters were calculated using a standard calculation
  method. Since the result of the operation of the stabilization system with such a synthesis of the
  control system strongly depended on the perturbation signal, it was decided to increase the invariance
  of the system with respect to the input signal by introducing a combined control. Such an
  improvement of the system turned out to be sufficient to improve the quality of the mathematical
  model of the hydraulic stabilization system. A digital redesign of the controller was carried out,
  the features of the operation of analog-to-digital transducers of sensors were taken into account.
  The simulation results showed the operability of such a control system.