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

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.