SU503207A1 - Method of controlling an object in systems with a relay leading element - Google Patents

Description

one

The invention relates to control systems with variable parameters and can be used in relay control systems of slowly flowing and inertial objects.

A known method of controlling an object in systems with a relay leading element consists in forming a control action in the interval from the time of the coincidence signal magnitude and the magnitude of the switching signal of the relay element to the moment of decreasing the magnitude of the decreasing error signal and the magnitude of the switching signal of the relay element. However, when using the known control method, it is impossible to choose such a loop width that would simultaneously satisfy the specified parameters of transient and established processes.

To improve the quality of the control process, it is proposed to reduce the value of the disconnecting signal of the relay element in the time interval from the moment of switching on the relay element to the moment of coincidence of the magnitude of the increasing error signal and the value of the disconnecting signal of the relay element. In addition, it is proposed to reduce the value of the trip signal of the relay element with a constantly increasing speed.

FIG. Figure 1 shows the static characteristic of the relay leading element; in fig. 2 - phase trajectories of movements in the implementation of the proposed method. FIG. 1, the abscissa shows the magnitude of the deviation of the controlled variable — the current control error φ; the ordinate axis is the amplitude of the output signal of the leading element A; fa (-f) is the magnitude of the turn-on signal of the relay element;

F (-f) is the static value of the disconnecting signal of the relay element; f. , f.

(, 2, 3, ...) are the current values of the disconnecting signal of the relay element; in fig. 2 -

the abscissa axis shows the magnitude of the deviation of the regulated value — the current control error f; the ordinate axis is the deviation rate of the controlled variable f; M - the current position of the depicting

points; (fa, -ph,, - (fb are static on and off limits, respectively, determined by static values of the on and off signals of the relay element; fb, - (f 1c-mixed off limits, determined by the current values of the off signal of the relay element. Essence control method is as follows. The boundaries of the fa and -fa define the dead zone of the control system that implements the proposed method. At these boundaries, the executive organs (IO), the point MI, are turned on and they are turned off, if they were not switched off earlier: iri movement of the imaging point in the interval f, ff or -fa, -f.

switching on the EUT, the value of the disconnecting signal of the relay element begins to shift (decrease), i.e., the boundary of the phg, (- fb), is shifted, with a constantly increasing speed. At some point, the imaging point reaches the shifted cut-off boundary of f & (point MZ) At this point, the decrease in the trip signal of the relay element stops, i.e., the fb boundary offset stops. When, in the course of its reduction, the error signal takes on a value equal to the switch-off signal of the relay element, the formation of the control action ends (point L1c).

There is an interval of initial velocities of the imaging point (for example, the speed F2), at which its encounter with the displaced off line f, occurs at a negative velocity of the imaging point (point M). There is also an interval of initial velocities of the imaging point M (for example, the speed fz), at which it never meets the shifting line of disconnection, i.e., at these speeds, the disconnection of the EUT occurs at the border of the dead zone.

If we assume that in the control system that implements the proposed method, there are no delays, then we can speak of the established movements (oscillations) near the equilibrium position with the velocity

equal to the initial one that does not provide for crossing the cut-off border of the phg, (speed fz). In real-world control systems, oscillations "are unwound until a point M meets the displaced shut-off line.

Reducing the magnitude of the disconnect signal of the relay element with increasing speed

allows to provide good damping of movements with high initial speeds and at the same time gives a good quality of established movements, which is unattainable in control systems, which include advanced elements with unchangeable shutdown levels.

Claims (2)

1. A method for controlling an object in systems with a relay leading element, which consists in forming a control action in the interval from the moment of coincidence of the magnitude of the error signal and the magnitude of the turn-on signal of the relay element to the moment of coincidence of the magnitude of the decreasing error signal and the magnitude of the disconnect signal of the relay element, characterized in that, in order to improve the quality of the control process, the magnitude of the disconnect signal of the relay element is reduced in the time interval from the moment of switching on the relay element until the coinciding magnitude of the increasing error signal and the magnitude of the disconnect signal relay element. 2. A method according to claim 1, characterized in that the value of the trip signal of the relay element decreases with a constantly increasing speed. iff Rig. g