HIGHLIGHTS of the LECTURE # 10

SUBJECT:CORRECTING.DEVICE

I. GENERAL INFORMATION

Corrective devices are intended to change the structure and parameters for the SAS to ensure the sustainability of stocks and indicators for its quality.

Corrective devices represent the dynamic links of different physical nature with specially selected transfer functions. These, devices can be included in automatic system of three main ways:

The use of a method of inclusion is determined by the convenience of technical implementation. In linear systems for adjusting devices of the same type, you can find the equivalent in its effect to the corrective device of a different type of ratios:

For Example, The

Logarithmic scales on one or both axes can be used when building any frequency characteristics. More often than not are the characteristics, called respectively the logarithmic amplitude-frequency response (LAČH) and the logarithmic phase frequency response (LFČH).

When you build a logarithmic frequency scale characteristics instead of being postponed. The units of logarithmic coordinates is a decade (Dec) and decibel (DB)

On a logarithmic scale a decade depicted by a single length, because. Therefore, the values of the logarithmic scale is uniform, and the relative frequencies-uneven

II. SYNTHESIS OF CONSECUTIVE CORRECTIVE DEVICES

Synthesis of corrective devices using logarithmic amplitude-frequency characteristics is LAČH.

Synthesis consists of five stages:

1) build LAČH the original uncorrected systems are available LAČH;

2) build the desired LAČH;

3) determining structure and parameters for the consistent adjustment device;

4) technical implementation of sequential adjustment device;

5) building the transition process the adjusted system.

Look at the essence of each stage.

1) build LAČH available. The open-loop transfer function of the system is represented in the form of transfer function of elementary links, which are determined by the frequency of pairing. The build starts with low-frequency plot or with low-frequency Asymptote, which is determined by the coefficient of the open transmission system; next are the asymptotic performance of all links of the transfer function

2) build the desired LAČH. The LAČH build on the plots based on requirements to the quality of the transition process and highly sustainable. Low frequency plot is constructed on the basis of conditions to ensure the specified accuracy of the functioning system in established modes.

For positioning systems-low-frequency plot is an Asymptote, passing through a point on the y-axis with the slope of the frequency axis – where is the coefficient of the open transmission system; procedure astatizma-loop system. Y-axis is the axis point based frequency.

Midrange area desired LAČH is based on the time of the transition process and overshoot.. To determine the point of intersection with the axis of the asymptotes of the MF band cutoff frequency – use nomogrammoj, linking the deregulation, the maximum time of the transition process and the maximum value of the frequency characteristic of real closed-loop system. This nomogram allows for the specified value and then curve and find the cutoff frequency of open system

а)

Figure 10.1, and for specified shows the sequence of definitions. For a given receive. Through the point corresponding to the value of the Asymptote is inclined to. Midrange area is limited by the condition of the stock on the module and on the stage. For this purpose use special nomogrammoj, linking the stocks on the module and on the phase (Figure 10.2). Midrange area mated with the subwoofer using a straight line under the inclination different from mid-frequency slope area. Then check the actual margin in phase to the desired LAČH on the interface.

High-frequency plot of the desired LAČH is limited to the frequency and can have any inclination. This plot did not change significantly in the transition process.

Pairing high-and mid-frequency plots of the desired LAČH is thus to get a line with a slope of more than tilt mid-frequency plot. Then check the actual phase margin at the pairing of the desired LAČH.

1) determining structure and parameters of the adjustment device is connected with the need to build LAČH serial adjustment device by graphical computation of desired LAČH available. Then use LAČH for the typical corrective elements are approximated received LAČH corrective device. The frequency of pairing, analytical relationships that link the parameters of corrective devices with frequencies of pairing, define the specific parameter values adjustment devices.

the technical realization of corrective devices consists in selecting parameter values for elements of the corrective devices in determining inclusion adjustment device, agreeing corrective devices with functional elements of the SAS

1) 1) building, a transition system is adjusted based on the transfer function of the system, adjusted according to traditional methods. On the characteristic of the transition process are determined by the parameters of quality and are compared to the specified

2) identifying significant differences you must go back to the previous steps of the synthesis

Date: 2016-01-05; view: 759