The influence of external disturbances on the control loop height

Altitude deviation from its set value may be caused by altimeter or SGC, action, disturbing moment, dumping cargo or vertical wind.

Consider the work of ACS, the management, in contact with the aircraft in a steady upward flow. After the cessation of small movements caused by an increase in the angle of attack, the aircraft gets wind speed and begins to deviate from the desired height. Of the altimeter go signal proportional to the height deviation from set point. This leads to a rejection of the elevator, the emergence of diving moment, the negative growth of the angle of attack and pitch angle. But when you change the pitch angle signal is proportional to the angle of pitch, opposite in sign to signal, proportional to the mismatch. As a result, the elevator deflection is reduced. When the signals cancel each other out, the elevator will return to the starting position. Thus, we have

,

whence

.

But the flight at a constant altitude is only possible when the longitudinal axis of the aircraft will be tilted down at an angle . Consequently, the static error in maintaining altitude determined by the expression

.

Note that the static height-keeping error in the volatile atmosphere in the presence of a signal in the pitch control law will be the case with any type of feedback, not just hard. This is explained by the fact that the signal change in altitude is always compensated signal changes of height, and set the position of the elevator does not depend on a steady wind.

Under the action of disturbing moment ACS with JOS does not maintain a specified pitch. Therefore, if any of the control law aircraft will depart from a given height. With speed and PID feedbacks aircraft to keep its current height and the action constant disturbing moment. In addition, a disturbing moment ASTATISM can ensure that the control law of the integral of height-keeping errors.

4.Automatic control of the airplane during landing
4.1. Means of providing landing

Currently, the most widely used radio system tasks approach path type SP-50 (ILS), PRMG-4, etc. In these systems, the approach path is the line of intersection of the planes of the course and glide path to reduce generated foreign exchange (MRC) and the glide path (RM), beacons, respectively. This line represents the beam. Deviation of the aircraft from the board of the beam are determined by foreign exchange (PKK), and the glide path (HF) radios.

Thus, to a range of special equipment to ensure planting include:
• ground track, glide slope and localizer RM;
• ground marker, joined at the location on the far (DPRS) and near (BPRS) NDB. Marker used to indicate the time of their flight;
• board of course and glide slope receivers PKK fracturing;
• on-board information systems: low-altitude radar altimeter, compass system, the attitude indicator, automatic control system and the system of director of management.

CRM and SRM give signals proportional to the angular deviation of the aircraft from equisignal zones in the polar coordinate system with the poles, combined with the location of the corresponding beacon. ACS based on the statistics and realized it carries stabilizing control laws of the aircraft relative equisignal zones CRM and SRM.

The layout of ground system SP-50 is shown in Fig.

Functional diagram avionics instrument landing system is shown in Fig. Crucial role in the management of computer plays trajectory control (WTU), forming setpoint signal pitch and roll angles (overloading), depending on the angular deviation of the aircraft from equisignal zones and .