FLIGHT CONTROL SYSTEM COMPRISING A HYDRAULIC SERVO ACTUATOR

Abstract

The disclosure relates to a flight control system comprising at least one hydraulic servo actuator, wherein the servo actuator includes a two-stage electrohydraulic servo valve, wherein the servo valve comprises a pilot stage in which the control current is translated into a hydraulic control pressure, and a power stage in which a valve slide is moved in response to the control pressure in order to adjust the throughflow direction and throughflow cross-section of the valve. The disclosure furthermore relates to an aircraft comprising such a flight control system.

Claims

1. A control system of an aircraft, wherein the system includes a control unit that is configured to generate a control current in response to a control signal, and wherein the system furthermore includes a hydraulic servo actuator for translating the control current into a movement of a control surface of the aircraft, wherein the servo actuator includes a two-stage electrohydraulic servo valve, wherein the servo valve comprises a pilot stage in which the control current is translated into a hydraulic control pressure, and comprises a power stage in which a valve slide is moved in response to the control pressure in order to adjust a throughflow direction and a throughflow cross-section of the valve, wherein the control unit is arranged on the aircraft decentrally and at a distance from a central flight control computer, and that the servo valve includes an electric feedback.

2. The system according to claim 1, wherein the servo valve has no mechanical feedback.

3. The system according to claim 1, wherein the system includes a sensor for determining a position of the valve slide, which is signal-connected to the decentral control unit.

4. The system according to claim 3, wherein the sensor is a linear variable transducer (LVTD).

5. The system according to claim 3, wherein the decentral control unit is configured to generate the control current by taking account of a regulation component from the electric feedback and a pilot control component from the control signal of the central flight control computer.

6. The system according to claim 3, wherein the decentral control unit is configured to generate the control current by taking account of a regulation component from the electric feedback and from the control signal of the central flight control computer.

7. The system according to claim 3, wherein the decentral control unit and the servo actuator of the system are arranged on a wing or a tail unit of the aircraft.

8. The system according to claim 3, wherein the decentral control unit and the servo actuator of the system are comprised by a common constructional unit.

9. The system according to claim 3, wherein a plurality of servo actuators are associated to the decentral control unit and that the decentral control unit implements an electric feedback of the servo valves comprised by this plurality of servo actuators.

10. The system according to claim 1, wherein the system includes one or more pairs of functional units with a decentral control unit and one or more servo actuators associated to the same, each configured according to claim 1, wherein it is provided that the two functional units of each of the pairs are arranged at corresponding positions on the two wings of the aircraft and use their servo actuators to act on corresponding control surfaces of the two wings.

11. An aircraft comprising a flight control system according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0022] Further details of the disclosure can be taken from the exemplary embodiment described below with reference to FIG. 1.

[0023] FIG. 1 shows an exemplary regulation with the electric feedback in servo valves of aircraft control systems according to the disclosure.

DETAILED DESCRIPTION

[0024] A decentral control unit 100 of the system translates a digital control signal 101, which is received by a central flight control computer, into a control current I.sub.el. In an electromagnetic actuation 210 of the servo valve 200, the control current I.sub.el effects the generation of a moment T.sub.m that acts on a movable component 220 in order to generate a pressure difference d.sub.p in a hydraulic control circuit of the valve 200. Depending on the configuration of the servo valve 200, the component 220 for example can be a beam splitter, a baffle plate or a movable nozzle. In response to the pressure difference d.sub.p in the hydraulic control circuit, a valve slide 230 is moved in the power stage of the valve 200, whereby the throughflow cross-section of the valve and thus the working pressure in the working circuit of a servo actuator of the system is changed.

[0025] In conventional servo valves, as they are employed in prior art flight control systems, the valve slide 230 is mechanically connected to the electromagnetic actuation 210 and/or the component 220 in order to stabilize the valve 200 in connection with a mechanical feedback.

[0026] In the system of the disclosure, this mechanical feedback is replaced by an electric feedback. For this purpose, the servo valve 200 of the system of the disclosure includes a linear variable transducer 240 by means of which the slide position x.sub.ehsv can be determined. From this slide position x.sub.ehsv a regulating signal 102 is generated, which is evaluated in the decentral control unit and is taken into account when generating the control current I.sub.el.

[0027] Hence, the regulation concept of the servo valve of the disclosure comprises a regulation component (from the electric feedback) and a pilot control component (from the control signal of the central flight control computer). In connection with the regulation, the interaction of all hydraulic, mechanical and electrical forces must be taken into account. The discrete regulation is split up into a pilot control component 110 with pole specification (dynamic pre-control), which can be executed on a field-programmable gate array (FPGA), and a regulation component (P-controller) 120, which takes account of the slide position in the form of an LV(D)T signal 102 as feedback. The pilot control can utilize the mathematical model of the idealized servo valve to determine the pilot current (static pre-control).