Servo-control devices, in particular for an aircraft flight control actuator

• US 6,693,399 B2
• Filed: 06/18/2001
• Issued: 02/17/2004
• Est. Priority Date: 06/19/2000
• Status: Expired due to Term

• Current Assignee: Goodrich Control Systems (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Trw Systemes Aeronautiques Civils
• Inventors: Silvestro, Genevieve
• Primary Examiner(s): Ro; Bentsu
• Application Number:
  US09/884,176
• Publication Number:
  US 20020038841A1
• Time in Patent Office: 974 Days
• Field of Search: 318/566,584,585,586,621,632,646,615
• US Class Current: 318/566
• CPC Class Codes: G05B 19/19 characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
• CPC Class Codes: G05D 1/0825 using mathematical models
• CPC Class Codes: G05D 15/01 characterised by the use of electric means

Abstract

The invention relates to a servo-control device comprising at least one servo-control loop which receives a servo-control signal as input and whose output acts on an element to be servo-controlled, said device comprising means for determining a parameter characterizing the real force generated by the servo-control, the device also including a loop having means for determining an error characteristic of the difference between said parameter characterizing the real force and a parameter characterizing an acceptable theoretical force which is a function of the servo-control signal, and also means for correcting the processing of the servo-control loop as a function of said error. The means for determining the error make use of a reference model which is advantageously a transfer function relating force to a flow rate control signal.

Claims

1. A servo-control device comprising:

at least a first servo-control loop which receives a servo-control signal as input and whose output acts on an element to be servo-controlled;

means for determining a parameter measuring the real force generated by the servo-control;

another loop having means for determining an error which is the difference between said parameter measuring the real force and a parameter estimating an acceptable theoretical force which is a function of the servo-control signal; and

means for correcting the processing of the servo-control loop as a function of said error;

wherein the means for determining the error comprise determination means for determining a parameter estimating the acceptable theoretical force on the basis of a reference model, the determination means comprising means for implementing a transfer function having the same appearance as a transfer function or determining the parameter measuring the real force, except in the vicinity of at least one resonant frequency of said force.

2. A device according to claim 1, wherein an actuator controlled by the first servo-control loop is hydraulic and the reference model is a force/signal transfer function for controlling flow rate.

3. A device according to claim 2, wherein the determination means comprise means for implementing a transfer function having the same appearance as a transfer function for determining the parameter measuring the real force, except in the vicinity of at least one resonant frequency of said force, and wherein said transfer function is:

$\frac{F_{\mathrm{ref}}}{Q_{\mathrm{ref}}}=\frac{\mathrm{ks}}{{\left(\frac{1}{2<br><br>\mathrm{\pi <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>f_0}\right)}^2<br><br>s^2+2<br><br>x<br><br>\frac{\mathrm{<br><br>}}{2<br><br>\mathrm{\pi <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>f_0}<br><br>s+1}·<br><br>B<br><br>\left(s\right)$

where s represents the Laplacian, and where f₀ is equal to or close to a resonant frequency, x being an attenuation factor having magnitude of about 0.7 to 1, k being a gain factor, B(s) being a filter function.

4. A device according to claim 3, wherein the function B(s) is equal to 1.

5. A position servo-control device, constituted by a device according to claim 1.

6. A force servo-control device, constituted by a device according to claim 1.

7. A hydraulic servo-control device, constituted by the device according to claim 1.

8. A servo-control device for actuating a flight control or a test actuator, the device being constituted by a device according to claim 1.