CN103984353A

CN103984353A - Lateral track motion estimation and compensation method based on motion platform

Info

Publication number: CN103984353A
Application number: CN201410181873.7A
Authority: CN
Inventors: 周大鹏; 桂敬玲; 张扬; 王家兴
Original assignee: Shenyang Aircraft Design and Research Institute Aviation Industry of China AVIC
Current assignee: Shenyang Aircraft Design and Research Institute Aviation Industry of China AVIC
Priority date: 2014-04-27
Filing date: 2014-04-27
Publication date: 2014-08-13

Abstract

The invention discloses a lateral track motion estimation and compensation method based on a motion platform, and belongs to the technical field of control law design. In order to guarantee the fact that an airplane can track an ideal landing point synchronously, a guidance system must be compensated synchronously. The method aims to the last stage of a motion platform landing stage, the influences of sailing motions and swaying motions of the motion platform on ideal landing point positions are taken into comprehensive consideration, and estimation and compensation of track motions on the motion platform are carried out. Deck lateral motion signals are introduced into a lateral guidance system after estimation and compensation so that the dynamic performance of the system can be improved, errors are restrained, and the tracking precision of the airplane is improved.

Description

Lateral runway motion estimation and compensation method based on motion platform

Technical Field

The invention discloses a runway lateral motion estimation and compensation method based on a motion platform, and belongs to the technical field of control law design.

Background

Compared with the landing condition of a general airplane, the landing environment of the airplane based on the moving platform is worse, which is mainly reflected in that the change of an ideal landing point is caused by the deck movement caused by the complex airflow disturbance and the sea wave existing at the tail part, and the change brings great adverse effects on the landing precision and the safety. For example, a sudden deck lift may cause the aircraft to prematurely strike the deck or even strike the aft of the mobile platform; or the deck is suddenly lowered, so that the aircraft landing hook can not be hung on the arresting cable and is forced to carry out deck escape and fly back. Therefore, it is necessary to introduce a Deck Motion Compensator (DMC) in the landing guidance system to compensate for the changes in landing site position caused by deck motion. When the full-automatic landing system based on the motion platform is used, runway motion compensation needs to be started 12-13 seconds before the airplane is meshed with a runway on the motion platform.

Surging, swaying, rolling, and yawing in the rocking motion of a moving platform can all result in lateral motion at an ideal landing point. In addition, the included angle between the navigation motion direction of the motion platform and the central line of the oblique angle deck of the motion platformBut also on the lateral movement of the ideal landing site. Therefore, the motion of the moving platform must be compensated for so that the glided aircraft can accurately track the ideal glidepath and eliminate the aircraft lateral landing deviation caused by the motion of the moving platform. The four swaying motions and sailing motions of the motion platform are main consideration factors in the design process of the transverse-heading deck motion compensator.

On the other hand, when the radar on the moving platform measures the lateral parameters of the airplane, the origin of the reference system is fixedly connected with an ideal landing point; the x axis and the central line of the oblique angle deck are in the same direction and horizontally point to the front of the motion platform; the xy plane is a measuring reference plane and is always kept horizontal. Therefore, when the moving platform makes sailing movement and swaying movement (mainly yawing), the lateral heading parameters of the airplane measured by the radar contain errors caused by misalignment of a radar reference system and a deck shaft of the moving platform, and the radar measurement result with steady-state errors can also cause lateral landing deviation of the airplane.

Lateral landing deviations caused by the motion of the two motion platforms can be eliminated by the lateral heading DMC.

Disclosure of Invention

The method aims at:

the runway motion forecasting and compensating technology aims to eliminate phase lag by adopting the runway motion forecasting technology, compensate runway forecast information to a full-automatic landing system of an airplane based on a motion platform, effectively inhibit overshoot and eliminate delay, realize accurate tracking of deck motion by the airplane, and improve the landing accuracy and safety of the airplane.

The technical scheme of the invention is as follows:

a lateral runway motion estimation and compensation method based on a motion platform is characterized by comprising the following steps:

first, motion definition of a motion platform

The landing environment of an aircraft is a moving platform deck in motion, which is a main characteristic of the aircraft different from a land-based aircraft. The motion of the motion platform comprises two parts: one part is that it travels along a course which forms an angle with the centerline of the oblique deckThe other part is the shaking motion of the motion platform caused by wave disturbance, which comprises three translations of heaving (also known as heave), surging and rolling, and three rotations of yawing, surging and pitching, and the six motions are defined as shown in fig. 1.

Second, deck motion compensation architecture design.

Lateral landing deviations caused by motion of the moving platform can be eliminated by the lateral heading DMC, and the structure of such deck motion compensation is shown in fig. 2. In figure 2, DMC adds the measurement error of the aircraft lateral course parameter brought by the navigation and oscillation of the motion platform to the aircraft lateral position deviation signal through a deck motion compensator I, and eliminates the radar reference system and the motion platform deck shaftErrors due to misalignment; meanwhile, the two types of motion platform motion are subjected to phase lead through a deck motion compensator II, and the obtained prediction signal is converted into a rolling angle compensation signal delta phi_cAnd controlling the airplane to reduce the lateral deviation.

The symbols in the figures are defined as follows:

ψ_s-the heading angle of the motion platform in the motion platform body coordinate system;

V_s-the speed of the motion platform for uniform linear navigation;

y₀-lateral deviation of the aircraft from the deck centerline of the landing at DMC start-up;

x is the longitudinal horizontal distance of the aircraft from the ideal landing point (i.e. the distance of the aircraft from the ideal landing point in the direction of the centerline of the landing deck);

the included angle exists between the navigation motion direction of the motion platform and the central line of the oblique angle deck of the motion platform.

Third, a compensator is calculated.

Deck motion compensation command:

the lateral heading DMC should still satisfy the formula:

the formula is difficult to realize in engineering, and for the DMC model shown in FIG. 3, a compensation instruction is delta phi_CThe approximate function form of (c) is as follows:

wherein psi_CLSatisfy the requirement ofThe control structure is shown in fig. 3.

In FIG. 3, #_MIs the deviation angle, x, of the body axis of the motion platform relative to the stable axis of the vessel body₀Is the longitudinal horizontal distance, V, of the aircraft from the ideal landing point when the DMC is started₀The flight speed of the aircraft at DMC start, and χ is the aircraft track yaw angle. In the structure shown in FIG. 3, the sum V₀And V_sForm the differential of xA signal, andafter multiplication, the multiplication is amplified by 2 times to form the approximation functionThe signal represents the influence of the relative movement of the aircraft and the centerline of the landing deck on the lateral flight path deviation of the aircraft. At the same time, the user can select the desired position,after passing through the integrator and removing the initial value (eliminating the steady state error), andformed by differential elementsIn which the signals are multiplied to form an approximation functionThe signal represents the influence of the deck centerline shake on the aircraft lateral track deviation caused by the yawing motion of the motion platform. The two signals are integrated and then gainForming a compensation command Δ φ_c。

It should be noted that k in the structure shown in FIG. 3 is a variable gain reflecting the lateral direction DMC to the yaw angle ψ of the motion platform_sThe tracking rate of (2). The closer the aircraft is to the motion platform, the higher the tracking and forecasting accuracy requirement on the DMC is, so that from 10 kilometers, as the aircraft is closer to the motion platform, k gradually increases from 0 and reaches 1 when the aircraft touches the ship.

The invention has the advantages that:

deck motion estimation and compensation in the aircraft landing process are necessary links for ensuring accurate and safe landing of the aircraft. Its main advantage has:

1) the lateral movement of an ideal landing point is accurately tracked in the landing process of the airplane;

2) the landing precision of the airplane is improved;

3) ensuring the safe landing of the airplane.

Description of the drawings:

FIG. 1: motion platform perturbed motion definition

FIG. 2: ACLS horizontal channel control structure chart introducing DMC

FIG. 3: horizontal course DMC instruction model structure diagram

The specific implementation mode is as follows:

example 1

A lateral deck motion estimation and compensation method for full-automatic carrier landing.

1) Firstly, a deck motion model and required deck parameters are given

Dynamic model of heading/yaw (°) of motion platform heading motion:

longitudinal motion (m) dynamic model:

x(t)＝2294-84t

wherein,is the initial phase of the function, which can be set here

Assuming that the motion platform moves linearly at a constant speed, the motion speed V_s15m/s, aircraft yaw with respect to deck centerline at DMC start-up y₀10m, offset angle of deck midline

2) Deck motion compensator I

ψ_sThe bow rocking angle of the motion platform in the ship body coordinate system;

V_s-the speed of the motion platform for uniform linear navigation;

Substituting the motion parameters and the model of the motion platform into a formula, and making k equal to 1, the obtained deck motion compensator I is as follows:

3) deck motion compensator II

Deck motion compensator II outputs roll angle command signal delta phi_cThe command signal is used for overcoming the drift of the center line of the landing area caused by the sea waves.

The roll angle command signal of the lateral deck motion compensator II is as follows:

A set of reference parameters is given here as follows:

x is a flight path deflection angle feedback signal of the airplane;

phi is a feedback signal of the aircraft roll angle;

V₀the flying speed of the airplane when the DMC is started is taken as 90 m/s;

x₀the longitudinal horizontal distance of the aircraft from an ideal landing point when DMC starts is about 1000 m;

V_sthe speed of the motion platform for uniform linear navigation is about 15 m/s;

ψ_Mthe deviation angle of the ship body axis of the motion platform relative to the stable axis of the ship body is shown;

g is gravity acceleration, and g is 10m/s²；

Starting from 10 kilometers, as the aircraft is closer to the moving platform, k gradually increases from 0 and reaches 1 when the aircraft touches the ship, and if the ideal slip angle is 4 degrees, k is 1-x/9975.

And (3) introducing the feedback signal and the airplane model parameter into a control structure block diagram 3 to obtain a roll angle command signal as the output of the deck motion compensator II.

Claims

1. A lateral runway motion estimation and compensation method based on a motion platform is characterized by comprising the following steps:

first, motion definition of a motion platform

The landing environment of the aircraft is a moving platform deck in motion, and the motion of the moving platform comprises two parts: one part is that it travels along a course which forms an angle with the centerline of the oblique deckThe other part is the shaking motion of the motion platform caused by the wave disturbance, which comprises three translations of heaving, surging and swaying, and three rotations of bow, surging and swaying;

second, deck motion compensation design

The DMC adds the measurement error of the aircraft lateral course parameter brought by the navigation and the swaying of the motion platform to the aircraft lateral position deviation signal through a deck motion compensator I, and eliminates the error caused by the misalignment of a radar reference system and a motion platform deck shaft; meanwhile, the two types of motion platform motion are subjected to phase lead through a deck motion compensator II, and the obtained prediction signal is converted into a rolling angle compensation signal delta phi_cControlling the airplane to reduce the lateral deviation;

thirdly, calculating a compensator

Deck motion compensation command:

the lateral heading DMC satisfies the formula:

compensation instruction delta phi_CThe approximate function form of (c) is as follows:

wherein psi_CLSatisfy the requirement of