CN103593564B - Method for identifying thrust of dynamic positioning vessel - Google Patents

Abstract

The invention relates to a method for identifying thrust of a dynamic positioning vessel, and belongs to the technical field of dynamic positioning. The method for identifying the thrust of the dynamic positioning vessel comprises the following steps of (1) identifying thrust coefficients of main propellers, wherein the same pitch percentage is set for the two main propellers, and the surging position and a speed value of the dynamic positioning vessel are recorded; (2) identifying resistance coefficients of rudders, wherein the same positive pitch percentage is set for the two main propellers, opposite rudder angles are set for the two rudders, and the surging position and a speed value of the dynamic positioning vessel are recorded; (3) identifying lift coefficients of the rudders, wherein the positive pitch percentage is set for the left main propeller, a rudder angle is set for the left rudder, a negative pitch percentage is set for the right main propeller, a zero-degree rudder angle is set for the right rudder, and the heading and the turning rate of the dynamic positioning vessel are recorded; (4) identifying thrust coefficients of a side propeller, wherein a pitch percentage instruction is set for the side propeller, and the heading and the turning rate of the dynamic positioning vessel are recorded. According to the method for identifying the thrust of the dynamic positioning vessel, due to the fact that a batch identification method is adopted, parameters of identification are simplified, accuracy of parameter identification is improved, and the method for identifying the thrust of the dynamic positioning vessel has the advantages of being high in efficiency of vessel dynamic positioning, accurate in control and the like.

Description

A kind of dynamic positioning vessel thrust discrimination method

Technical field

The invention belongs to dynamically positioning technical field, particularly relate to a kind of dynamic positioning vessel thrust discrimination method.

Background technology

At present, for Large Trailing Suction Hopper Dredger, lifting pipe laying vessel, cable laying ship, the working ships such as towing/anchor handling/supply vessel, requisite back-up system when dynamic positioning system has become its operation, this system can detect the deviation between the physical location of boats and ships or platform and target location incessantly by direction reference system and sensor, again according to the wind in the external world, wave, the impact of the disturbing forces such as stream, calculate orientation and size that send as an envoy to boats and ships or platform return to target location required thrust, and thrust distribution is carried out to thruster each on boats and ships or platform, each thruster is made to produce corresponding thrust, thus on the position making boats and ships or platform remain on setting or track.The thruster of dynamic positioning vessel is generally made up of main thruster, rudder, thruster, how to obtain the key that propeller thrust is dynamic positioning system accurately.The traditional method of propeller thrust is obtained by the method for model test or theory calculate, because the difficulty of model test and error and actual value have certain difference, the result obtained by theory calculate has difference with actual conditions again, theory calculate particularly for flap-type rudder lacks effective method, cause the control of dynamic positioning of vessels accurate not, so need effective method to carry out identification to dynamic positioning vessel thrust.

Existing dynamic positioning of vessels propeller thrust discrimination method, as China Patent Publication No. CN102455708A describes the ship model on-line identification of dynamic positioning of vessels and control system and method, this ship model identification is based on kinetic effect, on-line Identifier, in ship's fix process, constantly passes through each ship parameter of Unscented Kalman Filter device Ship ' model.But this ship model needs on-line identification 34 parameters, have that to calculate complicated and real-time strong, and the technical matterss such as identification are not carried out to the lift of flap-type rudder and resistance.

Summary of the invention

The present invention provides a kind of dynamic positioning vessel thrust discrimination method for solving in known technology the technical matters that exists.

The object of this invention is to provide a kind of method adopting identification in batches, simplify the parameter of identification, improve the degree of accuracy of parameter identification, for dynamic positioning of vessels provide efficiently, the dynamic positioning vessel thrust discrimination method of the feature such as control accurately.

The surging of decoupling zero boats and ships of the present invention, swaying and yawing campaign, adopt EKF method to carry out identification to dynamic positioning vessel propeller thrust, is of the present inventionly achieved in that

The thrust model of adjustable pitch propeller is:

T=K|p-p ₀|(p-p ₀)，

K=diag{K ₁?K ₂?K ₃}

Wherein: T is the thrust of adjustable pitch propeller, p is the pitch number percent of adjustable pitch propeller, p ₀for zero pitch of adjustable pitch propeller, now thrust are zero, K ₁, K ₂for main thruster thrust coefficient, K ₃for the thrust coefficient of thruster;

The lift of rudder and resistance model are:

$L=\left\{\begin{array}{cc}K|p-p_0|(p-p_0)\left(k_{\mathrm{L\&delta;}}\right|\mathrm{\&delta;}\left|\mathrm{\&delta;}\right),& p\&GreaterEqual;0,\\ 0,& p<0,\end{array}\right.$

$D=\left\{\begin{array}{cc}K|p-p_0|(p-p_0)\left(k_{\mathrm{D\&delta;}}\right|\mathrm{\&delta;}\left|\mathrm{\&delta;}\right),& p\&GreaterEqual;0,\\ 0& p<0,\end{array}\right.$

Wherein: L is the lift of rudder, k _{l δ}for the lift coefficient of rudder, D is the resistance of rudder, k _{d δ}for the resistance coefficient of rudder, δ is rudder angle;

Promote mainly/rudder is respectively in the thrust in surging and swaying direction

$\left[\begin{array}{c}{T}_X\\ T_Y\end{array}\right]=\left[\begin{array}{c}T-D\\ L\end{array}\right]$

T _xfor promoting mainly/rudder surge direction thrust, T _yfor promoting mainly/rudder swaying direction thrust.

The motion model of dynamic positioning vessel is:

Surge motion model: $(m-X_{\stackrel{\&CenterDot;}{u}})\stackrel{\&CenterDot;}{u}-X_{u}u=X$

Swaying motion model: $(m-Y_{\stackrel{\&CenterDot;}{v}})\stackrel{\&CenterDot;}{v}-Y_{v}v=Y$

Yawing motion model: $(I_z-N_{\stackrel{\&CenterDot;}{r}})\stackrel{\&CenterDot;}{r}-N_{r}r=M$

Wherein: m is boats and ships quality, I _zfor boats and ships moment of inertia, x is surging position under hull coordinate, and y is swaying position under hull coordinate, for stem to, u is surging speed, and v is swaying speed, and r is for turning to rate, and to be boats and ships be subject in surging X makes a concerted effort, and Y is making a concerted effort of being subject in swaying of boats and ships, and M is making a concerted effort of being subject in yawing direction of boats and ships, for surging mass coefficient, X _ufor surging linear water ratio of damping, for swaying mass coefficient, Y _vfor swaying linear water ratio of damping, for bow is to additional rotation factor of inertia, N _rfor heading line water damping coefficient.

From the motion model of dynamic positioning vessel, after marine propeller thrust is determined, the motion state of boats and ships can be drawn.By discrimination method, can obtain dynamic positioning vessel propeller thrust, the ship motion state that emulation is obtained is close to true ship motion state.In dynamic positioning vessel propeller thrust identification process, first one group of ship motion parameter in a period of time is obtained, and then utilize based on the parameter identification method determination dynamic positioning vessel propeller thrust of extended Kalman filter algorithm, make the motion state obtained by dynamic positioning vessel motion mathematical model and real shipping move state deviation minimum.

The hydrodynamic force coefficient of medium power station keeping ship of the present invention x _u, y _v, n _rthe Sesam software based on potential flow theories is adopted to calculate, m, I _z, u, x, y, v, r, p, δ, x _u, y _v, n _rfor extended Kalman filter input parameter, K ₁, K ₂, K ₃, k _{l δ}, k _{d δ}for needing the parameter of identification.

The technical scheme that dynamic positioning vessel thrust discrimination method of the present invention is taked is:

A kind of dynamic positioning vessel thrust discrimination method, is characterized in: the identification of dynamic positioning vessel thrust comprises the following steps:

Step 1: the thrust coefficient of identification main thruster

The pitch number percent that given two main thrusters are identical, does not use thruster, shipping is moved, the surge motion of a consideration ship, and the surging position of record boats and ships and velocity amplitude, pick out the thrust coefficient of main thruster;

Step 2: the resistance coefficient of identification rudder

The positive pitch number percent that given two main thrusters one are identical, the rudder angle that given two rudders are contrary, makes the lift of rudder offset, do not use thruster, shipping is moved, the surge motion of a consideration ship, the surging position of record boats and ships and velocity amplitude, pick out the resistance coefficient of rudder;

Step 3: the lift coefficient of identification rudder

Given left main thruster positive pitch number percent, left rudder one rudder angle, right main thruster bear pitch number percent, right standard rudder zero rudder angle, make boats and ships surging to make a concerted effort be zero, do not use thruster, shipping is moved, consideration ship turn bow motion, record boats and ships bow to turn to rate, pick out the lift coefficient of rudder;

Step 4: the thrust coefficient of identification thruster

The instruction of given thruster pitch number percent, makes shipping move, a consideration ship turn bow motion, record boats and ships bow to turn to rate, pick out thruster thrust coefficient.

Dynamic positioning vessel thrust discrimination method of the present invention can also adopt following technical scheme:

Described dynamic positioning vessel thrust discrimination method, is characterized in: during the thrust coefficient of the lift coefficient of the thrust coefficient of identification main thruster, the resistance coefficient of identification rudder, identification rudder and identification thruster, the time making shipping dynamic is 90-150 second.

Described dynamic positioning vessel thrust discrimination method, be characterized in: during the thrust coefficient of identification main thruster, main thruster thrust coefficient corresponding during identification main thruster 25%, 50%, 75%, 100% ,-25% ,-50% ,-75% or-100% pitch number percent respectively, then thrust coefficient is fitted to the main thruster thrust thrust curve corresponding with same pitch number percent, thus thrust corresponding under obtaining any pitch number percent.

Described dynamic positioning vessel thrust discrimination method, is characterized in: during the resistance coefficient of identification rudder, given left main thruster 40-60% pitch number percent, right main thruster 40-60% pitch number percent.

Described dynamic positioning vessel thrust discrimination method, be characterized in: during the lift coefficient of identification rudder, given left main thruster 50% pitch number percent, pick out the lift coefficient that left rudder is corresponding when 10 °, 20 °, 30 °, 40 ° or 45 ° of rudder angles, then lift coefficient is fitted to the lift curve that the lift of rudder is corresponding with rudder angle, thus the lift of rudder corresponding under obtaining any rudder angle.

Described dynamic positioning vessel thrust discrimination method, be characterized in: during the thrust coefficient of identification thruster, thruster thrust coefficient corresponding during identification thruster 25%, 50%, 75%, 100% ,-25% ,-50% ,-75% or-100% pitch number percent, then thrust coefficient is fitted to the thruster thrust thrust curve corresponding with same pitch number percent, thus thrust corresponding under obtaining any pitch number percent.

The advantage that the present invention has and good effect are:

Dynamic positioning vessel thrust discrimination method is owing to have employed the brand-new technical scheme of the present invention, compared with prior art, the present invention adopts the surging of decoupling zero boats and ships, swaying and yawing motion model, adopt the method for identification in batches, simplify the parameter of identification, pick out and promoted mainly/rudder surge direction thrust and promote mainly/rudder swaying direction thrust, improve the degree of accuracy of parameter identification, efficiently, accurately control for dynamic positioning of vessels provides.

Accompanying drawing explanation

Fig. 1 is thruster configuration structure schematic diagram of the present invention;

Fig. 2 is dynamic positioning vessel thrust discrimination method schematic flow sheet of the present invention.

In figure, 1, left main thruster, 2, left rudder, 3, right main thruster, 4, right standard rudder, 5, thruster.

Embodiment

For summary of the invention of the present invention, Characteristic can be understood further, hereby exemplify following examples, and coordinate accompanying drawing to be described in detail as follows:

Accompanying drawings 1 and Fig. 2.

Embodiment 1

A kind of dynamic positioning vessel thrust discrimination method, the surging of decoupling zero boats and ships, swaying and yawing campaign, employing EKF method carries out identification to dynamic positioning vessel propeller thrust.Dynamic positioning vessel thrust identification process is as follows:

The thrust model of adjustable pitch propeller is:

T=K|p-p ₀|(p-p ₀)，

K=diag{K ₁?K ₂?K ₃}

Wherein: T is the thrust of adjustable pitch propeller, p is the pitch number percent of adjustable pitch propeller, p ₀for zero pitch of adjustable pitch propeller, now thrust are zero, K ₁, K ₂for main thruster thrust coefficient, K ₃for the thrust coefficient of thruster;

The lift of rudder and resistance model are:

$L=\left\{\begin{array}{cc}K|p-p_0|(p-p_0)\left(k_{\mathrm{L\&delta;}}\right|\mathrm{\&delta;}\left|\mathrm{\&delta;}\right),& p\&GreaterEqual;0,\\ 0,& p<0,\end{array}\right.$

$D=\left\{\begin{array}{cc}K|p-p_0|(p-p_0)\left(k_{\mathrm{D\&delta;}}\right|\mathrm{\&delta;}\left|\mathrm{\&delta;}\right),& p\&GreaterEqual;0,\\ 0& p<0,\end{array}\right.$

Wherein: L is the lift of rudder, k _{l δ}for the lift coefficient of rudder, D is the resistance of rudder, k _{d δ}for the resistance coefficient of rudder, δ is rudder angle;

Promote mainly/rudder is respectively in the thrust in surging and swaying direction

$\left[\begin{array}{c}{T}_X\\ T_Y\end{array}\right]=\left[\begin{array}{c}T-D\\ L\end{array}\right]$

T _xfor promoting mainly/rudder surge direction thrust, T _yfor promoting mainly/rudder swaying direction thrust.

The motion model of dynamic positioning vessel is:

Surge motion model: $(m-X_{\stackrel{\&CenterDot;}{u}})\stackrel{\&CenterDot;}{u}-X_{u}u=X$

Swaying motion model: $(m-Y_{\stackrel{\&CenterDot;}{v}})\stackrel{\&CenterDot;}{v}-Y_{v}v=Y$

Yawing motion model: $(I_z-N_{\stackrel{\&CenterDot;}{r}})\stackrel{\&CenterDot;}{r}-N_{r}r=M$

Wherein: m is boats and ships quality, I _zfor boats and ships moment of inertia, x is surging position under hull coordinate, and y is swaying position under hull coordinate, for stem to, u is surging speed, and v is swaying speed, and r is for turning to rate, and to be boats and ships be subject in surging X makes a concerted effort, and Y is making a concerted effort of being subject in swaying of boats and ships, and M is making a concerted effort of being subject in yawing direction of boats and ships, for surging mass coefficient, X _ufor surging linear water ratio of damping, for swaying mass coefficient, Y _vfor swaying linear water ratio of damping, for bow is to additional rotation factor of inertia, N _rfor heading line water damping coefficient.

From the motion model of dynamic positioning vessel, after marine propeller thrust is determined, the motion state of boats and ships can be drawn.By discrimination method, can obtain dynamic positioning vessel propeller thrust, the ship motion state that emulation is obtained is close to true ship motion state.In dynamic positioning vessel propeller thrust identification process, first one group of ship motion parameter in a period of time is obtained, and then utilize based on the parameter identification method determination dynamic positioning vessel propeller thrust of extended Kalman filter algorithm, make the motion state obtained by dynamic positioning vessel motion mathematical model and real shipping move state deviation minimum.

The hydrodynamic force coefficient of the present embodiment medium power station keeping ship x _u, y _v, n _rthe Sesam software based on potential flow theories is adopted to calculate, m, I _z, u, x, y, v, r, p, δ, x _u, y _v, n _rfor extended Kalman filter input parameter, K ₁, K ₂, K ₃, k _{l δ}, k _{d δ}for needing the parameter of identification.Comprise the following steps:

Step 1: the thrust of identification main thruster

The pitch number percent that given two main thrusters are identical, does not use thruster, makes shipping dynamic 120 seconds, the surge motion of a consideration ship, and the surging position of record boats and ships and velocity amplitude, pick out the thrust of main thruster.M, x _u, u, x, p, be known parameters, K ₁, K ₂for the parameter that extended Kalman filter picks out.

Step 2: the resistance of identification rudder

The positive pitch number percent that given two main thrusters one are identical, the rudder angle that given two rudders are contrary, makes the lift of rudder offset, do not use thruster, make shipping dynamic 120 seconds, the surge motion of a consideration ship, the surging position of record boats and ships and velocity amplitude, pick out the resistance of rudder.M, x _u, u, x, p, δ, K ₁, K ₂for known parameters, K ₁, K ₂for the parameter picked out in step 1, k _{d δ}for the parameter that extended Kalman filter picks out.

Step 3: the lift of identification rudder

Given left main thruster positive pitch number percent, left rudder one rudder angle, right main thruster bear pitch number percent, right standard rudder zero rudder angle, make boats and ships surging to make a concerted effort be zero, do not use thruster, make shipping dynamic 120 seconds, consideration ship turn bow motion, record boats and ships bow to turn to rate, pick out the lift of rudder.I _z, r, p, δ, N _r, K ₁, K ₂, k _{d δ}for known parameters, K ₁, K ₂for the parameter picked out in step 1, k _{d δ}for the parameter that step 2 picks out, k _{l δ}for the parameter that extended Kalman filter picks out.

Step 4: the thrust of identification thruster

The instruction of given thruster pitch number percent, makes shipping dynamic 120 seconds, a consideration ship turn bow motion, the bow of record boats and ships to turn to rate, pick out thruster thrust.I _z, r, p are known parameters, K ₃for the parameter that extended Kalman filter picks out.

Embodiment 2

A kind of dynamic positioning vessel thrust discrimination method, with reference to the thruster arrangement plan of Fig. 1 boats and ships.X-direction is the surge direction of boats and ships, and the direction pointing to stem is positive dirction; Y-direction is the swaying direction of boats and ships, and the direction pointing to boats and ships right strings is positive dirction, M direction be the bow of boats and ships to direction, stem points to X positive dirction be zero bow to, rotate in a clockwise direction; The thruster of this ship is configured to: left main thruster 1, left rudder 2, right main thruster 3, right standard rudder 4, thruster 5, and left main thruster 1, right main thruster 3 are identical adjustable pitch propeller, and thruster 5 is adjustable pitch propeller; Left rudder 2, right standard rudder 4 are identical flap-type rudder.

The hydrodynamic force coefficient of boats and ships in the present embodiment x _u, y _v, n _rthe Sesam software based on potential flow theories is adopted to calculate, m, I _z, u, x, y, v, r, p, δ, x _u, y _v, n _rfor extended Kalman filter input parameter, K ₁, K ₂, K ₃, k _{l δ}, k _{d δ}for needing the parameter of identification.

Reference Fig. 2 is discrimination method process flow diagram.Dynamically positioning discrimination method step is as follows:

Step 1: the thrust of identification main thruster

Rotate stem to, ship is acted on by the wind of side direction, stream, affects the surge motion of ship as far as possible less.Given left main thruster pitch number percent p ₁, right main thruster pitch number percent p ₃, left and right main thruster pitch number percent is identical, thrust coefficient is identical, does not use thruster, makes shipping dynamic 120 seconds.M, x _u, x, u, p ₁, p ₃for known parameters, K ₁, K ₂for the parameter that extended Kalman filter picks out.The model that identification adopts is as follows:

$(m-X_{\stackrel{\&CenterDot;}{u}})\stackrel{\&CenterDot;}{u}-X_{u}u=X$

X=T=2K ₁|p-p ₀|(p-p ₀)

K ₁=K ₂

The surge motion of consideration ship, the surging position of record boats and ships and speed, pick out the thrust coefficient of main thruster.This step has test altogether 8 times, main thruster thrust coefficient corresponding during identification main thruster 25%, 50%, 75%, 100% ,-25% ,-50% ,-75% ,-100% pitch number percent respectively, then these 8 thrust coefficients are fitted to the main thruster thrust thrust curve corresponding with same pitch number percent, thus thrust corresponding under obtaining any pitch number percent.

Step 2: the resistance of identification rudder

Rotate stem to, ship is acted on by the wind of side direction, stream, makes wind as far as possible, surge motion that stream affects ship less.Given left main thruster 50% pitch number percent, right main thruster 50% pitch number percent, given left rudder δ ₂rudder angle, right standard rudder-δ ₂rudder angle, the lift size of now port and starboard generation is identical, direction contrary, do not use thruster, makes shipping dynamic 120 seconds.M, x _u, u, x, p ₁, p ₃, δ ₂, δ ₄, K ₁, K ₂for known parameters, K ₁, K ₂for the parameter picked out in step 1, k _{d δ}for the parameter that extended Kalman filter picks out.The model that identification adopts is as follows:

$(m-X_{\stackrel{\&CenterDot;}{u}})\stackrel{\&CenterDot;}{u}-X_{u}u=X$

X=2(T-D)

The surge motion of consideration ship, the surging position of record boats and ships and velocity amplitude, pick out the resistance coefficient of rudder.This step has test altogether 5 times, respectively identification rudder 10 °, 20 °, 30 °, 40 °, 45 ° of rudder angles time corresponding resistance coefficient coefficient, then the resistance curve that the resistance these 5 resistance coefficients being fitted to rudder is corresponding with rudder angle, thus the resistance of rudder corresponding under obtaining any rudder angle.

Step 3: the lift of identification rudder

Rotate stem to, ship is subject to the wind, flow or against the wind, stream acts on, make wind as far as possible, the bow that turns that stream affects ship less move.Given left main thruster 50% pitch number percent, left rudder δ ₂rudder angle, right main thruster pitch number percent p ₃, right standard rudder zero rudder angle, make boats and ships surging to make a concerted effort be zero, only do and turn bow motion, make shipping dynamic 120 seconds.I _z, r, p ₁, p ₃, δ ₂, δ ₄, N _r, K ₁, K ₂, k _{d δ}for known parameters, K ₁, K ₂for the parameter picked out in step 1, k _{d δ}for the parameter that step 2 picks out, k _{l δ}for the parameter that extended Kalman filter picks out.The model that identification adopts is as follows:

$(I_z-N_{\stackrel{\&CenterDot;}{r}})\stackrel{\&CenterDot;}{r}-N_{r}r=M$

T ₁-L ₁=-T ₃

This step has test altogether 5 times, according to the resistance coefficient promoted mainly into thrust coefficient and rudder that step 1, step 2 identification obtain, calculate left rudder 10 °, 20 °, 30 °, 40 °, 45 ° of rudder angles time corresponding p ₁and p ₃consideration ship turn bow motion, record boats and ships bow to turn to rate, pick out respectively left rudder 10 °, 20 °, 30 °, 40 °, 45 ° of rudder angles time corresponding lift coefficient, then the lift curve that the lift these 5 lift coefficients being fitted to rudder is corresponding with rudder angle, thus the lift of rudder corresponding under obtaining any rudder angle.

Step 4: the thrust of identification thruster

Rotate stem to, ship is subject to the wind, flow or against the wind, stream acts on, make wind as far as possible, the bow that turns that stream affects ship less move.Given thruster pitch number percent instruction p ₅, do not use main thruster and rudder, make shipping dynamic 120 seconds, I _z, r, p are known parameters, K ₃for the parameter that extended Kalman filter picks out.The model that identification adopts is as follows:

$(I_z-N_{\stackrel{\&CenterDot;}{r}})\stackrel{\&CenterDot;}{r}-N_{r}r=M$

Consideration ship turn bow motion, the bow of record boats and ships to turn to rate, pick out thruster thrust coefficient.This step has test altogether 8 times, thruster thrust coefficient corresponding during identification thruster 25%, 50%, 75%, 100% ,-25% ,-50% ,-75% ,-100% pitch number percent respectively, then these 8 thrust coefficients are fitted to the thruster thrust thrust curve corresponding with same pitch number percent, thus thrust corresponding under obtaining any pitch number percent.

Embodiment improves the degree of accuracy of parameter identification, have described dynamically positioning ship positionning efficient, control the good effects such as accurate.

Claims (2)

1. a dynamic positioning vessel thrust discrimination method, is characterized in that: the identification of dynamic positioning vessel thrust comprises the following steps:

(1) thrust coefficient of identification main thruster

The pitch number percent that given two main thrusters are identical, does not use thruster, shipping is moved, the surge motion of a consideration ship, and the surging position of record boats and ships and velocity amplitude, pick out the thrust coefficient of main thruster;

During the thrust coefficient of identification main thruster, main thruster thrust coefficient corresponding during identification main thruster 25%, 50%, 75%, 100% ,-25% ,-50% ,-75% and-100% pitch number percent respectively, then thrust coefficient is fitted to the main thruster thrust thrust curve corresponding with same pitch number percent, thus thrust corresponding under obtaining any pitch number percent;

(2) resistance coefficient of identification rudder

The positive pitch number percent that given two main thrusters one are identical, the rudder angle that given two rudders are contrary, makes the lift of rudder offset, do not use thruster, shipping is moved, the surge motion of a consideration ship, the surging position of record boats and ships and velocity amplitude, pick out the resistance coefficient of rudder;

During the resistance coefficient of identification rudder, given left main thruster 40-60% pitch number percent, right main thruster 40-60% pitch number percent;

(3) lift coefficient of identification rudder

Given left main thruster positive pitch number percent, left rudder one rudder angle, right main thruster bear pitch number percent, right standard rudder zero rudder angle, make boats and ships surging to make a concerted effort be zero, do not use thruster, shipping is moved, consideration ship turn bow motion, record boats and ships bow to turn to rate, pick out the lift coefficient of rudder;

During the lift coefficient of identification rudder, given left main thruster 50% pitch number percent, pick out the lift coefficient that left rudder is corresponding when 10 °, 20 °, 30 °, 40 ° and 45 ° of rudder angles, then lift coefficient is fitted to the lift curve that the lift of rudder is corresponding with rudder angle, thus the lift of rudder corresponding under obtaining any rudder angle;

(4) thrust coefficient of identification thruster

The instruction of given thruster pitch number percent, makes shipping move, a consideration ship turn bow motion, record boats and ships bow to turn to rate, pick out thruster thrust coefficient;

During the thrust coefficient of identification thruster, thruster thrust coefficient corresponding during identification thruster 25%, 50%, 75%, 100% ,-25% ,-50% ,-75% and-100% pitch number percent, then thrust coefficient is fitted to the thruster thrust thrust curve corresponding with same pitch number percent, thus thrust corresponding under obtaining any pitch number percent.

2. dynamic positioning vessel thrust discrimination method according to claim 1, it is characterized in that: during the thrust coefficient of the lift coefficient of the thrust coefficient of identification main thruster, the resistance coefficient of identification rudder, identification rudder and identification thruster, the time making shipping dynamic is 90-150 second.