JPH04154498A - Estimating method for control motion using controllability index - Google Patents

Abstract

PURPOSE:To carry out the simulation of some ship control motion using a personal computer loaded in a ship by utilizing data regarding the controllability of an actual ship which has been accumulated to set the index of the response model of a newly constructed ship without carrying out a model test, and estimating the control performance of the ship. CONSTITUTION:An equivalent K index is defined in such a way that a K index obtained from the stationary turning characteristic of a ship by use of the response model of the turning anglular velocity of a ship and the response model of lowering of ship speed as bases. The ratio of K, T indexes obtained respectively from the equivalent K index of existing actual ship data for each steering angle and from a Z control test is adjusted in relation to the ratio of the degree of fineness of the ship to a rudder area ratio. The relation between the equivalent K index obtained from the turning test of existing data and the K index obtained from the Z control test is found and the stationary turning angular velocity of the maximum steering angle of a newly constructed ship is estimated from the existing data and the stationary turning characteristic of the newly constructed ship is found using adjusted data. The K, T indexes for the Z control motion of the newly constructed ship are set and the response model set are finally identified while the result of a controllability test carried out at the official trial of the newly constructed ship is referred to.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for estimating the maneuvering motion of a new ship by utilizing the maneuverability index K, ■ of actual ships accumulated at each shipyard. .

[Conventional technology]

Research on the analysis of ship maneuvering motion using response models was significantly advanced by many researchers from the early 1960s to the late 1970s. A response model that can be used practically for estimating the maneuvering motion of a ship has become a reality. However, in order to more rationally determine changes in maneuverability due to hull form factors, we must return to the origins of the fluid force acting on the hull.
Since it was recognized that it would be better to assemble a mathematical model, research using hydrodynamic models became mainstream, and currently, simulations of maneuvering motion using hydrodynamic models are carried out not only in deep water but also in shallow water. Many σ research institutes are conducting simulations to verify maneuvering motion at high speeds and under the influence of external disturbances.

[Problem to be solved by the invention] In order to ensure the safety of ship navigation, the IMO (International Maritime Organization) recommends that new ships be constructed so that ship operators can fully understand the bell operation performance of their own ship. He suggested that a hooklet should be prepared for the ship. However, in order to estimate the basic maneuverability of a new ship by applying a hydrodynamic model,
The problem must be overcome that many steering derivatives for the set must be obtained by restrained model testing. The reason for this is that the data on the steering derivative has not yet been prepared, and there is still too much data to put it into practical use.Are there any theoretical estimation methods for the steering derivative that have been proposed?At present, the accuracy of the estimated value is This is because the calculations for estimating the motion of a ship in waves have not yet been calculated and put to practical use, since the current situation is still unsatisfactory. Sarak, IMO, one elephant [1, 11
It is extremely difficult for each shipyard that builds old f DWT Shell 1 ships to obtain all the maneuvering coefficients for new ships. In order to promote the preparation of ship maneuvering hooklets under such circumstances, it is desirable to establish a method that can estimate maneuvering motion with practical accuracy by utilizing existing data.

(Means for Solving the Problems) The means of the present invention for solving the above-mentioned conventional problems is based on a turning angular velocity response model and a ship speed reduction response model. The index is defined equivalently including non-linearity, and the ratio of the index of existing actual ship data for each rudder angle and the ratio of the K and T index obtained in the Z maneuver test is calculated based on the ship's degree of obesity. This is organized based on the rudder area ratio, and the ship speed reduction rate is related to the square of the turning angular velocity. Furthermore, let us find the relationship between the equivalent index obtained from the turning test using existing data and the equivalent index obtained from the Z maneuver test. First, estimate the steady turning angular velocity at the maximum rudder angle of the new ship from existing data, use the organized data to find the steady turning characteristics of the new ship, and then calculate the K and T indices for the two maneuvering movements of the new ship. It is assumed that the turning motion equivalently shifts to an index as the turning develops.

Finally, there is a method of identifying the set response model by referring to the maneuverability test results conducted during the trial run of the newly built ship.

(effect) The estimation method of the present invention will be explained below.

1-1 Concept of the proposed estimation method In order to be able to estimate the maneuvering motion of an actual ship with practical accuracy, the following concept is used based on the response model of turning angular velocity and the response model of ship speed reduction. Build an estimation method.

1) Since the correlation between actual ships and models regarding maneuverability has not been established, actual ship test data will be used, and existing data will be organized and used effectively.

2) A simple response model is adopted, and the response model of the turning angular velocity r and the response model of the change in forward speed U (vessel speed reduction amount) are combined, and Tr+r+yr' = K (δ+δ r )
(]) Tu u+u=Kt+ r2
Use (2). Tatami, K and r
is made dimensionless using the momentary ship speed U.

3) Assuming that K', T' product index varies depending on the rudder angle δ, define the index equivalent to the angle rudder angle, include nonlinearity in this, and if the T' product index rudder angle is the same, turning motion, Assume that the Z-steering motion is the same.

4) Steady turning characteristics of the actual ship, r'-6 curve, ship speed reduction rate, and ', T' obtained from turning test and Z maneuvering test
Organize the relationship of index data. The same response model is used for any given ship maneuver, and the maneuver motion is simulated by directly giving numerical data to the K'T' index.

The above idea will be explained in more detail.

I-2 Maneuverability index ', T' data As for the ship's maneuverability, can each performance of course keeping, course change, and emergency avoidance be investigated?
Test method suitable for examining each performance Since the value of the 'T' index depends on the period of motion depending on the rudder angle, two maneuver tests and a turning test performed at the same rudder angle are used. Test (reverse y<.

Even if the results are different (including the Iral test), the values of the ' and T' indexes obtained are different. This is because in the two-maneuver test, when the azimuth reaches a set value, the rudder is turned to the opposite side, and the turning angular speed at that time is different from the steady turning speed in the turning test. It is thought that such a difference will be greatly apparent in the modified Z-steering test, which is suitable for investigating the directional stability of enlarged ships.

The maneuverability of a ship differs depending on the type of ship.In general, bathing type ships have good course stability, while enlarged ships have not-so-good course stability. There are many structural factors involved in the maneuverability of a ship, including reading coefficient CB, length-width ratio L/B, and width-draft ratio B.
/d, rudder area ratio AR/Ld, etc. By analyzing the maneuverability test data of the actual ship, p is defined as K'/2T'.
The index is the ratio of the product of the ship's length and rudder area to the ship's displacement volume, LA
.

/, it is reported that it is a linear function. Referring to this idea, the value of T' index is calculated as fertilizer bath degree CB/(L,/B)
Considering that the value of Ni' index has a strong correlation with the rudder area AR/Ld, we take the ratio of CR7/ (L,, -' B ) and AR2Ld and get Δ□= (C,/ (L,,' B)) ′(AR,/
Define Ld)=/L A R (3). The ratio of the values of N′ and T′ index values obtained from the Z maneuver test, K′R/T′z, is calculated by profiling against ΔF8.
An example of this is shown in Figure 1. The values of K',/T'2 are fairly consistent depending on the type of ship, and the value of K'z/T'z becomes smaller as the value of 8FH becomes more severe.

I-3 Turning angular velocity response model coefficients (1) Value of the r' index obtained from the turning test results Figure 2 shows the typical shape of the r'-6 curve representing the steady turning characteristics of an enlarged ship. In the first-order turning angular velocity response model (1), r=0 during steady turning, so r'+ y r''=K (δ'+δ'r) (
4), and the values of the ' index and the nonlinear coefficient ν can be obtained by setting δ' = 0 (or known). However, since the values of 'index and ν differ for each steering angle, we assume that the value of K' index also changes for each steering angle, and we consider the equivalent 'index' that includes the nonlinear influence of νr3. Let this be ′, then 1・=3・E6・ (5) As shown in Figure 2, find the value of ′1 at δ=35′ of the r′-6 curve and set this as ′E: +5. , similarly, δ
= 5°, too, the value of −, at 20″ is ′Eδ
shall be. From the shape of the r'-6 curve, the value of K'E8 is approximately the same as the value of K'E3S for a ship with good course stability, but for a ship with poor course stability, the value of K'E8 is approximately the same as the value of K'E3S at the small rudder angle. The value of Ea tends to be larger than the value of K'E3S, and smaller than the value of E3g for ships with poor course stability. Find the value of K for each steering angle from the existing r-6 curve, define the ratio to K'EffS as ξ6, and ξ =
Let K ′E 5 / K ′E35 (6) δ. ξ8 with δ=5', 10', 20°
An example in which the value of is calculated and plotted against Δ is shown in FIG. The value of ξ2o is approximately l, or may be about 1.3 for eight FR or large set types. On the other hand, the value of ξ is about 1.3 even when the APR is small, and as Δ increases, the value increases to 2 to 3, and nonlinearity appears in the K' index.

The values of ξ5, ξ1o, and ξ2o for APR are quite well organized, so to find the 8FR of a newly built ship, we use the value of 'F13° or r'3. Based on the value of ξ, find the value of ξ from Figure 3.
It is possible to easily draw an r'-6 curve for δ. Figure 4 shows the value of 'l:35 as 8FH
Is it easy to estimate the value of r'+5, since the turning test data of many existing ships has been organized in terms of ship length, rudder area ratio, etc.? I'll come. The value of r' at δ=0'', that is, the approximate value of the unstable loop height 10, can be estimated by linear extrapolation from the values of r' and r'IO.

(2) The value of the T' index obtained from the Z maneuver test results. It is assumed that the value of T' index is the same for turning motion and Z steering motion if the steering angle is the same. Since the value of '6 is estimated to represent the steady turning characteristics, if we know whether it corresponds to the value of '2 obtained by two maneuver tests for the same steering angle, we can calculate the value of the T'7 index from Figure 1. It is possible to estimate. In the response model of the turning angular velocity to the turning motion, the index is assumed to be z at the beginning of the turning motion, and as the turning motion develops, it shifts to the index over time and enters a steady rudder turn. The ratio of the values of '7 and 'E at angle δ is defined as η6, and ηδ='Z/' (7)
shall be. An example in which the values of '2 and '6 were extracted from an example where a turning test and a Z maneuver test were conducted on an existing ship, and the obtained value of ηδ was plotted against Δ□ is as follows: δ=5°, 10 '
, 20° as shown in FIG.

Since there is a large variation in the value of ′z8 obtained from the analysis of the actual ship Z maneuvering test, it is difficult to say anything definite from this figure, and the value of ηδ is almost the same when δ = 10° and 20°. 0.7
It can be seen that when δ=5°, the value becomes smaller as Δ and R become larger. Here it is as follows! I decided to go to school.

When APR≧5, ηδ=0.7 6=10', 2F1°, 35
゜ηδ = 0.5: When δ = 5゜ΔFll≦5, η,, = 0.7 (constant regardless of rudder angle) I-4 Coefficient of response model for ship speed reduction Is it ship speed reduction during turning motion? The response model, which is assumed to be proportional to the square of the turning angular velocity, is confirmed using actual ship data.

The ship's speed before turning is U. When the ship speed during steady turning motion is uBy, the ship speed reduction rate during steady turning = 1- U, t, y/UO'' ujty/uo (
8), find the ship speed reduction rate during steady turning motion at δ = 35° from existing data, and calculate the steady turning angular velocity r'
An example plotted against the square of *tv is shown in FIG. Newly built ships undergo a 35° δ-earth turning test during public trials, so we can use the record of changes in ship speed at that time, and considering the measurement accuracy in the actual line test, it is relatively well-organized. , δ=35°, the rate of decrease in ship speed during steady turning speed can be said to be proportional to r'2gjv. δ−3
If we know that the equivalent value of the index during steady turning motion at 5° is E35 or -35Mtv, we can estimate the rate of decrease in ship speed during steady turning motion using Figure 6, and find K'1. From equation (2), K ′u-11′gk, V/ ((l
The value of T'o can be obtained by analyzing the transient state of ship speed reduction, or by collecting more data since we are dealing with a nonlinear form coupled with turning angular velocity. Otherwise, you will not be able to obtain accurate values.

Using the value set for the turning angular velocity response model and the value of ′o determined from the ship speed reduction rate during steady turning motion,
Since the turning motion is not simulated, K′u/T
The value of ' was determined by trial and error and was approximately 0.77, which had little to do with the 8FH. K-EIS value is 8FH
Is it possible to find the rate of ship speed reduction during a steady turn for each type of ship as shown in the figure below? As there is only a small amount of data regarding the speed reduction rate, further investigation and consideration must be conducted.

(Example) 11. Fi Longitudinal motion simulation set When a main objective is given, the ship's maneuvering motion is simulated using existing data based on a response model of turning angular velocity and a response model of ship speed reduction. Then, we examine the applicability of the proposed estimation method.

278, which was often used in research on maneuverability, including in shallow water.
Taking the maneuverability test results of the 000 DWT tanker εsso 0saka as an example, using the proposed method and the organized data, we can calculate the turning motion of δ; 35° and the Z of δ = 20'.
Estimate the maneuvering motion. The main features of the vessel are as follows.

L ppm: 125.00IIB = 53.00m
d = 21.73sΔ= 319.040t
C, = 0.8293 L/B = 6.1
32A R/L d=1156.66 U,=7
．． 8 Kn=4. Ol m1s (1) The estimated main line of the steady turning characteristic is AP11 = 7.563, and the 4th
From the figure, K'EI%=1. :14 can be obtained.

Determining ζ- from the 314th, we find that ξ and '1-'s Oδ
0 is ξ,=2.2S ξ,,,=1.60
ξ2o = 1.21K 'E5 = 3.02
K'EIO=2.14 K'E2o=1.
62 is required. Therefore, r is δ r '5=0.264 r +o=O, :17:l
r2o=0.555r:I,=0.818, and a steady turning characteristic can be obtained.

Fig. 7 shows a comparison of the estimated values with the r'-6 curve obtained from the actual ship.

(2) Estimated early stage of turning trajectory of δ=35°
2. Start the simulation using the value of T''z, and when the turning motion develops and enters a steady turning, use the value of =.The time to transition from K'2 to '6 is determined by the turning angular velocity Either the maximum value is reached, and then the transition is carried out gradually in proportion to time, or the transition operation is stopped when the value of 'E' is reached.If η, 5 = 0.7, the value of 'E35 is set. Therefore, 'Z: 15 = 0.938, and from Figure 1, 'z/ T 'z = 0.58, so T'z"1
．． You can get 62. The values of U and tV are '-:I'
+ N l, = 0.084 to u, (-= 11.[
i3.1 becomes K ′,,= 1[1,2T ′,=
13.2.

In reality, for a response model in which the coefficient is set to 1 using existing data, identification is performed with reference to the measured values of the turning motion of the actual ship, and the final coefficients are set. In this method, it is easy to find the minimum value of the evaluation function because it is close to the initially set coefficient value or the final coefficient value. Here, we calculate the turning (M) wake using the initially set coefficient value as is, and while looking at the difference between the longitudinal path and lateral pressure of the turning wake obtained from the actual ship, we calculate the value of T'7. After adjusting and repeating the calculation several times, we finally set the coefficients of the response model as follows.

K′E35=IJ4K′,=0.9:18
T'z= 1.34Ku-]1.6 T',
=] 5.0 Estimated results of turning motion wake, turning angular velocity, and ship speed reduction, (Hydronautics Inc.:
Comparison of Results between
een Compute, er Simulat, 1 on
s and Full-scale Trials for
ESSO03AKA, submitted to 1
6th ITTC Maneuverability C
ol1mlt,ee.

Fig. 8 shows a comparison with calculated values obtained on an actual ship described in Working Paper (198 []). A fairly high degree of approximation was obtained even without identifying and finding the coefficients of the response model, and the accuracy is considered to be sufficient for practical use.

(3) The value of T'2 set by estimating the simulation turning motion wake of Z steering vibration at δ = 20° is 2'): 2-0
．． Since this value corresponds to 7, we decided to use this value also in the Z maneuvering motion, and finally set the coefficients of the response model as follows.

K't□o=1.541 r'20: 0.
538 to '2=1.078 T', =1.
54 K', = 11.5T'. We simulated the Z-steering motion with δ = 15.0, and the azimuth,
The estimated results of the turning angular velocity and ship speed reduction are shown in Fig. 9 in comparison with the measured values obtained from the actual ship. We believe that this figure provides sufficient results for practical use.

〔Effect of the invention〕

Utilizing the data on the maneuverability of actual ships that have been accumulated so far, we proposed the L method, which sets the coefficients of the response model of a new ship and estimates its maneuverability without conducting model experiments. Using this method, simulations of arbitrary ship maneuvering motions can be performed using an on-board personal computer, and results that are practically satisfactory can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the ratio of the K and Twi numbers obtained in the Z steering test and the ratio of the degree of obesity to the rudder area. Figure 2 is a diagram of the steady turning characteristic curve of an enlarged ship (equivalently, the definition of the ' index). FIGS. 3(a), (b), and (c) are relationship diagrams of each rudder angle ratio with respect to the equivalent index of the maximum rudder angle, and the ratio of the degree of fatness to the rudder area. Figure 4 is a diagram showing the relationship between the equivalent index of maximum rudder angle and the ratio of fertility to rudder area. FIGS. 5(a), (b), and (c) are relationship diagrams between the ratio of the equivalent index obtained from the turning test and the Z-steering test, and the ratio of the degree of fattening and the rudder area. Figure 6 shows the relationship between ship speed reduction rate and turning speed during steady turning motion.
Relationship diagram with power. FIG. 7 is a comparison diagram between the estimated value of the steady turning characteristic curve diagram of the enlarged ship and the measured value obtained from the actual ship. FIGS. 8(a), (b), and (c) are diagrams comparing estimated results of turning angular velocity, ship speed reduction, and turning motion track with measured values obtained from an actual ship. Figures 9(a) and 9(c) are diagrams comparing the estimation results of ship speed reduction, turning angular velocity, and azimuth angle with the measured values obtained on the actual ship. Patent applicant: Japan Air Flake Co., Ltd.
Person: Tetsu Shimizu and 2 other people: 20 years old, 5 years old, square diagram

Claims (1)

[Claims] (1) Based on the turning angular velocity response model and the ship speed reduction response model, assuming that the K index obtained from steady turning characteristics changes depending on the rudder angle, an equivalent K index including nonlinearity is defined, and the existing The equivalent K index for each rudder angle of the ship data and the ratio of K and T index obtained from the Z maneuver test are arranged against the ratio of the ship's fatness and the rudder area ratio, and the ship speed reduction rate is determined by the turning angular velocity. Let's organize it as being related to the square of . Furthermore, the relationship between the equivalent K index obtained from the turning test and the K index obtained from the Z maneuver test using existing data is determined. First, estimate the steady turning angular velocity at the maximum rudder angle of the new ship from existing data, use the organized data to determine the steady turning characteristics of the new ship, and then calculate the K and T indices for the Z maneuvering motion of the new ship. Set,
In the turning movement, it is assumed that the turning movement progresses to an equivalent K index as the turning progresses. Finally, there is a method for estimating maneuvering motion using a maneuverability index, which is characterized by identifying a set response model by referring to maneuverability test results conducted during a trial run of a new ship.