JPH057238B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention is directed to labor-saving marine autopilots,
This relates to improvements in steering characteristics and fuel efficiency.

<Prior Art> Conventional marine autopilots continuously estimate and calculate their own position based on a heading signal from a gyro compass, which is a heading signal generator, and move the ship on a set course around the yaw axis. Most of them adopted an automatic control method that allows them to board the vehicle using only attitude control. In other words, the difference between the ship's set course and heading by only controlling the attitude around the yaw axis, the set turn rate when changing course (the turn rate was manually set and output using a changeover switch, etc.), and the actually measured turn rate. The navigator used proportional, integral, and differential (hereinafter referred to as ``PID'') control to adjust the control gain so that the difference between the two became zero.

FIG. 3 is a block diagram showing a conventional example of such a marine autopilot. In the figure, 1 is the hull, 2 is a gyro compass that outputs a heading signal ψ, and 3 is a calculation unit that calculates and outputs a commanded rudder angle signal _U0 . This calculation unit 3 outputs a subtractor 4 that outputs a course deviation signal Δψ ₀ from the heading signal ψ and the set course signal ψm ₀ , and a turn rate signal ψ〓 (.denotes the first-order differential; the same applies hereinafter). The turn rate calculation unit 5 (in the figure, the heading signal ψ is differentiated using a differentiator circuit, but a separate turn rate meter (not shown) may be used) and the turn rate signal ψ a subtracter 51 that calculates the difference from the set turn rate signal ψ〓m ₀ set to 0 and outputs a turn rate deviation signal Δψ〓 ₀ ; The course deviation F signal Δψ^ ₀ filtered by the filter unit 6 (F represents filtering, and ∧ represents the calculated value (estimated value).
(same below) and turn rate deviation F signal Δψ^ ₀
It consists of a PID calculation circuit 7 that performs PID calculation and outputs a commanded steering angle signal _U0 . Reference numeral 8 denotes a steering device that drives the rudder 9 based on the commanded rudder angle signal U ₀ .

The steering function of the marine autopilot having such a configuration will be explained below.

The subtracter 4 compares the heading signal ψ and the set course signal ψm ₀ and outputs a course deviation signal Δψ ₀ to the input filter section 6 . Further, the subtracter 51 compares the turn rate signal ψ〓 and the set turn rate signal ψ〓m ₀ and outputs a turn rate deviation signal Δψ〓 ₀ to the input filter section 6 . The course deviation signal Δψ ₀ and the turn rate deviation signal Δψ〓 ₀ are filtered based on the filter setting value Mf manually set in advance in the input filter section 6, and the course deviation signal Δψ^ ₀ and the turn rate deviation F signal Δψ are filtered. ^ It is guided to the PID calculation circuit 7 as ₀ . The PID calculation circuit 7 calculates a course deviation F signal Δψ^ ₀ and a turn rate deviation F signal Δψ^ ₀ based on control parameters Mg (for example, PID control gain and time constant) that are manually set by the navigator from the outside. PID
It is calculated and output to the steering gear 8 as a commanded rudder angle signal _U0 to drive the rudder 9.

<<Problems to be Solved by the Invention>> By the way, the marine autopilot having such a configuration has the following problems.

In the PID calculation circuit 7, the control parameters
Since Mg is manually set by the navigator from the outside, it is not easy to always adjust the control parameter Mg to an appropriate value in response to changes in the motion characteristics of the hull 1. If the control parameter Mg cannot be adjusted to an appropriate value, it will be difficult to obtain the desired control characteristics, that is, high course-keeping ability (course maintenance) and high course-changing ability (course change), and therefore high transportation reliability cannot be expected, and pilot It is also difficult to achieve fuel efficiency in the system.

Even if it were possible to adjust the control parameter Mg to an appropriate value, the burden placed on the navigator who must adjust the control parameter Mg in response to changes in weather and sea conditions would be extremely heavy. This is especially noticeable in the case of ships with unstable courses, such as oversized ships.

Since the input filter section 6 is composed of a temporary lag (or second-order lag) filter, a sufficient filtering effect cannot be obtained, and the steering characteristics and fuel efficiency deteriorate.

During a course change, the difference between the set turn rate and the measured turn rate is detected, and a constant set turn rate signal is maintained according to this difference until the end of the course change, which prevents large overshoots due to the influence of inertia of the ship. I wake up. If there is a large overshoot while navigating in a narrow channel, there will be dangers such as collision with other ships or being stranded on the opposite shore.

The present invention has been made in view of the above-mentioned problems, and allows navigators to set an optimal control gain that minimizes fuel consumption while satisfying high course-keeping performance and high course-changing performance for the ship. The purpose of the present invention is to provide a marine autopilot that can automatically make decisions without requiring the operator's assistance, and that enables optimal operation at all times even when the ship's motion characteristics change. shall be.

<Means and effects for solving the problems> The marine autopilot of the present invention is configured to obtain a steering angle signal optimal for the ship to be controlled based on a heading signal, a turn rate signal, and a rudder angle signal. The structure and function are as follows.

First invention: A filter section removes high frequency components harmful to steering from the heading signal and turn rate signal. A hull characteristic estimation calculation section calculates and outputs an estimated hull parameter, which is an estimated value of the hull characteristic and includes a coefficient of the cube of the turn rate, from the heading signal, the turn rate signal, and the rudder angle signal, and outputs the estimated hull parameter, which is an estimated value of the hull characteristic and includes a coefficient of the cube of the turn rate. The corresponding optimum gain is output from the course keeping/changing course optimum gain adjustment section. In the course keeping course change optimum operation amount calculation section, a control gain is set by this optimum gain output, and an optimum steering angle signal is output by performing calculation on the course direction signal and turn rate signal which have passed through the filter section.

Second invention: First, in the hull characteristic estimation calculating section, an estimated hull parameter that is an estimated value of the hull characteristic and includes a coefficient of the cube of the turn rate is calculated and output from the heading signal, the turn rate signal, and the rudder angle signal. The hull motion estimation calculation unit inputs the heading signal, the turn rate signal, and the rudder angle signal, and uses a hull model that has a cube term of the turn rate and whose coefficients are set by the estimated hull parameter signal. The motion of the ship is estimated and calculated, and an estimated course direction signal and an estimated turn rate signal are output. The course-keeping and course-changing optimum gain adjustment section outputs an optimum gain corresponding to the estimated hull parameter signal, and the course-keeping and course-changing optimum operation amount calculation section has a control gain set by this optimum gain output, and the ship motion estimation calculation section The optimum steering angle signal is output by performing calculations on the estimated course heading signal and estimated turn rate signal input from the

Third invention: First, the hull characteristic estimation calculation section calculates and outputs estimated hull parameters, which are estimated values of the hull characteristics and include coefficients of the cube of the turn rate, from the heading signal, the turn rate signal, and the rudder angle signal. The hull motion estimation calculation unit inputs the heading signal, the turn rate signal, and the rudder angle signal, and uses a hull model that has a cubic term of the turn rate and whose coefficients are set by the estimated hull parameter signal. The motion of the ship is estimated and calculated, and an estimated course direction signal and an estimated turn rate signal are output. The wave disturbance frequency determining section inputs the estimated hull parameters, determines a wave disturbance frequency, and outputs a wave disturbance frequency signal. The wave disturbance estimation calculation unit calculates the magnitude of wave disturbance acting on the hull at a frequency that can be controlled by the hull from the heading signal, the turn rate signal, the rudder angle signal, the wave disturbance frequency signal, and the estimated hull parameters. Perform estimation calculation. The sea condition determination section inputs the turn rate signal and the wave disturbance frequency signal, determines the sea condition based on the state of the wave disturbance, and outputs a determined wave disturbance frequency. The course keeping course change optimum gain adjustment section outputs an optimum gain corresponding to the estimated hull parameter signal inputted from the ship characteristic estimation calculation section, and the course keeping course change optimum operation amount calculation section sets a control gain based on this optimum gain output. and performs calculations on the estimated course direction signal and estimated turn rate signal input from the hull motion estimation calculation section. The wave disturbance optimum gain adjustment section outputs an optimum gain corresponding to the determined wave disturbance frequency output of the sea condition judgment section, and the wave disturbance optimum operation amount calculation section sets a control gain based on this optimum gain output, and adjusts the wave disturbance. A calculation is performed on the estimated wave disturbance signal input from the estimation calculation section. The combined optimum operation amount calculation section adds the operation amount outputs from the course keeping course change optimum operation amount calculation section and the wave disturbance optimum operation amount calculation section and outputs an optimum steering angle signal.

《Embodiments of the invention》 This will be explained in detail below using the drawings.

FIG. 1 is a block diagram showing an embodiment of the marine autopilot of the present invention, and FIG. 2 is a flowchart for explaining the operation of the apparatus shown in FIG. In FIG. 1, parts and functions that overlap with those in FIG. 3 are given the same numbers and symbols, and their explanations are omitted.

In Fig. 1, 10 is the estimated value of the hull characteristics from the heading signal ψ, the turn rate signal ψ〓, and the rudder angle signal δ, and the estimated hull parameters α^, β^, γ including the coefficients of the cubic term of the turn rate. ^ (∧ means estimated value)
A hull characteristic estimation calculation unit 11 inputs the heading signal ψ, the turn rate signal ψ〓, and the rudder angle signal δ, and outputs the cube term of the turn rate and the estimated hull parameter signal α^. , a hull motion estimation calculation unit 12 that estimates and calculates the motion of the hull 1 using a hull model whose coefficients are set by , β^, and γ^ and outputs an estimated course direction signal ψ^ and an estimated turn rate signal ^;
13 is a wave disturbance frequency determination unit that inputs the turn rate signal ψ〓 and the estimated hull parameter signals R^, β^, and determines and outputs the wave disturbance frequencies ω ₁ , ω ₂ ; Turn rate signal ψ〓, the steering angle signal δ, and the wave disturbance frequency signals ω ₁ , ω ₂
and a wave disturbance estimation calculation unit that estimates and calculates the magnitude of wave disturbance acting on the hull 1 at a frequency that can be controlled by the hull 1 from the estimated hull parameter signals R^ and β^; 14 is the turn rate signal ψ〓; A sea condition determining unit inputs the wave disturbance frequency signals ω ₁ and ω ₂ , determines the sea condition based on the state of the wave disturbance, and outputs a determined wave disturbance frequency; 15 is an estimated hull input from the hull characteristic estimation calculation unit 10; parameter signal
A course keeping course change optimum gain adjustment section outputs the optimum gain 〓1 corresponding to R^, β^, and 16 is the optimum gain output 〓1 from this course keeping course change optimum gain adjustment section 15.
17 is the sea condition determination unit; the control gain is set by the above-mentioned ship motion estimation calculation unit 11; A wave disturbance optimum gain adjustment section 18 outputs an optimum gain 〓2 corresponding to the output of 14, and 18 has a control gain set by the optimum gain output 〓2 from this wave disturbance optimum gain adjustment section 17, A wave disturbance optimum operation amount calculation section 19 performs calculations on the estimated wave disturbance signal W^d inputted from the estimation calculation section 13; Manipulated amount output
This is a composite optimal operation amount calculation unit that adds Uδ ₁ and Uδ ₂ and outputs an optimal steering angle signal Uδ.

Each of these parts will be explained in more detail below based on FIGS. 1 and 2.

<Ship motion estimation calculation unit 11> The hull motion estimation calculation unit 11 inputs the heading signal ψ, turn rate signal ψ〓, and rudder angle signal δ, and generates an estimated course heading signal ψ^ and an estimated turn rate signal ψ using the following equation. Estimate calculation of ^.

dψ^(t)/dt=−R^(t)ψ^(t)+β^(t)δ(
t)+
β^(t) W^d(t) + 3γ^(t) (ψ^(t)) ³ −γ^
(t) (ψ^
(t)) ³ +K ₁₁ (ψ〓(t)−ψ^(t))+K ₁₂ (ψ(
t) −ψ^
(t)+K ₁₁ V ₁ (t)+K ₁₂ V ₂ (t) …(1) dψ^(t)/dt=ψ^(t)+K ₂₁ (ψ〓(t)−ψ^(
t))+K ₂₂
(ψ(t)−ψ^(t))+K ₂₁ V ₁ (t)+K ₂₂ V ₂ (t)
…(2) However, R^(t) = α^(t) + 3γ^(t) (ψ^(t)
) ² ...(3), α^(=1/Tv; Tv is the followability index), β^(=Kv/
Tv; Kv is a turning performance index), γ^ (coefficient of nonlinear term) is a parameter of the hull itself estimated by the hull characteristic estimation calculation unit 10 described later, and W^d is estimated by the wave disturbance estimation calculation unit 13 described later. Estimated values of wave disturbance, v ₁ , v ₂
is the measurement noise and t is the time.

Estimation formulas (1) to (3) include the cube term of the turn rate ψ〓 in the mathematical model for turning the ship considering the case of a ship with an unstable course such as a large ship, and equivalently calculates yawing due to disturbance. wave disturbance by replacing it with a certain rudder angle.
Formula for Wd ψ¨(t) + αψ〓(t) + γ(ψ〓(t)) ³ = β
δ(t))+βWd
(t) ...(4) and is obtained by applying the well-known (extended) Kalman filter theory to a linear approximation of this. This results in Kalman gain K ₁₁ ~
K ₂₂ is determined to minimize the variance of ψ−ψ^, ψ〓−ψ^.

<Hull characteristics estimation calculation unit 10> The hull characteristics estimation calculation unit 10 calculates estimated hull parameters α^, β^, γ^, which are estimated values of the hull characteristics, from the heading signal ψ, turn rate signal ψ〓, and rudder angle signal δ. Said (1)
Estimation calculations are performed using equations (2) and (3) and the following equations (5), (6), and (7).

dα^(t)/dt=K ₃₁ (ψ〓(t)−ψ^(t))+K ₃₂
(ψ(t)
−ψ^(t))+K ₃₁ v ₁ (t)+K ₃₂ v ₂ (t)…(5) dβ^(t)/dt=K ₄₁ (ψ〓(t)−ψ^(t))+K ₄₂
(ψ(t)
−ψ^(t))+K ₄₁ v ₁ (t)+K ₄₂ v ₂ (t)…(6) dγ^(t)/dt=K ₅₁ (ψ〓(t)−ψ^(t))+K ₅₂
(ψ(t)
−ψ^(t))+K ₅₁ v ₁ (t)+K ₅₂ v ₂ (t)…(7) These equations represent the hull model using equation (4) as above, and also the hull parameters α, β, and γ. It can be obtained by treating it as an unknown quantity and applying the (extended) Kalman filter theory to it. In this case, the Kalman gains K ₁₁ ~ _{K 52} are ψ−ψ^, ψ〓−ψ^, α−
It is determined to minimize the variance of α^, β−β^, and γ−γ^.

If the calculation speed of the above-mentioned hull characteristic estimation calculation section 10 is made faster than that of the hull motion estimation calculation section 11, mutual interference can be eliminated and the operating characteristics can be improved.

<Wave disturbance frequency determination unit 12> When the sea condition changes, the wave disturbance frequency determination unit 12, which inputs the estimated hull parameters R^, β^ and the turn rate signal ψ〓 from the hull characteristic estimation calculation unit 10, , the controllable wave disturbance frequency for the hull 1 is determined.

That is, first, a low frequency band in which the hull 1 is controllable (or responsive) is determined from the estimated hull parameters R^ and β^. Next, the turn rate signal containing random noise (average value is 0) of the hull 1 is subjected to Fourier transformation to obtain a frequency spectrum related to the turn rate ψ〓. Find the frequencies ω ₁ and ω ₂ at which this frequency spectrum takes the maximum value (the value that most affects the ship's course-keeping ability) and the second value (more precisely, the angular frequency) in the low frequency band, and calculate these. Output as wave disturbance frequency.

In the above example, only the first and second frequency components in the low frequency band are determined as the wave disturbance frequency, but the invention is not limited to this, and the third and subsequent frequency components can be further added and described later. It may be used for estimating wave disturbance. In this way, the feedforward control characteristics regarding wave disturbances are further improved.

<Wave disturbance estimation calculation unit 13> The wave disturbance estimation calculation unit 13 calculates the heading signal ψ, the turn rate signal ψ〓, the rudder angle signal δ, the estimated hull parameters R^, β^ from the hull characteristic estimation calculation unit 10, and the waves. By inputting the wave disturbance frequencies ω ₁ and ω ₂ outputted from the disturbance frequency determination unit 12, the magnitude of the wave disturbance Wd at a frequency that can be controlled by the hull 1 is determined by the above equations (1), (2), and (3). Then, estimate calculation is performed using the following equations (8), (9), (10), and (11).

dψ^ ₁₂ (t)/dt=-ω ₁ x^ ₁₂ (t)+K ₆₁ (ψ〓(t)
−ψ^
(t))+K ₆₂ (ψ(t)−ψ^(t))+x^ ₂₂ (t)+
_{K61v1 _}
(t)+K ₆₂ v ₂ (t) …(8) dx^ ₁₂ (t)/dt=ψ^ ₁₂ (t)+K ₇₁ (ψ〓(t)−ψ^
(t))+
K ₇₂ (ψ(t)−ψ^(t))+K ₇₁ v ₁ (t)+K ₇₂ v ₂ (t
)
…(9) dψ^ ₂₂ (t)/dt=−ω ₂ x^ ₂₂ (t)+K ₈₁ (ψ〓(t)
−ψ^
(t))+K ₈₂ (ψ(t)−ψ^(t))+K ₈₁ v ₁ (t)
_{＋ K82v2}
(t) …(10) dx^ ₂₂ (t)/dt=ψ^ ₂₂ (t)+K ₉₁ (ψ〓(t)−ψ^
(t))+
K ₉₂ (ψ(t)−ψ^(t))+K ₉₁ v ₁ (t)+K ₉₂ v ₂ (t
)
...(11) However, W^d(t)=x^ ₁₂ (t) These equations are similar to those described above, in which the hull model is expressed by equation (4), and the wave disturbance model equation is expressed by two frequencies ω ₁ and ω ₂ . It is expressed by the following equations (12), (13), and (14) composed of a sine wave and white noise Wr, and is obtained by applying the Kalman filter theory to this.

x ₁₂ (t)=Wd(t)...(12) X¨ ₁₂ (t ₎ =-ω ₁ x ₁₂ (t) ₊ x ₂₂ (t)...(13 ₎ (t) + Wr (t) ...(14) In this case, Kalman gain K ₆₁ ~ _{K 92} is ψ−ψ^, ψ〓
−ψ^, x ₁₂ −x^ ₁₂ , x〓12−ψ^ ₁₂ , x ₂₂ −x^ ₂₂ , x〓22−
ψ^ ₂₂
is determined to minimize the variance of

<Sea conditions determination unit 14> If the sea conditions change, the state of wave disturbance Wd also changes, and the magnitude of wave disturbance Wd must be estimated again, and the amount of wave disturbance feed forward must also be changed. . The sea condition determining section 14 inputs the turn rate signal ψ〓 and the wave disturbance frequencies ω ₁ and ω ₂ determined by the wave disturbance frequency determining section 12 and determines the state of the sea conditions.

That is, the sea condition determination unit 14 Fourier transforms the turn rate signal to obtain the power spectrum density S(n)(n
is the spectral order). As described below,
The maximum value of this power spectrum density S(n) is
Predetermined setting values Φwd ₀ , Φwd ₁ ,
By comparing with Φwd ₂ , determine the sea level at that time.

In the case of CALM SEA (mirror-smooth sea conditions with visible wave heights of about 0 to 0.1 m), MAX[S(n)]≦Φwd ₀ ...(15) Therefore, wave disturbance estimation and control are basically Don't do it as a.

In the case of ROUGH SEA (a sea condition in which waves are relatively high with a visual wave height of about 2.5 to 4 m), Φwd ₀ < MAX[S(n)] ≦ Φwd ₁ (16), so wave disturbance is estimated.

VERY ROUGH SEA (visual wave height 4.0~6m)
In the case of a sea condition in which the waves are quite high, Φwd ₁ < MAX [S(n)] ≦ Φwd ₂ (17), so the wave disturbance is estimated.

In the case of HIGH ROUGH SEA (very rough sea conditions with a visual wave height of 6 m or more), Φwd ₂ < MAX [S(n)] ...(18) Therefore, wave disturbance estimation and In principle, no control is performed.

In the above case, the determined wave disturbance frequency ω ₁₀
= ω ₁ , ω ₂₀ = ω ₂ as the wave disturbance optimum gain adjustment unit 17
Output to.

Although the above-mentioned sea condition determination unit 14 uses a turn rate signal, it may be configured to perform Fourier transform on the estimated wave disturbance W^d.

<Course-keeping and course-changing optimum gain adjustment section 15> The course-keeping and course-changing optimum gain adjustment section 15 inputs R^ and β^ estimated by the hull characteristic estimation calculation section 10, and calculates the size, weight, and instability of the ship. The optimal feedback gain corresponding to the degree of power, etc. is selected from the optimal gain table and output as a gain matrix 〓1. As the optimal gain table, a ROM or the like is used in which the optimal feedback gains determined for each class of ships are written in advance.

<Route-keeping and course-changing optimum operation amount calculation section 16 > The course-keeping and course-changing optimum operation amount calculation section 16 calculates the optimum feedback gain determined by the course-keeping and course-changing optimum gain adjustment section 15 = 1 = (K _1P , K _1D , K _1I , K _C1 ,
K _C2 ), and the set turn rate ψ〓m ₀ , the set course heading ψm ₀ , the estimated course direction signal ψ^ from the hull motion estimation calculation unit 11, and the estimated turn rate signal 〓 are calculated using the following equation. By multiplying as shown, the first manipulated variable Uδ ₁ (t) is calculated and output.

Uδ ₁ = −K _1P ψ^−K _1D ψ^−K _1I ∫｛ψ^−ψm ₀ ｝dt)＋
K _C1 ψm ₀ +K _C2 ψ〓m ₀ ...(19) However, when the course is kept, ψ〓m ₀ = 0.

This first manipulated variable Uδ ₁ changes the steering angle so as to reduce the influence of disturbances on the hull caused by cargo and the like.

<Wave disturbance optimum gain adjustment unit 17> The wave disturbance optimum gain adjustment unit 17 uses the determined wave disturbance frequency ω ₁₀ which is the output value of the sea condition determination unit 14,
Input ω ₂₀ , select the optimal feed forward gain from the optimal gain table, and create the gain matrix 〓
Output as 2. As an optimal gain table,
The optimum feed forward gain corresponding to various sea conditions is written in ROM etc. in advance.

<Wave disturbance optimum operation amount calculation unit 18> The wave disturbance optimum operation amount calculation unit 18 calculates the optimum feed forward gain determined by the wave disturbance optimum gain adjustment unit 17 = 2 = K ₂₁ , K ₂₂ , K ₂₃ , _K24 )
Input this and the wave disturbance estimation calculation unit 13
The second manipulated variable Uδ ₂ (t) is calculated and output by multiplying the estimated wave disturbance values W^d, ψ^ ₁₂ , x^ ₂₂ , ψ^ ₂₂ from the equation as shown in the following equation. Uδ ₂ = −K ₂₁ W^d
-K ₂₂ ψ^ ₁₂ -K ₂₃ x^ ₂₂ -K ₂₄ ψ^ ₂₂ (20) This second manipulated variable Uδ ₂ (t) changes the steering angle so as to reduce the influence of wave disturbance.

<Composite optimum operation amount calculation unit 19> The combination optimum operation amount calculation unit 19 calculates the first operation amount output from the course-keeping and heading change optimum operation amount calculation unit 16.
Uδ ₁ and the second manipulated variable Uδ ₂ outputted from the wave disturbance optimal manipulated variable calculating section 18 are added as shown in the following formula, and an optimal steering angle signal Uδ is output to the steering gear 8.

Uδ=Uδ ₁ +Uδ ₂ ...(21) The above-mentioned course-keeping and course-changing optimum gain adjustment section 15, course-keeping and course-changing optimum operation amount calculation section 16, wave disturbance optimum gain adjustment section 17, wave disturbance optimum operation amount calculation section 18, composite optimization The manipulated variable calculation unit 19 operates according to the algorithm shown below.

Estimating the equation of motion (4) of the hull Turn rate ψ〓(t)
When expanded and linearly approximated, ψ¨(t)=-R(t)ψ〓(t)+βδ(t)+β
(t)
…(22) becomes. However, R(t)=α(t)+3γ(t)(ψ^(t)) ² …(23) (t)=Wd(t)+3γ(t)(ψ^(t)) ³ /β
…(24) Furthermore, the relational expression e〓 ₁ (t)=ψ(t)−ψm ₀ (t) …(25) e〓 ₂ (t)=ψ〓(t)−ψ〓m ₀ (t) …( 26) Add ψ〓m ₀ (t)=0 …(27) ψ¨m ₀ (t)=0 …(28). For the controlled object consisting of the above equations (22) to (28) and the wave disturbance model equations (12), (13), and (14), δ that minimizes the evaluation function J of the following equation is calculated using the known optimal regulator theory. By finding it using
Determine the optimal feedback gain =1 and the optimal feedback gain =2.

J=E[∫｛λ ₁ (ψ−ψm ₀ ) ² +λ ₂ (ψ〓−ψ〓m ₀ ) ²
+λ ₃ (∫
(ψ−ψm ₀ )dt) ² +λ ₄ δ ² }dt] (29) where E[ ] represents the collective average. Evaluation function J
represents energy saving, course maintenance, and course changeability.

The above analysis is performed in advance for various wave disturbances and various hulls (R, β), and the optimal gain matrix 〓1=(K _1P , K _1D , K _1I , K _C1 , K _C2 , 〓2=K ₂₁ ,
K ₂₂ , K ₂₃ , K ₂₄ ) are tabulated in the course keeping/changing course optimum gain adjustment unit 15 and the wave disturbance optimum gain adjustment unit 17 so that they can be referenced from the hull parameters (R^, β^) and sea condition judgment output. .

Here, R^(t) = α^(t) + 3γ^(t) (ψ^(t)
) ² , and α^ and γ^ have a constant steady-state solution, but since ψ^(t) oscillates around the zero point, R^ also oscillates around α^. It is desirable that the reference information for adjusting the gain has a constant value, so the root mean square of R^ Let be the value of R^ for reference. Even if R^ is oscillating, if the nature of the vibration is steady, RMSR^ will also be a steady value.

As shown in the flowchart of Fig. 2, at the start of the above embodiment, initial values R^(O) and β^(O) of estimated values of hull characteristics are set, and these are used for calculation. There is.

Further, in the above embodiment, the hull motion estimation calculation unit 11
Although an (extended) Kalman filter is used as an example, the present invention is not limited to this, and it is also possible to use a normal analog filter.

If the wave disturbance is not estimated, the wave disturbance frequency determining section 12, the wave disturbance estimation calculation section 13,
Sea condition determination unit 14, wave disturbance optimum gain adjustment unit 1
7. The wave disturbance optimum operation amount calculation unit 18 can be omitted;
The configuration can be made simpler.

Furthermore, in the embodiment described above, many optimal control gains are calculated in advance, stored as a gain table (memory storage format), and used as the estimated hull parameters R^, β^ and the determined wave disturbance frequency ω ₁₀ , ω ₂₀ has been described, but it is not necessarily necessary to perform the selection in a table format like this, and the calculation of the optimal control gain matrix 〓1 may be performed online.

In the above embodiment, the course-keeping and course-changing optimum gain adjustment section 15, the course-keeping and course-changing optimum operation amount calculation section 16, the wave disturbance optimum gain adjustment section 17, the wave disturbance optimum operation amount calculation section 18, and the combined optimum operation amount calculation section 19 are configured. The parts may be collectively configured by a microcomputer. Further, each of the other parts can be similarly configured by a microcomputer.

It should be noted that the present invention may have a structure in which a ship speed signal is used, that is, a structure in which the ship speed signal is incorporated into the ship characteristics estimation calculation section to estimate the ship characteristics. In this way, correction values corresponding to changes in ship speed can be obtained, thereby further improving the accuracy of the present system.

Also, without using the turn rate ψ〓 as an input to the estimation calculation unit,
It is also possible to perform each estimation calculation using only the heading signal ψ. Also, as an input to each estimation calculation section,
Instead of the heading signal ψ and the turn rate signal ψ〓, the heading deviation ψm ₀ −ψ and the turn rate deviation ψ〓
=ψ〓m ₀ −ψ〓 can also be used.

<<Effects of the Invention>> As described above, according to the first invention, the steering characteristics that change depending on the weight and size of the ship are automatically controlled by the ship characteristics estimation calculation unit that estimates the characteristics of the ship. Therefore, even if the hull characteristics such as hull mass change due to changes in cargo or ballast, it is possible to perform steering that follows the changes.

Therefore, stable steering can be achieved without overshooting when changing course.

According to the second aspect of the invention, since the hull motion estimation calculation section is provided which estimates and calculates the hull motion using a hull model having a cubic term of the turn rate, even if the ship is of an enlarged type and has an unstable course. It is possible to achieve energy-saving navigation and optimal course-keeping characteristics that match the characteristics of the ship.

According to the third invention, since the steering characteristics are directly feed-forward controlled from wave disturbances by performing estimation calculations using a Kalman filter that varies depending on changes in weather and sea conditions, it is possible to obtain a control amount corresponding to wave disturbances. I can do it.

This eliminates the need for the navigator to adjust the control gain by looking at the weather and sea conditions, which reduces the burden on the navigator and enables accurate steering without being affected by wave disturbances.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a marine autopilot according to the present invention, Fig. 2 is a flowchart of Fig. 1,
FIG. 3 is a block diagram showing a conventional example of a marine autopilot. 1...Hull, 10...Hull characteristic estimation calculation section, 1
DESCRIPTION OF SYMBOLS 1... Hull motion estimation calculation part, 12... Wave disturbance frequency determination part, 13... Wave disturbance estimation calculation part, 14
... Sea condition determination section, 15 ... Course keeping course change optimum gain adjustment section, 16 ... Course keeping course change optimum operation amount calculation section, 17
... Wave disturbance optimum gain adjustment section, 18 ... Wave disturbance optimum operation amount calculation section, 19 ... Combined optimum operation amount calculation section, ψ ... Heading signal, ψ = ... Turn rate signal, δ ... Rudder angle Signal, Uδ... Steering angle signal, α^,
β^, γ^, R^... Estimated hull parameters, ψ... Estimated course heading signal, ψ^... Estimated turn rate signal, ω ₁ ,
ω ₂ ... Wave disturbance frequency, Wd ... Size of wave disturbance, ω ₁₀ , ω ₂₀ ... Judgment wave disturbance frequency, 〓1,
〓2...optimal gain, W^d...estimated wave disturbance signal.

Claims (1)

[Scope of Claims] 1. In a marine autopilot configured to obtain a steering angle signal optimal for a ship to be controlled based on a heading signal, a turn rate signal, and a rudder angle signal, from the heading signal and the turn rate signal. a filter unit that excludes high-frequency components harmful to steering; and calculating estimated hull parameters that are estimated values of hull characteristics and include coefficients of the cube of the turn rate from the heading signal, the turn rate signal, and the rudder angle signal. a hull characteristic estimation calculation unit that outputs the estimated hull parameter signal; a course-keeping course change optimum gain adjustment unit that outputs an optimum gain corresponding to the estimated ship parameter signal inputted from the ship characteristic estimation calculation unit; and a course-keeping course change optimum gain adjustment unit that outputs the a course-keeping and course-changing optimum operation amount calculation unit that has a control gain set by the optimum gain output, performs calculations on the course heading signal and turn rate signal that have passed through the filter unit, and outputs an optimum steering angle signal; A marine autopilot characterized by comprising: 2. The marine autopilot according to claim 1, wherein the hull characteristic estimation calculation section is configured with a Kalman filter. 3. In a marine autopilot configured to obtain a steering angle signal optimal for a ship to be controlled based on a heading signal, a turn rate signal, and a rudder angle signal, the steering angle signal is determined based on the heading signal, turn rate signal, and rudder angle signal. a hull characteristic estimation calculation unit that calculates and outputs an estimated hull parameter that is an estimated value of the characteristic and includes a coefficient of the cube term of the turn rate, and inputs the heading signal, the turn rate signal, and the rudder angle signal to perform a turn. a hull motion estimation calculation unit that estimates the motion of the hull using a hull model having a cube term of rate and whose coefficients are set by the estimated hull parameter signal, and outputs an estimated course heading signal and an estimated turn rate signal; , a course keeping course change optimum gain adjustment section that outputs an optimum gain corresponding to the estimated ship parameter signal inputted from the ship characteristic estimation calculating section; and a control gain based on the optimum gain output from the course keeping course change optimum gain adjustment section. and a course-keeping course change optimum operation amount calculation unit that performs calculations on the estimated course direction signal and the estimated turn rate signal inputted from the hull motion estimation calculation unit and outputs an optimum steering angle signal. Characteristic marine autopilot. 4. The marine autopilot according to claim 3, wherein the hull characteristic estimation calculation section and the hull motion estimation calculation section are constructed with a Kalman filter. 5. In a marine autopilot configured to obtain a steering angle signal optimal for a ship to be controlled based on a heading signal, a turn rate signal, and a rudder angle signal, the steering angle signal is determined based on the heading signal, turn rate signal, and rudder angle signal. a hull characteristic estimation calculation unit that calculates and outputs an estimated hull parameter that is an estimated value of the characteristic and includes a coefficient of the cube term of the turn rate, and inputs the heading signal, the turn rate signal, and the rudder angle signal to perform a turn. A hull motion estimation calculation unit that estimates the motion of the hull using a hull model having a cube term of rate and whose coefficients are set by the estimated hull parameter signal, and outputs an estimated course heading signal and an estimated turn rate signal. a wave disturbance frequency determination unit that inputs the turn rate signal and the estimated hull parameters, determines a wave disturbance frequency, and outputs a wave disturbance frequency signal; and a wave disturbance estimation calculation unit that estimates and calculates the magnitude of wave disturbance acting on the ship body at a frequency that the ship body can control from the wave disturbance frequency signal and the estimated ship parameter; and the turn rate signal and the wave disturbance frequency signal. a sea condition determining unit that inputs the wave disturbance, determines the sea condition based on the state of the wave disturbance, and outputs a determined wave disturbance frequency; and a course-keeping unit that outputs an optimal gain corresponding to the estimated hull parameter signal input from the hull characteristic estimation calculation unit. A control gain is set by the optimum gain output from the course change optimum gain adjustment section and the course keeping course change optimum gain adjustment section, and is calculated on the estimated course azimuth signal and estimated turn rate signal input from the ship motion estimation calculation section. a wave disturbance optimum gain adjustment section that outputs an optimum gain corresponding to the output of the sea condition determination section; and a wave disturbance optimum gain adjustment section that outputs the optimum gain from the wave disturbance optimum gain adjustment section. a wave disturbance optimum operation amount calculation section that has a control gain set and performs calculations on the estimated wave disturbance signal input from the wave disturbance estimation calculation section; the course keeping course change optimum operation amount calculation section and the wave disturbance optimum operation amount calculation section A marine autopilot, comprising: a composite optimum operation amount calculation section that adds operation amount outputs from the two and outputs an optimum steering angle signal; 6. The marine autopilot according to claim 5, wherein the hull characteristic estimation calculation section, the hull motion estimation calculation section, and the wave disturbance estimation calculation section are constructed with Kalman filters.