JP2017178052A - Automatic steering device for ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a variation of a nozzle for a water jet propulsion ship by reducing the influence of a dead zone of the nozzle.SOLUTION: An automatic steering device for a ship outputs a command steering angle by using a hull parameter based on a reference azimuth and a bow azimuth to a water jet propulsion ship having a water jet propulsion machine having at least a pair of nozzles, and comprises an identification computing unit for identifying the hull parameter. The identification computing unit comprises an identification model that outputs model output data from predetermined input data provided by the automatic steering device for a ship, and a parameter adjustment unit for adjusting and identifying the hull parameter from a result of comparison between the model output data from the identification model and output data, which is a measured value for the hull. The identification model includes a nozzle model and a hull motion model. The nozzle model incorporates a one-side width of a dead zone of the pair of nozzles and the gain ratio of the dead zone to gain except for the dead zone. The identification computing unit handles the dead zone width and the gain ratio as parameters to be identified together with the hull parameter relating to the hull motion model.SELECTED DRAWING: Figure 8

Description

  The present invention relates to control of a water jet propulsion ship.

  It is said that a water jet propulsion ship that obtains propulsive force by a nozzle that injects a water flow is suitable for high-speed navigation, although it is less energy efficient than a propeller ship. In some water jet propulsion ships, nozzles are provided in pairs on the left and right, and the water jet propulsion ship changes the needle by tilting these nozzles.

  In the course of a water jet propulsion ship, the nozzle has a dead zone within a predetermined angle inclined left and right from the straight direction in which the ship moves straight. As a technique for removing such a dead zone, there is known a compensation method for a steering system having a dead zone characteristic, in which a dead zone parameter of a steering system is estimated and a parameter of a dead zone reverse characteristic is given to a command steering angle (see Patent Document 1). ).

US Patent Application Publication No. 2007 / 0050113A1

  However, according to the compensation method described above, there is a problem in that since the nozzle change corresponding to the dead zone is given to the inclination of the nozzle of the water jet propulsion ship, this may become a heavy load and cause failure or wear.

  An embodiment of the present invention is made to solve the above-described problems, and is an automatic steering apparatus for a ship that can further reduce the influence of a dead zone of a nozzle in a water jet propulsion ship and suppress the fluctuation of the nozzle. The purpose is to provide.

In order to solve the above-described problem, the marine vessel automatic steering apparatus according to the present embodiment sets a hull parameter based on a reference direction and a heading direction for a water jet propulsion ship including a water jet propulsion device having at least a pair of nozzles. An automatic steering device for a ship that outputs a command rudder angle using an identification calculation unit that identifies the hull parameter, the identification calculation unit being a model based on predetermined input data obtained by the automatic steering device for a ship An identification model for outputting output data, a model output data from the identification model, and a parameter adjustment unit that adjusts and identifies the hull parameters from a comparison result of output data that is actual measurement values related to the hull, identification model includes a nozzle model and ship motion model, the nozzle model outputs steering angle [delta], a [delta] _c instruction steering angle, [delta] _D The nozzle offsets, W one side width of the dead zone of the pair of nozzles, as a gain ratio of the dead band for the gain outside the dead zone of alpha,

The identification calculation unit is characterized in that the dead band width W and the gain ratio α are parameters to be identified together with the hull parameters relating to the hull motion model.

  According to the embodiment of the present invention, it is possible to further reduce the influence of the dead zone of the nozzle in the water jet propulsion ship and suppress the fluctuation of the nozzle.

1 is a block diagram illustrating a system including an automatic marine steering apparatus according to an embodiment. It is a block diagram which shows the structure of an identification calculating part. It is explanatory drawing which shows the coordinate system used with a route control system. It is a figure which shows a dead zone characteristic. It is a figure which shows the normalized nozzle model. Correction of figure: Horizontal axis δ-> δc It is a figure which shows the influence of an identification value error. It is a figure which shows the analysis result of an identification value error. It is a figure which shows a hull model. It is a figure which shows the recording time of the data used for parameter identification. It is a flowchart which shows operation | movement of an identification process. It is a figure which shows an identification value error. It is a figure which shows the time series response of the identification result in case error coefficient (epsilon) = 0.5. It is a figure which shows the time series response of the identification result in case of error coefficient (epsilon) =-0.1. It is a figure which shows the simulation result of the parameter identification corresponding to an installation state. It is a figure which shows the simulation result of the first parameter identification corresponding to a normal state. It is a figure which shows the simulation result of the parameter identification after the update corresponding to a normal state.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1. Automatic Ship Steering Device 1.1 Overall Configuration First, a system including an automatic ship steering device according to the present invention will be described. FIG. 1 is a block diagram illustrating a system including the marine vessel automatic steering apparatus according to the embodiment.

  As shown in FIG. 1, the system in the present embodiment includes a marine automatic steering apparatus 1 and a water jet propulsion ship 2 that is a control target thereof. Here, the water jet propulsion ship 2 is a combination of a water jet propulsion device 21, a hull 22 and sensors 23 each having a starboard nozzle 21a and a port nozzle 21b whose nozzle angles are changed by corresponding actuators.

The water jet propulsion device 21 can be switched between a normal state corresponding to the dead zone and an equipment state for specifying the dead zone. Each of the starboard nozzle 21a and the port nozzle 21b is tilted outward in a normal state so that the operation position thereof becomes a square shape by a nozzle offset _δDZ which is a correction angle corresponding to the dead zone. Thus, the dead zone is equivalently offset. Further, the starboard nozzle 21a and the port nozzle 21b are in a state in which the nozzle offset _δDZ is not applied to their operating positions in the equipped state.

  The sensors 23 also include a speed log that detects the surge speed u of the hull 22, a gyrocompass that detects the heading ψ of the hull 22, and a hull position (x, y) from a satellite positioning system (GNSS) such as GPS. Includes GNSS sensor to detect. It is assumed that the heading azimuth ψ, the surge speed u, and the hull position (x, y) detected by the sensors 23 are input to the identification calculation unit 12 of the boat automatic steering apparatus 1. Here, the hull position (x, y) is a hull position in a local horizontal coordinate system to be described later, and x and y indicate hull positions in the north direction and the east direction, respectively.

The marine vessel automatic steering apparatus 1 includes a trajectory calculation unit 11, an identification calculation unit 12, a subtractor 13, a feedback controller 14, a feedforward controller 15, and adders 16, 17a and 17b. Trajectory calculation unit 11 inputs the preset course [psi _S, is intended for calculating the reference azimuth [psi _R based on the trajectory plan from preset course [psi _S. The identification calculation unit 12 identifies the hull parameters and outputs the identified hull parameters to the trajectory calculation unit 11, the feedback controller 14, and the feedforward controller 15. The subtracter 13 outputs the difference e between heading [psi reference azimuth [psi _R and hull 22 that is output from the track calculation unit 11. The feedback controller 14 multiplies the deviation e output from the subtractor 13 by the control gain and outputs a feedback steering angle δ _FB . Feedforward controller 15 outputs the feed-forward steering angle [delta] _FF based on the reference orientation [psi _R output by the trajectory calculation unit 11. The adder 16 outputs a feedback steering angle [delta] _FB output by the feedback controller 14, a command steering angle [delta] _C by adding the output feedforward steering angle [delta] _FF by the feedforward controller 15. The adder 17a outputs an instruction steering angle [delta] _C, the positive nozzle offset + [delta] command steering angle [delta] _cS obtained by adding the _DZ to starboard nozzle 21a. The adder 17b outputs the command steering angle [delta] _C, a command steering angle [delta] _cP obtained by adding the negative of the nozzle offset - [delta _DZ to port nozzle 21b.

1.2 Identification Calculation Unit The configuration of the identification calculation unit will be described. FIG. 2 is a block diagram illustrating a configuration of the identification calculation unit.

As shown in FIG. 2, the identification calculation unit 12 includes an output data storage unit 121, an input data storage unit 122, an identification model 123, a subtractor 124, and a parameter adjustment unit 125. The output data storage unit 121 stores the heading ψ and the hull position (x, y) of the hull 22 as output data. The input data storage unit 122 stores the command steering angle δ _C output from the adder 16, the surge speed u detected by the sensors 23 and the heading ψ as input data. Note that both the output data storage unit 121 and the input data storage unit 122 can be ring buffer memories. The identification model 123 includes a hull model, an initial value, and an offset component, and inputs a command rudder angle δ _C , a bow direction ψ, and a surge speed u as input data stored in the input data storage unit 122, and model output data Model heading and model hull position are output. The subtractor 124 calculates an identification error that is a difference between the model output data output from the identification model 123 and the output data stored in the output data storage unit 121. The parameter adjustment unit 125 adjusts parameters constituting the identification model 123 based on the identification error calculated by the subtractor 124. The adjustment of this parameter will be described later in detail.

1.3 Route coordinate system The route coordinate system will be explained. FIG. 3 is an explanatory diagram showing a coordinate system used in the route control system.

As shown in FIG. 3, the coordinate system used in route control system consists local horizontal coordinate system O-XY and the body coordinate system O _B -X _B Y _B, both of which are right-handed three-axis orthogonal coordinate system. In the coordinate system, the Z-axis is positive in the direction of gravity, and the rotation polarity is positive in the right-hand screw direction. Since the coordinate system uses two dimensions, the X axis and the Y axis, the Z axis is omitted in FIG. Also, local horizontal coordinate system of the X-axis is taken up north, the body coordinate system taking the X _B axis heading. In FIG. 3, u represents a surge speed, v represents a sway speed, r represents a turning angular speed, and ψ represents a bow direction.

2 Hull Motion Model The hull motion model (hull model) of the water jet propulsion ship and the dead zone correction method will be described. As will be described later, the hull model is composed of a nozzle model, a yaw motion, and a hull model relating to the sway motion. The nozzle model is a pair of water jets and has a dead zone (DZ: Dead-Zone).

2.1 Nozzle model The nozzle model will be described. FIG. 4 is a diagram illustrating the dead zone characteristics. FIG. 5 is a diagram illustrating a normalized nozzle model. In FIG. 4, the vertical axis represents the yaw angular velocity, the horizontal axis represents the command steering angle, and in FIG. 5, the vertical axis represents the output angle based on the nozzle model, and the horizontal axis represents the command steering angle.

  The starboard nozzle 21a and the port nozzle 21b have the same dead zone characteristics. In the nozzle model, as shown in FIG. 4, it is assumed that the dead zone characteristic is a point object, the dead zone appears in the gain of the yaw angular velocity and the sway velocity, and the response of the nozzle is sufficiently faster than the response of the hull motion. Expressing a pair of nozzles as the sum of a single nozzle,

become. Here, δ is a virtual rudder angle, which corresponds to the rudder angle of the normal rudder, the subscript _S is the starboard direction Starboard, the subscript _P is the port direction Port, and δ _noz is the output angle of the nozzle model. As shown in FIG. 5, this δ _noz is obtained by using a command steering angle δ _c .

It is determined. Here, W represents the width of one side of the dead zone, and α represents the gain ratio of the dead zone when the outside of the dead zone is 1.

2.2 Influence of dead zone correction This section explains how to deal with the dead zone using the automatic steering system for ships. FIG. 6 is a diagram illustrating the influence of the dead band offset. FIG. 7 is a diagram illustrating the analysis result of the identification value error.

Since the dead zone is generated due to the mechanism of the water jet propulsion device 21, it is difficult to remove the dead zone by the control signal. Therefore, by giving the dead zone offset δ _DZ to the command rudder angle δ _c that is an input to the nozzle and changing the operating condition of the nozzle angle, the dead zone can be apparently canceled out equivalently. In the formulas (1) and (2), a command rudder angle and a positive nozzle offset are added to the starboard nozzle 21a, and a negative nozzle offset is added to the command rudder angle of the port nozzle 21b. Add error to nozzle offset,

far. Here, the subscript ^ is an identification value, ΔW is an error, ε is an error coefficient, and Equation (3) corresponds to a case where there is an error in the identification value of the dead zone. At this time, if the nozzle offset is substituted into the equations (1) and (2), the steering angle is

Is obtained as follows. The above formula is schematically shown in FIG. From the above equation and FIG. 6, ΔW affects the horizontal axis δ _c and the horizontal axis δ. Compared to the case of ΔW = 0, when ΔW> 0, no dead zone is generated, and the linear region is 2 W and does not change. Further, when ΔW <0, a dead zone is generated, and the linear region becomes 2W−2 | ΔW | and becomes narrower. Here, the linear region indicates a range of 2 W when ΔW = 0. Accordingly, the nozzle offset is δ _DZ ≧ W. However, attention must be paid to the thrust drop due to δ _DZ > W. In FIG. 7 where W = 4 deg and α = 0.1, when δ _DZ = W and ΔW = 0, the dead zone is canceled out in a range twice as large as the dead zone, the influence of αW does not appear, and the slope is 0.5 (1 + α).

2.3 Hull movement model The hull movement model (hull model) is explained below. FIG. 8 is a diagram showing a hull model.

As shown in FIG. 8, the hull model includes a nozzle model and a hull model related to yaw motion and sway motion.
The hull models related to the yaw motion and the sway motion of the water jet propulsion ship 2 are respectively

become. Here, s is a Laplace operator, r and R (s) are turning angular velocities, v and V (s) are transverse flow velocities, ψ and Ψ (s) are bow headings, and δ and Δ (s) are steering angles. ,

It is. Here _{K r} is swirling force gain, _{K v} represents the cross flow _{gain, T r, T r3, T} v during each constant. Further, the subscript _r indicates that it relates to a turning motion, and the subscript _v indicates that it relates to a lateral flow (sway) motion. In the present embodiment, a stable ship is a control target.

3 Control action 3.1 Hull parameters The control system using the automatic steering system for ships does not include the nonlinear terms due to the dead zones of (1) and (2), and is designed based on the linear model of (9) and (10). Is done. At this time, there is a situation in which the influence of the nonlinear term cannot be ignored. In order to avoid such a situation, a nozzle offset is used. As described above, in the dead zone, the linear range of the command rudder angle is 2 W, and the gain slope is about half of the gain slope outside the dead zone. The control gain is calculated from the hull parameters in consideration of the consideration. The hull parameters are set as follows.

The water jet propulsion device 21 can be switched from the equipped state to the normal state. Before the identification, the initial value (subscript ₀ ) is

Set to When the water jet propulsion device 21 is in the equipped state, the identification value (subscript ^) is

Set to When the water jet propulsion device 21 is in a normal state, the identification value is

Set to

Before identification is K _r becomes smaller dead zone, stability if instability occurs due to excessive attenuation of the differential gain is maintained. In the equipped state, the hull parameters in the normal state are assumed and set in advance. In the normal state, the dead zone characteristic is not identified, so the hull parameter identification value is updated.

3.2 Parameter Identification Parameter identification of the hull model is performed by the identification calculation unit 12, specifically, the parameter adjustment unit 125. The identification model 123 is composed of the nozzle model, the hull model related to the yaw motion, and the hull model related to the sway motion described above. The dead band one-sided width W as the dead band characteristic and the dead band gain ratio α are estimated from the yaw identification in the equipped state. The identification values W ^ and α ^ are used as known in the yaw identification and the sway identification in the normal state.

3.2.1 Identification Model The yaw identification model is composed of a nozzle model of equations (1) and (2) and a yaw motion model of equation (9). That is,

It is determined. Here, _δro indicates a steering angle offset caused by wind power. The parameters identified by this are as follows.

Where X _RDZ represents the parameters identified in armed state, X _r is identified value W in the normal state ^ is a parameter which is identified using alpha ^.

  As described above, the equipment state and the normal state have the same identification model but different identification parameters. The sway identification model is composed of the sway model with the steering angle δ from the nozzle model using W ^, α ^ as input. That is,

It is determined. Here, W ^, alpha ^ identification value from the yaw identification, x, y, respectively, north, east direction of the hull position, [psi ^- represents a detection direction, [delta] _vo is local horizontal coordinate caused by the tide Indicates the velocity offset component of the system. Therefore, the parameters to be identified are as follows:

3.2.2 Identification calculation The identification calculation will be described. FIG. 9 is a diagram showing the recording time of data used for parameter identification. In FIG. 9, (a) shows the data recording time in the equipment state, and (b) shows the data recording time in the normal state.

  The data sampling time by the identification calculation unit 12 is set to 0.4 seconds in consideration of the fast hull movement of the water jet propelling line, and the recorded data accumulated in the output data storage unit 121 and the input data storage unit 122 are As shown in FIG. 9A, the time series of the left and right side changing needles in the equipped state and the one side changing needle (current) in the normal state is obtained. In addition, the identification calculation unit 12 estimates the dead zone characteristics (W, α) and the hull parameters in the equipped state, and estimates the hull parameters in the normal state. The initial values and limit values of the parameters are shown in Table 1 below.

In Table 1, a lower limit value and an upper limit value are shown as limit values, and there are two initial values of T _r and K _r / T _r , respectively. The identification calculation unit 12 performs identification calculation 2 × 2 = 4 times for each initial value, and selects an identification value that minimizes the evaluation amount (described later).

3.2.3 Identification processing The parameter identification processing will be described. FIG. 10 is a flowchart showing the operation of the identification process.

  The parameter adjustment unit 125 performs yaw identification based on time-series data at the time of a needle change response in each of the equipment state and the normal state. Further, the parameter adjustment unit 125 performs the sway identification based on the identification value (W ^, α ^) identified in the yaw identification and the time series data.

  Here, an identification process for performing yaw identification and sway identification will be described. This identification process is performed in substantially the same procedure for the yaw identification in the equipment state and the normal state, and the sway identification in the normal state. It shall be required. First, the output data storage unit 121 and the input data storage unit 122 store output data and input data, respectively, as time series data at the time of changing the needle (S101). Here, the output data are the heading and hull position detected by the sensors 23, the heading is used for yaw identification, and the hull position is used for sway identification. Further, in the yaw identification, the input data is a command rudder angle, and in the sway identification, the input data is a command rudder angle, a heading, and a surge speed. After changing the course, calculation conditions and input data are given to the identification model 123, and model output data is output (S102). Here, the model output data is the heading in the yaw identification, and the hull position in the sway identification. After the model output data is output, the parameter adjustment unit 125 calculates an evaluation amount, which is a sum of squares of errors (identification errors) between the output data calculated by the subtractor 124 and the model output data, for each parameter a plurality of times. For example, as described above, the calculation is performed four times (S103), and the parameter having the minimum evaluation amount is output as the identification value (S104).

4). Verification The verification effect of the identification model described above is verified by simulation. The following table shows the hull parameters to be controlled and the initial values of the control parameters in this simulation. In the simulation, the number of calculations is twice, the identification value is updated twice, the initial orientation is 40 degrees, and the amount of change is 10 degrees.

4.1 Effect of dead band correction The effect on error coefficient ε in equation (3) is verified. FIG. 11 is a diagram illustrating the identification value error. FIG. 12 is a diagram showing a time-series response of the identification result when the error coefficient ε = 0.5. FIG. 13 is a diagram showing a time-series response of the identification result when the error coefficient ε = −0.1. Note that disturbance components are not included in these drawings.

According to FIG. 11, ΔW> 0 has a smaller error than ΔW <0, and the errors of K _r and K _v are smaller than the errors of T _r and T _r3 . Therefore, these are the effects of the presence or absence of the dead zone, and it can be seen that T _r and T _r3 are easily affected by the response. Also, according to FIGS. 12 and 13, ΔW> 0 (FIG. 12) has better responsiveness and identification than ΔW <0 (FIG. 13). It can be seen that the limit is about -0.1.

  Thus, when the identification value error is ΔW ≧ 0, the time-series response is good. According to the identification by the identification calculation unit 12 described above, a true value cannot be obtained when ΔW ≠ 0. However, since the parameter including ΔW is identified, the influence of the identification error shown in FIG. 11 is small. Therefore, the dead zone countermeasure can be expected to be effective when ΔW ≧ 0.

4.2 Time-series response Explain the response results for equipment and normal conditions. FIG. 14 is a diagram illustrating a simulation result of parameter identification corresponding to the equipment state. FIG. 15 is a diagram illustrating a simulation result of initial parameter identification corresponding to a normal state. FIG. 16 is a diagram illustrating a simulation result of the parameter identification after the update corresponding to the normal state. In each of FIGS. 14 to 16, (a) shows a case without a disturbance component, and (b) shows a case with a disturbance component.

  In this simulation, the disturbance component includes a wave disturbance with an amplitude of 1 deg, a period of 10 seconds, a sine input, a steering angle offset of 1 deg, and a tidal component with a northward direction of 5 kn. It shall be updated by the equation (12). The identification value results in the equipment state and the normal state are shown in Tables 3 and 4 below.

From Table 3, it can be seen that the parameters are appropriately identified regardless of the presence or absence of disturbance. Further, it can be seen from Table 4 that parameters are appropriately identified when δ _DZ = W ^ regardless of the presence or absence of disturbance.

  14 to 16, the azimuth of the object to be controlled has a characteristic of a dead zone, and the azimuth response has a gradual change with a command steering angle of ± 4 degrees as a boundary. The simulation result shown in FIG. 14 corresponds to Table 3, and it can be seen from FIG. 14 that the identification error is almost zero. Therefore, the values in Table 3 are appropriate. The simulation results shown in FIGS. 15 and 16 correspond to Table 4. It can be seen from FIG. 15 that shows the first identification result that identification is not possible, and it can be seen from FIG. 16 that shows the updated identification result that the values in Table 4 are appropriate.

  The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Automatic steering device 2 for ships Water jet propulsion ship 12 Identification calculating part 21 Water jet propulsion machine 21a Starboard nozzle 21b Port nozzle 22 Hull 123 Identification model 125 Parameter adjustment part

Claims (3)

An automatic steering device for a ship that outputs a command rudder angle using a hull parameter based on a reference direction and a heading direction for a water jet propulsion ship including a water jet propulsion device having at least a pair of nozzles,
An identification calculation unit for identifying the hull parameters;
The identification calculation unit
An identification model that outputs model output data from predetermined input data obtained by the marine vessel automatic steering device;
A parameter adjustment unit that adjusts and identifies the hull parameters from a comparison result between model output data from the identification model and output data that is actual measurement values relating to the hull;
The identification model includes a nozzle model and a hull motion model. The nozzle model includes δ as an output rudder angle, δ _c as a command rudder angle, δ _DZ as a nozzle offset, W as one side width of the dead zone of the pair of nozzles, α is the gain ratio of the dead zone to the gain outside the dead zone,
Represented by
The automatic steering apparatus for a ship, wherein the identification calculation unit uses the dead zone width W and the gain ratio α as parameters to be identified together with a hull parameter relating to the hull motion model. The water jet propulsion device switches the operation position of the pair of nozzles between a normal state in which the nozzle offset δ _DZ corresponding to the dead zone width W is inclined outward and an installation state in which the nozzle offset δ _DZ is not applied. Is possible,
The identification calculation unit, after identifying the dead zone width W and the gain ratio α together with the hull parameters in the equipped state, sets only the hull parameters to be identified in the normal state. The marine vessel automatic steering apparatus according to claim 1. The identification model includes a yaw identification model including the nozzle model and a yaw motion model, and a sway identification model including the nozzle model and a sway motion model,
The identification calculation unit estimates the dead band width W and the gain ratio α together with the hull parameters relating to the yaw identification model in the identification by the yaw identification model, and the estimated dead band width W ^ in the identification by the sway identification model 3. The ship automatic steering apparatus according to claim 2, wherein the ship parameter relating to the sway identification model is estimated with the gain ratio α ^ known.