JP2011189884A - Automatic steering device, automatic steering method, and automatic steering program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic steering device capable of altering various parameters immediately in response to a dynamic characteristic change of a hull. <P>SOLUTION: Disclosed is the automatic steering device 1 so constituted that a command steering angle signal U<SB>c</SB>is outputted thereto so as to have the bow azimuth ϕ matched with a preset course ϕ<SB>c</SB>. The automatic steering device 1 comprises a Froude number calculation section 6 and a steering angle control section 7. The Froude number calculation section 6 computes out a Froude number Fr from a hull velocity V and a hull length L. The steering angle control section 7 determines control parameters based on the Froude number Fr and determines the command steering angle signal U<SB>c</SB>based on the control parameters. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention mainly relates to an automatic steering apparatus. Specifically, the present invention relates to a configuration for identifying a control parameter in an automatic steering apparatus.

  In general ships, it takes a certain amount of time until the hull starts turning after steering. Further, once the hull starts turning, the turning continues for a while after the rudder is returned to the neutral position. Therefore, the rudder needs to be returned early in order to take a desired course. Thus, there is a unique difficulty in steering a ship, and considerable skill is required to perform the operation of turning the bow in a desired direction reliably and quickly. Further, since there is an influence of disturbances such as waves and winds on the ocean, it is necessary to perform steering so as to cancel the disturbances in order to advance the hull straight. However, because of the difficulty of steering as described above, even if the ship is simply moved straight, a considerable concentration is required, which is a burden on the steering person.

  The marine vessel automatic steering device (autopilot) is mounted on a marine vessel in order to reduce the burden on the steering person as described above. A general automatic steering device is configured to input a heading (setting course) to which the bow should be directed as a target value. By operating a steering machine as an operation element, the steering angle is automatically changed. Then, control is performed so that the heading as a control amount coincides with the set course. This control can be performed by a known control method such as feedforward control or feedback control.

  By the way, in order to properly operate the steering machine in the automatic steering apparatus as described above, various control parameters need to be appropriately set. However, the kinematic characteristics of the ship vary greatly depending on the ship speed and the load situation. Therefore, if the control parameter is set to a fixed value, a situation where appropriate control cannot be performed may occur. In view of this, a so-called adaptive automatic steering device has been proposed which is configured to automatically change the control parameter in accordance with the situation.

  Such an automatic steering device is described in Patent Document 1, for example. Patent Document 1 discloses a configuration including an identification calculation unit that calculates a parameter that determines the characteristics of a ship based on a deviation of a heading with respect to a reference course. According to Patent Literature 1, it is possible to realize an optimum course changing course considering the characteristics of the ship.

Japanese Patent Laid-Open No. 9-207889

  However, in the configuration of Patent Document 1, in order to calculate the estimated values of the turning force index and the tracking stability index, the deviation values at the start and end of the shift mode, which is one period during the course change, are required. . Therefore, in the configuration of Patent Document 1, even if the motion characteristics of the hull change dynamically during the course of keeping the hand, new parameters cannot be calculated until the next course change operation. Further, in the configuration of Patent Document 1, the turning force index cannot be accurately obtained until a sufficiently long time has elapsed in the constant speed mode even at the time of changing the needle. Therefore, in the configuration of Patent Document 1, it is considered that when the motion characteristic of the hull changes dynamically, the change cannot be immediately reflected on various parameters.

  Further, Patent Document 1 discloses that estimated parameters (a turning index and a tracking stability index) are fed back to a feedback controller, and an appropriate gain or constant determined using the estimated parameters is given. However, since these gains or constants are also obtained using the estimated parameters, when the motion characteristics of the hull change dynamically, the changes cannot be immediately reflected on the gains or constants.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide an automatic steering device that can immediately change various parameters in accordance with a dynamic characteristic change of a hull. .

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to a first aspect of the present invention, there is provided an automatic steering device that outputs a command rudder angle with respect to a steering machine so that a heading coincides with a set course, and has the following configuration. That is, the automatic steering apparatus includes a fluid number calculation unit and a steering angle control unit. The fluid number calculation unit calculates the fluid number from the ship speed and the hull length. The rudder angle control unit determines a control parameter based on the fluid number, and determines the command rudder angle based on the control parameter.

  Thus, by determining the control parameter based on the number of fluids, it is possible to obtain a control parameter suitable for the state of the hull. Further, since the fluid number can be immediately calculated from the ship speed and the hull length, a control parameter corresponding to the change in the situation can be obtained immediately. Furthermore, since the number of fluids is a number obtained by making the ship speed dimensionless using the hull length, it is considered that ships with the same fluid number have similar motion characteristics even if the size of the hull is different. it can. Therefore, by determining the control parameter using the Froude number, it is possible to output an appropriate command steering angle for any size hull.

  In the automatic steering apparatus, it is preferable that the rudder angle control unit includes a feedforward control unit that performs feedforward control at the time of needle change and a feedback control unit that performs feedback control at the time of needle holding.

  That is, by performing feedforward control at the time of changing the needle, it is possible to improve the responsiveness of changing the steering angle at the time of changing the needle. Further, by performing feedback control during the course of keeping the needle, it is possible to stabilize the course and improve the straightness of the hull.

  The automatic steering device is preferably configured as follows. That is, the steering angle control unit includes a feedforward control unit, a reference course determination unit, and a feedforward control parameter determination unit. The feedforward control unit performs feedforward control at the time of a change of needle. The reference course determining unit determines a reference course based on the set course after the course change and the fluid number. The feedforward control parameter determination unit determines a turning index and a tracking index based on the fluid number. The feedforward control unit performs the feedforward control based on the reference course, the turnability index, and the followability index.

  Thus, by determining each parameter (reference course, turning index and followability index) based on the Froude number, it is possible to appropriately perform a turning operation according to the state of the hull.

  The automatic steering device is preferably configured as follows. That is, the rudder angle control unit includes a feedback control unit, a PID control parameter determination unit, and a PID control parameter correction unit. The feedback control unit performs PID control when the needle is held. The control parameter determining unit for PID control determines a control parameter for PID control based on the fluid number. The control parameter correction unit for PID control determines a correction parameter for PID control based on the turning angular velocity of the hull and the fluid number. The feedback control unit performs the PID control using the PID control parameter corrected by the correction parameter.

  That is, since PID control is particularly effective as control for matching a control value that varies due to disturbance to a target value, it is preferable to use it for control during needle holding as described above. Further, by determining the PID control parameter based on the fluid number, PID control suitable for the situation of the ship can be performed. Further, by calculating a correction parameter for PID control based on the turning angular velocity, it is possible to appropriately suppress disturbance due to, for example, waves or winds.

  According to a second aspect of the present invention, there is provided an automatic steering program for outputting a command rudder angle for a steering machine so that the heading coincides with a set course, and causes the automatic steering apparatus to execute processing including the following steps: An automatic steering program is provided. That is, the automatic steering program includes a fluid number calculation step and a steering angle control step. In the fluid number calculation step, the fluid number is calculated from the ship speed and the hull length. In the steering angle control step, a control parameter is determined based on the fluid number, and the command steering angle is determined based on the control parameter.

  Thus, by determining the control parameter based on the number of fluids, it is possible to obtain a control parameter suitable for the state of the hull. Further, since the fluid number can be immediately calculated from the ship speed and the hull length, a control parameter corresponding to the change in the situation can be obtained immediately. Furthermore, since the number of fluids is a number obtained by making the ship speed dimensionless using the hull length, it is considered that ships with the same fluid number have similar motion characteristics even if the size of the hull is different. it can. Therefore, by determining the control parameter using the Froude number, it is possible to output an appropriate command steering angle for any size hull.

  According to a third aspect of the present invention, there is provided an automatic steering method for outputting a command rudder angle with respect to a steering machine so that a heading coincides with a set course, which includes the following steps. That is, this automatic steering method includes a fluid number calculation step and a rudder angle control step. In the fluid number calculation step, the fluid number is calculated from the ship speed and the hull length. In the rudder angle control step, a control parameter is determined based on the fluid number, and the command rudder angle is determined based on the control parameter.

  Thus, by determining the control parameter based on the number of fluids, it is possible to obtain a control parameter suitable for the state of the hull. Further, since the fluid number can be immediately calculated from the ship speed and the hull length, a control parameter corresponding to the change in the situation can be obtained immediately. Furthermore, since the number of fluids is a number obtained by making the ship speed dimensionless using the hull length, it is considered that ships with the same fluid number have similar motion characteristics even if the size of the hull is different. it can. Therefore, by determining the control parameter using the Froude number, it is possible to output an appropriate command steering angle for any size hull.

The block diagram which shows the structure of the automatic steering system which concerns on one Embodiment of this invention. The block diagram which shows the structure of an automatic steering apparatus. The figure explaining a reference course. The block diagram which shows the detailed structure of an automatic steering apparatus. The figure explaining the difference between a planing type ship and a drainage type ship.

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

  FIG. 1 shows an automatic steering system using a marine vessel automatic steering apparatus according to an embodiment of the present invention. This automatic steering system includes an automatic steering device 1, a steering machine 2, a hull 3, and a direction sensor 4. The automatic steering device 1, the steering machine 2, and the direction sensor 4 are mounted on the hull 3.

  The azimuth sensor 4 is configured to detect the bow azimuth φ of the hull 3 and output it to the automatic steering device 1.

The automatic steering device 1 is configured so that the steering wheel can input a set course φ _c (direction in which the hull should travel). Then, the automatic steering device 1 instructs the steering angle signal (command steering angle) U _c to specify the steering angle U of the steering machine 2 so that the heading φ as the control amount coincides with the set course φ _c as the target value. Is output.

Steering engine 2 is configured to change the steering angle U in response to a command steering angle signal U _c. By appropriately adjusting the rudder angle U, the heading azimuth φ of the navigating hull 3 can be controlled.

With the above configuration, the heading azimuth φ of the hull 3 can be controlled to coincide with the set course φ _c .

  Next, the configuration of the automatic steering device 1 will be described in detail.

  The automatic steering apparatus 1 according to the present embodiment includes hardware (not shown) such as a CPU, a ROM, and a RAM, and software such as an automatic steering program stored in the ROM.

  The automatic steering program is for realizing the automatic steering method according to the present invention by the automatic steering apparatus 1. This automatic steering method includes a reference course determination step, a fluid number calculation step, and a rudder angle control step.

  Therefore, the automatic steering program for realizing the automatic steering method includes a reference course determining step, a fluid number calculating step, and a rudder angle control step in correspondence with the respective steps. Then, when the hardware and software operate in cooperation, the automatic steering device 1 can function as the reference course determination unit 5, the fluid number calculation unit 6, the steering angle control unit 7, and the like.

  Next, the functional configuration of the automatic steering apparatus 1 will be described with reference to FIG.

The set course φ _c set by the steering person is input to the reference course determining unit 5. Referring course determination unit 5, based on the preset course phi _c input, it is configured to determine a reference course r. The processing content in the reference course determining unit 5 corresponds to the reference course determining step of the automatic steering program.

Hereinafter, the reference course r will be described. As an example, it is set to preset course phi _c is phi _c0, consider the case where heading phi of the hull is consistent with phi _c0 (if the hull is straight toward the azimuth phi _c0). In this state, it is assumed that the steering wheel changes the set course to φ _c1 . In this case, the automatic steering device 1 must perform control so that the heading φ quickly becomes φ _c1 . However, just because the _steerer 2 is operated rapidly, the heading φ cannot be changed immediately from φ _c0 to φ _c1 , and the hull 3 turns over a certain amount of time. . Therefore, even if the rudder angle U is increased unnecessarily, the energy loss increases and is not rational. Rather, it is preferable to operate so that the rudder angle U is gradually increased or decreased over a certain amount of time in accordance with the movement of the hull 3 turning over time. In addition, since inertia acts on the hull 3 that has started to turn, just because the rudder angle U is suddenly returned to zero (neutral position), the turning does not stop immediately. Therefore, it is preferable to start the operation of returning the rudder angle U to zero before the heading φ reaches the target value _φc1 . To realize such an operation in a feed forward control (described later), it become necessary reference course r referred to when determining the command steering angle signal U _c.

Therefore, the reference course determining unit 5 is configured to calculate a reference course r that changes with a turning angular velocity and a turning angular acceleration that can be followed by the hull 3 when the set course φ _c is changed. For example, when the set course is changed from φ _c0 to φ _c1 as described above, the reference course r output from the reference course determining unit 5 is temporally from φ _c0 to φ _{c1 as} shown in the graph of FIG. It changes smoothly continuously. As described above, the reference course determining unit 5 is configured as a kind of low-pass filter. Thus, by determining the command steering angle signal U _c based on the reference course r that changes smoothly with time, the steering machine 2 can be operated so that the steering angle U changes smoothly.

As will be described in detail later, the automatic steering device 1 of the present embodiment is not the value of the reference course r itself but the turning angular velocity r ′ of the reference course r (first derivative with respect to the time of the reference course r) in the course changing mode. And the turning angle acceleration r ″ of the reference course (second derivative with respect to the time of the reference course r) to determine the command steering angle signal U _c . The turning angular velocity r ′ of the reference course r and the turning angular acceleration r ″ of the reference course r are calculated at any time. The turning angle velocity r ′ of the reference course and the turning angle acceleration r ″ of the reference course are input to the steering angle control unit 7.

The reference course r is input to the deflection angle calculation unit 8. The heading azimuth φ output from the azimuth sensor 4 is input to the declination calculator 8. The deflection angle calculation unit 8 is configured to calculate a difference (a deflection angle φ _err ) between the reference course r and the heading azimuth φ and output the difference to the steering angle control unit 7.

The rudder angle control unit 7 makes the deviation angle φ _err zero based on the turning angle velocity r ′ of the reference course, the turning angle acceleration r ″ of the reference course, and the deviation angle φ _err (the heading direction φ is changed to the reference course). The command steering angle signal U _c for the steering device 2 is output so that the heading azimuth φ coincides with the set course φ _c , that is, the hull 3. The steering angle control unit 7 corresponds to the steering angle control step of the automatic steering program.The processing in the steering angle control unit 7 Details of this will be described later.

The fluid number calculation unit 6 is configured to calculate the fluid number Fr based on the hull length L and the current ship speed V. The hull length L is input to the automatic steering device 1 by the user in advance. Further, the hull 3 includes a ship speed measuring unit 9 that can detect the ship speed V in real time, and the fluid number calculation unit 6 calculates the fluid number Fr as needed using the ship speed V that changes in real time. Output. The Froude number Fr is a numerical value representing the ratio of inertial force to gravity in the fluid, and is defined by the following equation.
Fr = V / (gL) ^1/2
Here, g is a gravitational acceleration.

  The fluid number Fr is output to the reference course determining unit 5 and the steering angle control unit 7. The role of the fluid number Fr will be described in detail later. The processing content in the fluid number calculation unit 6 corresponds to the fluid number calculation step of the automatic steering program.

  Next, the configuration of the automatic steering device 1 will be described in more detail with reference to FIG.

  First, the reference course determining unit 5 will be described in more detail. As described above, the reference course determining unit 5 is configured as a kind of low-pass filter. Specifically, the reference course determining unit 5 includes a filter calculating unit 11 and a filter constant determining unit 12 that determines a filter constant to be used for calculation in the filter calculating unit 11.

The filter operation unit 11 receives the set course φ _c set by the steering wheel and the filter constant determined by the filter constant determination unit 12. The filter calculation unit 11 performs a low-pass filter process using the filter constant on the input setting course φ _c to calculate the latest reference course r. In addition, the filter calculation unit 11 calculates the latest turning angular velocity r ′ of the reference course and the latest turning angular acceleration r ″ of the reference course using the latest reference course r and the reference course calculated in the past. And output to the rudder angle control unit 7.

  By the way, the ship generally has a property that the rudder is more effective as the ship speed V increases. Further, in general, the rudder is more effective as the hull length L is shorter. That is, in general, it can be said that the rudder is more effective as the Froude number Fn is larger. On the other hand, since the ship speed V changes at any time during navigation, the ease of rudder effectiveness changes dynamically. Here, since the reference course r should be calculated in consideration of the difficulty (or ease) of the rudder of the hull, the difficulty (or ease) of the rudder changes. It is preferable to change the filter constant accordingly.

  Therefore, the filter constant determination unit 12 is configured to determine the filter constant based on the fluid number Fr. Specifically, the filter constant determination unit 12 increases the absolute value of the turning angular velocity r ′ of the reference course so that the graph of FIG. 3 suddenly rises as the Froude number Fr increases (the rudder becomes more effective). To determine the filter constant. On the contrary, the filter constant determination unit 12 decreases the absolute value of the turning angular velocity r ′ of the reference course so that the graph of FIG. 3 rises more gently as the Froude number Fr is smaller (the rudder is less effective). ) Determine the filter constant. Since the reference course r is obtained based on the filter constant determined in this way, it can be said that the reference course determination unit 5 obtains the reference course r based on the fluid number Fr.

  Thus, the reference course r can be changed quickly when the rudder is effective, and the reference course r can be changed slowly when the rudder is difficult to work. That is, by obtaining the control parameter (reference course r in the above example) using the Froude number Fr, it is possible to calculate a parameter suitable for the actual motion characteristics of the hull.

  Further, since the ship speed V and the fluid number Fr are in a simple proportional relationship, when the ship speed V changes, the fluid number Fr can be obtained immediately. By configuring the control parameter (in the above example, the filter constant) using this fluid number Fr, it is possible to immediately determine a parameter corresponding to the change in the motion characteristics of the hull 3. .

  As a method for determining the filter constant from the Froude number Fr, the relationship between the Froude number Fr and the filter constant is stored in a table, and the filter constant corresponding to the Froude number Fr is read from the table. Can do. In this case, for example, an experiment such as measuring the motion characteristics of the hull while changing the Froude number Fr may be performed, and the relationship between the optimum filter constant and the Froude number may be stored in advance as a table.

  By the way, even if the ship speed V is the same, if the size or the like of the hull is different, the motion characteristics are greatly different. Therefore, it is ideal to prepare the table for determining the filter constant individually for each hull. . However, in practice, it is very troublesome to create the above table by conducting an experiment for each hull, which is not practical. On the other hand, the Froude number Fr is a numerical value obtained by making the ship speed V non-dimensional using the hull length L. Therefore, ships with the same Froude number Fr have similar motion characteristics regardless of the size of the hull. Have. In other words, it is considered that ships with the same Froude number Fr can use the same filter coefficient regardless of the size of the hull.

  Therefore, if the filter constant is determined according to the Froude number Fr as in this embodiment, it is not necessary to prepare a table for determining the filter constant for each hull, and the optimum filter constant It is sufficient to prepare one table showing the relationship with the fluid number Fr. In this way, by configuring the control parameter (in the above example, the filter constant) to be determined based on the Froude number Fr, it is possible to greatly reduce the time and effort required when designing the automatic steering device 1. .

  Next, the steering angle control unit 7 will be described in detail. The steering angle control unit 7 includes a feedforward control unit 21, a feedforward control parameter determination unit 22, a feedforward steering angle correction unit 23, a PID control unit 24, a PID control parameter determination unit 25, and a PID. A control parameter correction unit 26 for control.

The rudder angle control unit 7 of the present embodiment is configured to vary the processing content between the needle changing mode and the needle holding mode. Note that the course changing mode is a mode for controlling the hull to turn. Specifically, as shown in FIG. 3, the needle changing mode starts when the set course φ _c is changed, and ends when the reference course r matches the newly set course. On the other hand, the needle-holding mode is a mode in which control is performed so as to keep the course of the hull straight. More specifically, as shown in FIG. 3, the period of the reference course r coincides with the preset course phi _c (periods other than veering mode) is Hohari mode.

  First, control in the needle changing mode will be described. In the needle changing mode, the rudder angle control unit 7 mainly performs feedforward control. That is, in the needle changing mode, since it is necessary to operate the steering machine 2 in accordance with the temporal change of the reference course r, it is preferable to perform feedforward control with excellent responsiveness.

  More specifically, the feedforward control unit 21, the feedforward control parameter determination unit 22, and the feedforward steering angle correction unit 23 function in the needle changing mode. On the other hand, in this needle changing mode, the PID control unit 24, the PID control parameter determination unit 25, and the PID control parameter correction unit 26 do not function.

The purpose of the feedforward control unit 21 is to change the rudder angle U of the steering machine 2 so as to match the bow direction φ with respect to the reference course r that changes with time, and to turn the hull 3. In the present embodiment, the steering angle U is determined using a so-called “Nomoto primary approximation model”. The Nomoto primary approximation model is a model that describes the relationship between the time change of the heading azimuth φ and the steering angle U, and is represented by the following equation.
U = (Tφ ″ + φ ′) / K

  Here, φ ′ is the turning angular velocity of the hull 3 (first derivative with respect to the time of the heading φ), φ ″ is the turning angular acceleration of the hull 3 (secondary derivative with respect to the time of the heading φ), and K is. The turnability index, T, is called the followability index.

The feedforward control unit 21 has an object of matching the heading φ with respect to the reference course r, and therefore, an equation for calculating the steering angle U is obtained by setting φ = r in the above equation. be able to.
U = (Tr ″ + r ′) / K

  The reference course turning angular velocity r ′ and the reference course turning angular acceleration r ″ used in the above formula are calculated by the reference course determination unit 5 and output to the steering angle control unit 7 as described above. Therefore, the feedforward control unit 21 can obtain the steering angle U by substituting these values into the above formula.

When calculating the steering angle U, feed-forward control unit 21 generates and outputs a feedforward command steering angle signal U _FF for realizing the steering angle U to the steering engine 2. Feedforward command steering angle signal U _FF, after being corrected by the feed-forward steering angle correction unit 23 will be described later, are output to the steering gear 2 from the steering angle control unit 7 as an instruction steering angle signal U _c.

  By the way, the turning index K and the following index T are values specific to the hull, and are obtained by a test using an actual hull (for example, a Z test). On the other hand, since the motion characteristics of the hull change with the ship speed V, the turning ability index K and the followability index T also change with the ship speed V. Therefore, if the turning ability index K and the following ability index T are fixed values, it is not possible to perform feedforward control adapted to the actual situation of the hull. Although a method for obtaining the turning index K and the tracking index T for each ship speed V by performing a Z test with various changes in the ship speed V is also conceivable, it is very troublesome.

  Therefore, the feedforward control parameter determination unit 22 determines the control parameters (the turning index K and the tracking index T) used for the feedforward control based on the fluid number Fr, and outputs them to the feedforward control unit 21. It is configured. Hereinafter, the feedforward control parameter determination unit 22 will be described.

It is known that the turning index K is approximately proportional to the ship speed V, and the followability index T is approximately inversely proportional to the ship speed V. Since the Froude number Fr is proportional to the ship speed V, it can be said that the turning index K is proportional to the Froude number Fr, and the followability index T is inversely proportional to the Froude number. Therefore, if the turning index K ₀ and the followability index T ₀ when the Froude number is Fr ₀ are obtained in advance by a Z test or the like, the turning ability index K and the followability index T when the Froude number is Fr are as follows. It can be calculated by the following formula.
K = K ₀ (Fr / Fr ₀ )
T = T ₀ (Fr ₀ / Fr)

  The feedforward control parameter determination unit 22 determines the turnability index K and the followability index T by substituting the fluid number Fr calculated by the fluid number calculation unit 6 into the above formula. The feedforward control unit 21 performs feedforward control based on the control parameter determined by the feedforward control parameter determination unit 22 as described above. Thereby, feedforward control suitable for the actual situation of the hull can be performed.

Next, the feedforward steering angle correction unit 23 will be described. In general, the feedforward control has a drawback that the amount of control (heading azimuth φ) deviates from the target value (reference course r) if there is a disturbance (wave, wind, etc.). Further, the feedforward control parameter determination unit 22 determines the control parameter according to the state of the hull from the fluid number Fr. However, since the load state cannot be taken into account by the fluid number Fr, the actual condition of the hull is determined. It is not possible to calculate a control parameter that perfectly matches the situation. Accordingly, the feedforward command steering angle signal U _FF determined by the feedforward control does not necessarily command the optimum steering angle U, and therefore, the difference between the bow direction φ and the reference course r (deflection angle φ _err ) May occur.

Therefore, the feedforward steering angle correcting unit 23, the so deflection angle phi _err becomes zero, so as to determine a feedforward command steering angle correction value U _{FF_d} for correcting the feedforward command steering angle signal U _FF It is configured. Further, the Froude number Fr is input to the feedforward steering angle correction unit 23. The feedforward steering angle correction unit 23 determines a feedforward command steering angle correction value U _{FF_d} based on the fluid number Fr and the deviation angle φ _err . Thus, by determining the feedforward command steering angle correction value U _{FF_d} based on Froude number Fr, it can be corrected feedforward command steering angle signal U _FF according to the actual situation of the hull.

Feedforward command steering angle signal U _FF and feedforward command steering angle correction value U _{FF_d} is added, the corrected feedforward command steering angle signal U _{FF_c} generated. The corrected feedforward command steering angle signal U _{FF_c} is output from the steering angle control unit 7 as the command steering angle signal U _c .

  Next, control in the needle holding mode will be described. In the needle holding mode, the rudder angle control unit 7 mainly performs feedback control (specifically, PID control). That is, in the needle-holding mode, it is necessary to cancel the disturbance such as waves and winds and to move the hull 3 straight, so it is preferable to perform PID control with excellent stability.

  More specifically, the PID control unit (feedback control unit) 24, the PID control parameter determination unit 25, and the PID control parameter correction unit 26 function in the needle holding mode. On the other hand, in this maintenance mode, the feedforward control unit 21, the feedforward control parameter determination unit 22, and the feedforward steering angle correction unit 23 do not function.

The needle keeping mode is a mode in which the hull moves straight, and the reference course r is a constant value. Therefore, the declination φ _err in this mode is solely due to disturbances such as wind and waves. The purpose of the PID control unit 24 is to move the hull 3 straight by controlling the deviation angle φ _{err to} be zero.

The declination angle φ _err is input to the PID control unit 24. In addition, control parameters (proportional gain K _P , integration time K _I , derivative time K _D ) are input from the PID control control parameter determination unit 25 to the PID control unit 24. Using this control parameter, the PID control unit 24 outputs a PID command steering angle signal U _PID so that the deflection angle φ _err approaches zero. Since PID control is publicly known, detailed processing contents are omitted.

Next, the control parameter determination unit 25 for PID control will be described. That is, even when each control parameter for PID control is set to a fixed value, the control can be performed so that the deflection angle φ _err approaches zero. However, if the control parameter can be changed according to the dynamic change of the motion characteristic of the hull 3, more optimal control can be realized. Therefore, the PID control control parameter determination unit 25 is configured to determine control parameters (proportional gain K _P , integration time K _I , differentiation time K _D ) based on the fluid number Fr. As described above, when the fluid number Fr is used to determine the control parameter for PID control, the same effect as when the fluid number Fr is used to determine the filter constant in the filter constant determination unit 12 can be obtained. Can do.

As a method of determining the control parameters (proportional gain K _P , integration time K _I , derivative time K _D ) based on the Froude number Fr, an experiment is performed in advance in the same manner as the filter constant determination unit 12, and the optimum parameter is determined. A table indicating the relationship between the control parameter and the fluid number Fr may be stored.

For example, even if the declination angle φ _err is the same, the rudder angle U has to be increased for a ship in which the rudder is less effective. Therefore, the table is prepared so that the proportional gain K _P increases as the Froude number Fr decreases (as the rudder is less effective). Further, if the rudder is difficult to work, the hull 3 does not react even if the rudder angle U is changed finely and frequently, resulting in useless rudder. Therefore, in a situation where the rudder is difficult to work, it is necessary to set the control parameter so that the rudder angle U does not fluctuate finely. Therefore, as the Froude number Fr is smaller (as the rudder hard effectiveness), integration time K _I is large, so that the derivative time _the K _D decreases, you create the table.

The declination φ _err includes periodic fluctuations of high frequency due to disturbances such as waves and winds. Even if the steering angle U is changed so as to respond to the periodic fluctuations, the rudder angle φ _err turn into. Therefore, in the present embodiment, a PID control parameter correction unit 26 that corrects PID control parameters is provided so as not to respond to the periodic fluctuations.

The PID control parameter correction unit 26 receives the turning angular velocity φ ′ of the hull 3. The PID control parameter correction unit 26 detects a periodic variation of the deflection angle φ _err based on the disturbance based on the turning angular velocity φ ′, and corrects the control parameter so as not to respond to the periodic variation. The values (proportional gain correction value K _{P — d} , integration time correction value K I — _d , derivative time correction value K _{D — d} ) are determined. The PID control parameter correction unit 26 is configured to determine the correction value based on the fluid number Fr. Thereby, the correction value according to the actual situation of the hull 3 can be determined.

The control parameters (proportional gain K _P , integration time K _I , derivative time K _D ) determined by the PID control parameter determination unit 25 are the correction values (proportional gain correction value K) output by the PID control parameter correction unit 26. _{P_d} , integration time correction value K _{I_d} , and differentiation time correction value K _{D_d} ) are added to each other and output to the PID control unit 24. The PID control unit 24 performs PID control using the corrected control parameter, and outputs a PID command steering angle signal _UPID . This PID command steering angle signal _UPID is output from the steering angle control unit 7 as the command steering angle signal _Uc as it is.

As described above, the automatic steering method of the present embodiment is an automatic steering method that outputs the command steering angle signal U _c for the steering machine 2 so that the heading φ matches the set course φ _c , which is described below. The process is included. That is, this automatic steering method includes a fluid number calculation step and a rudder angle control step. In the fluid number calculation step, the fluid number Fr is calculated from the ship speed V and the hull length L. In the steering angle control step, a control parameter is determined based on the fluid number Fr, and a command steering angle signal U _c is determined based on the control parameter.

The automatic steering program according to the present embodiment is an automatic steering program that outputs a command steering angle signal U _c for the steering machine 2 so that the heading φ matches the set course φ _c, and includes the following steps. Yes. That is, this automatic steering program includes a fluid number calculation step and a steering angle control step. In the fluid number calculation step, the fluid number Fr is calculated from the ship speed V and the hull length L. In the steering angle control step, the control parameter is determined based on the fluid number Fr, and the command steering angle signal U _c is determined based on the control parameter.

The automatic steering device 1 according to the present embodiment is an automatic steering device that outputs a command steering angle signal U _c for the steering machine 2 so that the heading φ matches the set course φ _c, and is configured as follows. Has been. That is, the automatic steering device 1 includes a fluid number calculation unit 6 and a steering angle control unit 7. The fluid number calculation unit 6 calculates the fluid number Fr from the ship speed V and the hull length L. The steering angle control unit 7 determines a control parameter based on the fluid number Fr, and determines a command steering angle signal U _c based on the control parameter.

Thus, by determining a control parameter based on the fluid number Fr, a control parameter suitable for the situation of the hull 3 can be obtained. Further, since the fluid number Fr can be immediately calculated from the ship speed V and the hull length L, it is possible to immediately obtain a control parameter corresponding to a change in the situation. Further, since the Froude number Fr is a number obtained by making the ship speed V dimensionless using the hull length L, ships having the same Froude number Fr have similar motion characteristics even if the hull size is different. Then you can think. Therefore, by determining the control parameter using the Froude number Fr, it is possible to output an appropriate command steering angle signal U _c for any size hull.

  In the automatic steering device 1 of the present embodiment, the steering angle control unit 7 includes a feedforward control unit 21 that performs feedforward control in the needle changing mode, and a PID control unit 24 that performs feedback control in the needle holding mode. ing.

  That is, by performing feedforward control at the time of changing the needle, it is possible to improve the responsiveness of changing the steering angle at the time of changing the needle. Further, by performing feedback control at the time of keeping the needle, the course can be stabilized and the straightness of the hull 3 can be improved.

Further, the automatic steering device 1 of the present embodiment is configured as follows. That is, the steering angle control unit 7 includes a feedforward control unit 21, a reference course determination unit 5, and a feedforward control parameter determination unit 22. The feedforward control unit 21 performs feedforward control in the needle changing mode. The reference course determining unit 5 determines the reference course r based on the set course φ _c after the change of needle and the fluid number Fr. The feedforward control parameter determination unit 22 determines the turning index K and the tracking index T based on the fluid number Fr. The feedforward control unit 21 performs the feedforward control based on the reference course r, the turning index K, and the followability index T.

  Thus, by determining each parameter (reference course r, turning index K and followability index T) based on the Froude number Fr, it is possible to perform a turning operation appropriately according to the state of the hull.

  Further, the automatic steering device 1 of the present embodiment is configured as follows. That is, the steering angle control unit 7 includes a PID control unit 24, a PID control parameter determination unit 25, and a PID control parameter correction unit 26. The PID control unit 24 performs PID control in the needle holding mode. The PID control parameter determination unit 25 determines a PID control parameter based on the fluid number Fr. The PID control parameter correction unit 26 determines a correction parameter for PID control based on the turning angular velocity of the hull 3 and the fluid number Fr. Then, the PID control unit 24 performs the PID control using the PID control parameter corrected by the correction parameter.

  That is, since PID control is particularly effective as control for matching a control value that varies due to disturbance to a target value, it is preferable to use it for control during needle holding as described above. Further, by determining the PID control parameter based on the fluid number Fr, PID control suitable for the situation of the ship can be performed. Further, by calculating a correction parameter for PID control based on the turning angular velocity, it is possible to appropriately suppress disturbance due to, for example, waves or winds.

  In the above embodiment, the filter constant determination unit 12, the feedforward control parameter determination unit 22, the feedforward steering angle correction unit 23, and the PID control parameter determination unit 25 include a cruise speed in addition to the fluid number Fr. And information that specifies the boat type. Each said structure is comprised so that the said various parameters may be determined also considering the information which designates cruise speed and whether it is a boat type. This point will be described below.

  The cruise speed is a ship speed at which the hull 3 can be operated most efficiently, and is usually about 80% of the maximum ship speed. This cruise speed is set in advance by the user. The user also sets in advance whether or not the hull 3 is a boat type.

  A boat-type vessel is in a sliding state when the fluid number exceeds about 0.4, and exhibits different movement characteristics from a non-sliding vessel. Therefore, in the present embodiment, for a ship of a boat type and having a fluid number at a cruise speed exceeding 0.4 (hereinafter referred to as a sliding ship), the other ship (hereinafter referred to as a drainage type). The control parameter determination method is different from that of the ship. For example, in the filter constant determination unit 12 and the PID control control parameter determination unit 25, tables for determining each parameter are set separately for the sliding ship and the drainage ship. Then, based on the cruise speed and boat type set by the user, it may be determined whether the hull 3 is a sliding type or a drainage type, and the table is switched according to the determination result.

As an example, FIG. 5 schematically shows a table showing the relationship between the differential time K _D for PID control and the Froude number Fr in the form of a graph. As shown in FIG. 5, if the waste water type of the ship, can be regarded as substantially proportional to the derivative time K _D and fluid number Fr. On the other hand, in the case of a planing type ship, since the hull starts to slide when the Froude number Fr is around 0.4, the motion characteristics greatly change around Fr = 0.4. Therefore, when the table is created for a planing ship, it is preferable that the table has a graph whose slope changes near Fr = 0.4, as shown in FIG. In this way, two types of tables are prepared for the drainage type ship and the sliding type ship, and the table is switched according to the cruise speed and the boat type set by the user. Steering angle control can be realized.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  In the above embodiment, the automatic steering device 1 is configured by software and hardware. However, part or all of the functions of the automatic steering device 1 may be realized by dedicated hardware.

  In the above embodiment, the reference course r is obtained by a low-pass filter. However, as in Patent Document 1, the reference course r may be obtained in consideration of the operable range of the steering angle of the steering machine 2.

  In the above feedforward control, the Nomoto primary approximation model is used, but the present invention is not limited to this, and an appropriate model can be used.

  In the above-described embodiment, the parameter determination method is different between the sliding type and the drainage type. However, the configuration that distinguishes between the sliding type and the drainage type can be omitted.

In the above embodiment, the filter constant, the control parameter for PID control, and the like are determined using a table prepared in advance, but the present invention is not limited to this. That is, since the feature of the present invention is to determine various parameters based on the fluid number Fr, the parameter determination method is not particularly limited. For example, as in the example schematically shown in FIG. 5, when a simple proportional relationship or the like can be assumed between the control parameter (the differential time K _{D in} the example of FIG. 5) and the fluid number Fr, the table is Without preparing, it can be configured to calculate various parameters based on a mathematical formula with the Froude number Fr as an argument (in the above embodiment, the turning index K and the tracking index T are determined by this type of method). Determined).

DESCRIPTION OF SYMBOLS 1 Automatic steering device 2 Steering machine 3 Hull 5 Reference course determination part 6 Fluid number calculation part 7 Steering angle control part 21 Feedforward control part 24 PID control part (feedback control part)
φ Heading φ _c Setting course r Reference course U Steering angle U _c Command steering angle signal (command steering angle)
Fr fluid number

Claims (6)

An automatic steering device that outputs a command steering angle with respect to a steering machine so that a heading coincides with a set course,
A fluid number calculation unit for calculating the fluid number from the ship speed and the hull length;
A control parameter is determined based on the fluid number, and a steering angle control unit that determines the command steering angle based on the control parameter;
An automatic steering apparatus comprising: The automatic steering device according to claim 1,
The rudder angle control unit
A feed-forward control unit that performs feed-forward control at the time of needle change,
A feedback control unit that performs feedback control at the time of holding,
An automatic steering apparatus comprising: The automatic steering device according to claim 1 or 2,
The rudder angle control unit
A feed-forward control unit that performs feed-forward control at the time of needle change,
A reference course determining unit that determines a reference course based on the set course after the course change and the fluid number;
A feedforward control parameter determining unit that determines a turning index and a following index based on the fluid number;
With
The automatic steering apparatus, wherein the feedforward control unit performs the feedforward control based on the reference course, the turnability index, and the followability index. The automatic steering device according to any one of claims 1 to 3,
The rudder angle control unit
A feedback control unit for performing PID control at the time of needle holding;
A PID control parameter determining unit that determines a PID control parameter based on the fluid number;
A control parameter correction unit for PID control that determines a correction parameter for PID control based on the turning angular velocity of the hull and the fluid number;
With
The automatic steering apparatus, wherein the feedback control unit performs the PID control using the control parameter for PID control corrected by the correction parameter. An automatic steering program that outputs a command rudder angle for a steering machine so that the heading coincides with a set course,
A fluid number calculating step for calculating a fluid number from a ship speed and a hull length;
Steering angle control step for determining a control parameter based on the fluid number, and determining the command steering angle based on the control parameter;
An automatic steering program that causes an automatic steering device to execute a process including: An automatic steering method for outputting a command rudder angle with respect to a steering machine so that a heading coincides with a set course,
A fluid number calculating step for calculating a fluid number from a ship speed and a hull length;
Rudder angle control step of determining a control parameter based on the fluid number, and determining the command rudder angle based on the control parameter;
Including an automatic steering method.

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