JP5036366B2 - Towing rope length control method and apparatus - Google Patents

Description

  The present invention relates to a method and an apparatus for controlling the length of a rope for towing a towed body such as a trawl net of a trawler or an underwater observation instrument of an ocean research ship using an actuator such as a winch.

  Conventionally, trawlers of trawlers, underwater observation vessels of marine research vessels, etc. (in this specification and claims, these towed objects are collectively referred to as “towed bodies”). Towed by a ship. Such a towed body is towed underwater with a rope drawn out from a ship (“rope” in this specification and claims includes all “ropes” such as a wire rope). Has been. Hereinafter, a trawl network towed by a trawler will be described as an example of such a towed body.

  FIG. 4 is a schematic plan view showing an example of a trawl network towed by a trawler. As shown in the figure, the trawl 51 is towed by ropes 54L and 54R fed out from winches 53L and 53R provided on a trawler 52 (ship). The lengths of the ropes 54L and 54R are controlled in a state where a predetermined tension is maintained by the winches 53L and 53R. The winches 53L and 53R are generally driven by hydraulically driven actuators 55L and 55R. The tension and length of the ropes 54L and 54R are controlled by rotating the winches 53L and 53R forward / reversely so that the tension of the ropes 54L and 54R generated by towing the trawl net 51 falls within a certain range. The ropes 54L and 54R are unwound or wound by the winches 53L and 53R.

  In the case of the trawl net 51, it is usually towed by the trawl ship 52 through the spreaders 56L and 56R (hereinafter referred to as “otter board”) for opening the front face thereof. The otter boards 56L and 56R have a shape that generates a force that opens a front surface of the trawl net 51 by receiving a water flow. By traversing the otter boards 56L and 56R with the ropes 54L and 54R drawn from the trawler 52, the trawl net 51 is towed while the front surface is kept open.

As a conventional technique of this type, a hydraulic pump that supplies hydraulic oil to a hydraulic motor that drives a winch that feeds out a rope is provided, and the electric motor is driven based on fluctuations in load current of the electric motor that rotationally drives the hydraulic pump. There is one in which the tension of the rope is held at a set value by controlling the torque (see, for example, Patent Document 1).
JP 2006-199398 A

  By the way, whenever the trawler 52 sails, the hull is always shaken (the “sway” in the specification and claims includes all the shakes acting on the hull, such as rolling, yawing, and pitching). . FIG. 5 is a diagram showing an example of the oscillation frequency acting on the hull, and the ship generates oscillation at a certain frequency (period) as shown by a solid line or a dotted line due to the influence of disturbance such as waves or the shape of the hull. .

  Since the ropes 54L and 54R are pulled on the plus side of the hull of the hull and the ropes 54L and 54R are loosened on the minus side, the winch 53L and the rope 54L and 54R are within a certain range as described above. There is a case where 53R frequently performs the feeding / rewinding operation of the ropes 54L and 54R. However, the rope length control operation that compensates for the frequent feeding / rolling operation of the ropes 54L and 54R is originally unnecessary control, and prevents stable control of the trawl net 52.

  In addition, since the vibration frequency of the hull changes depending on disturbance characteristics such as waves, navigation speed, drafts, etc., even if the length of the ropes 54L and 54R is controlled to a certain length according to the trawl net 52, the hull vibration is controlled. The rope length control operation for compensating for the feeding / rolling operation of the ropes 54L and 54R due to the change of the frequency may be frequently repeated, and the control according to the trawl net 52 is also difficult. The frequent control of the rope length by the frequent feeding / rolling operation of the towed ropes 54L and 54R is the same even for a towing body other than the trawl. Inhibit.

  In Patent Document 1, the rope tension can be maintained, but the rope length cannot be stably controlled.

  Accordingly, an object of the present invention is to provide a tow rope length control method and apparatus capable of stably controlling a rope length by suppressing a rope length control operation that compensates for a rope unwinding / rolling operation caused by a hull motion. And

In order to achieve the above object, the tow rope length control method of the present invention provides a rope length deviation between the rope length target value based on a rope length target value for towing a towed body and an actual rope length feedback signal. And output the amount of rope operation based on the rope length deviation, and continuously identify the oscillation frequency of the hull towing the towed body from the time series data of the rope length , and the band of the identified oscillation frequency Is continuously reduced from the amount of rope operation so as to suppress the control operation to compensate for the rope unwinding / rolling operation in the vibration frequency band of the hull . The above-mentioned “identification of the vibration frequency of the hull” refers to determining a frequency regarded as a vibration from an external force acting on the hull. As a result, stable rope length can be controlled without cutting the fluctuation component of the rope unwinding / rolling action caused by the hull movement by the filter circuit and controlling the unnecessary fluctuation of the rope length due to the hull movement. You can

Furthermore, since the continuously identify upset frequency of the ship body, be upset frequency of the hull is changed, it is possible to perform stable control by suppressing the control of the frequency band corresponding to the upset.

On the other hand, the tow rope length control device of the present invention includes a rope length control device for controlling a rope operation amount, a rope length target value for towing a towed body, and a feedback signal of an actual rope length, and A hull for towing the towed body and having a function of outputting a rope operation amount to the rope length control device based on the rope length deviation of the deviation detecting unit. A vibration frequency identification machine for identifying the vibration frequency of the ship is provided, the vibration frequency identification machine continuously identifies the vibration frequency of the hull from the time series data of the rope length, and the band of the identified vibration frequency is determined from the amount of rope operation. A filter circuit is provided that suppresses the control operation that continuously reduces and compensates for the rope unwinding / rolling operation in the vibration frequency band of the hull . As the oscillation frequency detector, an FFT analyzer, a sequential least square method, or the like is used. Further, the filter circuit for reducing the hull vibration frequency is provided so as to cut the hull vibration frequency at any one of the rope length feedback signal, the rope length deviation, and the rope operation amount. According to this device, stable rope length control can be performed by cutting the fluctuation component of the rope feeding / revolution caused by the hull movement by the filter circuit so that unnecessary fluctuation of the rope length due to the hull movement is not controlled. It is possible to provide a length control device that can be used.

Furthermore, since the continuously identify upset frequency of the hull in motion rocking frequency identification device, it is possible to perform stable control by suppressing the control of the frequency band corresponding to upset that changes every moment.

  According to the present invention, it is possible to suppress the rope length fluctuation control for towing the towed body caused by the hull movement by the means described above, and thus it is possible to control the towed rope length control of the towed body stably. It becomes.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a basic configuration of a length control device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a configuration related to a fluctuation frequency identification machine in the length control device shown in FIG. FIG. 3 is a drawing showing an example of a notch filter in the control device shown in FIG. 1, wherein (a) is a Bode diagram showing the relationship between gain and frequency, and (b) is a Bode wire showing the relationship between phase difference and frequency. FIG. Also in this embodiment, a trawl network towed by a trawler will be described as an example of a towed body. In the following description, the same components as those shown in FIG.

  As shown in the block diagram of FIG. 1, according to the length control device 1, a signal corresponding to the rope length target value 2 is sent from the rope length controller 3 as a rope operation amount 4 to the control system (rope of the winches 53L and 53R). The lengths of the ropes 54L and 54R are controlled by the winches 53L and 53R so as to match the rope length target value 2. Further, the actual rope length is compared with the rope length target value 2 by the comparison unit 6 (deviation detection unit) as the rope length feedback 5, and the rope length deviation 7 is input to the rope length controller 3, and this rope length control is performed. The rope operation amount 4 output from the machine 3 to the control system of the winches 53L and 53R is feedback-controlled by the actual rope length.

  As shown in FIG. 2, the length control device 1 is provided with a vibration frequency identification device 8, and the vibration frequency identification device 8 identifies the vibration frequency 9 of the hull. As this oscillating frequency identifier 8, an FFT analyzer, a sequential least square method, or the like is used, and the oscillating frequency is identified by frequency analysis based on the signal of the rope length feedback 5. In addition, the vibration frequency identification device 8 may be one that can identify the vibration frequency by analyzing the frequency based on the pitch angle, the pitch rate, or the like of the hull. According to the shaking frequency identification device 8, the shaking frequency can be identified even if the shaking frequency of the hull changes. As for the shaking of the hull, the frequency of shaking caused by a wave having a constant period as shown by the solid line or dotted line in FIG. 5 is regarded as shaking.

  Then, by using the oscillation frequency 9 identified by the oscillation frequency identifier 8 in the notch filter 10 which is a filter circuit, only the component of the oscillation frequency is reduced (cut). As shown in FIG. 1, the notch filter 10 is applied at any one of the position (x) of the rope length feedback, the position (y) of the rope length deviation, and the position (z) of the rope operation amount. What is necessary is just to insert in series, and it should just be a position which can reduce the component of ship hull oscillation frequency 9 from the signal of rope length target value 2. Thereby, the length control of the ropes 54L and 54R is not frequently performed in the band of the vibration frequency of the hull.

  As shown in FIG. 3A, the notch filter 10 has a sensitivity (gain) reduced by a frequency band that is regarded as shaking. As shown in FIG. 3B, since the phase becomes zero in a band other than the frequency at which the notch is applied, the rope length control can be performed stably. In these diagrams, the case where the parameter “ζ” for determining the depth of the notch is changed is shown.

  Further, the hull vibration frequency 9 to be identified by the vibration frequency identification machine 8 is identified on-line from the rope length time-series data, and the fluctuation frequency 9 is a notch frequency that is reduced by the notch filter 10. Even if the oscillation frequency changes, the oscillation frequency is specified, and the notch filter 10 appropriately reduces the signal component in the oscillation frequency band, thereby suppressing useless responses of the winches 53L and 53R due to the hull oscillation. be able to.

  According to the tow rope length control device 1 configured as described above, in the length control of the ropes 54L and 54R towing the trawl net 51, the band of the hull vibration frequency 9 identified by the vibration frequency identifier 8 is used. Is significantly reduced from the target value of the rope length by the notch filter 10, so that it is possible to suppress a wasteful control operation for compensating for the operation of feeding / retracting the ropes 54 </ b> L and 54 </ b> R repeated due to the shaking of the hull. In addition, since normal control is performed in a portion other than the band of the oscillation frequency 9, stable length control of the ropes 54L and 54R towing the trawl net 51 can be performed.

  In other words, without affecting the signal for controlling the length of the normal ropes 54L and 54R, the hull frequency component is reduced to compensate for the feeding / retracting operation of the ropes 54L and 54R in the frequency band of the hull. The control operation to be performed can be suppressed, and the control operation to compensate the feeding / rolling operation of the ropes 54L and 54R by appropriately applying the notch filter 10 even when the hull oscillation frequency changes is suppressed. be able to.

  Moreover, although the hull vibration frequency changes depending on the ship condition and disturbance, the hull vibration frequency is identified online while controlling the rope length deviation by feedback control of the actual rope length with respect to the rope length target value 2. Since the control is performed so that the gain of the shaking frequency is lowered, the rope length control in which the component of the shaking frequency of the hull is always reduced and stable control can be performed. That is, even if the ship's vibration frequency changes every moment in the sea state where swells or the like are generated, the rope 54L, in the vibration frequency band is applied by appropriately applying the notch filter 10 to the band of the changed vibration frequency. It is possible to suppress a control operation that attempts to compensate for the 54R feed / roll-in operation.

  In addition, the rope generated by trying to compensate for the frequent unwinding / winding operation of the ropes 54L and 54R by suppressing the control operation to compensate for the frequent unwinding / winding operation of the rope. It is also possible to prevent deterioration due to tension fluctuations of 54L and 54R.

  Moreover, according to the length control apparatus 1 of this embodiment, it is also realizable by adding the notch filter 10 and the oscillation frequency identification machine 8 (oscillation frequency identification algorithm) with respect to the existing rope control apparatus. This is possible, and a significant increase in equipment costs can be suppressed.

  On the other hand, in the above embodiment, the hull sway frequency is obtained by the FFT analyzer of the sway frequency identification machine 8 or the sequential least square method based on the signal of the rope length feedback 5, but the hull is provided with an inclinometer or the like. If these devices can be used to directly measure the hull motion to measure the shaking frequency, it is also possible to capture the signal as a shaking frequency and use it. For example, when working in a state where a fixed point is held, if it is known that the oscillation frequency falls within a predetermined range, a frequency band range for the oscillation frequency 9 is set in advance, and the gain of the frequency band is set. May be reduced by the notch filter 10.

  Further, a detector for detecting the hull oscillation frequency in a state where the fixed point is held is provided so that the frequency of the notch filter 10 can be changed in accordance with the variable parameter output according to the oscillation frequency 9 detected by the detector. According to this configuration, even if the vibration frequency of the hull changes, the signal component is reduced by applying the notch filter 10 to the frequency band corresponding to the vibration frequency 9, so that it is possible to suppress useless responses of the winches 53L and 53R. .

  In the above-described embodiment, the trawl network is described as an example of the towed body. However, the towed body such as an observation apparatus can be similarly controlled, and the towed body is not limited to the trawl network. In this case, even if the winches 53L and 53R are other actuators, the same control can be performed.

  Further, the above-described embodiment shows an example, and various modifications can be made without departing from the gist of the present invention, and the present invention is not limited to the above-described embodiment.

  The tow rope length control method according to the present invention is useful for towing a towed body that wants to control a stable rope length by suppressing a compensation operation of a component in which the rope unwinding / rolling operation caused by the hull motion is repeated. is there.

It is a block diagram which shows the basic composition of the length control apparatus which concerns on one embodiment of this invention. It is a block diagram which shows the structure regarding the oscillation frequency identification machine in the length control apparatus shown in FIG. 2A and 2B are diagrams illustrating an example of a notch filter in the control device illustrated in FIG. 1. FIG. 2A is a Bode diagram illustrating a relationship between gain and frequency, and FIG. 2B is a Bode diagram illustrating a relationship between phase difference and frequency. It is a schematic plan view which shows an example of the trawl net towed by the trawler. It is a diagram which shows an example of the oscillation frequency which acts on a hull.

Explanation of symbols

1 ... Length control device
2 ... Rope length target value
3 ... Rope length controller
4 ... Rope operation amount
5 ... Rope length feedback
6 ... Comparison part
7 ... Rope length deviation
8 ... Oscillation frequency identification machine
9 ... Fluctuation frequency
10 ... Notch filter
51 ... trawl net 53L, 53R ... winch 54L, 54R ... rope

Claims (2)

Obtaining the rope length deviation of the rope length target value based on the rope length target value towing the towing body and the actual rope length feedback signal, and outputting the rope operation amount based on the rope length deviation,
The swing frequency of the hull towing the towed body is continuously identified from the time-series data of the rope length , and the band of the identified swing frequency is continuously reduced from the amount of rope operation so that the A tow rope length control method that suppresses a control operation to compensate for the unwinding / rolling operation of the tow rope. A rope length control device that controls the amount of rope operation, and a deviation detector that obtains a rope length deviation from the rope length target value based on a rope length target value for towing the towed body and an actual rope length feedback signal. ,
With the function of outputting the rope operation amount to the rope length control device based on the rope length deviation of the deviation detector,
A shaking frequency identification machine for identifying the shaking frequency of the hull towing the towed body is provided, and the shaking frequency identification machine continuously identifies the shaking frequency of the hull from the time series data of the rope length, and The length of the towing rope characterized by providing a filter circuit for continuously reducing the band from the amount of rope operation and suppressing the control operation to compensate for the rope unwinding / rolling operation in the hull frequency band Control device.

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