Abstract:
An underwater propelling apparatus, includes a body and a plurality of vibrating units. The plurality of vibrating units are placed in parallel to each other on a rear side of the body. Each of the plurality of vibrating units vibrates repeatedly and reciprocally to produce a thrust.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an underwater propelling apparatus. More particularly, the present invention relates to an underwater propelling apparatus used for a fishing boat, a working boat, a submarine searching boat and a submarine working boat and the like.  
           [0003]    2. Description of the Related Art  
           [0004]    As a conventional underwater propelling apparatus, a screw propeller  51  is used for a submarine searching boat  52 , as shown in FIG. 1.  
           [0005]    The screw propeller  51  generates a thrust only in its rotation axis direction. Thus, the directional control of the submarine searching boat  52  requires an auxiliary apparatus such as a rudder  53 , a side thruster  54  and the like. Hence, the performances of the directional control and a position keeping control are limited as compared with a straightly propelling performance.  
           [0006]    Also, there may be a fear that the screw propeller  51  or the side thruster  54  catches nearby matter. Thus, the limit on usage is imposed from the viewpoint of safety.  
           [0007]    In a case of a conventional screw propelling apparatus of the submarine searching boat, mud on sea bottom is confused, and noise is made to thereby disturb the searching operation. Also, its small energy disables a long time operation. Thus, this has the above-mentioned problems.  
           [0008]    An underwater propelling apparatus is desirable for stably carrying out a propelling operation and a steering operation.  
           [0009]    An underwater propelling apparatus is desirable for stably carrying out a directional control and a position keeping control.  
           [0010]    An underwater propelling apparatus is desirable for effectively obtaining a thrust.  
           [0011]    An underwater propelling apparatus is desirable for freely carrying out not only a propelling operation but also a steering operation.  
           [0012]    An underwater propelling apparatus is desirable for freely carrying out a directional control and a position keeping control.  
           [0013]    An underwater propelling apparatus is desirable which has an excellent silence property.  
           [0014]    By the way, Japanese Laid Open Patent Application (JP-A-Heisei, 11-152085) in relation to the application of this applicant discloses the following underwater running body. That is, in the underwater running body, a plurality of wings, which are vibrated by the reciprocating rotations of rotation shafts fixed to the front edge, are installed in series. Then, the joint control of the respective rotation shafts enables the plurality of wings to be flexibly actuated such as a tail fin of a fish as a whole. Thus, the thrust can be obtained. In addition, the steering operation can be done by controlling a vibration center of each of the wings. Also, the floating/sinking control is carried out by a water filling/draining operation for a tank.  
         SUMMARY OF THE INVENTION  
         [0015]    The present invention is accomplished in view of the above mentioned problems. Therefore, an object of the present invention is to provide an underwater propelling apparatus for stably carrying out a propelling operation and a steering operation.  
           [0016]    Another object of the present invention is to provide an underwater propelling apparatus for stably carrying out a directional control and a position keeping control.  
           [0017]    A still another object of the present invention is to provide an underwater propelling apparatus for effectively obtaining a thrust.  
           [0018]    A still another object of the present invention is to provide an underwater propelling apparatus for freely carrying out not only a propelling operation but also a steering operation.  
           [0019]    A still another object of the present invention is to provide an underwater propelling apparatus for freely carrying out a directional control and a position keeping control.  
           [0020]    A still another object of the present invention is to provide an underwater propelling apparatus having an excellent silence property.  
           [0021]    In order to achieve an aspect of the present invention, an underwater propelling apparatus, includes: a body; and a plurality of vibrating units, which are placed in parallel to each other on a rear side of the body, and wherein each of the plurality of vibrating units vibrates repeatedly and reciprocally to produce a thrust. The underwater propelling apparatus of the present invention uses a technique for controlling an elastically vibrating wing. The underwater propelling apparatus of the present invention is the submarine boat (a non-towed underwater vehicle) itself.  
           [0022]    In this case, the underwater propelling apparatus is an submarine boat which is a non-towed underwater vehicle.  
           [0023]    Also in this case, the each of the plurality of vibrating units includes a plurality of vibrators which are placed in series and can be controlled independently of each other.  
           [0024]    Further in this case, the each of the plurality of vibrating units includes a plurality of vibrators which are placed in series and can be controlled independently of each other.  
           [0025]    In this case, the each of the plurality of vibrators placed in series is elastic, and one vibrator positioned on the rear side from the body of the plurality of vibrators placed in series has a higher elastic modulus than that of another vibrator.  
           [0026]    Also in this case, the each of the plurality of vibrators placed in series is elastic, and one vibrator positioned on the rear side from the body of the plurality of vibrators placed in series has a higher elastic modulus than that of another vibrator.  
           [0027]    Further in this case, the each of the plurality of vibrators placed in series is elastic, and one vibrator positioned on the rear side from the body of the plurality of vibrators placed in series has a higher elastic modulus than that of another vibrator.  
           [0028]    In this case, the underwater propelling apparatus is used in a propelled body propelled by the underwater propelling apparatus, and wherein the plurality of vibrating units are placed at locations to be separated from each other on a virtual line substantially orthogonal to a direction in which the propelled body is propelled.  
           [0029]    Also in this case, the underwater propelling apparatus is used in a propelled body propelled by the underwater propelling apparatus, and wherein the plurality of vibrating units are placed at locations to be separated from each other on a virtual line substantially orthogonal to a direction in which the propelled body is propelled.  
           [0030]    Further in this case, the underwater propelling apparatus is used in a propelled body propelled by the underwater propelling apparatus, and wherein the plurality of vibrating units are placed at locations to be separated from each other on a virtual line substantially orthogonal to a direction in which the propelled body is propelled.  
           [0031]    In this case, the plurality of vibrating units are placed at locations to be separated from each other on a virtual line substantially orthogonal to a direction in which the underwater propelling apparatus is propelling.  
           [0032]    Also in this case, the underwater propelling apparatus further includes: a tank into and from which water can be filled and drained to control floating/sinking state of the body; and a water filling/draining control unit which controls operations filling and draining the water into and from the tank.  
           [0033]    Further in this case, the body includes a plurality of underwater running units and a bed unit through which the plurality of underwater running units are linked to each other, and wherein the plurality of vibrating units are provided in a plurality of rear portions of the plurality of underwater running units, respectively, and wherein each of the plurality of underwater running units and the bed unit has an outer appearance formed by a smooth curve to reduce a resistance in an underwater.  
           [0034]    In this case, each of the plurality of underwater running units is substantially ellipsoidal in shape in which a longitudinal side of each of the plurality of underwater running units is longer when being viewed from a front of each of the plurality of underwater running units, and substantially ellipsoidal in shape in which a lateral side of each of the plurality of underwater running units is longer when being viewed from a side of each of the plurality of underwater running units and on a flat plane of each of the plurality of underwater running units.  
           [0035]    Also in this case, the bed unit is substantially ellipsoidal in shape in which a lateral side of the bed unit is longer when being viewed from a side of the bed unit, and the bed unit is substantially rectangular in shape in which a lateral side of the bed unit is longer when being viewed from a front of the bed unit and on a flat plane of the bed unit.  
           [0036]    Further in this case, the underwater propelling apparatus is an submarine boat, and wherein the plurality of underwater running units are designed such that separation distance between the plurality of underwater running units is longer than a width dimension of a rear portion of the submarine boat.  
           [0037]    In order to achieve another aspect of the present invention, an underwater propelling apparatus, includes: a body; a first vibrating unit placed on a rear side of the body in which a first vibrator vibrated by a reciprocating rotation of a first rotation shaft and a second vibrator vibrated by a reciprocating rotation of a second rotation shaft are arranged in series; a second vibrating unit that is placed on the rear side of the body and placed in parallel to the first vibrating unit in a horizontal direction, in which a third vibrator vibrated by a reciprocating rotation of a third rotation shaft and a fourth vibrator vibrated by a reciprocating rotation of a fourth rotation shaft are arranged in series; first to fourth actuators which rotates the first to fourth rotation shafts, respectively; a vibrator command generator which outputs a control signal to set respective amplitudes, frequencies and vibration centers of the first to fourth vibrators associated with the reciprocating rotations of the first to fourth rotation shafts and phases between the first to fourth vibrators to control the first to fourth rotation shafts jointly and respectively; and an angular servo driver which generates signals to control the first to fourth actuators, respectively, on the basis of the control signal.  
           [0038]    In this case, the each the first to fourth vibrators is elastic, and the second vibrator positioned on the rear side from the body of the first and second vibrators arranged in series has a higher elastic modulus than that of the first vibrator, and the fourth vibrator positioned on the rear side from the body of the third and fourth vibrators arranged in series has a higher elastic modulus than that of the third vibrator.  
           [0039]    Also in this case, the first to fourth rotation shafts are placed in a horizontal direction.  
           [0040]    Further in this case, the first to fourth rotation shafts are placed in a horizontal direction such that it is possible to change a submarine depth of the underwater propelling apparatus. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0041]    [0041]FIG. 1 is a side view showing a conventional underwater running body;  
         [0042]    [0042]FIG. 2A is a side view diagrammatically showing an embodiment of an underwater propelling apparatus of the present invention;  
         [0043]    [0043]FIG. 2B is a plan view showing the underwater propelling apparatus;  
         [0044]    [0044]FIG. 2C is a front view showing the underwater propelling apparatus;  
         [0045]    [0045]FIG. 3 is a plan view diagrammatically showing an inner configuration of the embodiment of the underwater propelling apparatus of the present invention;  
         [0046]    [0046]FIG. 4 is a side view diagrammatically showing the inner configuration of the embodiment of the underwater propelling apparatus of the present invention;  
         [0047]    [0047]FIG. 5 is a block diagram diagrammatically showing a system for controlling two sets of wings connected in series in the embodiment of the underwater propelling apparatus of the present invention;  
         [0048]    [0048]FIG. 6 is a block diagram diagrammatically showing a system for controlling a pair of right and left wings in the embodiment of the underwater propelling apparatus of the present invention;  
         [0049]    [0049]FIG. 7 is a side view diagrammatically showing a condition that the embodiment of the underwater propelling apparatus of the present invention is applied to a fishing boat; and  
         [0050]    [0050]FIG. 8 is a plan view diagrammatically showing a condition that the embodiment of the underwater propelling apparatus of the present invention is applied to a submarine boat. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0051]    An embodiment of an underwater propelling apparatus of the present invention will be described below with reference to the attached drawings.  
         [0052]    [0052]FIG. 2A is a side view showing the underwater propelling apparatus in this embodiment, FIG. 2B is a plan view showing the underwater propelling apparatus, and FIG. 2C is a front view showing the underwater propelling apparatus. FIG. 7 is a side view diagrammatically showing the condition that the underwater propelling apparatus in this embodiment is installed in a boat. FIG. 8 is a plan view diagrammatically showing the condition that the underwater propelling apparatus in this embodiment is installed in a submarine boat.  
         [0053]    By the way, although not shown, the underwater propelling apparatus in this embodiment is used in a condition that it is installed in another propelled body. In addition, it itself can function as an underwater vehicle (a submarine searching boat and the like) of a non-towed type.  
         [0054]    As shown in FIGS. 2A to  2 C, an underwater propelling apparatus  100  in this embodiment includes two underwater running units  2 ,  2  and a bed unit  41  through which the two underwater running units  2 ,  2  are linked to each other. The two underwater running units  2 ,  2  have the configurations equal to each other. Each of the underwater running unit  2  and the bed unit  41  has the outer appearance formed by a smooth curve in order to reduce the resistance in the underwater. The underwater running unit  2  is substantially ellipsoidal in shape in which a longitudinal side is longer when it is viewed from a front, and substantially ellipsoidal in shape in which a lateral side is longer when it is viewed from a side and on a flat plane. The bed unit  41  is substantially ellipsoidal in shape in which a lateral side is longer when it is viewed from a side, and it is substantially rectangular in shape in which a lateral side is longer when it is viewed from a front and on a flat plane.  
         [0055]    As shown in FIG. 7, the underwater propelling apparatus  100  is installed in a fishing boat  61 , and it propels the fishing boat  61 , and carries out the directional control or the position keeping control of the fishing boat  61 . Also, as shown in FIG. 8, the underwater propelling apparatus  100  is installed in a submarine boat  62 , and it propels the submarine boat  62 , and carries out the directional control or the position keeping control of the submarine boat  62 .  
         [0056]    In FIGS. 7, 8, each arrow X indicates one direction in which each of the fishing boat  61  and the submarine boat  62  are propelled. The two underwater running units  2 ,  2  are placed at the positions separated from each other on a virtual line (not shown) substantially orthogonal to the one direction X in which the fishing boat  61  or the submarine boat  62  is propelled, in the bed unit  41 .  
         [0057]    As shown in FIG. 8, the two underwater running units  2 ,  2  are designed such that the separation distance is longer than a width dimension (a dimension in the upper and lower direction of FIG. 8) of the rear of the submarine boat  62 . Although it is not shown in FIG. 7, the two underwater running units  2 ,  2  can be designed such that the separation length is longer than a width dimension (a dimension of a direction orthogonal to a paper surface) of the rear of the fishing boat  61 .  
         [0058]    As shown in FIGS. 7, 8, the underwater propelling apparatus  100  is installed in the fishing boat  61  or the submarine boat  62  at the bed unit  41 . As shown in FIG. 8, two lamps  42 ,  42  for illuminating the underwater are attached to the bed unit  41  of the underwater propelling apparatus  100  installed in the submarine boat  62 .  
         [0059]    The configuration of the underwater running unit  2  will be described below. As mentioned above, the configurations of the two underwater running units  2 ,  2  are equal to each other. So, only one underwater running unit  2  is described, and the explanation of the other underwater running unit  2  is omitted.  
         [0060]    As shown in FIGS. 2A, 2B,  3  and  4 , two sets of wings (also, referred to as vibration wings)  1   a,    1   b  are arranged in series in the tail of the underwater running unit  2 . The two sets of the wings  1   a,    1   b  arranged in series are jointly denoted as a wing (also, referred to as a vibration wing)  1 . Each of the two sets of the wings  1   a,    1   b  is made of a metallic plate in order to satisfy the strength and the thinness. The wing  1   b  positioned at the rear portion in the two sets of the wings  1   a,    1   b  has a higher elastic modulus than that of the wing  1   a.  Rotation shafts  4 ,  5  that can be rotatably reciprocated so as to vibrate (swing) the vibration wings  1   a,    1   b,  respectively, are fixed to a front edge of the vibration wings  1   a,    1   b.    
         [0061]    A vibration wing controller  6 , which has rotation shaft actuators  14 ,  15  (refer to FIG. 5) to perform a reciprocating rotation on the rotation shafts  4 ,  5 , respectively, is placed inside the underwater running unit  2 . A necessary electric power of the vibration wing controller  6  is supplied by a battery  16 .  
         [0062]    In this case, the battery  16  may be a charging type. In the case, it may be a non-contact charging type from the viewpoint of water proof finish, and an electromagnetic induction battery can be used.  
         [0063]    Moreover, the underwater propelling apparatus  100  includes an underwater wireless communication controller (not shown). Then, it is possible to communicate with the underwater propelling apparatus  100 , which is a direct underwater vehicle, from on the water, and possible to carry out a simple communication between the underwater devices.  
         [0064]    By the way, in FIGS. 3, 4, it is configured such that the batteries  16  are placed in the respective two underwater running units  2 ,  2 . However, instead of this configuration, a single battery  16  can be placed in a center of the bed unit  41 .  
         [0065]    As shown in FIG. 5, the vibration wing controller  6  includes an angular servo driver  13  and a vibration wing command generator  12 , in addition to the rotation shaft actuators  14 ,  15 . The angular servo driver  13  actuates the respective rotation shaft actuators  14 ,  15  so that the rotation shafts  4 ,  5  of the vibration wings  1   a,    1   b  are controlled respectively and jointly. The vibration wing command generator  12  sends a control signal  12   c  to the angular servo driver  13  so as to control the amplitudes, the frequencies, the phases and the vibration centers of the respective vibration wings  1   a,    1   b.    
         [0066]    As shown in FIG. 3, a front portion of the underwater running unit  2  is covered with a rigid or flexible front envelope  2   b.  The portion corresponding to the vibration wing  1   a  of the underwater running unit  2  is covered with a flexible envelope  2   c  such as a coating material made of soft fiber reinforced plastic (FRP). This envelope  2   c  is connected to the front envelope  2   b  at a set portion  2   a.  Similarly, the portion corresponding to the vibration wing  1   b  of the underwater running unit  2  is covered with a flexible envelope  2   d  such as the coating material made of the soft fiber reinforced plastic (FRP).  
         [0067]    Here, in each of the front envelope  2   b,  the envelope  2   c  and the envelope  2   d,  silicon resin and vinyl chloride can be simultaneously used from the viewpoint of the water proof property and the machining property, instead of the above-mentioned materials.  
         [0068]    In the underwater running unit  2 , the envelopes  2   c,    2   d  covering the vibration wings  1   a,    1   b  are made of the flexible material so that the tail of the unit  2  can be smoothly curved in association with the actions of the respective vibration wings  1   a,    1   b.  Here, the envelope  2   d  covering the vibration wing  1   b  is made of the material whose flexibility is higher than that of the envelope  2   c  covering the vibration wing  1   a.  This corresponds to the fact that the vibration wing  1   b  has the elastic modulus higher than that of the vibration wing  1   a.    
         [0069]    In the underwater running unit  2  in this embodiment, the vibration wing  1   b  on the tip side has the higher elastic modulus, and the envelope  2   d  has the higher flexibility. Thus, when the vibration wings  1   a,    1   b  are actuated, the vibration wing  1   b  on the tip side is flexed such as a lash, and it is further sharply vibrated. This enables the thrust to be effectively obtained.  
         [0070]    The underwater running unit  2  includes a tank  7  into and from which water can be filled and drained, in order to control the floating/sinking state of the underwater propelling apparatus  100 . As shown in FIG. 4, the underwater running unit  2  includes a piping system containing a pump  8  and switching valves  9 ,  10 , and a buoyancy controller  17  for controlling the pump  8  and the respective switching valves  9 ,  10  to control the buoyancy of the tank  7 , as the water filling/draining control mechanism of the tank  7 .  
         [0071]    By the way, in FIGS. 3, 4, the tanks  7 , the water filling/draining control mechanisms and the buoyancy controllers  17  are configured so as to be placed in the two underwater running units  2 ,  2 , respectively. However, instead of this configuration, the single tank  7 , the water filling/draining control mechanism and the buoyancy controller  17  can be configured in the center of the bed unit  41 .  
         [0072]    As shown in FIGS. 3, 6, a vibration wing controller  28  is placed inside the bed unit  41 . The vibration wing controller  28  is connected to the respective vibration wing controllers  6  of the two underwater running units  2 ,  2 . The vibration wing controller  28  controls the vibration wings  1 ,  1  of the right and left two underwater running units  2 ,  2 , in the right and left directions, respectively.  
         [0073]    The vibration wing controller  28  outputs an operation command  12 a and a sensor input  12 b to the respective vibration wing command generators  12  of the two vibration wing controllers  6  (refer to FIG. 5).  
         [0074]    The method of controlling the vibration wings  1 ,  1  of the right and left two underwater running units  2 ,  2  by using the vibration wing controller  28  will be described below.  
         [0075]    (1) A thrust implying a manipulated variable is represented by a thrust applied to the center of gravity in the underwater propelling apparatus  100 .  
         [0076]    (2) The thrust is distributed to the right and left vibration wings  1 ,  1  so that the thrust explained in the item (1) becomes the sum of the thrusts applied to the connection points to the body of the underwater propelling apparatus of the pair of right and left vibration wings  1 ,  1 .  
         [0077]    (3) When the steering operation is done, the difference between the respective thrusts of the right and left vibration wings  1 ,  1  is induced to thereby rotate the underwater propelling apparatus  100  in a desirable direction.  
         [0078]    The determination of the manipulated variable in the vibration wing command generator  12  for controlling the vibration wings  1   a,    1   b  in the respective underwater running units  2  and the control in the buoyancy controller  17  after the distribution of the thrust to the vibration wings  1 ,  1  in the right and left two underwater running units  2 ,  2  as mentioned above will be described below.  
         [0079]    (1) The thrust distributed to the underwater running unit  2  is decomposed into a horizontal component and a vertical component.  
         [0080]    (2) The magnitude of the thrust in the horizontal component is controlled on the basis of the amplitudes of the reciprocating rotations of the rotation shafts  4 ,  5  and the values of the frequencies. Also, the orientation (advance or retreat) in the forward and backward direction of the thrust is controlled on the basis of the phase between the rotation shafts  4 ,  5 . Then, the orientation of the thrust in the horizontal direction for the steering operation is controlled on the basis of the amount when the vibration center of the vibration wings  1   a,    1   b  is deviated from a central line  11  of this underwater running unit  2 .  
         [0081]    (3) The values of the amplitudes and the rotation speeds of the respective right and left vibration wings  1   a,    1   a,    1   b,    1   b  are determined on the basis of the thrusts in the horizontal directions to the respective right and left vibration wings  1 ,  1  which are distributed as mentioned above. Then, the respective vibration wing controllers  6  are controlled such that the angles around the respective rotation shafts  4 ,  4 ,  5 ,  5  cope with the above-mentioned amplitudes and the rotation speeds.  
         [0082]    (4) As for the magnitude of the thrust in the vertical component, the buoyancy adjustment is carried out such that the buoyancy controller  17  controls the amount of the water within the tank  7  through the pump  8  and the respective switching valves  9 ,  10 .  
         [0083]    The vibration wing command generator  12  receives the operation command (the thrust, the turning round angle, the buoyancy and the like)  12   a  and the sensor input (the speed and the like)  12   b,  and outputs the amplitudes and the frequencies of the respective rotation shafts  4 ,  5  whose standard wave forms are sine waves, and the vibration center and the phase between the rotation shafts  4 ,  5 , to define the motions of the vibration wings  1   a,    1   b.    
         [0084]    Here, the vibration center implies the angle between the central line  11  of the underwater running unit  2  and the central position between the swung angles of the vibration wings  1   a,    1   b.    
         [0085]    The angular servo driver  13  converts the outputs of the vibration wing command generators  12  into angular signals  13   a,    13   b  of the respective vibration wings  1   a,    1   b  to control the rotation shaft actuators  14 ,  15 .  
         [0086]    The control methods of the vibration wing controller  6 , the vibration wing controller  28  and the buoyancy controller  17  will be described below.  
         [0087]    (1) Study (Preparation) of Vibration Wing Command Generator  12   
         [0088]    The speed of the underwater running unit  2  (the relative speed if there is flow) and the optimal amplitude, the optimal frequency and the optimal phase difference of the vibration wing  1  for each thrust are determined by using the following procedure.  
         [0089]    (a) The underwater running unit  2  (or the underwater propelling apparatus  100 ) is fixed in a water bath, and a strain gauge is placed in order to measure the thrust.  
         [0090]    (b) The vibration wings  1   a,    1   b  are operated so as to give a constant flow to the water bath and generate the thrust. Here, the flow speed of the flow is treated as the speed of the underwater running unit  2 .  
         [0091]    (c) The combination of the amplitudes, the frequencies and the phase differences of the vibration wings  1   a,    1   b  when the total electric power consumption of the rotation shaft actuators  14 ,  15  becomes minimum under the condition that the particular thrust is generated, is determined by using an optimization method such as the steepest descent method.  
         [0092]    (d) The items (b), (c) are carried out under the combination of several kinds of the speeds and the thrusts, and the data are summed up in the format of the two-dimension table composed of the speed and the thrust.  
         [0093]    ( 2 ) Controlling Method of Vibration Wing Controller  6   
         [0094]    After the study of the vibration wing command generator  12  is ended in accordance with the above-mentioned procedure, the vibration wing controller  6  controls the vibration wings  1   a,    1   b  in accordance with the following procedure.  
         [0095]    (a) The vibration wing command generator  12  receives a thrust of the operation command (a wireless command from an external portion)  12   a  and a speed of the sensor input  12   b  (the reception from a speed meter attached to the underwater running unit  2 ), and interpolates the table studied in the item (1) to output the amplitudes, the frequencies and the phase differences of the vibration wings  1   a,    1   b  (refer to a symbol  12   c ).  
         [0096]    (b) The vibration wing command generator  12  receives the turning round angle of the operation command  12   a,  and multiplies a coefficient to output as the vibration center (refer to the symbol  12   c ). The coefficient is assumed to be the coefficient so that the maximum value of the vibration centers is normalized at the maximum value of the signals of the turning round angles.  
         [0097]    (c) When the amplitude (maximum angle) implying the output (refer to the symbol  12   c ) from the vibration wing command generator  12  is assumed to be A, the frequency (the number of the angular vibrations) implying that is assumed to be ω, the phase implying that is assumed to be α, the vibration center implying that is assumed to be K and the time is assumed to be t, the angular servo driver  13  outputs the angular signals  13   a,    13   b  of the rotation shaft actuators  14 ,  15  by using the following equations:  
         Angular Signal of Rotation Shaft Actuator  14 = A  sin (ω t )+ K    
         Angular Signal of Rotation Shaft Actuator  15 = A  sin (ω t +α)+ K    
         [0098]    (d) The rotation shaft actuators  14 ,  15  vibrate the wings  1   a,    1   b  in accordance with the angular signals  13   a,    13   b  determined in the item (c), respectively.  
         [0099]    (3) Controlling Method of Vibration Wing Controller  18   
         [0100]    (a) The vibration wing controller  28  distributes the operation command (a force and a moment which are applied to the underwater propelling apparatus) of the underwater propelling apparatus  100  to the right and left vibration wings  1 ,  1  by using a non-linear planning method, under the condition that the magnitudes and the directions of the thrusts which can be outputted from the respective vibration wings  1 ,  1  are restricted.  
         [0101]    (b) The swinging patterns for generating the forces distributed to the respective vibration wings  1 ,  1  in the item (a) are determined from the data prepared in the item (1).  
         [0102]    (c) The swinging patterns determined in the item (b) are updated for each reciprocation to control the vibration wings  1   a,    1   a,    1   b,    1   b.    
         [0103]    (4) Controlling Method of Buoyancy Controller  17   
         [0104]    The buoyancy controller  17  adjusts the buoyancy in accordance with the following procedure.  
         [0105]    (a) The buoyancy of the operation command is decomposed into the magnitude and the direction of the buoyancy.  
         [0106]    (b) Based on the direction of the buoyancy, at a time of a floating action, a draining valve  9  is opened, and a feeding value  10  is closed. At a time of a sinking action, the feeding value  10  is opened, and the draining valve  9  is closed.  
         [0107]    (c) Based on the magnitude of the buoyancy, the output of the feeding/draining pump  8  is adjusted.  
         [0108]    (d) When a flow amount of an inlet of a life buoy becomes 0 (when it becomes full or empty), the feeding/draining pump  8  is stopped.  
         [0109]    In the underwater running unit  2  having the above-mentioned vibration wing, it is possible to carry out the three-dimension control of the propelling, the rotating and the floating/sinking. That is, the plurality of wings  1   a,    1   b,  which are vibrated by the reciprocating rotations of the rotation shafts  4 ,  5  fixed to the front edge, are arranged in series. Thus, the joint control of the amplitudes, the frequencies, the vibration centers and the phases between the respective wings  1   a,    1   b  enables the plurality of sets of wings  1   a,    1   b  to be smoothly swung, such as the tail fin of the fish, as a whole, and the necessary thrust is generated, and the necessary steering operation is done. Hence, there is no risk of the enfolding of the conventional screw propeller  51 , and this is superior in silence to the screw propeller  51 .  
         [0110]    By the way, in the underwater propelling apparatus  100  of this embodiment, the number of the vibration wings  1   a,    1   b  is assumed to be  2  in one underwater running unit  2 . However, the numeral of  3  or more is naturally allowable.  
         [0111]    Also, in the underwater propelling apparatus  100 , the rotation shafts  4 ,  5  are placed in the longitudinal (vertical) direction. However, instead of that configuration, if the rotation shafts  4 ,  5  are placed in the lateral (horizontal) direction, the plurality of sets of wings  1   a,    1   b  are actuated such as a submarine rudder of the submarine boat or pectoral fins on both sides of a fish. Consequently, it is possible to change a submarine depth.  
         [0112]    Moreover, the underwater propelling apparatus  100  in this embodiment includes the tank  7  in which the water filling/draining control can be attained in particular. Thus, the tank  7  is used to adjust the buoyancy such as the life buoy of the fish. Hence, it is possible to smoothly carry out the floating/sinking control of the underwater propelling apparatus  100 .  
         [0113]    Moreover, according to the underwater propelling apparatus  100  in this embodiment, the two underwater running units  2  having the above-mentioned configuration are horizontally arranged parallel to each other. In other words, the two vibration wings  1 ,  1  are placed at the positions separated from each other on the virtual line (the virtually straight line extending in the upper and lower directions in FIG. 8, although they are not shown) substantially orthogonal to one direction X (the left side in FIG. 8) in which the fishing boat  61  or the submarine boat  62  (the propelled body) is propelled.  
         [0114]    For this reason, the stably propelling, steering, directional controlling, positional keeping functions can be attained as compared with the case of the single underwater running unit  2 . Thus, the bed unit  41  is stable. In the case of the single underwater running unit  2 , when the vibration wings  1   a,    1   b  are actuated, the underwater propelling apparatus may be rotated to thereby disable the obtainment of the stableness. In particular, if the underwater propelling apparatus  100  in this embodiment is used for the fishing boat  61 , the stableness can be used such that the position keeping function and the silence property become effective.  
         [0115]    As mentioned above with reference to FIG. 8, the two vibration wings  1 ,  1  are placed so as to be separated at the approximate separation distance longer than the width dimension in the rear of the submarine boat  62  (the propelled body) on the virtual line. Thus, the effect of the stableness becomes greater.  
         [0116]    By the way, in the underwater propelling apparatus  100  in this embodiment, the number of the vibration wings  1  is assumed to be  2 . However, the numeral of  3  or more is naturally allowable.  
         [0117]    In this case, the effect of the stableness obtained by placing the plurality of underwater running units  2 ,  2  parallel to each other can be provided even if each of the underwater running units  2  has only one vibration wing, instead of the configuration that each has the two sets of the vibration wings  1   a,    1   b  placed in series.  
         [0118]    Also, the installation of the plurality of underwater running units  2 ,  2  improves the thrust.  
         [0119]    Moreover, in the underwater propelling apparatus  100  of this embodiment, when the vibration wings  1   a,    1   b  are actuated, the vibration wing  1   b  on the tip side has the higher elastic modulus, and the envelope  2   d  has the higher flexibility than that of the envelope  2   c.  Thus, the vibration wing  1   b  on the tip side is flexed such as the lash, and it is further sharply vibrated. This enables the thrust to be effectively obtained.  
         [0120]    As mentioned above, according to the underwater propelling apparatus of the present invention, it is possible to attain the directional controlling and positional keeping functions which are further stable.