Abstract:
An actuation system includes a pump assembly configured to form a pump chamber; an actuator having first and second chambers and a movable member and configured to convert pressures applied to the first and second chambers into a movement of the movable member; and a valve section. A controller controls the valve section to open a first flow path between the pump chamber and the first chamber and close a second flow path between the pump chamber with the second chamber, during a discharge period during which the pump chamber is pressurized, in a first mode; to close the first flow path and open the second flow path during an intake period during which the pump chamber is depressurized, in the first mode; to close the first flow path and open the second flow path during the discharge period in a second mode; and to open the first flow path and close the second flow path during the intake period in the second mode.

Description:
INCORPORATION BY REFERENCE 
       [0001]    This Patent Application is based on Japanese Patent Application No. 2007-153886. The disclosure thereof is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an actuation system and a helicopter. 
         [0004]    2. Description of Related Art 
         [0005]    A helicopter has a rotary wing on an airframe thereof and is possible to perform vertical ascent and decent, forward and backward movement, and hovering. The helicopter is desired to have an improved operability.  FIG. 1  shows a rotary wing of a convention helicopter. The rotary wing  100  includes a rotor  101 , blades  102 - 1  and  102 - 2 , bearings  103 - 1  and  103 - 2 , a swash plate  104 , and a pitch change  105 . The rotor  101  is arranged in an upper portion of the airframe of the helicopter (not shown) and rotates around a rotation axis  106  with respect to the airframe. The blades  102 - i  (i=1, 2) form a wing. The bearings  103 - i  are supported by the rotor  101  and support blades  102 - i  rotatably around rotation axes  107 - i.  The swash plate  104  is supported by the rotor  101  to be movable in up and down directions along the rotation axis  106 . The pitch change  105  is connected to a part of the blade  102 - i  and a part of the swash plate  104  and maintains a distance between the part of the blades  102 - i  and the part of the swash plate  104  to be a constant. 
         [0006]    The blades  102 - i  generate a lift force when the rotor  101  rotates. That is to say, the rotary wing  100  generates propulsion of the helicopter through rotation of the rotor  101 . In this case, the swash plate  104  can be moved in the direction  108  to change the lift force of the blades  102 - i,  thereby improving the operability of the helicopter. For the helicopter, it is desired to reduce vibrations and noises more. 
         [0007]    It is known that the helicopter can reduce vibrations and noises more by driving a flap to deform an airfoil of the blades.  FIG. 2  shows a driving unit  110  for driving a flap. The driving unit  110  includes a hydraulic source  111 , a hydraulic pipe  112 , and a hydraulic cylinder  113 . The hydraulic source  111  is arranged on the airframe of the helicopter and pressurizes hydraulic fluid to generate a predetermined hydraulic pressure. The hydraulic pipe  112  transmits the hydraulic pressure from the hydraulic source  111  to the hydraulic cylinder  113  by passing the hydraulic fluid. The hydraulic cylinder  113  drives the flap  114  with the hydraulic pressure of the hydraulic fluid. In this case, in order to transmit the hydraulic pressure from the airframe to the rotating blade, a complex mechanism is required. The driving unit  110  is desired to have more simple structure and to be arranged inside the blade. 
         [0008]      FIG. 3  shows a driving unit  120  arranged inside the blade. The driving unit  120  is composed of a so-called bimorph type piezoactuator  121  made by laminating piezoelectric elements which are deformed based on applied voltage. The driving unit  120  is deformed into a form depending on a voltage applied to each of the piezoelectric elements so that a flap  122  is driven to a position. The driving unit  120  is desired to have a larger stroke (movable range). 
         [0009]    There is known a driving unit that uses a laminate type piezoactuator to enlarge the movable range by applying leverage. Such a driving unit has a small driving force compared with a bimorph type piezoactuator for which the leverage is not applied and may have a large error because of a mechanical fluctuation of the leverage. The driving unit is desired to have a strong output force and have higher precision. 
         [0010]    Japanese Laid Open Patent Application (JP-P2004-66990A) discloses a flap driving unit suitable for a unit for driving flaps provided for rotor blades. In the flap driving unit in the rotor blades, each of first and second actuator units is arranged on the rotor blade along a direction of the length of the rotor blade and has an actuator for generating a driving force the stretching and shortening. A first rotation section is provided between the first actuator unit and the second actuator unit and rotates the flaps into one direction in response to the driving force of the first actuator unit. A second rotation section is provided between the first actuator unit and the second actuator unit and rotates the flaps in another direction in response to the driving force of the second actuator unit. 
         [0011]    Japanese Laid Open Patent Application (JP-P2003-530267A) discloses a piezoelectric control apparatus for controlling flaps of a rotor blade of a helicopter, which has functionality in high level and certainty of the operation. The piezoelectric control apparatus has a piezoelectric element device including at least a laminated piezoelectric actuator and a force transmission frame connected to the piezoelectric element device. The force transmission frame is fixed on the rotor blade and generates force acting between a support member provided for the force transmission frame and a driven element in an orthogonal direction to a direction of centrifugal force of the rotor blade based on a change of a length of the piezoelectric element device when the piezoelectric element device is excited. In the piezoelectric control apparatus, a first holder allows a relative movement to the rotor blade of the force transmission frame in the orthogonal direction to the direction of centrifugal force within a limited range, and is bendable in the orthogonal direction to the direction of centrifugal force although fixing the force transmission frame on the rotor blade in the direction of centrifugal force. A second holder is bendable in the direction of centrifugal force although relatively fixing the support member provided for the force transmission frame on the rotor blade in the direction orthogonal to the direction of centrifugal force and allows a relative movement of the support member to the rotor blade of the force transmission frame in the direction of centrifugal force within a limited range. 
         [0012]    Japanese Laid Open Patent Application (JP-P2002-234499A) discloses a flap structure with a flap driving section into a rotor blade, which can adjust and maintain a flap function through inspection without almost influencing to the rotor blade. The rotor blade includes a flap and a flap driving section. A flap is provided outside the blade and the flap driving section is provided inside the blade. In the lift force generating blade, a blade chamber having an opening portion in a direction of a posterior edge of a wing is formed, and at least one casing is inserted from the opening portion and fixed to the inside of a blade chamber, and the casing incorporates at least one flap driving part and a flap. 
         [0013]    Japanese Laid Open Patent Application (JP-P2002-89453A) discloses a hydraulic pressure controlling apparatus suitable for downsizing the apparatus and reducing costs. The hydraulic pressure controlling apparatus includes a pump for performing a pumping action by reciprocating a pump piston provided in a giant-magnetostrictive material through applying a current from a power source to a coil to stretch and shorten the giant-magnetostrictive element arranged in a central portion of the coil by magnetostrictive phenomenon, and a controlled portion which operates depending on discharge pressure from the pump. The hydraulic pressure controlling apparatus includes a current detection section adapted to detect the current passing the coil of the pump; and to estimate the discharge pressure of the pump based on the current detected by the detection section. 
       SUMMARY 
       [0014]    An object of the present invention is to provide an actuation system with a smaller size and a lighter weight. 
         [0015]    Another object of the present invention is to provide an actuation system with strong output force. 
         [0016]    Still another for the present invention is to provide an actuation system with a larger range of movement. 
         [0017]    Another object of the present invention is to provide an actuation system which controls a movable member with higher precision. 
         [0018]    Another object of the present invention is to provide a helicopter applied with an actuation system to reduce noises and vibrations more. 
         [0019]    In an aspect of the present invention, an actuation system includes: a pump assembly configured to form a pump chamber; an actuator having first and second chambers and a movable member and configured to convert pressures applied to the first and second chambers into a movement of the movable member; a valve section; and a controller configured to control the valve section to open a first flow path between the pump chamber and the first chamber and close a second flow path between the pump chamber with the second chamber, during a discharge period during which the pump chamber is pressurized, in a first mode; to close the first flow path and open the second flow path during an intake period during which the pump chamber is depressurized, in the first mode; to close the first flow path and open the second flow path during the discharge period in a second mode; and to open the first flow path and close the second flow path during the intake period in the second mode. 
         [0020]    In another aspect of the present invention, a helicopter includes the actuation systems mentioned above, and a rotor wing comprising blades and configured to generate propulsion by rotating the blades. The actuation system drives a flap provided inside each of the blades, to change an airfoil of the blades. 
         [0021]    Also, in another aspect of the present invention, a helicopter includes the actuation systems mentioned above, and a rotor wing comprising blades and configured to generate propulsion by rotating the blades. The actuation system changes an orientation of each of the blades. 
         [0022]    Also, in another aspect of the present invention, a pump includes a pump assembly configured to form a pump chamber; a valve section; and a controller configured to control the valve section to open a first flow path connected with the pump chamber and close a second flow path connected the pump chamber, during a discharge period during which the pump chamber is pressurized, in a first mode; to close the first flow path and open the second flow path during an intake period during which the pump chamber is depressurized, in the first mode; to close the first flow path and open the second flow path during the discharge period in a second mode; and to open the first flow path and close the second flow path during the intake period in the second mode. 
         [0023]    In addition, in another aspect of the present invention, a control method of an actuation system, is achieved by providing an actuation system comprising a pump assembly configured to form a pump chamber, an actuator having first and second chambers and a movable member and configured to convert pressures applied to the first and second chambers into a movement of the movable member, and a valve section; by setting a first mode in which the valve section is controlled to open a first flow path between the pump and the first chamber and close a second flow path between the pump and the second chamber, during a discharge period during which the pump chamber is pressurized, and to close the first flow path and open the second flow path during an intake period during which the pump chamber is depressurized; and by setting a second mode in which the valve section is controlled to close the first flow path and open the second flow path during the discharge period in a second mode, and to open the first flow path and close the second flow path during the intake period. 
         [0024]    An actuation system according to the present invention can be designed in a smaller size and a lighter weight and is preferable to drive a flap of a blade of a helicopter and to change the orientation of the blade of the helicopter. The helicopter according to the present invention can reduce noises and vibrations more and is designed in a smaller size and a lighter weight by removing a swash plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a perspective view showing a rotary wing of a conventional helicopter; 
           [0026]      FIG. 2  is a block diagram showing a conventional driving apparatus; 
           [0027]      FIG. 3  is a section view showing a conventional driving device; 
           [0028]      FIG. 4  is a block diagram showing a helicopter according to an embodiment of the present invention; 
           [0029]      FIG. 5  is a diagram showing an actuation system with an hydraulic pressure circuit according to the embodiment of the present invention; 
           [0030]      FIG. 6  is a graph showing a change of the displacement of a piston in a giant-magnetostrictive pump; 
           [0031]      FIG. 7  is a graph showing a change of the state of a piezoelectric valve in a first mode; 
           [0032]      FIG. 8  is a graph showing a change of the state of another piezoelectric valve in the first mode; 
           [0033]      FIG. 9  is a graph showing a change of the displacement of a movable member of an actuator in the first mode; 
           [0034]      FIG. 10  is a graph showing a change of the state of the piezoelectric valve in a second mode; 
           [0035]      FIG. 11  is a graph showing a change of the state of the other piezoelectric valve in the second mode; 
           [0036]      FIG. 12  is a graph showing a change of a displacement of the movable member of the actuator in the second mode; 
           [0037]      FIG. 13  is a diagram showing the actuation system with the hydraulic pressure circuit according to another embodiment of the present invention; 
           [0038]      FIG. 14  is a graph showing the change of the displacement of the piston in the giant-magnetostrictive pump; 
           [0039]      FIG. 15  is a graph showing a change of the state of a piezoelectric switching valve in the first mode; 
           [0040]      FIG. 16  is a graph showing the change of the displacement of the movable member of the actuator in the first mode; 
           [0041]      FIG. 17  is a graph showing a change of the state of a piezoelectric switching valve in the second mode; 
           [0042]      FIG. 18  is a graph showing the change of the displacement of the movable member of the actuator in the second mode; and 
           [0043]      FIG. 19  is a perspective view showing another embodiment of the helicopter according to the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0044]    Hereinafter, a helicopter using an actuation system according to embodiments of the present invention will be described with reference to the attached drawings. In the helicopter, a rotary wing includes a plurality of blades  1  shown in  FIG. 4 . The rotary wing generates propulsion of the helicopter (for vertical ascent and descent, forward and backward movement, and hovering) according to the embodiments of the present invention by rotating the blades  1  to an airframe (not shown). The blade  1  has a cross section of an airfoil to generate lift force through the rotation of the blades  1 , and includes a flap  2  and an actuation system  3 . The flap  2  is arranged in a part of a posterior edge of the blade  1  and supported to be movable to the blade  1 . The blade  1  changes its airfoil depending on a movement of the flap  2  with respect to the blade  1 . The actuation system  3  is arranged inside the blade  1 , drives the flap  2  with respect to the blade  1 , and changes the airfoil of the blade  1 . 
         [0045]      FIG. 5  shows the actuation system  3 . The actuation system  3  includes a pump (assembly)  5  and an actuator  6 . The pump  5  is composed of a hydraulic system and a controller  7 . The hydraulic system includes a giant-magnetostrictive pump  11 , piezoelectric valves  12  and  13 , an accumulator  14 , check valves  15  and  16 , and relief valves  17  and  18 , and includes flow paths  21  to  24 . The piezoelectric valves  12  and  13 , the check valves  15  and  16 , and the relief valves  17  and  18  in the hydraulic system are arranged inside a manifold block  25 . 
         [0046]    The giant-magnetostrictive pump  11  includes a cylinder  31 , a piston  32 , a giant-magnetostrictive element  33 , and a coil  34 . The cylinder  31  has a sliding surface of a cylindrical shape. The piston  32  is arranged to internally contact the sliding surface of the cylinder  31  and inserted in the cylinder  31  to be slidable in a direction parallel to an axis of the cylinder  31 . That is to say, the giant-magnetostrictive pump  11  has a pump chamber  35  formed by the cylinder  31  and the piston  32 . The pump chamber  35  is connected to the flow paths  21 . The coil  34  converts electric energy supplied from the controller  7  into magnetic energy. The giant-magnetostrictive element  33  is deformed based on the magnetic energy generated by the coil  34 . The giant-magnetostrictive element  33  is coupled to the cylinder  31  at one end thereof and connected to the piston  32  at another end. The giant-magnetostrictive element  33  changes a capacity of the pump chamber  35  by driving the piston  32  with respect to the cylinder  31  because of the deformation. In this case, a magnitude of a drive stroke of the piston  32  is approximately 0.1 mm as an example. That is to say, the giant-magnetostrictive pump  11  is controlled by the controller  7 , and raises a hydraulic pressure in the flow path  21  or falls the hydraulic pressure in the flow path  21 . 
         [0047]    The piezoelectric valve  12  has a variable orifice between the flow path  21  and the flow path  22  and includes a piezoelectric element. The piezoelectric element is deformed based on a voltage applied by the controller  7 , to widen and narrow an opening area of the variable orifice. That is to say, the piezoelectric valve  12  is controlled by the controller  7 , connects the flow path  21  with the flow path  22  so that the hydraulic pressure can be transmitted or disconnects the flow path  21  from the flow path  22  so that the hydraulic pressure cannot be transmitted. 
         [0048]    The piezoelectric valve  13  has a variable orifice between the flow path  21  and the flow path  23  and includes a piezoelectric element. The piezoelectric element is deformed based on a voltage applied from the controller  7 , and widens and narrows an opening area of the variable orifice. That is to say, the piezoelectric valve  13  is controlled by the controller  7 , connects the flow path  21  with the flow path  23  so that the hydraulic pressure can be transmitted or disconnects the flow path  21  from the flow path  23  so that the hydraulic pressure cannot be transmitted. 
         [0049]    The accumulator  14  is provided with a container of a variable volume and a spring. The spring generates elastic force to reduce the volume of the container and maintains the hydraulic action fluid filled in the container to a predetermined hydraulic pressure. The container is connected to the flow path  24 . That is to say, the accumulator  14  maintains the hydraulic pressure in the flow path  24  to the predetermined pressure. The check valve  15  opens between the flow path  24  and the flow path  22  when the hydraulic pressure in the flow path  24  is larger than that in the flow path  22 , and closes between the flow path  24  and the flow path  22  when the hydraulic pressure in the flow path  24  is smaller than the hydraulic pressure in the flow path  22 . The check valve  16  opens between the flow path  24  and the flow path  23  when the hydraulic pressure in the flow path  24  is larger than that in the flow path  23 , and closes between the flow path  24  and the flow path  23  when the hydraulic pressure in the flow path  24  is smaller than that in the flow path  23 . That is to say, the accumulator  14 , and the check valves  15  and  16  prevent the hydraulic pressure in the flow path  22  from being smaller than the predetermined hydraulic pressure and prevent the hydraulic pressure in the flow path  23  from being smaller than the predetermined hydraulic pressure. 
         [0050]    The relief valve  17  has a predetermined pressure being set, and opens a path between the flow path  22  and the flow path  23  when the hydraulic pressure in the flow path  22  is larger than the set pressure and closes the path between the flow path  22  and the flow path  23  when the hydraulic pressure in the flow path  22  is smaller than the set pressure. That is to say, the relief valve  17  controls the hydraulic pressure in the flow path  22  so as not to be larger than the set pressure. The relief valve  18  has a predetermined pressure being set, and opens a path between the flow path  23  and the flow path  22  when the hydraulic pressure in the flow path  23  is larger than the set pressure and closes the path between the flow path  23  and the flow path  22  when the hydraulic pressure in the flow path  23  is smaller than the set pressure. That is to say, the relief valve  18  controls the hydraulic pressure in the flow path  23  so as not to be larger than the set pressure. 
         [0051]    Such a pump  5  can be designed to be smaller in size and lighter in weight, thus the actuation system  3  can be made smaller in size and lighter in weight. 
         [0052]    The actuator  6  includes a cylinder  41 , a piston  42 , and a movable member  43 . The cylinder  41  has a sliding surface in a cylindrical shape and is connected to a body of the blade  1 . The piston  42  is arranged to internally contact the sliding surface of the cylinder  41  and is inserted to be slidable in a direction parallel to an axis of the cylinder. The piston  42  divides an interior portion of the cylinder  41  into a first chamber  44  and a second chamber  45 . The first chamber  44  is connected to the flow path  22 . The second chamber  45  is connected to the flow path  23 . The movable member  43  is formed from a rigid body, a portion thereof is connected to the piston  42 , and another portion thereof is connected to the flap  2 . That is to say, the actuator  6  drives the movable member  43  to a first direction  47  when the hydraulic pressure in the flow path  22  is larger than the hydraulic pressure in the flow path  23  and drives the movable member  43  to a second direction  48  opposite to the first direction  47  when the hydraulic pressure in the flow path  22  is smaller than that in the flow path  23 . 
         [0053]    The actuation system  3  further includes a sensor  46 . The sensor  46  measures a displacement of the movable member  43  and outputs the displacement to the controller  7 . 
         [0054]    The helicopter according to the embodiment of the present invention further includes a power supply unit, a control unit, and a slip ring which are not shown. The power supply unit is arranged in the airframe of the helicopter and generates power. The control unit is arranged in the airframe of the helicopter and generates an electric signal indicating a target position of the flap  2  is operated by a pilot of the helicopter. The slip ring forms a transmission path which passes a current from the airframe side of the helicopter to the side of the blade  1 , supplies the power from the power supply unit to the controller  7  and transmits the signal from the control unit to the controller  7 . 
         [0055]    The controller  7  collects a displacement of the movable member  43  of the actuator  6  from the sensor  46 , collects a target position of the flap  2  from the control unit, and controls the actuation system  3  so that the flap  2  can be arranged on the target position. 
         [0056]    A controlling method of the actuation system according to the embodiment of the present invention is performed by the controller  7  and has a first mode, a second mode, and an operation of switching the mode. In the mode switching operation, the controller  7  changes the mode based on a displacement collected from the sensor  46  and a target position from the control unit. That is to say, the controller  7  selects the first mode when the movable member  43  of the actuator  6  needs to be driven into the first direction  47  in order to drive the flap  2  to the target position, and selects the second mode when the movable member  43  of the actuator  6  needs to be driven to the second direction  48  in order to drive the flap  2  to the target position. 
         [0057]      FIG. 6  shows a change of the displacement of the piston  32  of the giant-magnetostrictive pump  11  controlled by the controller  7  when the first mode (or the second mode) is selected. The displacement is larger when a volume of the pump chamber  35  is larger. A change  51  shows that the displacement periodically changes every a period  52 . The frequency is, for example, a hundred Hz to several hundreds Hz. The period  52  includes a discharge period  53  and an intake period  54 . The change  51  shows that its displacement monotonously reduces in the discharge period  53  and its displacement monotonously increases in the intake period  54 , namely, shows that the hydraulic pressure in the pump chamber  35  (the flow path  21 ) monotonously increases in the discharge period  53  and monotonously reduces in the intake period  54 . That is to say, the controller  7  controls the giant-magnetostrictive pump  11  so that the hydraulic pressure of the pump chamber  35  (the flow path  21 ) can monotonously increases in the discharge period  53  and monotonously reduces in the intake period  54  by supplying power to the coil  34  so that the giant-magnetostrictive element  33  can drive the piston  32 , as shown in the change  51 . 
         [0058]      FIG. 7  shows a change of the state of the piezoelectric valve  12  controlled by the controller  7  when the first mode is selected. A change  56  shows that the state periodically changes every the period  52  and shows that the state changes in synchronization with the displacement of the piston  32 . The change  56  shows that a connection between the flow path  21  and the flow path  22  is closed in the intake period  54 , the connection between the flow path  21  and the flow path  22  is opened after a predetermined time from time when the discharge period  53  starts, and the connection between the flow path  21  and the flow path  22  is closed before the discharge period  53  ends. 
         [0059]      FIG. 8  shows a change of the state of the piezoelectric valve  13  controlled by the controller  7  when the first mode is selected. The change  58  shows that the state of the piezoelectric valve  13  periodically changes every the period  52  and shows that the state of the piezoelectric valve  13  changes in synchronization with the displacement of the piston  32 . The change  58  shows that a connection between the flow path  21  and the flow path  23  is closed in the discharge period  53 , the connection between the flow path  21  and the flow path  23  is opened after a predetermined time from time when the intake period  54  starts, and the connection between the flow path  21  and the flow path  23  is closed before the intake period  54  ends. 
         [0060]    According to such an operation in the first mode, the fluid is supplied from the flow path  23  to the flow path  21  and the fluid is supplied from the flow path  21  to the flow path  22 . At this moment, the movable member  43  of the actuator  6  moves to the first direction  47  as shown in a change  59  in  FIG. 9 . 
         [0061]    When the second mode is selected, the controller  7  controls the giant-magnetostrictive pump  11  in a similar manner to a case that the first mode is selected. That is to say, a change of the displacement of the piston  32  of the giant-magnetostrictive pump  11  is same as the change  51  shown in  FIG. 6 . 
         [0062]      FIG. 10  shows a change of the state of the piezoelectric valve  12  controlled by the controller  7  when the second mode is selected. A change  61  shows that the state of the piezoelectric valve  12  periodically changes every the period  52  and shows that the state of the piezoelectric valve  12  changes in synchronization with the displacement of the piston  32 . The change  61  shows that a connection between the flow path  21  and the flow path  22  is closed in the discharge period  53 , the connection between the flow path  21  and the flow path  22  is opened after a predetermined time from time when the intake period  54  starts, and the connection between the flow path  21  and the flow path  22  is closed before the intake period  54  ends. 
         [0063]      FIG. 11  shows a change of the state of the piezoelectric valve  13  controlled by the controller  7  when the second mode is selected. A change  62  shows that the state of the piezoelectric valve  13  periodically changes every the period  52  and shows that the state of the piezoelectric valve  13  changes in synchronization with the displacement of the piston  32 . The change  62  shows that a connection between the flow path  21  and the flow path  23  is closed in the intake period  54 , the connection between the flow path  21  and the flow path  23  is opened after a predetermined time from time when the discharge period  53  starts, and the connection between the flow path  21  and the flow path  23  is closed before the discharge period  53  ends. 
         [0064]    According to such an operation in the second mode, the fluid is supplied from the flow path  22  to the flow path  21  and the fluid is supplied from the flow path  21  to the flow path  23 . At this moment, the movable member  43  of the actuator  6  moves into the second direction  48 , as shown by the change  63  in  FIG. 12 . 
         [0065]    According to the controlling method of the actuation system according to the embodiment of the present invention, the actuation system  3  can enlarge the stroke of the movable member  43  and drive the movable member  43  to a target position with higher precision, compared to a direct movement type in which the stroke is limited based on displacement amount of the giant-magnetostrictive element. 
         [0066]    It should be noted that the giant-magnetostrictive pump  11  may be replaced by another pump which does not include the giant-magnetostrictive element  33 . Such a pump is exemplified by a pump configured by replacing the giant-magnetostrictive element  33  of the giant-magnetostrictive pump  11  by a piezoelectric element. Such a pump changes the hydraulic pressure in the flow path  21  through deformation of the piezoelectric element by applying a voltage to the piezoelectric element. The giant-magnetostrictive pump  11  is preferable in that a larger hydraulic pressure can be generated, compared to the pump. 
         [0067]    In addition, it should be noted that the controlling method of the actuation system can change the frequency of the displacement of the piston  32  of the giant-magnetostrictive pump  11 . Such a change of the frequency can vary a magnitude of deformation of the giant-magnetostrictive element  33  of the giant-magnetostrictive pump  11  and reduce heat generation of the giant-magnetostrictive pump  11 . 
         [0068]    Moreover, the actuation system  3  can be employed to drive a device different from the flap  2  of the blade  1  in the helicopter. As the device, the joint of a robot is shown as an example. 
         [0069]    Furthermore, the pump  5  can be used for a purpose different from generation of a hydraulic pressure to the actuator  6 . As the purpose, conveying medical solutions for a medical treatment and conveying liquid reagents for a chemical experiment are shown as examples. 
         [0070]      FIG. 13  shows the actuation system according to another embodiment of the present invention. In an actuation system  3 ′, the pump  5  in the above-mentioned embodiment is replaced by another pump  5 ′. The pump  5 ′ is composed of a hydraulic pressure system and a controller  7 ′. The hydraulic pressure system includes a giant-magnetostrictive pump  71 , a piezoelectric switching valve  72 , an accumulator  74 , check valves  75  and  76 , and relief valves  77  and  78 , and includes flow paths  81  to  84 . The piezoelectric switching valve  72 , the check valves  75  and  76 , the relief valves  77  and  78  in the hydraulic pressure system are formed inside a manifold block  85 . 
         [0071]    The giant-magnetostrictive pump  71  is formed in similar manner as the giant-magnetostrictive pump  11  in the above described embodiment, controlled by the controller  7 ′, causes an ascent or a descent of the hydraulic pressure in the flow path  81 . 
         [0072]    The piezoelectric switching valve  72  includes a cylinder, a spool, and a piezoelectric element. The cylinder has a sliding surface in a cylindrical shape. The spool is arranged to internally contact the sliding surface of the cylinder and inserted to be slidable in a direction parallel to an axis of the cylinder. The piezoelectric element is deformed based on a voltage applied from the controller  7 ′, to drive the spool in a cylinder hollow of the cylinder. The spool can be arranged on one position selected from a neutral position, a first position, and a second position. The piezoelectric element drives the spool from the neutral position to the first position, from the neutral position to the second position, from the first position to the neutral position, and from the second position to the neutral position under the control of the controller  7 ′. 
         [0073]    The piezoelectric switching valve  72  includes a first port connected to the flow path  81 , a second port connected to the flow path  82 , and a third port connected to the flow path  83 . The cylinder and the spool form a variable orifice between the flow path  81  and the flow path  82  and form a variable orifice between the flow path  81  and the flow path  83 . The variable orifice formed between the flow path  81  and the flow path  82  is closed when the spool is arranged on the neutral position or the second position, and enlarges its opening area as the spool moves from the neutral position to the first position. The variable orifice formed between the flow path  81  and the flow path  83  is closed when the spool is arranged on the neutral position or the first position, and enlarges its opening area as the spool moves from the neutral position to the second position. 
         [0074]    The piezoelectric switching valve  72  is preferable in prevention of the flow path  82  and the flow path  83  from connecting to each other, compared to the piezoelectric valve  12  and the piezoelectric valve  13  in the above-described embodiment. 
         [0075]    The accumulator  74  maintains a hydraulic pressure in the flow path  84  to a predetermined pressure in a same manner as the accumulator  14  in the above-described embodiment. The check valve  75  opens between the flow path  84  and the flow path  82  when the hydraulic pressure in the flow path  84  is larger than that in the flow path  82 , and closes between the flow path  84  and the flow path  82  when the hydraulic pressure in the flow path  84  is smaller than that in the flow path  82 . The check valve  76  opens between the flow path  84  and the flow path  83  when the hydraulic pressure in the flow path  84  is larger than that in the flow path  83 , and closes between the flow path  84  and the flow path  83  when the hydraulic pressure in the flow path  84  is smaller than that in the flow path  83 . That is to say, the accumulator  74 , and the check valves  75  and  76  prevent the hydraulic pressure in the flow path  82  from being smaller than the predetermined hydraulic pressure and prevent the hydraulic pressure in the flow path  83  from being smaller than the predetermined hydraulic pressure. 
         [0076]    The relief valve  77  is set to a predetermined pressure, and opens between the flow path  82  and the flow path  83  when the hydraulic pressure in the flow path  82  is larger than the set pressure and closes between the flow path  82  and the flow path  83  when the hydraulic pressure in the flow path  82  is smaller than the set pressure. That is to say, the relief valve  77  controls the hydraulic pressure in the flow path  82  not to become larger than the set pressure. The relief valve  78  is set to a predetermined pressure, and opens between the flow path  83  and the flow path  82  when the hydraulic pressure in the flow path  83  is larger than the set pressure and closes between the flow path  83  and the flow path  82  when the hydraulic pressure in the flow path  83  is smaller than the set pressure. That is to say, the relief valve  78  controls the hydraulic pressure in the flow path  83  not to be larger than the set pressure. 
         [0077]    The actuation system  3 ′ further includes a sensor  86 . The sensor  86  measures a position of the spool in the piezoelectric switching valve  72  and outputs the position to the controller  7 ′. 
         [0078]    The controller  7 ′ collects the displacement of the movable member  43  in the actuator  6  from the sensor  46 , collects the target position of the flap  2  from the control unit, collects the position of the spool in the piezoelectric switching valve  72  from the sensor  86 , and controls the actuation system  3 ′ so that the flap  2  can be arranged on the target position. 
         [0079]    A controlling method of the actuation system according to another embodiment of the present invention is performed by the controller  7 ′ and has a first mode, a second mode and an operation switching mode. In an operation switching mode, the controller  7 ′ switches the mode based on the displacement collected from the sensor  46  and the target position collected from the control unit. That is to say, the controller  7 ′ selects the first mode when the movable member  43  of the actuator  6  needs to be driven to the first direction  47  in order to drive the flap  2  to the target position, and selects the second mode when the movable member  43  of the actuator  6  needs to be driven to the second direction  48  in order to drive the flap  2  to the target position. 
         [0080]      FIG. 14  shows a change of the displacement of the piston of the giant-magnetostrictive pump  71  controlled by the controller  7 ′ when the first mode (or the second mode) is selected. An increase of the displacement shows that the giant-magnetostrictive pump  71  increases the hydraulic pressure in the flow path  81  and a decrease of the displacement shows that the giant-magnetostrictive pump  71  decreases the hydraulic pressure in the flow path  81 . A change  91  shows that the displacement periodically changes every a period  92 . The period  92  includes a discharge period  93 , an intake period  94 , and a suspended period  95 . The change  91  shows that the displacement monotonously reduces in the discharge period  93 , the displacement monotonously increases in the intake period  94 , and the displacement is constant in the suspended period  95 . That is to say, the change  91  shows that the hydraulic pressure in the flow path  81  monotonously increases in the discharge period  93 , monotonously decreases in the intake period  94 , and is constant on the suspended period  95 . That is to say, the controller  7 ′ controls the giant-magnetostrictive pump  71  so that the hydraulic pressure in the flow path  81  can monotonously increase in the discharge period  93 , monotonously decrease in the intake period  94 , and be constant on the suspended period  95 , as shown in the change  91 . 
         [0081]      FIG. 15  shows a change of the position of the spool of the piezoelectric switching valve  72  controlled by the controller  7 ′ when the first mode is selected. The change  96  shows that the state of the spool periodically changes every the period  92  and that the state of the spool changes in synchronization with the displacement of the piston of the giant-magnetostrictive pump  71 . The change  96  shows that the spool is arranged on the neutral position in the suspended period  95 , that the spool is driven to the first position after a predetermined time from time when the discharge period  93  starts, that the spool is driven to the neutral position before the discharge period  93  ends, that the spool is driven to the second position after a predetermined time from time when the discharge period  94  starts, and that the spool is driven to the neutral position before the discharge period  94  ends. 
         [0082]    According to such an operation of the first mode, the hydraulic action fluid is supplied from the flow path  83  to the flow path  81  and the hydraulic action fluid is supplied from the flow path  81  to the flow path  82 . At this moment, the movable member  43  of the actuator  6  moves to the first direction  47 , as shown in the change  97  in  FIG. 16 . 
         [0083]    When the second mode is selected, the controller  7 ′ controls the giant-magnetostrictive pump  71  in the same manner when the first mode is selected. That is to say, a change of the displacement of the piston of the giant-magnetostrictive pump  71  is equal to the change  91  shown in  FIG. 14 . 
         [0084]      FIG. 17  shows a change of a position of the spool of the piezoelectric switching valve  72  controlled by the controller  7 ′ when the second mode is selected. The change  98  shows that the state of the spool periodically changes every the period  92  and that the state of the spool changes in synchronization with the displacement of the piston of the giant-magnetostrictive pump  71 . The change  98  shows that the spool is arranged on the neutral position in the suspended period  95 , that the spool is driven to the second position after a predetermined time from time when the discharge period  93  starts, that the spool is driven to the neutral position before the discharge period  93  ends, that the spool is driven to the first position after a predetermined time from time when the discharge period  94  starts, and that the spool is driven to the neutral position before the discharge period  94  ends. 
         [0085]    According to such an operation of the second mode, the hydraulic action fluid is supplied from the flow path  82  to the flow path  81  and the hydraulic action fluid is supplied from the flow path  81  to the flow path  83 . At this moment, the movable member  43  of the actuator  6  moves to the second direction  48 , as shown in the change  99  in  FIG. 18 . 
         [0086]    According to the controlling method of the actuation system according to the embodiment of the present invention, the actuation system  3 ′ can enlarge the stroke of the movable member  43  and drive the movable member  43  to a target position with higher precision in a similar manner as the controlling method of the actuation system in the above described embodiment. Furthermore, the controlling method of the actuation system can reduce heat generation of the giant-magnetostrictive pump  71  by providing the suspended period  95  during which the giant-magnetostrictive element of the giant-magnetostrictive pump  71  is not deformed. 
         [0087]    In the helicopter according to the embodiment of the present invention, a rotary wing is provided for an airframe. As shown in  FIG. 19 , the rotary wing  200  includes a rotor  201 , blades  202 - 1  to  202 - 2 , and bearings  203 - 1  to  203 - 2 , and includes the actuation system  3  in the above described embodiment. The rotor  201  is arranged in an upper portion of the airframe (not shown) of the helicopter and rotates around a rotation axis  206  of the airframe. The blades  202 - i  (i=1, 2) constitute a wing. The bearings  203 - i  are supported by the rotor  201  and support the blades  202 - i  rotatably around the rotation axes  207 - i.  The actuation system  3  is supported by the rotor  201  or a plate instead of a swash plate. 
         [0088]    The helicopter according to the embodiment of the present invention further includes a power supply unit, a control unit, and a slip ring which are not shown. The power supply unit is arranged in the airframe of the helicopter to generate power. The control unit is arranged in the airframe of the helicopter and is operated by a pilot of the helicopter to generate an electric signal indicating a target angle of the blade  202 - i.  The slip ring forms a transmission path which passes current from the airframe side of the helicopter to the side of the rotor  201 , supplies the power from the power supply unit to the actuation system  3 , and transmits the electric signal from the control unit to the actuation system  3 . 
         [0089]    The actuation system  3  collects a target angle of the blade  202 - i  from the control unit, and changes the orientation of the blades  202 - i  so that the blades  202 - i  can be set to the target angle. In addition, the actuation system  3  can be replaced by the actuation system  3 ′ in the above described embodiment. 
         [0090]    Such a helicopter can remove the swash plate for changing the orientation of the blades  202 - 1  to  202 - 2 , and it is preferable. 
         [0091]    In addition, the actuation system  3  can be arranged on another position. As the position, an inside of the blade  202 - i  is shown as an example. 
         [0092]    It should be noted that the actuation system  3  can be supported by the swash plate (not shown). The swash plate is supported by the rotor  201  in parallel to the rotation axis  201  and is movable in parallel. In this case, the swash plate can switch pitch angles of the blades  202 - 1  to  202 - 2  by parallel moving is operated by a pilot of the helicopter. The helicopter described above is further preferable in that pitch angles of the blades  202 - 1  to  202 - 2  can be changed by both the swash plate and the actuation system  3 , a controllability of the helicopter is improved, and noises and vibrations are reduced. 
         [0093]    In addition, the blades  202 - 1  to  202 - 2  can include the flap  2  and the actuation system  3  in a similar manner as the blade  1  in the above-described embodiment. The helicopter described above is further preferable in the improvement of the controllability of the helicopter, the reduction of noises and vibrations, and downsizing and weight reducing.