Patent Publication Number: US-2023135138-A1

Title: Vr training system for aircraft, vr training method for aircraft, and vr training program for aircraft

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a bypass continuation of International Application No. PCT/JP2021/024239, filed Jun. 25, 2021, which claims priority to JP 2020-110967, filed Jun. 26, 2020, each of which are incorporated by reference in their entirety. 
    
    
     FIELD 
     The technique disclosed here relates to an aircraft VR training system, an aircraft VR training method, and an aircraft VR training program. 
     BACKGROUND 
     With a known system, users perform VR experience in common virtual reality (VR) space. Japanese Patent Application Publication No. 2019-80743, for example, discloses a system with which players play a game in common VR space. In this system, one terminal tracks players in real space and generates operation characters associated with the players in the VR space. 
     SUMMARY 
     An aircraft VR training system disclosed here includes: training terminals that generates simulation images for simulation training in common VR space and provides the simulation images to trainees individually associated with the training terminals; and a tracking sensor that detects motion of the trainees in real space, wherein each of the training terminals calculates a position and a posture of a self avatar in the VR space based on a detection result of the tracking sensor, the self avatar being an avatar of the trainee associated with the each of the training terminals, and acquires position information on a position and a posture of another avatar associated with another training terminal of the training terminals in the VR space from the another training terminal, and generates the another avatar in the VR space based on the acquired position information of the another avatar. 
     An aircraft VR training method disclosed here is an aircraft VR training method for simulation training in which trainees individually associated with training terminals use simulation images in common VR space generated by the training terminals, and the aircraft VR training method includes: calculating, by each of the training terminals, a position and a posture of a self avatar that is an avatar of one of the trainees associated with the each of the training terminals in the VR space based on a detection result of a tracking sensor that detects motion of the one of the trainees in real space; and acquiring, by each of the training terminals, position information on a position and a posture of another avatar that is an avatar of another one of the trainees associated with another training terminal of the training terminals in the VR space from the another training terminal, and to generate the another avatar in the VR space based on the acquired position information of the another avatar. 
     An aircraft VR training program disclosed here is an aircraft VR training program for causing a computer of each of training terminals to execute the function of generating simulation images for simulation training in common VR space and of providing the simulation images to trainees individually associated with the each of the training terminals, and the aircraft VR training program causing the computer to execute the functions of: calculating a position and a posture of a self avatar that is an avatar of an associated one of the trainees in the VR space based on a detection result of a tracking sensor that detects motion of the one of the trainees in real space; and acquiring position information on a position and a posture of another avatar that is an avatar of one of the trainees associated with another training terminal of the training terminals in the VR space from the another training terminal, and generating the another avatar in the VR space based on the acquired position information of the another avatar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view illustrating a configuration of a VR training system. 
         FIG.  2    is a schematic drawing illustrating real space where training is performed using the VR training system. 
         FIG.  3    illustrates an example of a helicopter created in VR space. 
         FIG.  4    is a block diagram of training terminals of a pilot and a copilot and peripheral equipment thereof. 
         FIG.  5    is a block diagram of training terminals of a hoist operator and a descender and peripheral equipment thereof. 
         FIG.  6    is a block diagram of a setting terminal and peripheral equipment thereof. 
         FIG.  7    is a flowchart of a pilot training process of a training terminal of a pilot. 
         FIG.  8    is a flowchart of a pilot training process of a training terminal of a trainee other than the pilot. 
         FIG.  9    is an example of VR space generated by a training terminal of a hoist operator when a self avatar is displayed. 
         FIG.  10    is an example of VR space generated by the training terminal of the hoist operator when another avatar is displayed. 
         FIG.  11    is an example of VR space generated by the training terminal of the hoist operator when positions and postures of the self avatar, other avatars, and an airframe are updated. 
         FIG.  12    is a flowchart showing a flow of trainings in simulation training. 
         FIG.  13    is an example of a simulation image of a hoist operator in flight training. 
         FIG.  14    is an example of a simulation image of the hoist operator or a descender in descent training. 
         FIG.  15    is an example of a simulation image of a descender in descent training. 
         FIG.  16    is a view illustrating an example of a layout situation in VR space in descent training. 
         FIG.  17    is an example of a simulation image of a copilot in descent training. 
         FIG.  18    is an example of a simulation image of the hoist operator in descent training. 
         FIG.  19    is an example of a simulation image of the descender in rescue training. 
         FIG.  20    is an example of a simulation image of the descender in rescue training. 
         FIG.  21    is an example of a simulation image of the descender in pull-up training. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An exemplary embodiment will be described in detail hereinafter with reference to the drawings.  FIG.  1    is a view illustrating a configuration of a VR training system  100 .  FIG.  2    is a schematic drawing illustrating real space where training is performed using the VR training system  100 .  FIG.  2    does not show terminals. 
     The VR training system  100  is a system for performing simulation training (hereinafter referred to as “VR training”) in common VR space. The VR training system  100  is used for VR training with an aircraft (helicopter in this example). The VR training system  100  generates a simulation image for performing simulation training in common VR space, and includes training terminals  1  that provides a simulation image to associated trainees  9  and a setting terminal  6  having setting information necessary for generating the simulation image. The simulation image is an image forming VR space, and is a so-called VR image. The simulation image includes avatars of the trainees  9  and an airframe of the aircraft. 
     The training terminals  1  are communicably connected to each other. The training terminals  1  are communicably connected to the setting terminal  6 . These terminals are connected to each other by wires through a LAN or the like. The terminals may be wirelessly connected to each other. 
     The simulation training is cooperative training by the trainees  9  respectively associated with the training terminals  1 . In this example, the trainees  9  perform cooperative training with a rescue helicopter in common VR space by using the VR training system  100 . The trainees  9  include, for example, a pilot  91 , a copilot  92 , a hoist operator  93 , and a descender  94 . When the trainees are not distinguished from each other, these trainees will be hereinafter referred to simply as “trainees  9 .” The cooperative training is training performed by the trainees  9  in cooperation. For example, the cooperative training is training in which the trainees  9  operate a helicopter to a point where a rescue requester is present and rescue the rescue requester. The cooperative training includes flight of the helicopter by the pilot  91  from a start point to a place of the rescue requester, piloting assist and safety check by, for example, the copilot  92  during flight, and descending and pull-up by the hoist operator  93  and the descender  94 . 
       FIG.  3    illustrates an example of the helicopter created in VR space. For example, a helicopter  8  includes an airframe  80 , a boom  81  extending from an upper portion of the airframe  80  to the right or left in a cantilever manner, a hoist cable  82  hung from the boom  81 , a rescue band  83  coupled to the hoist cable  82 , a hoisting machine  84  for hoisting the hoist cable  82 , and a pendant-type operator for operating the hoisting machine  84 . A pilot avatar  91 A of the pilot  91 , a copilot avatar  92 A of the copilot  92 , and a hoist operator avatar  93 A of the hoist operator  93  are disposed in the airframe  80 . A descender avatar of the descender  94  is basically disposed in the airframe  80   
     The training terminals  1  is terminals for the trainees  9 . One training terminal  1  is allocated to each trainee  9 . Each training terminal  1  generates a simulation image for an associated trainee  9 . For example, each training terminal  1  generates a simulation image from a first-person viewpoint of the associated trainee  9 . That is, the training terminals  1  generate simulation images from different viewpoints in the common VR space. In this example, four training terminals  1  for four trainees  9  are provided. 
     A VR display device  2  is connected to each of the training terminals  1 . The VR display device  2  displays a simulation image generated by the training terminal  1 . The VR display device  2  is mounted on the head of the trainee  9 . The VR display device  2  is, for example, a head mounted display (HMD). The HMD may be a goggle-shaped device having a display and dedicated for VR, or may be configured by attaching a smartphone or a portable game device to a holder mountable on the head. The VR display device  2  displays a three-dimensional image including an image for the right eye and an image for the left eye. The VR display device  2  may include a headphone  28  and a microphone  29 . Each trainee  9  has a conversation with other trainees  9  through the headphone  28  and the microphone  29 . The trainee  9  can listen to sound necessary for simulation through the headphone  28 . 
     The VR training system  100  also includes operation devices to be used by the trainees  9  in simulation training The trainees  9  operate the operation devices depending on training contents. The operation devices are appropriately changed depending on the operation contents of the trainees  9 . For example, the VR training system  100  includes a piloting device  3 A for the pilot  91  and a piloting device  3 A for the copilot  92 . The VR training system  100  includes two controllers  3 B for the hoist operator  93  and two controllers  3 B for the descender  94 . 
     The piloting devices  3 A are operated by the trainees  9  who pilot an aircraft in the trainees  9 , that is, the pilot  91  or the copilot  92 . The piloting devices  3 A receive an operation input from the pilot  91  or the copilot  92 . Specifically, each piloting device  3 A includes a control stick  31 , pedals  32 , and a collective pitch lever  33  (hereinafter referred to as a “CP lever  33 ”). Each of the control stick  31 , the pedals  32 , and the CP lever  33  has a sensor for detecting the amount of operation. Each sensor outputs an operation signal in accordance with the amount of operation. Each piloting device  3 A further includes a seat  34 . The pilot  91  or the copilot  92  operates the piloting device  3 A so that the location and posture of the aircraft in the simulation image, specifically the helicopter  8 , is thereby changed. The piloting devices  3 A are connected to an airframe calculating terminal  5 . That is, operation signals from the control stick  31 , the pedals  32 , and the CP lever  33  are input to the airframe calculating terminal  5 . 
     The airframe calculating terminal  5  calculates the amount of movement and the amount of change of posture of the aircraft airframe based on the operation input through the piloting devices  3 A. The airframe calculating terminal  5  is included in the VR training system  100  in order to reduce calculation loads of the training terminals  1 . The airframe calculating terminal  5  is communicably connected to each of the training terminals  1  and the setting terminal  6 . The airframe calculating terminal  5  is connected to the training terminals  1  and the setting terminal  6  by wires through a LAN, for example. The airframe calculating terminal  5  may be wirelessly connected to the training terminals  1  and the setting terminal  6 . 
     The airframe calculating terminal  5  transmits movement amount information on the amount of movement and the amount of change of posture of the airframe to at least one of the training terminal  1  of the pilot  91  or the training terminal  1  of the copilot  92 . The training terminal  1  that has received the movement amount information calculates a position and a posture of the airframe  80  in the VR space based on the movement amount information. That is, the airframe calculating terminal  5  and the training terminal  1  receiving the movement amount information configure an airframe terminal  50  that calculates a position and a posture of the airframe  80  of the aircraft in the VR space based on an operation input through the piloting device  3 A. 
     The controllers  3 B are portable devices. Each of the trainees  9  (i.e., the hoist operator  93  and the descender  94 ) carries the controllers  3 B with the right hand and the left hand, respectively. Each of the controllers  3 B has a motion tracker function. That is, the controllers  3 B are sensed by a tracking system  4  described later. Each of the controllers  3 B includes an operation switch  35  (see  FIG.  5   ) that receives an input from the trainee  9 . The operation switch  35  outputs an operation signal in response to the input from the trainee  9 . The controller  3 B is connected to the training terminal  1  of the hoist operator  93  or the descender  94 . That is, an operation signal from the operation switch  35  is input to the training terminal  1  of the associated hoist operator  93  or descender  94 . 
     The setting terminal  6  receives an input of setting information from an administrator (e.g., instructor) authorized to perform initial setting. The setting terminal  6  sets the input setting information as initial setting. The setting terminal  6  transmits the setting information to the training terminals  1 , and also transmits start notification of simulation training to the training terminals  1 . The setting terminal  6  displays a simulation image in training. It should be noted that in this embodiment, the setting terminal  6  generates no simulation image. The setting terminal  6  obtains and displays simulation images generated by the training terminals  1 . Accordingly, a person (e.g., instructor) other than the trainees  9  can monitor simulation of training. The setting terminal  6  may obtain information from the training terminals  1  and generate a simulation image of each trainee  9 . 
     The VR training system  100  also includes the tracking system  4 . The tracking system  4  detects motions of the trainees  9  in the real space. The tracking system  4  senses the VR display device  2  and the controllers  3 B. The tracking system  4  is an outside-in tracking system in this example. 
     Specifically, the tracking system  4  includes tracking sensors  41 , and a communication device  42  (see  FIGS.  4  and  5   ) that receives signals from the tracking sensors  41 . The tracking sensors  41  are, for example, cameras. The tracking sensors  41  are disposed to take pictures of real space including the trainees  9  in stereo. Each of the VR display device  2  and the controllers  3 B has a luminescent tracking marker. The tracking sensors  41  take photographs of tracking markers of the VR display device  2  and the controllers  3 B in stereo. 
     The tracking system  4  are common to the trainees  9 . That is, the common tracking system  4  senses, that is, tracks, the VR display devices  2  and the controllers  3 B of the trainees  9 . 
     Image data taken by the tracking sensors  41  is transmitted to the communication device  42 . The communication device  42  transmits the received image data to the training terminals  1 . The communication device  42  is, for example, a cable modem, a soft modem, or a wireless modem. 
     Each of the training terminals  1  obtains a position and a posture of an avatar of the associated trainee  9  in the VR space by performing image processing on the image data from the tracking system  4 . 
     In addition, each of the training terminals  1  of the hoist operator  93  and the descender  94  performs data processing on the image data from the tracking system  4  to thereby obtain positions and postures of the hands of the avatar of the associated trainee  9  in the VR space based on the tracking markers of the controllers  3 B of the associated trainee  9 . 
       FIG.  4    is a block diagram of the training terminals  1  of the pilot  91  and the copilot  92  and peripheral equipment thereof. 
     The training terminals  1  of the pilot  91  and the copilot  92  are connected to the VR display device  2 , the airframe calculating terminal  5 , and the tracking system  4 . The piloting devices  3 A are connected to the airframe calculating terminal  5 . 
     Each of the training terminals  1  includes an inputter  11 , a communicator  12 , a memory  13 , and a processor  14 . 
     The inputter  11  receives operation inputs from the trainee  9 . The inputter  11  outputs an input signal in accordance with the operation input to the processor  14 . For example, the inputter  11  is a keyboard, a mouse, or a touch panel operated by pressing a liquid crystal screen or the like. 
     The communicator  12  is an interface that communicates with, for example, other terminals. For example, the communicator  12  is formed by a cable modem, a soft modem, or a wireless modem. A communicator  22 , a communicator  51 , and a communicator  63  described later are also configured in a manner similar to the communicator  12 . The communicator  12  implements communication with other terminals, such as other training terminals  1 , the airframe calculating terminal  5 , and the setting terminal  6 . 
     The memory  13  is a storage medium that stores programs and various types of data and is readable by a computer. The memory  13  is formed by a magnetic disk such as a hard disk, an optical disk such as a CD-ROM or a DVD, or a semiconductor memory. A memory  52  and a memory  64  described later are configured in a manner similar to the memory  13 . 
     The memory  13  stores a simulation program  131 , field definition data  132 , avatar definition data  133 , object definition data  134 , and sound data  135 , for example. 
     The simulation program  131  is a program for causing a computer, that is, the processor  14 , to implement the functions of generating a simulation image for simulation training in the common VR space and providing the simulation image to the associated trainee  9 . The simulation program  131  is read and executed by the processor  14 . 
     The field definition data  132  defines a field where training is performed. For example, the field definition data  132  defines a range of the field, a geographic features of the field, and objects such as an obstacle in the field. The field definition data  132  is prepared for each type of field where training is performed. 
     The avatar definition data  133  defines an avatar of a self (hereinafter referred to as a “self avatar”) and an avatar of other trainees  9  (hereinafter referred to as “other avatars or another avatar”). The avatar definition data  133  is prepared for each type of avatar. The avatar definition data  133  of the self avatar includes not only CG data (e.g., polygon data) of the self avatar but also initial position information (information on an initial position and an initial posture in the VR space). 
     The position information (including initial position information) of an avatar herein includes position coordinates (x, y, z) of three orthogonal axes in the VR space as positional information, and includes rotation angles (Φ, θ, ψ) about the axes as posture information. The same holds for position information of an object such as the airframe  80  of the helicopter  8  described later. 
     The object definition data  134  defines objects necessary for training. The object definition data  134  is prepared for each type of object. For example, the object definition data  134  is prepared for the airframe  80  of the helicopter  8 , the boom  81 , the hoist cable  82 , the rescue band  83 , the hoisting machine  84 , the pendant-type operator, a rescue requester  88 , the ground surface, and so forth. 
     The sound data  135  is data on sound effects such as flight sound of a helicopter during simulation. 
     The processor  14  includes processors such as a central processing unit (CPU), a graphics processing unit (GPU), and/or a digital signal processor (DSP), and semiconductor memories such as a VRAM, a RAM, and/or a ROM. A processor  25 , a processor  53 , and a processor  65  are configured in a manner similar to the processor  14 . 
     The processor  14  reads and executes programs stored in the memory  13  to thereby collectively control parts of the training terminals  1  and implement functions for providing simulation images. Specifically, the processor  14  includes a communication controller  141 , a setter  142 , a tracking controller  144 , a sound generator  145 , and a simulation progressor  146  as functional blocks. 
     The communication controller  141  performs a communication process with an external terminal or a device through the communicator  12 . The communication controller  141  performs data processing on data communication. 
     The setter  142  receives setting information on generation of the simulation image from the setting terminal  6 , and sets setting information. The setter  142  sets various types of setting information as initial setting. 
     The tracking controller  144  calculates a position and a posture of a self avatar that is an avatar of the associated trainee  9  in the VR space based on a detection result of the tracking system  4 . The tracking controller  144  performs various calculation processes regarding tracking based on image data from the tracking sensors  41  input through the communication device  42 . Specifically, the tracking controller  144  performs image processing on the image data to thereby track the tracking marker of the VR display device  2  of the associated trainee  9  and obtain the position and the posture of the trainee  9  in the real space. From the position and the posture of the trainee  9  in the real space, the tracking controller  144  obtains a position and a posture of the self avatar in the VR space based on a predetermined coordinate relationship. Information on the position and the posture of the self avatar in the VR space obtained by the tracking controller  144  will be referred to as position information. The “position and the posture of the avatar” and ““the position of the avatar” will be hereinafter referred to as the “position and the posture in the VR space” and “the position in the VR space,” respectively. 
     The sound generator  145  reads the sound data  135  from the memory  13 , generates produces sound in accordance with progress of simulation. 
     The simulation progressor  146  performs various calculation processes regarding progress of simulation. For example, the simulation progressor  146  generates a simulation image. The simulation progressor  146  reads the field definition data  132  and the object definition data  134  from the memory  13  based on initial setting of the setter  142 , and generates a simulation image obtained by synthesizing an object image on a field image. 
     The simulation progressor  146  reads the avatar definition data  133  associated with the self avatar from the memory  13 , and synthesizes self avatar (e.g., hands and feet of the self avatar) on the VR space based on position information of the self avatar, thereby generating a simulation image. Regarding the self avatars of the pilot  91  and the copilot  92 , a state in which the self avatars are seated on a pilot&#39;s seat and a copilot&#39;s seat in the VR space may be maintained. That is, in the simulation image, the positions of the self avatars of the pilot  91  and the copilot  92  in the airframe  80  are fixed, and only the heads of the self avatars may be operated (rotated and tilted). In this case, the simulation progressors  146  of the training terminals  1  of the pilot  91  and the copilot  92  may not generate images of the self avatars. 
     In addition, the simulation progressor  146  acquires position information of other avatars that are avatars of the trainees  9  associated with other training terminals  1  in the training terminals  1  from the other training terminals  1 , and based on the acquired position information, produces the other avatars in the VR space. Specifically, the simulation progressor  146  reads the avatar definition data  133  associated with the other avatars from the memory  13  and, based on the position information of the other avatars acquired from the other training terminals  1 , syntheses the other avatars on the VR space to thereby generate a simulation image. 
     The simulation progressor  146  receives start notification of simulation training from the setting terminal  6 , and starts simulation training. That is, the simulation progressor  146  starts training in the simulation image. The simulation progressor  146  controls progress of simulation of cooperative training during simulation training. 
     Specifically, the simulation progressor  146  calculates a position of a posture of the airframe  80  in the VR space based on movement amount information from the airframe calculating terminal  5  described later (information on the amount of movement and the amount of change of posture of the airframe in response to an operation input of the piloting device  3 A). The simulation progressor  146  converts the amount of movement and the amount of change of posture of the airframe from the airframe calculating terminal  5  to the amount of movement and the amount of change of posture of the airframe  80  in a coordinate system of the VR space, and calculates a position and a posture of the airframe  80  in the VR space. Accordingly, in accordance with the operation inputs from the piloting devices  3 A, the helicopter  8  moves, that is, flies, in the VR space. 
     The calculation of the position and the posture of the airframe  80  in the VR space is executed by one of the training terminals  1  of the pilot  91  and the copilot  92  in which the piloting function of the airframe is effective. Which one of the training terminals  1  of the pilot  91  and the copilot  92  in which the piloting function is effective is switchable. In general, the piloting function of the training terminal  1  of the pilot  91  is set to be effective. In some cases, the piloting function of the training terminal  1  of the copilot  92  is set to be effective depending on the training situation. 
     The simulation progressor  146  causes the self avatar to operate in the VR space based on position information from the tracking controller  144 , and causes other avatars to operate in the VR space based on position information of the other avatars received from the other training terminals  1 . In a case where the self avatars of the pilot  91  and the copilot  92  are fixed at the pilot&#39;s seat and the copilot&#39;s seat in the VR space, only the heads of the self avatars move (turn and tilt). It should be noted that the self avatars of the pilot  91  and the copilot  92  do not necessarily move only in the heads, and may move in the VR space based on position information from the tracking controller  144  in a manner similar to the other avatars. 
     In addition, the simulation progressor  146  changes a position or an angle of a frame of a simulation image to be displayed in accordance with the change of orientation of the head of the pilot  91  or the copilot  92  based on position information from the tracking controller  144 . The simulation progressor  146  outputs the generated simulation image to the VR display device  2  and the setting terminal  6 . At this time, the simulation progressor  146  outputs sound generated by the sound generator  145  to the headphone  28  and the setting terminal  6  when necessary. 
     The VR display device  2  includes an inputter  21 , the communicator  22 , a memory  23 , a display  24 , and a processor  25 . 
     The inputter  21  receives an operation input from the trainee  9 . The inputter  21  outputs an input signal in accordance with an operation input to the processor  25 . For example, the inputter  21  is an operation button or a slide switch. 
     The communicator  22  is an interface that implements communication with the training terminal  1 . 
     The memory  23  is a storage medium that stores programs and various types of data and is readable by a computer. The memory  23  is, for example, a semiconductor memory. The memory  23  stores programs and various types of data for causing a computer, that is, the processor  25 , to implement functions for displaying a simulation image on the display  24 . 
     The display  24  is, for example, a liquid crystal display or an organic EL display. The display  24  can display an image for the right eye and an image for the left eye. 
     The processor  25  reads and executes programs stored in the memory  23  to thereby collectively control parts of the VR display device  2  and implement functions for causing the display  24  to display a simulation image. 
     The airframe calculating terminal  5  includes the communicator  51 , the memory  52 , and the processor  53 . The airframe calculating terminal  5  receives operation signals output from the piloting devices  3 A. Specifically, each of the control stick  31 , the pedals  32 , and the CP lever  33  inputs an operation signal in accordance with the amount of depression and the amount of operation of the switch. The airframe calculating terminal  5  calculates the amount of movement and the amount of change of posture of the airframe in accordance with the amount of operation of the piloting device  3 A, and outputs movement amount information. 
     The communicator  51  is an interface that implements communication with, for example, the training terminal  1 . 
     The memory  52  stores, for example, a calculation program  521 . The calculation program  521  is a program for causing a computer, that is, the processor  53 , to implement functions for calculating a position and a posture of the airframe  80  of the aircraft in the VR space. The calculation program  521  is read out and executed by the processor  53 . 
     The processor  53  reads and executes programs stored in the memory  52  to thereby collectively control parts of the airframe calculating terminal  5  and implement functions for calculating the amount of movement and the amount of change of posture of the airframe. Specifically, the processor  53  includes a communication controller  531  and an airframe calculator  532  as functional blocks. 
     The communication controller  531  executes a communication process with, for example, the training terminal  1  through the communicator  51 . The communication controller  531  executes data processing on data communication. 
     The airframe calculator  532  calculates the amount of movement and the amount of change of posture of the airframe based on operation signals from the piloting devices  3 A. Specifically, based on operation signals from the control stick  31 , the pedals  32 , and the CP lever  33 , the airframe calculator  532  calculates the amount of movement and the amount of change of posture of the airframe in accordance with the amounts of depression and the amounts of operation of the switches of the control stick  31 , the pedals  32 , and the CP lever  33 . The airframe calculator  532  transmits movement amount information on the calculated amount of movement and the calculated amount of change of posture of the airframe to the training terminal  1 . 
       FIG.  5    is a block diagram of the training terminals  1  of the hoist operator  93  and the descender  94  and peripheral equipment thereof. 
     The training terminals  1  of the hoist operator  93  and the descender  94  are connected to the VR display device  2 , the controllers  3 B, and the tracking system  4 . Each of the controllers  3 B includes an operation switch  35 . Operation signals of the operation switches  35  are input to the training terminals  1 . 
     Basic configurations of the training terminals  1  of the hoist operator  93  and the descender  94  are similar to those of the training terminals  1  of the pilot  91  and the copilot  92 . It should be noted that processing in the training terminals  1  of the hoist operator  93  and the descender  94  is slightly different from processing in the training terminals  1  of the pilot  91  and the copilot  92  due to the difference in training between the group of the hoist operator  93  and the descender  94  and the group of the pilot  91  and the copilot  92 . 
     Specifically, the tracking controller  144  calculates a position and a posture of the self avatar that is an avatar of the associated trainee  9  in the VR space based on a detection result of the tracking system  4 . The tracking controller  144  performs various calculation processes regarding tracking based on image data from the tracking sensors  41  input through the communication device  42 . Specifically, the tracking controller  144  performs image processing on the image data to thereby track a tracking marker of the VR display device  2  of the associated trainee  9  and obtain a position and a posture of the trainee  9  in the real space. From the position and posture of the trainee  9  in the real space, the tracking controller  144  obtains a position and a posture of the self avatar based on the predetermined coordinate relationship. In addition, the tracking controller  144  performs image processing on the image data to thereby track the tracking markers of the controllers  3 B and obtain positions and postures of the hands of the trainee  9  in the real space. From the positions and the postures of the hands of the trainees  9  in the real space, the tracking controller  144  obtains positions and postures of the hands of the self avatar based on the predetermined coordinate relationship. That is, the tracking controllers  144  of the training terminals  1  of the hoist operator  93  and the descender  94  obtain positions and postures of the self avatars and positions and postures of the hands of the self avatars as position information. 
     The simulation progressor  146  generates a simulation image and controls progress of simulation of cooperative training in a manner similar to the training terminals  1  of the pilot  91  and the copilot  92 . It should be noted that, unlike the pilot  91  and the copilot  92  who remain seated on the pilot&#39;s seat and the copilot&#39;s, the hoist operator  93  and the descender  94  can move inside and outside the aircraft. Thus, the simulation progressor  146  freely moves the self avatar in the VR space. Based on the position information from the tracking controller  144 , the simulation progressor  146  changes a position or an angle of a frame of a simulation image to be displayed in accordance with the change of the position or orientation of the head of the hoist operator  93  or the descender  94 . In addition, in response to operation signals from the operation switches  35  of the controllers  3 B, the simulation progressor  146  performs processing in accordance with the operation signal to the self avatar in the VR space. The processing in accordance with the operation signal here is, for example, opening/closing of a door of the helicopter  8  or operation of the pendant-type operator. 
       FIG.  6    is a block diagram of the setting terminal  6  and peripheral equipment thereof. 
     The setting terminal  6  includes a display  61 , an inputter  62 , the communicator  63 , the memory  64 , and the processor  65 . 
     The display  61  is, for example, a liquid crystal display, an organic EL display, or a projector and a screen. 
     The inputter  62  accepts an input operation of an administrator (e.g., instructor) authorized to perform initial setting. The inputter  62  is, for example, a keyboard, a mouse, or a touch panel. 
     The communicator  63  is an interface that implements communication with, for example, the training terminal  1 . 
     The memory  64  includes a start program  641 , for example. The start program  641  is a program for causing a computer, that is, the processor  65 , to implement functions for causing the training terminals  1  that provides simulation images for performing simulation training in the common VR space to associated trainees to start simulation training. The start program  641  is read out and executed by the processor  65 . 
     The processor  65  reads and executes programs stored in the memory  64  to thereby collectively control parts of the setting terminal  6  and implement functions for performing initial setting concerning simulation. Specifically, the processor  65  includes a communication controller  651 , a setter  652 , and a monitor  654  as functional blocks. 
     The communication controller  651  performs a communication process with an external terminal or a device through the communicator  63 . The communication controller  651  executes data processing on data communication. 
     The setter  652  accepts an input of various types of setting information on initial setting necessary for generating a simulation image from a user, and sets the input setting information as initial setting. The setter  652  causes the display  61  to display a setting input screen stored in the memory  64 . The setter  652  causes the memory  64  to store setting information input to the setting input screen through the inputter  62  as initial setting. The setter  652  transmits setting information to the training terminals  1 . 
     The monitor  654  receives a simulation image from each of the training terminals  1 . That is, the monitor  654  receives a simulation image in a first-person viewpoint in accordance with each trainee  9 . The monitor  654  causes the display  61  to display the simulation image of one of the trainees  9  in a first-person viewpoint. Alternatively, the monitor  654  causes the display  61  to display the simulation images of all the trainees  9  in first-person viewpoints dividedly. In the case where all the simulation images in the first-person viewpoints are divided dividedly, the monitor  654  may cause the display  61  to display one of the simulation images in the first-person viewpoints in accordance with selection operation through the inputter  62 . 
     In starting training in the VR training system  100 , first, initial setting is performed in the setting terminal  6 . 
     Specifically, a setting input screen for performing initial setting is displayed in the display  61 , and an administrator such as an instructor inputs setting information to the setting input screen through the inputter  62 . 
     For example, the setter  652  receives, as setting information, information specifying the number of terminals to be connected (hereinafter referred to as “terminal number information”), information specifying IP addresses of terminals to be connected (hereinafter referred to as “terminal address information”), information specifying a training field where training simulation is performed (hereinafter referred to as “field information”), information specifying the direction of the boom of the helicopter (i.e., one of the left side and the right side of the helicopter in which the boom extends) (hereinafter referred to as “boom information”), and information specifying a position of a rescue requester in the training field (hereinafter referred to as “rescue requester information”). Based on the terminal number information and the terminal address information, a trainee to participate in training is specified. As the training field, fields such as a mountainous area are prepared. The field information includes a previously set initial position of the helicopter in the training field (i.e., initial position of an origin of a local coordinate system of the helicopter). The setter  652  sets these terminal number information, terminal address information, field information, boom information, and rescue requester information, as initial setting. The initial position of the helicopter may not be included in the field information, and may be input as an item of the setting information. 
     After completion of the initial setting, when the setting terminal  6  receives a connection request from the training terminals  1 , the setting terminal  6  transmits setting information to the training terminals  1  together with a connection completion response indicating completion of communication establishment. In response to this transmission, initial setting is performed in each of training terminals  1 . Thereafter, training starts in each of the training terminals  1 . In the setting terminal  6 , the monitor  654  causes the display  61  to display a simulation image in the VR space. Accordingly, an administrator such as an instructor can monitor cooperative training by the trainees  9  while watching the display  61 . 
       FIG.  7    is a flowchart of a training process of one of the training terminals  1  of the pilot  91  and the copilot  92  whose piloting function is effective. In this example, the piloting function of the training terminal  1  of the pilot  91  is effective. 
     First, in step Sa 1 , the processor  14  performs initial setting. Specifically, the pilot  91  inputs a connection request for connection to the setting terminal  6  through the inputter  11  of the training terminal  1  or the inputter  21  of the VR display device  2 . The simulation progressor  146  transmits the connection request to the setting terminal  6 . Then, the simulation progressor  146  receives a connection completion response from the setting terminal  6  so that communication with the setting terminal  6  is thereby established. At this time, the simulation progressor  146  also receives setting information of initial setting from the setting terminal  6 , The setter  142  sets the received setting information as initial setting of simulation. 
     Subsequently, in step Sa 2 , the simulation progressor  146  establishes communication with other terminals. Specifically, the trainee  9  performs an input requiring connection to other terminals through the inputter  11  of the training terminal  1  or the inputter  21  of the VR display device  2 . In response to this, the simulation progressor  146  transmits connection requests to the other training terminals  1  and the airframe calculating terminal  5 . Thereafter, the simulation progressor  146  receives connection completion responses from the other training terminals  1  and the airframe calculating terminal  5  to thereby establish communication with the other training terminals  1  and the airframe calculating terminal  5 . The simulation progressor  146  establishes communication with all the other training terminals  1  and the airframe calculating terminal  5 . 
     When communication with the other training terminals  1  is established, the simulation progressor  146  transmits initial position information on the self avatar (i.e., position coordinates (x, y, z) and rotation angles (Φ, θ, ψ)) to the other training terminals  1  in step Sa 3 . In addition, the simulation progressor  146  receives initial position information (i.e., position coordinates (x, y, z) and rotation angles (Φ, θ, ψ)) on other avatars from the other training terminals  1 . In a case where an avatar is present in the airframe  80 , the initial position information is position information not based on an absolute coordinate system in the VR space but based on a local coordinate system in the airframe  80  having an origin fixed at the airframe  80 . That is, the initial position is represented as a relative position to the airframe  80  in the VR space. 
     When the simulation progressor  146  receives the initial position information on the other avatars, the simulation progressor  146  causes the other avatars to be displayed in step Sa 4 . Specifically, the simulation progressor  146  reads the field definition data  132 , the avatar definition data  133 , and the object definition data  134  from the memory  13  based on the initial setting, and generates simulation images in which an object image and other avatar images are synthesized on a field image. At this time, the simulation progressor  146  places the other avatars based on the initial position information received in step Sa 3 . In a case where an avatar is generated in the airframe  80  in the VR space, the simulation progressor  146  generates an avatar relative to the local coordinate system of the airframe  80 . The airframe  80  is generated relative to the absolute coordinate system of the VR space. The simulation progressor  146  outputs, that is, provides, the generated simulation image to the VR display device  2 . In response to this, the VR display device  2  displays a simulation image. 
     In steps Sa 2  through Sa 4 , in the case where the simulation progressor  146  establishes communication with other training terminals  1 , the simulation progressor  146  acquires position information of other avatars from the other training terminals  1  and, based on the acquired position information, generates other avatars in the VR space. Steps Sa 1  through Sa 4  are processes regarding initial setting of training. 
     When the processes regarding initial setting are completed, processes in step Sa 5  and subsequent steps are performed. In step Sa 5 , the simulation progressor  146  transmits position information of the airframe  80  to the other training terminals  1 . In step Sa 6 , the simulation progressor  146  transmits position information of the self avatar to the other training terminals  1 . In addition, the simulation progressor  146  receives position information of other avatars from the other training terminals  1 . In step Sa 7 , the simulation progressor  146  updates positions and postures of the other avatars. 
     In updating the positions and postures of the other avatars, since the simulation progressor  146  acquires position information of the other avatars from the other training terminals  1 , a calculation load of the processor  14  can be reduced. Specifically, since the tracking system  4  tracks the VR display devices  2  and the controllers  3 B of the trainees  9 , the tracking controller  144  can also calculate positions and postures of the other avatars based on image data from the tracking system  4 . The positions and postures of the other avatars are, however, calculated by the other training terminals  1  associated with the other avatars. The simulation progressor  146  acquires position information of the other avatars calculated by the other training terminals  1 , and based on this position information, updates the positions and postures of the other avatars. In the manner described above, since the processor  14  does not need to calculate positions and postures of the other avatars based on detection results (i.e., image data) of the tracking system  4 , a calculation load can be reduced. 
     Subsequently, in step Sa 8 , the simulation progressor  146  determines whether simulation is being executed or not, that is, whether simulation continues or not. If simulation is finished, the processor  14  ends the process. On the other hand, if simulation continues, the simulation progressor  146  determines whether a predetermined time has elapsed or not, in step Sa 9 . The predetermined time corresponds to a period of updating positions and postures of the airframe  80  and the other avatars, and is set beforehand. The predetermined time, that is, the update period, is common to the training terminals  1 . The predetermined time may be different among the training terminals  1 . If the predetermined time has not elapsed, the simulation progressor  146  repeats steps Sa 8  and Sa 9 . During this repetition, the simulation progressor  146  performs calculation processes regarding progress of simulation. For example, the simulation progressor  146  acquires movement amount information of the airframe updated by the airframe calculating terminal  5  in response to the operation inputs through the piloting devices  3 A, and based on the movement amount information, updates the position and posture of the airframe  80  in the VR space. The simulation progressor  146  updates the position and posture of the self avatar based on position information from the tracking controller  144 . 
     If the predetermined time has elapsed, the simulation progressor  146  returns to step Sa 5 . In this case, there is a possibility that the position of the airframe  80  has been updated from the previous step Sa 5 . That is, the simulation progressor  146  transmits latest position information of the airframe  80  to the other training terminals  1 . Similarly, in step Sa 6 , the simulation progressor  146  transmits latest position information of the self avatar to other training terminals  1 . In addition, the simulation progressor  146  receives latest position information of other avatars from the other training terminals  1 . In step Sa 7 , the simulation progressor  146  updates positions and postures of the other avatars. Subsequently, the simulation progressor  146  performs steps Sa 8  and Sa 9 . 
     In the manner described above, the simulation progressor  146  repeats steps Sa 5  through Sa 9  to thereby periodically acquire position information of the other avatars from the other training terminals  1  and update positions and postures of the other avatars in the VR space. At this time, the simulation progressor  146  also updates the positions and postures of the airframe  80  and the self avatar when necessary to periodically transmit latest position information of the airframe  80  and the self avatar to the other training terminals  1 . That is, while updating the positions and postures of the airframe  80  and the self avatar, the simulation progressor  146  periodically transmits latest position information of the airframe  80  and the self avatar to the other training terminals  1  and receives latest position information of the other avatars to thereby periodically update the positions and postures of the other avatars. 
       FIG.  8    is a flowchart of a training process of the training terminals  1  of the hoist operator  93  and the descender  94 . The following training process is performed independently in each of the training terminals  1  of the hoist operator  93  and the descender  94 . One of the training terminals  1  of the pilot  91  and the copilot  92  whose piloting function is not effective (the training terminal  1  of the copilot  92  in this example) performs a process similar to the training terminals  1  of the hoist operator  93  and the descender  94 .  FIGS.  9  through  11    show examples of VR space generated by the training terminal  1  of the hoist operator  93 .  FIGS.  9  through  11    illustrate the VR space in a third-person viewpoint for convenience of description, and is different from an image in a first-person viewpoint displayed in the VR display device  2 . 
     First, in step Sb 1 , the processor  14  sets initial setting. Specifically, the trainee  9  (the hoist operator  93  or the descender  94 ) inputs a connection request for connection to the setting terminal  6  through the inputter  11  of the training terminal  1  or the inputter  21  of the VR display device  2 . The simulation progressor  146  transmits the connection request to the setting terminal  6 . Then, the simulation progressor  146  receives a connection completion response from the setting terminal  6  so that communication with the setting terminal  6  is thereby established. At this time, the simulation progressor  146  also receives setting information of initial setting from the setting terminal  6 . The setter  142  sets the received setting information as initial setting of simulation. 
     Next, in step Sb 2 , the simulation progressor  146  displays the self avatar. Specifically, the simulation progressor  146  reads the field definition data  132 , the avatar definition data  133 , and the object definition data  134  from the memory  13  based on the initial setting, and generates simulation images in which an object image and the self avatar images are synthesized on a field image. The simulation progressor  146  outputs, that is, provides, the generated simulation image to the VR display device  2 . In response to this, the VR display device  2  displays a simulation image. At this time, in a case where the self avatar of the trainee is present in the airframe  80 , initial position information included in the avatar definition data  133  of the self avatar is position information not based on an absolute coordinate system in the VR space but based on a local coordinate system in the airframe  80  having an origin fixed at the airframe  80 . That is, the initial position is represented as a relative position to the airframe  80  in the VR space. 
     It should be noted that in the avatars of the pilot  91  and the copilot  92 , only the heads are movable and the bodies other than the heads are fixed in the VR space, and thus, one of the training terminals  1  of the pilot  91  and the copilot  92  whose piloting function is not effective does not generate the self avatar image in the simulation image. That is, since the training terminal  1  changes a position or an angle of a frame of a simulation image to be displayed and transmits position information (specifically, position information of the head) of the self avatar is transmitted to the other training terminals  1 , the training terminal  1  generates the self avatar in the VR space but does not generate the self avatar as a simulation image. Note that the training terminal  1  may generate an image of, for example, arms or legs of the self avatar as a fixed object. 
       FIG.  9    is an example of VR space generated by the training terminal  1  of the hoist operator  93  when the self avatar is displayed in step Sb 2 . In  FIG.  9   , the helicopter  8  is generated together with a mountainous object  71  in VR space  7 . In step Sb 2 , the self avatar  93 A of the hoist operator  93  is generated in the airframe  80  of the helicopter  8 . 
     Subsequently, in step Sb 3 , the simulation progressor  146  establishes communication with other terminals. Specifically, the trainee  9  performs an input requiring connection to other terminals through the inputter  11  of the training terminal  1  or the inputter  21  of the VR display device  2 . In response to this, the simulation progressor  146  transmits a connection request to the other training terminals  1 . Then, the simulation progressor  146  receives connection completion responses from the other training terminals  1  so that communication with the other training terminals  1  is thereby established. The simulation progressor  146  establishes communication with all the other training terminals  1 . 
     When communication with the other training terminals  1  is established, the simulation progressor  146  transmits initial position information of the self avatar to the other training terminals  1  in step Sb 4 . In addition, the simulation progressor  146  receives initial position information of other avatars from the other training terminals  1 . 
     When the simulation progressor  146  receives the initial position information on the other avatars, the simulation progressor  146  causes the other avatars to be displayed in step Sb 5 . Specifically, the simulation progressor  146  reads the avatar definition data  133  associated with the other avatars from the memory  13 , and syntheses the other avatars in the VR space generated in step Sb 2 . At this time, the simulation progressor  146  places the other avatars based on the initial position information received in step Sb 4 . In a case where an avatar is generated in the airframe  80  in the VR space, the simulation progressor  146  generates an avatar based on the local coordinate system of the airframe  80 . The airframe  80  is generated based on the absolute coordinate system of the VR space. The simulation progressor  146  outputs, that is, provides, the generated simulation image to the VR display device  2 . In response to this, the VR display device  2  displays a simulation image. 
     In steps Sa 3  through Sa 5 , when the simulation progressor  146  establishes communication with other training terminals  1 , the simulation progressor  146  acquires position information of other avatars from the other training terminals  1  and, based on the acquired position information, generates other avatars in the VR space. 
       FIG.  10    is an example of VR space generated by the training terminal  1  of the hoist operator  93  when other avatars are displayed in step Sb 5 . In  FIG.  10   , the helicopter  8  is generated together with the mountainous object  71  in VR space  7 . In step Sb 5 , in addition to the avatar  93 A of the hoist operator  93  that is the self avatar, the avatar  91 A of the pilot  91 , the avatar  92 A of the copilot  92 , and the avatar  94 A of the descender  94  as other avatars are generated in the airframe  80  of the helicopter  8 . Steps Sb 1  through Sb 5  are processes regarding initial setting of training. 
     When the processes regarding initial setting are completed, the training is started and processes in step Sb 6  and subsequent steps are performed. In step Sb 6 , the simulation progressor  146  receives position information of the airframe  80  from the airframe terminal  50  (specifically the training terminal  1  of the pilot  91 ). In step Sb 7 , the simulation progressor  146  transmits position information of the self avatar to other training terminals  1 . In addition, the simulation progressor  146  receives position information of other avatars from the other training terminals  1 . As described in the process of the training terminal  1  of the pilot  91 , position information of the airframe  80  and position information of the avatar of the pilot  91  are periodically transmitted. Since the other training terminals  1  also periodically repeat step Sb 7 , position information of the other avatars is periodically transmitted from the other training terminals  1 . 
     In step Sb 8 , the simulation progressor  146  updates the positions and postures of the self avatar, the other avatars, and the airframe  80 . At this time, if the self avatar and the other avatars are present in the airframe  80 , position information of the self avatar and the other avatars are position information based on the local coordinate system of the airframe  80 . The simulation progressor  146  updates the position and posture of the airframe  80  based on the position information of the airframe  80 , and updates the positions and postures of the self avatar and the other avatars relative to the updated airframe  80 . 
     In updating the positions and postures of the self avatar, the other avatars, and the airframe  80 , since the simulation progressor  146  acquires position information of the other avatars and the airframe  80  from the other training terminals  1 , a calculation load of the processor  14  can be reduced as described above. 
     Subsequently, in step Sb 9 , the simulation progressor  146  determines whether simulation is being executed or not, that is, whether simulation continues or not. If simulation is finished, the processor  14  ends the process. On the other hand, if simulation continues, the simulation progressor  146  determines whether a predetermined time has elapsed or not, in step Sb 10 . The predetermined time corresponds to a period of updating the positions and postures of the self avatar, the other avatar, and the airframe  80 , and is set beforehand. The predetermined time, that is, the update period, is common to the training terminals  1 . The predetermined time may be different among the training terminals  1 . If the predetermined time has not elapsed, the simulation progressor  146  repeats steps Sb 9  and Sb 10 . During this repetition, the simulation progressor  146  performs calculation processes regarding progress of simulation. For example, the simulation progressor  146  calculates the position and posture of the self avatar based on position information from the tracking controller  144 . In this example, the positions and postures of the self avatar, the other avatars, and the airframe  80  are updated in the same periods, but the update periods of the self avatar, the other avatars, and the airframe  80  may be different from one another. 
     If the predetermined time has elapsed, the simulation progressor  146  returns to step Sb 6 . In this case, there is a possibility that the position of the airframe  80  has been updated from the previous step Sb 6 . That is, the simulation progressor  146  receives latest position information of the airframe  80  from the training terminal  1  of the pilot  91 . Similarly, in step Sb 7 , the simulation progressor  146  transmits latest position information of the self avatar to other training terminals  1 . In addition, the simulation progressor  146  receives latest position information of other avatars from other training terminals  1 . In step Sb 8 , the simulation progressor  146  updates the positions and postures of the other avatars. In addition, in a case where the self avatar is disposed in the airframe  80  and the position and posture of the airframe  80  have been updated, the simulation progressor  146  updates the position and posture of the self avatar in accordance with the updated position and posture of the airframe  80 . Subsequently, the simulation progressor  146  performs steps Sb 9  and Sb 10 . 
     In this manner, the simulation progressor  146  repeats steps Sb 6  through Sb 10  to thereby periodically acquire position information of the other avatars from the other training terminals  1  and update the positions and postures of the other avatars in the VR space. The simulation progressor  146  periodically acquires position information of the airframe  80  from the airframe terminal  50  and updates the position and posture of the airframe  80  in the VR space. The simulation progressor  146  also updates the position of the self avatar when necessary and periodically transmits the latest position information of the self avatar to the other training terminals  1 . That is, while updating the position and posture of the self avatar, the simulation progressor  146  periodically transmits the latest position information of the self avatar to the other training terminals  1  and receives latest position information of the other avatars and the airframe  80  to thereby periodically update the positions and postures of the airframe  80 , the self avatar, and the other avatars. 
       FIG.  11    is an example of VR space generated by the training terminal  1  of the hoist operator  93  when the positions and postures of the self avatar, the other avatars, and the airframe  80  are updated. In  FIG.  11   , the airframe  80  is moved as compared to  FIG.  10   , and a positional relationship between the helicopter  8  and the mountainous object  71  in the VR space  7  are changed. Accordingly, the avatars  91 A through  94 A are moved in the VR space  7 . In addition, the avatars  93 A and  94 A are also moved in the airframe  80 . 
     In this training process, since the simulation progressor  146  acquires position information of the other avatars from the other training terminals  1 , the tracking controller  144  does not need to calculate position information of the other avatars. Thus, the processor  14  can update the positions and postures of the other avatars with fewer calculation processes. In addition, since the simulation progressor  146  acquires position information of the airframe  80  from the airframe terminal  50  and position information of the avatar in the airframe  80  is based on the local coordinate system of the airframe, it is unnecessary to calculate the amount of movement of the avatar in the VR space due to movement of the airframe  80 . The simulation progressor  146  updates the position and posture of the airframe  80  in the absolute coordinate system of the VR space based on position information of the airframe  80 , and updates relative positions and postures of the avatars relative to the updated position of the airframe  80 . In this manner, the processor  14  can update the positions and postures of the avatars with fewer calculation processes. 
     Next, an example of simulation training in the VR training system  100  will be described. This simulation training is cooperative training performed by four trainees  9  (i.e., the pilot  91 , the copilot  92 , the hoist operator  93 , and the descender  94 ), and the helicopter  8  flies to a point where a rescue requester  88  is present to rescue the rescue requester  88 . The piloting function of the training terminal  1  of the pilot  91  is set effective.  FIG.  12    is a flowchart showing a flow of training processes in simulation training. This simulation training starts after the process regarding initial setting described above is completed. Various operations of the piloting devices  3 A and the controllers  3 B are allocated with various processes depending on training situations. Each training terminal  1  performs a process associated with an operation of the piloting device  3 A and the controllers  3 B depending on situations in a simulation image. 
     In the simulation training, first, flight training is performed in step Sc 1 . The flight training is training of flying the helicopter  8  from a departure point to a point where the rescue requester  88  is present (i.e., rescue point). The pilot  91  flies the helicopter  8  in the simulation image by operating the piloting device  3 A. The training terminal  1  of the pilot  91  changes a position and a posture of the airframe  80  in VR space based on a calculation result of the airframe calculating terminal  5 . 
     The other training terminals  1  acquires a position and a posture of the airframe  80  calculated by the training terminal  1  of the pilot  91 , and generates a simulation image in which the position and the posture of the airframe  80  are updated. The copilot  92 , for example, performs safety check during flight while watching the simulation image. For example,  FIG.  10    is an example of a simulation image of the hoist operator  93  in flight training. This simulation image is an image in a case where the hoist operator  93  faces the pilot&#39;s seat in the airframe  80 . This simulation image shows an avatar  91 A of the pilot  91  and an avatar  92 A of the copilot  92  seated on the pilot&#39;s seat and the copilot&#39;s seat, respectively. 
     When the helicopter  8  arrives at the rescue point, flight training is completed. 
     Next, hovering training in step Sc 2  is performed. The hovering training is training for continuously suspending the helicopter  8  at a predetermined position in the air. In this hovering training, a pilot action by the pilot  91  and a safety check action by, for example, the copilot  92  are performed. 
     When hovering flight is performed with stability, hovering training is completed, 
     Next, descent training in step Sc 3  is performed.  FIG.  14    is an example of a simulation image of the hoist operator  93  or the descender  94  in descent training.  FIG.  15    is an example of a simulation image of the descender  94  in descent training.  FIG.  16    is a view illustrating an example of a layout situation in VR space in descent training.  FIG.  17    is an example of a simulation image of the copilot  92  in descent training.  FIG.  18    is an example of a simulation image of the hoist operator  93  in descent training 
     The descent training is training in which the hoist operator  93  allows the descender  94  to descend from the airframe  80  by operating the hoisting machine  84 . That is, after the avatar  94 A of the descender  94  is coupled to the hoist cable  82 , the hoist operator  93  operates the hoisting machine  84  to allow the avatar  94 A of the descender  94  to descend. 
     For example, in the descent training, the hoist operator  93  and the descender  94  move the self avatars to the vicinity of the door of the airframe  80 . This movement of the self avatars is implemented by operation of the controller  3 B by the hoist operator  93  or the descender  94 . For example, when the hoist operator  93  or the descender  94  presses the operation switch  35  halfway, a pointer  70  is thereby displayed on a floor  85  of the airframe  80  as illustrated in  FIG.  14   . The hoist operator  93  or the descender  94  adjusts the direction of the controller  3 B with the operation switch  35  pressed halfway, thereby adjusting the position of the pointer  70 . When the hoist operator  93  or the descender  94  fully presses the operation switch  35 , the self avatars can be moved to the position of the pointer  70 . In this manner, even if the hoist operator  93  or the descender  94  does not actually move in real space, self avatars thereof can be moved in VR space. The movement of the self avatars may be implemented by actual movement of the hoist operator  93  or the descender  94  in real space. 
     The display of the pointer  70  on the floor  85  here substantially means selection of a point of an object corresponding to destination of the avatar. Selection of an object on a part of the object is performed by overlaying the pointer  70  on the object on a part of the object in display. 
     Next, the hoist operator  93  or the descender  94  selects the door of the airframe  80  by the pointer  70  by operating the controller  3 B. In this state, when the hoist operator  93  or the descender  94  fully presses the operation switch  35 , the door is made open. 
     As illustrated in  FIG.  15   , the descender  94  selects a front end of the hoist cable  82  or a vicinity of a carabiner  86  by the pointer  70  In this state, when the descender  94  fully presses the operation switch  35 , the carabiner  86  is thereby coupled to a band  87  of the avatar  94 A of the descender  94  (see  FIG.  16   ). The avatar  94 A of the descender  94  is previously equipped with the band  87  different from the rescue band  83 . Accordingly, as illustrated in  FIG.  13   , the avatar  94 A of the descender  94  is coupled to the hoist cable  82 , and the avatar  94 A of the descender  94  is hung by the hoist cable  82 . 
     At this time, as illustrated in  FIG.  17   , the copilot  92  checks situations of the avatar  93 A of the hoist operator  93  and the avatar  94 A of the descender  94 , and gives advice on hovering flight to the pilot  91  when necessary. 
     On the other hand, the hoist operator  93  selects the pendant-type operator by the pointer  70  and fully presses the operation switch  35  in this state, thereby causing the avatar  93 A of the hoist operator  93  to hold the pendant-type operator. As illustrated in  FIG.  18   , the hoist operator  93  moves in the real space in such a manner that the avatar  93 A of the hoist operator  93  leans out of the airframe  80 . In this manner, the hoist operator  93  can visually recognize the avatar  94 A of the descender  94  hung by the hoist cable  82 . The hoist operator  93  operates the operation switch  35  with the avatar  93 A of the hoist operator  93  holding the pendant-type operator so that the hoist cable  82  is thereby drawn and the avatar  94 A of the descender  94  gradually descends. 
     At this time, the descender  94  performs hand signals (i.e., moves the controllers  3 B) in the real space in accordance with a distance to the ground surface in the VR space. Accordingly, the avatar  94 A of the descender  94  performs similar hand signals, and notifies the hoist operator  93  of the distance between the avatar  94 A of the descender  94  and the ground surface. The hoist operator  93  adjusts the amount of drawing of the hoist cable  82  in accordance with the hand signals of the avatar  94 A of the descender  94 . 
     When the avatar  94 A of the descender  94  approaches the ground surface, the descender  94  selects a target landing point by the pointer  70 . In this state, the descender  94  fully presses the operation switch  35  so that the avatar  94 A of the descender  94  is thereby landed on the target landing point. At this time, an action in which the avatar  94 A of the descender  94  releases coupling to the hoist cable  82  is omitted, and the avatar  94 A of the descender  94  is disconnected from the hoist cable  82 . In this manner, descent training is completed. 
     Subsequently, rescue training in step Sc 4  is performed.  FIG.  19    is an example of a simulation image of the descender  94  in rescue training.  FIG.  20    is an example of a simulation image of the descender  94  in rescue training. 
     The descender  94  moves the avatar  94 A of the descender  94  to the place of the rescue requester  88 . In a manner similar to the movement in the airframe  80 , this movement is implemented by selection of destination by the pointer  70  and full pressing of the operation switch  35 . 
     In a state where the avatar  94 A of the descender  94  moves to the rescue requester  88 , the descender  94  presses the operation switch  35  halfway, and if the rescue requester  88  is within a rescuable range, the contour of the rescue requester  88  is colored in display, as illustrated in  FIG.  19   . The descender  94  adjusts the directions of the controllers  3 B, and touches the rescue requester  88  with the hands of the avatar  94 A of the descender  94 . In this state, when the descender  94  fully presses the operation switch  35 , the rescue requester  88  is tied to the rescue band  83  as illustrated in  FIG.  20   . That is, an action in which the avatar  94 A of the descender  94  moves the rescue requester  88  to the position of the rescue band  83  and an action in which the avatar  94 A of the descender  94  ties the rescue band  83  to the rescue requester  88  are omitted. 
     Thereafter, the descender  94  moves the avatar  94 A of the descender  94  to the place of the hoist cable  82 . This movement has been described above. 
     In the state where the avatar  94 A of the descender  94  has moved to the hoist cable  82 , the descender  94  selects the hoist cable  82  by the pointer  70  and fully presses the operation switch  35  so that the avatar  94 A of the descender  94  is thereby coupled to the hoist cable  82 . In this manner, rescue training is completed. 
     Thereafter, pull-up training in step Sc 5  is performed.  FIG.  21    is an example of a simulation image of the descender  94  in pull-up training. 
     The descender  94  performs hand signals to send a signal of pull-up to the hoist operator  93 . 
     The hoist operator  93  checks the hand signals of the avatar  94 A of the descender  94 , and operates the pendant-type operator to start pull-up of the avatar  94 A of the descender  94  and the rescue requester  88 . The hoist operator  93  adjusts the pull-up amount of the hoist cable  82  while visually recognizing the avatar  94 A of the descender  94 . 
     The descender  94  may send hand signals to the avatar  93 A of the hoist operator  93  depending on the pull-up situation. For example, when the hoist cable  82  swings greatly, the descender  94  may send a signal of temporarily stopping pull-up to the avatar  93 A of the hoist operator  93 . When swing of the hoist cable  82  is stopped, the descender  94  may send a signal of restarting pull-up to the avatar  93 A of the hoist operator  93 . In this case, the hoist operator  93  temporarily stops pull-up and restarts pull-up, for example, in accordance with the hand signals of the avatar  94 A of the descender  94 . 
     As illustrated in  FIG.  21   , when the avatar  94 A of the descender  94  is pulled up to the vicinity of the airframe  80 , the descender  94  selects a part of the inside of the airframe  80  with the pointer  70  and fully presses the operation switch  35 . Accordingly, the avatar  94 A of the descender  94  gets in the airframe  80 . Thereafter, the hoist operator  93  selects the rescue band  83  by the pointer  70  and fully presses the operation switch  35 . Accordingly, the rescue requester  88  is pulled up into the airframe  80 . That is, an action in which the avatar  94 A of the descender  94  gets in the airframe  80  and an action in which the avatar  93 A of the hoist operator  93 , for example, pulls the rescue requester  88  into the airframe  80  are omitted. In this manner, pull-up training is completed. 
     Thereafter, flight training in step Sc 6  is performed. The flight training in step Sc 6  is similar to the flight training in step Sc 1 . This flight training is training of flying the helicopter  8  to the original departure point. The pilot  91  flies the helicopter  8  by operating the piloting devices  3 A. The copilot  92 , for example, performs safety check during flight. When the helicopter  8  arrives at the original departure point, flight training is finished, and a series of simulation training (cooperative training) is finished. 
     This simulation training is merely an example, and the contents of the simulation training are not limited to this example. 
     As described above, the aircraft VR training system  100  includes: the training terminals  1  that generates simulation images for performing simulation training in common VR space and provides the simulation images to trainees  9  individually associated with the training terminals  1 ; and the tracking sensor  41  that detects motion of the trainees  9  in real space. Each of the training terminals  1  calculates a position and a posture of a self avatar that is an avatar of the trainee associated with the training terminal in the VR space, acquires position information on a position and a posture of another avatar associated with another training terminal  1  of the training terminals  1  in the VR space from the another training terminals  1 , and generates the another avatar in the VR space based on the acquired position information of the another avatar. 
     An aircraft VR training method is an aircraft VR training method for enabling trainees individually associated with training terminals  1  to perform simulation training by using simulation images in common VR space generated by the training terminals  1 , and the aircraft VR training method includes: causing each of the training terminals  1  to calculate a position and a posture of a self avatar that is an avatar of one of the trainees associated with the training terminal in the VR space based on a detection result of a tracking sensor  41  that detects motion of the trainees  9  in real space; and causing each of the training terminals  1  to acquire position information on a position and a posture of another avatar that is an avatar of another one of the trainees associated with another training terminal  1  of the training terminals  1 , and to generate the another avatar in the VR space based on the acquired position information of the another avatar. 
     The simulation program  131  is an aircraft VR training program for causing processors  14  (computers) of the training terminals  1  to execute the function of generating simulation images for performing simulation training in common VR space and of providing the simulation images to trainees  9  individually associated with the training terminals  1 , and the simulation program  131  causes the processors  14  to execute the functions of: calculating a position and a posture of a self avatar that is an avatar of an associated one of the trainees  9  in the VR space based on a detection result of the tracking sensor  41  that detects motion of the trainees  9  in real space; and acquiring position information on a position and a posture of another avatar that is an avatar of one of the trainees  9  associated with another training terminal  1  of the training terminals  1  in the VR space from the another training terminal  1 , and generating the another avatar in the VR space based on the acquired position information of the another avatar. 
     With these configurations, each of the training terminals  1  calculates position information of the self avatar of the associated trainee  9 , that is, a position and a posture in the VR space, based on detection results of the tracking sensor  41 . On the other hand, for the other avatars of the trainees  9  associated with the other training terminals  1 , each of the training terminals  1  acquires trainee position information of the other avatars from the other training terminals  1  associated with the other avatars. The other training terminals  1  associated with the other avatars calculate positions and postures of the other avatars in the VR space based on detection results of the tracking sensor  41 , and thus, hold position information of the other avatars. Thus, each of the training terminals  1  does not need to calculate the positions and postures of the other avatars based on the detection results of the tracking sensor  41 . 
     In this manner, calculation processes of the positions and postures of the avatars in the VR space based on the detection results of the tracking sensor  41  are distributed to the training terminals  1  associated with the avatars. Position information of the avatars as calculation results is shared by other training terminals  1 . Accordingly, a calculation load of each training terminals  1  in generating the avatar can be reduced. 
     After establishing communication with other training terminals  1 , each of the training terminals  1  acquires position information of other avatars from the other training terminals  1 , and generates the other avatars in the VR space based on the acquired position information of the other avatars. 
     With this configuration, each of the training terminals  1  can acquire position information of the other avatars from the other training terminals  1  by establishing communication with the other training terminals  1 , and generate the other avatars at appropriate positions in the VR space. 
     In addition, the VR training system  100  further includes: the piloting devices  3 A that is operated by one of the trainees who pilots an aircraft; and the airframe terminal  50  that calculates a position and a posture of the airframe  80  of the aircraft based on operation inputs through the piloting devices  3 A. The training terminals  1  acquire position information on a position and a posture of the airframe  80  in the VR space from the from the airframe terminal  50 , and generates the airframe  80  in the VR space based on the acquired position information of the airframe  80 . 
     With this configuration, the aircraft airframe  80  is generated in the VR space, and the airframe  80  flies in response to operation inputs from the piloting devices  3 A. At this time, each of the training terminals  1  does not calculate the position and posture of the airframe  80  in the VR space, but the airframe terminal  50  calculates the position and posture of the airframe  80  in the VR space. The training terminals  1  acquire position information of the airframe  80  from the airframe terminal  50 , and generate the airframe  80  in the VR space based on the acquired position information. Accordingly, the training terminals  1  do not need to perform the same calculation again, and thus, a calculation load can be reduced in the entire terminals. 
     Specifically, the airframe terminal  50  includes the airframe calculating terminal  5  that calculates the amount of movement and the amount of change of posture of the airframe based on operation input through the piloting devices  3 A, and the training terminal  1  that is one of the training terminals  1  and computes a position and a posture of the airframe  80  in the VR space based on movement amount information on the amount of movement and the amount of change of posture of the airframe  80  from the airframe calculating terminal  5 . 
     With this configuration, one training terminal  1  has a part of the functions of the airframe terminal  50 . Specifically, the airframe calculating terminal  5  and one training terminal  1  calculates the position and posture of the airframe  80  in the VR space in cooperation in response to operation inputs of the piloting devices  3 A. In this manner, the airframe terminal  50  is formed by terminals so that a calculation load of the terminals can be reduced. 
     The airframe terminal  50  updates position information of the airframe  80  in response to operation inputs through the piloting devices  3 A. The training terminals  1  periodically acquire position information of the airframe  80  from the airframe terminal  50  and updates the position and posture of the airframe  80  in the VR space. 
     With this configuration, in response to the operation inputs from the piloting devices  3 A, the position and posture of the airframe  80  in the VR space are updated when necessary. 
     In addition, in the case of generating avatars in the airframe  80  in the VR space, the training terminals  1  generate the avatars based on the local coordinate system having an origin fixed at the airframe  80  based on position information of the airframe  80  acquired from the airframe terminal  50 . 
     With this configuration, in calculating the positions and postures of avatars in the VR space by the training terminals  1 , influences of change of the position and posture of the airframe  80  do not need to be taken into consideration. Since the training terminals can acquire position information of the airframe  80  from the airframe terminal  50 , the training terminals can appropriately place the avatars in the airframe  80  in the VR space by generating avatars based on the local coordinate system of the airframe  80 . 
     Each of the training terminals  1  periodically acquires position information of other avatars from other training terminals  1  and updates the positions and postures of the avatars in the VR space. 
     With this configuration, each of the training terminals  1  also acquire position information of the avatars from the other training terminals  1  in updating the positions and postures of the other avatars in the VR space, and thus, does not need to calculate the positions and postures of the other avatars in the VR space based on detection results of the tracking sensor  41 . 
     Other Embodiments 
     In the foregoing section, the embodiment has been described as an example of the technique disclosed in the present application. The technique disclosed here, however, is not limited to this embodiment, and is applicable to other embodiments obtained by changes, replacements, additions, and/or omissions as necessary. Components described in the embodiment described above may be combined as a new exemplary embodiment. Components provided in the accompanying drawings and the detailed description can include components unnecessary for solving problems as well as components necessary for solving problems in order to exemplify the technique. Therefore, it should not be concluded that such unnecessary components are necessary only because these unnecessary components are included in the accompanying drawings or the detailed description. 
     For example, the VR training to which the VR training system  100  is applied is not limited to VR training using the helicopter. The VR training system  100  is also applicable to VR training using an aircraft other than the helicopter. 
     In a case where calculation capacity of the training terminal  1  of the pilot  91  and the training terminal  1  of the copilot  92  have margins, for example, the airframe calculating terminal  5  may be omitted, and each of the training terminal  1  of the pilot  91  and the training terminal  1  of the copilot  92  may calculate the amount of movement and the amount of change of posture of the airframe in the VR space. In this case, each of the training terminal  1  of the pilot  91  and the training terminal  1  of the copilot  92  is connected to its associated piloting device  3 A. In this case, one training terminal  1  of the training terminals (specifically, one of the training terminals  1  of the pilot  91  and the copilot  92  whose piloting function is effective) functions as the airframe terminal for calculating a position and a posture of the airframe  80  of the aircraft in the VR space based on an operation input through the piloting device  3 A. 
     Alternatively, the airframe calculating terminal  5  does not only calculate the amount of movement and the amount of change of posture of the airframe based on an operation input through the piloting devices  3 A, but also may calculate a position and a posture of the airframe  80  in the VR space based on movement amount information. In this case, the airframe calculating terminal  5  is a terminal other than the training terminals  1  and serves as an airframe terminal that calculates a position and a posture of the airframe  80  of the aircraft in the VR space based on the operation input through the piloting devices  3 A. 
     Alternatively, each of the training terminals  1  may acquire movement amount information from the airframe calculating terminal  5 , and calculate a position and a posture of the airframe  80  in VR space based on the movement amount information. 
     The training terminals  1  of the pilot  91  and the copilot  92  generate avatars only whose heads are movable in order to reduce a calculation load, but the present disclosure is not limited to this. The training terminals  1  of the pilot  91  and the copilot  92  may generate avatars such that operation of the whole bodies of the trainees  9  are reflected, in a manner similar to the training terminals  1  of the hoist operator  93  and the descender  94 . 
     The setting terminal  6  may not be a terminal different from the training terminals  1 . The training terminals  1  may function as the setting terminal  6 . That is, any one of the training terminals  1  may function as the setting terminal  6 . For example, an instructor may serve as the copilot  92  and participate in training. In this case, the training terminal  1  of the copilot  92  has the function similar to that of the setting terminal  6 . The instructor inputs setting information of initial setting to the training terminal  1  of the copilot  92 , and the training terminal  1  of the copilot  92  transmits the setting information to another training terminal  1 . The instructor monitors training of the other trainees  9  while participating in training as the copilot  92 . 
     The setting terminal  6  may not have the function of monitoring training. 
     The trainees  9  are not limited to the pilot  91 , the copilot  92 , the hoist operator  93 , and the descender  94 . The trainees  9  may be two or three of these trainees. Alternatively, the trainees  9  may be persons other than the four described above. That is, any person who can perform cooperative training by using the VR training system  100  can be a trainee  9 . For example, the trainees  9  may include a land staff (person who guides a helicopter on the ground surface), an air traffic controller, or a rescue requester. 
     As setting information of initial setting, initial positions of the trainees  9  in the VR space may be set. For example, if the trainee  9  is a land staff, a position of the trainee  9  on the ground surface in the VR space can be set. 
     In the flowcharts of  FIGS.  7  and  8   , steps may be omitted, the order of steps may be changed, or steps may be processed in parallel, or another step may be added, to the extent practicable. 
     In the flowchart of  FIG.  7   , in step Sa 2 , the training terminal  1  establishes communication with other training terminals  1 , but the timing when communication with the other training terminals  1  is established is not limited to this example. For example, in step Sa 1 , in performing initial setting, communication with other training terminals  1  may be established. Similarly, in the flowchart of  FIG.  8   , in step Sb 3 , the training terminal  1  establishes communication with other training terminals  1 , but the timing when communication with the other training terminals  1  is established is not limited to this example. For example, in step Sb 1 , in performing initial setting, communication with other training terminals  1  may be established. 
     Although the training terminal  1  displays the self avatar in step Sb 2 , the timing of displaying the self avatar is not limited to this example. For example, in step Sb 5 , the training terminal  1  may display the self avatar at the timing of displaying other avatars. 
     An image displayed by the VR display device  2  is not limited to a simulation image in a first-person viewpoint. For example, the VR display device  2  may display a simulation image in a third-person viewpoint. 
     The tracking system  4  can employ any technique as long as the tracking system  4  can track movement of the trainees  9 . For example, the tracking system  4  may be an inside-out system. 
     The piloting devices  3 A and the controllers  3 B as operation devices can be appropriately changed depending on trainees and training contents. 
     The contents of operation that can be performed by the piloting devices  3 A and the controllers  3 B may be appropriately changed depending on trainees and training contents. For example, icons, for example, displayed by the VR display device  2  may be operated through the piloting devices  3 A or the controllers  3 B so that the piloting devices  3 A or the controllers  3 B function in a manner similar to the inputter  11 . 
     The functions of the configuration disclosed in this embodiment may be executed by using an electric circuit or a processing circuit. The electric circuit or the processing circuit may be a main processor, a dedicated processor, an integrated circuit, an ASIC, a conventional electric circuit, a controller, or any combination thereof, configured or programmed to execute the disclosed functions. The processor or the controller is, for example, a processing circuit including a transistor and other circuits. In this disclosure, a circuit, a unit, a controller, or a means are hardware or are programmed in order to execute the functions described here. The hardware here is a hardware disclosed in this embodiment or a known hardware, configured or programmed to execute the functions disclosed in this embodiment. In a case where the hardware is a processor or a controller, a circuit, a means, or a unit is a combination of hardware and software, and software is used for constituting the hardware and/or the processor.