Patent Publication Number: US-2021178933-A1

Title: Vehicle Seat and Passenger Selection System

Description:
TECHNICAL FIELD 
     The present invention relates to a vehicle seat, and a passenger selection system for use in carpooling or any other car sharing system. 
     BACKGROUND ART 
     A vehicle seat disclosed in JP2010-253182A is provided with a seat cushion and a seat back, and each of the seat cushion and the seat back is formed by a central part, and a pair of side parts which are interchangeable. By selecting the side parts of the seat cushion and/or the seat back, the vehicle seat can be adapted to the need of a user. Also, if the side parts are worn or damaged, they can be replaced with new ones. 
     However, according to this prior art, replacing and installing side parts require some work. Also, if the seat contains any electric device, replacing or installing side parts requires rewiring of the electric device. This also complicates the replacing or installing work. 
     Therefore, there is a need for a novel vehicle seat that can be adapted to the need of a user in a simpler manner. 
     In a vehicle seat disclosed in JP2009-119230A, the shape and the softness of a support surface of the vehicle seat can be adjusted. A plurality of air bladders are incorporated in the seat cushion and the seat back and pressure sensors are arranged over a support surface of the vehicle seat. The air bladders are connected to an air pump, and a control device controls the air pressure supplied to each air bladder by supplying an appropriate pressure from the pump to each air bladder according to the output signals of the pressure sensors. 
     According to this prior art, in order to adjust the distribution of softness finely over the support surface, it is necessary to arrange a large number of small air bladders over the entire area of the support surface. Therefore, piping for the air bladders becomes highly complex, and supplying air pressure to each bladder requires a highly complex control arrangement. 
     Therefore, there is a need for a novel vehicle seat that can adjust the distribution of the softness of a support surface thereof in a simpler manner. 
     For environmental considerations, various systems of car pooling or ride sharing have been proposed. In a car sharing system proposed in JP2014-215670A, fellow passengers are selected from those who trust one another. Trustworthiness is evaluated on the basis of personal relationships which may be manifested in the listing of addresses in a personal terminal device of each user. If a subject user&#39;s address is listed in the personal terminal of a first user, the subject user and the first user may be considered to be trustworthy each other by a first degree. If a subject user&#39;s address is listed in the personal terminal of a first user, and the first user&#39;s address is listed in a second user, the subject user and the second user may be considered to be trustworthy to each other by a second degree. 
     This system preferentially selects users who are relatively familiar to each other, but this does not ensure that the two users are on a friendly term or able to sit together comfortably. 
     Therefore, there is a need for a passenger selection system that can select fellow passengers in a ride share system so as to optimize of the comfort of each passenger. 
     SUMMARY OF THE INVENTION 
     In view of such problems of the prior art, a primary object of the present invention is to provide a vehicle seat that is provided with interchangeable seat parts that can be readily changed while allowing electric connection to be achieved at the same time in an effortless manner. 
     A second object of the present invention is to provide a vehicle seat that can adjust the stiffness of a pressure receiving surface thereof for the maximum comfort of the seat occupant. 
     A third object of the present invention is to provide a passenger selection system for a ride share that can optimize the comfort of the user by selecting fellow passengers by using data obtained from a biometric sensor incorporated in the seat. 
     To accomplish at least some of such objects, a first aspect of the present invention provides a vehicle seat, comprising: a frame member provided on a floor of a vehicle; a seat part detachably attached to the frame member; a mechanical connector device provided on the frame member and the seat part for detachably attaching the seat part to the frame member; and an electric connector device provided on the frame member and the seat part for electrically connecting an electric component provided on the seat part to an electric component provided on the frame member. 
     Thereby, the seat part, such as a seat cushion, a seat back and a head rest, can be readily attached to and removed from the seat frame both mechanically and electrically in a highly simple and effortless manner so that the seat can be adjusted to the need of the user in a convenient manner. The electric connection as used herein should not be limited to literal electric connection, but should be understood to mean any mode of arrangement for enabling transmission of power and/or signals in optical, acoustic or any other form. 
     Preferably, the electric connector device is integrally incorporated in the mechanical connector device. 
     Thereby, the attachment and detachment of the seat part to and from the frame member are maximally simplified. 
     According to a preferred embodiment of the present invention, the mechanical connector device is provided with a first tube provided on the seat part, and a second tube provided on the frame member and configured to be fitted into or onto the first tube, and the electric connector device includes a first part received in the first tube and a second part received in the second tube. 
     By fitting one of the tubes into or onto the other, a highly mechanical connection can be achieved by using a highly simple structure. A suitable latch mechanism may be used to further enhance the stability of the mechanical connection. By placing the electric connector device in these tubes, the electric connector device can be protected from damages from external forces and foreign matters. 
     In a particularly preferred embodiment of the present invention, the first part of the electric connector device is provided with an identifier carrying prescribed information, and the second part of the electric connector device is provided with a recognition device configured to read information carried by the identifier. 
     Thereby, the attributes of each seat part can be identified as soon as the seat part is joined to the frame member so that the control device of the vehicle is enabled to control the seat part or any devices associated therewith in a proper manner without requiring any human intervention. 
     In a certain embodiment of the present invention, the seat part includes at least a first seat part segment which is detachably attached to the frame member via the mechanical connector device and the electric connector device, and a second seat part segment which is detachably attached to the first seat part segment via a segment mechanical connector device provided on the first seat part segment and the second seat part segment. 
     Thereby, the seat can be adapted to the user in a finely adjusted manner. Also, the seat can be repaired by replacing a damaged part thereof, instead of replaying the entire seat. 
     According to another aspect of the present invention, the electric component provided on the seat part includes a plurality of pressure sensors arranged over a pressure supporting surface of the seat part and each configured to detect a pressure applied thereto, and a plurality of actuators arranged over the pressure supporting surface of the seat part and each configured to change a localized stiffness of the pressure supporting surface of the seat part, and the electric component provided on the frame member includes a control device or a wiring leading to a control device, the control device being configured to control operation of the actuators according to output signals from the pressure sensors. 
     Thereby, the level of stiffness of various parts of the pressure receiving surface can be adjusted so as to optimize the comfort and support of the seat occupant. 
     In a particularly preferred embodiment of the present invention, the seat part includes a sub frame configured to be detachably attached to the frame member, a pad supported by the sub frame and a skin member covering a surface of the pad, and the actuators are interposed between the skin member and the pad. 
     Thereby, the actuators are protected from damages, and the change in stiffness caused by each actuator can be transmitted favorably to the seat occupant. 
     Preferably, the pressure sensors are incorporated in a pressure sensor sheet interposed between skin member and the pad. 
     Thereby, the pressure sensors can detect the pressure values in an accurate manner, and can be installed in a highly simple manner. The pressure sensors may be incorporated in the skin member to further enhance these advantages. The actuators may also be incorporated in a soft actuator sheet interposed between the skin member and the pad. 
     Preferably, the soft actuator sheet comprises linear actuators extending in a lateral direction of the seat part and arranged in a longitudinal direction of the seat part, and each configured to change a tension thereof according to an input signal supplied thereto. 
     Thereby, the pressure actuators can be prepared and installed in a simple manner, and the stiffness variations in the longitudinal direction can be produced in an effective and simple manner. 
     The soft actuator sheet may further comprise linear actuators extending in the longitudinal direction of the seat part and arranged in the lateral direction of the seat part, and each configured to change a tension thereof according to an input signal supplied thereto. 
     Thereby, the stiffness variations in the pressure support surface in the longitudinal direction can be produced in an effective and simple manner. 
     To further simplify the arrangement, the pressure sensors may comprise linear pressure sensors incorporated in the soft actuator sheet. Thereby, the structure for the pressure sensors can be simplified. 
     Preferably, the pad and/or the sub frame is provided with a recess configured to receive wiring leading from the electric component provided on the seat part to the electric connector device provided on the seat part. 
     Thereby, the wiring can be passed through the seat part without impairing the seating comfort of the seat part. 
     A third aspect of the present invention provides a passenger selection system including the vehicle seat according to the first aspect of the present invention, the system comprising: a detection unit including a biometric sensor provided on the seat part and configured to detect an index pertaining to emotion of each user seated in the seat to a fellow passenger sharing a ride with the user; a storage unit for storing a history of the indices of the user in relation to the fellow passengers detected during rides that were shared in the past; and a computation unit for selecting a fellow passenger for a next ride to be shared by the user according to the history stored in the storage unit. 
     Thereby, the users are enabled to share vehicles with maximum comfort in a subtle way. Since the biometric sensor is provided on the seat part, the users are not required to wear any device on their persons, and the comfort and convenience of the users can be maximized. 
     Preferably, the storage unit and the computation unit are provided in a data center provided separately from the vehicle. Thereby, the data can be processed and controlled centrally so that the risk of leaking personal data can be minimized. 
     The vehicle may be provided with a wireless transmitter for sending detection results of the biometric sensor to the data center. Thereby, the data can be transmitted to the data center promptly. 
     Preferably, the computation unit is configured to analyze the history of the indices stored in the storage unit, and select a fellow passenger for a next ride to be shared by the user according to an analysis result. 
     Thereby, the process of selecting the fellow passengers can be performed in an automated manner. In this conjunction, the computation unit may be configured to select a fellow passenger for the user from those to whom the user registered higher levels of emotion than others as recorded in the history. Alternatively, the computation unit may be configured to select a fellow passenger for the user by eliminating those to whom the user registered lower levels of emotion than others as recorded in the history. 
     According to another aspect of the present invention, the computation unit is configured to group the users of the system into a plurality of groups such that the users in each group register high emotional level toward each other, and select a fellow passenger for each user from the group to which the particular user belongs. 
     This arrangement also allows each user to share rides with fellow passengers the user is most comfortable to share a ride with. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING(S) 
         FIG. 1  is a perspective view of a vehicle seat according to a first embodiment of the present invention; 
         FIG. 2  is an exploded perspective view of the vehicle seat; 
         FIG. 3  is a perspective view of the vehicle seat formed by connecting two seat part segments; 
         FIG. 4  is a sectional view of a connector unit of the vehicle seat; 
         FIG. 5  is a block diagram of the internal structure of the vehicle seat; 
         FIG. 6  is an exploded perspective view of a vehicle seat given as a modification of the vehicle seat of the first embodiment; 
         FIG. 7  is a perspective view of a vehicle seat according to a second embodiment of the present invention; 
         FIG. 8  is an exploded perspective view of the vehicle seat; 
         FIG. 9  is a perspective view of the vehicle seat formed by connecting two seat segments; 
         FIG. 10  is an exploded perspective view of a seat cushion of the vehicle seat; 
         FIG. 11  is a cross sectional view of the seat cushion; 
         FIG. 12  is a view similar to  FIG. 10  showing a seat cushion based on a modification of the second embodiment; 
         FIG. 13  is a view similar to  FIG. 10  showing a seat cushion based on another modification of the second embodiment; 
         FIG. 14  is a view similar to  FIG. 10  showing a seat cushion based on yet another modification of the second embodiment; 
         FIG. 15  is a view similar to  FIG. 10  showing a seat cushion based on yet another modification of the second embodiment; 
         FIG. 16  is a view similar to  FIG. 7  showing yet another modification of the second embodiment; 
         FIG. 17  is a block diagram of a passenger selection system according to an embodiment of the present invention; and 
         FIG. 18  is a flowchart showing a control action of the passenger selection system. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     Preferred embodiments of the present invention are described in the following with reference to the appended drawings. The directions as used in the following disclosure are based on the view point of the vehicle occupant in the seat. 
     As shown in  FIGS. 1 to 3 , the seat  1  includes a frame member  2  supported by a floor F of a vehicle, and seat parts that are supported by the frame member  2 . The seat parts include a seat cushion  5 , a seat back  6  and a head rest  7 . The seat cushion  5  supports an occupant from below, and the seat back  6  extends upward from the rear end of the seat cushion  5  to support the back of the occupant. The head rest  7  extends upward from the upper end of the seat back  6  to support the head of the occupant from behind. The seat cushion  5  is provided with a sub frame  5 A, a pad  5 B supported by the sub frame  5 A, and a skin member  5 C covering the pad  5 B. Similarly, the seat back  6  is provided with a sub frame  6 A, a pad  6 B supported by the sub frame  6 A, and a skin member  6 C covering the pad  6 B, and the head rest  7  is provided with a sub frame  7 A, a pad  7 B supported by the sub frame  7 A, and a skin member  7 C covering the pad  7 B. In the illustrated embodiment, each sub frame is made of a sheet member or a plate member made of metal or plastic material. 
     The frame member  2  includes a lower frame part  2 A extending in a fore and aft direction, and an upper frame part  2 B extending substantially upward from the rear end of the lower frame part  2 A. The lower frame part  2 A and the upper frame part  2 B are each made of a hollow tubular member defining an inner space  2 C. In the illustrated embodiment, each tubular member is provided with a rectangular cross section, but may also be provided with a circular, polygonal or any other shape. The lower frame part  2 A is attached to the floor F via a plurality of legs  11 . These legs  11  may be either directly attached to the floor F or via a slide rail system that allows the fore and aft adjustment of the seat  1 . As shown in  FIG. 3 , the rear end of the lower frame part  2 A is formed with a connecting hole  12  passed laterally across the lower frame part  2 A. A plurality of similar seats may be joined to each other by using a connecting member  13  extending laterally and passed into the connecting holes  12  of the seats or seat segments to be connected to each other. The connecting member  13  may be attached to the floor F via a bracket (not shown in the drawings), for instance. 
     As shown in  FIG. 2 , the seat cushion  5 , the seat back  6  and the head rest  7  are both mechanically and electrically (or optically) connected to the frame member  2  via a connector unit  20 . The connector unit  20  includes a plurality of frame side connectors  21  and corresponding seat part side connectors  22  provided on the respective seat parts. 
     As shown in  FIG. 4 , each frame side connector  21  includes a base portion  24  attached to the frame member  2 , and a first tube  26  supported by the base portion  24  via a cushion element  25 . The base portion  24  is attached to the frame member by welding or fastening. The first tube  26  has an open end facing away from the frame member and a closed bottom end. 
     The cushion element  25  may consist of an elastic member such as rubber. Alternatively, the cushion element  25  may consist of an air damper, an electromagnetic damper, an oil damper or the like. When the cushion element  25  consists of an air damper, the air damper may be provided with an air chamber which functions as an actuator by expanding and contracting by the supply and the release of compressed air into and out of the air chamber. The air chamber may be expanded and contracted by receiving and releasing air according to the vibrations transmitted from the vehicle so as to function as an active damper (active suspension system) that cancels the vibrations of the vehicle. The oil damper may consist of a viscoelastic variable damper. 
     The bottom end of the first tube  26  is internally provided with first connecting members  28  for electrically or optically connecting to counterparts (which will be described hereinafter) provided on the corresponding seat part, and a recognition device  32  for identifying an identifier  31  (which will be described hereinafter). The lead wires of the first connecting members  28  and the recognition device  32  are bundled together, and extend into the frame member  2  through the bottom end of the first tube  26 , the cushion element  25  and the base portion  24 . 
     Each seat part side connector  22  includes a second tube  35  connected to the corresponding sub frame  5 A,  6 A,  7 A. The second tube  35  has an open end facing away from the corresponding sub frame  5 A,  6 A,  7 A and a closed bottom end remote from the open end. 
     The bottom end of the second tube  35  is internally provided with second connecting members  36  for electrically or optically connecting to the corresponding first connecting members  28 , and an identifier  31 . The wiring connected to the second connecting members  36  extends into the corresponding seat part ( 5 ,  6 ,  7 ) through the bottom end of the second tube  35  and the sub frame  5 A,  6 A,  7 A. 
     In the illustrated embodiment, the second tube  35  is configured to fit into the first tube  26 . In other words, the first tube  26  is an outer tube, and the second tube  35  is an inner tube. Alternatively, the first tube  26  may be an inner tube while the second tube  35  is an outer tube. A locking recess  41  is formed on the outer surface of the first tube  26 , and a locking claw  42  is pivotally provided on the outer surface of the second tube  35  so that the first tube  26  and the second tube  35  may become attached to each other by the locking claw  42  engaging the locking recess  41 . The locking claw  42  is urged by a biasing member such as a torsion coil spring (not shown in the drawings) into engagement with the locking recess  41 . By manually operating the locking claw  42 , the first tube  26  and the second tube  35  can be detached from each other. If desired, the first tube  26  and the second tube  35  may be provided with a non-circular cross section such as a polygon and an ellipsis so that the first tube  26  and the second tube  35  may not be rotated around the axial line relative to each other. The first tube  26  and the second tube  35  which can be detachably connected to each other thus jointly form a mechanical connector  38  for mechanically connecting the corresponding seat part to the frame member  2 . 
     An annular seal member  45  is retained on the outer periphery of the second tube  35  to provide a liquid tight seal between the outer circumferential surface of the second tube  35  and the inner circumferential surface of the first tube  26 . 
     When the first tube  26  and the second tube  35  are connected to each other, the first connecting members  28  and the second connecting members  36  are electrically or optically connected to each other. The first connecting member  28  and the second connecting member  36  may consist of electric connectors that are electrically connected to each other by contact, optical fiber connectors that are optically connected each other when connected, or coils or other devices that are magnetically connected to each other without contact. When the first tube  26  and the second tube  35  are connected to each other, the first connecting member  28  and the second connecting member  36  are positioned inside the second tube  35 . 
     When the first tube  26  and the second tube  35  are connected to each other, the recognition device  32  opposes the identifier  31  so that the recognition device  32  recognizes the identifier  31 . The identifier may consists of image information such as a bar code or an IC tag, the recognition device  32  may consist of a camera that can read image information such as a bar code or an IC tag reader for reading IC tags. The information contained in the identifier  31  may be information on the size and shape of the corresponding seat part, or information on an electric component  47  provided on the corresponding seat part. 
     As shown in  FIG. 2 , each seat part is preferably connected to the frame member  2  via a plurality of connector units  20  such that the seat part is prevented from rotating relative to the frame member  2 . In the illustrated embodiment, the seat cushion  5  and the seat back  6  are each connected to the frame member  2  via three connector units  20 . The connectors  22  on each seat part  5 ,  6 ,  7  are each positioned laterally central part thereof. Thus, the frame member  2  is positioned laterally centrally with respect to the seat part  5 ,  6  and  7 . 
     As shown in  FIGS. 2 and 5 , the inner space  2 C of the frame member  2  receives a control device  50  which is one form of electric device. The control device  50  consists of an electronic control unit comprising a circuit board supporting CPU, memory and other components and fixedly attached to the inner surface of the frame member  2 . The control device  50  is connected to an onboard power source  52  via a power cable  51 . The power cable  51  extends to the power source  52  via the inner space  2 C of the frame member  2  and the interior of one of the legs  11 . The control device  50  is connected to the first connecting members  28  and the recognition devices  32  of the frame side connectors  21  via signal wires  33  and  34 . If the cushion element  25  consists of an active element such as an air damper, the control device  50  is connected the cushion element  25  via signal wires. In an alternate embodiment, the frame member  2  is made of electrically insulating material, and the circuit pattern of the control device  50  is directly provided on the inner surface of the frame member  2 . In such a case, the frame member  2  and the control device  50  may be combined into a single integral component so that the number of component parts can be reduced, and weight reduction can be accomplished. 
     Each seat part may be provided with an electric component  47  which may consist of any electric component such as a heater, a cooling fan, a temperature sensor, a humidity sensor, a pressure, an air bag, a switch and an actuator. The electric component  47  may be provided between the sub frame  5 A,  6 A,  7 A and the pad or between the pad and the skin member  5 C,  6 C,  7 C. The electric component provided on the seat part is electrically connected to the second connecting member via wires  37 , and thence to the control device  50  via the connector unit  20  and the signal wires  33 . 
     In the illustrated embodiment, each seat part can be interchangeably selected from a number of selections having different sizes and configurations, different properties of the pad and the skin member, and the kinds of the electric component  47 , and connected to the frame member  2  via the connector unit  20 . For instance, the seat cushion  5 , the seat back  6  and the head rest  7  can be selected from preselected standard products based on the standard body sizes and shapes of an adult male, an adult female, a child and an infant. 
     The inner space  2 C of the upper frame part  2 B receives an air bag device  60  which includes a folded air bag and an inflator for inflating the air bag at the time of a crash. A rear end of the upper frame part  2 B is provided with an opening through which the air bag can be deployed. This air bag is intended to protect an occupant seated in a seat behind the seat in question from hitting the seat in question. Because the air bag device is provided directly on the frame member  2  having a relatively high stiffness, instead of the seat part, the air bag can be deployed in a stable manner. The opening may be provided with a lid that is configured to the displaced or fractured under the pressure from the deploying air bag. 
     The inflator of the air bag is electrically connected to the control device  50  via wires  63  passed through the inner space  2 C of the frame member  2 . The control device  50  is configured to activate the air bag device  60  according to a signal from a crash detection sensor  65  such as an acceleration sensor. 
     Side parts of the seat cushion  5  and the side parts of the seat back  6  are each provided with a correction device  70  for forcing the occupant to a proper seating posture at the time of a vehicle crash. The proper seating posture means that the occupant&#39;s buttocks are centrally positioned on the seat cushion  5  and the occupant&#39;s back is also centrally positioned on the seat back  6 , both laterally and longitudinally, so that the occupant may withstand the deceleration of a vehicle crash in an optimum fashion. Each correction device  70  may include an air cylinder for moving the corresponding part of the seat part. The correction device  70  may be considered as a form of the electric component  47 , and is electrically connected to the corresponding second connecting member  36  via wires  37  to be connected to the control device  50  via the connector unit  20 . The control device  50  controls the correction device  70  according to the signal from the crash detection sensor  65 . 
     Thus, the seat parts such as the seat cushion  5 , the seat back  6  and the head rest  7  can be detachably attached to the frame member  2  so that the seat  1  can be adapted to the occupant simply by selecting the seat parts accordingly. 
     Because the connector unit  20  allows the seat parts to be both electrically and mechanically connected to the frame member  2 , installing and replacing the seat parts can be accomplished in an effortless manner. 
     Because each connector unit  20  can be connected by fitting the second tube  35  into the first tube  26 , the first connecting member  28  and the second connecting member  36  are protected from damages owing to an external force and contamination by moisture and other foreign matters. 
     The control device  50  identifies each identifier  31  with the corresponding recognition device  32  so that the control device  50  is able to acquire information on the particular seat part connected to the frame member  2 . Therefore, the control device  50  is enabled to control the electric component  47  incorporated in the corresponding seat part in a correct manner. 
     Each connector unit  20  may be configured to transmit both signals and electric power between the control device  50  provided on the frame member  2  and the electric component  47  incorporated in each seat part via the corresponding connector unit  20 . 
     In a modified embodiment, at least one of the seat parts consist of a plurality of seat part segments. For instance, as shown in  FIG. 6 , the seat cushion  5  may consist of a laterally central part  71  and a pair of side parts  72  detachably connected to either side of the central part  71 . The central part  71  and the side parts  72  are each provided with a sub frame, a pad and a skin member, individually. The central part  71  is detachably connected to the frame member  2  via a first connector unit  20 . Each side part  72  is detachably connected to the central part  71  via a second connector unit  74  which connects the two parts both mechanically and electrically, and may be similar to the aforementioned connector units  20 . Each of the central part  71  and the side parts  72  may be provided with an electric component  47 . The electric component  47  provided on either one of the side parts  72  may be connected to the control device  50  provided in the frame member  2  via the second connector unit  74 , the central part  71  and the first connector unit  20 . 
     In the foregoing embodiment, the first tube  26  of at least one of the connector units  20  may be connected to the base portion  24  via a hinge, a ball joint or any other movable joint. Also, a resilient member may be provided on any of the connector units  20  for urging the first tube  26  to an initial position relative to the corresponding base portion. 
       FIGS. 7 to 11  show a second embodiment of the present invention. As shown in  FIGS. 7 to 9 , the seat  101  includes a frame member  102  supported by a floor F of a vehicle, and seat parts that are supported by the frame member  102 . The seat parts include a seat cushion  105 , a seat back  106  and a head rest  107 . The seat cushion  105  supports an occupant from below, and the seat back  106  extends upward from the rear end of the seat cushion  105  to support the back of the occupant. The head rest  107  extends upward from the upper end of the seat back  106  to support the head of the occupant from behind. The seat cushion  105  is provided with a sub frame  105 A, a pad  105 B supported by the sub frame  105 A, and a skin member  105 C covering the pad  105 B. Similarly, the seat back  106  is provided with a sub frame  106 A, a pad  106 B supported by the sub frame  106 A, and a skin member  106 C covering the pad  106 B, and the head rest  107  is provided with a sub frame  107 A, a pad  107 B supported by the sub frame  107 A, and a skin member  107 C covering the pad  107 B. In the illustrated embodiment, each sub frame is made of a sheet member or a plate member made of metallic or plastic material. 
     The frame member  102  includes a lower frame part  102 A extending in a fore and aft direction, and an upper frame part  102 B extending substantially upward from the rear end of the lower frame part  102 A. The lower frame part  102 A and the upper frame part  102 B are each made of a hollow tubular member. In the illustrated embodiment, each tubular member is provided with a rectangular cross section, but may also be provided with a circular, polygonal or any other shape. The lower frame part  102 A is attached to the floor F via a plurality of legs  110 . As shown in  FIG. 3 , the rear end of the lower frame part  102 A is formed with a connecting hole  108  passed laterally across the lower frame part  102 A. A plurality of similar seats may be joined to each other by using a connecting member  109  extending laterally and passed into the connecting holes  108  of the seats to be connected to each other. The connecting member  109  may be attached to the floor F via a bracket (not shown in the drawings), for instance. 
     As shown in  FIG. 10 , a pressure sensor sheet  114  for detecting a pressure applied thereto and an actuator sheet  118  for changing the stiffness (softness) of the seat cushion  103  are interposed between the skin member  103 C and the pad  103 B of the seat cushion  103 . In an embodiment of the present invention, the pressure sensor sheet  114  and the actuator sheet  118  are incorporated in a single sheet. The pressure sensor sheet  114  and the actuator sheet  118  are primarily formed of fabric sheets, and cover the upper surface or the support surface X of the pad  103 B supporting the load from the occupant. As the pressure sensor sheet  114  and the actuator sheet  118  extend along the support surface X, the pressure sensor sheet  114  detects the load acting on the support surface X, and the actuator sheet  118  changes the stiffness of the seat cushion  103  immediately under the support surface X. 
     The pressure sensor sheet  114  includes a plurality of pressure sensors  112  arranged over a detection surface Y of the pressure sensor sheet  114  in a grid pattern and each consisting of a device that changes an electric property such as resistance and capacitance according to the load applied perpendicularly on the detection surface Y of the pressure sensor sheet  114 . By analyzing the output signals from the individual pressure sensors  112 , the distribution of the pressure applied to the detection surface Y can be obtained. In the illustrated embodiment, the pressure sensor sheet  114  includes a substrate consisting of a film, lower electrodes arranged on the film in the grid pattern, electroconductive rubber material deposited on the upper surfaces of the lower electrodes, and upper electrodes opposing the lower electrodes via the electroconductive rubber material. The upper electrodes and the lower electrodes each consisting of a square film having a side measuring a few millimeters to a few centimeters oppose each other with a gap in the order of a few millimeters defined therebetween. The electric resistance of the rubber material between each upper electrode and the corresponding lower electrode changes in dependence on the pressure applied to the upper electrode in a direction perpendicular to the detection surface Y. Since the pressure sensor sheet  114  consists of a flexible sheet, the pressure sensor sheet  114  can conform to the surface contour of the support surface X which changes depending on the load applied thereto by the occupant. The pressure sensor sheet  114  is not limited to the one described here, but may consist of any other pressure sensor in the form of a sheet, such as a piezoelectric sensor sheet having piezoelectric fibers woven therein, and a capacitive sensor sheet including a deformable film interposed between a pair of electrodes. Lead wires  120  connected to the individual pressure sensors  112  extend from side edges of the pressure sensor sheet  114  (three wires from each lateral edge in the illustrated embodiment). 
     The actuator sheet  118  includes a plurality of laterally extending linear soft actuator  116 W, a plurality of warps  152 L made of fibers and a plurality of woofs  152 W also made of fibers. Each soft actuator  116 W consists of a filament that extends laterally across the actuator sheet  118  and shrinks depending on a voltage applied thereto. In the illustrated embodiment, each soft actuator  116 W is made of a shape memory alloy, and has a diameter of several tens of micrometers to several hundreds of micrometers. The soft actuator  116 W may also consist of electroconductive high polymer, carbon-based material or magnetic fluid that changes shape according to a magnetic field created by an applied voltage. As shown in the enlarged view of  FIG. 10 , the soft actuators  116 W are woven with the warps  152 L. Therefore, the soft actuators  116 W can be arranged along the surface of the actuator sheet  118  without any difficulty, and are prevented from moving within the actuator sheet  118 . 
     A plurality of sheet connectors  119  are arranged along the lateral edges of the actuator sheet  118 . The soft actuators  116 W are electrically connected to these sheet connectors  119 . 
     The pressure sensor sheet  114  and the actuator sheet  118  cover the pad  103 B, and are attached to the sub frame  103 A at the peripheral edges thereof by being interposed between the sub frame  103 A and the pad  103 B. The effective detecting area of the pressure sensor sheet  114  or the detection surface Y may be provided only on the part of the pressure sensor sheet  114  covering the upper surface of the pad  103 B. In the illustrated embodiment, the actuator sheet  118  adjoins the skin member  103 C. The sheet connectors  119  are connected to lead wires  122 . 
     In particular, the soft actuator sheet  118  is fixedly attached to the sub frame  103 A via the sheet connectors  119  in the illustrated embodiment. When an electric voltage is applied to the soft actuator sheet  118 , the tension in the soft actuator sheet  118  increases. As a result, the support surface X may be elevated as a result as shown by the imaginary lines in  FIG. 11 . When the tension in the soft actuator sheet  118  increases, the reaction to the downward load on the seat cushion  103  for a given load increases. In other words, the stiffness of the support surface X of the seat cushion  103  increases. Thus, the stiffness or rigidity of the support surface X of the seat cushion  103  can be changed by applying a different voltage to the soft actuator sheet  118 . 
     The upper surface of the sub frame  103 A is provided with a plurality of grooves  130  (six grooves in the illustrated embodiment) each extending from a lateral edge to a laterally central part of the sub frame  103 A. The grooves  130  extending from either lateral edge are aligned in pairs. The pad  103 B is provided with recesses  131  opposing the respective grooves  130  so that laterally extending passages  132  are defined between the pad  103 B and the sub frame  103 A. The wires  120  and  122  are passed through these passages  132  so that the occupant seated on the seat cushion  103  is prevented from experiencing any discomfort owing to the presence of the wires  120  and  122 , and the external appearance of the seat  101  can be enhanced. 
     The inner end of each groove  130  is formed with a through hole  134  passed through the sub frame  103 A, and the wires  122  and  122  are received in the groove  130  and passed through the through hole  134 . The upper surface of the frame lower part  102 A are provided with first connectors  142  which project upward. A plurality of second connectors  140  that are configured to be connected to the corresponding first connectors  142  provided on the frame lower part  102 A are attached to or otherwise provided on central parts of the lower surface of the sub frame  103 A. The wires  120  and  122  extending out of the through holes  134  are connected to terminal pieces of the second connectors  140 . 
     The first connectors  142  that project upward are configured to be mechanically and electrically connected to the corresponding second connectors  140  that project downward. Wires  144  connected to terminal pieces of the first connectors  142  are passed through the inner space  102 C of the frame lower part  102 A, and are connected to a control device  150  provided on an appropriate part of the floor F. 
     The control device  150  consists of an electronic control unit provided with a central processing unit and memory, and, as shown in  FIG. 10 , is connected to the pressure sensors  112  and the soft actuators  116 W via the wires  120 ,  122  and  144 . The control device  150  is configured to detect the pressures applied to the pressure sensors  112  from the changes in the electric properties of the respective pressure sensors  112 . The control device  150  further applies appropriate voltages to the respective soft actuators  116 W according to the magnitude and the distribution of the pressure applied to the pressure sensors  112 . 
     The mode of operation of the seat  101  is described in the following. The occupant in the seat  101  applies uneven pressure to the support surface X of the seat cushion  103 . For instance, a rear part of the support surface X receives a greater pressure from the buttocks of the occupant while a front part of the support surface X receives a relatively small pressure. Therefore, it is desirable if the rear part of the seat cushion  103  is made softer than the front part of the seat cushion  103 . 
     The control device  150  computes the distribution of pressure on the detection surface Y according to the output signals from the pressure sensors  112 . At this time, the detection surface Y is divided into a plurality of rectangular areas, for instance  10  by  10  rectangular areas, and the pressure applied to each rectangular area is compared with the average value of the pressure applied to the entire detection surface Y. The control device  150  drives the soft actuator  116 W located under each rectangular area according to the difference between the pressure applied to this particular rectangular area and the average pressure. For instance, when the pressure applied to a certain rectangular area is greater than the average pressure value, the soft actuator  116 W located under this rectangular area is extended so that this rectangular area is made comparatively softer. Conversely, when the pressure applied to a certain rectangular area is smaller than the average pressure value, the soft actuator  116 W located under this rectangular area is contracted so that this rectangular area is made comparatively harder or stiffer. By thus adjusting the softness or the stiffness of the different parts of the support surface X, the sitting comfort for the occupant can be enhanced. 
     In this embodiment, each rectangular area may consist of a square having a side which may range between several millimeters to several centimeters, and such squares are arranged in a grid pattern. Therefore, the distribution of pressure on the detection surface Y can be detected with a corresponding resolution. Also, because the soft actuators are in a linear form having a diameter that may range between several tens of micrometers and several hundreds of micrometers, the distribution of the stiffness or softness of the support surface X can be controlled with a corresponding resolution. 
     In the illustrated embodiment, the soft actuators  116 W are arranged in the longitudinal direction (in the fore and aft direction in the case of the seat cushion  103  and in the vertical direction in the case of the seat back  104 ) along which the variations in the pressure from the occupant are relatively significant. More specifically, in the case of the seat cushion  103 , by extending the soft actuators  116 W in a rear part of the seat cushion  103  and contracting the soft actuators  116 W in a front part of the seat cushion  103 , the front part can be made relatively stiff while the rear part is made relatively soft. Thereby, the rear part of the seat cushion  103  is caused to sink relatively easily so that the support surface X of the seat cushion  103  is enabled to conform to the lower end of the occupant, and the comfort to the occupant can be maximized. 
     Because the soft actuators  116 W can be electrically controlled, the softness of the seat cushion  103  can be controlled both easily and rapidly by using a simple arrangement. Because the soft actuators  116 W are provided between the skin member  103 C and the pad  103 B, the soft actuators  116 W are favorably protected from damages. Because the soft actuators  116 W are positioned immediately under the skin member  103 C, the support surface X of the seat cushion  103  is enabled to conform to the pressure distribution applied thereto by the occupant in a favorable manner. 
     By providing the pressure sensor sheet  114  immediately under the actuator sheet  118  and minimizing friction between the pressure sensor sheet  114  and the actuator sheet  118  by using suitable surface materials, the pressure sensor sheet  114  is prevented from deforming by the extension and contraction of the soft actuator sheet  116 W, and enabled to detect the pressure distribution on the detection surface Y in a favorable manner. 
     In a modified embodiment illustrated in  FIG. 12 , in addition to the laterally extending soft actuators  116 W, longitudinally extending soft actuators  116 L are arranged laterally. In particular, as shown in an enlarged view in  FIG. 12 , the laterally extending soft actuators  116 W and the longitudinally extending soft actuators  116 L are woven together. Therefore, the stiffness of the seat cushion  103  can be varied both along the lateral direction and the longitudinal direction or two-dimensionally. Therefore, it is possible to vary the stiffness of the seat cushion  103  in a highly localized manner. For instance, the laterally extending soft actuators  116 W and the longitudinally extending soft actuators  116 L in the parts of the seat cushion  103  corresponding to the ischia and/or tailbone of the occupant may be extended so as to soften the corresponding regions. Thereby, the softness distribution of the support surface X of the seat cushion  103  can be more finely adjusted. Also, because the laterally extending soft actuators  116 W and the longitudinally extending soft actuators  116 L are woven together, the soft actuators  116 W and  116 L are prevented from moving relative to each other. 
     In this case, the sheet connectors  119  for the longitudinally extending soft actuators  116 L are attached to the front and rear edges of the actuator sheet  118 , and are also fixedly secured to the front and rear edges of the sub frame  103 A either directly or via the actuator sheet  118 . To accommodate the wires  122  connected to these sheet connectors  119 , grooves  30  extending in the fore and aft direction may be formed in the upper surface of the sub frame  103 A while the corresponding parts of the lower surface of the pad  103 B of the seat cushion  103  are provided with corresponding recesses  31 . 
     In another modified embodiment shown in  FIG. 13 , soft actuators  116 W and  116 L are directly incorporated in the skin member  103 C. As shown in an enlarge view in  FIG. 13 , the soft actuators consist of laterally extending soft actuators  116 W and longitudinally extending soft actuators  116 L that are woven to each other as wefts and warps, respectively. The pressure sensor sheet  114  is interposed between the skin member  103 C and the pad  103 B. In this embodiment also, the stiffness of the seat cushion  103  can be varied both along the lateral direction and the longitudinal direction or two-dimensionally. Therefore, it is possible to vary the stiffness of the seat cushion  103  in a highly localized manner. 
     Because the soft actuators  116 W and  116 L are incorporated in the skin member  103 C, the support surface X of the seat cushion  103  is enabled to conform to the pressure distribution applied thereto by the occupant in a favorable manner. 
     In a yet another modified embodiment shown in  FIG. 14 , pressure sensors  112  and soft actuators  116  in linear form are incorporated in the skin member  103 C, instead of using a pressure sensor sheet  114  and an actuator sheet  118 . Similarly as the embodiment illustrated in  FIG. 10 , the control device  150  determines the pressure distribution of the support surface X according to the signals from the pressure sensors  112 , and varies the distribution of stiffness of the support surface X by extending and contracting the selected soft actuators  116  according to the determined pressure distribution. Because the pressure sensors  112  and soft actuators  116  are all incorporated in the skin member  103 C, the assembly of the seat  101  is facilitated. The linear pressure sensors  112  may consist of piezoelectric fibers each including a core electrode, a flexible piezoelectric layer formed around the core electrode, and an outer electrode surrounding the piezoelectric layer. 
     In a yet another modified embodiment shown in  FIG. 15 , only soft actuators  116  are incorporated in the skin member  103 C, instead of using a pressure sensor sheet  114  and an actuator sheet  118 . In this case, the soft actuators  116  also serve as pressure sensors  112  each by generating a voltage according to a pressure applied thereto. By thus using devices that serve both as pressure sensors and soft actuators, the number of component parts of the seat  101  can be reduced. The control device  150  determines the pressure distribution of the support surface X according to the signals from the soft actuators  116 , and varies the distribution of stiffness of the support surface X by extending and contracting the selected soft actuators  116  according to the determined pressure distribution. The soft actuators  116  in this case may consist of electroconductive high polymer actuators using ionized liquid, for instance. 
     In the foregoing embodiment, the pressure sensors  112  and the soft actuators  116  are provided on the seat cushion  103 , but, alternatively or additionally, may be provided on the seat back  104 . In the case of this seat back  104 , the pressure sensors  112  and the soft actuators  116  or the pressure sensor sheet  114  and the soft actuator sheet  118  are provided on the seat back  104  or in particular on a support surface X defined on the front surface of the pad member  104 B as shown in  FIG. 16 . When only the laterally extending soft actuators  116 W are used, laterally extending soft actuators  116 W are arranged along the longitudinal direction of the seat back  104 . 
     In the foregoing embodiments, the pressure sensors  112  are configured to detect a pressure applied perpendicularly to the support surface X, but may also detect the pressure as a tension applied to each pressure sensor  112  extending along the support surface X. Since the increase in the tension is proportional to the pressure applied perpendicularly to the support surface X, the tension provides an accurate measure of the pressure applied to the support surface X. The pressure sensor sheet  114  and the soft actuator sheet  118  may also be attached to the upper surface and/or the side surfaces of the pad  103 B, instead of attaching the peripheral parts of the pressure sensor sheet  114  and the soft actuator sheet  118  to the sub frame  103 A. 
     In the foregoing embodiments, the soft actuator sheet  118  and the pressure sensor sheet  114  are interposed between the skin member  103 C and the pad  103 B in that order, but may also be reversed in order, by placing the pressure sensor sheet  114  on top of the soft actuator sheet  118 . In the latter case, the sensitivity of the pressure sensor sheet  114  can be improved. 
     In the foregoing embodiments, the channels  132  for receiving the wires  120  and  122  are defined by the grooves  130  formed in the sub frame  103 A and the recesses  131  formed in the pad member  103 B, but only the grooves  130  or the recesses  131  may be formed in the corresponding depending on the diameters of the wires  120  and  122 . 
       FIGS. 17 and 18  show a third embodiment of the present invention. A ride sharing system  201  for a vehicle  202  includes a detection unit  205  provided on the seat  203  (a seat cushion and a seat back of the seat  203 , respectively) and a data center  204  provided separately from the vehicle  202  typically at a fixed location. The detection unit  205  in this case essentially consists of a biometric sensor  205 . 
     The biometric sensor  205  is configured to detect indices relating to human emotion. The detection values of the indices detected by the biometric sensor  205  are forwarded to the data center  204  via a wireless communication between a transmitter provided on the vehicle  202  and a receiver provided on the data center  204 . The biometric sensor  205  detects indices for each of the occupants of the vehicle  202 . For example, the biometric sensor  205  may consist of a device for measuring the pulses, body temperature, brain waves and the like of an occupant of the seat  203 , a device for detecting liquid or gas secreted from the skin of an occupant such as perspiration and gases, and/or a device for measuring the electric conductance of the skin that can be changed by perspiration or the like. Other sensors may also be used as the biometric sensor  205 . The biometric sensor  205  may be fixedly attached to the seat  203  or the like of the vehicle  202  or may be portable like a wristband or the like that may be worn by the occupant. The biometric sensor  205  may be kept in contact with the occupant or may be positioned remotely from the occupant. 
     When the biometric sensor  205  is fixedly attached to the seat  203 , there is no need for the user to wear the biometric sensor  205 , and since the biometric sensor  205  is positioned close to the seated occupant, gas or the like secreted from the occupant&#39;s skin can be detected in a reliable manner. When the biometric sensor  205  is provided in the wristband, the biometric sensor  205  can be brought into contact with the skin of the occupant so that the detection or measurement of the pulse rate, body temperature, perspiration, and/or skin electrical resistance of the occupant can be facilitated. The biometric sensor  205  may consist of a single sensor, but may also consist of two or more biometric sensors in order to detect indices relating to two or more kinds of emotions of the occupant in order to improve the accuracy of obtained information. It is preferable that the detection values of the indices detected by the biometric sensor  205  be transmitted to the data center  204  by wireless transmission so that the emotion data can be transmitted from the biometric sensor  205  to the data center  204  both easily and quickly. 
     The data center  204  includes an information processing device such as a personal computer including a computation unit  206  and a storage unit  207 . The data center  204  is preferably provided separately or independently from the vehicle  202  so that the data may be centrally managed, and the risk of leakage of personal information may be minimized. The computation unit  206  includes an emotion level computation unit  208  that computes an emotion level (which may be favorable in one extreme and unfavorable in the other extreme) of each occupant toward each of the other occupants according to the values of the indices detected by the biometric sensor  205 , and a passenger selection unit  209  for selecting a combination of passengers based on the emotion levels. The storage unit  207  functions as an emotion history database  210  that stores the detected values of the indices detected by the biometric sensor  205  as data representing the emotion level of each passenger toward each of the passengers sharing the ride with the passenger in question in each instance of ride share, and an emotion level database  211  for storing the emotion levels computed and analyzed by the emotion level computation unit  208 . 
     Each user of the system  201  is provided with a user terminal  212  such as a smart phone and a personal computer that can communicate with the data center  204 . The user terminal  212  transmits the time, the start point and the destination, along with a user ID, entered by the user to the data center  204 , and receives a determined combination of passengers from the data center  204 . 
     The process of determining a combination of passengers for sharing a ride is described in the following with reference to the flowchart shown in  FIG. 18 . Each user of the system  201  performs a user registration, and acquires a user ID. 
     The data center  204  receives a user ID, and the time, the start point and the destination for a planned trip from each user terminal  212  (step ST 1 ). 
     The passenger selection unit  209  analyzes the time, the start point and the destination entered by each user, and determines a route for the vehicle, and a combination of candidate passengers who are going to share a ride with each of a plurality of vehicles (step ST 2 ). 
     The passenger selection unit  209  then selects the fellow passengers for each user based on the history of emotion levels of the user stored in the emotion level database  211  (step ST 3 ). Once the user begins the ride as specified by the data center  204 , the biometric sensor  205  starts measuring the emotion level of each of the passengers of the vehicle (step ST 4 ). The measured emotion levels are transmitted to the data center  204  (step ST 5 ). The data center  204  stores the received data in the history database  210 , and analyzes the received data. The analysis results are stored in the emotion level DB  211 . At the same time, the old data is discarded according to a predetermined rule (step ST 7 ). 
     In this embodiment, the higher an emotional level value is, the more favorable the emotion of the user toward a potential fellow passenger is. The passenger selection unit  209  may select a combination of passengers for sharing a ride in such a way that the average of the emotional level values of the combination of the passengers may be maximized. 
     For instance, suppose that there are six users who desire to share a ride by using two vehicles, and each vehicle is to be assigned to three of the entire users. In such an instance, each user demonstrates a certain emotion level in relation to the two fellow passengers during the shared ride. It is therefore impossible to determine how the emotional level of the user may be attributed to each of the fellow passengers from a single instance of a ride share. Therefore, by accumulating the history of emotion levels of each user toward the other users over the past ride share instances, it is possible to discern the emotion level of the user toward each of the remaining users. 
     Thus, in this case, the data center  204  is able to determine the emotion levels of each user toward the remaining five users, and determine the two fellow passengers who give rise to high emotional level values. 
     In this case, each vehicle gives rise to six emotional level values. In order to optimize the entire emotional levels, the three passengers for each vehicle may be selected such that the average of the six emotional level values is maximized. Preferably, the selection may also be made so that the average of the six emotional level values for one vehicle is not much different from that of the other vehicle. 
     Alternatively, the passenger selection unit  209  may select a combination of passengers for sharing a ride in such a way that the average of the emotional level values of one of the passengers is maximized. This particular passenger may be the one who is going to drive the vehicle, or the one who pays an extra charge. 
     Also, the passenger selection unit  209  may select a combination of passengers for sharing a ride in such a way that a worst combination of passengers may be avoided. For instance, the passenger selection unit  209  selects the passengers of the vehicles in the order of receiving requests for sharing a ride. Once a vehicle is filled, any additional user requesting a ride is assigned to a next vehicle. During this process, if there is any combination of two passengers which gives rise to an emotion level value lower than a prescribed value, the passenger selection unit  209  avoids this particular combination by moving one of the passengers to another vehicle. Thereby, a discomfort owing to an undesirable combination of passengers can be avoided. 
     In an alternate embodiment, the passenger selection unit  209  groups users into a plurality of groups in such a manner that any two users in a same group give rise to favorable emotion level values. When selecting the combination of each vehicle, the passenger selection unit  209  selects the combination of passengers for each vehicle so that passengers belonging to a same group may be preferentially assigned to a same vehicle. 
     The users then share rides with other users. The biometric sensor  205  on each vehicle detects the indices representing the emotion of each passenger, and the data obtained by the biometric sensor  205  is transmitted to the data center  204 . The data is associated with the user ID of each user, and the user ID of each fellow passenger. The obtained data is stored in the emotion history database  210  (step ST 6 ). New data is added to the existing data each time the subject user shares a ride with other users. In this embodiment, a limit is set on the amount of data stored for each user, and the oldest part of the data may be discarded as new data is obtained (or, in other words, the emotion history is updated each time the user shares a rider with other users) (step ST 7 ). 
     The current emotion levels of one user toward other users can be computed from the past history of the particular user toward the respective other users. The emotion level may be evaluated based on a single index or a plurality of indices. If only one index is used as the emotion level data, the emotional level data may be simply evaluated as an average value. If two or more indices are used as the emotion level data, a weighted average may be used as the emotional level data. 
     If desired, the emotion level data may be based on an emotion of a subject user toward a combination of two or more users. 
     When a user shares a ride with a new user with whom the subject user has never shared a ride, the emotion level toward the new user may be set to a freely selected initial value (a typical value, for instance). Alternatively, an emotion level of a subject user toward a new user may be based on the emotion level of another user toward the new user. The present application is applicable not only to automobiles but also to other modes of transportation such as buses, ships and aircraft.