Patent Publication Number: US-2023137120-A1

Title: Motorized furniture

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a continuation of U.S. application Ser. No. 16/639,834, filed Feb. 18, 2020, which is the National Phase under 35 U.S.C. § 371 of PCT/JP2018/044703, filed Dec. 5, 2018, and which claims priority to Japanese Patent Application No. 2018-044695 and Japanese Patent Application No. 2018-227422, the disclosures of each of which are here by incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present invention relate to a motorized furniture. 
     BACKGROUND ART 
     For example, there is a motorized furniture (such as a motorized bed or motorized chair) capable of changing its height and backrest inclination. For example, there is proposed technique of helping a user fall asleep by performing a back dropping motion when it is judged that the user falls into a sleeping state. Meanwhile, there is proposed technique of establishing an airway by dropping a headrest when snoring or apnea occurs. There is a demand for providing the user with more comfortable sleep. 
     CITATION LIST 
     Patent Literature 
     PTL 1: Japanese Patent Application Publication No. 2012-34979 
     PTL 2: Japanese Patent Application Publication No. 2005-270627 
     SUMMARY OF INVENTION 
     Technical Problem 
     The embodiments of the present invention provide a motorized furniture capable of offering more comfortable sleep. 
     Solution to Problem 
     A motorized furniture according to embodiments of the present invention includes a control unit. The control unit transitions to a first falling asleep operation at second time where the elapse of time since first time, where the sleep of a user of the motorized furniture is detected, is equal to or larger than a first time threshold. The control unit performs a second falling asleep operation when a variation of a signal corresponding to a biological signal of the user in a first period during the first falling asleep operation is smaller than the variation in a first prior period, which exists prior to the first period, during the first falling asleep operation or when the absolute value of a difference between the variation in the first period and the variation in the first prior period is smaller than a first variation threshold. In the second falling asleep operation, the control unit performs at least one of: an operation of decreasing the inclination of a section of the motorized furniture; an operation of decreasing the gap between the height of a head part of a mattress of the motorized furniture and the height of a waist part of the mattress; and an operation of decreasing the difference between the pressure in the head part and the pressure in the waist part. The embodiments provide a motorized furniture capable of offering more comfortable sleep. 
     Advantageous Effects of Invention 
     The embodiments of the present invention can provide a motorized furniture capable of offering more comfortable sleep. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic perspective view illustrating a motorized furniture according to a first embodiment of the present invention. 
         FIGS.  2 A to  2 F  are schematic diagrams illustrating control over the motorized furniture according to the first embodiment. 
         FIG.  3    is a block diagram illustrating the motorized furniture according to the first embodiment. 
         FIGS.  4 A and  4 B  are schematic diagrams illustrating operations of the motorized furniture according to the first embodiment. 
         FIG.  5    is a flowchart illustrating the operations of the motorized furniture according to the first embodiment. 
         FIG.  6    is a schematic perspective view illustrating a motorized furniture according to a second embodiment of the present invention. 
         FIGS.  7 A and  7 B  are schematic side views illustrating the motorized furniture according to the second embodiment. 
         FIGS.  8 A and  8 B  are schematic diagrams illustrating operations of the motorized furniture according to the second embodiment. 
         FIG.  9    is a flowchart illustrating the operations of the motorized furniture according to the second embodiment. 
         FIGS.  10 A and  10 B  are schematic diagrams illustrating operations of a motorized furniture according to a third embodiment of the present invention. 
         FIGS.  11 A and  11 B  are schematic diagrams illustrating the motorized furniture according to the embodiments. 
         FIGS.  12 A to  12 D  are schematic diagrams illustrating another motorized furniture according to the embodiments. 
         FIG.  13    is a schematic perspective view illustrating a motorized furniture according to another embodiment of the present invention. 
         FIG.  14    is a schematic diagram illustrating operations of the motorized furniture according to the embodiments. 
         FIG.  15    is another schematic diagram illustrating the operations of the motorized furniture according to the embodiments. 
         FIG.  16    is still another schematic diagram illustrating the operations of the motorized furniture according to the embodiments. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinbelow, embodiments of the present invention are described with reference to the drawings. 
     The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio between the sizes of parts, and the like are not necessarily the same as real ones. Even when the different drawings represent the same parts, their dimensions and the ratio between them may be represented in different ways from one drawing to another. 
     Throughout the specification of the present application and the drawings, the same components as ones already described in the previously mentioned drawings are given the same reference signs and their detailed description is omitted as appropriate. 
     First Embodiment 
       FIG.  1    is a schematic perspective view illustrating a motorized furniture according to a first embodiment of the present invention. 
     As illustrated in  FIG.  1   , a motorized furniture  310  according to the first embodiment includes a controlled unit  70 C. The controlled unit  70 C includes a movable unit  70 , for example. The controlled unit  70 C may include at least one of: the movable unit  70 ; a lighting unit  73   a ; and a temperature control unit  73   b  (such as a heater). 
     In this example, the motorized furniture  310  is provided with a control device  160 . The control device  160  can control the controlled unit  70 C of the motorized furniture  310  (such as the movable unit  70 ). The control device  160  is a remote controller of the motorized furniture  310 , for example. The control device  160  is a handy switch, for example. 
     The control device  160  is provided with a manipulation reception unit  20  (such as buttons or a touch panel). The manipulation reception unit  20  is configured to receive user&#39;s manipulation. The controlled unit  70 C (such as the movable unit  70 ) is controlled by user&#39;s operations on the manipulation reception unit  20 . 
     The control device  160  may have various functions such as: a lighting on/off function; a nurse/carer call function; or a power on/off function. 
     The motorized furniture  310  is used in a location such as a house. The motorized furniture  310  may alternatively be used in a location such as an accommodation facility, a hospital, or a nursing-care facility. 
     In this example, the motorized furniture  310  is a motorized bed. The movable unit  70  described above is provided on the motorized bed. The movable unit  70  includes a section  71 . A mattress (not illustrated in  FIG.  1   ) is placed on the section  71 . A user lies on the mattress. 
     The movable unit  70  includes sections such as: a back section  70   a ; an upper leg section  70   b ; a lower leg section  70   c ; and a height change section  70   h . The height change section  70   h  is a bed lifting device, for example. As in the example in  FIG.  1   , the movable unit  70  may further include a head section  70   d . The multiple sections (the back section  70   a , the upper leg section  70   b , the lower leg section  70   c , and the head section  70   d ) included in the section  71  can change their angles. 
     For example, the angle of the user&#39;s back can be changed by the operation of the back section  70   a . The angle of the knees can be changed by the operations of the upper leg section  70   b  and the lower leg section  70   c . The angle of the head part (or the height of the head part) of the user can be changed by the operation of the head section  70   d . These angles can change in conjunction with each other. These angles are angles relative to a frame  75  of the bed. The frame  75  is set substantially in parallel with the floor surface, for example. The above angles of the section  71  may be angles relative to the floor surface. In this example, casters  70   g  are arranged below the frame  75 . The casters  70   g  may be replaced with “legs”. 
     The height change section  70   h  can change the distance (height) between the floor surface and the bed surface. The height change section  70   h  may be capable of changing the height of the bed on the head side and the height of the bed on the foot side individually. This makes it possible to change the inclination of the whole bed surface. 
     An actuator is used for these sections of the movable unit  70 , for example. The operation of the movable unit  70  enables at least one of motions including: a “back raising” motion; a “knee raising” motion; a “height adjustment” motion; an “inclination” motion; and the like. The “inclination” motion includes at least done of a roll motion and a tilt motion. 
     The control device  160  is electrically connected to the controlled unit  70 C (the movable unit  70 , for example). A control circuit may be provided between the control device  160  and the movable unit  70 . The electrically connected state also includes such a case where another circuit is provided in between. 
     In the example of  FIG.  1   , the control device  160  is connected to the motorized furniture  310  via a cable  15 . The control device  160  may be connected to the motorized furniture  310  via wireless communication. The control device  160  may be capable of communicating with the controlled unit  70 C by any method. 
     The control device  160  is manipulated by the user or the like (the user or a carer of the user). This enables manual control over the controlled unit  70 C (the movable unit  70 , for example). 
     In the embodiment, automatic control is possible in addition to the manual control by the user. In the automatic control, the controlled unit  70 C (the movable unit  70 , for example) is controlled without operations by the user or the like, for example. This control is carried out by a control unit  42 , for example. In the example illustrated in  FIG.  1   , the control unit  42  is provided below the section  71 . The control unit  42  may be provided in the control device  160  (a remote controller or a handy switch). The control unit  42  may be provided at any location. 
     In the embodiment, the control unit  42  controls the controlled unit  70 C (the movable unit  70 , for example) based on a biological signal of the user. 
     The biological signal includes a signal (such as information) on the body movement of the user. The biological signal includes a signal (such as information) on at least one of the respiratory rate and heartbeat rate of the user. For example, the biological signal may include a signal (such as information) on at least one of motions of the arms, torso, and feet of the user. For example, the biological signal may include a signal (such as information) on the rolling over of the user. 
     The biological signal is detected by a detection unit  60 , for example. As will be described later, a sensor  62  is used as the detection unit  60 . In the example illustrated in  FIG.  1   , the sensor  62  is placed on the section  71 . For example, the sensor  62  is provided between the section  71  and the mattress. For example, a detection result detected by the detection unit  60  is supplied to an acquisition unit  43  (an I/O port, for example). The detection result is supplied from the acquisition unit  43  to the control unit  42 . 
     An example of the automatic control by the control unit  42  will be described later. First, an example of the manual control is described below. 
       FIGS.  2 A to  2 F  are schematic diagrams illustrating control over the motorized furniture according to the first embodiment. 
     In the example of  FIGS.  2 A to  2 F , the back section  70   a , the upper leg section  70   b , the lower leg section  70   c , and the height change section  70   h  are arranged. As illustrated in  FIG.  2 A , the inclination (angle) of the back section  70   a  is changed by operations on the control device  160  (the manipulation reception unit  20 , for example) by the user or the like. For example, a “back raising motion” or a “back dropping motion” is performed. The inclination of the section  71  (the back section  70   a , for example) is inclination in relation to the frame  75  of the bed. The inclination of the section  71  (the back section  70   a , for example) may be an angle relative to the floor surface. 
     For example, assume that the angle between the back section  70   a  and the frame  75  is a section angle θ. The section angle θ is changed by operating the control device  160 . In the example illustrated in  FIG.  2 B , the section angle θ is a second angle θ 2 . The second angle θ 2  is equal to or larger than 3 degrees and equal to or smaller than 10 degrees, for example. In the example illustrated in  FIG.  2 C , the section angle θ is a first angle θ 1 . The first angle θ 1  is substantially 0 degree (smaller than 3 degrees, for example). 
     As illustrated in  FIG.  2 D , the angles of the upper leg section  70   b  and the lower leg section  70   c  may be changed by operations on the manipulation reception unit  20 . A “knee raising motion” or a “knee dropping motion” is performed. As illustrated in  FIG.  2 D , the head section  70   d  may incline in a reverse direction so as to be located below the back section  70   a.    
     As illustrated in  FIG.  2 E , the angles of the back section  70   a , the upper leg section  70   b , and the lower leg section  70   c  may be changed in conjunction with each other by operations on the manipulation reception unit  20 . 
     As illustrated in  FIG.  2 F , the motion of the height change section  70   h  is controlled by operations on the manipulation reception unit  20 . Thereby, the height adjustment is performed. Specifically, a height H 1  of the bed surface is changed. The angle of the section  71  and the height H 1  may be changed at the same time. 
     As illustrated in  FIGS.  2 A to  2 F , a driving unit  72  (such as an actuator) is provided in the motorized furniture  310 . The movable unit  70  is moved by the operation of the driving unit  72 . 
     In one example, the driving unit  72  may include a load sensor (such as a load cell). The biological signal of the user of the motorized furniture  310  may be detected by a load applied on the load sensor (the driving unit  72 ). This corresponds to a case where the driving unit  72  that drives the movable unit  70  is provided with the detection unit  60 . In this way, the detection unit  60  may be included in the driving unit  72 . 
     Hereinbelow, a description is given of a case where the detection unit  60  includes the sensor  62 . The sensor  62  is provided separately from the driving unit  72 . 
     Hereinbelow, a functional block example of the motorized furniture  310  is described. 
       FIG.  3    is a block diagram illustrating the motorized furniture according to the first embodiment. 
     As illustrated in  FIG.  3   , the motorized furniture  310  is provided with the control unit  42 , the acquisition unit  43 , the detection unit  60 , the driving unit  72 , the movable unit  70  (the controlled unit  70 C), and the control device  160 , for example. In this example, the detection unit  60  is included in the motorized furniture  310 . In the embodiment, the detection unit  60  may be provided separately from the motorized furniture  310 . 
     The control device  160  that includes the manipulation reception unit  20  is connected to the control unit  42 . The control unit  42  is connected to the driving unit  72 . Based on a signal SM that is output in response to operations the manipulation reception unit  20  has received, a control signal SC is supplied from the control unit  42  to the driving unit  72 . The driving unit  72  drives the movable unit  70  upon receipt of the control signal SC, whereby the movable unit  70  moves. As has been described, when the driving unit  72  (such as an actuator) includes a load sensor, at least a part of the driving unit  72  may be regarded as the detection unit  60 . 
     In the embodiment, a storage unit  48  may be provided. The storage unit  48  may store therein various kinds of user state information and movable unit information. The user state information is information on user&#39;s state. The movable unit information is information on movable unit&#39;s state. The movable unit information is associated with the user state information. The control unit  42  may perform processing while retrieving information stored in the storage unit  48  as needed. For example, a part of the operation of the movable unit  70  may be prohibited for some users. For example, the operation range (such as the angle range) of the movable unit  70  may be restricted. The user state information includes such a prohibited matter or restricted matter. The movable unit information includes information on the movable unit  70 &#39;s operation state associated with this user state information. 
     Meanwhile, the detection unit  60  is configured to detect the user&#39;s state. A signal SS (detection signal) corresponding to the biological signal detected and acquired by the detection unit  60  is supplied to the acquisition unit  43 . The acquisition unit  43  is an I/O port, for example. The acquisition unit  43  is an interface of the signal SS, for example. 
     The signal SS acquired by the acquisition unit  43  is supplied to the control unit  42 . The control unit  42  is a processor, for example. An electronic circuit (such as a computer) may be used as the control unit  42 , for example. The control unit  42  is configured to control the movable unit  70  based on the signal SS corresponding to the biological signal. 
     The block diagram illustrated in  FIG.  3    illustrates functional blocks. Multiple functions may be implemented by one part (such as a circuit). For example, at least a part of the function of the control unit  42  may be implemented by the detection unit  60 . The acquisition unit  43  may be regarded as a part of the control unit  42 . 
     Hereinbelow, a description is given of an example of control based on the biological signal. In the embodiment, the biological signal includes at least one of the respiratory rate and heartbeat rate of the user, for example. The respiratory rate is the number of breaths per unit time. The heartbeat rate is the number of heartbeats per unit time. The unit time is one minute, for example. These biological signals are associated with human&#39;s (user&#39;s) state. 
     Further, the biological signal varies with time according to the human&#39;s state. For example, during waking hours, the biological signal is likely to vary with human activities. For example, during sleep, the variation of the biological signal (such as the respiratory rate and the heartbeat rate) is smaller than that of the biological signal during waking hours. For example, during sleep, the variation of at least one of motions of the arms, torso, and feet of the user is smaller than during waking hours. 
     During sleep, the biological signal also varies with a sleep state. As one example, REM sleep and non-REM sleep occur during human sleep. During REM sleep, a low-amplitude brain wave similar to that during waking hours occurs. REM sleep is accompanied with rapid eye movement. During non-REM sleep, a spindle wave or a high-amplitude δ wave occurs in a brain wave. For example, a variation of the biological signal during REM sleep is larger than a variation of the biological signal during non-REM sleep. 
     More comfortable sleep can be assumed to be provided by establishing a state where REM sleep and non-REM sleep occur properly, for example. 
     In the embodiment, the motorized furniture  310  is provided with the acquisition unit  43  and the control unit  42 . The acquisition unit  43  is configured to acquire the signal SS (detection signal) corresponding to the biological signal of the user of the motorized furniture  310  that includes the movable section  71 . For example, the signal SS corresponding to the biological signal includes information on at least one of the respiratory rate and heartbeat rate of the user. The signal SS may include information on the motion of at least one of the arms, torso, and feet of the user. The signal SS may include information on the rolling over of the user. The signal SS may include a signal on the number of the rolling over of the user. 
     The control unit  42  is configured to control the controlled unit  70 C (such as the movable unit  70 ) according to a variation of this signal SS. The control unit  42  supplies the control signal SC to the driving unit  72  based on the variation of the signal SS. Thereby, the operation of the section  71  is controlled according to the variation of the signal SS. Specifically, according to the variation of the signal SS, the control unit  42  controls the section  71  (e.g. the inclination of the section  71 ), for example. The angle of the section  71  is the section angle θ illustrated in  FIG.  2 A , for example. For example, the control unit  42  increases or decreases the inclination of the section  71  (the section angle θ) according to the variation of the signal SS. As a result, the motorized furniture  310  is automatically driven according to the user&#39;s sleep state. 
     Hereinbelow, a description is given of an example of changing the section angle θ according to the variation of the signal SS. 
       FIGS.  4 A and  4 B  are schematic diagrams illustrating operations of the motorized furniture according to the first embodiment. 
     The horizontal axis of these drawings is time tm. 
     The longitudinal axis of  FIG.  4 A  indicates a variation ΔS of the signal SS. In the longitudinal axis of  FIG.  4 A , a variation ΔS 1  is larger than a variation ΔS 2 . The variation ΔS includes at least one of a temporal change in the signal SS and a change in the amplitude of the signal SS. For example, the variation ΔS observed when a period between the minimum value and the maximum value of the signal SS is short is larger than the variation ΔS observed when the period between the minimum value and the maximum value of the signal SS is long. For example, the variation ΔS observed when the difference (amplitude) between the minimum value and the maximum value of the signal SS is large is larger than the variation ΔS observed when the difference (amplitude) between the minimum value and the maximum value of the signal SS is small. 
     The longitudinal axis of  FIG.  4 B  is an angle (the section angle θ). For example, a back raising angle changes according to the section angle θ. For example, the first angle θ 1  is substantially 0 degree. At this time, the upper surface of the section  71  ( bed ) is flat. The second angle θ 2  is equal to or larger than 3 degrees and equal to or smaller than 10 degrees, for example. At this time, the upper surface of the section  71  ( bed ) slightly inclines. For example, a third angle θ 3  of the section angle θ is larger than the second angle θ 2 . The third angle θ 3  is larger than 10 degrees, for example. 
     When the section angle θ is equal to or larger than 3 degrees and smaller than 12 degrees, it has a curative effect against orthostatic hypotension, for example. Experimental result shows that, when the section angle θ is 20 degrees, sleep becomes significantly uncomfortable as compared with when the section angle θ is 10 degrees, for example. 
     For example, it is assumed that the user can roll over easily when the upper surface of the section  71  ( bed ) is flat (the first angle θ 1 , for example). On the other hand, the user can fall asleep easily when the section  71  (the back section  70   a ) inclines gently (the second angle θ 2 , for example). Further, when the user is awake, the user often finds it natural that the inclination of the section  71  (the back section  70   a ) is large (the third angle θ 3 , for example). 
     In the embodiment, the angle of the section  71  (the section angle θ, for example) is changed according to the variation ΔS of the signal SS that corresponds to the biological signal. 
     For example, the control unit  42  performs a first operation OP 1 . The first operation OP 1  is an operation performed when the variation ΔS of the signal SS decreases. In the first operation OP 1 , the control unit  42  increases the inclination of the section  71  (the section angle θ, for example) when the variation ΔS of the signal SS decreases. For example, in the first operation OP 1 , the control unit  42  increases the section angle θ from the first angle θ 1  to the second angle θ 2 . For example, the control unit  42  increases the section angle θ when the variation ΔS of the signal SS tends to decrease after the peak (maximum) of the variation ΔS is over. 
     For example, the user&#39;s sleep is becoming deeper when the variation ΔS of the signal SS decreases. By increasing the section angle θ from the first angle θ 1  to the second angle θ 2  at this stage, it is possible to help the user&#39;s deeper sleep. For example, this can make the user sleep deeply earlier. Thereby, it is possible to provide more comfortable sleep. 
     The control unit  42  may further perform a second operation OP 2 . The second operation OP 2  is an operation performed when the variation ΔS of the signal SS increases. In the second operation OP 2 , the control unit  42  decreases the inclination of the section  71  (the section angle θ, for example) when the variation ΔS of the signal SS increases. For example, in the second operation OP 2 , the control unit  42  decreases the section angle θ from the second angle θ 2  to the first angle θ 1 . For example, the control unit  42  decreases the section angle θ when the variation ΔS of the signal SS tends to increase after the section (minimum) of the variation ΔS is over. 
     When the variation ΔS of the signal SS increases, the user often tries to roll over. At this time, the control unit makes the upper surface of the bed flat by decreasing the section angle θ to the first angle θ 1 . This helps the user roll over more easily and reduces the user&#39;s burden. Thereby, it is possible to provide more comfortable sleep. 
     Further, the control unit performs the first operation OP 1  after the second operation OP 2 . This can help the user sleep deeply earlier after he/she rolls over, for example. The control unit iterates these first operation OP 1  and second operation OP 2 . Thereby, it is possible to provide high-quality sleep. 
     In this way, in the first operation OP 1 , the control unit  42  changes the angle (the section angle θ) from the first angle θ 1  to the second angle θ 2 . The first angle θ 1  is an angle observed when the variation ΔS of the signal SS is in a first state. The second angle θ 2  is an angle observed when the variation ΔS of the signal SS is in a second state. The second state comes after the first state, and the variation ΔS in the second state is smaller than the variation ΔS in the first state. 
     Further, in the second operation OP 2 , the control unit  42  changes the angle (the section angle θ) to an angle smaller than the second angle θ 2  (the first angle θ 1 , for example) in a third state. The third state comes after the second state, and the variation ΔS in the third state is larger than the variation ΔS in the second state. 
     For example, the signal SS includes multiple states (e.g. a first signal state st 1  and a second signal state st 2 : see  FIG.  4 A ). As illustrated in  FIG.  4 A , the variation ΔS of the signal SS in the second signal state st 2  is smaller than the variation ΔS of the signal SS in the first signal state st 1 . 
     For example, the first signal state st 1  is assumed to correspond to REM sleep. For example, the second signal state st 2  is assumed to correspond to non-REM sleep. 
     For example, the first operation OP 1  corresponds to the operation observed when the first signal state st 1  transitions to the second signal state st 2 . The first operation OP 1  corresponds to the operation observed when REM sleep transitions to non-REM sleep. The second operation OP 2  corresponds to the operation observed when the second signal state st 2  transitions to the first signal state st 1 . The second operation OP 2  corresponds to the operation observed when non-REM sleep transitions to REM sleep. 
     The control unit  42  may further perform a third operation OP 3  in addition to these first operation OP 1  and second operation OP 2 . The third operation OP 3  is an operation performed when the user gets up at predetermined time t 1  (see  FIG.  4 A ). 
     As described above, the signal SS includes the first signal state st 1  and the second signal state st 2 . The control unit  42  performs the third operation OP 3  when the signal SS becomes the first signal state st 1  at the time before and closest to the predetermined time t 1 . In the third operation OP 3 , the control unit sets the inclination of the section  71  (the section angle θ) larger than the inclination increased as described above (the second angle θ 2 ), for example. The third operation OP 3  helps the user wake up, for example. In the third operation OP 3 , the section angle θ may be changed to the third angle θ 3  by way of the state of the second angle θ 2 . 
     Thereby, the user can wake up comfortably. For example, when the user is in REM sleep at the time closest to the predetermined time t 1 , an increase of the section angle θ can wake the user up. 
     In the third operation OP 3 , the section  71  may be inclined (the section angle θ) at a reverse angle (negative angle: a broken line in  FIG.  4 B ) according to the state (or taste) of the user (see the head section  70   d  in  FIG.  2 D ). In this case, the head part of the user inclines below the torso. The angle in the third operation OP 3  may be changed according to the state (such as the age, health conditions, and taste) of the user. 
     As illustrated in  FIG.  4 B , the control unit  42  may perform a falling asleep operation OPs. For example, at time ts, the user or the like makes an input indicating that the user wishes to fall asleep by manipulating the control device  160 . In this example, the section angle θ is large (the third angle θ 3 , for example) in a state before the time ts. In the state before the time ts, the section angle θ may be set at any value and may be 0 degree, for example. When the falling asleep manipulation is made at the time ts, the control unit  42  sets the section angle θ at the second angle θ 2 . This helps the user fall asleep. Then, when the variation ΔS of the signal SS corresponding to the biological signal becomes smaller, for example, the control unit  42  may decrease the section angle θ to the first angle θ 1 . Alternatively, when the variation ΔS of the signal SS corresponding to the biological signal increases again after the decrease, the control unit  42  may increase the section angle θ to the second angle θ 2 . This operation corresponds to the first operation OP 1 . 
     In the embodiment, for example, the control unit  42  may change the angle (the angle according to the variation ΔS of the signal SS) in the first operation OP 1  or the second operation OP 2  based on the relationship between past data on the variation ΔS of the signal SS and the angle of the section  71  (the section angle θ). For example, the section angle θ that brings comfortable sleep sometimes differs from one user to another. In addition, the section angle θ that brings comfortable sleep to each user sometimes differs between an initial period and later period of sleep. In this case, for example, the control unit may change the section angle θ to be set based on the relationship between the past data on the variation ΔS of the signal SS and the angle of the section  71  (the section angle θ). In other words, the control unit may set more appropriate section angle θ by learning the relationship between the past data on the variation ΔS of the signal SS and the section angle θ. For example, by learning, the control unit may customize and change the inclination (such as the angle) of at least one of the multiple factors included in the section  71  taken in at least one of the states where the user is falling asleep and where the user is already asleep. 
     In the above example, the angle that is changed according to the variation ΔS of the signal SS corresponding to the biological signal is the angle of the back section  70   a . In the embodiment, the angle of another portion included in the section  71  may be controlled according to the variation ΔS of the signal SS corresponding to the biological signal. 
     The motorized furniture  310  (see  FIG.  1   ) according to this embodiment includes the control unit  42  capable of the above operations. The control unit  42  may include the above acquisition unit  43 , or the acquisition unit  43  may be provided separately from the control unit  42 . The motorized furniture  310  includes the controlled unit  70 C (the movable unit  70 , for example). The motorized furniture  310  may further include the above detection unit  60 . An apneic state, snoring, or the like may be suppressed by the operations of the embodiment. 
     In the above example, the user&#39;s sleep state is presumed based on the biological signal, and the movable unit  70  is controlled according to the sleep state. In the embodiment, the user&#39;s posture (such as a supine position, a prone position, or a lateral position) may be presumed. The movable unit  70  may be controlled according to the presumption result of the user&#39;s posture. 
     Hereinbelow, a description is given of an example of a flowchart of the motorized furniture according to this embodiment. 
       FIG.  5    is a flowchart illustrating the operations of the motorized furniture according to the first embodiment. 
     For example, an input indicating that the user wishes to fall asleep is made by manipulating the control device  160 . Thereby, as illustrated in  FIG.  5   , the section  71  (the back section  70   a , for example) takes a small inclination (the second angle θ 2 , for example)(Step S 210 ). 
     For example, it is judged, in a predetermined period, whether or not manipulation on the control device  160  is performed (Step S 211 ). If the manipulation is performed (if “NO”), the control unit operates the section  71  according to the manipulation (Step S 217 ). For example, if a back raising manipulation input is made, the control unit performs back raising manual control. Then, the process returns back to Step S 211 . 
     In Step S 211 , if no manipulation on the control device  160  is performed (if “YES”), the control unit performs automatic control described below. 
     If no manipulation is performed (in the case of automatic control), the signal SS corresponding to the biological signal is acquired (Step S 212 ). Then, it is judged whether or not the variation ΔS of the signal SS is equal to or smaller than a threshold (Step S 213 ). If the variation ΔS of the signal SS is not equal to or smaller than the threshold, the process returns back to Step S 211 . 
     In Step S 213 , if it is judged that the variation ΔS of the signal SS is equal to or smaller than the threshold, the control unit decreases the inclination of the section  71  (the back section  70   a , for example)(Step S 214 ). For example, the control unit sets the section angle θ at the above first angle θ 1 . Steps S 213  and S 214  correspond to the falling asleep operation OPs, for example. 
     It is further judged whether or not manipulation on the control device  160  is performed (Step S 101 ). If it is judged that manipulation is performed (if “NO”), the control unit operates the section  71  according to the manipulation (Step S 102 ). Then, the process returns back to Step S 210 , for example. The process may return back to Step S 211  or Step S 101  after Step S 102 . 
     In Step S 101 , if no manipulation is performed (if “YES”), the signal SS corresponding to the biological signal is acquired (Step S 110 ). 
     It is further judged whether or not the variation ΔS of the signal SS is decreased, for example (Step S 111 ). If the variation ΔS is decreased, the control unit increases the inclination of the section  71  (the back section  70   a ) (Step S 112 ). For example, the control unit sets the section angle θ at the above second angle θ 2 . Whether or not the variation ΔS is decreased is judged using the threshold regarding the decrease of the variation ΔS, for example. Then, the process returns back to Step S 101 , for example. Step S 111  and Step S 112  correspond to the above first operation OP 1 . The first operation OP 1  helps the user sleep. 
     In Step S 111 , if the variation ΔS is not decreased, it is judged whether or not the variation ΔS is increased (Step S 121 ). Whether or not the variation ΔS is increased is judged using the threshold regarding the increase of the variation ΔS, for example. 
     In Step S 121 , if the variation ΔS is not increased, it means there is substantially no change in the variation ΔS. In this case, the process returns back to Step S 101 . 
     In Step S 121 , if the variation ΔS is increased (i.e. if in the first signal state st 1  where the variation ΔS is large), it is judged whether or not this first signal state st 1  is the first signal state st 1  at the time before and closest to the predetermined time t 1  (Step S 131 ). 
     In Step S 131 , if this first signal state is not at the time closest to the time t 1  (if “NO”), the control unit decreases the inclination of the section  71  (Step S 122 ). For example, the control unit sets the section angle θ at the first angle θ 1 . Then, the process returns back to Step S 101 , for example. Step S 121  and Step S 122  correspond to the above second operation OP 2 . The second operation OP 2  helps the user roll over more easily, for example. 
     In Step S 131 , if it is judged that this first signal state st 1  is the first signal state st 1  at the time before and closest to the time t 1 , the control unit increases the inclination of the section  71  (e.g. the control unit sets the section angle θ at the third angle θ 3 )(Step S 132 ). This helps the user wake up comfortably. 
     In the above process, some Steps may be swapped each other within a technically possible range. For example, Step S 111  and Step S 121  may be swapped each other. In this case, Step S 112  and Step S 122  are also swapped in conjunction with this. 
     Second Embodiment 
     In this embodiment, the shape of the mattress is changed based on the signal SS corresponding to the biological signal. 
       FIG.  6    is a schematic perspective view illustrating a motorized furniture according to a second embodiment of the present invention. 
     As illustrated in  FIG.  6   , a motorized furniture  320  according to this embodiment includes a mattress  76  and the control unit  42 . The motorized furniture  320  may be further provided with the acquisition unit  43 . The acquisition unit  43  may be included in the control unit  42 . The mattress  76  may be placed on the section  71  of the motorized bed. Alternatively, a surface located below the mattress  76  may be a horizontal surface. 
     For example, the mattress  76  includes multiple air cells  76   a . For example, the multiple air cells  76   a  are arranged in a direction that connects the head part of the mattress  76  with the foot part thereof (e.g. in the X-axis direction). For example, each of the multiple air cells  76   a  extends in the left-right direction of the mattress  76  (e.g. in the Y-axis direction). For example, the volume of air inside each of the multiple air cells  76   a  is controlled by a pump unit  76   b . This changes the pressure inside each of the multiple air cells  76   a . For example, this can change the height of each of the multiple air cells  76   a  (e.g. the position of the upper end of each of the multiple air cells in the Z-axis direction). 
     For example, a mattress driving unit  76   f  (e.g. an electrical circuit unit) is provided. The pump unit  76   b  is connected to the mattress driving unit  76   f  through a cable  76   c . A control unit of the mattress driving unit  76   f  operates the pump unit  76   b , thus making it possible to control the state of each of the multiple air cells  76   a  in various ways. 
     In this example, a mattress manipulation unit  76   d  is provided. The mattress manipulation unit  76   d  is connected to the mattress driving unit  76   f  through a cable  76   e . The mattress manipulation unit  76   d  is configured to receive manipulation by a person such as the user of the mattress  76 . A signal SM corresponding to the manipulation the mattress manipulation unit  76   d  has received is supplied to the mattress driving unit  76   f , thus making it possible to manually control the state of the mattress  76  (e.g. the shape of each of the multiple air cells  76   a ). 
     In this embodiment, in addition to the manual control, the state (e.g. the shape) of the mattress  76  is controlled by automatic control performed by the control unit  42 . 
     In the embodiment, the detection unit  60  (the sensor  62 , for example) is provided. The detection unit  60  is provided below the mattress  76 . The detection unit  60  is configured to detect a biological signal including the body movement of the user of the mattress  76 . The detection unit  60  outputs a signal SS corresponding to the biological signal. The acquisition unit  43  acquires this signal SS. This signal SS is supplied to the control unit  42 . In this example, the signal SS also includes information on at least one of the respiratory rate and heartbeat rate of the user. The signal SS may include information on at least one of motions of the arms, torso, and feet of the user. The signal SS may include information on the rolling over of the user. The signal SS may include a signal on the number of the rolling over of the user. 
     The control unit  42  is configured to control the state (e.g. the shape) of the mattress  76  according to the variation ΔS of the signal SS. This control is performed in such a way that the control unit controls the mattress driving unit  76   f  to control the pump unit  76   b , for example. In this manner, the control unit  42  is capable of performing the automatic control based on the biological signal in addition to the manual control. 
     Hereinbelow, firstly, an example of the state of the mattress  76  is described. 
       FIGS.  7 A and  7 B  are schematic side views illustrating the motorized furniture according to the second embodiment. 
     These drawings illustrate the state (e.g. the shape) of the mattress  76 .  FIG.  7 A  corresponds to one state (a first mattress state mt 1 ) of the mattress  76 .  FIG.  7 B  corresponds to another state (a second mattress state mt 2 ) of the mattress  76 . 
     A part of the multiple air cells  76   a  (a head part  77   a ) corresponds to the head part of the user. Another part of the multiple air cells  76   a  (a waist part  77   b ) corresponds to the waist part of the user. Still another part of the multiple air cells  76   a  (a foot part  77   c ) corresponds to the foot part of the user. 
     As illustrated in  FIG.  7 A , in the first mattress state mt 1 , the height (the height of the upper part) of the waist part  77   b  of the mattress  76  is low relative to the height (the height of the upper part) of the head part  77   a  of the mattress  76 . For example, the height of the waist part  77   b  of the mattress  76  is lower than the height of the foot part  77   c  of the mattress  76 . In the first mattress state mt 1 , the shape of the mattress  76  has a gentle inclination. When the user is laid on the mattress  76  in the first mattress state mt 1 , the back of the user becomes gently inclined. In the first mattress state mt 1 , the height of the foot part  77   c  may also be lower than the height of the head part  77   a.    
     On the other hand, as illustrated in  FIG.  7 B , in the second mattress state mt 2 , the height of the waist part  77   b  of the mattress  76  is substantially the same as the height of the head part  77   a  of the mattress  76 . The height of the waist part  77   b  of the mattress  76  is substantially the same as the height of the foot part  77   c  of the mattress  76 . In the second mattress state mt 2 , the mattress  76  is substantially flat. When the user is laid on the mattress  76  in the second mattress state mt 2 , the back of the user turns substantially flat. In the second mattress state mt 2 , the height of the waist part  77   b  may be set slightly higher than the height of the head part  77   a.    
     For example, it is assumed that the user can roll over easily when the mattress  76  is flat (e.g. in the second mattress state mt 2 ). On the other hand, the user can fall asleep easily when the mattress  76  inclines gently (e.g. in the first mattress state mt 1 ). 
     In the embodiment, the control unit  42  changes the shape of the mattress  76  based on the biological signal of the user. For example, the first mattress state mt 1  and the second mattress state mt 2  described above are switched each other. Thereby, it is possible to provide more comfortable sleep. 
       FIGS.  8 A and  8 B  are schematic diagrams illustrating operations of the motorized furniture according to the second embodiment. 
     The horizontal axis of these drawings is time tm. The longitudinal axis of  FIG.  8 A  indicates a variation ΔS of the signal SS. As illustrated in  FIG.  8 A , the signal SS includes multiple states (e.g. a first signal state st 1  and a second signal state st 2 ). In this case, the variation ΔS of the signal SS in the second signal state st 2  is also smaller than the variation ΔS of the signal SS in the first signal state st 1 . 
     The longitudinal axis of  FIG.  8 B  indicates a height HR of the waist part  77   b  of the mattress  76  relative to the height of the head part  77   a  of the mattress  76 . In the first mattress state mt 1 , the waist part  77   b  is lower than the head part  77   a , and the shape of the mattress  76  inclines gently. In the second mattress state mt 2 , the height of the waist part  77   b  is substantially the same as the height of the head part  77   a , and the shape of the mattress  76  is flat. 
     The control unit  42  performs a first operation OP 1  when the variation ΔS of the signal SS decreases. In the first operation OP 1 , the control unit decreases the height of the waist part  77   b  of the mattress  76  relative to the height of the head part  77   a  of the mattress  76 . For example, the control unit  42  decreases the height of the waist part  77   b  when the variation ΔS of the signal SS tends to decrease after the peak (maximum) of the variation ΔS is over. For example, in the first operation OP 1 , the control unit controls the mattress so that the mattress transitions from the second mattress state mt 2  to the first mattress state mt 1 . For example, in the first operation OP 1 , the control unit controls the shape of the mattress  76  so that the shape changes from a flat shape to a gently inclined shape, for example. 
     For example, the user&#39;s sleep is becoming deeper when the variation ΔS of the signal SS decreases. By controlling the shape of the mattress  76  so that the shape changes to a gently inclined shape at this stage, it is possible to help the user&#39;s deeper sleep. For example, this can make the user sleep deeply earlier. Thereby, it is possible to provide more comfortable sleep. 
     The control unit  42  may further perform a second operation OP 2 . The second operation OP 2  is an operation performed when the variation ΔS of the signal SS increases. In the second operation OP 2 , the control unit  42  sets the height of the waist part  77   b  closer to the height of the head part  77   a . For example, in the second operation OP 2 , the control unit  42  controls the mattress so that the mattress transitions from the first mattress state mt 1  to the second mattress state mt 2 . For example, in the second operation OP 2 , the control unit controls the shape of the mattress  76  so that the shape changes from a gently inclined shape to a flat shape, for example. For example, the control unit  42  decreases the height of the waist part  77   b  when the variation ΔS of the signal SS tends to increase after the section (minimum) of the variation ΔS is over. 
     When the variation ΔS of the signal SS increases, the user often tries to roll over. By controlling the shape of the mattress  76  so that the shape changes from a gently inclined shape to a flat shape at this stage, it is possible to help the user roll over more easily and reduce the user&#39;s burden. Thereby, it is possible to provide more comfortable sleep. 
     Further, the control unit performs the first operation OP 1  after the second operation OP 2 . This can help the user sleep deeply earlier after he/she rolls over, for example. The control unit iterates these first operation OP 1  and second operation OP 2 . Thereby, it is possible to provide high-quality sleep. 
     The control unit  42  may further perform a third operation OP 3  in addition to these first operation OP 1  and second operation OP 2 . The third operation OP 3  is an operation performed when the user gets up at predetermined time t 1  (see  FIG.  8 A ). 
     As has been described previously, the signal SS includes a first signal state st 1  and a second signal state st 2 . For example, the first signal state st 1  corresponds to REM sleep. The second signal state st 2  corresponds to non-REM sleep. The control unit  42  performs the third operation OP 3  when the signal SS becomes the first signal state st 1  at the time before and closest to the predetermined time t 1 . In the third operation OP 3 , the control unit  42  keeps the state where the height of the waist part  77   b  is set closer to the height of the head part  77   a  (flat state). 
     For example, REM sleep occurs at the time before and closest to the predetermined time t 1 . Then, the control unit  42  keeps the flat state of the mattress  76  even when the variation ΔS of the signal SS decreases. 
     Thereby, the user can wake up comfortably. For example, when the user is in REM sleep at the time closest to the predetermined time t 1 , the user can wake up thanks to the flat state of the mattress  76 . 
     In the third operation OP 3 , the control unit may change the shape of the mattress  76  to a reverse shape (a shape where the head part  77   a  is lower than the waist part  77   b ) according to the state (or taste) of the user. In this case, the head part of the user inclines below the torso. The shape of the mattress  76  in the third operation OP 3  may be changed according to the state (such as the age, health conditions, and taste) of the user. 
     As illustrated in  FIG.  8 B , the control unit  42  may perform a falling asleep operation OPs. For example, at time ts, the user or the like makes an input indicating that the user wishes to fall asleep by manipulating the control device  160 . For example, the mattress  76  is flat in a state before the time ts. When the falling asleep manipulation is made at the time ts, the control unit  42  sets the waist part  77   b  lower than the head part  77   a . This helps the user fall asleep. Then, the control unit  42  performs the first operation OP 1  and the second operation OP 2  described above. 
     In the embodiment, for example, the control unit  42  may change the shape of the mattress  76 , formed according to the variation ΔS of the signal SS, based on the relationship between past data on the variation ΔS of the signal SS and the shape of the mattress  76 . For example, the control unit may change the shape of the mattress  76  in the first operation OP 1  or the second operation OP 2  based on the relationship between the past data on the variation ΔS of the signal SS and the shape of the mattress  76 . For example, the shape of the mattress  76  that brings comfortable sleep sometimes differs from one user to another. In addition, the shape of the mattress  76  that brings comfortable sleep to each user sometimes differs between an initial period and later period of sleep. In this case, the control unit may change the shape of the mattress  76  to be set based on the relationship between the past data on the variation ΔS of the signal SS and the shape of the mattress  76 . In other words, the control unit may set more appropriate shape of the mattress  76  by learning the relationship between the past data on the variation ΔS of the signal SS and the shape of the mattress. 
     In the above example, the heights of multiple portions of the mattress  76 , which are located at different positions in the up-down direction thereof, are changed according to the variation ΔS of the signal SS corresponding to the biological signal. The up-down direction is a direction that connects the head part with the foot part, and corresponds to the X-axis direction of  FIG.  6   . For example, in the above example, the pressure inside the multiple portions of the mattress  76  (multiple air cells  76   a ), which are located at different positions in the up-down direction thereof, are changed according to the variation ΔS of the signal SS. 
     In the embodiment, the multiple air cells  76   a  may be arranged in the left-right direction (the Y-axis direction in  FIG.  6   ). In the embodiment, the heights of multiple portions, which are located at different positions in the left-right direction, may be changed according to the variation ΔS of the signal SS corresponding to the biological signal. In the embodiment, the pressure inside the multiple portions (multiple air cells  76   a ), which are located at different positions in the left-right direction, may be changed according to the variation ΔS of the signal SS corresponding to the biological signal. 
     The motorized furniture  320  (see  FIG.  6   ) according to this embodiment includes the control unit  42  capable of the above operations. The control unit  42  may include the above acquisition unit  43 , or the acquisition unit  43  may be provided separately from the control unit  42 . The motorized furniture  320  includes the controlled unit  70 C (the movable unit  70 , for example). The motorized furniture  320  may further include the above detection unit  60 . An apneic state, snoring, or the like may be suppressed by the operations of the embodiment. 
     In the above example, the user&#39;s sleep state is presumed based on the biological signal, and the shape of the mattress  76  is controlled according to the sleep state. In the embodiment, the user&#39;s posture (such as a supine position, a prone position, or a lateral position) may be presumed. The shape of the mattress  76  may be controlled according to the presumption result of the user&#39;s posture. 
     In the above example, the shape of the mattress  76  is controlled based on the biological signal of the user. The stiffness of the mattress  76  may be controlled based on the biological signal of the user. At least one of the shape and stiffness of a pillow may be controlled based on the biological signal of the user. For example, the user has a taste in the shape or stiffness of the mattress  76 . At least one of the shape and stiffness of the mattress  76  may be controlled according to this taste. For example, the user has a taste in the shape or stiffness of a pillow. At least one of the shape and stiffness of the pillow may be controlled according to this taste. 
     Hereinbelow, a description is given of an example of a flowchart of the motorized furniture according to this embodiment. 
       FIG.  9    is a flowchart illustrating the operations of the motorized furniture according to the second embodiment. 
     For example, an input indicating that the user wishes to fall asleep is made by manipulating the control device  160 . Thereby, as illustrated in  FIG.  9   , the control unit decreases the height of the waist part  77   b  relative to that of the head part  77   a  (Step S 610 ). For example, the control unit sets the height of the waist part  77   b  lower than that of the head part  77   a.    
     Then, Steps S 211  and S 212  and Step S 217  are executed. These steps are the same as steps described in relation to  FIG.  5   . 
     As illustrated in  FIG.  9   , it is judged whether or not the variation ΔS of the signal SS is equal to or smaller than a threshold (Step S 213 ). If the variation ΔS of the signal SS is not equal to or smaller than the threshold, the process returns back to Step S 211 . 
     In Step S 213 , if it is judged that the variation ΔS is equal to or smaller than the threshold, the control unit sets the height of the waist part  77   b  closer to the height of the head part  77   a  (Step S 614 ). For example, the control unit makes the mattress  76  substantially flat. Steps S 213  and S 614  described above correspond to the above falling asleep operation OPs, for example. 
     Then, Step S 101  and Step S 102  are executed. These steps are the same as steps described in relation to  FIG.  5   . 
     As illustrated in  FIG.  9   , the signal SS corresponding to the biological signal is acquired (Step S 110 ). It is further judged whether or not the variation ΔS of the signal SS is decreased, for example (Step S 111 ). 
     If the variation ΔS is decreased, the control unit decreases the height of the waist part  77   b  relative to that of the head part  77   a  (Step S 512 ). For example, the mattress  76  turns substantially flat. Then, the process returns back to Step S 101 , for example. Step S 111  and Step S 512  correspond to the above first operation OP 1 . The first operation OP 1  helps the user sleep. 
     In Step S 111 , if the variation ΔS is not decreased, it is judged whether or not the variation ΔS is increased (Step S 121 ). Whether or not the variation ΔS is increased is judged using the threshold regarding the increase of the variation ΔS, for example. 
     In Step S 121 , if the variation ΔS is not increased, it means there is substantially no change in the variation ΔS. In this case, the process returns back to Step S 101 . 
     In Step S 121 , if the variation ΔS is increased (i.e. if in the first signal state st 1  where the variation ΔS is large), it is judged whether or not this first signal state st 1  is the first signal state st 1  at the time before and closest to the predetermined time t 1  (Step S 131 ). 
     In Step S 131 , if this first signal state is not at the time closest to the time t 1  (if “NO”), the control unit sets the height of the waist part  77   b  closer to the height of the head part  77   a  (Step S 522 ). For example, the control unit makes the mattress  76  substantially flat. Then, the process returns back to Step S 101 , for example. Step S 131  and Step S 522  correspond to the above second operation OP 2 . The second operation OP 2  helps the user roll over more easily, for example. 
     In Step S 131 , if it is judged that this first signal state st 1  is the first signal state st 1  at the time before and closest to the time t 1 , the control unit changes at least one of the height of the waist part  77   b  and the height of the head part  77   a  (Step S 532 ). For example, the control unit makes the mattress  76  substantially flat. Alternatively, the control unit changes the shape of the mattress  76  to a reverse shape. 
     This helps the user wake up comfortably. 
     In this embodiment, some Steps may also be swapped each other within a technically possible range. For example, Step S 111  and Step S 121  may be swapped each other. In this case, Step S 512  and Step S 522  are also swapped in conjunction with this. 
     Third Embodiment 
     In this embodiment, the temperature of the motorized furniture is controlled based on the signal SS corresponding to the biological signal. For example, as has been described in relation to  FIG.  1   , the temperature control unit  73   b  (such as a heater) is sometimes provided as the controlled unit  70 C. The temperature control unit  73   b  is provided at a position corresponding to the foot part of the user, for example. Hereinbelow, a description is given of an example of changing the temperature of the temperature control unit  73   b  based on the signal SS corresponding to the biological signal. 
       FIGS.  10 A and  10 B  are schematic diagrams illustrating operations of the motorized furniture according to the third embodiment of the present invention. 
     The horizontal axis of these drawings is the time tm. The longitudinal axis of  FIG.  10 A  indicates the variation ΔS of the signal SS. In this case, the signal SS also includes multiple states (e.g. a first signal state st 1  and a second signal state st 2 ). In this case, the variation ΔS of the signal SS in the second signal state st 2  is also smaller than the variation ΔS of the signal SS in the first signal state st 1 . 
     The longitudinal axis of  FIG.  10 B  is temperature Tm of the motorized furniture  320 . In this example, the temperature Tm is the temperature of the temperature control unit  73   b . The control unit  42  is configured to control the temperature Tm of the motorized furniture  320  according to the variation ΔS of the signal SS. The control unit  42  performs a first operation OP 1 . The first operation OP 1  is an operation performed when the variation ΔS of the signal SS decreases. In the first operation OP 1 , the control unit  42  decreases the temperature Tm when the variation ΔS of the signal SS decreases. 
     For example, the temperature of the user observed when the user is sleeping is lower than the temperature of the user observed when the user is awake. By controlling the temperature of the motorized furniture according to the state of the user, it is possible to provide the user with more comfortable sleep. 
     The control unit  42  may further perform a second operation OP 2 . The second operation OP 2  is an operation performed when sleep is becoming gradually shallower. For example, during one sleep period, a sleep state in a sleep start period and a sleep state in a period near the end of sleep sometimes differ from each other. For example, in the start period, the difference between the first signal state st 1  (e.g. corresponding to REM sleep) and the second signal state st 2  (e.g. corresponding to non-REM sleep) is assumed to be large. For example, in the period near the end, the difference between the first signal state st 1  and the second signal state st 2  is assumed to be smaller than the difference in the start period. For example, it is possible to presume a sleep state based on a change in the difference between the first signal state st 1  and the second signal state st 2 . 
     For example, the control unit performs the second operation OP 2  when the difference between the first signal state st 1  and the second signal state st 2  is smaller than a certain value (threshold). In the second operation OP 2 , for example, the control unit increases the temperature Tm of the motorized furniture  320  (the temperature control unit  73   b , for example). Thereby, it is possible to provide the user with more comfortable sleep. 
     Besides, when the controlled unit  70 C includes the lighting unit  73   a  (see  FIG.  1   ), the control unit  42  may change the operation state (e.g. at least one of the lightness and color) of the lighting unit  73   a  based on the variation ΔS of the signal SS corresponding to the biological signal. 
     The control unit may control at least one of the lightness and color of a display unit (or a light) of the control device  160  based on the biological signal of the user. For example, the control unit may perform control such that the motorized furniture  310  emits a scent that helps the user sleep or wake up based on the biological signal of the user. 
     In the third embodiment, the signal SS also includes information on at least one of the respiratory rate and heartbeat rate of the user. The signal SS may include information on at least one of motions of the arms, torso, and feet of the user. The signal SS may include information on the rolling over of the user. The signal SS may include a signal on the number of the rolling over of the user. 
     Hereinbelow, some examples of the sensor  62  are described. 
       FIGS.  11 A and  11 B  are schematic diagrams illustrating the motorized furniture according to the embodiments.  FIG.  11 A  is a schematic perspective view illustrating the sensor  62  and the layout of the sensor  62 .  FIG.  11 B  is a schematic plan view illustrating the sensor  62 . In  FIG.  11 A , constituents are drawn separately from each other for making the drawing easy to read and understand. 
     As illustrated in  FIG.  11 A , in a motorized furniture  340 , the section  71  is provided on a bed leg part  74  of a bed part  70 B. The mattress  76  is provided on the section  71 . A user  81  lies on the mattress  76 . The sensor  62  (the detection unit  60 ) is provided between the section  71  and the mattress  76 , for example. In this example, the sensor  62  is in the shape of a sheet or plate. 
     As illustrated in  FIG.  11 B , the sensor  62  includes a circuit unit  62   a  and a sensor unit  62   b . The circuit unit  62   a  includes a communication unit  62   c . The communication unit  62   c  is configured to transmit and receive data to and from the control unit  42 . They transmit and receive data by any method including at least one of wired and wireless communications. 
     The sensor unit  62   b  includes a sensor device  62   d , for example. The sensor unit  62   b  is configured to detect a force (or characteristics corresponding to the force) received at the sensor unit  62   b . The force includes at least one of pressure and sound wave, for example. The sensor unit  62   b  includes a pressure sensor, for example. The sensor unit  62   b  includes a microphone, for example. 
     The force (at least one of pressure and sound wave) charged by the user  81  is applied on the sensor unit  62   b  through the mattress  76 . For example, a signal based on the force detected by the sensor unit  62   b  is output from the circuit unit  62   a . The signal thus output is supplied to the control unit  42 . The control unit  42  presumes the state of the user  81  (such as a state where the user is away from the bed, the user is sleeping, or the user wakes up) based on at least one of the magnitude of the signal (force) and a temporal change in the magnitude of the signal (force). Alternatively, the circuit unit  62   a  may presume the state of the user  81  (such as a state where the user is away from the bed, the user is sleeping, or the user wakes up) based on at least one of the force detected by the sensor  62   b  and a temporal change in the force. The state of the user  81  may include a state where the user gets up, the user is preparing for getting out of the bed (e.g. the user is in a sitting position with his/her soles of feet on the floor), the user is away from the bed, the user is falling asleep, the user is sleeping, or the user wakes up. 
     Further, at least one of the control unit  42  and the circuit unit  62   a  detects the biological signal of the user  81  based on at least one of the magnitude of the signal (force) and a temporal change in the magnitude of the signal (force). The biological signal includes at least one of the respiratory rate and heartbeat rate of the user. A sleep state may be presumed based on the biological signal. The posture of the user  81  during sleep may be presumed based on the biological signal. 
     For example, vibrations according to the state of the user  81  are applied on the sensor unit  62   b . The vibrations correspond to the body movement of the user  81 , for example. The sensor unit  62   b  detects the vibrations. The vibrations may include sound. 
     For example, vibration detection means (the sensor unit  62   b ) and a processing unit (at least a part of at least one of the circuit unit  62   a  and the control unit  42 ) are arranged. The processing unit includes a computer, for example. The vibration detection means is configured to detect vibrations of a sleeper (the user  81 ) on bedding (the bed part  70 B), for example. The processing unit includes amount of activity calculation means, sleep judgment value calculation means, and sleep state judgment means. These means are functionally separated from each other. The amount of activity calculation means is configured to calculate the amount of activity of the sleeper per sampling unit time based on the vibrations detected by the vibration detection means. For example, the sleep judgment value calculation means is configured to calculate, as a sleep judgment value, the total sum of values that are obtained by respectively multiplying the amount of activity at first time (e.g. the current time) and the amount of activity calculated at second time (e.g. the time prior to the current time) by their modification coefficients each obtained by weighting according to the corresponding time. For example, the sleep state judgment means is configured to judge that the user is awake if the sleep judgment value exceeds a predetermined threshold, and judge that the user is sleeping if the sleep judgment value is equal to or smaller than the predetermined threshold. 
       FIGS.  12 A to  12 D  are schematic diagrams illustrating another motorized furniture according to the embodiments. 
       FIG.  12 A  is a sectional view of an example of the sensor  62 .  FIG.  12 B  is a plan view of the example of the sensor  62 .  FIG.  12 C  is a perspective view illustrating the layout of the sensor  62 .  FIG.  12 D  is a side view illustrating the layout of the sensor  62 . 
     As illustrated in  FIG.  12 A , in this example, the sensor  62  includes a first platy body  62   p  and a second platy body  62   q . The second platy body  62   q  is opposed to the first platy body  62   p . These platy bodies may be sheet shaped. 
     The second platy body  62   q  includes support protrusions  62   s . The support protrusions  62   s  are opposed to an outer edge part of the first platy body  62   q . The first platy body  62   p  includes an inner part located inside the outer edge part. An air housing body  62   r  is provided between the inner part and the second platy body  62   q . In this example, a groove  62   t  is provided in the second platy body  62   q . The air housing body  62   r  is provided in the space formed by (the space divided by) the groove  62   t . One end of a signal line  62   u  is connected to the air housing body  62   r . The other end of the signal line  62   u  is connected to a detection circuit  62   v  (detection device). 
     As illustrated in  FIG.  12 B , the support protrusions  62   s  are opposed to a part of the outer edge of the first platy body  62   p . In this example, the support protrusions  62   s  are arranged at four corner parts of the first platy body  62   p . The sensor  62  is in the shape of a sheet or plate. 
     As illustrated in  FIG.  12 C , the above sensor  62  is placed on the section  71 . As illustrated in  FIG.  12 D , the sensor  62  is placed on the section  71 , and the mattress  76  is placed on the sensor. The user  81  lies on the mattress  76 . 
     For example, a force corresponding to the body movement of the user  81  is applied on the air housing body  62   r . This force includes vibrations, for example. The force (or the characteristics corresponding to the force) applied on the air housing body  62   r  is detected by the detection circuit  62   v . For example, the air housing body  62   r  is provided with a pressure detector, and a signal (detection result) acquired by the pressure detector is supplied to the detection circuit  62   v . For example, the air housing body  62   r  is provided with a microphone, and a signal (detection result) acquired by the microphone is supplied to the detection circuit  62   v . For example, an output (signal) from the detection circuit  62   v  is supplied to the control unit  42 . The control unit  42  presumes the state of the user  81  (such as a state where the user is away from the bed, the user is sleeping, or the user wakes up). Alternatively, the detection circuit  62   v  may presume the state of the user  81  (such as a state where the user is away from the bed, the user is sleeping, or the user wakes up) based on at least one of the detected force and a temporal change in the force. The state of the user  81  may include a state where the user gets up, the user is in a sitting position with his/her soles of feet on the floor (e.g. the user is preparing for getting out of the bed), the user is away from the bed, the user is falling asleep, the user is sleeping, or the user wakes up. 
     The sensor  62  is a biological information collection device, for example. In the sensor  62 , the first platy body  62   p  is disposed on the side close to the body of the user  81 , for example. The second platy body  62   q  is provided on the support side, for example. The deformable air housing body  62   r  for detecting the air pressure is provided between central parts of the first platy body  62   p  and the second platy body  62   q . The groove  62   t  for mounting the air housing body  62   r  therein is provided in the central part of the second platy body  62   q . The support protrusions  62   s  protrude in the direction from the second platy body  62   q  toward the first platy body  62   p . The support protrusions  62   s  support the circumferential four corners of the first platy body  62   p . The support protrusions  62   s  constantly support the first platy body  62   p  to keep it in a horizontal state (normal state), for example. 
     In the embodiments, various modifications of the sensor  62  are possible. 
     In the embodiments, the control unit  42  may control, as the controlled unit  70 C, at least one of the lighting unit  73   a  and the temperature control unit  73   b  (see  FIG.  1   ) based on the state of the user  81  detected by the detection unit  60 . 
     For example, the control unit may change the lightness (e.g. including on/off) of the lighting unit  73   a  based on the state (at least one of states where the user gets up, the user is in a sitting position with his/her soles of feet on the floor (e.g. the user is preparing for getting out of the bed), the user is away from the bed, the user is falling asleep, the user is sleeping, and the user wakes up) of the user  81  detected by the sensor  62 . For example, the control unit may change the direction of light, emitted from the lighting unit  73   a , based on the state of the user  81  detected by the sensor  62 . The lighting unit  73   a  includes at least one of ceiling light, reading light, and foot light, for example. The lighting unit  73   a  includes any light of the room the user  81  is in. For example, the control unit controls the lighting unit  73   a  when the variation of the signal SS (detection signal) decreases. For example, the control unit may turn down the lighting unit  73   a  when the variation of the signal SS (detection signal) decreases. This makes it possible to provide a motorized furniture capable of facilitating ease of use, and makes it possible to provide a motorized furniture capable of offering more comfortable sleep. 
     For example, the control unit may change the temperature (e.g. including on/off) of the temperature control unit  73   b  based on the state of the user  81  detected by the sensor  62 . The temperature control unit  73   b  may control the temperature around the motorized furniture (e.g. the temperature of the room the user  81  is in), for example. This makes it possible to provide a motorized furniture capable of facilitating ease of use, and makes it possible to provide a motorized furniture capable of offering more comfortable sleep. 
       FIG.  13    is a schematic perspective view illustrating a motorized furniture according to another embodiment of the present invention. 
     As illustrated in  FIG.  13   , a motorized furniture  330  is a motorized chair. The motorized furniture  330  includes the movable unit  70 . The movable unit  70  includes a backrest part  70   p  and a seating face part  70   q . The backrest part  70   p  corresponds to a section part capable of changing its angle. The seating face part  70   q  corresponds to a height change part. The seating face part  70   q  may be capable of changing its angle. The control device  160  according to the embodiments control these parts of the movable unit  70 . In the motorized furniture  330 , the movable unit  70  also moves according to the state of the user  81 . 
     In the embodiments, in the case where the movable unit  70  is provided, a drive device of the movable unit  70  (such as a motor) is preferably provided on the foot side of the motorized furniture. This makes sound generated by the operation of the drive device less likely to reach the head part of the user  81 , and thereby makes the user more comfortable. In the embodiments, the movement speed of the movable unit  70  in the case of the automatic control may be slower than the movement speed of the movable unit  70  in the case of the manual control. This makes the user  81  less likely to feel a sense of discomfort. For example, the user  81  becomes less likely to be woken up by the movement of the movable unit  70  by the automatic control. 
     In the embodiments, the state of the user  81  may include a state where the user gets up, the user is preparing for getting out of the bed (e.g. the user is in a sitting position with his/her soles of feet on the floor), the user is away from the bed, the user is falling asleep, the user is sleeping, the user wakes up, or the user rises from the bed. 
     In  FIG.  5    and  FIG.  9   , the signal SS corresponding to the biological signal may be acquired (Step S 212 ) before the judgment on whether or not manipulation is performed (Step S 211 ). For example, the process may proceed in such a way that the signal SS is acquired periodically, and the process proceeds to and after Step S 213  according to the result in Step S 211 . 
     When the section angle θ is equal to or larger than 3 degrees and smaller than 12 degrees, it is effective in the treatment of orthostatic hypotension, for example. For example, it is reported that the back raised state makes an airway less likely to be obstructed than the horizontal supine position, and thus sleeping in the back raised state improves respiratory conditions during sleep with regard to obstructive sleep apnea syndrome. 
     For example, it is assumed that the user can roll over easily when the upper surface of the section  71  ( bed ) is flat (the first angle θ 1 , for example). On the other hand, it is assumed that, when the section  71  (the back section  70   a ) inclines gently (the second angle θ 2 , for example), the user  81  finds it easy to breathe and easy to relax since the parasympathetic nerve becomes predominant, and thereby the user  81  can fall asleep easily. 
     As described above, in the first embodiment, in the first operation OP 1 , the control unit increases the section angle θ from the first angle θ 1  to the second angle θ 2  when the variation ΔS of the signal SS decreases, for example. This makes it possible to improve the respiratory conditions of the user  81  during sleep, for example. This makes it possible to prevent the user  81  from becoming apneic and waking up during sleep, for example. Thereby, it is possible to provide more comfortable sleep. 
     In the first embodiment, the control unit performs the first operation OP 1  after the second operation OP 2 , for example. This makes it possible to prevent the user  81  from becoming apneic after he/she rolls over and waking up during sleep, for example. The control unit iterates these first operation OP 1  and second operation OP 2 . Thereby, it is possible to provide high-quality sleep. 
     As described above, in the second embodiment, the control unit controls the shape of the mattress  76  so that the shape changes to a gently inclined shape when the variation ΔS of the signal SS decreases, for example. This makes it possible to improve the respiratory conditions of the user  81  during sleep, for example. This makes it possible to prevent the user  81  from becoming apneic and waking up during sleep, for example. Thereby, it is possible to provide more comfortable sleep. 
     In the second embodiment, the control unit performs the first operation OP 1  after the second operation OP 2 , for example. This makes it possible to prevent the user  81  from becoming apneic after he/she rolls over and waking up during sleep, for example. The control unit iterates these first operation OP 1  and second operation OP 2 . Thereby, it is possible to provide high-quality sleep. 
     As has been described in the above embodiments, the inclination of the section  71  may be the section angle θ. As has been described, the inclination of the section  71  may be an inclination relative to the frame  75  of the bed, or may be an angle relative to the floor surface. For example, the inclination of the section  71  may be changed by inclining the frame  75  relative to the floor surface. The inclination of the section  71  may be an inclination including the inclination of the section  71  relative to the frame  75  and the inclination of the frame  75  relative to the floor surface. 
     In one example of the embodiments, the control unit  42  performs the first operation OP 1  when the variation ΔS of the signal SS decreases. In the first operation OP 1  or the second operation OP 2 , the control unit  42  decreases the height of the waist part  77   b  of the mattress  76  relative to the height of the head part  77   a  of the mattress  76 . As has been described, the height of each of the multiple air cells  76   a  of the mattress  76  can be changed by changing the pressure inside the corresponding one of the multiple air cells  76   a . Accordingly, this first operation OP 1  may include decreasing the difference between the pressure in the head part  77   a  and the pressure in the waist part  77   b.    
     As has been described, the signal SS corresponds to at least one of the respiratory rate, the heartbeat rate, and the body movement. The variation ΔS of the signal SS may correspond to at least one of the respiratory rate, the heartbeat rate, and the body movement. The pulse rate may be deemed as substantially the same as the heartbeat rate. 
     Hereinbelow, an example of the falling asleep operation Ops ( FIG.  4 B , for example) is described. 
     In one example, the user  81  or the like makes an input indicating that the user wishes to fall asleep by manipulating the control device  160 . The user  81  or the like includes the user  81  of the motorized furniture  310 ,  320 ,  330 , or  340  and the carer of the user, for example. For example, the control device  160  may include a reception button or the like for transition to the falling asleep judgment operation. As has been described, the control device  160  can be connected to the control unit  42  by any method such as wired or wireless communication. The control device  160  may be a “smartphone type”, for example. 
     The control device  160  may include a touch panel type input unit (such as the manipulation reception unit  20 ), for example. For example, an input area for transition to a “falling asleep mode” may be provided in a display unit of the touch panel. The user  81  “touches” this input area to transition to the falling asleep judgment operation. If “falling asleep” is judged in the falling asleep judgment operation, the control unit  42  performs the falling asleep operation Ops. In the above example, the time when an input indicating that the user wishes to fall asleep is made corresponds to the time ts (see  FIG.  4 B ). 
     In another example, the falling asleep operation Ops may start at the preset time. For example, a time switch is set. For example, specific time is set, and the control unit  42  transitions to the falling asleep judgment operation at this time without manipulation of the user  81  or the like. In this case, the control unit  42  also performs the falling asleep operation Ops if “falling asleep” is judged in the falling asleep judgment operation. In this example, the preset specific time corresponds to the time ts (see  FIG.  4 B ). The specific time is set by the user  81  or the like, for example. 
     Hereinbelow, a description is given of some examples of the “falling asleep mode” including “sleep” judgment, the falling asleep operation Ops, and the like. 
       FIG.  14    is a schematic diagram illustrating operations of the motorized furniture according to the embodiments. 
       FIG.  15    is another schematic diagram illustrating the operations of the motorized furniture according to the embodiments. 
     In  FIG.  15   , the horizontal axis is time tt. 
     As illustrated in  FIG.  14   , the control device  160  (or the control unit  42 ) has a standby state (Step ST 00 ), for example. In response to manipulation received by the manipulation reception unit  20  or by way of the time switch, the control unit  42  transitions to a falling asleep mode M 01  (Step ST 01 ). 
     When the control unit  42  transitions to the falling asleep mode M 01 , the control unit performs a falling asleep detection operation HS 0  (see  FIG.  15   ) (Step ST 10 ). In the falling asleep detection operation HS 0 , the control unit  42  detects the user  81 &#39;s sleep start. In one example, the control unit  42  acquires the signal SS from the detection unit  60  (such as the sensor  62 )(the signal corresponding to the biological signal of the user  81 ) to detect the user  81 &#39;s sleep. In another example, the control unit  42  may acquire “a signal indicating that the user  81  is sleeping” detected by the detection unit  60  (such as the sensor  62 ). For example, it is judged that the user is “sleeping” if the variation ΔS of the signal SS corresponding to the biological signal (such as the respiratory rate and heartbeat rate) is smaller than the threshold. As has been described, the variation ΔS may include at least one of a temporal change in the signal SS and a change in the amplitude of the signal SS, for example. The biological signal may include information on the body movement of the user  81 . The biological signal may include a signal on the rolling over of the user (such as information on the user&#39;s posture during sleep). The falling asleep detection operation HS 0  is, for example, a “sleep detection waiting state”. The falling asleep detection operation HS 0  corresponds to Step S 212  and Step S 213 , for example (see  FIG.  5    and  FIG.  9   ). 
     In the falling asleep detection operation HS 0 , assume that the time when it is judged that “the user  81  is sleeping” is first time t 01  (see  FIG.  15   ). As illustrated in  FIG.  15   , the control unit  42  (or the detection unit  60 ) performs a judgment operation Dc 0  to judge whether or not the user  81  is sleeping. The time when it is judged that “the user  81  is sleeping” corresponds to the first time t 01 . The first time t 01  is the time when the sleep of the user  81  of the motorized furniture is detected. 
     As illustrated in  FIG.  14   , for example, the control unit  42  measures the elapse of time since the first time t 01  (“sleep duration”). The “sleep duration” denotes a period of time in which sleep continues. If the “sleep duration” becomes equal to or larger than a first time threshold (Step ST 11 ), the control unit  42  transitions to a first falling asleep operation HS 1  (see  FIG.  15   )(Step ST 20 ). This transition time is set at second time t 02  (see  FIG.  15   ). The first time threshold is 20 minutes, for example. The first time threshold may take any value exceeding 0 minute and equal to or smaller than 120 minutes. 
     For example, as illustrated in  FIG.  15   , the control unit  42  performs a judgment operation Dc 1  at the second time t 02 . The time when it is judged that “the elapse of time Δt 12  since the first time t 01  is equal to or larger than the first time threshold” in the judgment operation Dc 1  corresponds to the second time t 02 . The second time t 02  corresponds to the time of transition from the falling asleep detection operation HS 0  to the first falling asleep operation HS 1 . 
     The first falling asleep operation HS 1  performed by the control unit  42  is the operation (e.g. monitor operation) of acquiring the signal SS corresponding to the biological signal of the user  81 , for example. 
     As illustrated in  FIG.  14   , if the variation of the biological signal satisfies a predetermined condition (first variation condition)(Step ST 21 ), the control unit  42  performs a second falling asleep operation HS 2  (see  FIG.  15   )(Step ST 25 ). 
     For example, as illustrated in  FIG.  15   , a predetermined period D 1  elapses after the second time t 02 . When the predetermined period D 1  elapses, the control unit  42  performs a judgment operation Dc 2 . The predetermined period D 1  is 60 seconds, for example. In the judgment operation Dc 2 , it is judged whether or not the variation ΔS of the signal SS corresponding to the biological signal of the user  81  in a first period p 11  during the first falling asleep operation HS 1  satisfies the first variation condition. The variation ΔS of the signal SS in the first period p 11  during the first falling asleep operation HS 1  satisfies the first variation condition if this variation ΔS satisfies at least one of conditions where the variation ΔS in the first period p 11  is smaller than the variation ΔS in a first prior period p 10  prior to the first period p 11  during the first falling asleep operation HS 1 , where the absolute value of the difference between the variation ΔS in the first period p 11  and the variation ΔS in the first prior period p 10  is smaller than a first variation threshold, and where the absolute value of the difference between the variation ΔS in the first period p 11  and the variation ΔS in a period p_M prior to this period is smaller than the first variation threshold. The control unit performs the second falling asleep operation HS 2  (see  FIG.  15   ) if the variation ΔS satisfies this first variation condition (Step ST 25  in  FIG.  14   ). In one example, the variation ΔS is a heartbeat rate. The heartbeat rate may be a heartbeat rate per minute that is calculated from an average value of the number of heartbeats (the number of peaks R represented in a waveform in an electrocardiogram) in a certain period (e.g. 5 seconds), for example. In the embodiments, the heartbeat rate may be obtained by averaging the number of heartbeats in a period between peaks (between R-R) of the waveform. 
     In one example, the length of each of the first period p 11  and the first prior period p 10  may be equal to or longer than 10 seconds and equal to or shorter than 5 minutes. 
     In the above example, in the judgment of operation (Step ST 21 ) on whether or not the variation of the biological signal satisfies the predetermined condition (first variation condition), the control unit evaluates the variation ΔS of the signal SS between the first period p 11  and the period prior to the first period p 11  during the first falling asleep operation HS 1 . As will be described later, the way of judgment using the first variation condition may be modified in various ways. As will be described later, the control unit may make judgments according to the result of evaluation of the variation ΔS of the signal SS in the first period p 11  during the first falling asleep operation HS 1 . Then, if the variation of the biological signal satisfies the predetermined condition described above (first variation condition)(Step ST 21 ), the control unit performs the second falling asleep operation HS 2 . 
     In the second falling asleep operation HS 2 , the control unit  42  performs at least one of: the operation of decreasing the inclination of the section  71  of the motorized furniture; the operation of decreasing the gap between the height of the head part  77   a  of the mattress  76  of the motorized furniture and the height of the waist part  77   b  of the mattress; and the operation of decreasing the difference between the pressure in the head part  77   a  and the pressure in the waist part  77   b  (Step ST 26  in  FIG.  14   ). 
     In Step ST 26 , the operations such as decreasing the inclination by a predetermined amount and decreasing the difference by a predetermined amount are performed. After Step ST 26  is over, the control unit stops the second falling asleep operation HS 2  (Step ST 27  in  FIG.  14   ). 
     In this manner, in the embodiments, for example, the control unit  42  performs the second falling asleep operation HS 2  if the variation ΔS satisfies the first variation condition described above in the first falling asleep operation HS 1 . In the second falling asleep operation HS 2 , the control unit  42  decreases the inclination at the user  81 &#39;s back, for example. Thereby, the user  81 &#39;s posture turns close to flat, whereby the user finds it easy to roll over. 
     As illustrated in  FIG.  14   , if the variation ΔS does not satisfy the first variation condition described above (Step ST 22 ) in the first falling asleep operation HS 1 , the process proceeds to Step ST 27  and the control unit does not perform the second falling asleep operation HS 2  (Steps ST 25  and ST 26 ). For example, the control unit  42  does not perform the second falling asleep operation HS 2  if, in the first falling asleep operation HS 1 , the absolute value (difference value) of the difference between the variations ΔS described above exceeds the first variation threshold and the variation ΔS in the first period p 11  is larger than the variation ΔS in the first prior period p 10 . 
     If the variation ΔS satisfies the first variation condition described above in the first falling asleep operation HS 1  (Step ST 21 ), the user  81 &#39;s sleep is presumed to deep, for example. On the other hand, if the variation ΔS does not satisfy the first variation condition described above in the first falling asleep operation HS 1  (e.g. Step ST 22 ), the user  81 &#39;s sleep is presumed to shallow. By performing the second falling asleep operation HS 2  described above when the user  81 &#39;s sleep is presumed to deep, it is possible to inhibit the user  81  from being woken up by the second falling asleep operation HS 2 . 
     In one example according to the embodiments, the control unit may perform the above control operation (such as the second falling asleep operation HS 2 ) when the section angle θ in the falling asleep detection operation (Step ST 10 ) is equal to or larger than 0 degree and equal to or smaller than 30 degrees. For example, if the section angle θ in the falling asleep detection operation (ST 10 ) is smaller than 0 degree (negative angle) or larger than 30 degrees, the control unit may perform no control operation (such as the second falling asleep operation HS 2 ) even when the process proceeds to the falling asleep mode M 01 . By not performing the control operation (such as the second falling asleep operation HS 2 ) when the section angle θ takes the above angle, it is possible to reduce a sense of discomfort. 
     As illustrated in  FIG.  14   , if the detected signal SS does not satisfy the predetermined condition in the first falling asleep operation HS 1  (Step ST 23 ), the control unit may continue the first falling asleep operation HS 1  (Step ST 20 ). For example, when the signal SS is the heartbeat rate, an average heartbeat rate is calculated from three successive heartbeats. For example, in Step ST 23 , the process returns back to Step ST 20  if the detected number of heartbeats is two or smaller. For example, the process may return back to Step ST 20  if the average heartbeat rate thus detected does not fall within a predetermined range. For example, the process may return back to Step ST 20  if the average heartbeat rate thus detected is smaller than 40 times/minute or larger than 100 times/minute. 
     On the other hand, for example, in Step ST 21 , the control unit transitions to the second falling asleep operation HS 2  (Step ST 25 ) if the difference between the average heartbeat rate in the first period p 11  (see  FIG.  15   ) and the average heartbeat rate in the first prior period p 10  (see  FIG.  15   ) is smaller than 5 times/minute. In this case, the first variation threshold is 5 times/minute. 
     In the embodiments, for example, the inclination angle decreased at a time is set small. For example, the difference between the angle of the section  71  (e.g. the section angle θ) after the decrease of inclination and the angle of the section  71  (the section angle θ) in the period prior to this period is 1 degree or smaller. This angle difference may be 0.6 degrees or smaller. This angle difference may be 0.3 degrees or smaller. 
     For example, during one change of the section angle θ, the change speed of the section angle θ in an “initial period” may be lower than the change speed of the section angle θ in a “later period” after this “initial period”. For example, during one change of the section angle θ, the change speed of the section angle θ in the “later period” may be higher than the change speed of the section angle θ in a “further later period”. The operation may be performed slowly at the start of the operation and the end of the operation. 
     In one example, a period of time needed from Step ST 25  to Step ST 27  is equal to or longer than 1 second and equal to or shorter than 3 seconds. 
     The control unit stops the control operation once one second falling asleep operation HS 2  (the control operation such as the decrease of inclination) is over (Step ST 27 ). When a threshold period (such as 60 seconds) elapses after this stop (Step ST 28 ), the process returns back to the first falling asleep operation HS 1  (Step ST 20 ). For example, the control unit performs the second round&#39;s first falling asleep operation HS 1  (Step ST 20 ). 
     During one cycle (Steps ST 20  to ST 27 ), the user  81 &#39;s sleep state is detected in Steps ST 21  to ST 23 . Then, when the user  81 &#39;s sleep is presumed to deep, the control unit performs the second falling asleep operation HS 2  (the control operation such as the decrease of inclination)(Steps ST 25  and ST 26 ). The degree of control (such as the degree of the decrease of inclination) in one control operation is set small. The cycle as described above is iterated. In other words, as illustrated in  FIG.  15   , the control unit may iterate the first falling asleep operation HS 1  and the second falling asleep operation HS 2 . An example of iteration of the first falling asleep operation HS 1  and the second falling asleep operation HS 2  will be described later. 
     For example, by the iteration of the above Steps ST 20  to ST 27 , the section  71  turns flat, or the mattress  76  turns flat. When the section  71  turns flat or the mattress  76  turns flat, the change of the inclination, height, or stiffness reaches its limit and becomes no longer available. In this case, the process may return back to the standby state (Step ST 00 ). 
     In the embodiments, the process may return back to the standby state (Step ST 00 ) upon receipt of manipulation for cancelling the falling asleep mode M 01  (Step ST 43 ). 
     The process may return back to the standby state (Step ST 00 ) upon receipt of manipulation for cancelling the falling asleep mode M 01  (Step ST 41 ) in the falling asleep detection operation (Step ST 10 ). The process may return back to the standby state (Step ST 00 ) upon receipt of manipulation for cancelling the falling asleep mode M 01  (Step ST 42 ) in Step ST 20 . 
     The control unit may continue the falling asleep detection operation HS 0  (Step ST 10 ) upon detection of at least one of states where the user  81  wakes up and the user is away from the bed (Step ST 31 ) in the falling asleep detection operation (Step ST 10 ). The process may return back to the falling asleep detection operation HS 0  (Step ST 10 ) upon detection of at least one of states where the user  81  wakes up and the user is away from the bed (Step ST 33 ) in Step ST 27 . The process may return back to the standby state (Step ST 00 ) upon detection of a state where the user  81  is away from the bed and upon lapse of a predetermined period in the falling asleep detection operation (Step ST 10 ). 
     As has been described, the control unit may iterate the first falling asleep operation HS 1  and the second falling asleep operation HS 2 . For example, as illustrated in  FIG.  15   , when the first round&#39;s predetermined period D 1  elapses, the control unit performs the judgment operation Dc 2  in the first round&#39;s first falling asleep operation HS 1  as described above. For example, the control unit performs the second falling asleep operation HS 2  according to the judgment operation Dc 2 , for example. Then, the control unit performs the second round&#39;s first falling asleep operation HS 1 . When the second round&#39;s predetermined period (period D 2 ) elapses, the control unit performs the judgment operation Dc 2  in the second round&#39;s first falling asleep operation HS 1 . In this judgment operation Dc 2 , the following first difference is evaluated. The first difference indicates the difference between the signal SS in a second period p 21  and the signal SS in a second prior period p 20  prior to the second period p 21 , for example. Alternatively, the first difference may be the difference between the signal SS in the second period p 21  and the signal SS in a period prior to the second period p 21  (e.g. the first period p 11 ), for example. The control unit performs the second round&#39;s judgment operation Dc 2  based on the result of the first difference. 
     The control unit performs the second round&#39;s second falling asleep operation HS 2  based on the result of the second round&#39;s judgment operation Dc 2 , then further performs the judgment operation when the third round&#39;s predetermined period (period D 3 ) elapses, and then performs the third round&#39;s first falling asleep operation HS 1 . 
     In the third round&#39;s judgment operation, the following second difference is evaluated. The second difference indicates the difference between the signal SS in a third period p 31  and the signal SS in a third prior period p 30  prior to the third period p 31  in the third round&#39;s first falling asleep operation HS 1 , for example. Alternatively, the second difference may be the difference between the signal SS in the third period p 31  in the third round&#39;s first falling asleep operation HS 1  and the signal SS in a period prior to the third period p 31  (e.g. the second period p 21 ). The second difference is evaluated, and the control unit performs the third round&#39;s judgment operation based on the result of the second difference. 
     In this way, the control unit detects the user  81 &#39;s sleep state, and performs the second falling asleep operation HS 2  (user&#39;s back control) to a slight degree when the user  81 &#39;s sleep is deep. This makes it possible to inhibit the user  81  from being woken up by the second falling asleep operation HS 2 . By iterating the above cycle, the section  71  turns flat, for example. The mattress  76  turns flat, for example. In the flat state, the user  81  can roll over easily. Then, the control unit may perform operations such as the first operation OP 1  and the second operation OP 2  described in relation to  FIG.  4 A  and  FIG.  4 B , for example. The control unit may further perform the third operation OP 3 . 
     The above Steps ST 20  to ST 27  may be performed in the second operation OP 2  (the decrease of inclination). 
     As has been described, the second angle θ 2  is equal to or larger than 3 degrees and equal to or smaller than 10 degrees, for example. The inclination of the section  71  (the section angle θ) may be set at the second angle θ 2  when the control unit transitions to the first falling asleep operation HS 1  (Step ST 20 ). The user  81  can fall asleep easily when the section  71  (the back section  70   a ) inclines gently (the second angle θ 2 , for example). 
     In another example according to the embodiments, as illustrated in  FIG.  15   , the control unit may evaluate, in the falling asleep detection operation HS 0 , the variations ΔS of the signal SS, corresponding to the biological signal of the user  81 , in two successive periods (e.g. a period p_M and a prior period p_(M−1)) between the first time t 01  and the second time t 02 . The control unit may perform the judgment operation Dc 1  or the second falling asleep operation HS 2  based on this evaluation result. In this case, the sleep of the user  81  of the motorized furniture is also detected at the first time t 01 . The control unit transitions to the first falling asleep operation HS 1  at the second time t 02  after the first time t 01 . The user  81 &#39;s sleep state at the second time t 02  satisfies at least one of first and second conditions. The first condition is that the elapse of time from the first time t 01  to the second time t 02  is equal to or larger than the first time threshold. The second condition is satisfied when the absolute value of the difference between the variations ΔS of the signal SS, corresponding to the biological signal of the user  81 , in the two successive periods (e.g. the period p_M and the prior period p_(M−1)) between the first time t 01  and the second time t 02  is smaller than a threshold (second condition threshold). 
     In this way, in another example of the embodiments, the control unit may transition from the falling asleep detection operation HS 0  to the first falling asleep operation HS 1  based on not only the elapse of time since the first time t 01  but also the degree of stability of the signal SS during the falling asleep detection operation HS 0 . 
     In this example, the control unit  42  also performs the second falling asleep operation HS 2  when the variation ΔS of the signal SS in the first period p 11  during the first falling asleep operation HS 1  satisfies the predetermined condition (signal variation condition). As illustrated in  FIG.  15   , this condition is satisfied when the variation ΔS of the signal SS in the first period p 11  is smaller than the variation ΔS in the period prior to the first period (e.g. the first prior period p 10 ) or when the absolute value of the difference between the variation ΔS in the first period p 11  and the variation ΔS in the above prior period (e.g. the period p_M) is smaller than the first variation threshold. 
     In this case, in the second falling asleep operation HS 2 , the control unit  42  also performs at least one of: the operation of decreasing the inclination of the section  71  of the motorized furniture; the operation of decreasing the gap between the height of the head part  77   a  of the mattress  76  of the motorized furniture and the height of the waist part  77   b  of the mattress; and the operation of decreasing the difference between the pressure in the head part  77   a  and the pressure in the waist part  77   b.    
     In this case, the control unit also detects the user  81 &#39;s sleep state, and performs the second falling asleep operation HS 2  (user&#39;s back control) to a slight degree when the user  81 &#39;s sleep is deep. This makes it possible to inhibit the user  81  from being woken up by the second falling asleep operation HS 2 . 
     In this example, the above prior period may be a period during the first falling asleep operation HS 1 . The above prior period may be a period between the first time t 01  and the second time t 02  (e.g. a period during the falling asleep detection operation). 
       FIG.  16    is still another schematic diagram illustrating the operations of the motorized furniture according to the embodiments. 
     In the example illustrated in  FIG.  16   , as is the case with the above, the control unit  42  performs the judgment operation Dc 1  at the second time t 02 . The control unit transitions from the falling asleep detection operation HS 0  to the first failing asleep operation HS 1  at the second time t 02 . 
     As illustrated in  FIG.  16   , the predetermined time D 1  elapses after the second time t 02 . After the predetermined time D 1  elapses, the control unit  42  performs the judgment operation Dc 2 . In this example, the signal SS in the first period p 11  is detected. If the signal SS detected in the first period p 11  satisfies the predetermined condition, the control unit  42  performs the second falling asleep operation HS 2  described above (Step ST 26  in  FIG.  14   ). In this example, in Step ST 21  of  FIG.  14   , the variation ΔS of the signal SS in the first period p 11  during the first falling asleep operation HS 1  is used as the variation of the biological signal, for example, and this variation ΔS is compared with the predetermined value (the first variation threshold). 
     For example, when the signal SS is the heartbeat rate, it is detected that the heartbeat rate in the predetermined range is calculated successively three times in the first period p 11 . Based on this result, the control unit  42  performs the second falling asleep operation HS 2 . As has been described, in the second falling asleep operation HS 2 , the control unit  42  performs at least one of: the operation of decreasing the inclination of the section  71  of the motorized furniture  310 ; the operation of decreasing the gap between the height of the head part  77   a  of the mattress  76  of the motorized furniture  320  and the height of the waist part  77   b  of the mattress; and the operation of decreasing the difference between the pressure in the head part  77   a  and the pressure in the waist part  77   b.    
     As illustrated in  FIG.  16   , after the predetermined time D 2  elapses after the judgment operation Dc 2 , the control unit  42  performs the judgment operation Dc 3 . In this example, the signal SS in the second period p 21  prior to the judgment operation Dc 3  is detected. For example, if the difference between the signal SS in the second period p 21  and the signal SS in the first period p 11  satisfies the predetermined condition, the control unit  42  performs the second round&#39;s second falling asleep operation HS 2 . 
     As illustrated in  FIG.  16   , after the predetermined time D 3  elapses after the judgment operation Dc 3 , the control unit  42  performs the second round&#39;s judgment operation Dc 3 . In this example, the signal SS in the third period p 31  prior to the second round&#39;s judgment operation Dc 3  is detected. For example, if the difference between the signal SS in the third period p 31  and the signal SS in the second period p 21  satisfies the predetermined condition, the control unit  42  performs the third round&#39;s second falling asleep operation HS 2 . 
     In this way, the judgment operation Dc 3  may be iterated multiple times after the judgment operation Dc 2 . By iterating the judgment operation Dc 3  multiple times, the inclination of the section  71  is slowly decreased little by little, for example. 
     Iterating the above judgment operation multiple times corresponds to iterating the processing from Step ST 20  to Step ST 27  in  FIG.  14    multiple times, for example. In the iteration of the processing multiple times, the “variation of the biological signal” and the “first variation threshold” in Step ST 21  may be changed, for example. In the example of  FIG.  16   , in the initial judgment, the variation ΔS of the signal SS in the first period p 11  is compared with the predetermined value. Then, in the second or later judgment, the variation ΔS between the corresponding period and the period prior to this period is compared with the predetermined value. 
     The embodiments can provide a motorized furniture capable of facilitating ease of use when the user falls asleep. 
     The reference signs in the drawings are as follows. 
       15 : cable,  20 : manipulation reception unit,  42 : control unit,  43 : acquisition unit,  48 : storage unit,  60 : detection unit,  62 : sensor,  62   a : circuit unit,  62   b : sensor unit,  62   c : communication unit,  62   d : sensor device,  62   p : first platy body,  62   q : second platy body,  62   r : air housing body,  62   s : support protrusion,  62   t : groove,  62   u : signal line,  62   v : detection circuit,  70 : movable unit,  70 B: bed part,  70 C: controlled unit,  70   a : back section,  70   b : upper leg section,  70   c : lower leg section,  70   d : head section,  70   g : caster,  70   h : height change section,  70   p : backrest part,  70   q : seating face part,  71 : section,  72 : driving unit,  73   a : lighting unit,  73   b : temperature control unit,  74 : bed leg part,  75 : frame,  76 : mattress,  76   a : air cell,  76   b : pump unit,  76   c : cable,  76   d : mattress manipulation unit,  76   e : cable,  76   f : mattress driving unit,  77   a : head part,  77   b : waist part,  77   c : foot part,  81 : user, ΔS, ΔS 1 , ΔS 2 : variation, Δt 12 : elapse of time, θ: section angle, θ 1  and θ 2 : first to third angles,  160 : control device,  310 ,  320 ,  330 ,  340 : motorized furniture, D 1 , D 2 , D 3 : time, Dc 0 , Dc 1 , Dc 2 , Dc 3 : judgment operation, H 1 , HR: height, HS 0 : falling asleep detection operation, HS 1 , HS 2 : first and second falling asleep operations, M 01 : falling asleep mode, OP 1  to OP 3 : first to third operations, Ops: falling asleep operation, SC: control signal, SM: signal, SS: signal, Tm: temperature, mt 1 , mt 2 : first and second mattress states; p_(M−1): prior period, p_M: period, p 10 , p 20 , p 30 : first to third periods, p 11 , p 21 , p 31 : first to third periods, st 1 , st 2 : first and second signal states, t 01 : first time, t 02 : second time, t 1 : time, tm: time, ts: time, tt: time. 
     The embodiments may include the following configuration (e.g. technique) ideas, for example. 
     (Configuration 1) 
     A motorized furniture including a control unit, in which 
     the control unit transitions to a first falling asleep operation at second time where the elapse of time since first time, where the sleep of a user of the motorized furniture is detected, is equal to or larger than a first time threshold, 
     the control unit performs a second falling asleep operation when a variation of a signal corresponding to a biological signal of the user in a first period during the first falling asleep operation is smaller than the variation in a first prior period, which exists prior to the first period, during the first falling asleep operation or when the absolute value of a difference between the variation in the first period and the variation in the first prior period is smaller than a first variation threshold, and 
     in the second falling asleep operation, the control unit performs at least one of: an operation of decreasing the inclination of a section of the motorized furniture; an operation of decreasing the gap between the height of a head part of a mattress of the motorized furniture and the height of a waist part of the mattress; and an operation of decreasing the difference between the pressure in the head part and the pressure in the waist part. 
     (Configuration 2) 
     A motorized furniture including a control unit, in which 
     the control unit transitions to a first falling asleep operation at second time after first time where the sleep of a user of the motorized furniture is detected, the state of the sleep of the user at the second time satisfies at least one of a first condition and a second condition, the first condition is that the elapse of time from the first time to the second time is equal to or larger than a first time threshold, the second condition is satisfied when the absolute value of a difference between variations of a signal, corresponding to a biological signal of the user, in two successive periods between the first time and the second time is smaller than a threshold of the second condition, 
     the control unit performs a second falling asleep operation when the variation in a first period during the first falling asleep operation is smaller than the variation in a period prior to the first period or when the absolute value of a difference between the variation in the first period and the variation in the prior period is smaller than a first variation threshold, and 
     in the second falling asleep operation, the control unit performs at least one of: an operation of decreasing the inclination of a section of the motorized furniture; an operation of decreasing the gap between the height of a head part of a mattress of the motorized furniture and the height of a waist part of the mattress; and an operation of decreasing the difference between the pressure in the head part and the pressure in the waist part. 
     (Configuration 3) 
     The motorized furniture described in the configuration 2, in which the prior period exists during the first falling asleep operation. 
     (Configuration 4) 
     The motorized furniture described in the configuration 2, in which the prior period exists between the first time and the second time. 
     (Configuration 5) 
     The motorized furniture described in any one of the configurations 1 to 4, in which the control unit iterates the first falling asleep operation and the second falling asleep operation. 
     (Configuration 6) 
     The motorized furniture described in any one of the configurations 1 to 5, in which 
     in the second falling asleep operation, the control unit performs the operation of decreasing the inclination of the section of the motorized furniture, and 
     the difference between the angle of the section after the decrease of inclination and the angle of the section in a period prior to the decrease of inclination is 1 degree or smaller. 
     (Configuration 7) 
     The motorized furniture described in any one of the configurations 1 to 6, in which 
     the motorized furniture further includes a manipulation reception unit that is capable of communicating with the control unit, and 
     once the manipulation reception unit receives manipulation, the control unit starts detecting the sleep of the user. 
     (Configuration 8) 
     The motorized furniture described in any one of the configurations 1 to 6, in which the control unit starts detecting the sleep of the user at preset time. 
     (Configuration 9) 
     The motorized furniture described in any one of the configurations 1 to 8, in which the control unit finishes the first falling asleep operation if at least one of states where the user wakes up and the user is away from the bed continues for a second time threshold or longer. 
     (Configuration 10) 
     The motorized furniture described in any one of the configurations 1 to 8, in which the control unit finishes the second falling asleep operation if at least one of states where the user wakes up and the user is away from the bed continues for a second time threshold or longer. 
     (Configuration 11) 
     The motorized furniture described in any one of the configurations 1 to 8, in which the control unit finishes detecting the sleep of the user if at least one of states where the user wakes up and the user is away from the bed continues for a second time threshold or longer. 
     (Configuration 12) 
     The motorized furniture described in any one of the configurations 1 to 11, in which the length of the first period is equal to or longer than 10 seconds and equal to or shorter than 5 minutes. 
     (Configuration 13) 
     The motorized furniture described in any one of the configurations 1 to 12, in which the first time threshold is equal to or longer than 5 minutes and equal to or shorter than 30 minutes. 
     (Configuration 14) 
     The motorized furniture described in any one of the configurations 1 to 13, in which the signal includes information on the heartbeat rate of the user. 
     (Configuration 15) 
     The motorized furniture described in any one of the configurations 1 to 13, in which the signal includes information on the respiratory rate of the user. 
     (Configuration 16) 
     The motorized furniture described in any one of the configurations 1 to 13, in which the signal includes information on at least one of motions of the arms, torso, and feet of the user. 
     (Configuration 17) 
     The motorized furniture described in any one of the configurations 1 to 13, in which the signal includes information on the rolling over of the user. 
     (Configuration 18) 
     The motorized furniture described in the configuration 1, in which, in the first falling asleep operation, the control unit does not perform the second falling asleep operation if the absolute value is equal to or larger than the first variation threshold. 
     (Configuration 19) 
     The motorized furniture described in the configuration 1, in which the control unit does not perform the second falling asleep operation if the variation in the first period during the first falling asleep operation is smaller than the variation in the first prior period. 
     (Configuration 20) 
     The motorized furniture described in any one of the configurations 1 to 19, in which 
     after the first falling asleep operation and the second falling asleep operation, the signal includes a first signal state and a second signal state, 
     the variation of the signal in the second signal state is smaller than the variation of the signal in the first signal state, and 
     when the signal becomes the first signal state at the time before and closest to predetermined time, the control unit sets the inclination of the section larger than the inclination increased. 
     According to the embodiments, it is possible to provide a motorized furniture capable of facilitating ease of use. 
     The embodiments of the present invention have been described above with reference to the specific examples. However, the present invention is not limited to these specific examples. For example, any specific configuration of the constituents, such as the control unit, the acquisition unit, the movable unit, the section, and the mattress, included in the motorized furniture falls within the scope of the present invention as long as such a configuration is selected appropriately by those skilled in the art within a known range and can implement the present invention in the same way as those in the specific examples and bring about the same effect as those in the specific examples. 
     Any combination of any two or more constituents of the specific examples that are combined within a technically possible range also falls within the scope of the present invention as long as such a combination includes the essence of the present invention. 
     In addition, any motorized furniture that those skilled in the art can embody by appropriately changing the design of the motorized furniture described above in the embodiments of the present invention also falls within the scope of the present invention as long as such a motorized furniture includes the essence of the present invention. 
     Besides, those skilled in the art can conceive of various change examples and modification examples within the concept of the present invention, and such change examples and modification examples are also deemed to fall within the scope of the present invention.