Patent Publication Number: US-2020289357-A1

Title: Assist apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Patent Application No. 2019-043462 filed on Mar. 11, 2019, Japanese Patent Application No. 2019-043463 filed on Mar. 11, 2019, and Japanese Patent Application No. 2019-043464 filed on Mar. 11, 2019, each incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to an assist apparatus that assists work in a state of being worn on a human body. 
     2. Description of Related Art 
     Various assist apparatuses that assist work in a state of being worn on a human body have been proposed. For example, Japanese Patent Application Publication No. 2003-265548 (JP 2003-265548 A) describes a wearable boost apparatus including a wire wind-up drum, which serves as a drive section, in a drive section fitting mechanism to be detachably fitted to the hip region of a user. A boost transmission mechanism to be detachably fitted to the upper part of the user&#39;s body is pivotally attached above the drive section fitting mechanism so as to be pivotable in a front-rear direction. A reaction force reception mechanism that operates in coordination with movement of the legs of the user is provided below the drive section fitting mechanism. A boost transmission wire is provided in a tense state between the drive section of the drive section fitting mechanism and the boost transmission mechanism and a tension transmission wire is provided in a tense state between the drive section fitting mechanism and the reaction force reception mechanism. 
     SUMMARY 
     The wearable boost apparatus described in JP 2003-265548 A enables, when the user lifts a heavy load with the wearable boost apparatus worn on the body, performing the lifting work efficiently with a small burden. Also, the wearable boost apparatus prevents a large load from being imposed on the lower back of the user and thus enables reduction of the risk of injuring the back. However, the boost transmission mechanism includes, e.g., a pair of interlocking rods for transmitting an auxiliary force to the part from the waist to the shoulders of the upper half of the body, each of the pair of interlocking rods being made of a hollow steel pipe, and a tilting rod made of a stainless steel tube, the tilting rod extending upward and being disposed between the pair of interlocking rods. Also, the reaction force reception mechanism provided on the legs includes, e.g., a pair of extendable connection rods detachably disposed on the right and left legs. 
     As stated above, in the wearable boost apparatus described in JP 2003-265548 A, the assist force transmission mechanisms include rigid body components such as various types of rods and thus are poor in capability of following movement of the wearer and are very heavy, causing difficulty in reducing the operator&#39;s burden. Also, because of including rigid body components such as various types of rods, the assist force transmission mechanisms have difficulty in responding to variations in physical size of wearers. In addition, positions of, e.g., each of joints in the wearable boost apparatus are easily displaced from ideal positions for the wearer, which may cause discomfort in wearing, and in addition, may cause a decrease in assist force transmission efficiency. Furthermore, when the wearer travels to a work site at which the wearer performs the work of, e.g., lifting and lowering packages, on foot, if no assist force is generated, the wearer cannot easily walk because of resistance of the actuator being imposed. 
     The present disclosure provides an assist apparatus that is light, properly absorbs a difference in physical size between wearers to curb a decrease in assist force transmission efficiency, is highly capable of following movement of a wearer, and during a walking motion, enables the wearer to walk easily without generating an assist force. 
     An aspect of the present disclosure provides an assist apparatus. The assist apparatus includes: a shoulder harness to be fitted to the right and left shoulder regions of a wearer; an actuator provided in the shoulder harness; a power transmission member connected to the actuator; a pulley support portion that receives a force transmitted from the power transmission member, is to be disposed within a region from the shoulder regions to a waist region on the back side of the wearer, and supports a leg-side pulley, the leg-side pulley being a pulley to be disposed below the pulley support portion within the region from the shoulder regions to the waist region of the wearer; a knees-linking member that is an elongated member looped around the leg-side pulley; a left knee harness to be fitted to the left knee region of the wearer, the left knee harness being connected to a first end of the knees-linking member; a right knee harness to be fitted to the right knee region of the wearer, the right knee harness being connected to a second end of the knees-linking member; a posture detection device that detects a posture of the wearer; and a control device that controls the actuator based on information of the posture of the wearer, the posture being detected by the posture detection device. 
     With the above configuration, since the shoulder harness, the left knee harness and the right knee harness to be fitted to the wearer are separated from one another, the assist apparatus is light and is highly capable of following movement of the wearer. Also, the wearer only needs to fit the shoulder harness to the right and left shoulder regions, the waist harness to the waist region, the left knee harness to the left knee region, and the right knee harness to the right knee region (the shoulder harness, the left knee harness and the right knee harness are separated from one another). Consequently, irrespective of differences in physical size, each of wearers can fit the respective members to respective proper positions on the wearer&#39;s body, enabling curbing a decrease in assist force transmission efficiency. Also, the left knee harness and the right knee harness are linked via the knees-linking member (for example, a belt or a cable for power transmission), and when the walker walks, the knees-linking member looped around the leg-side pulley just moves forward and backward with almost no operation of the actuator (for example, an electric motor). Therefore, during a walking motion, the wearer can walk easily without generating an assist force. 
     In the assist apparatus, a first end of the power transmission member may be connected to the actuator. A second end of the power transmission member may be connected to the shoulder harness via a length adjustment device. The length adjustment device may be provided in the shoulder harness and may be capable of being set to one of a released state and a locked state. The released state may be a state in which winding and unwinding of the power transmission member are possible and the locked state may be a state in which winding and unwinding of the power transmission member are prohibited. 
     With the above configuration, the length adjustment device enables a length of the power transmission member when the wearer wears the assist apparatus to be adjusted according to the physical size of the wearer, which is convenient. 
     The assist apparatus may further include a left hip harness to be fitted to a left hip region of the wearer, and a right hip harness to be fitted to a right hip region of the wearer. A left guide portion that enables the knees-linking member to be inserted through the left guide portion and guides the knees-linking member from the leg-side pulley toward the left knee harness may be provided in the left hip harness. A right guide portion that enables the knees-linking member to be inserted through the right guide portion and guides the knees-linking member from the leg-side pulley toward the right knee harness may be provided in the right hip harness. 
     With the above configuration, inclusion of the left hip harness provided with the left guide portion that guides the knees-linking member from the leg-side pulley toward the left knee harness and the right hip harness provided with the right guide portion that guides the knees-linking member from the leg-side pulley toward the right knee harness enables curbing a decrease in assist force transmission efficiency. 
     In the assist apparatus, the power transmission member may be either one of a first belt having a first predetermined width and a first cable having a first predetermined diameter, and the knees-linking member may be either one of a second belt having a second predetermined width and a second cable having a second predetermined diameter. 
     With the above configuration, use of the first belt or the first cable as the power transmission member and use of the second belt or the second cable as the knees-linking member enable easily and properly providing the power transmission member and the knees-linking member. 
     In the assist apparatus, the knees-linking member may be a second belt having a second predetermined width and a leg-side pulley rotation axis that is a rotation axis of the leg-side pulley may be set in a right-left direction of the wearer. 
     With the above configuration, the second belt is used as the knees-linking member and the leg-side pulley rotation axis is set in the right-left direction of a wearer to, when the second belt comes into contact with the wearer&#39;s body, make a belt surface come into contact with the wearer&#39;s body. In other words, in comparison with the case where the leg-side pulley rotation axis is set in a front-rear direction of the wearer, the area of contact when the second belt comes into contact with the wearer can be made larger. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
         FIG. 1  is a back view illustrating an example configuration of an assist apparatus according to a first embodiment; 
         FIG. 2  is a back view illustrating an example of a wearer wearing the assist apparatus according to the first embodiment; 
         FIG. 3  is a left side view illustrating an example of a wearer wearing the assist apparatus according to the first embodiment; 
         FIG. 4  is a perspective view illustrating assist operations of the assist apparatus according to the first embodiment when a wearer has a stooped posture; 
         FIG. 5  is a block diagram illustrating a control configuration of the assist apparatus; 
         FIG. 6  is a flowchart illustrating “assist processing” performed by a control device of the assist apparatus; 
         FIG. 7  is a diagram illustrating lifting work of a wearer; 
         FIG. 8  is a diagram illustrating change in a forward-tilting angle and a lifting assist torque of a stepping motor over time when a wearer performs lifting work; 
         FIG. 9  is a diagram illustrating lowering work of a wearer; 
         FIG. 10  is a diagram illustrating change in a forward-tilting angle and a lowering assist torque of a stepping motor over time when a wearer performs lowering work; 
         FIG. 11  is a perspective view illustrating an example configuration of an assist apparatus according to a second embodiment; 
         FIG. 12  is a back view illustrating an example configuration of an assist apparatus according to the third embodiment; 
         FIG. 13  is a back view illustrating an example of a wearer wearing the assist apparatus according to the third embodiment; 
         FIG. 14  is a left side view illustrating an example of a wearer wearing the assist apparatus according to the third embodiment; 
         FIG. 15  is a perspective view illustrating assist operations of the assist apparatus according to the third embodiment when a wearer has a stooped posture; and 
         FIG. 16  is a perspective view illustrating an example configuration of an assist apparatus according to a fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     First to fourth embodiments, each of which is an embodiment of an assist apparatus according to the present disclosure, will be described in detail below with reference to the drawings. First, a schematic configuration of an assist apparatus  1 A according to a first embodiment will be described based on  FIGS. 1 to 5 . 
     As illustrated in  FIGS. 1 to 4 , an assist apparatus  1 A includes, e.g., a shoulder harness  3  to be fitted to the upper back region and right and left shoulder regions of a wearer, a belt-like waist harness  5  to be fitted to the waist region of the wearer, a right hip harness  7 R to be fitted to the right hip region of the wearer, a left hip harness  7 L to be fitted to the left hip region of the wearer, a right knee harness  9 R to be fitted to the right knee region, including a region below the right knee, of the wearer and a left knee harness  9 L to be fitted to the left knee region, including a region below the left knee, of the wearer. The shoulder harness  3 , the waist harness  5 , the right hip harness  7 R, the left hip harness  7 L, the right knee harness  9 R and the left knee harness  9 L are each formed of, e.g., fabric having a certain degree of flexibility. 
     A pair of shoulder belts  11  and a pair of armpit belts  12  for fixing the shoulder harness  3  to the right and left shoulder regions of the wearer are provided in the shoulder harness  3 . Also, an electric motor  25 A and a motor pulley  25 B included in an actuator  25 , and a transmission member length adjustment device  26 , etc., are provided in the shoulder harness  3 . The shoulder belts  11  and the armpit belts  12  can be adjusted in length via locking members such as belts and buckles or hook-and-loop fasteners and can be adjusted in degree of fitting of the shoulder harness  3  to the wearer. The shoulder harness  3  is fitted to the right and left shoulder regions of the wearer and is deformable along the body shape of the wearer. 
     In the belt-like waist harness  5 , e.g., a power supply unit  38  that supplies electric power to the electric motor  25 A and devices inside a control box  35 , and the control box  35  that receives, e.g., a motor driver circuit and a control device are provided. 
     The waist harness  5  is fitted to the waist region of the wearer and is deformable along the body shape of the wearer. 
     Also, the right hip harness  7 R to be fitted to the right hip region of the wearer and the left hip harness  7 L to be fitted to the left hip region of the wearer are joined to a lower edge of the waist harness  5 . The right hip harness  7 R and the left hip harness  7 L are formed of, for example, a member that is more stretchable than the shoulder harness  3 . Also, a right thigh fixing portion  12 R to be fixed to the upper part of the right thigh is provided at a lower end of the right hip harness  7 R and a left thigh fixing portion  12 L to be fixed to the upper part of the left thigh is provided at a lower end of the left hip harness  7 L. Also, a belt  13  for fastening and fixing the right hip harness  7 R around the upper part of the right thigh of the wearer is provided on the lower side of the right hip harness  7 R and a belt  13  for fastening and fixing the left hip harness  7 L to the upper part of the left thigh of the wearer is provided on the lower side of the left hip harness  7 L. The left hip harness  7 L is fitted to the left hip region of the wearer and is deformable along the body shape of the wearer and the right hip harness  7 R is fitted to the right hip region of the wearer and is deformable along the body shape of the wearer. 
     A right guide portion  16 R that allows a knees-linking member  22  to be inserted therethrough and guides the knees-linking member  22  from a leg-side pulley  32  toward the right knee harness  9 R is provided in the right hip harness  7 R. Likewise, a left guide portion  16 L that allows the knees-linking member  22  to be inserted therethrough and guides the knees-linking member  22  from the leg-side pulley  32  toward the left knee harness  9 L is provided in the left hip harness  7 L. The right guide portion  16 R and the left guide portion  16 L are each formed in a tubular shape that is vertically long in front view, by sewing fabric having a rectangular shape that is substantially vertically long in front view in the vertical direction. Also, the right guide portion  16 R and the left guide portion  16 L are each formed of, for example, a member that is more stretchable than the shoulder harness  3 . 
     Each of the waist harness  5  and the belts  13  can be adjusted in length via a locking member such as a belt and a buckle or a hook-and-loop fastener, and the degree of fitting of each of the waist harness  5 , the right hip harness  7 R and the left hip harness  7 L to the wearer is adjustable. Therefore, when the wearer makes a stooping motion with the left thigh fixing portion  12 L and the right thigh fixing portion  12 R fixed via the respective belts  13 , the right hip harness  7 R and the left hip harness  7 L, and the right guide portion  16 R and the left guide portion  16 L smoothly expand and contract along the right and left thigh regions because of each being formed of a highly stretchable member. 
     The left knee harness  9 L and the right knee harness  9 R are each formed of, e.g., fabric having a certain degree of flexibility, form a shape that is symmetrical in a right-left direction and are disposed on the back sides of the left knee and the right knee, respectively. An upper belt  18 L to be fastened and fixed around a region above the left knee and a lower belt  19 L to be fastened and fixed around the region below the left knee are provided in the left knee harness  9 L. An upper belt  18 R to be fastened and fixed around a region above the right knee and a lower belt  19 R to be fastened and fixed around the region below the right knee are provided in the right knee harness  9 R. The left knee harness  9 L is connected to one end of the knees-linking member  22 , is fitted to the left knee region, including the region below the left knee, of the wearer and is deformable along the body shape of the wearer. Likewise, the right knee harness  9 R is connected to another end of the knees-linking member  22 , is fitted to the right knee region, including the region below the right knee, of the wearer and is deformable along the body shape of the wearer. Note that in the left knee harness  9 L and the right knee harness  9 R, the lower belts  19 L,  19 R are essential but the upper belts  18 L,  18 R may be omitted. 
     Fitting the left knee harness  9 L and the right knee harness  9 R to the region below the left knee in the left knee region and the region below the right knee in the right knee region of the wearer, respectively, is more preferable because an effect of curbing displacement caused by a force of being pulled from above is exerted by the respective protruding parts around the patellae (kneecaps) of the knees. As described above, the left knee harness  9 L and the right knee harness  9 R are fitted to the knee regions of the wearer, and here, the “knee region” is a region around the left knee or the right knee of the wearer, the region including regions above and below the relevant knee and enabling the relevant knee to be stably held without displacement (the region partly including the thigh region and the shin). 
     Each of the upper belts  18 L,  18 R and the lower belts  19 L,  19 R is adjustable in length via a locking member such as a belt and a buckle or a hook-and-loop fastener and the respective degrees of fitting of the left knee harness  9 L and the right knee harness  9 R to the wearer are adjustable. Therefore, the upper belts  18 L,  18 R and the lower belts  19 L,  19 R are fastened and fixed around the regions above the left knee and the right knee and the regions below the left knee and the right knee, respectively, preventing hindering the wearer from making a stooping motion and a walking motion. 
     Since the upper belts  18 L,  18 R and the lower belts  19 L,  19 R are fastened and fixed around the regions above the left knee and the right knee and the regions below the left knee and the right knee, respectively, as described later, during a stooping motion of the wearer, when an upward pulling force is applied to the knees-linking member  22  with the one end and the other end connected to the left knee harness  9 L and the right knee harness  9 R, respectively (see  FIG. 4 ), upward displacement of the left knee harness  9 L and the right knee harness  9 R can effectively be curbed. 
     The actuator  25  includes, e.g., the electric motor  25 A and the motor pulley  25 B. The actuator  25  is provided in the shoulder harness  3  or the waist harness  5 ; and the present embodiment indicates an example in which the actuator  25  is provided in the shoulder harness  3 . Also, the other end side (or the one end side) of a power transmission member  21  is connected to the motor pulley  25 B. The one end side (or the other end side) of the power transmission member  21  is connected to the transmission member length adjustment device  26 . Note that either of the end portions of the power transmission member  21  may be “one end”. The electric motor  25 A is driven by a control signal from a control device  52  to wind or unwind the power transmission member  21 . Also, rotation detection means  25 E (for example, a rotary encoder) is provided in the electric motor  25 A and the rotation detection means  25 E outputs a detection signal according to rotation of the electric motor  25 A to the control device  52 . Note that the rotation detection means  25 E is not limited to a rotary encoder and may be any of various rotational angle detectors (rotation number detection device) including a Hall element, a Hall IC, a potentiometer and a resolver. Also, as illustrated in  FIG. 4 , an electric motor rotation axis  25 J, which is a rotation axis of the electric motor  25 A, is set in the right-left direction of the wearer and a length adjustment device rotation axis  26 J, which is a rotation axis of the transmission member length adjustment device  26 , is set in the right-left direction of the wearer. Note that the actuator  25  does not need to be a winding device that performs winding and unwinding and may be an actuator that makes a linear motion. 
     The power transmission member  21  is a first belt having a first predetermined width or a first cable having a first predetermined diameter; the present embodiment indicates an example in which the power transmission member  21  is the first belt. The power transmission member  21  is a bendable elongated member made of, for example fabric, and includes the one end connected to the transmission member length adjustment device  26  attached to the shoulder harness  3  and the other end connected to the motor pulley  25 B. Note that the transmission member length adjustment device  26  may be omitted and the one end of the power transmission member  21  may be fixed to the shoulder harness  3 . The power transmission member  21  bending so as to sag down is looped around a back torso-side pulley  31 . 
     The transmission member length adjustment device  26  is provided in the shoulder harness  3  and the one end of the power transmission member  21  is connected to the transmission member length adjustment device  26 . The transmission member length adjustment device  26  can be set to either one of a released state in which winding and unwinding of the connected power transmission member  21  are possible and a locked state in which winding and unwinding of the connected power transmission member  21  are prohibited, enables a length of the power transmission member  21  (for example, a length of the sagging U-shape portion) to be adjusted according to the body shape of the wearer and thus enables optimum (effective) transmission of an assist force. 
     The back torso-side pulley  31  provided in a pulley support portion  31 Z is a moving pulley, the power transmission member  21  bending so as to sag down is looped around the back torso-side pulley  31  and the back torso-side pulley  31  is disposed within the region from the shoulder region to the waist region on the back side of the wearer. Note that a diameter of the back torso-side pulley  31  is set to be a proper value as well as an assist target torque, an output torque of the electric motor  25 A, a diameter of the motor pulley  25 B and a diameter of the leg-side pulley  32 . Note that, as illustrated in  FIG. 4 , a back torso-side pulley rotation axis  31 J, which is a rotation axis of the back torso-side pulley  31 , (or a center axis ( 31 J) of a part of the pulley support portion  31 Z, the part corresponding to the position of the back torso-side pulley  31 ), is set in the right-left direction of the wearer. Consequently, even if the power transmission member  21  comes into contact with the wearer, the area of the contact between the wearer and the power transmission member  21  can be made larger in comparison with the case where the back torso-side pulley rotation axis  31 J is set in a front-rear direction of the wearer. The leg-side pulley  32  is connected to the back torso-side pulley  31  via the pulley support portion  31 Z. Note that the back torso-side pulley  31  may be omitted and the part of the pulley support portion  31 Z, the part corresponding to the position of the back torso-side pulley  31 , may be replaced with a non-rotating columnar portion (columnar portion including a smooth outer circumferential surface and having a diameter corresponding to the diameter of the back torso-side pulley), and where the back torso-side pulley  31  is omitted, (the columnar portion of) the pulley support portion  31 Z corresponds to the moving pulley. 
     Then, the power transmission member  21  transmits (adjusts) power (a winding force, an unwinding force or a tensional force) of the actuator  25  to move the back torso-side pulley  31 , the pulley support portion  31 Z and the leg-side pulley  32  upward or downward. In other words, the power of the actuator  25  is transmitted to the power transmission member  21  to move the back torso-side pulley  31 , the pulley support portion  31 Z and the leg-side pulley  32  upward or downward. Then, the force of upward or downward movement transmitted to the leg-side pulley  32  (force between the back torso region and the leg region) acts on the leg side (knee region) via the knees-linking member  22 . Note that the power transmission member  21  does not necessarily need to be a belt. For example, the power transmission member  21  may be a linear member that moves upward and downward, the linear member supporting the rotation shaft portion (pulley support portion  31 Z) of the leg-side pulley  32  so as to move the leg-side pulley  32  upward and downward, being connected to an output of the actuator  25 , and being formed of, e.g., flexible resin or metal (that is flexed according to the body shape of the wearer). 
     The leg-side pulley  32  is a pulley and is connected (joined) to the back torso-side pulley  31  via the pulley support portion  31 Z. The leg-side pulley  32  is disposed below the back torso-side pulley  31  within the region from the shoulder region to the waist region of the wearer. The knees-linking member  22  is looped around the leg-side pulley  32 . Also, a leg-side pulley rotation axis  32 J, which is a rotation axis of the leg-side pulley  32 , is set in the right-left direction of the wearer. Consequently, even if the knees-linking member  22  comes into contact with the wearer, the area of the contact between the wearer and the knees-linking member  22  can be made larger in comparison with the case where the leg-side pulley rotation axis  32 J is set in the front-rear direction of the wearer. 
     The knees-linking member  22  is a second belt having a second predetermined width or a second cable having a second predetermined diameter; the present embodiment indicates an example in which the knees-linking member  22  is the second belt. The knees-linking member  22  is a bendable elongated member made of, for example, fabric. The one end side of the knees-linking member  22  is connected to the left knee harness  9 L through the left guide portion  16 L provided in the left hip harness  7 L. The other end side of the knees-linking member  22  is connected to the right knee harness  9 R through the right guide portion  16 R provided in the right hip harness  7 R. A part around a center in a longitudinal direction of the knees-linking member  22  is looped around the leg-side pulley  32 . Note that length adjustment means for enabling adjustment of a length of the knees-linking member  22  from the left knee harness  9 L to the right knee harness  9 R is provided in each of a part of connection between the knees-linking member  22  and the left knee harness  9 L and a part of connection between the knees-linking member  22  and the right knee harness  9 R. 
     Since the left knee harness  9 L and the right knee harness  9 R are connected to the one end and the other end of the single knees-linking member  22 , respectively, when the wearer walks, the wearer can easily walk. More specifically, during walking, when the wearer swings the right leg forward and the left leg rearward, the knees-linking member  22  is pulled up from the left leg side and is pulled out to the right leg side as viewed from the leg-side pulley  32 . When the wearer swings the right leg rearward and the left leg forward, the knees-linking member  22  is pulled up from the right leg side and pulled out to the left leg side as viewed from the leg-side pulley  32 . In other words, when the wearer walks, the knees-linking member  22  looped around the leg-side pulley  32  just moves back and forth between the left leg side and the right leg side, and thus, the wearer can walk with almost no actuation of the actuator  25 . Therefore, the wearer can walk easily (in this case, the leg-side pulley  32  operates like a fixed pulley). 
     The control box  35  is provided, for example, on an outer surface of a part of the waist harness  5 , the part corresponding to the right waist region of the wearer. The control box  35  is a substantially rectangular parallelepiped box body that receives, e.g., a control unit  51  that controls driving of the electric motor  25 A, etc. For example, a main switch  36 A, a lifting assist switch  36 B and a lowering assist switch  36 C are disposed at an upper end surface of the control box  35 . Each time the main switch  36 A is pressed, the main switch  36 A alternately outputs either one of an activation signal and a halt signal to the control unit  51 , that is, the main switch  36 A is an on-off switch of the control unit  51 . The lifting assist switch  36 B, upon being pressed, outputs an ON signal for performing a lifting assist operation to the control unit  51 . The lowering assist switch  36 C, upon being pressed, outputs an ON signal for performing a lowering assist operation to the control unit  51 . 
     The power supply unit  38  is provided, for example, on an outer surface of a part of the waist harness  5 , the part corresponding to the left waist region of the wearer. The power supply unit  38  is a substantially rectangular parallelepiped box body that supplies electric power to the control box  35  and the electric motor  25 A. The power supply unit  38  receives a battery (for example, a lithium ion battery). For example, an ON switch  39 A and an OFF switch  39 B are disposed at an upper end surface of the power supply unit  38 . Upon the wearer pressing the ON switch  39 A, an electric power supply start signal is output to the power supply unit  38 , and supply of electric power to the control box  35  and the electric motor  25 A is thus started. Upon the wearer pressing the OFF switch  39 B, an electric power shut-off signal is output to the power supply unit  38 , and the supply of electric power to the power control box  35  and the electric motor  25 A is shut off. 
     A back triaxial acceleration and angular velocity sensor  41  is a posture detection device that detects a posture of the wearer, and is provided, for example, in a part, in a center in the right-left direction, of an outer surface of the shoulder harness  3 , the part corresponding to the upper side of the back region of the wearer. Also, a left-leg triaxial acceleration and angular velocity sensor  42 L is a posture detection device that detects a posture of the wearer, and is provided, for example, in a part of an outer surface of the left hip harness  7 L, the part corresponding to a position in the vicinity of a proximal end portion of the belt  13 . Also, the right-leg triaxial acceleration and angular velocity sensor  42 R is a posture detection device that detects a posture of the wearer, and is disposed, for example, in a part of an outer surface of the right hip harness  7 R, the part corresponding to a position in the vicinity of a proximal end portion of the belt  13 . 
     For each of three direction axes, X-axis, Y-axis and Z-axis, each of the triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R measures an acceleration and an angular velocity of rotation around the axis. Then, each of the triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R outputs, for example, a detection signal according to an inclination in each of the three directions, the X-axis, the Y-axis and the Z-axis, to the control device  52  (see  FIG. 5 ). Note that the Z-axis direction is the vertical direction; the X-axis direction is the right-left direction of the wearer and the Y-axis direction is the front-rear direction of the wearer. 
     Here, an example in which when a wearer  61  wearing the assist apparatus  1 A configured as described above has a stooped posture, the electric motor  25 A is driven to rotate (normally) in a direction in which the power transmission member  21  is wound will be described with reference to  FIG. 4 . 
     As illustrated in  FIG. 4 , when the wearer  61  wearing the assist apparatus  1 A has a stooped posture, upon the electric motor  25 A being driven to rotate (normally) and winding the power transmission member  21 , a rearward acting force F 1  is generated as a result of a downward pulling force from the power transmission member  21  acting on the opposite end portions (in this case, the motor pulley  25 B and the transmission member length adjustment device  26 ) of the power transmission member  21 . In other words, the acting force F 1  is generated to make the upper half of the wearer&#39;s body having a stooped posture rise. 
     Also, upon the power transmission member  21  being wound, the back torso-side pulley  31  and the leg-side pulley  32  are pulled upward. Note that the back torso-side pulley  31  is a moving pulley that moves relative to the power transmission member  21  and the electric motor  25 A can pull the back torso-side pulley  31  and the leg-side pulley  32  up with smaller torque. The output torque of the electric motor  25 A may be half of a required torque, which is an assist force. Therefore, the electric motor  25 A can be made smaller and lighter. 
     Upon the leg-side pulley  32  being pulled up, the knees-linking member  22  is pulled upward, and the left knee harness  9 L and the right knee harness  9 R connected to the knees-linking member  22  are pulled upward. Then, a rearward acting force F 2  is generated in each of the left knee harness  9 L and the right knee harness  9 R. 
     Consequently, a load on the back muscle, quadriceps, etc., of the wearer  61  having a stooped posture can be reduced, enabling effectively assisting a package lifting motion and a package lowering motion. Note that a load on the muscles in the waist region of the wearer  61  having a stooped posture can be reduced, enabling prevention of lower back pain. 
     Also, when a part of the knees-linking member  22 , the part extending from the left knee harness  9 L to the leg-side pulley  32  through the left guide portion  16 L is pulled up, an acting force F 3  of pushing the left hip region of the wearer forward is generated. Likewise, when a part of the knees-linking member  22 , the part extending from the right knee harness  9 R to the leg-side pulley  32  through the right guide portion  16 R is pulled up, an acting force F 3  of pushing the right hip region of the wearer forward is generated. 
     Note that disposing a guard panel P in an area, between the shoulder harness  3  and the waist harness  5 , in which the wearer&#39;s body is not covered and the power transmission member  21  and the knees-linking member  22  are likely to come into contact with the body prevents the wearer and the power transmission member  21  and the knees-linking member  22  from coming into contact with each other and thus is more preferable. 
     Next, an input to and an output from the control unit  51  of the assist apparatus  1 A will be described with reference to  FIG. 5 . As illustrated in  FIG. 5 , the control unit  51  received in the control box  35  includes, e.g., the control device (hereinafter referred to as “ECU”)  52  that controls the entirety of the assist apparatus  1 A, and a motor driver  53 . The power supply unit  38  supplies electric power to the ECU  52  and the motor driver  53  included in the control unit  51 . The motor driver  53  is an electronic circuit that outputs a drive current for driving the electric motor  25 A, based on a control signal from the ECU  52 . 
     The ECU  52  includes, e.g., a CPU, a flash ROM (or an EEPROM), a RAM, a timer and a backup RAM. The CPU performs various arithmetic processing based on various programs and parameters stored in the Flash ROM (or the EEPROM). Also, the RANI temporarily stores, e.g., results of arithmetic operations in the CPU and data input from detection devices. The backup RAM stores, for example, data, etc., that should be stored, when the electric motor  25 A is stopped. 
     An operation signal from the main switch  36 A is input to the ECU  52 . A rotational angle detection signal from the rotation detection means  25 E that outputs a detection signal according to rotation of the electric motor  25 A is input to the ECU  52 . A detection signal according to inclinations in three directions, the X-axis, the Y-axis and the Z-axis, is input to the ECU  52  from each of the back triaxial acceleration and angular velocity sensor  41 , the left-leg triaxial acceleration and angular velocity sensor  42 L and the right-leg triaxial acceleration and angular velocity sensor  42 R. Furthermore, an operation signal (press signal) is input to the ECU  52  from each of the lifting assist switch  36 B and the lowering assist switch  36 C provided at the control box  35 . 
     Operation signals (press signals) from the ON switch  39 A and the OFF switch  39 B are input to the power supply unit  38 . Upon an operation signal from the ON switch  39 A being input, the power supply unit  38  supplies electric power to the ECU  52  and the motor driver  53 . Upon an operation signal from the OFF switch  39 B being input, the power supply unit  38  shuts off the supply of electric power to the ECU  52  and the motor driver  53 . 
     Next, assist processing performed by the ECU  52  of the assist apparatus  1 A configured as described above will be described with reference to  FIGS. 6 to 10 . Note that the program indicated in the flowchart in  FIG. 6  is stored in the flash ROM (or the EEPROM) of the ECU  52  and is executed by the ECU  52  every predetermined period of time (for example, every several milliseconds to several tens of milliseconds) upon the wearer turning the main switch  36 A on. Upon the wearer turning the main switch  36 A on, the ECU  52  advances the processing to step S 11  illustrated in  FIG. 6 . The flowchart in  FIG. 6  will be described below. 
     In step S 11 , the ECU  52  determines whether or not the lifting assist switch  36 B has been pressed, that is, whether or not an ON signal has been input from the lifting assist switch  36 B. Then, if it is determined that the lifting assist switch  36 B has been pressed, that is, an ON signal has been input from the lifting assist switch  36 B (Yes), the ECU  52  advances the processing to step S 12 , and if an ON signal has not been input from the lifting assist switch  36 B (No), advances the processing to step S 19 . 
     If the ECU  52  advances the processing to step S 12 , the ECU  52  determines whether or not a stooping motion has started, and if it is determined that a stooping motion has started (Yes), advances the processing to step S 13 , and if it is determined that a stooping motion has not started (No), advances the processing to step S 12 . 
     Here, a method of determining a start of a stooping motion will be described with reference to  FIG. 7 . As illustrated in  FIG. 7 , the ECU  52  (see  FIG. 1 ) detects a forward-tilting angle θL(t) of the waist region relative to the left thigh region from detection signals of accelerations of the axes in the three directions, the X-axis, the Y-axis and Z-axis, input from the back triaxial acceleration and angular velocity sensor  41  and the left-leg triaxial acceleration and angular velocity sensor  42 L and angular velocities of rotation around the respective axes and chronologically stores the forward-tilting angle θL(t) in the RAM. Also, the ECU  52  detects a forward-tilting angle θR(t) of the waist region relative to the right thigh region from detection signals of accelerations of the three directions axes, the X-axis, the Y-axis and the Z-axis, input from the back triaxial acceleration and angular velocity sensor  41  and the right-leg triaxial acceleration and angular velocity sensor  42 R and angular velocities of rotation around the respective axes, and chronologically stores the forward-tilting angle θR(t) in the RAM. 
     Then, the ECU  52  calculates a forward-tilting angle θ(t) of the wearer according to Expression (1) below and chronologically stores the forward-tilting angle θ(t) in the RAM. 
       θ( t )=(θ L ( t )+θ R ( t ))/2   (1)
 
     Subsequently, the ECU  52  determines whether or not the forward-tilting angle θ(t) is not smaller than a first criterion angle θD 1  (for example, approximately 5 degrees). Then, if it is determined that the forward-tilting angle θ(t) is not smaller than the first criterion angle θD 1 , the ECU  52  determines that the wearer has started a stooping motion (S 12 : Yes). On the other hand, if it is determined that the forward-tilting angle θ(t) is smaller than the first criterion angle θD 1 , the ECU  52  determines that the wearer has not yet started a stooping motion (S 12 : No). Note that the first criterion angle θD 1  is stored in advance in the flash ROM (or the EEPROM). Also, the forward-tilting angle θ(t) when the wearer stands upright is “0 degrees”. 
     As illustrated in  FIG. 6 , if it is determined in step S 12  that the wearer has not yet started a stooping motion (S 12 : No), the ECU  52  performs the processing in step S 12  again and waits until the wearer starts a stooping motion. On the other hand, if it is determined in step S 12  that the wearer has started a stooping motion (S 12 : Yes), the ECU  52  advances the processing to step S 13 . 
     In step S 13 , the ECU  52  calculates the forward-tilting angle θ(t) of the wearer from detection signals of accelerations and angular velocities input from the respective triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R, according to Expression (1) above. Then, the ECU  52  drives the electric motor  25 A to rotate in a (reverse) rotation direction with a substantially-constant small stooping assist torque, based on the number of rotations detected by the rotation detection means  25 E, according to the forward-tilting angle θ(t) of the wearer, that is, according to the stooping motion to unwind (pay out) the power transmission member  21  while adjusting an amount of the power transmission member  21  unwound, and advances the processing to step S 14 . Note that the small stooping assist torque is stored in advance in the flash ROM (or the EEPROM). 
     More specifically, as illustrated in  FIGS. 7 and 8 , the stooping assist torque is generated in the (reverse) rotation direction of the electric motor  25 A, that is, a lowering direction so as not to hinder the stooping motion. Here, description will be provided on the premise that the sign of torque in the lowering direction is + (positive) and the sign of torque in a lifting direction is − (negative). Then, the ECU  52  advances the processing to step S 14 . 
     In step S 14 , the ECU  52  determines whether or not the stooping motion has finished, and if it is determined that the stooping motion has finished (Yes), advances the processing to step S 15 , and if it is determined that the stooping motion has not yet finished (No), returns the processing to step S 13 . More specifically, as illustrated in  FIGS. 7 and 8 , the ECU  52  determines whether or not an increase of the forward-tilting angle θ(t) of the wearer has substantially stopped. Then, if it is determined that the stooping motion has not finished, that is, if it is determined that the forward-tilting angle θ(t) is increasing (S 14 : No), the ECU  52  performs processing in step S 13  onwards again. 
     On the other hand, if it is determined that the stooping motion has finished, that is, if it is determined that the forward-tilting angle θ(t) is not increasing (S 14 : Yes), the ECU  52  advances the processing to step S 15 . More specifically, as illustrated in  FIG. 8 , the wearer starts a stooping motion from an upright standing state at time  0 , gradually increases the forward-tilting angle θ(t), and finishes the stooping motion at time T 11 . 
     If the ECU  52  advances the processing to step S 15 , the ECU  52  halts the electric motor  25 A. Then, the ECU  52  determines whether or not the wearer has started a lifting motion, and if it is determined that the wearer has started a lifting motion (Yes), advances the processing to step S 16 , and if it is determined that the wearer has not started a lifting motion (No), performs the processing to step S 15  again. More specifically, the ECU  52  calculates the forward-tilting angle θ(t) of the wearer from detection signals of accelerations and angular velocities input from the respective triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R, according to Expression (1) above. Subsequently, the ECU  52  determines whether or not the forward-tilting angle θ(t) has decreased by a second criterion angle θD 2  (for example, approximately 3 degrees) or more. 
     Then, if it is determined that the forward-tilting angle θ(t) has decreased by the second criterion angle θD 2  (for example, approximately 3 degrees) or more, the ECU  52  determines that the wearer has started a lifting motion (S 15 : Yes). On the other hand, if it is determined that the forward-tilting angle θ(t) has not decreased by the second criterion angle θD 2  (for example, approximately 3 degrees) or more, the ECU  52  determines that the wearer has not started a lifting motion (S 15 : No). 
     Then, if it is determined that the wearer has not started a lifting motion (S 15 : No), the ECU  52  performs the processing in S 15  again. On the other hand, if it is determined that the wearer has started a lifting motion (S 15 : Yes), the ECU  52  advances the processing to step S 16 . 
     When the ECU  52  advances the processing to step S 16 , the ECU  52  calculates the forward-tilting angle θ(t) of the wearer from detection signals of accelerations and angular velocities from the respective triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R, according to Expression (1) above. 
     Then, the ECU  52  drives the electric motor  25 A to rotate in a (normal) rotation direction with a predetermined lifting assist torque, based on the number of rotations detected by the rotation detection means  25 E, according to the forward-tilting angle θ(t) of the wearer, that is, according to the lifting motion to wind the power transmission member  21  while adjusting the amount of the power transmission member  21  wound, and advances the processing to step S 17 . Therefore, as illustrated in  FIG. 8 , the lifting assist torque is an assist torque in the lifting direction (− (negative) side in  FIG. 8 ), enabling reduction of load on the waist region of the wearer and proper assistance of the lifting work. Note that the predetermined lifting assist torque is stored in advance in the flash ROM (or the EEPROM). 
     In step S 17 , the ECU  52  determines whether or not the lifting motion has finished, and if it is determined that the lifting motion has finished (Yes), advances the processing to step S 18 , and if it is determined that the lifting motion has not finished (No), advances the processing to step S 16 . More specifically, as illustrated in  FIG. 8 , after the wearer starts the lifting motion at time T 12 , the ECU  52  determines whether or not the forward-tilting angle θ(t) of the wearer has decreased to substantially “0 degrees”, that is, whether or not the wearer has entered an upright standing state. Then, if it is determined that the lifting motion has not finished, that is, if the forward-tilting angle θ(t) is decreasing (S 17 : No), the ECU  52  performs the processing in step S 16  onwards again. 
     On the other hand, if it is determined that the lifting motion has finished, that is, if it is determined that the forward-tilting angle θ(t) has reached substantially “0 degrees” and the wearer has entered an upright standing state (S 17 : Yes), the ECU  52  advances the processing to step S 18 . More specifically, as illustrated in  FIG. 8 , the ECU  52  determines that the wearer has finished the lifting motion at time T 13 , and advances the processing to step S 18 . 
     In step S 18 , the ECU  52  stops electric motor  25 A, and then, ends the processing illustrated in  FIG. 6 . 
     On the other hand, if it is determined in step S 11  that the lifting assist switch  36 B has not been pressed, that is, if it is determined that an ON signal has not been input from the lifting assist switch  36 B (S 11 : No), the ECU  52  advances the processing to step S 19 . 
     If the processing advances to step S 19 , the ECU  52  determines whether or not the lowering assist switch  36 C has been pressed, that is, whether or not an ON signal has been input from the lowering assist switch  36 C. Then, if an ON signal has been input from the lowering assist switch  36 C (Yes), the ECU  52  advances the processing to step S 20 , and if an ON signal has not been input from the lowering assist switch  36 C (No), the ECU  52  ends the processing illustrated in  FIG. 6 . Then, if it is determined that the lowering assist switch  36 C has been pressed, that is, an ON signal has been input from the lowering assist switch  36 C (S 19 : Yes), the ECU  52  advances to step S 20 . 
     If the processing advances to step S 20 , the ECU  52  determines whether or not the wearer has started a lowering motion, and if it is determined that the wearer has started a lowering motion (Yes), advances the processing to step S 21 , and if it is determined that the wearer has not started a lowering motion (No), returns the processing back to step S 20 . More specifically, the ECU  52  calculates the forward-tilting angle θ(t) of the wearer from detection signals of accelerations and angular velocities input from the respective triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R, according to Expression (1) above. Then, the ECU  52  determines whether or not the forward-tilting angle θ(t) is not smaller than the first criterion angle θD 1  (for example, approximately 5 degrees) or more. 
     Then, if it is determined that the forward-tilting angle θ(t) is smaller than the first criterion angle θD 1 , the ECU  52  determines that the wearer has not yet started a lowering motion (S 20 : No) and performs the processing in step S 20  onwards again. On the other hand, if it is determined that the forward-tilting angle θ(t) is not smaller than the first criterion angle θD 1 , the ECU  52  determines that the wearer has started a lowering motion (S 20 : Yes) and advances the processing to step S 21 . 
     In step S 21 , the ECU  52  calculates the forward-tilting angle θ(t) of the wearer from detection signals of accelerations and angular velocities input from the respective triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R, according to Expression (1) above. Then, the ECU  52  drives the electric motor  25 A to rotate in a (reverse) rotation direction with a predetermined lowering assist torque, based on the number of rotations detected by the rotation detection means  25 E, according to the forward-tilting angle θ(t) of the wearer, that is, according to the lowering motion to unwind (pay out) the power transmission member  21  while adjusting the amount of the power transmission member  21  unwound, and advances the processing to step S 22 . 
     Therefore, as illustrated in  FIG. 10 , the lowering assist torque is an assist torque in the lifting direction (− (negative) side in  FIG. 10 ), enabling reduction of load on the waist region of the wearer and proper assistance of the lowering work. Note that the predetermined lowering assist torque is stored in advance in the flash ROM (or the EEPROM). 
     In step S 22 , the ECU  52  determines whether or not the lowering motion has finished, and if it is determined that the lowering motion has finished (Yes), advances the processing to step S 23 , and if it is determined that the lowering motion has not finished (No), returns the processing back to step S 21 . More specifically, as illustrated in  FIGS. 9 and 10 , the ECU  52  determines whether or not an increase of the forward-tilting angle θ(t) of the wearer has substantially stopped. Then, if it is determined that the lowering motion of the wearer has not finished, that is, if it is determined that the forward-tilting angle θ(t) is increasing (S 22 : No), the ECU  52  performs the processing in step S 21  onwards again. 
     On the other hand, if it is determined that the lowering motion of the wearer has finished, that is, the forward-tilting angle θ(t) is not increasing (S 22 : Yes), the ECU  52  advances the processing to step S 23 . More specifically, as illustrated in  FIG. 10 , the wearer starts a lowering motion from an upright standing state at time  0 , gradually increases the forward-tilting angle θ(t) and finishes the lowering motion at time T 21 . 
     If the processing advances to step S 23 , the ECU  52  halts the electric motor  25 A. Then, the ECU  52  determines whether or not the wearer has started a rising motion, and if it is determined that the wearer has started a rising motion (Yes), advances the processing to step S 24 , and if it is determined that the wearer has not started a rising motion (No), returns the processing back to step S 23 . More specifically, the ECU  52  calculates the forward-tilting angle θ(t) of the wearer from detection signals of accelerations and angular velocities input from the respective triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R, according to Expression (1) above. Subsequently, the ECU  52  determines whether or not the forward-tilting angle θ(t) has decreased by the second criterion angle θD 2  (for example, approximately 3 degrees) or more. 
     If it is determined that the forward-tilting angle θ(t) has decreased by the second criterion angle θD 2  (for example, approximately 3 degrees) or more, the ECU  52  determines that the wearer has started a rising motion (S 23 : Yes). On the other hand, if it is determined that the forward-tilting angle θ(t) has not decreased by the second criterion angle θD 2  (for example, approximately 3 degrees) or more, the ECU  52  determines that the wearer has not started a rising motion (S 23 : No). 
     Then, if it is determined that the wearer has not started a rising motion (S 23 : No), the ECU  52  performs the processing in S 23  again. On the other hand, if it is determined that the wearer has started a rising motion (S 23 : Yes), the ECU  52  advances to step S 24 . 
     In step S 24 , the ECU  52  calculates the forward-tilting angle θ(t) of the wearer from detection signals of accelerations and angular velocities input from the respective triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R, according to Expression (1) above. 
     Then, the ECU  52  drives the electric motor  25 A to rotate in a (normal) rotation direction with a predetermined rising assist torque, based on the number of rotations detected by the rotation detection means  25 E, according to the forward-tilting angle θ(t) of the wearer, that is, according to the rising motion to wind the power transmission member  21  while adjusting the amount of the power transmission member  21  wound, and advances the processing to step S 25 . Therefore, as illustrated in  FIG. 10 , the lowering assist torque is an assist torque in the lifting direction (− (negative) side in  FIG. 10 ), enabling reduction of load on the waist region of the wearer and proper assistance of the lowering work. Note that the predetermined rising assist torque is stored in advance in the flash ROM (or the EEPROM). 
     In step S 25 , the ECU  52  determines whether or not the rising motion has finished, and if it is determined that the rising motion has finished (Yes), advances the processing to step S 18 , and if it is determined that the rising motion has not finished (No), returns the processing back to step S 24 . More specifically, as illustrated in  FIG. 10 , after the wearer starts a rising motion at time T 22 , the ECU  52  determines whether or not the forward-tilting angle θ(t) of the wearer has decreased to substantially “0 degrees”, that is, whether or not the wearer has entered an upright standing state. Then, if it is determined that the rising motion has not finished, that is, if it is determined that the forward-tilting angle θ(t) is decreasing (S 25 : No), the ECU  52  performs the processing in step S 24  onwards again. 
     On the other hand, if it is determined that the rising motion has finished, that is, if it is determined that the forward-tilting angle θ(t) has reached substantially “0 degrees” and the wearer has entered an upright standing state (S 25 : Yes), the ECU  52  advances the processing to step S 18 . More specifically, as illustrated in  FIG. 10 , the ECU  52  determines that the wearer has finished the rising motion at time T 23  and advances the processing to step S 18 . 
     In step S 18 , the ECU  52  stops the electric motor  25 A, and then, ends the processing illustrated in  FIG. 6 . 
     On the other hand, if it is determined in step S 19  that the lowering assist switch  36 C has not been pressed, that is, if it is determined that an ON signal has not been input from the lowering assist switch  36 C (S 19 : No), the ECU  52  ends the processing illustrated in  FIG. 6 . 
     As described in detail above, in the assist apparatus  1 A according to the present embodiment, as illustrated in  FIGS. 1 to 4 , the actuator  25  is disposed at a position within the region from the shoulder region to the waist region (shoulder harness  3  in the example in the present embodiment). Also, the power transmission member  21  is disposed so as to be connected to the motor pulley  25 B and the transmission member length adjustment device  26  and sag down. The power transmission member  21  is looped around the back torso-side pulley  31 , which is a moving pulley, and the knees-linking member  22  is looped around the leg-side pulley  32 , which is a fixed pulley connected below the back torso-side pulley  31 . Then, the left knee harness  9 L is connected to the one end of the knees-linking member  22  and the right knee harness  9 R is connected to the other end of the knees-linking member  22 . 
     Then, the ECU (control device)  52  calculates a forward-tilting angle θ(t) of a wearer (information of a posture of the wearer) from detection signals of accelerations and angular velocities input from the respective triaxial acceleration and angular velocity sensors  41 ,  42 L,  42 R, according to Expression (1) above. Then, the ECU  52  controls driving of the electric motor  25 A based on the forward-tilting angle θ(t) of the wearer to wind or unwind the power transmission member  21 . 
     The shoulder harness  3 , the waist harness  5 , the left hip harness  7 L, the right hip harness  7 R, the left knee harness  9 L and the right knee harness  9 R included in the assist apparatus  1 A are each formed of not a rigid component but, e.g., flexible fabric, enabling substantial reduction in weight and reduction of a burden in wearing. Also, use of a moving pulley for the back torso-side pulley  31  enables generation of a necessary assist force by a single relatively-small electric motor  25 A and thus further reduction in weight. 
     Also, as illustrated in  FIG. 4 , an acting force F 1  is generated on the back of a wearer having a forward-tilted posture, an acting force F 2  is generated on each of the left knee and the right knee of the wearer and an acting force F 3  is generated on each of the left hip region and the right hip region of the wearer, enabling reduction of load on the muscles of the wearer when having a forward-tilted posture, and thus enables effective assistance of a motion of lifting a package and a motion of lowering a package. 
     Furthermore, the electric motor  25 A is connected to the motor pulley  25 B with no gear provided therebetween, and thus there is no power transmission loss caused by a gear, enabling efficient assist force transmission. 
     The ECU (control device)  52  controls driving of the electric motor  25 A based on rotation number information detected by the rotation detection means  25 E to adjust a speed of winding or unwinding of the power transmission member  21 . Consequently, the speed of winding or unwinding of the power transmission member  21  can be adjusted in accordance with the forward-tilted posture of the wearer, enabling effective assistance of a lifting motion and a lowering motion of the wearer. 
     The control box  35  that receives the control unit  51  and the power supply unit  38  that supplies electric power to the ECU (control device)  52  and the motor driver  53  are attached to the waist harness  5 , enabling a wearer to freely move and perform work and thus enabling facilitation of work. 
     Next, a configuration of an assist apparatus  1 B according to a second embodiment will be described with reference to  FIG. 11 . Note that assist operations and processing in an ECU (control device) are similar to those of the first embodiment and thus description thereof will be omitted. 
     As illustrated in  FIG. 11 , in comparison with the assist apparatus  1 A according to the first embodiment illustrated in  FIG. 4 , in the assist apparatus  1 B according to the second embodiment, the power transmission member  21  that is the first belt having the first predetermined width is changed to a power transmission member  21 B that is a first cable having a first predetermined diameter and the knees-linking member  22  that is the second belt having the second predetermined width is changed to a knees-linking member  22 B that is a second cable having a second predetermined diameter. Along with the changes, a length adjustment device rotation axis  26 BJ, which is a rotation axis of a transmission member length adjustment device  26 B, is set not in a right-left direction but in a front-rear direction of a wearer. Likewise, a back torso-side pulley rotation axis  31 BJ of a back torso-side pulley  31 B and a leg-side pulley rotation axis  32 BJ of a leg-side pulley  32 B are set not in the right-left direction but in the front-rear direction of the wearer. In addition, each of a motor pulley  25 BB, the transmission member length adjustment device  26 B, the back torso-side pulley  31 B and the leg-side pulley  32 B is not a substantially columnar pulley but a pulley including a V-groove. Also, the second embodiment is similar to the first embodiment in that the leg-side pulley  32 B, which is a fixed pulley, is connected to the back torso-side pulley  31 B, which is a moving pulley, via a pulley support portion  31 ZB. 
     As a result of the above changes, the assist apparatus  1 B according to the second embodiment is further lighter relative to the assist apparatus  1 A according to the first embodiment (because of the change of the first belt and the second belt to the first cable and the second cable). Note that the power transmission member  21 , the motor pulley  25 B, the transmission member length adjustment device  26  and the back torso-side pulley  31  of the assist apparatus  1 A according to the first embodiment illustrated in  FIG. 4  may be changed to the power transmission member  21 B, the motor pulley  25 BB, the transmission member length adjustment device  26 B and the back torso-side pulley  31 B illustrated in  FIG. 11  (it is possible that the power transmission member is the first cable and the knees-linking member is the second belt). Also, the knees-linking member  22  and the leg-side pulley  32  of the assist apparatus  1 A according to the first embodiment illustrated in  FIG. 4  may be changed to the knees-linking member  22 B and the leg-side pulley  32 B illustrated in  FIG. 11  (it is possible that the power transmission member is the first belt and the knees-linking member is the second belt). 
     Next, a configuration of an assist apparatus  1 C according to a third embodiment will be described with reference to  FIGS. 12 to 15 . Note that assist operations and processing in an ECU (control device) are similar to those of the first embodiment and thus description thereof will be omitted. 
     In the assist apparatus  1 C according to the third embodiment illustrated in  FIG. 12 , a shoulder harness  3 , a waist harness  5 , a left hip harness  7 L, a right hip harness  7 R, a left knee harness  9 L and a right knee harness  9 R are the same in shape and material as those of the assist apparatus  1 A according to the first embodiment illustrated in  FIG. 1 , and thus, description thereof will be omitted. Furthermore, a power supply unit  38 , a control box  35 , a back triaxial acceleration and angular velocity sensor  41 , a left-leg triaxial acceleration and angular velocity sensor  42 L and a right-leg triaxial acceleration and angular velocity sensor  42 R are also the same as those of the assist apparatus  1 A according to the first embodiment, and thus, description thereof will be omitted. The below description will be provided mainly on differences in configuration from the assist apparatus  1 A according to the first embodiment illustrated in  FIGS. 1 to 4 . 
     An actuator  25  includes, e.g., an electric motor  25 A and a motor pulley  25 B. The actuator  25  is provided in the shoulder harness  3  or the waist harness  5 ; the present embodiment indicates an example in which the actuator  25  is provided in the waist harness  5 . The motor pulley  25 B is attached to the electric motor  25 A. Another end of a power transmission member  21 C is connected to the motor pulley  25 B. Also, rotation detection means  25 E is provided in the electric motor  25 A. The rest of the electric motor  25 A is similar to that of the electric motor according to the first embodiment, and thus, description thereof will be omitted. Note that as in the first embodiment, the actuator  25  does not necessarily need to be a winding device that performs winding and unwinding and may be an actuator that makes a linear motion. 
     The power transmission member  21 C is a first belt having a first predetermined width or a first cable having a first predetermined diameter; the present embodiment indicates an example in which the power transmission member  21 C is the first belt. The power transmission member  21 C is a bendable elongated member made of, for example, fabric, and includes one end (or the other end) connected to a leg-side pulley  32 C (pulley support portion  31 ZC that supports the leg-side pulley  32 C) and the other end (or the one end) connected to the motor pulley  25 B. Note that either of the end portions of the power transmission member  21 C may be “one end”. Also, the power transmission member  21 C is looped around a back torso-side pulley  31 C. 
     The back torso-side pulley  31 C provided on a pulley support portion  31 YC is a fixed pulley and is rotatably supported by a support  31 XC attached to the shoulder harness  3 , via a pulley support portion  31 YC. Note that a diameter of the back torso-side pulley  31 C is set to be a proper value as well as an assist target torque, an output torque of the electric motor  25 A, a diameter of the motor pulley  25 B, a diameter of the leg-side pulley  32 C, a diameter of a left leg pulley  33 CL and a diameter of a right leg pulley  33 CR. Also, as illustrated in  FIG. 15 , a back torso-side pulley rotation axis  31 CJ, which is a rotation axis of the back torso-side pulley  31 C, (or a center axis ( 31 CJ) of a part of a pulley support portion  31 YC, the part corresponding to the back torso-side pulley  31 C) is set in a right-left direction of a wearer. Consequently, even if the power transmission member  21 C comes into contact with the wearer, the area of the contact between the wearer and the power transmission member  21 C can be made larger in comparison with the case where the back torso-side pulley rotation axis  31 CJ is set in a front-rear direction of the wearer. Note that the back torso-side pulley  31 C may be omitted and a part of the pulley support portion  31 YC, the part corresponding to the position of the back torso-side pulley  31 C, may be replaced with a non-rotating columnar portion (columnar portion including a smooth outer circumferential surface and having a diameter corresponding to a diameter of the back torso-side pulley), and where the back torso-side pulley  31 C is omitted, (the columnar portion of) the pulley support portion  31 YC corresponds to the fixed pulley. 
     Then, the power transmission member  21 C transmits (adjusts) power (a winding force, an unwinding force or a tensional force) of the actuator  25  to move the leg-side pulley  32 C and the pulley support portion  31 ZC upward or downward. In other words, the power of the actuator  25  is transmitted to the power transmission member  21 C to move the leg-side pulley  32 C and the pulley support portion  31 ZC upward or downward. Then, the force of upward or downward movement transmitted to the leg-side pulley  32 C (force between the back torso region and the leg region) acts on the leg side (knee region) via the knees-linking member  22 C. Note that the power transmission member  21 C does not necessarily need to be a belt. For example, the power transmission member  21 C may be a linear member that moves upward and downward, the linear member supporting the rotation shaft portion (pulley support portion  31 YC) of the leg-side pulley  32 C so as to move the leg-side pulley  32 C and the pulley support portion  31 ZC upward and downward, being connected to an output of the actuator  25  and being formed of, e.g., flexible resin or metal (flexed according to the body shape of the wearer). 
     The leg-side pulley  32 C is a pulley and is connected to the one end of the power transmission member  21 C via the pulley support portion  31 ZC. Also, the leg-side pulley  32 C is provided below the back torso-side pulley  31 C within the region from the shoulder region to the waist region of the wearer. Also, the knees-linking member  22 C is looped around the leg-side pulley  32 C. Also, a leg-side pulley rotation axis  32 CJ, which is a rotation axis of the leg-side pulley  32 C, is set in the right-left direction of the wearer. Consequently, even if the knees-linking member  22 C comes into contact with the wearer, the area of the contact between the wearer and the knees-linking member  22 C can be made larger in comparison with the case where the leg-side pulley rotation axis  32 CJ is set in the front-rear direction of the wearer. 
     The knees-linking member  22 C is a second belt having a second predetermined width or a second cable having a second predetermined diameter; the present embodiment indicates an example in which the knees-linking member  22 C is the second belt. The knees-linking member  22 C is a bendable elongated member made of, for example, fabric. The one end side of the knees-linking member  22 C extends from the leg-side pulley  32 C and is looped around the left leg pulley  33 CL through a left guide portion  16 L provided in the left hip harness  7 L and connected to a linking member length adjustment device  37 C through a left guide portion  17 L. The other end side of the knees-linking member  22 C extends from the leg-side pulley  32 C and is looped around the right leg pulley  33 CR through a right guide portion  16 R provided in the right hip harness  7 R and connected to a fixing portion  37 CC of the waist harness  5  through a right guide portion  17 R. 
     The left guide portion  17 L guides the knees-linking member  22 C from the linking member length adjustment device  37 C toward the left leg pulley  33 CL and the left guide portion  16 L guides the knees-linking member  22 C from the left leg pulley  33 CL toward the leg-side pulley  32 C. Likewise, the right guide portion  17 R guides the knees-linking member  22 C from the fixing portion  37 CC toward the right leg pulley  33 CR and the right guide portion  16 R guides the knees-linking member  22 C from the right leg pulley  33 CR toward the leg-side pulley  32 C. 
     The one end of the knees-linking member  22 C is connected to a position in the waist harness  5 , the position being within the region from the waist region to the hip region and being in the vicinity of a left leg center axis LJ of the wearer as the wearer is viewed from the back side, (is connected to that position via the linking member length adjustment device  37 C). Also, the other end of the knees-linking member  22 C is connected to a position in the waist harness  5 , the position being within the region from the waist region to the hip region of the wearer and being in the vicinity of a right leg center axis RJ of the wearer as the wearer is viewed from the back side, (is connected to that position at the fixing portion  37 CC). Consequently, an acting force F 3 , which is illustrated in  FIG. 15 , can more effectively be obtained. 
     The linking member length adjustment device  37 C is provided in the waist harness  5  and the one end of the knees-linking member  22 C is connected to the linking member length adjustment device  37 C. The linking member length adjustment device  37 C can be set in either one of a released state in which winding and unwinding of the connected knees-linking member  22 C are possible and a locked state in which winding and unwinding of the connected knees-linking member  22 C are prohibited, enables a length of the knees-linking member  22 C (length of the W-shape from the left knee harness  9 L to the right knee harness  9 R) to be adjusted according to the physical size of the wearer and thus enables optimum (effective) transmission of an assist force. Also, a length adjustment device rotation axis  37 CJ, which is a rotation axis of the linking member length adjustment device  37 C, is set in a direction along a circumferential direction of the waist of the wearer. Note that the linking member length adjustment device  37 C may be omitted and the one end of the knees-linking member  22 C may be fixed to the waist harness  5 . 
     The left leg pulley  33 CL is a moving pulley, and a left linking member bend portion  22 CL bent so as to sag down is looped around the left leg pulley  33 CL between the one end (end portion connected to the linking member length adjustment device  37 C) of the knees-linking member  22 C and the leg-side pulley  32 C. Also, a left leg pulley rotation axis  33 CLJ, which is a rotation axis of the left leg pulley  33 CL, is set in the right-left direction of the wearer. Consequently, even if the knees-linking member  22 C comes into contact with the wearer, the area of the contact between the wearer and the knees-linking member  22 C can be made larger in comparison with the case where the left leg pulley rotation axis  33 CLJ is set in the front-rear direction of the wearer. 
     The right leg pulley  33 CR is a moving pulley, and a right linking member bend portion  22 CR bent so as to sag down is looped around the right leg pulley  33 CR between the other end (end portion connected to the fixing portion  37 CC) of the knees-linking member  22 C and the leg-side pulley  32 C. Also, a right leg pulley rotation axis  33 CRJ, which is a rotation axis of the right leg pulley  33 CR, is set in the right-left direction of the wearer. Consequently, even if the knees-linking member  22 C comes into contact with the wearer, the area of contact between the wearer and the knees-linking member  22 C can be made larger in comparison with the case where the right leg pulley rotation axis  33 CRJ is set in the front-rear direction of the wearer. 
     Since each of the left leg pulley  33 CL and the right leg pulley  33 CR is a moving pulley, the output torque of the electric motor  25 A may be half of a required torque, which is an assist force. Therefore, the electric motor  25 A can be made smaller, enabling reduction in size and weight. 
     The left knee harness  9 L and the left leg pulley  33 CL are connected via a belt  35 CL and a linking member  34 CL. Note that a length of the belt  35 CL is adjusted according to the physical size of the wearer. 
     The right knee harness  9 R and the right leg pulley  33 CR are connected via a belt  35 CR and a linking member  34 CR. Note that a length of the belt  35 CR is adjusted according to the physical size of the wearer. 
     Also, as illustrated in  FIG. 14 , disposing rollers  21 CC,  22 CC below the back torso-side pulley  31 C enables preventing the power transmission member  21 C and the knees-linking member  22 C from coming into contact with each other and thus is more preferable. 
     Also, disposing a guard panel P in an area, between the shoulder harness  3  and the waist harness  5 , in which the wearer&#39;s body is not covered and the power transmission member  21 C and the knees-linking member  22 C are likely to come into contact with the body prevents the wearer and the power transmission member  21 C and the knees-linking member  22 C from coming into contact with each other and thus is more preferable. 
     In comparison with the assist apparatus  1 A (see  FIG. 4 ) according to the first embodiment, in the assist apparatus  1 C (see  FIG. 15 ) according to the third embodiment, the position at which the electric motor  25 A is disposed is changed from the shoulder harness  3  to the waist harness  5 , enabling making the back side of the shoulder harness  3  simple. For example, where the wearer of the assist apparatus is a caregiver, when a care-receiver puts his/her hand around the back of the caregiver from the shoulder, the hand of the care-receiver is less likely to come into contact with foreign objects (various pulleys, etc.), which is more preferable. 
     Since the one end side of the single knees-linking member  22 C is looped around the left leg pulley  33 CL connected to the left knee harness  9 L and the other end side of the single knees-linking member  22 C is looped around the right leg pulley  33 CR connected to the right knee harness  9 R, when the wearer walks, the wearer can easily walk. More specifically, during walking, when the wearer swings the right leg forward and the left leg rearward, the knees-linking member  22 C is pulled up from the left leg side and is pulled out to the right leg side as viewed from the leg-side pulley  32 C. When the wearer swings the right leg rearward and the left leg forward, the knees-linking member  22  is pulled up from the right leg side and pulled out to the left leg side as viewed from the leg-side pulley  32 C. In other words, when the wearer walks, the knees-linking member  22 C looped around the leg-side pulley  32 C moves back and forth between the left leg side and the right leg side, and thus, the wearer can walk with almost no actuation of the actuator  25 , and thus, the wearer can walk easily (in this case, the leg-side pulley  32 C operates like a fixed pulley). 
     Next, a configuration of an assist apparatus  1 D according to a fourth embodiment will be described with reference to  FIG. 16 . Note that assist operations and processing in an ECU (control device) are similar to those of the first embodiment and thus description thereof will be omitted. 
     As illustrated in  FIG. 16 , in comparison with the assist apparatus  1 C according to the third embodiment illustrated in  FIG. 15 , in the assist apparatus  1 D according to the fourth embodiment, the power transmission member  21 C that is the first belt having the first predetermined width is changed to a power transmission member  21 D that is a first cable having a first predetermined diameter and the knees-linking member  22 C that is the second belt having the second predetermined width is changed to a knees-linking member  22 D that is a second cable having a second predetermined diameter. Along with the changes, a length adjustment device rotation axis  37 DJ, which is a rotation axis of a linking member length adjustment device  37 D is set not in a circumferential direction of the waist region of the wearer but in a horizontal direction orthogonal to the circumferential direction. Likewise, a back torso-side pulley rotation axis  31 DJ of a back torso-side pulley  31 D, a leg-side pulley rotation axis  32 DJ of a leg-side pulley  32 D, a left leg pulley rotation axis  33 DL) of a left leg pulley  33 DL and a right leg pulley rotation axis  33 DR) of a right leg pulley  33 DR are set not in a right-left direction but in a front-rear direction of the wearer. In addition, each of the motor pulley  25 BB, the linking member length adjustment device  37 D, the back torso-side pulley  31 D, the leg-side pulley  32 D, the left leg pulley  33 DL and the right leg pulley  33 DR is not a substantially columnar pulley but a pulley including a V groove. Also, the fourth embodiment is similar to the third embodiment in that the leg-side pulley  32 D, which is a fixed pulley, is connected to one end of the power transmission member  21 D via a pulley support portion  31 ZD. Also, a support  31 XD, a pulley support portion  31 YD, a fixing portion  37 DD of the fourth embodiment (see  FIG. 16 ) are similar to the support  31 XC, the pulley support portion  31 YC and the fixing portion  37 CC of the third embodiment (see  FIG. 15 ), respectively. 
     As a result of the above changes, the assist apparatus  1 D according to the fourth embodiment is further lighter relative to the assist apparatus  1 C according to the third embodiment (because of the change of the first belt and the second belt to the first cable and the second cable). Note that the power transmission member  21 C, the motor pulley  25 B and the back torso-side pulley  31 C of the assist apparatus  1 C according to the third embodiment illustrated in  FIG. 15  may be changed to the power transmission member  21 D, the motor pulley  25 BB and the back torso-side pulley  31 D illustrated in  FIG. 16  (it is possible that the power transmission member is the first cable and the knees-linking member is the second belt). Also, the knees-linking member  22 C, the leg-side pulley  32 C and the linking member length adjustment device  37 C of the assist apparatus  1 C according to the third embodiment illustrated in  FIG. 15  may be changed to the knees-linking member  22 D, the leg-side pulley  32 D and the linking member length adjustment device  37 D illustrated in  FIG. 16  (it is possible that the power transmission member is the first belt and the knees-linking member is the second belt). 
     It should be understood that the present disclosure is not limited to the above-described embodiments and various alterations, modifications, additions and deletions are possible without departing from the spirit of the present disclosure. Note that in the below description, reference numerals that are the same as those of components of the assist apparatus  1 A according to the first embodiment illustrated in  FIGS. 1 to 10  denote respective parts that are identical or correspond to the components or the like of the assist apparatus  1 A according to the first embodiment. 
     For example, a lower edge portion of a shoulder harness  3  and an upper edge portion of a part of a waist harness  5 , the part facing the back region, may be joined by a stretchable material such as mesh fabric. Also, respective lower edge portions of a left thigh fixing portion  12 L and a right thigh fixing portion  12 R of a left hip harness  7 L and a right hip harness  7 R and respective upper edge portions of a left knee harness  9 L and a right knee harness  9 R may be joined by a stretchable material such as mesh fabric. Consequently, the shoulder harness  3 , the waist harness  5 , the left hip harness  7 L and the right hip harness  7 R joined to the waist harness  5 , the left knee harness  9 L and the right knee harness  9 R can be joined to one another and thus integrated, enabling enhancement in ease of handling the assist apparatuses  1 A to  1 D. 
     Also, for example, respective left guide portions  16 L,  17 L and respective right guide portions  16 R,  17 R of the left hip harness  7 L and the right hip harness  7 R are not limited to those having a tubular shape but may be configured by sewing a ring-like loop at each of a plurality of positions so as to allow a knees-linking member  22 ,  22 B,  22 C,  22 D to be inserted therethrough. Consequently, the knees-linking member  22 ,  22 B,  22 C,  22 D can smoothly be guided. Also, the left guide portion  16 L,  17 L and the right guide portion  16 R,  17 R may be omitted. 
     Also, for example, for each of the power transmission member  21 ,  21 B,  21 C,  21 D and the knees-linking member  22 ,  22 B,  22 C,  22 D, any of various components such as a string or a belt fabricated by resin or fiber and a cable made of metal may be used. Note that, e.g., carbon-containing fibers are favorable materials because of high tensile strength.