Patent Publication Number: US-2023137939-A1

Title: Personal Augmentation Suit and Method for Assisted Human Motion with Back Differential Assembly

Description:
CLAIM TO DOMESTIC PRIORITY 
     The present application is a continuation of U.S. patent application Ser. No. 16/801,341, filed Feb. 26, 2020, which claims the benefit of U.S. Provisional Application No. 62/811,447, filed Feb. 27, 2019, which applications are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates in general to a human assistance device, and more particularly, to a personal augmentation suit and method for assisted human motion with a differential assembly on the back of the suit. 
     BACKGROUND OF THE INVENTION 
     A variety of human assistance devices provide aid for human motion. Some work tasks and activities demand frequent and heavy lifting or long-term strenuous movement, beyond normal unassisted physical exertion, and can lead to exhaustion and potential injury. In particular, excessive strain on muscles and joints can cause injury to the back, legs, and knees with associated reduction in productivity. The human assistance device as worn by the user is designed to overcome or compensate for the added load or strain and make many work tasks easier to perform. 
     In one embodiment, the human assistance device uses an exoskeleton with rigid components e.g., linkages and joints, attached to the user&#39;s body. The exoskeleton joints are positioned to have an axis of rotation collinear with a natural axis of rotation for adjacent joints. The rigid exoskeleton relies on a framework of linkages connected to the body at select locations via pads and straps to provide the ability to augment human movements that need assistance or otherwise enhance the user&#39;s performance, stability, balance, and safety. As the user flexes or extends his limbs, these rigid links move in parallel with the limb, adding considerable inertia to the movement. Unfortunately, the rigid exoskeleton also causes considerable restriction to the user&#39;s motion that impedes natural and fluid movement. 
     In another example, U.S. patent publication 2015/0321339 discloses a soft exosuit that generates forces about one or more joints based on anchor elements and connection elements disposed between the anchor elements. The exosuit uses sensors to determine forces on the anchor or connection elements. Actuators are configured to change tension in the soft exosuit in response to the sensors. The exosuit tends to be complex with an overreliance on active components, such as sensors and actuators, to control its operation. The intricate interconnection of anchor elements, connection elements, sensors, and actuators tend to be expensive to manufacture, difficult to configure, slow in response, and overall low reliability. 
     The soft exosuit can be worn for long periods of time. The user typically performs a variety of functions while wearing the exosuit, including crouching, lifting, and walking. During gait, the movement of the legs tends to stretch the exosuit and impart resistance on the user, even when not in a lifting action. The resistance caused by gait can be uncomfortable for the user, particularly when wearing the exosuit for long periods of time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS.  1   a - 1   c    illustrate a user wearing a passive P2K suit; 
         FIG.  2    illustrates the passive P2K suit with the split knee pads and angle straps in the open position; 
         FIGS.  3   a - 3   c    illustrate the passive P2K suit activated to assist with lifting a load; 
         FIG.  4    illustrates further detail of the torso harness with a differential assembly; 
         FIGS.  5   a - 5   c    illustrate the differential assembly during a lift and gait; 
         FIGS.  6   a - 6   c    illustrate the differential assembly implemented with a lever arm; 
         FIG.  7    illustrates the differential assembly implemented with a pulley; 
         FIG.  8    illustrates the differential assembly implemented with gears; 
         FIG.  9    illustrates the differential assembly implemented with a tube; and 
         FIGS.  10   a - 10   c    illustrate the passive P2K suit with the differential assembly and buckles around the leg straps. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The present invention is described in one or more embodiments in the following description with reference to the figures, in which like numerals represent the same or similar elements. While the invention is described in terms of the best mode for achieving the invention&#39;s objectives, those skilled in the art will appreciate that the description is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims and their equivalents as supported by the following disclosure and drawings. 
       FIG.  1   a    shows user  100  wearing potential to kinetic suit (P2K)  102  suitable for human assistance in crouching, kneeling, squatting, and lifting under load, as well as normal gait without resistance or discomfort. P2K  102  is a passive personal augmentation suit or strapping system, i.e., no active components, applicable to many types of human activity and physical work, such as moving heavy articles, up and down motion under load, and other repetitive, long-term physical exertion. P2K  102  is capable of storing potential energy in the strapping arrangement, e.g., potential energy is stored in elastic strapping when transitioning from a standing position to a crouched, kneeling, squatting, or seated position. The potential energy in P2K  102  is released when user  100  returns upright in stance, thereby assisting the user in the motion, particularly while under load. P2K  102  increases endurance, reduces fatigue, and decreases potential for injury associated with such activity, particularly for the user&#39;s back, legs, and knees. P2K  102  includes an interconnected arrangement of straps, belts, and braces to provide passively loaded support and reaction for user  100 , while assisting with human motion under load. P2K  102  further includes a back-mounted differential assembly to enable normal gait for user  100 , without resistance or discomfort from the suit.  FIG.  1 B  shows a side view of P2K  102 ;  FIG.  1   c    shows a back view of P2K  102 . Portions of P2K  102  can be reflective material for safety. 
     Upper torso harness  110  includes backpack assembly  112  with shoulder straps  114  and upper back straps  116 . Backpack assembly  112  can include a combination of durable materials such as textured nylon, polyurethane coated polyester, and rigid plastic or polymer inserts, as well as elastic material and webbing material. Backpack assembly  112  can be made with an air mesh material with openings to allow for airflow on the back and reduce the overall weight. Backpack assembly  112  covers a portion of the back area of user  100  to improve ergonomics and comfort, relieve lower back pressure, and ease of donning and doffing. Shoulder straps  114  extend over the shoulder and affix to backpack assembly  112  with sewing, rivets, belt, buckles, buttons, snaps, hooks, adhesive, Velcro®, or other secure attachment mechanism. Shoulder straps  114  are made with elastic material or webbing material and can slide, loosen, or tighten relative to backpack assembly  112  for user comfort and adapting to movement. Buckle  117  in shoulder straps  114  provides adjustment and attachment points. Buckle  117  snaps to lock and enable P2K  102  to fit different body sizes. 
     Backpack assembly  112  includes differential assembly  118  to enable normal gait activity for user  100 , without resistance or discomfort from P2K  102 , discussed further infra. Upper back straps  116  continue from shoulder straps  114  to an upper portion of differential assembly  118 . Lower back straps  120  extends over the gluteal area and connects to differential assembly  118  with sewing, rivets, belt, buckles, buttons, snaps, hooks, adhesive, Velcro®, or other secure attachment mechanism. Lower back straps  120  slides or moves relative to backpack assembly  112  to enable or minimize medial/lateral relative motion and provide pre-tensioning. Shoulder straps  114  anchor to backpack assembly  112 , and side straps  122  extend from backpack assembly  112  under the arms and along the side torso above the hip of user  100  to backpack assembly  112  or lower back straps  120 . Side straps  122  can include elastic material with buckles  124  for adjustments and comfort. 
     Leg strap arrangement  128  extends down the legs of user  100 . Leg straps  128  include hamstring portion  128   a  (continuation of lower back straps  120 ) over the hamstrings of user  100 , knee portion  128   b  over the front of the knee area, and calf portion  128   c  over the calf area. Hamstring portion  128   a  connects to lower back straps  120   a  (left side) and  120   b  (right side) with sewing, rivets, belt, buckles, buttons, snaps, hooks, adhesive, Velcro®, or other secure attachment mechanism. Seat strap or webbing  126  is connected to lower back straps  120   a - 120   b  with sewing, rivets, belt, buckles, buttons, snaps, hooks, adhesive, Velcro®, or other secure attachment mechanism. Seat strap  126  is an elastic or webbing material for storing and releasing power and comfortable load distribution. Knee portion  128   b  includes knee pads  130  for padding and protection of the knee while kneeling on the ground. Knee portion  128 B provides an anchor point during energy storage and return while using P2K  102 . In particular, knee pad  130  opens or splits along vertical or angled seam  132  and closes with buttons, snaps, hooks, Velcro®, or other secure attachment mechanism for ease of donning and doffing P2K  102 . Leg straps  128  utilize the bending motion of the knee for maximum stretching of the elastic bands. Calf portion  128   c  includes strap  136  extending down the tibia and strap cuff  138  over the calf. Strap  138  closes with buttons, hooks, snaps, Velcro®, cuff, or other secure attachment mechanism.  FIG.  1   a    shows knee pad  130  and strap cuff  138  in the closed position.  FIG.  2    shows knee pad  130  and strap cuff  138  in the open position. The combination of shoulder strap buckle  117 , split knee pads  130 , and calf strap cuff  138  provide for ease of donning and doffing P2K  102 . 
     The various straps and belts in  FIGS.  1   a - 1   c    can be implemented using fabric or leather material, elastic bands, cables, or other suitable flexible connecting members. P2K  102  stores potential energy in the strapping arrangement, e.g., the elastic strapping stretches and stores potential energy when transitioning from a standing position to a crouched, squatting, or seated position. The potential energy in P2K  102  remains available while user  100  is seated to help with the opposing motion, i.e., standing up under load. When user  100  stands up from the seated position under load, the potential energy in P2K  102  is released to assist the user in the upward motion. P2K  102  reduces the effort, strain, fatigue, and potential for injury associated with such movement in physical labor work environments. 
     Consider user  100  wearing P2K  102  in a crouching or kneeling position to pick up load  144  in  FIGS.  3   a - 3   b   . P2K  102  stores potential energy in the strapping arrangement, e.g., the elastic strapping stretches and stores potential energy when transitioning from a standing position to a crouching, kneeling, or seated position. The potential energy in P2K  102  remains available while user  100  is crouching to help with the opposing motion, i.e., standing up under load  144 . User  100  stands up from the crouching position with load  144  in  FIG.  3   c   . The potential energy in P2K  102  is released when user  100  moves from the crouching, kneeling, or seated position to return upright in stance, thereby assisting the user in the motion, particularly while under load. P2K  102  reduces the effort, strain, fatigue, and potential for injury associated with such movement in physical labor work environments. In one embodiment, knee pad  130  includes a torsional spring to aid with transition from a seated, kneeling, or crouched position to a standing position, without the use of active components. Alternatively, knee pad  130  uses elastic bands, or a combination of non-elastic and elastic bands, to assist user  100  in the sit to stand transition. 
       FIG.  4    illustrates another view of a portion of P2K  102  as upper torso harness  110 , and in particular with differential assembly  118  connected to upper back straps  116  along horizontal bar  150  and left lower back strap  120   a  and right lower back strap  120   b  along horizontal bar  160 . In this embodiment, differential assembly  118  is configured as an x-bar to provide support, stretch, and resistance when legs are moved together (crouch and lift), and free motion when legs are moved opposite or independently (gait). When user  100  squats or bends at the waist or knees, the straps of P2K  102  are lengthened. P2K  102  provides assistance by resisting the squatting or bending motions in that straps are on the side of the joint (knee or hip) that lengthens when the joint goes from straight to a bent position. In particular, x-bar type differential assembly  118  includes horizontal bar  150  secured to upper back straps  116  or backpack assembly  112  with anchor  152 , as shown in  FIG.  5   a   . Strings or cables  154  and  156  are anchored to bar  150  at points  158   a  and  158   b  to make the x-bar. Cables  154  and  156  are routed to horizontal bar  160  and around revolute joints  162   a  and  162   b  to anchor  164 . Horizontal bar  160  is secured to lower back straps  120   a - 120   b  at revolute joints  166   a  and  166   b.    
     Differential assembly  118  allows the independent or opposite motion of the left and right lower back straps  120   a - 120   b , i.e., during normal gait activity, but does not allow motion through the differential assembly of the left lower back strap  120   a  and right lower back strap  120   b  in the same direction, i.e., while squatting or lifting. In other words, differential assembly  118  shifts or tilts in position for opposite motion of the left and right lower back straps  120   a - 120   b  (gait), and is held in place by symmetric loading when the right leg and left leg both move up or down together in the same direction with respect to anchor  152  (squat or lift). If the left and right lower back straps  120   a - 120   b  move up or down together, e.g., in squatting or lifting motion, then a motion and force is transmitted through differential assembly  118  to stretch P2K  102  for the human motion assistance, as described above and shown in  FIG.  5     a.    
     During a first phase of gait, the left leg reaches out and pulls down on the left lower back strap  120   a  while the right leg lags allowing the right lower back strap  120   b  to go up, as shown in  FIG.  5   b   . In a second phase of gait, the right leg reaches out and pulls down on the right lower back strap  120   b  while the left leg lags allowing the left lower back strap  120   a  to go up, as shown in  FIG.  5   c   . It is preferable to not activate or stretch P2K  102  during gait, which induces unnecessary resistance and would be uncomfortable to user  100 . Differential assembly  118  achieves this purpose by allowing the left lower back strap  120   a  to move down while the right lower back strap  120   b  moves up, as in  FIG.  5   b   , or the left lower back strap  120   a  to move up while the right lower back strap  120   b  moves down, as in  FIG.  5   c   , without activating or stretching P2K  102 . When the right or left lower back strap  120   a - 120   b  is moved independently or in opposite directions, force is not transmitted through differential assembly  118  to anchor  152 . The relative amount of motion between the left and right lower back strap  120   a - 120   b  through differential assembly  118  can be the same, i.e., the right moves up by distance D 1  and the left moves down by the same distance D 1 . If differently proportioned, the right moves up by distance D 1  and the left moves down by distance D 2  different from D 1 , or one side can move while the other remains stationary. Accordingly, differential assembly  118  reduces resistance from the stretching of P2K  102  while walking, which would be uncomfortable to user  100 . 
     Differential assembly  118  can be implemented using a variety of embodiments. In  FIG.  6   a   , differential assembly  118  is implemented as lever arm  170 , which is attached to upper back straps  116  at revolute joint  172 , left lower back strap  120   a  at revolute joint  174 , and right lower back strap  120   b  at revolute joint  176 . If the left and right lower back strap  120   a - 120   b  move up or down together, e.g., crouch to lift, then lever arm  170  remains level (does not pivot or rotate) and the motion is transferred through the lever arm to stretch P2K  102  for the human motion assistance described above. During gait, when the left lower back strap  120   a  moves down and the right lower back strap  120   b  moves up, then lever arm  170  rotates about revolute joints  172 ,  174 , and  176 , see  FIG.  6   b   . The left side of lever arm  170  moves down with the left lower back strap  120   a , and the right side of lever arm  170  moves up with the right lower back strap  120   b . When the left lower back strap  120   a  moves up and the right lower back strap  120   b  moves down, then lever arm  170  rotates about revolute joints  172 ,  174 , and  176 , see  FIG.  6   c   . The left side of lever arm  170  moves up with the left lower back strap  120   a , and the right side of lever arm  170  moves down with the right lower back strap  120   b.    
     In  FIG.  7   , differential assembly  118  is implemented as pulley  180 , which is attached to upper back straps  116  at revolute joint  182 . Cable  184  is routed over pulley  180  and attached to the left lower back strap  120   a  and right lower back strap  120   b . If the left and right lower back strap  120   a - 120   b  move up or down together, e.g., crouching to lift, the motion is transferred through pulley  180  (left side of cable  184  does not move relative to the right side of the cable) to stretch P2K  102  for the human motion assistance. During gait, when the left lower back strap  120   a  moves down and the right lower back strap  120   b  moves up, then pulley  180  and cable  184  rotate about revolute joint  182 . The left side of cable  184  moves down with the left lower back strap  120   a , and the right side of cable  184  moves up with the right lower back strap  120   b . When the left lower back strap  120   a  moves up and the right lower back strap  120   b  moves down, then pulley  180  and cable  184  rotate about revolute joint  182 . The left side of cable  184  moves up with the left lower back strap  120   a , and the right side of cable  184  moves down with the right lower back strap  120   b.    
     In  FIG.  8   , differential assembly  118  is implemented as gear system  200 , which uses gears  202 ,  204 , and  206  attached to upper back straps  116  at revolute joints  208 ,  210 , and  212 , respectively. Cable  216  is routed over gear  202 , under gear  206 , and over gear  204 , and attached to the left lower back strap  120   a  and right lower back strap  120   b . If the left and right lower back strap  120   a - 120   b  move up or down together, e.g., squatting to lift, the motion is transferred through gear system  200  (left side of cable  216  does not move relative to the right side of the cable) to stretch P2K  102  for the human motion assistance. During gait, when the left lower back strap  120   a  moves down and the right lower back strap  120   b  moves up, then gears  202 - 206  and cable  216  rotate about revolute joints  208 - 212 . The left side of cable  216  moves down with the left lower back strap  120   a , and the right side of cable  216  moves up with the right lower back strap  120   b . When the left lower back strap  120   a  moves up and the right lower back strap  120   b  moves down, then gears  202 - 206  and cable  216  rotate about revolute joints  208 - 212 . The left side of cable  216  moves up with the left lower back strap  120   a , and the right side of cable  216  moves down with the right lower back strap  120   b.    
     In  FIG.  9   , differential assembly  118  is implemented as channel or tube  220 , which is attached to upper back straps  116 . Cable  224  is routed through tube  220  and attached to the left lower back strap  120   a  and right lower back strap  120   b . If the left and right lower back strap  120   a - 120   b  move up or down together, e.g., squatting to lift, the motion is transferred through tube  220  (left side of cable  224  does not move relative to the right side of the cable) to stretch P2K  102  for the human motion assistance. During gait, when the left lower back strap  120   a  moves down and the right lower back strap  120   b  moves up, then cable  224  moves through tube  220  to the left. The left side of cable  184  moves down with the left lower back strap  120   a , and the right side of cable  184  moves up with the right lower back strap  120   b . When the left lower back strap  120   a  moves up and the right lower back strap  120   b  moves down, then cable  224  moves through tube  220  to the right. The left side of cable  184  moves up with the left lower back strap  120   a , and the right side of cable  184  moves down with the right lower back strap  120   b.    
       FIG.  10   a    shown an embodiment with x-bar differential assembly  230  and buckles  232  around leg straps  128 . In this case, lower back strap  120   a  is connected to right side of bar  234  and lower back strap  120   b  is connected to the left side of bar  234 . Buckles  232  are described in U.S. patent application Ser. No. 16/655,221, entitled Preloaded Personal Augmentation Suit and method for Assisted Human Motion, which is incorporated herein by reference.  FIGS.  10   b - 10   c    shows differential assembly  230  during gait, similar to  FIGS.  5   b - 5   c   . If the left and right lower back strap  120   a - 120   b  move up or down together, e.g., squatting to lift, the motion is transferred through differential assembly  230  to stretch P2K  102  for the human motion assistance. During gait, when the left lower back strap  120   a  moves down and the right lower back strap  120   b  moves up, then the right side of bar  234  moves down with the left lower back strap  120   a , and the left side of bar  234  moves up with the right lower back strap  120   b , see  FIG.  10   b   . When the left lower back strap  120   a  moves up and the right lower back strap  120   b  moves down, then the right side of bar  2348  moves up with the left lower back strap  120   a , and the left side of bar  234  moves down with the right lower back strap  120   b , see  FIG.  10     c.    
     While one or more embodiments of the present invention have been illustrated in detail, the skilled artisan will appreciate that modifications and adaptations to those embodiments may be made without departing from the scope of the present invention as set forth in the following claims.