Soft exosuit

Abstract

To provide a soft exosuit capable of supporting the whole walking motion.SOLUTION: Provided is a soft exosuit that includes: a wearable member that covers at least a portion of the waist, a portion of the knees, and a portion of the feet of a human body; a weight support member in which either one of an outer weight support member or an inner weight support member, or a set of two of an outer weight support member and an inner weight support member, is attached to each leg; and a control unit for controlling tension of the weight support member; wherein the outer weight support member has one end fixed to the foot portion of the wearable member, extends along the front shin portion through a point at the kneecap of the wearable member, and extends along the outer side of the thigh portion through a point on the back side of the waist of the wearable member to reach the control portion; and the inner weight support member has one end fixed to the foot portion of the wearable member, passes along the front shin to a point at the kneecap of the wearable member, and passes along the inner thigh to a point on the back side of the waist of the wearable member to reach the control portion.SELECTED DRAWING: Figure 1

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on U.S. Provisional Patent Application No. 63 / 594,190, filed on October 30, 2023, the contents of which are incorporated herein by reference. [Technical field]

[0002] The present invention relates to a soft exosuit that assists humans in walking. [Background technology]

[0003] Soft exosuits have been developed as powered assistive devices for people with walking disabilities (for example, Patent Documents 1 to 3). Unlike exoskeleton-type assist suits, soft exosuits are made of only soft materials such as cloth and wires, and have the advantage of being lightweight and highly comfortable to wear. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-073222 A [Patent Document 2] European Patent No. 3562458 [Patent Document 3] European Patent No. 2895133 Summary of the Invention [Problem to be solved by the invention]

[0005] However, to date, a soft exosuit capable of assisting the entire lower limbs throughout the entire walking motion, i.e., throughout the stance and swing phases, has not been realized. Common challenges facing soft exosuits include: Issue 1: Compared to exoskeleton-type walking assistance devices, the number of actuators increases, making control more complex. Problem 2: Feedback control is difficult. Challenge 3: It is difficult to achieve weight support while maintaining comfort.

[0006] One of the objectives of the present invention is to provide a soft exosuit that can support the entire lower limbs throughout the entire walking motion. [Means for solving the problem]

[0007] The soft exosuit of the present invention comprises a wearable member that covers at least a portion of the waist, a portion of the knees, and a portion of the feet of a human body; a weight support member in which either an outer weight support member or an inner weight support member is worn per leg, or a set of both the outer weight support member and the inner weight support member; and a control unit that controls the tension of the weight support members, one end of the outer weight support member is fixed to the foot part of the wearable member and passes along the front shin to a point on the kneecap of the wearable member and along the outside of the thigh to reach the control unit via a point on the back of the waist of the wearable member, and one end of the inner weight support member is fixed to the foot part of the wearable member and passes along the front shin to a point on the kneecap of the wearable member and along the inside of the thigh to reach the control unit via a point on the back of the waist of the wearable member. Effect of the Invention

[0008] The present invention makes it possible to provide a soft exosuit that can support the entire lower limbs throughout the entire walking movement. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an overall view of a soft exosuit 1 according to an embodiment of the invention. [Diagram 2] FIG. 1 shows the structure of an ankle joint of a soft exosuit 1 according to an embodiment of the invention. [Diagram 3] FIG. 1 shows the structure of wire 1 of a soft exosuit 1 in accordance with an embodiment of the invention. [Figure 4] FIG. 1 shows the structure of the wire 2 of the soft exosuit 1 in accordance with an embodiment of the invention. [Diagram 5] FIG. 2 is a diagram showing the structure of the wire 3 of the soft exosuit 1 in accordance with an embodiment of the invention. [Figure 6] FIG. 2 is a diagram explaining the function of the soft exosuit 1 in accordance with an embodiment of the invention. [Figure 7] FIG. 2 is a diagram explaining the function of the soft exosuit 1 in accordance with an embodiment of the invention. [Figure 8] FIG. 2 is a diagram showing the configuration of an actuation unit 50 of the soft exosuit 1 in accordance with an embodiment of the invention. [Figure 9] FIG. 1 is a diagram explaining a method for constructing control data for the amount of wire winding of the soft exosuit 1 in accordance with an embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] FIG. 1 is a diagram showing an overall view of a soft exosuit 1 according to an embodiment of the present invention. FIG. 2 is a diagram showing the structure of an ankle joint of the soft exosuit 1 according to an embodiment of the present invention. As shown in FIG. 1, the soft exosuit 1 includes wires 10, 20, and 30, a wearing part 40, and an actuation unit 50. The soft exosuit 1 is a walking assistance device worn by a person with walking disabilities, and assists walking movements by utilizing the tension of the wires 10, 20, and 30. The wires 10, 20, and 30 may be, for example, Bowden cables. The wires 10, 20, and 30 are disposed on the surface of a wearing part 40 (wearing member) that is directly worn on the human body as shown in FIG. 1. As shown in FIG. 2, one end of the wires 10, 20, and 30 is fixed to the foot part of the wearing part 40.

[0011] The actuation unit 50 (control unit) controls the tension (winding amount) of the wires 10, 20, and 30. The actuation unit 50 can move in accordance with the wearer's movement. The actuation unit 50 includes a motor as an actuator, and the driving force of the motor is transmitted to a pulley for winding the wires. Each wire is wound, thereby realizing assistance of the wearer's walking movement by each wire.

[0012] FIG. 3 is a diagram showing the structure of the wire 10 (body weight support member). As shown in FIG. 3, the wire 10 includes two wires, a wire 10a (outer body weight support member) and a wire 10b (inner body weight support member), for each leg. One end of the wire 10a is fixed to the foot of the wearing part 40, passes through a point 41 of the kneecap of the wearing part 40 along the front shin, and passes through a point 42 on the back side of the waist of the wearing part 40 along the outside of the thigh to reach the actuation unit 50. One end of the wire 10b is fixed to the foot of the wearing part 40, passes through a point 41 of the kneecap of the wearing part 40 along the front shin, and passes through a point 42 on the back side of the waist of the wearing part 40 along the inside of the thigh to reach the actuation unit 50.

[0013] The wire 10 has a function of applying a torque for supporting the body weight to the entire lower limb. The wires 10a and 10b are controlled by the same actuator. The wires 10a and 10b transmit the same torque to the hip joint, knee joint, and ankle joint in the sagittal plane direction. Specifically, the wire 10a applies an extension torque and an abduction restoring torque to the hip joint. That is, the wire 10a generates a restoring torque proportional to the tension of the wire 10a for restoring the adducted leg to the abduction direction. The wire 10b also applies an extension torque and an adduction restoring torque to the hip joint. That is, the wire 10b generates a restoring torque proportional to the tension of the wire 10b for restoring the abducted leg to the adduction direction. The wires 10a and 10b also apply an extension torque to the knee joint. The wires 10a and 10b also apply a torque in the direction opposite to the joint movement to the ankle joint, in the dorsiflexion direction during plantar flexion and in the plantar flexion direction during dorsiflexion.

[0014] The wire 10 can achieve the body weight support function even if only one of the wires 10a or 10b is attached to each leg. However, in order to prevent slippage on the body surface, it is desirable to attach the two wires 10a and 10b as a pair. Furthermore, with only the wire 10a, an adducted leg can be restored to the abduction direction, but an abducted leg cannot be restored to the adduction direction. Similarly, with only the wire 10b, an abducted leg can be restored to the adduction direction, but an abducted leg cannot be restored to the abduction direction. By attaching the two wires 10a and 10b as a pair, it is possible to handle both abduction and abduction.

[0015] FIG. 4 is a diagram showing the structure of the wire 20 (posture maintaining member). As shown in FIG. 4, the wire 20 includes two wires, a wire 20a (front posture maintaining member) and a wire 20b (rear posture maintaining member), for each leg. One end of the wire 20a is fixed to the foot of the wearing part 40, passes through a point 41 at the kneecap of the wearing part 40 along the front shin, passes through a point 43 on the ventral side of the waist of the wearing part 40 along the front side of the thigh, and reaches the actuation unit 50. One end of the wire 20b is fixed to the foot of the wearing part 40, passes through a point 44 behind the knee of the wearing part 40 along the calf, passes through a point 42 on the back side of the waist of the wearing part 40 along the back side of the thigh, and reaches the actuation unit 50.

[0016] The wire 20a does not necessarily need to span the entire four segments of the foot, the front shin (lower leg), the front thigh (thigh), and the ventral waist (trunk) (i.e., spanning the ankle, knee, and hip joints). If the wire 20a spans two joints of the ankle, knee, and hip joints, it has the effect of stabilizing the posture of the three segments including those two joints. For example, if the wire 20a spans the ankle and knee joints, it can stabilize the posture of the foot, lower leg, and thigh. Similarly, the wire 20b does not necessarily need to span the entire four segments of the foot, calf (lower leg), the back of the thigh (thigh), and the ventral waist (trunk), and if the wire 20b spans two joints of the ankle, knee, and hip joints, it has the effect of stabilizing the posture of the three segments including those two joints.

[0017] When the wire 20a spans three joints, the ankle joint, the knee joint, and the hip joint, in the stance phase, it transmits torque between the ankle joint dorsiflexion range of motion, the knee joint extension range of motion, and the hip joint flexion range of motion, and when one of the three joint ranges of motion is shortened, it functions to loosen the remaining two ranges of motion. Also, when the two ranges of motion are shortened, it functions to loosen the remaining one range of motion. Similarly, when the wire 20b spans three joints, the ankle joint, the knee joint, and the hip joint, in the stance phase, it transmits torque between the ankle joint plantar flexion range of motion, the knee joint flexion range of motion, and the hip joint extension range of motion, and when one of the three joint ranges of motion is shortened, it functions to loosen the remaining two ranges of motion. Also, when the two ranges of motion are shortened, it functions to loosen the remaining one range of motion. In this way, it is possible to stabilize the posture of four segments, including the ankle joint, the knee joint, and the hip joint, the foot, the lower leg, the thigh, and the trunk. For example, when crossing the ankle joint and knee joint, the posture of the three segments of the foot, lower leg, and thigh is stabilized, and when crossing the knee joint and hip joint, the posture of the three segments of the lower leg, thigh, and trunk is stabilized.

[0018] At the ankle joint, the assist torque by the wire 20 is prevented from changing depending on the angle of the joint. In order to prevent the moment arm, which is the distance between the wire 20 and the center of the joint, from changing depending on the joint angle, a non-elastic belt 45 is provided at the ankle joint of the wearing part 40 as shown in FIG. 2, and one end of each wire is fixed. The non-elastic belt 45 is connected to the wire 20 extending from the lower leg part through a path in which the moment arm is constant from the sole to the left and right of the foot in both the dorsiflexion direction and the plantar flexion direction. This makes it possible to prevent compression force from being applied to the skin of the foot except when assisting. At the knee joint, the moment arms of both the front wire 20a and the rear wire 20b can be adjusted. The distance between the knee pad 46 and the outer cable that functions as a pulley of the wire 20a can be adjusted by the screw 47. As for the wire 20b, the moment arm during assisting can be adjusted by adjusting the length of the non-elastic belt between the outer cable that functions as a pulley and the knee pad.

[0019] Fig. 5 is a diagram showing the structure of the wire 30 (swing leg assist member). As shown in Fig. 5, the wire 30 includes two wires, 30a (outer swing leg assist member) and 30b (inner swing leg assist member), for each leg. One end of the wire 30a is fixed to the foot of the wearing part 40, and reaches the actuation unit 50 via a point 43 on the ventral side of the waist of the wearing part 40 along the outer side of the leg. One end of the wire 30b is fixed to the foot of the wearing part 40, and reaches the actuation unit 50 via a point 43 on the ventral side of the waist of the wearing part 40 along the inner side of the leg.

[0020] The wire 30 assists the swinging motion of the swing leg in the swing phase, and for the hip joint, the wire 30a transmits a flexion torque and a torque to restore the adducted leg in the abduction direction, and the wire 30b transmits a flexion torque and a torque to restore the abducted leg in the adduction direction. It transmits a flexion torque to the knee joint and a dorsiflexion torque to the ankle joint. During the swing phase, the wires 10 and 20 acting during the stance phase are loosened, and the wire 30 drives the assist of the swinging motion of the hip joint, knee joint, and ankle joint. At the hip joint, a flexion torque is applied to swing the swing leg forward. At the knee joint and ankle joint, a torque is applied to flex the knee joint and dorsiflex the ankle joint to ensure clearance between the sole of the foot and the floor. Compared to the wires 10 and 20, the tension required for the assist by the wire 30 is smaller, but a faster winding speed is required.

[0021] The wire 30 can achieve the swing leg assist function even if only one of the wires 30a or 30b is attached to each leg. However, in order to prevent slippage on the body surface, it is desirable to attach the two wires 30a and 30b as a pair. Furthermore, with only the wire 30a, an adducted leg can be restored to the abduction direction, but an abducted leg cannot be restored to the adduction direction. Similarly, with only the wire 30b, an abducted leg can be restored to the adduction direction, but an abducted leg cannot be restored to the abduction direction. By attaching the two wires 30a and 30b as a pair, it is possible to respond to both abduction and abduction.

[0022] The wearing part 40 is formed of an elastic fabric such as a wetsuit, and a non-elastic belt such as a PP (polypropylene) band may be attached to the waist part. This makes it possible to suppress shear force and floating on the body surface generated when assisted by the wires while maintaining comfort when worn. Each wire is formed of, for example, a Bowden cable, which is composed of an outer cable and an inner wire. A structure that exerts an anti-gravity function can be realized by adhering the outer cable to the fabric of the wearing part 40 with an adhesive with excellent compressive stress properties and a thread with excellent tensile properties.

[0023] By arranging a non-elastic belt around the waist of the wearing part 40, it is possible to suppress the shear force applied to the thigh and lower leg due to deformation of the outer cable. In particular, in the case of the wire 10, which is subjected to a large force, the shear force is structurally offset by arranging the two wires in parallel at the thigh. In addition, a knee pad 46 may be provided at the knee part, and a mechanism (screw 47) capable of adjusting the moment arm may be attached to the knee pad 46.

[0024] Next, the functions of the soft exosuit 1 according to this embodiment will be described. First, the function of controlling posture during the stance phase will be described with reference to Figures 6 and 7. When assisting the standing up movement, the function of the wire 20 changes as follows according to the distribution of hip joint extension and knee joint extension torque by the wire 10. i) When the knee joint extension torque is excessive Increasing the tension in wire 20b inhibits knee joint extension and increases hip joint extension torque. ii) When the hip extension torque is excessive Increasing the tension of the wire 20a inhibits hip joint extension and promotes knee joint extension.

[0025] In particular, when landing on the ground, if only the wire 10 functions, the hip joint is extended and the knee joint is bent, and the trunk is leaning backward, as shown in Fig. 7. This is because, if the displacement of the wire 10 is constant, the lower the trunk position is, the smaller the potential energy becomes, resulting in a stable state. According to this embodiment, the wire 20 functions in addition to the wire 10, and the trunk can be kept in an upright position.

[0026] (Wire winding control) FIG. 8 is a diagram showing the configuration of the actuation unit 50 of the soft exosuit 1 according to this embodiment. As shown in FIG. 8, the actuation unit 50 includes a motor control unit 51, a motor 52, and a pulley 53. The actuation unit 50 controls the winding of the wires 10 to 30 by feedforward control. For example, the actuation unit 50 may be configured such that the motor control unit 51, the motor 52, and the pulley 53 are mounted on a wheeled housing connected to the wearing part 40 via the wires 10 to 30, and the housing may be moved by being pulled by the wires 10 to 30 in accordance with the wearer's movements. The method of moving the housing is not limited to this, and for example, the wearer may move the housing while pushing it with his or her hands, or the actuation unit 50 may be mounted on a walker or the like. In addition, an assistant may move the housing in accordance with the wearer's movements.

[0027] The motor 52 may be, for example, a stepping motor. However, the motor 52 is not limited to a stepping motor as long as the motor has accurate control of the winding amount and good torque-rotation speed characteristics. The driving force of the motor 52 is transmitted to the wires 10 to 30 via a pulley 53. The wires 10 to 30 may be Bowden cables composed of an outer cable and an inner wire, and the motor 52 can transmit the assist torque even if it is separated from the wearer's joints. The motor 52 may include a motor that winds up the wires 10a and 10b, a motor that winds up the wire 20a, a motor that winds up the wire 20b, and a motor that winds up the wires 30a and 30b.

[0028] The motor control unit 51 may be configured as a general-purpose computer including a processor, a memory, an input / output interface, a communication interface, and a storage device. The storage device of the motor control unit 51 stores control data for each motor, and the processor drives the motor via the driver for each motor based on the control data. The control data may be constructed based on data on the walking movement of an able-bodied person.

[0029] FIG. 9(A) is a diagram showing an example of motor control data according to this embodiment. In the graph of FIG. 9(A), the wires are wound up as they move upward on the vertical axis. The construction process of the control data shown in FIG. 9(A) will be described. First, the data shown in FIG. 9(B) was calculated based on the data normalized over one walking period for the time changes in the joint angles of the hip joint, knee joint, and ankle joint, using motion capture data when an able-bodied person walked while wearing the soft exosuit 1. In the example of FIG. 9(B), the right foot starts the movement from the initial swing posture and the left foot starts the movement from the loading response posture, so in FIG. 9(B), the time when the left foot makes initial contact is set to 0.

[0030] In the soft exosuit 1, only the wire 30 is driven during the swing phase, and the wires 10 and 20 are driven during the stance phase. Therefore, the wires 10 and 20 during the swing phase, and the wire 30 during the stance phase were corrected to be in a slack state with zero tension. Through the above process, the motor control data shown in Figure 9(A) was constructed. Note that Figure 9(A) shows that the initial swing phase of the right foot begins immediately after the wire 30 of the right foot starts to wind up.

[0031] As described above, the soft exosuit 1 according to this embodiment can assist the entire lower limbs and the posture of the lower trunk during the stance and swing phases of walking without complex feedback control. The wire 10 provides the torque required for the hip joint, knee joint, and ankle joint to support the body weight. Furthermore, it has the function of mechanically controlling the direction of the floor reaction force according to the posture of the lower limbs. For example, in the initial stance posture, the output of the wire 10 contains many vertical components, whereas in the middle to late stance phase, the output of the wire 10 is dominated by propulsion components. In this way, the assist torque can be mechanically adjusted according to the posture of the lower limbs without relying on feedback control.

[0032] In addition, the wire 20 transmits torque between the joints it straddles, and mechanically adjusts the posture of the lower limbs and the direction of the floor reaction force without relying on feedback control. For example, if the knee tries to bend excessively during the stance phase, the wire 20 increases the tension, automatically suppressing the bending of the knee. At this time, the increased tension of the wire 20 does not cause the hip joint or ankle joint to receive torque that would cause it to deviate from a healthy posture.

[0033] Moreover, the wire 30 applies hip flexion, knee flexion, and ankle dorsiflexion torque during the swing phase. The wire 30 assists the knee joint and ankle joint so as to ensure clearance between the sole of the foot and the ground, and exerts torque to swing the swing leg forward by flexing the hip joint. A stopper may be attached to the knee portion of the wire 30 to prevent applying more torque than necessary to the knee joint and ankle joint. In order to increase the walking speed, it is necessary to increase the motor output to increase the hip joint flexion torque, but at that time, the proportion of assistance to the hip joint flexion can be increased by limiting the assistance to the knee joint and ankle joint.

[0034] According to this embodiment, the wire 10 and the wire 30 are structured such that the wire that applies the same torque is branched into two. This makes it possible to prevent the wire from slipping on the body surface. Slipping on the body surface occurs when a force that tends to deform the outer cable of the wire into a straight line is applied during assistance when the layout is such that the drive position of the wire switches between the front and rear of the body at adjacent joints among the hip joint, the knee joint, and the ankle joint. According to this embodiment, the wires 10 and 30 of one leg are symmetrical in shape, and the left and right outer cables are connected with a non-elastic material, so that the force that tends to deform the outer cable into a straight line can be offset by the left and right cables.

[0035] In addition, based on data on the walking motion of able-bodied people, the amount of winding of each wire is feedforward controlled to reproduce the walking motion of able-bodied people, making it possible to realize appropriate assistance for walking motion without performing complex feedback control.

[0036] In addition, in this embodiment, the entire walking motion is assisted by the wires 10 to 30, but the same function can be achieved by using members other than the wires 10 to 30. For example, artificial muscles or springs may be used instead of the wires.

[0037] It should be noted that the present invention is not limited to the above-described embodiment, and can be embodied in various other forms without departing from the spirit and scope of the present invention. Therefore, the above-described embodiment is merely illustrative in all respects and should not be interpreted as being restrictive. [Explanation of symbols]

[0038] 1...Soft exosuit, 10, 20, 30...Wires, 40...Wearing part, 41 to 44...Points, 45...Non-elastic belt, 46...Knee pad, 47...Screw, 50...Actuation unit, 51...Motor control unit, 52...Motor, 53...Pulley

Claims

1. A wearing member that covers at least a part of a waist, a part of a knee, and a part of a foot of a human body; A weight support member in which either one of an outer weight support member or an inner weight support member, or a set of the outer weight support member and the inner weight support member, is attached to each leg; A control unit that controls the tension of the body weight support member, The outer weight support member is One end is fixed to the foot portion of the wearing member, passes through a point at the kneecap of the wearing member along the front shin portion, passes through a point on the back side of the waist portion of the wearing member along the outer side of the thigh, and reaches the control portion; The inner weight support member is One end is fixed to the foot portion of the wearing member, passes through a point at the kneecap of the wearing member along the front shin portion, and passes through a point on the back side of the waist portion of the wearing member along the inner side of the thigh, and reaches the control portion. Soft exosuit.

2. a pair of posture maintaining members, a front posture maintaining member and a rear posture maintaining member, are attached to each leg; The control unit controls the tension of the attitude maintaining member, The front attitude maintaining member is It is attached along the front of the leg, spanning two or three joints among the ankle joint, knee joint, and hip joint, The rear attitude maintaining member is It is worn along the back of the leg, spanning two or three joints among the ankle, knee, and hip joints. The soft exosuit of claim 1.

3. For each leg, a swing leg auxiliary member is provided, which is either an outer swing leg auxiliary member or an inner swing leg auxiliary member, or a pair of the outer swing leg auxiliary member and the inner swing leg auxiliary member, The control unit controls the tension of the swing leg assist member, The outer swing leg assist member is One end is fixed to the foot portion of the wearable member, and the other end extends along the lateral side of the leg to a point on the ventral side of the waist portion of the wearable member, and the other end extends to the control portion; The inner swing leg assist member is One end is fixed to the foot portion of the wearable member, and the other end extends along the inside of the leg to a point on the ventral side of the waist portion of the wearable member, and reaches the control portion.

3. The soft exosuit according to claim 1 or 2.

4. The body weight support member is The hips, knees, and ankles transmit the torque required to support the body weight. The outer weight support member is Transmits an extension torque to the hip joint and a torque to restore the adducted leg in the abduction direction, transmits an extension torque to the knee joint, and transmits a torque in the opposite direction to the joint movement to the ankle joint. The inner weight support member is Transmits an extension torque and a torque to restore the abducted leg in the adduction direction to the hip joint, transmits an extension torque to the knee joint, and transmits a torque in the opposite direction to the joint movement to the ankle joint. The soft exosuit of claim 1.

5. The posture maintaining member is Controls the forward / backward tilt of posture during stance phase, When worn across the ankle joint and knee joint, it stabilizes the posture of the foot, lower leg, and thigh; when worn across the knee joint and hip joint, it stabilizes the posture of the lower leg, thigh, and trunk; when worn across the ankle joint, knee joint, and hip joint, it stabilizes the posture of the foot, lower leg, thigh, and trunk; The soft exosuit of claim 2.

6. The swing leg assist member is Assists the swing leg's swing motion during the swing phase, The outer swing leg assist member is Transmits a flexion torque and a torque to restore the adducted leg to the abduction direction to the hip joint, transmits a flexion torque to the knee joint, and transmits a dorsiflexion torque to the ankle joint; The inner swing leg assist member is Transmits a flexion torque and a torque to restore the abducted leg to the adduction direction to the hip joint, transmits a flexion torque to the knee joint, and transmits a dorsiflexion torque to the ankle joint. The soft exosuit of claim 3.

7. The control unit is The soft exosuit of claim 1 , wherein tension is controlled to replicate normal gait.

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