Gait improvement device and gait improvement method

Abstract

To reduce the risk of falls.SOLUTION: A gait improvement device 100 is wearable on an object person in a sitting posture who is an object of gait improvement. A rhythm generator 110 is capable of generating a periodical first rhythm RY1. A rhythm detector 120 detects a second rhythm RY2 being an arm swinging rhythm of the object person while the object person performs an arm swinging exercise in a sitting posture. A rhythm synchronizer 130 adjusts the rhythm generator 110 in such a manner that the first rhythm RY1 synchronizes to the second rhythm RY2. A drive part 140 applies rhythm stimulation corresponding to the first rhythm RY1 to the object person in such a manner that the second rhythm RY2 synchronizes to the first rhythm RY1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a technique for improving human walking motion.

Background Art

[0002] In order to assist the walking motion of the elderly, disabled, or injured persons who have difficulty in walking, or to improve it through rehabilitation, a walking improvement device is used. Conventionally, as a method for assisting and improving walking, there has been a method of directly assisting lower limb movement. Specifically, a method has been proposed in which a prosthetic leg, a power assist robot (actuator), etc. mechanically intervene directly in the lower limb movement. As another method for assisting and improving walking, a method has also been proposed in which the rhythm of walking is measured and a rhythm stimulus synchronized with walking is given to the walker to indirectly assist the lower limb movement (see, for example, Patent Documents 1 to 3).

[0003] However, in the method of directly intervening in the lower limb movement, since the walking motion is promoted by mechanically acting on the leg from the outside, there are problems in safety such as inducing a fall when a trouble occurs. In addition, since the leg of a walker with a walking disorder or problem is forcibly moved, it may cause pain to the walker. Furthermore, when the walker gets used to the state assisted by the walking improvement device, the motor ability of the leg may degenerate, and there is a risk that the walker may not be able to walk without the walking improvement device, and there are also problems from the viewpoint of the learning effect.

[0004] In order to address this problem, a device and method for indirectly assisting walking by intervening in the arm swinging motion have been proposed (Patent Document 4).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Document

[0006]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0007] The technique described in Patent Document 4 was premised on the wearer performing lower limb movement (walking movement). This was based on the premise that, through the coordination (simultaneous firing) of the respective central pattern generators (CPGs: Central Pattern Generator) that control the rhythmic movements of the upper and lower limbs, more specifically, limb coordination, walking improvement could be achieved through arm swing rhythm assistance.

[0008] Also, when using walking assistance devices such as canes or walkers, arm swing assistance during walking could not be used for training.

[0009] Furthermore, although arm swing assistance during walking could reduce the risk of falling compared to the case of wearing a robot on the legs, it was difficult to completely eliminate it.

[0010] This disclosure was made in such a situation, and one of the exemplary purposes of a certain aspect thereof is to provide a walking improvement device with a reduced risk of falling.

Means for Solving the Problems

[0011] As described above, conventional walking training was premised on the simultaneous firing of the upper limb rhythm CPG and the lower limb rhythm CPG. The inventors have conducted repeated studies without being bound by such a premise and have obtained new findings. That is, they have found that learning an appropriate arm swing rhythm pattern in the upper limb rhythm CPG without accompanying lower limb movement indirectly affects the lower limb rhythm CPG via the upper central nervous system and the spinal cord, and as a result, the lower limb movement walking pattern can be learned. The technology according to the present disclosure is based on such new findings.

[0012] A walking improvement method according to an aspect of the present disclosure includes a step of generating a periodic first rhythm by a walking improvement device, a step of synchronizing the first rhythm with a second rhythm that is the arm swing rhythm of a subject while the subject performs an arm swing movement in a seated position, and a step of the walking improvement device applying a rhythm stimulus corresponding to the first rhythm to the subject so that the second rhythm synchronizes with the first rhythm.

[0013] Another aspect of the present disclosure is a walking improvement device. The walking improvement device is wearable on a seated subject who is the target of walking improvement. The walking improvement device includes a rhythm generator capable of generating a periodic first rhythm, a rhythm detector that detects a second rhythm that is the arm swing rhythm of the subject while the subject performs an arm swing movement in a seated position, a synchronizer that adjusts the rhythm generator so that the first rhythm synchronizes with the second rhythm, and a drive unit that applies a rhythm stimulus corresponding to the first rhythm to the subject so that the second rhythm synchronizes with the first rhythm.

[0014] According to these aspects, the walking improvement device performs training to assist the arm swing for the upper limb of a subject who is performing an arm swing movement in a seated position. As a result, the lower limb movement can be improved via the coordination of the upper and lower limbs during subsequent walking.

[0015] In one aspect, the rhythm stimulus may include an assistive force by motor torque.

[0016] In one aspect, the rhythm stimulus may include at least one of visual, auditory, and tactile stimuli.

[0017] In one aspect, the first rhythm may be generated separately for the left and right arms of the subject, and the second rhythm may be detected separately for the left and right arms of the subject.

[0018] In addition, any combination of the above components, or components and expressions that are mutually replaced between methods, apparatuses, systems, etc., are also effective as aspects of the present invention or the present disclosure. Furthermore, the description of this item (means for solving the problem) does not explain all the essential features of the present invention. Therefore, sub-combinations of these described features can also be the present invention.

Advantages of the Invention

[0019] According to an aspect of the present disclosure, it is possible to improve walking performance while reducing the risk of falling.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0021] Hereinafter, preferred embodiments will be described with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. Also, the embodiments are illustrative and not restrictive of the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0022] FIG. 1 is a block diagram of a walking improvement device 100 according to an embodiment. The walking improvement device 100 includes a rhythm generator 110, a rhythm detector 120, a rhythm synchronizer 130, and a drive unit 140.

[0023] The walking improvement device 100 is worn by a seated subject 2 who is the target of walking improvement.

[0024] The rhythm generator 110 is an oscillator that generates a periodic first rhythm RY1. The first rhythm RY1 generated by the rhythm generator 110 can have its period and phase adjusted.

[0025] The rhythm detector 120 detects a second rhythm RY2, which is the subject 2's arm-swing rhythm, when the subject 2 who is the target of walking improvement performs an arm-swing motion while seated. The rhythm detector 120 can include an encoder, a gyro sensor, or a combination thereof.

[0026] Using the second rhythm RY2 detected by the rhythm detector 120, the rhythm synchronizer 130 adjusts the first rhythm RY1 generated by the rhythm generator 110 to synchronize with the second rhythm RY2.

[0027] The drive unit 140 generates an assist force F1 by motor torque when the subject 2 swings the arm forward or backward in synchronization with the first rhythm RY1 generated by the rhythm generator 110. The drive unit 140 alternately generates the assist force F1 for each of the left arm and the right arm, thereby synchronizing the second rhythm RY2 with the first rhythm RY1. That is, the mutual synchronization of the first rhythm RY1 and the second rhythm RY2 is realized by the rhythm synchronizer 130 and the drive unit 140. The mutual synchronization of the first rhythm RY1 and the second rhythm RY2 can be performed for each of the left arm and the right arm of the subject.

[0028] FIG. 2 is a diagram showing the walking improvement device 100. The walking improvement device 100 includes a harness 202, a left motor unit 210L, a right motor unit 210R, and a main body unit 220. The harness 202 fixes the walking improvement device 100 to a human. The left motor unit 210L and the right motor unit 210R correspond to the drive unit 140 in FIG. 1. The main body unit 220 incorporates a controller 222, a battery 224, and the like. The controller 222 implements functions such as the rhythm generator 110, the rhythm detector 120, and the rhythm synchronizer 130 in FIG. 1.

[0029] The left motor unit 210L and the right motor unit 210R are similarly configured and are collectively referred to as the motor unit 210. The motor unit 210 includes a motor (actuator). In conjunction with the motor of the motor unit 210, the movable part 212 rotates in the front-rear direction. The upper arm of a human is fixed to the movable part 212 via a fixing part 214. Therefore, the rotational movement of the motor is transmitted to the upper arm, and the arm swinging movement is assisted. The motor unit 210 incorporates a sensor and senses the arm swinging movement of the upper arm. The movement of the upper arm corresponds to the second rhythm RY2 in FIG. 1. The output of the sensor is transmitted to the controller 222 of the main body unit 220.

[0030] The above is the configuration of the walking improvement device 100.

[0031] The rhythm generator 110 and the rhythm synchronizer 130 are based on the model described in Non-Patent Document 1. The model will be described below.

[0032] · Coordination model of the four limbs The walking motion is regarded as the periodic motion of four oscillators corresponding to the four limbs, and a mathematical model expressing their interaction is applied to human bipedal walking motion to obtain a walking pattern generation model in rhythm walking assistance.

Equation

[0033] θ 1 , θ 2 , θ 3 , θ 4 represents the phase of the rhythm such that one period is 2π and the start of the motion is 0 (left arm, right foot), and π (left arm, right foot) in the periodic motion of the right arm, left arm, right foot, and left foot. Also, ω 1 , ω 2 , ω 3 , ω 4 represents the natural frequencies of the human right arm, left arm, right foot, and left foot, respectively. k 12 , k 14 , k 21 , k 23 , k 32 , k 41 is the coupling coefficient in the interaction between each oscillator. The coupling coefficient can be set to, for example, all 0.3 in the case of a healthy young population without bias in coupling. The walking pattern generation model can be regarded as corresponding to the second rhythm RY2 described above.

[0034] · Rhythm generation model of the robot The rhythm generation model on the robot side for realizing rhythm synchronization with humans is composed of a two-phase dynamic model as a mutual attraction model. That is, the rhythm generation model on the robot side includes a first module and a second module.

[0035] The first module realizes mutual synchronization between the human walking rhythm and the generated rhythm on the robot side. That is, it can be regarded as the above-mentioned rhythm synchronizer 130. Here, it is configured as a mutual pulling-in model using phase oscillators and is represented by equations (5) and (6).

Number

[0036] θ m_r , θ m_l respectively represent the phases of the generated rhythms on the robot side corresponding to the right motor and the left motor. Also, ω m_r , ω m_l represents the frequency of the rhythm. k m , k ml is the coupling strength. Also, θ 1 , θ 2 are respectively the phases in the periodic motion of the swinging of the right arm and the left arm on the human side, which are the inputs in this model.

[0037] The second module is a layer that controls the generated phase relationship. For example, it controls the natural frequency of module 1 so that the phase difference between the human walking model and the generated rhythm on the robot side approaches a preset target phase difference. The model of the second module is represented by equations (7) and (8).

Number

[0038] Here, Δθ d is the target phase difference, and μ represents the gain. For example, k m = 0.5, k m_rl = 0.5, μ = 0.16 can be determined in this way. Also, the target phase difference Δθ d can be set to 0.

[0039] · Human walking pattern generation model by rhythm assistance By considering the action term based on the upper limb motor drive timing of the robot observed from a human for the limb coordination model represented by formulas (1) to (4), a human walking pattern generation model by upper limb rhythm assist by the walking improvement device 100 can be constructed.

Number

[0040] Here, the fourth terms in formulas (9) and (10) are terms representing the interaction between the human arm swing rhythm and the generated rhythm on the robot side, and k m is the coupling strength. Also, α is a quantity reflecting the motor drive timing, and the sign is set so that the θ m_r and θ m_l observed from a human are delayed as the drive timing becomes later. In actual assistance, the larger α is, the later the motor drive timing becomes, and the motor is driven pulsatively with respect to the human arm swing motion. ρ is the gain of the action term of the motor drive timing, and for example, it is set to ρ = 0.03.

[0041] Figure 3 is a flowchart of the assist of the arm swing motion and the synchronization of the rhythm by the walking improvement device 100. In the figure, n represents the previous control cycle, and n + 1 represents the current control cycle. n is incremented for each control cycle. Also, Δt represents the control cycle.

[0042] Based on the above mutual attraction model, the phases θ m_l , θ m_r on the robot side are updated (S200).

Number

[0043] Subsequently, the drive determination of the motor is performed for the left side (S202). Specifically, it is determined whether the phase θ m_l is included in a predetermined range. If it is included in the predetermined range (Yes in S202), the motor generates torque and performs arm swing assist (S204). When the phase θm_l When it is outside the predetermined range (No in S202), the motor does not generate torque.

[0044] Similarly, for the right side, drive determination of the motor is performed (S206). Specifically, it is determined whether the phase θ m_r is included in the predetermined range. If it is included in the predetermined range (Yes in S206), the motor generates torque and performs arm swing assist (S208). When the phase θ m_r is outside the predetermined range (No in S206), the motor does not generate torque.

[0045] Subsequently, it is determined whether to start swinging the arm for the left side (S210). Specifically, it is determined whether the upper arm exceeds the trunk when viewed from the side of the body. More specifically, when the arm, that is, the movable part 212, is straight down along the trunk, the angle is set to 0°, and the time when the positive / negative of the angle changes can be defined as the start of arm swing. When assisting backward, the start of swinging back can be defined when the arm swings behind the trunk. When it is the start of arm swing (Yes in S210), the phase difference Δθ l between the person and the robot, and the phase advance speed ω m_l of the robot are updated (S212). When it is not the start of arm swing (No in S210), the phase difference Δθ l between the person and the robot, and the phase advance speed ω m_l of the robot are maintained.

[0046] For the right side as well, it is determined whether to start swinging the arm (S214). When it is the start of arm swing (Yes in S214), the phase difference Δθ r between the person and the robot, and the phase advance speed ω m_r of the robot are updated (S216). When it is not the start of arm swing (No in S214), the phase difference Δθ r between the person and the robot, and the phase advance speed ω m_r of the robot are maintained. Note that the order of the processes shown in FIG. 3 can be interchanged.

[0047] The above is the configuration of the walking improvement device 100.

[0048] Subsequently, the experimental results using the walking improvement device 100 will be described.

[0049] The experiment was conducted on seven subjects (A to G). Figure 4 is a flowchart of the experiment. Before performing the training for walking improvement by the walking improvement device 100, each subject performed bipedal walking, and the walking posture was measured by a walking posture analysis device (S100). The walking posture measured by the walking posture analysis device can be evaluated based on the trajectory of the ankle and the trajectory of the waist. The measurement of the ankle trajectory is based on the technique described in Non-Patent Document 2, and the measurement of the waist trajectory is based on the technique described in Non-Patent Document 3. This walking posture analysis device has sensors attached to the subject and can measure the trajectories of the sensors. For example, the sensors are attached to the subject's waist and ankles. The following items can be evaluated by the walking posture analysis device. · Stride length · Stride time, swing phase, stance phase · Walking speed The walking speed can be obtained as the value obtained by dividing the stride length by the stride time. · Waist trajectory The waist trajectory can be obtained as a two-dimensional waist trajectory seen from the back of a person. Thereby, the left and right lifting heights of the waist during walking, the magnitude of the lateral sway, and the asymmetry between the left and right lifting heights and the magnitude of the lateral sway can be calculated.

[0050] Subsequently, the subject wore the walking improvement device 100 according to the embodiment (S102). Then, the subject performed arm swinging exercises for 1 minute at a 5-minute interval 4 times while sitting (S104). The arm swinging exercise while sitting is the training for walking.

[0051] Subsequently, the walking improvement device 100 was removed from the subject (S106). Then, the subject performed bipedal walking again, and the walking posture was measured by the same walking posture analysis device as before (S108).

[0052] Then, the walking postures measured before training (S102) and after training (S108) were compared, and the effect of improvement in walking due to training was evaluated (S110).)

[0053] FIG. 5 is a diagram showing the waist trajectory of a certain subject before and after training. The horizontal axis represents the left-right direction, and the vertical axis represents the up-down direction. Before training, left-right asymmetry can be seen in the waist trajectory, while after training, it can be seen that the left-right asymmetry has improved.

[0054] FIG. 6 is a diagram showing the walking speed before and after training. Except for one subject G, an improvement in walking speed can be seen.

[0055] FIG. 7 is a diagram showing the stride length before and after training. Except for one subject G, it can be seen that the stride length has increased. It can be said that the walking speed is proportional to the product of the stride length and the cadence. The cadence coincides with the frequency of the arm-swinging motion, and assuming that the frequency of the arm-swinging motion is substantially the same before and after training, it can be said that the improvement in the stride length has brought about an improvement in the walking speed.

[0056] Thus, according to the walking improvement device 100 according to the present embodiment, walking can be improved by the arm-swinging motion in the seated position. Since it is in the seated position during training, there is no risk of falling, and it can be said that it is more stable than before.

[0057] Also, this walking improvement device 100 can be used by subjects who are using walking assistance devices such as canes and walkers.

[0058] Note that it is incorrect to regard the walking improvement method according to the present embodiment as an extension of the prior art. Conventional walking training was premised on the simultaneous firing of the upper limb rhythm CPG and the lower limb rhythm CPG. Based on such a premise, it is considered that the walking improvement method according to the present embodiment would not produce a great effect. However, in reality, as shown by the experimental results, a great improvement effect is produced. This can be considered to be due to the mechanism described below.

[0059] That is, the rhythm assist of arm swinging by the walking improvement device 100 promotes the learning of an appropriate arm swinging rhythm pattern in the upper limb rhythm CPG. Then, it indirectly affects the lower limb rhythm CPG via the higher center and the spinal cord, and the lower limb movement walking pattern is learned. As a result, it is considered that walking is improved. Thus, it can be said that the walking improvement method according to the present embodiment is based on a mechanism fundamentally different from conventional walking improvement.

[0060] The embodiments have been described above. It is understood by those skilled in the art that these embodiments are illustrative, and various modifications are possible for the combination of each of these constituent elements and each processing process, and such modifications are also within the scope of the present invention. Hereinafter, such modifications will be described.

[0061] (Modification Example 1) The arm swing assist can assist at the time of the forward swing or the backward swing of the arm, or at both timings. At this time, the assist timing and the assist force may be changed at the time of each assist.

[0062] (Modification Example 2) In addition to the arm swing assist, the rotation of the shoulder may be performed in order to promote the rotation of the trunk. And it is advisable to specify an appropriate rotation angle. Also, a rotating chair may be used as the chair.

[0063] (Modification Example 3) In order to enhance the effect, in addition to the arm swinging movement in the sitting position, the subject may perform foot tapping. At this time, a weight may be attached so as to impose a load on the legs. And it is advisable to specify an appropriate foot lifting height.

[0064] (Modification Example 4) When improving walking for subjects with a left - right difference in walking, such as paralytic patients, the assisting force, timing, and rhythm synchronization method may be changed between the left and right. Also, when severe motor impairment is observed in the arm on the affected side, only the rhythm of the arm swing on the healthy side may be detected, and based on that information, assistance may be provided to both arms.

[0065] (Modification Example 5) Regarding the rhythm detection of a person in the embodiment, although it was described for the case of detecting the movement of the upper arm, any one of the movements of the forearm, hand, shoulder, trunk, lower limb, or any arbitrary combination thereof may be used to detect the situation of the person's arm swing from them.

[0066] (Modification Example 6) In the embodiment, regarding the control of a person's arm swing, it was described for the case of assisting the upper arm, but a rhythm may be presented to another part of the upper limb, specifically, any one of the forearm, hand, shoulder, elbow, or any arbitrary combination. Not only the upper arm, but also other parts of the upper limb can affect the arm swing rhythm.

[0067] (Modification Example 7) Instead of, or in addition to, the mechanical intervention on the arm movement by the fixing part 214, auditory, visual, and tactile rhythm stimuli synchronized with the arm swing movement may be given. These external stimuli can affect walking and arm swing rhythm (Non - Patent Documents 4, 5). Thereby, the walking movement of the subject 2 can be improved more effectively. When giving auditory, visual, and tactile rhythm stimuli, the parameters of the fourth term in formulas (9) and (10) will be modified.

[0068] (Modification Example 8) In the embodiment, the case of measuring the arm swing movement using an encoder or a gyro sensor was described, but in addition to this, an acceleration sensor or a speed sensor may be used. Alternatively, arm swing movement information data obtained from an optical motion capture or a camera may be utilized.

[0069] (Modification Example 9) In the embodiment, the case of improving the walking motion of the elderly, disabled, and injured or sick people has been described, but the application is not limited thereto. It can also be applied to healthy people, athletes, fashion models, etc. who desire to improve their walking form.

[0070] The embodiment only shows the principle and application of the present invention. In the embodiment, many modifications and arrangement changes are allowed as long as they do not deviate from the idea of the present invention defined in the claims.

Explanation of Reference Numerals

[0071] 100 Walking improvement device 110 Rhythm generator 120 Rhythm detector 130 Rhythm synchronizer 140 Driving unit 202 Harness 210 Motor unit 220 Main body unit 222 Controller 224 Battery

Claims

1. A step of generating a periodic first rhythm by a walking improvement device; A step of synchronizing the first rhythm with a second rhythm that is the subject's arm-swinging rhythm while the subject to be improved in walking performs an arm-swinging motion in a seated position; A step of the walking improvement device applying a rhythm stimulus corresponding to the first rhythm to the subject so that the second rhythm synchronizes with the first rhythm; A walking improvement method characterized by comprising the above.

2. The walking improvement method according to claim 1, wherein the rhythm stimulus includes an assist force by motor torque.

3. The walking improvement method according to claim 1 or 2, wherein the rhythm stimulus includes at least one of visual, auditory, and tactile stimuli.

4. The first rhythm is separately generated for the subject's left arm and right arm, The second rhythm is separately detected for the subject's left arm and right arm, Mutually synchronizing the first rhythm and the second rhythm of the left arm, The walking improvement method according to claim 1 or 2, characterized by mutually synchronizing the first rhythm and the second rhythm of the right arm.

5. The walking improvement method according to claim 2, characterized in that the assist forces, assist timings, assist times, and assist directions on the left and right can be adjusted to different values.

6. It is wearable on a seated subject to be improved in walking, A rhythm generator capable of generating a periodic first rhythm, A rhythm detector that detects a second rhythm that is the subject's arm-swinging rhythm while the subject performs an arm-swinging motion in a seated position, A synchronizer that adjusts the rhythm generator so that the first rhythm synchronizes with the second rhythm, A drive unit that applies a rhythm stimulus corresponding to the first rhythm to the subject so that the second rhythm synchronizes with the first rhythm; A walking improvement device characterized by comprising the above.

7. The walking improvement device according to claim 6, wherein the drive unit includes a motor, and as the rhythm stimulus, a force by motor torque is applied to the subject's arm.

8. The walking improvement device according to claim 6 or 7, wherein the rhythm stimulus includes at least one of visual, auditory, and tactile stimuli.

9. The rhythm generator generates separate first rhythms for the subject's left arm and right arm, The rhythm detector detects separate second rhythms for the subject's left arm and right arm, The synchronizer and the drive unit mutually synchronize the first rhythm and the second rhythm of the left arm, and the first rhythm and the second rhythm of the right arm are mutually synchronized. The walking improvement device according to claim 6 or 7, characterized in that.

10. The detector includes a sensor attached to the shoulder, trunk, or lower limb of the subject, and detects the second rhythm based on the output of the sensor. The walking improvement device according to claim 6 or 7, characterized in that.

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