JP2020137543A - Walking state detector - Google Patents

Abstract

To detect knee bending motion while suppressing cost rise and logic complication.SOLUTION: The walking state detector is provided with a rotary part that rotates at the knee joint part, and is fitted at least to the knee joint part in the leg. The detector includes: a first detecting means 11 that detects knee joint torque which works on the knee joint part in the rotary part; a second detecting means 12 that detects a value corresponding to a leg posture; and an operation part 14 for detecting a walking state and a knee bending state that are contained in one walking cycle period, in accordance with the combination of a plurality of results including at least a result of comparison of the knee joint torque detected by the first detecting means 11 with a threshold value for the preliminarily set first detecting means 11, and a result of comparison of the value corresponding to the leg posture detected by the second detecting means 12 with a threshold value for the preliminarily set second detecting means 12.SELECTED DRAWING: Figure 1

Description

The present invention relates to a walking state detection device.

In recent years, when performing walking training, a walking training device is used to assist the walking of a patient. The gait training device can support the knee break when the weight is on the leg, and can activate the actuator so as not to interfere with the movement when the leg is swung up. The period during which the knee break is supported is defined as the auxiliary period, and the period during which the movement is not hindered is defined as the free period.

It is known that the switching period between the assist period and the free period of this assist is slightly different from the contact period of the sole of the foot. Therefore, there is known a method of setting a switching period by detecting a plurality of leg posture signals instead of a foot sensor and comparing the detection results with a preset threshold value.

As a technique in such a field, there is Japanese Patent Application Laid-Open No. 2013-1235332. In the walking state detecting device described in this publication, the walking state included in one walking cycle period can be detected by using the sensor attached to the leg.

Japanese Unexamined Patent Publication No. 2013-123532

However, in the above-mentioned conventional directional training device, the movement in the auxiliary period and the movement in the free period are assumed for the walking trainer, but the situation in which the knee is broken is not assumed. .. In addition, adding a sensor to detect a knee break in a walking trainer is expected to increase costs and complicate logic.
The present invention provides a walking state detecting device capable of detecting a knee bending motion while suppressing an increase in cost and complication of logic.

The walking state detecting device according to the present invention is a walking state detecting device having a rotating portion that rotates at the knee joint portion and is attached to at least the knee joint portion at the leg portion, and the rotating portion has the said. With respect to the first detecting means for detecting the knee joint torque applied to the knee joint, the second detecting means for detecting the value according to the posture of the leg, and the preset threshold value for the first detecting means. , The result of comparing the knee joint torque detected by the first detecting means and the posture of the leg detected by the second detecting means with respect to the preset threshold value for the second detecting means. It is provided with a calculation unit for detecting a walking state and a knee-breaking state included in one walking cycle period according to a combination of a result of comparing the corresponding values and a plurality of results including at least.
Thereby, the walking state including the knee bent state can be detected by the combination of the detection results of the first detecting means and the second detecting means.

As a result, it is possible to detect knee bending motion while suppressing cost increase and logic complexity.

It is a figure which shows the structure of the walking state detection device. It is a figure which showed the walking state of a pedestrian. It is a figure which showed the relationship between the value acquired by the 1st and 2nd sensors, and the assist state. It is a figure which shows the angle of the lower leg. It is a figure which shows the flow which determines a walking state.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the walking state detecting device 1 has a first sensor (first detecting means) 11 for detecting the torque of the knee joint (hereinafter, knee joint torque) and a second sensor for detecting the posture of the leg. Sensor (second detection means) 12, a wearable device 13 for mounting the first sensor 11 and the second sensor on the leg of a walking trainee, and the sensors of the first sensor 11 and the second sensor 12. A calculation unit 14 that performs calculation processing of data and determines switching of an assist state is provided. It should be noted that the wearable device 13 has a rotating portion that rotates at the knee joint portion of the walking trainee, and will be described as being attached to at least the knee joint portion at the leg portion.

Here, as shown in FIG. 2, the walking state of the walking trainee will be described as changing to Initial Contact, Lodaing Response, Mid Stance, Terminal Stance, Pre Swing, and Initial swing. Based on healthy legs, the state from Lodaing Response to Terminal Stance is a free period that does not hinder the swinging of the legs, and Pre Swing and Initial Swing are an auxiliary period that supports knee breakage. In the knee-breaking period, the transition from the auxiliary period to the knee-breaking state shall be made. When viewed based on the affected leg equipped with the wearable device 13, the free period is the pre-swing and the initial swing, and the auxiliary period is from Lodaing Resonse to the terminal stance.

FIG. 3 is an example showing what the values acquired by the first sensor 11 and the second sensor are according to the walking state of the walking trainee. In FIG. 3, as an example, a threshold value for the first sensor, a threshold value for the second sensor, and a threshold value set for eliminating erroneous determination are set in advance in the calculation unit 14. It shows the state.

The first sensor 11 is, for example, a torque sensor provided in the rotating portion and detecting the knee joint torque T applied to the knee joint. The first sensor 11 outputs the detected knee joint torque value to the calculation unit 14.

The second sensor 12 is a sensor that detects the posture of the leg. For example, as shown in FIG. 4, the second sensor 12 detects the angle θ at which the lower leg is tilted with reference to the perpendicular line drawn from the position of the knee joint of the walking trainer toward the ground. In the walking state detection device 1, this angle θ is treated as indicating the posture of the leg. The second sensor 12 outputs the value of the angle θ representing the detected posture of the lower leg to the calculation unit 14.

The wearable device 13 mounts and fixes the first sensor 11 and the second sensor 12 on the legs of the walking trainee. For example, a rotating portion mounted on the wearable device 13 is arranged near the knee joint portion, and the operating state of the rotating portion changes according to the calculation result of the calculation unit 14, so that the walking trainee You can change the assist state for.

The calculation unit 14 performs calculation processing of the values input from the first sensor 11 and the second sensor 12, and determines the switching of the assist state of the rotating unit of the wearable device 13. The calculation unit 14 performs a comparison determination with respect to the threshold value for the first sensor for performing a comparison determination with respect to the value acquired by the first sensor 11 and the value acquired with the second sensor 12 in advance. The threshold value for the second sensor for the purpose is stored.

Here, the threshold value for the first sensor stored in the calculation unit 14 is the torque threshold value T_Thr for detecting the knee bending state. Specifically, the torque of the knee joint is monitored in advance when the pedestrian performs gait, and a value equal to or greater than the maximum value is set as the torque threshold value T_Thr for detecting the knee bending state.

Further, the thresholds for the second sensor stored in the calculation unit 14 are the threshold SW2ST_thr that becomes the auxiliary period, the threshold SWflag_thr immediately before the auxiliary period, the threshold ST2SW_thr that becomes the free period, and immediately before the free period. The threshold of SWflag_thr. Specifically, the pedestrian executes the gait in advance, and sets the threshold values for these second sensors according to the timing of the free period and the auxiliary period from the gait state. Further, the calculation unit 14 sets the erroneous determination removal flag threshold value for removing the erroneous determination due to chattering from the threshold value for the second sensor.

As shown in FIG. 3, the erroneous judgment removal flag threshold value is chattering when the threshold value for determining that the transition to the auxiliary period has shifted is set to a value close to the threshold value for determining the transition to the free period. It is set to suppress the occurrence of erroneous determination due to such factors. Further, the erroneous determination removal flag threshold value is not limited to this setting, and a plurality of erroneous determination removal flag threshold values may be set in order to eliminate other erroneous determinations.

Further, the calculation unit 14 stores the walking state st of the walking trainee. In other words, the calculation unit 14 determines to change the assist state according to the walking state st of the walking trainee, but determines the assist state determined immediately before in order to change the current assist state. It is assumed that the walking state st at that time is memorized. For example, the walking state st is set to 1 in the early stage of the free period, the walking state st is set to 2 in the latter half of the free period, the walking state st is set to 3 in the early stage of the auxiliary period, and the walking state st is set to 4 in the latter stage of the auxiliary period. .. As will be described later, when the current walking state st is 3 or 4, it may be determined that the knee is broken.

Next, with reference to FIG. 5, a method of determining whether the walking state detecting device 1 is in the free period, the auxiliary period, or the knee bending state and switching the assist state will be described.

The state of the walking trainee is acquired by the first sensor 11 and the second sensor 12 (S1). That is, the knee joint torque T, which is the torque applied to the knee joint, is acquired by the first sensor 11. Further, the second sensor 12 acquires the angle θ at which the lower leg is tilted. Information on the knee joint torque T and the angle θ is input to the calculation unit 14, respectively.

The calculation unit 14 performs signal processing (S2). For example, abnormal values may be recorded in the knee joint torque T and the angle θ due to noise or the like, and when these acquired values are continuously arranged along the time, they appear as high frequency components. Therefore, the calculation unit 14 performs signal processing for removing high frequency components.

The calculation unit 14 confirms the walking state st determined immediately before (S3). If the walking state st is 1, the process proceeds to S11, if the walking state st is 2, the process proceeds to S21, if the walking state st is 3, the process proceeds to S31, and if the walking state st is 4, the process proceeds to S41.

When the immediately preceding walking state st is 1, it is determined whether or not the angle θ crosses the threshold value STflag_thr immediately before the auxiliary period (S11). If the angle θ does not straddle the threshold STflag_thr (No in S11), the current walking state st remains 1 (S12), and it is determined that the free period is in progress (S13). If the angle θ straddles the threshold value STflag_thr (Yes in S11), the current walking state st is changed to 2 (S14), and it is determined that the free period is in effect (S15).

When the walking state st immediately before is 2, it is determined whether or not the angle θ crosses the threshold value ST2SW_thr in the free period (S21). If the angle θ does not straddle the threshold value ST2SW_thr (No in S21), the current walking state st remains at 2 (S22), and it is determined that the free period is in effect (S23). If the angle θ straddles the threshold value ST2SW_thr (Yes in S21), the current walking state st is changed to 3 (S24), and whether or not the knee joint torque T exceeds the torque threshold value T_Thr for detecting the knee bending state. Is determined (S25). If the knee joint torque T does not exceed the torque threshold value T_Thr (No in S25), it is determined that the knee joint torque T is the auxiliary period (S26). If the knee joint torque T exceeds the torque threshold value T_Thr (Yes in S25), it is determined that the knee is in a broken state (S27).

When the processing of S21 is started, the walking state st determined immediately before is 2 and is in the free period, but after the walking state st is changed to 3 indicating the auxiliary period in S24, in S27. It is judged that the knee is broken. Therefore, in the state determined to be the auxiliary period, it can be treated as the state determined to be the knee broken state.

When the walking state st immediately before is 3, it is determined whether or not the angle θ crosses the threshold value STflag_thr immediately before the free period (S31). If the angle θ does not straddle the threshold value STflag_thr (No in S31), the current walking state st remains at 3 (S32), and whether or not the knee joint torque T exceeds the torque threshold value T_Thr for detecting the knee bending state. (S33). If the knee joint torque T does not exceed the torque threshold value T_Thr (No in S33), it is determined that the knee joint torque T is in the auxiliary period (S34). If the knee joint torque T exceeds the torque threshold value T_Thr (Yes in S33), it is determined that the knee is in a broken state (S35).

If the angle θ straddles the threshold value STflag_thr (Yes in S31), the current walking state st is changed to 4 (S36), and whether or not the knee joint torque T exceeds the torque threshold value T_Thr for detecting the knee bending state. Is determined (S37). If the knee joint torque T does not exceed the torque threshold value T_Thr (No in S37), it is determined that the knee joint torque T is in the auxiliary period (S38). If the knee joint torque T exceeds the torque threshold value T_Thr (Yes in S37), it is determined that the knee is in a broken state (S39).

When the immediately preceding walking state st is 4, it is determined whether or not the angle θ crosses the threshold value SW2ST_thr which is the auxiliary period (S41). If the angle θ does not straddle the threshold value SW2ST_thr (No in S41), the current walking state st remains at 4 (S42), and whether or not the knee joint torque T exceeds the torque threshold value T_Thr for detecting the knee bending state. (S43). If the knee joint torque T does not exceed the torque threshold value T_Thr (No in S43), it is determined that the knee joint torque T is in the auxiliary period (S44). If the knee joint torque T exceeds the torque threshold value T_Thr (Yes in S43), it is determined that the knee is in a broken state (S45).

If the angle θ straddles the threshold value SW2ST_thr (Yes in S41), the current walking state st is changed to 1 (S46), and it is determined that the free period is in effect (S47).

In this way, it is possible to determine whether or not the knee is broken during the auxiliary period while changing the value of the walking state st when the threshold value is crossed. Further, whether or not the knee joint torque T detected by the first sensor 11 exceeds the threshold value for detecting the knee bending state, and whether or not the value detected by the second detecting means 12 exceeds a predetermined threshold value. Based on the knee, the walking state can be determined and the assist state can be changed.

Since the sensor for determining the free period and the auxiliary period can be used to determine the knee bending state without adding a sensor, the cost can be reduced. In addition, the logic for changing the assist state is intuitively easy to understand because it is a two-step judgment process in which the switching between the free period and the auxiliary period is determined by the angle θ and the knee joint torque T is used to determine the knee break state. It can be said that.

From the above, the walking state detecting device 1 can detect not only one walking cycle period but also a knee bending state with a simple configuration.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit.

For example, instead of detecting the knee joint torque T, the wearable device 13 may be equipped with a damper mechanism, and the pressure inside the damper may be determined to determine the knee bending state.

Further, as the detection of the knee joint torque T, instead of using the first sensor 11, the frame distortion of the wearable device 13 may be detected.

Further, in order to detect the knee joint torque T, the wearable device 13 may be equipped with a load cell as the first sensor 11.

Further, the detection of the leg posture by the second sensor 12 is not limited to the detection of the state of the lower leg, but may be performed by detecting the state of the thigh.

1 Walking state detection device 11 First sensor (first detection means)
12 Second sensor (second detection means)
13 Wearable device 14 Calculation unit

Claims (1)

A walking state detecting device having a rotating portion that rotates at the knee joint portion and being attached to at least the knee joint portion at the leg portion.
A first detecting means for detecting the knee joint torque applied to the knee joint portion in the rotating portion, and
A second detecting means for detecting a value according to the posture of the leg, and
The result of comparing the knee joint torque detected by the first detection means with respect to the preset threshold value for the first detection means and the preset threshold value for the second detection means. The walking state and the knee-bending state included in one walking cycle period are detected according to the combination of the result of comparing the values according to the posture of the leg detected by the second detection means and a plurality of results including at least. It has a calculation unit and
Walking state detection device.

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