JP2003135543A - Walk assisting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a walk assisting device enabling a walker to walk in a natural posture while preventing the walker's myodynamia deterioration or the like. SOLUTION: In this walk assisting device, actuators 11, 12 are controlled by a control unit 2 to apply compensation force for steadily compensating load brought wit the use of the device, to a leg body. As for the leg body determined to be in the state of being off the floor by a leg body state determining means 21, the actuators 11, 12 are controlled to apply auxiliary force to the leg body only when a first angle (the tilt angle of the thigh part to a vertical direction) θ1 measured by a first angle measuring means 221 is in a range of 0 deg.-+10 deg. and the walking speed v measured by a walking speed means 224 is 2.0 [km/h] or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for assisting the walking of a pedestrian by applying an assisting force to the leg of the pedestrian via an actuator.

[0002]

2. Description of the Related Art By using such a walking assist device,
Even a person with weakened muscles such as legs can walk without feeling pain when going up and down stairs or slopes.

[0003]

However, if a person keeps walking while relying only on the assisting force, the muscle force of the leg decreases almost without being used. Therefore, the assisting force applied to the leg in order to avoid such a situation. Is preferably moderately suppressed. In addition, depending on the timing at which the assisting force is applied, the pedestrian may be forced to walk in an unnatural unintended posture, which may cause discomfort.

[0004] Therefore, it is an object of the present invention to provide a walking assist device which enables a pedestrian to walk in a natural posture while preventing the pedestrian from weakening his muscles.

[0005]

Means for Solving the Problems A walking assist device of the present invention for solving the above problems is a leg condition determining means for determining whether a leg of a pedestrian is in a landing state or a leaving state. And a first angle measuring means for measuring the inclination angle of the pedestrian's thigh with respect to the vertical direction as the first angle, a walking speed measuring means for measuring the walking speed of the pedestrian, and a load accompanying the use of the device. The actuator is controlled so that the compensating force is applied to the leg body, and the first angle measured by the first angle measurement means is determined for the leg body determined by the leg state determination means to be in the bed leaving state. 0 ° to + 10 °
And a control means for controlling the actuator so that the assisting force is applied to the leg only when the walking speed measured by the walking speed means is 2.0 [km / h] or more. It is characterized by having.

According to the knowledge obtained by the inventor of the present application, the leg is in the bed leaving state, and the first angle of the leg is 0 ° to +1.
When the angle is 0 °, the thigh of the leg is swung forward due to the inertial force, and the muscular force of the pedestrian is scarcely used for the swing. The “first angle” is the angle of inclination of the thigh with respect to the vertical direction, and is defined as positive in the front and negative in the rear with respect to the basic frontal plane, as described later. Further, in this case, even if the assisting force is applied to the leg, the posture of the leg is maintained equivalent to that in the case where the assisting force is not applied.

Therefore, according to the present invention, since the assisting force is applied to the leg while the muscle force is hardly used, it is possible to avoid the situation where the applying of the assisting force causes the decrease of the muscle force. Further, even if the assisting force is applied to the leg, the posture of the leg is the same as in the case where the assisting force is not applied. Therefore, it is possible to avoid a situation in which the pedestrian is forced to walk in an unnatural posture.

The present invention further comprises a hip joint angular velocity measuring means for measuring the hip joint angular velocity of the leg of the pedestrian, and the leg condition determining means is the first angle measuring means for the one leg. When the angle is positive and the hip joint angular velocity measured by the hip joint angular velocity measuring means is a positive predetermined angular velocity or more, and the first angle measured by the first angle measuring means for the other leg is negative and the hip joint angular velocity measuring means When the measured hip joint angular velocity is equal to or less than a negative negative angular velocity, it is determined that the one leg is in a bed leaving state and the other leg is in a landing state.

According to the present invention, it is possible to determine whether the legs are in the landing state or the bed leaving state based on the qualitative consideration regarding the movement of the left and right legs during walking as described later.

Further, according to the present invention, the second angle measuring means for measuring the inclination angle of the shin of the pedestrian with respect to the vertical direction as the second angle, and the lengths of the thigh and the shin of the pedestrian are stored in memory. A first storage means, wherein the walking speed measurement means has lengths of the thigh and shin which are stored and held in the first storage means, a first angle measured by the first angle measurement means, and a second angle. The walking speed of the pedestrian is measured based on the second angle measured by the angle measuring means.

According to the present invention, the walking speed of the pedestrian can be measured based on the elementary geometrical consideration regarding the length of the leg of the pedestrian and the bending condition of the joint as described later.

According to the present invention, the walking speed of the pedestrian is measured by the second storage means for storing and holding the correlation between the walking speed of the pedestrian and the assisting force applied to the leg of the pedestrian. The assisting force determining means for determining the assisting force applied to the leg via the actuator based on the walking speed and the correlation stored and held by the second storage means. And

According to the present invention, it is possible to apply an appropriate assisting force to a leg of a pedestrian based on a correspondence relationship that is built in advance as described below.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a walking assist device of the present invention will be described with reference to the drawings. FIG. 1 is a configuration explanatory view of a walking assist device of the present embodiment, FIG. 2 is a flow chart showing a control method of the walking assist device of the present embodiment, and FIG. 3 is a flowchart of walking speed in the walking assist device of the present embodiment. FIG. 4 is an explanatory diagram of a measurement method, and FIG. 4 is a flowchart showing a leg state determination method in the walking assistance device of the present embodiment,
FIG. 5 is an explanatory diagram of a method of determining an assisting force by the walking assist device of this embodiment, FIG. 6 is an explanatory diagram of an assisting force by the walking assist device of this embodiment, and FIG. 7 is a walking assist of this embodiment. It is a 1st angle (theta) ₁ -2nd angle (theta) ₂ plane orbit diagram in an apparatus.

The walking assist device shown in FIG. 1 includes left and right hip joint actuators 11 attached to the abdomen of a pedestrian to give an assisting force around the hip joint, and an assisting force around the knee joint attached to the knee of the pedestrian. The left and right knee joint actuators 12 that provide the actuators, a control unit (control means) 2 that controls the operation of the actuators 11 and 12, and a battery 3 such as a Ni-MH battery that supplies electric power to the actuators 11 and 12. ing. The control unit 2 and the battery 3 are stored in a backpack 4 mounted on the back of a pedestrian.

The hip joint actuator 11 applies an assisting force around the hip joint via a trunk supporter 51 and a thigh supporter 52 attached to the waist and thighs of a pedestrian. The knee joint actuator 12 applies an assisting force around the knee joint via the thigh supporter 52 and the lower leg supporter 53 attached to the thighs and lower legs of the pedestrian.

The walking assist device is attached to the upper body of a pedestrian and comprises a gyro sensor 61 for measuring the angular velocity of the upper body in the vertical direction, and a longitudinal acceleration sensor 62 for measuring the longitudinal acceleration. ing. Further, the gyro sensor 63 is attached to the waist of the pedestrian and measures the angular velocity of the waist with respect to the vertical direction. The gyro sensor 63 is provided with the longitudinal acceleration sensor 64 and the vertical acceleration sensor 65 for measuring acceleration in the longitudinal and vertical directions. The hip joint angle at the waist of the pedestrian, that is, the angle of the thigh with respect to the waist φ ₁
Left and right hip joint angle sensor 66 for measuring the knee joint angle In the knee, i.e., and a right and left knee joint angle sensor 67 for measuring the angle phi ₂ of the leg portion with respect to the thigh.

The control unit 2 includes a leg condition determining means 21.
And a first angle measuring means 221 and a second angle measuring means 22.
2, hip joint angular velocity measuring means 223, walking speed measuring means 224, first storing means 231, and second storing means 23.
2 and auxiliary force determining means 24.

The leg condition determining means 21 is the first as described later.
Based on the first angle θ _{1 and the} like measured by the angle measuring unit 221, whether the left and right legs are in the landing state in which the soles of the feet are landed or the soles are in the bed leaving state To judge.

The first angle measuring means 221 determines the first angle based on the waist inclination angle φ with respect to the vertical direction measured based on the output from the waist gyro sensor 63 and the hip joint angle φ ₁ measured by the hip joint angle sensor 66. 1 angle (angle of the thigh with respect to the vertical direction) θ ₁ is measured. The second angle measuring unit 222 uses the first angle θ ₁ measured by the first angle measuring unit 221 and the knee joint angle φ ₂ measured by the knee joint angle sensor 67 to determine the second angle (shin to the vertical direction). Angle) θ ₂ is measured. The hip joint angular velocity measuring means 223 measures the hip joint angular velocity ω (= dφ ₁ / dt) by time-differentiating the hip joint angle φ ₁ measured by the hip joint angle sensor 66. Walking speed measuring means 2
24 measures the walking speed v of the pedestrian based on the first and second angles θ ₁ , θ _{2 and the} like measured by the first and second angle measuring means 221 and 222.

The first storage means 231 is composed of a ROM, a RAM and the like, and stores and holds the lengths l ₁ and l ₂ of the thigh and lower leg of the pedestrian measured in advance. Second storage means 232
Is preliminarily constructed by experimental results and stores and holds the correspondence relationship (see FIG. 6) between the walking speed v and the assisting force F applied to the legs.

The assisting force determining means 24 determines the assisting force applied around the hip joint and the knee joint via the actuators 11 and 12, based on the walking speed v measured by the walking speed measuring means 22 as described later. .

Then, the control unit 2 controls the current value of the drive motor (not shown) of the actuators 11 and 12 so that the assisting force determined by the assisting force determining means 24 is applied.

The function of the walking assist device having the above structure will be described with reference to FIGS.

First, the first angle measurement means 221, the second angle measurement means 222, the hip joint angular velocity measurement means 223, and the walking speed measurement means 224 are used to determine the first angle θ for the left and right legs.
₁ , the second angle θ ₂ , the hip joint angular velocity ω, and the walking velocity v are measured (FIG. 2s1).

Specifically, the first angle measuring means 222 uses the waist inclination angle φ with respect to the vertical direction measured by the waist gyro sensor 63 and the hip joint angle φ ₁ measured by the hip joint angle sensor 66. The first angle θ ₁ is measured according to the equation (1) (see FIG. 3). The inclination angle φ of the waist is defined as positive when the waist is inclined forward with respect to the basic frontal plane (a vertical plane that divides the body into front and back) and negative when the waist is inclined rearward. Also, the hip joint angle φ ₁
Includes a hip joint, and is defined as positive when the thigh is in front and negative when the thigh is in front of a plane obtained by inclining the basic frontal plane above the hip joint by an inclination angle φ like the waist. Further, the first angle θ ₁ includes a hip joint and is defined as positive in the front and negative in the rear with reference to a plane parallel to the basic frontal plane.

Θ ₁ = φ ₁ −φ (1)

Further, the second angle measuring means 222 uses the following equation using the first angle θ ₁ measured by the first angle measuring means 221 and the knee joint angle φ ₂ measured by the knee joint angle sensor 67. The second angle θ ₂ is measured according to (2) (see FIG. 3). The knee joint angle φ ₂ includes the hip joint,
With respect to a plane obtained by inclining the basic frontal plane below the hip joint by the first angle θ ₁ , the case where the shin is in front is defined as negative, and the case where it is behind is defined as positive. The second angle θ ₂ includes the knee joint and is defined as positive in the front and negative in the rear with reference to a plane parallel to the basic frontal plane.

Θ ₂ = θ ₁ −φ ₂ (2)

Further, the hip joint angular velocity measuring means 223 time-differentiates the hip joint angle φ ₁ measured by the hip joint angle sensor 66 to calculate the hip joint angular velocity ω (= dφ ₁ / d).
t) is measured. The hip joint angular velocity ω is defined as positive when the thigh moves in the walking direction and negative when the thigh moves in the opposite direction to the walking direction.

Further, the walking speed measuring means 224, after both legs of the pedestrian are in the landing state (dotted line in FIG. 3: time t _i ), one leg is left on the other leg and After the user leaves the bed, the walking speed v is measured again based on the moving distance and the required time until both legs are in the landing state (solid line in FIG. 3: time t _{i + 1} ). When the upward acceleration of the waist measured based on the output of the vertical acceleration sensor 65 of the waist exceeds a predetermined threshold, the time when both legs are in the landing state is set. Further, at the time, the first and second angle measuring means 2
21 and 222, the first and second angles θ ₁ and θ
₂ and the thigh and shin lengths l ₁ and l ₂ of the pedestrian stored and held by the first storage means 231 based on the following equation (3) based on the geometrical consideration of the walking speed v. Measure according to.

V = d / (t _{i + 1} −t _i ), d = l ₁ sin θ ₁ (t _{i + 1} ) + l ₂ sin θ ₂ (t _{i + 1} ) −l ₁ sin θ ₁ (t _i ) _{−1 2} sin θ ₂ (t _i ) (3)

Subsequently, the leg state determination means 21 determines whether the left and right legs are in the bed leaving state or the floor sitting state, respectively (FIG. 2s2). Specifically, as shown in FIG. 4, whether or not the first angle θ ₁ is 0 or more for the right leg, the hip joint angular velocity ω
Is greater than or equal to a positive predetermined angular velocity c ₊ (> 0), is the first angle θ _{1 of the} left leg negative, or is the hip joint angular velocity ω less than or equal to a negative predetermined angular velocity c _- (<0)? Judged (s21
a-24a). Then, when all of these four conditions are satisfied (YES in all of s21a to 24a), it is determined that the right leg is in the leaving state and the left leg is in the landing state (s25a).

When any of the conditions is not satisfied (NO in any of s21a to 24a), whether the first angle θ _{1 of the} left leg is 0 or more, the hip joint angular velocity ω is a predetermined positive angular velocity. It is determined whether or not c ₊ (> 0) or more, whether or not the first angle θ ₁ is negative for the right leg, and whether or not the hip joint angular velocity ω is less than or equal to a negative negative angular velocity c ₋ (<0) (s21b).
~ 24b). Then, when all of these four conditions are satisfied (YES in all of s21b to 24b), it is determined that the right leg is in the landing state and the left leg is in the bed leaving state (s
25b). When all of the above eight conditions are not satisfied (s21a to 24a and 21b to 24b are all NO), the first angle θ ₁ and the second angle θ ₂ are measured again (FIG. 4A, FIG. 2s1).

For the leg determined by the leg state determining means 21 to be in the bed-free state, the control unit 2 subsequently determines whether or not the first angle θ ₁ is 0 ° or more and 10 ° or less. (S3) Further, it is determined whether or not the walking speed v is equal to or higher than a predetermined speed v ₀ = 2.0 [km / h] (s).
4).

When it is determined that the first angle θ ₁ is 0 ° or more and 10 ° or less and the walking speed v is the predetermined speed v ₀ = 2.0 [km / h] or more (YES in s3 and s4), the assistance The force determining means 24 determines the assisting force (s5). Specifically, the assisting force determining unit 24 reads the correspondence relationship between the walking speed v and the assisting force stored and held by the second storage unit 232.
The assisting force is determined based on this and the walking speed v measured by the walking speed measuring means 224. Figure 5 shows walking speed v
The following shows the correspondence relationship between the auxiliary force and the assisting force. It can be seen that the assisting force is determined to be larger as the walking speed v increases.

Subsequently, the control unit 2 controls the hip joint actuator 11 and, if necessary, the knee joint actuator 1 appropriately.
By controlling the current value of the second drive motor (not shown),
The assisting force determined by the assisting force determining means 24 is applied to the legs (s6).

It should be noted that the control unit 2 causes friction, etc., via the hip joint and knee joint actuators 11 and 12,
A "compensation force" that constantly compensates for the load associated with the use of the device is applied to the legs of the pedestrian. Therefore, by imparting "compensation power" to the legs, a pedestrian wearing this device can walk with the same feeling as when he / she does not wear this device. In addition, the "assisting force" is added in addition to the "compensating force", so that the pedestrian can feel that the walking is assisted by the device.

FIG. 6 shows how the assisting force applied to the hip joint is determined and applied with respect to the walking time. The leg is out of bed and the first angle θ ₁ is 0 ° or more 10
Or less, and the walking speed v is a predetermined speed v ₀ = 2.0 [k
In the time zone R of m / h or more, in addition to the compensation force (thick line), the assisting force (thin line) is applied. On the other hand, time zone R
Only the compensation power (thick line) is given in the time zone except.

Then, unless the operation of the apparatus is stopped (NO in s7), the above-mentioned processes (s1 to s6) are repeatedly executed.

According to the present apparatus, when the legs are out of bed, the first
Only when the angle θ ₁ is 0 ° to + 10 ° (time zone R in FIG. 6), the assisting force (thin line in FIG. 6) is applied in addition to the compensating force (thick line in FIG. 6) (s2 in FIG. 6). In this case, according to the knowledge of the inventor of the present application, the thigh of the leg is swung forward due to the inertial force, and the muscular force of the pedestrian is hardly used for this swing. Therefore, according to the present device, since the assisting force is applied to the leg while the muscle force is hardly used, it is possible to avoid a situation in which the applying of the assisting force causes a decrease in the muscle force.

Here, in FIG. 7, the θ ₁ -θ ₂ locus (solid line) over one walking cycle when only the compensating force is applied, and the first angle θ ₁ of the leg in the awake state are 0 ° to + 10 °. Within a range (enclosed by the one-dot chain line) θ over one gait cycle when an auxiliary force is applied in addition to the compensation force
_1- θ ₂ locus (dotted line) is shown. The first angle theta ₁ of the legs of the lifting state is compared with both trajectories is substantially the same trajectory in the range of 0 ° ~ + 10 °, it is substantially the same shape as a whole. This is when the user is out of bed and the first angle θ ₁ is 0 ° to +
Even if the assisting force is applied to the leg within the range of 10 °, the posture of the leg is maintained as compared with the case where the assisting force is not applied, and the pedestrian is forced to walk in an unnatural posture. Means that can be avoided.

Furthermore, the walking speed v is 2.0 [km / km
h]) (time zone except time zone R in FIG. 6), no assisting force is applied (FIG. 2 s4, s5b). Walking speed v
Is less than 2.0 [km / h], it is set so that the pedestrian is assumed to walk intentionally slowly. Therefore, the assisting force is applied to the legs to increase the stride. It is possible to avoid a situation in which a pedestrian is forced to walk against his / her will. The value of 2.0 [km / h] may be changed and set as appropriate.

In this embodiment, the walking speed v and the first angle θ ₁
Although the conditions for applying the assisting force are specified by (see FIGS. 2s3 and 2s).
4), as another embodiment, in addition to these, the second angle θ ₂ , the inclination angle of the upper body, and the hip joint angular velocity ω ₁ = dφ ₁ /
The condition may be determined by dt and the knee joint angular velocity ω ₂ = dφ ₂ / dt.

In the present embodiment, the walking speed v was measured according to the above equation (3), but as another embodiment, the hip joint angular speed ω ₁ = dφ ₁ / dt and the knee joint angular speed ω ₂ = dφ ₂ / dt.
May be measured based on the outputs of the hip joint angle sensor 66 and the knee joint angle sensor 67, and then the walking speed v may be measured according to the following equation (4). As described above, the hip joint angular velocity ω ₁ is defined as positive when the thigh moves in the walking direction and negative when the thigh moves in the opposite direction to the walking direction. Further, the knee joint angular velocity ω ₂ is defined as a negative direction in which the knee joint extends and a positive direction in which the knee joint bends.

V = l ₁ ω ₁ · cos θ ₁ + l ₂ ω ₂ · cos θ ₂ (4)

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of a walking assist device according to an embodiment.

FIG. 2 is a flowchart showing a control method of the walking assistance device according to the present embodiment.

FIG. 3 is an explanatory diagram of a walking speed measuring method in the walking assist device of the present embodiment.

FIG. 4 is a flowchart showing a leg state determination method in the walking assistance device of the present embodiment.

FIG. 5 is an explanatory diagram of an assisting force determination method by the walking assist device of the present embodiment.

FIG. 6 is an explanatory diagram of assisting force by the walking assist device of the present embodiment.

FIG. 7 is a first angle θ in the walking assistance device according to the present embodiment.
_1- Second angle θ ₂ plane trajectory diagram

[Explanation of symbols]

11 ... Hip joint actuator, 12 ... Knee joint actuator, 2 ... Control unit, 21 ... Leg state determination means, 2
21 ... First angle measuring means, 222 ... Second angle measuring means,
223 ... Hip joint angular velocity measuring means, 224 ... Walking speed measuring means, 231, ... First storage means, 232 ... Second storage means,
24 ... Auxiliary force determining means, 66 ... Hip joint angle sensor, 67
... Knee joint angle sensor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hisashi Kato             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory

Claims (4)

[Claims] 1. A device for assisting the walking of a pedestrian by applying an assisting force to the pedestrian's leg through an actuator, wherein the pedestrian's leg is in a landing state or a floor leaving state. Leg condition determining means for determining which is the first angle measuring means for measuring the tilt angle of the pedestrian's thigh with respect to the vertical direction as the first angle, and walking speed for measuring the walking speed of the pedestrian. With respect to the leg that is determined to be in the bed leaving state by the leg state determination unit, the actuator is controlled so that the leg is provided with a compensating force for compensating the load caused by the use of the device. The assisting force is provided only when the first angle measured by the 1-angle measuring means is in the range of 0 ° to + 10 ° and the walking speed measured by the walking speed means is 2.0 [km / h] or more. Actuated to be applied to the leg Walking assist device, characterized in that a control means for controlling over data. 2. A hip joint angular velocity measuring means for measuring a hip joint angular velocity of a leg of a pedestrian, wherein the leg state determining means has a positive first angle measured by the first angle measuring means for one leg. The hip joint angular velocity measured by the hip joint angular velocity measuring means is equal to or more than a predetermined positive angular velocity, and the first angle measured by the first angle measuring means of the other leg is negative and the hip joint measured by the hip joint angular velocity measuring means. The walking assist device according to claim 1, wherein when the angular velocity is equal to or lower than a predetermined negative angular velocity, it is determined that the one leg is in a bed-leaving state and the other leg is in a landing state. 3. A second angle measuring means for measuring an inclination angle of a pedestrian's shin with respect to the vertical direction as a second angle, and a first storing means for storing and holding the lengths of the pedestrian's thigh and shin. The walking speed measuring means includes the lengths of the thighs and shins stored in the first storage means, the first angle measured by the first angle measuring means, and the second angle measuring means. The walking assist device according to claim 1, wherein the walking speed of the pedestrian is measured based on the measured second angle. 4. A second storage means for storing and holding a correlation between a walking speed of a pedestrian and an assisting force applied to a leg of the pedestrian, and a walking speed measured by the walking speed measuring means. And an assisting force determining unit that determines an assisting force applied to the leg via the actuator based on the correlation stored and held by the second storage unit. The walking assist device according to 1, 2, or 3.