JP5783455B2 - Walking support device - Google Patents

Description

  The present invention relates to a walking support device, for example, a device that assists walking.

In recent years, wearable robots (power assist suits) that assist muscle strength used for human movement (walking, lifting, etc.) have been developed mainly in the nursing care business.
There are various types of wearable robots such as those that assist the muscle strength of the upper body, those that assist the muscle strength of the lower body, and those that assist the muscle strength of the whole body.
In addition, the use of the wearable robot ranges from a healthy person to an elderly person / person with a disability.

  The wearable robot, for example, analyzes the movement of the muscle from the electromyogram of the wearer or analyzes the movement of the wearer detected by the posture sensor arranged in each part of the joint, thereby obtaining the joint moment necessary for the movement. The necessary assist force corresponding to this is generated. Thus, the wearer can easily lift and walk heavy objects.

As such a technique, there is “a wearable movement assist device, a control method of a wearable movement assist device, and a control program” in Patent Document 1.
In this technique, a biological signal is detected by a sensor installed on the wearer, and the actuator is used to generate power according to the wearer's intention.

By the way, human elbow joints and knee joints have complicated structures, and if these joint portions of the wearable robot are double joints, the followability of the wearer to the joint motion can be improved.
Each figure of FIG. 9 is a figure for demonstrating the conventional double joint drive mechanism.
As shown in FIG. 9A, the upper thigh connecting member 26 to be worn on the wearer's upper thigh and the lower thigh connecting member 27 to be worn on the lower thigh are a double joint having an interlocking gear 54 and gear 56. It joins via the part 50. FIG.
The knee joint assist actuator 18 includes a rod drive unit 64 and a rod 63, and the rod drive unit 64 is pivotally supported on the crotch side of the upper thigh coupling member 26 (the front side of the upper thigh). On the other hand, the tip of the rod 63 is pivotally supported by a member 100 that extends toward the upper thigh connection member 26 on the shin side (front side of the lower thigh) of the lower thigh connection member 27.

When the knee joint assist actuator 18 is driven in the double joint portion 50 configured as described above and the rod driving portion 64 pushes out the rod 63, the double joint portion 50 causes the upper leg connecting member 26 and the lower leg connecting member 27 to be driven. Bends as shown in FIG.
Further, when the rod driving unit 64 pushes out the rod 63, the upper thigh connecting member 26 and the lower thigh connecting member 27 are in a state in which the knees are folded as shown in FIG. 9C.
On the contrary, when the rod driving unit 64 retracts the rod 63, the upper thigh connecting member 26 and the lower thigh connecting member 27 are in a state where the knees are extended as shown in FIG. 9A, and the bending is released.

Each figure of FIG. 10 is a figure for demonstrating the other example of the conventional double joint drive mechanism.
In this example, as shown in FIG. 10A, the rod drive unit 64 is pivotally supported on the back side of the crotch side of the upper thigh connection member 26, and the tip of the rod 63 is connected to the lower thigh connection member 27. Is supported by a member 101 fixed to the shin side.
When the knee joint assist actuator 18 is driven in the double joint portion 50 configured as described above and the rod drive portion 64 retracts the rod 63, as shown in FIG. When the lower leg connecting member 27 is bent and the knee joint assist actuator 18 is further driven, the upper leg connecting member 26 and the lower leg connecting member 27 are further bent and the knee is broken as shown in FIG. It becomes.
Conversely, when the rod drive unit 64 pushes out the rod 63, the upper thigh connecting member 26 and the lower thigh connecting member 27 are in a state where the knees are extended as shown in FIG.

Conventionally, the double joint portion 50 is driven as described above. With this drive mechanism, for example, the knee joint assist actuator 18 is operated by the same amount in a state where the knee is extended and bent. Even so, the joint motion amount and joint motion torque are different.
That is, the joint operation torque and the joint operation speed per unit actuator operation amount differ depending on the knee flexion angle.
Thus, although the double joint part 50 has an excessive fluctuation characteristic, there was a problem that this characteristic is not necessarily suitable for walking assist.

JP 2005-95561 A

  An object of the present invention is to realize an excessive fluctuation characteristic suitable for walking assist in a double joint.

(1) In the first aspect of the invention, the first support member that is pivotally supported by the first support member that supports the upper leg of the walking support target person and that corresponds to the knee joint of the upper leg is formed. A second tooth part fixed to a second support member that supports a tooth part and a lower leg part joined to the knee joint, and meshes with and interlocks with the first tooth part; and A walking comprising: a rotating shaft and a tooth holding member that pivotally supports the rotating shaft of the second tooth portion, and driving means that drives and rotates the first tooth portion. A support device is provided.
(2) In the invention according to claim 2, one end of the driving means is pivotally supported by the first support member, and the other end is pivotally supported by the first tooth portion. The walking support device according to claim 1, wherein the walking support device extends and contracts in a rotation direction of the tooth portion.
(3) In the invention described in claim 3, the other end of the driving means is pivotally supported by an arm member fixed to the first tooth portion. A walking support device is provided.

  According to the present invention, an excessively variable characteristic suitable for walking assist is realized by decentering and driving a double-joint gear.

It is the figure which showed the mounting state of the mounting type robot. It is the figure which showed the system configuration | structure of the mounting | wearing type robot. It is a figure for demonstrating the mounting position of a double joint part. It is a figure for demonstrating in detail the structure of a double joint part. It is a figure for demonstrating the structure of a knee joint assist actuator, and operation | movement of a double joint part. It is a figure for demonstrating the joint operation torque and the joint operation speed per unit actuator operation amount. It is a figure for demonstrating an example of eccentricity of a gearwheel. It is a figure for demonstrating the other example of eccentricity of a gearwheel. It is a figure for demonstrating a prior art example. It is a figure for demonstrating a prior art example.

(1) Outline of Embodiment In the double joint portion 50 (FIG. 4), the gear 54 is rotatably supported by the lower leg connecting member 27 of the upper leg connecting member 26, and the gear 56 is supported by the lower leg connecting member 27. It is fixed so that it does not rotate.
The joint frame 52 rotatably supports the gear 54 and the gear 56, and holds the gear 54 and the gear 56 at a position where the tooth portions of the gear 54 and the gear 56 are engaged with each other.
A connecting arm 61 is fixed in a radial direction on the surface of the gear 54, and the connecting arm 61 is pivotally supported on a rod 63 by a connecting shaft 62. Although not shown, the rod 63 constitutes the knee joint assist actuator 18 and moves in the axial direction.
Therefore, when the knee joint assist actuator 18 is driven, the gear 54 is rotated by the rod 63, the gear 56 is rotated in conjunction with this, and the lower leg connecting member 27 is bent with respect to the upper leg connecting member 26.

As shown in FIG. 7A, the rotation shafts of the gear 54 and the gear 56 are eccentrically supported by the same offset amount.
For this reason, when the gear 54 is driven, the gear ratio between the gear 54 and the gear 56 continuously changes in a stepless manner. As a result, the joint operation torque, the joint operation speed, and the joint operation amount per unit actuator operation amount also change continuously.
By using this, the double joint portion 50 is set by variously setting the eccentric offset amount of the gear 54 and the gear 56, the initial angle of the connecting arm 61, and the position of the connecting shaft 62 (distance from the rotation center to the connecting shaft 62). Can be adjusted. Therefore, the characteristics of the double joint portion 50 can be optimized at a low cost in accordance with the motion characteristics of the wearer's legs.

(2) Details of Embodiment FIG. 1 is a diagram showing a mounting state of the mounting robot 1.
The wearable robot 1 is worn on the waist and lower limbs of the wearer to assist (assist) the wearer's walking.
The wearable robot 1 includes a waist attachment part 21, an upper leg attachment part 22, a lower leg attachment part 23, a foot attachment part 24, an upper leg connection member 26, a lower leg connection member 27, a control device 2, a toe reaction force sensor 10, Force sensor 11, toe posture sensor 12, heel posture sensor 13, waist posture sensor 14, upper leg posture sensor 15, lower leg posture sensor 16, hip joint assist actuator 17, knee joint assist actuator 18, ankle joint assist actuator 19 and the like are provided. Yes. In addition, except for the waist mounting part 21, the control device 2, and the waist posture sensor 14, they are provided on both the left and right feet, and the respective detected values are output.
However, the toe reaction force sensor 10 and the heel reaction force sensor 11 may be provided with a toe grounding sensor and a heel grounding sensor instead of both sensors in the embodiment in which the detection of the reaction force is unnecessary. .

The waist mounting portion 21 is attached around the waist of the wearer and fixes the wearable robot 1.
The waist posture sensor 14 is attached to the waist attachment portion 21 and detects the posture of the waist (roll angle, yaw angle, pitch angle) with a gyroscope or the like. Also, by differentiating these angles, the angular velocity and angular acceleration of the waist can be obtained.

The control device 2 is attached to the waist mounting portion 21 and controls the operation of the wearable robot 1.
The hip joint assist actuator 17 is provided at the same height as the hip joint of the wearer, and drives the upper thigh coupling member 26 in the front-rear direction with respect to the waist mounting portion 21. Note that the hip joint assist actuator 17 may be configured to be driven in the lateral direction as a three-axis actuator.

The upper thigh coupling member 26 is a rigid columnar member provided outside the upper thigh of the wearer, and is fixed to the upper thigh of the wearer by the upper thigh mounting portion 22. The upper thigh connecting member 26 is driven by the hip joint assist actuator 17 to support the movement of the upper thigh.
The outer side of the upper thigh mounting part 22 is fixed to the inner side of the upper thigh coupling member 26, and the inner side is fixed to the upper leg of the wearer.
The upper leg posture sensor 15 detects the upper leg posture (roll angle, yaw angle, pitch angle). In addition, by differentiating these angles, the angular velocity and acceleration of the upper thigh can be obtained.

The knee joint assist actuator 18 drives a double joint portion 50, which will be described later, formed at the knee joint portion, thereby moving the lower leg connecting member 27 in the front-rear direction to support the movement of the lower leg portion of the wearer.
The crus connecting member 27 is a columnar member having rigidity provided outside the crus of the wearer, and is fixed to the crus of the wearer by the crus attachment 23. The lower leg connecting member 27 is driven by the knee joint assist actuator 18 to support the movement of the lower leg.

The outer side of the lower leg mounting portion 23 is fixed to the inner side of the lower leg connecting member 27, and the inner side is fixed to the lower leg of the wearer.
The lower leg posture sensor 16 detects the lower leg posture (roll angle, yaw angle, pitch angle). Also, by differentiating these angles, the angular velocity and angular acceleration of the lower leg can be obtained.

The ankle joint assist actuator 19 is provided at the same height as the wearer's ankle joint, and drives the toe of the foot mounting portion 24 in the direction of moving up and down with respect to the crus coupling member 27.
The foot mounting portion 24 is fixed to the foot portion (instep and sole) of the wearer. Generally, the joint at the base of the toe is bent during walking, but the foot mounting portion 24 is also configured so that the base of the toe is bent according to the toes.

  The toe posture sensor 12 and the heel posture sensor 13 are respectively installed at the front end and the rear end of the foot mounting portion 24 and detect the toe and heel postures (roll angle, yaw angle, pitch angle), respectively. Further, by differentiating these angles, the angular velocity and angular acceleration of the toes and the heel can be obtained.

The toe reaction force sensor 10 is installed in front of the sole portion of the foot mounting portion 24 and detects the ground contact of the toe and the reaction force from the walking surface.
The heel reaction force sensor 11 is installed on the rear side of the sole of the foot mounting portion 24 and detects the ground contact of the heel and also detects the reaction force from the walking surface.
The wearable robot 1 configured as described above supports the walking of the wearer by driving the hip joint assist actuator 17, the knee joint assist actuator 18, and the ankle joint assist actuator 19.

FIG. 2 is a diagram showing a system configuration of the wearable robot 1.
The control device 2 includes an electronic control unit including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a clock as means for measuring time, a storage unit 7, various interfaces, and the like. And each part of the wearable robot 1 is electronically controlled.

The control device 2 is also configured by executing various programs such as a walking support program stored in the storage unit 7 by the CPU, and includes a sensor information acquisition unit 3, various parameter calculation units 4, a walking motion determination unit 5, A walking scene determination unit 6 and a walking assist force determination unit 8 are provided.
The sensor information acquisition unit 3 acquires a detection value from each of the toe reaction force sensor 10 to the crus posture sensor 16. The detection value of each sensor acquired by the sensor information acquisition unit 3 is used for determination of walking motion, determination of a walking scene, calculation of walking parameters, and the like.

The various parameter calculation unit 4 calculates walking parameter values (overlapping pace and overlapping walking distance) by obtaining the angles and positions of the joints from the detection values acquired by the sensor information acquisition unit 3.
Here, an operation from the contact of one side of the heel to the contact of the next side of the heel is referred to as an overlapping step, and a series of operations in the overlapping step is referred to as a walking cycle. The distance between the two ground contact points in the overlapping step is referred to as the overlapping step distance, and the number of overlapping steps per minute (the number of overlapping steps / minute) is referred to as the overlapping step.

The walking motion determination unit 5 determines whether the wearer's motion is a motion other than walking such as a bending / stretching motion or a stepping motion, or an actual walking motion.
The walking scene determination unit 6 determines a walking scene in which the wearer is walking from the detection value acquired by the sensor information acquisition unit 3. There are two types of walking scenes that can be judged: walking direction (flat, upstairs, downstairs, uphill, downhill) for each of the five walking directions of forward walking and backward progress. There are 10 walking scenes.

  The walking assist force determining unit 8 determines the assist force to be output to the hip joint assist actuator 17, the knee joint assist actuator 18, and the ankle joint assist actuator 19 disposed on the left and right feet, and drives these assist actuators accordingly. . The assist force is a moment (torque) that the wearable robot 1 drives the assist actuator to act on the legs.

FIG. 3 is a view for explaining the mounting position of the double joint portion 50. FIG. 3A shows a front view, and FIG. 3B shows a side view.
In FIG. 3 (a), only the right foot is attached to simplify the drawing, but it is attached to both feet. Further, the knee joint assist actuator 18 is omitted.
The double joint portion 50 is formed corresponding to the position of the knee joint of the wearer, and joins the lower end of the upper thigh connection member 26 and the upper end of the lower thigh connection member 27.
The double joint portion 50 has a circular gear 54 pivotally supported on the lower end side of the upper thigh connection member 26, a circular gear 56 fixed on the upper end side of the lower thigh connection member 27, and the gear 54 and the gear 56. A supporting joint frame 52 is provided.
The gear 54 and the gear 56 are interlocked with each other by meshing tooth portions (gears).

  When the wearer bends the knee, the double joint portion 50 is bent accordingly. Then, the rotation center of the lower leg connecting member 27 with respect to the upper leg connecting member 26 is the intersection of the axes of the upper leg connecting member 26 and the lower leg connecting member 27, and moves forward as the knee bends. This movement is well adapted to the movement of the knee of the human body, and the double joint portion 50 can follow the knee back and forth motion well.

FIG. 4 is a view for explaining the structure of the double joint portion 50.
In the double joint portion 50 of the present embodiment, the rotation shafts of the gear 54 and the gear 56 are eccentric. First, the case where the gear 54 and the gear 56 are not eccentric will be described. A case where the gear 56 is eccentric will be described.
A gear 54 is rotatably supported by a fixed shaft 55 on the lower end side of the upper thigh connection member 26 (lower thigh connection member 27 side).
Although not shown, teeth are formed on the entire circumference of the gear 54. The tooth portion does not need to be formed on the entire circumference of the gear 54, and may be formed at least at a portion that meshes with the gear 56.

On the other hand, the gear 56 is fixed to the upper end side (upper thigh connection member 26 side) of the crus coupling member 27 by the fixing shaft 57 and the fixtures 60, 60, 60 provided around the fixing shaft 57 every 120 degrees. Has been. In addition, in order to avoid complication of a figure, the fixing tool 60 attaches | subjects the code | symbol to only one.
Since the rotation of the gear 56 with respect to the crus connection member 27 is restricted by the fixture 60, the gear 56 does not rotate with respect to the crus connection member 27 and moves together with the crus connection member 27.
Although not shown, teeth are formed on the entire circumference of the gear 56. The tooth portion does not need to be formed on the entire circumference of the gear 56, and may be formed at least at a portion that meshes with the gear 54.

The joint frame 52 is a plate-like member, and the gear portion 54 and the tooth portion of the gear 56 are engaged with each other, and the gear 54 and the fixed shaft 55 are pivotally supported at positions where they are interlocked with each other.
For this reason, when the gear 54 rotates with respect to the joint frame 52, the gear 56 also rotates with respect to the joint frame 52. Since the gear 56 is fixed to the crus connecting member 27, the crus connecting member 27 rotates with respect to the crus connecting member 26.

  In FIG. 4, the joint frame 52 is disposed only on one side of the gear 54 and the gear 56, but the joint frame 52 is also provided on the opposite one side, and the gear 54 and the gear 56 are connected by the two joint frames 52. It may be sandwiched. Furthermore, when the two joint frames 52 are connected and fixed to each other, the strength of the double joint portion 50 can be improved.

The connecting arm 61 is fixed to the surface of the gear 54 and extends to the outside of the gear 54 in the radial direction of the gear 54.
The distal end portion of the rod 63 is pivotally supported by the coupling shaft 62 at the distal end portion of the coupling arm 61.
When the rod 63 expands and contracts, a force is transmitted to the gear 54 via the connecting arm 61, and a torque for rotating the gear 54 is generated.

  When the gear 54 is rotated by the torque generated by the rod 63, the gear 56 is rotated in conjunction with it, whereby the lower leg connecting member 27 is rotated with respect to the upper leg connecting member 26. In this way, by driving the rod 63, the double joint portion 50 can be driven, and the crus coupling member 27 can be rotated and bent.

Each drawing in FIG. 5 is a diagram for explaining the configuration of the knee joint assist actuator 18 and the operation of the double joint portion 50.
Fig.5 (a) has shown the double joint part 50 in the state which the knee extended.
The knee joint assist actuator 18 expands and contracts by inserting and removing the rod 63 from the rod driving unit 64 in the axial direction.
For example, a ball screw, hydraulic pressure, pneumatic pressure, artificial muscle (for example, McKibben type) or the like can be used for the rod driving unit 64.
An end portion of the rod driving portion 64 is pivotally supported on the crotch side of the upper thigh coupling member 26 by a coupling shaft 65. For this reason, the knee joint assist actuator 18 can freely change the attachment angle with respect to the upper thigh coupling member 26 according to expansion and contraction.

When the knee joint assist actuator 18 is operated and the rod driving unit 64 pulls the rod 63, the length of the knee joint assist actuator 18 is shortened as shown in FIG.
Then, since the rod drive unit 64 is pivotally supported by the upper thigh connection member 26, the connection arm 61 is drawn toward the rod drive unit 64 side and the gear 54 rotates, and the gear 56 and the gear 54 are interlocked with this. Rotate in the opposite direction.
Since the gear 54 is fixed to the crus connecting member 27, the crus connecting member 27 rotates in a direction in which the knee is bent with respect to the crus connecting member 26. In this way, the double joint portion 50 is driven by the knee joint assist actuator 18.

Further, when the rod drive unit 64 retracts the rod 63, the lower leg connecting member 27 rotates to an angle at which the knee is bent with respect to the upper leg connecting member 26 as shown in FIG.
Conversely, when the rod drive unit 64 sends out the rod 63, the upper thigh connecting member 26 and the lower thigh connecting member 27 are in a state where the knees are extended as shown in FIG.

Each diagram in FIG. 6 is a diagram for explaining the joint operation torque and the joint operation speed per unit actuator operation amount.
As shown in FIG. 6A, the center of the fixed shaft 55 is the origin, the x-axis is from the origin toward the center of the gear 56, and the direction of the rod 63 (more specifically, the connecting shaft 62 is farthest from the x-axis). Direction) is set to the y-axis.
When the knee joint assist actuator 18 is driven to move the rod 63 in the x-axis direction, the gear 54 rotates around the origin.

Now, as shown in the figure, the angle formed by the y-axis and the connecting arm 61 is θ. An input possible angle θ, that is, an angle at which the double joint portion 50 can be mechanically moved without considering the knee structure of the human body is β (from −β / 2 to β / 2), and a necessary joint driving angle, The angle required to assist the knee motion is α (from −α / 2 to α / 2). When θ = α / 2, the knee is stretched.
The input possible angle and the required joint drive angle are examples. The input possible angle is from β1 to β2, the required joint drive angle is from α1 to α2, and the configuration of the double joint portion 50 and the connecting arm 61. Various values can be taken depending on the reference mounting angle. The larger the θ is, the smaller the joint angle is (when the knee is extended), and the smaller θ is, the larger the joint angle is (when the knee is bent).

FIG. 6B plots the torque per unit actuator operation amount at each θ, that is, the value of the torque that the connecting arm 61 acts on the gear 54 when the rod 63 is driven by the unit amount over each θ. Is.
As shown in the figure, the torque increases as θ approaches 0 (away from the x-axis), and decreases as the absolute value of θ increases (closer to the x-axis).

FIG. 6 (c) plots the joint operation speed per unit actuator operation amount at each θ, that is, the speed at which the connecting arm 61 rotates the gear 54 when the rod 63 is driven by the unit amount over each θ. It is a thing.
As shown in the figure, the torque decreases as θ approaches 0 (away from the x-axis), and increases as the absolute value of θ increases (closer to the x-axis).
The joint movement amount per unit actuator movement amount has the same characteristics.

  Thus, since the torque and the joint operation speed (and the joint operation amount) change according to θ, for example, when the connecting arm 61 and the connecting shaft 62 are installed at a position where the rod 63 is further extended (position where θ is large), In a portion where the joint flexion angle is small, the joint operation speed per unit actuator operation amount decreases and the joint operation torque increases. Further, in a portion where each joint bending angle is large, the joint operation speed per unit actuator operation amount increases and the joint operation torque decreases.

  On the contrary, when the connecting arm 61 and the connecting shaft 62 are installed at a position where the knee joint assist actuator 18 is further contracted (position where θ is small), the joint operation speed per unit actuator operation amount increases at a portion where the joint bending angle is small. And the joint operating torque becomes smaller. Further, in a portion where each node bending angle is large, the joint operation speed per unit actuator operation amount decreases and the joint operation torque increases.

Thus, since the double joint part 50 has a variation excessive characteristic depending on the attachment position of the connecting arm 61, for example, the knee joint assist actuator 18 is suitable for walking support according to the variable fluctuation characteristic of the double joint part 50. The excessive fluctuation characteristics are not necessarily suitable for walking support, such as the necessity of having output characteristics or the possibility of an overload acting on the connecting arm 61.
Therefore, in the present embodiment, the excessive fluctuation characteristics are made more suitable for walking assistance by decentering the rotation axes of the gear 54 and the gear 56.

Each drawing in FIG. 7 is a diagram for explaining an example of eccentricity of the gear 54 and the gear 56.
As shown in FIG. 7A, in the gear 54, the fixed shaft 55 (center of rotation) is offset from the center of the gear 54 in the -x direction at the position t, and the gear 56 is also connected to the fixed shaft 57 ( The center of rotation) is offset from the center of the gear 56 to the position t in the -x direction.
Thus, the gear 54 and the gear 56 are eccentrically supported by the same amount in the same direction and are pivotally supported by the joint frame 52 (not shown). And since the gear 54 and the gear 56 have the same diameter, even if it decenters in this way, they can mesh and rotate.

The angle β indicates an inputtable angle of θ. The necessary joint driving angle α is the same as that in FIG. 6A and is omitted to avoid complication of the drawing.
Since the gear 54 and the gear 56 are eccentric, the gear ratio between the gear 54 and the gear 56 continuously changes as the gear 54 rotates.
When the radius of the gear 54 increases as the connecting arm 61 rotates, the gear ratio increases because the radius of the gear 56 decreases.

On the contrary, when the radius of the gear 54 becomes smaller as the connecting arm 61 rotates, the gear ratio becomes smaller because the radius of the gear 56 becomes larger.
For example, when the connecting arm 61 is in the position shown in FIG. 7A, the gear ratio is the maximum because the radius of the gear 54 is the maximum, and the connecting arm 61 can be rotated to any side. Gear ratio decreases.

7B, the torque per unit actuator operation amount at each θ when the rotating shafts of the gear 54 and the gear 56 are eccentric as shown in FIG. 7A, that is, the rod 63 is driven by the unit amount. In this case, the torque value that the connecting arm 61 acts on the gear 54 is plotted over each θ.
As shown in the figure, the torque changes as the distance between the x-axis and the connecting shaft 62 changes, and the gear ratio also changes.

FIG. 7C shows a joint operation speed per unit actuator operation amount at each θ when the rotation axes of the gears 54 and 56 are eccentric as shown in FIG. The speed at which the connecting arm 61 rotates the gear 54 when driven is plotted over each θ.
As shown in the figure, the joint operation speed is a combination of these effects because the distance between the x-axis and the connecting shaft 62 is changed and the gear ratio is changed.

Each drawing of FIG. 8 is a diagram for explaining another example of the eccentricity of the gear 54 and the gear 56.
As shown in FIG. 8A, in the gear 54, the fixed shaft 55 is offset from the center of the gear 54 to the position t in the + x direction. In the gear 56, the fixed shaft 57 is moved from the center of the gear 56. It is offset from the position of t in the + x direction.
Thus, the gear 54 and the gear 56 are eccentrically supported by the same amount in the same direction and are pivotally supported by the joint frame 52 (not shown). And since the gear 54 and the gear 56 have the same diameter, even if it decenters in this way, they can mesh and rotate.

The angle β indicates an inputtable angle of θ. The necessary joint driving angle α is the same as that in FIG. 6A and is omitted to avoid complication of the drawing.
Since the gear 54 and the gear 56 are eccentric, the gear ratio between the gear 54 and the gear 56 continuously changes as the gear 54 rotates.
When the radius of the gear 54 increases as the connecting arm 61 rotates, the gear ratio increases because the radius of the gear 56 decreases.

On the contrary, when the radius of the gear 54 becomes smaller as the connecting arm 61 rotates, the gear ratio becomes smaller because the radius of the gear 56 becomes larger.
For example, when the connecting arm 61 is in the position shown in FIG. 8A, the gear ratio is minimum because the radius of the gear 54 is minimum, and the connecting arm 61 can be rotated to any side. Gear ratio increases.

In FIG. 8B, the torque per unit actuator operation amount at each θ when the rotating shafts of the gear 54 and the gear 56 are eccentric as shown in FIG. 8A, that is, the rod 63 is driven by a unit amount. In this case, the torque value that the connecting arm 61 acts on the gear 54 is plotted over each θ.
As shown in the figure, the torque changes as the distance between the x-axis and the connecting shaft 62 changes and the gear ratio also changes.

FIG. 8C shows a joint operation speed per unit actuator operation amount at each θ when the rotation axes of the gears 54 and 56 are eccentric as shown in FIG. The speed at which the connecting arm 61 rotates the gear 54 when driven is plotted over each θ.
As shown in the figure, the joint operation speed is a combination of these effects as the distance between the x-axis and the connecting shaft 62 changes and the gear ratio also changes.

The example of the eccentricity of the gear 54 and the gear 56 has been described above. By decentering the gear in the double joint portion 50 in this manner, for example, when the joint angle is large (the joint is greatly bent), the gear ratio is increased. The gear ratio can be varied steplessly, such as when the required torque is output, or when the joint angle is small (the joint is extended), and the gear ratio is reduced to increase the operating speed. It becomes possible to match the characteristics of movement.
Further, depending on the magnitude of the eccentricity, the mounting angle of the connecting arm 61 in the initial state (the state where the knees are extended), and the distance from the rotation center to the connecting shaft 62, the fluctuation excessive characteristics (unit actuator operation amount). (Torque and joint operation speed) can be adjusted in more detail.
Thus, in the double joint portion 50, the characteristics can be adjusted by mechanical specifications, so that it is possible to obtain both the maximum generated torque and the operation speed of the knee joint assist actuator 18 at low cost.

The double joint portion 50 of the present embodiment has been described above, but the following effects can be obtained thereby.
(1) By decentering the gear 54 and the gear 56 in the double joint portion 50, the gear ratio between the gear 54 and the gear 56 can be continuously changed as the gear 54 rotates.
(2) In the double joint portion 50, various excessive fluctuation characteristics can be realized depending on the amount of eccentricity of the gear 54 and the gear 56 and the attachment angle of the connecting arm 61. For this reason, the double joint part 50 can be comprised so that it may have the characteristic match | combined with the exercise | movement characteristic of the actual leg part at low cost.
(3) By driving the gear 54 installed in the double joint portion 50, the stroke of the knee joint assist actuator 18 necessary for the joint operation can be shortened. Therefore, a linear actuator with a short stroke can be used as the knee joint assist actuator 18. Further, the attachment position of the knee joint assist actuator 18 is not greatly offset, and the protrusion around the joint is eliminated. Thus, the drive mechanism of the double joint portion 50 can be reduced in size.
(4) In the conventional example shown in FIG. 9, (a) the required stroke of the knee joint assist actuator 18 is long, (b) the variation of the joint operation angle per unit actuator operation amount is large, and the operation is performed as the bending angle increases. The amount of actuator movement per angle is reduced, and it is difficult to generate joint torque at a portion where the bending angle is large. (C) The actuator pivot protrudes and projects at the apex of the knee, so the pivot that is the point of action can contact the obstacle. However, in this embodiment, these problems can be significantly reduced.
(5) In the conventional example shown in FIG. 10, (a) the required stroke of the knee joint assist actuator 18 is long, and (b) the knee joint assist actuator 18 overhangs inside the joint when bent, making it difficult to sit on a chair. However, in this embodiment, these problems can be significantly reduced.

According to the embodiment described above, the following configuration can be obtained.
(1) The upper thigh connecting member 26 functions as a first support member that supports the upper thigh of the walking support target, and the tooth portion of the gear 54 is pivotally supported by the first support member. It functions as a first tooth formed corresponding to the knee joint of the upper leg.
The crus coupling member 27 functions as a second support member that supports the crus joined to the knee joint, and the tooth portion of the gear 56 is fixed to the second support member, and the first teeth It functions as a second tooth portion that engages and interlocks with the portion.
In the joint frame 52, the rotation shafts of the gear 54 and the gear 56 are eccentric, and the joint frame 52 supports these rotation shafts. Therefore, the rotation shaft of the first tooth portion and the second tooth portion of the joint frame 52 are supported. It functions as a tooth | gear part holding member which eccentrically supports the rotating shaft of and supports.
The knee joint assist actuator 18 functions as a driving unit that drives and rotates the first tooth portion. The gear 54 may be driven by a motor instead of the knee joint assist actuator 18.
(2) The knee joint assist actuator 18 has the rod drive unit 64 side pivotally supported by the upper thigh coupling member 26 and the rod 63 side pivotally supported by the coupling arm 61 or directly by the gear 54. One end is pivotally supported by the first support member, the other end is pivotally supported by the first tooth portion, and expands and contracts in the rotation direction of the first tooth portion.
(3) When the rod 63 is pivotally supported by the gear 54 via the connecting arm 61, the connecting arm 61 functions as an arm member, and the other end of the driving means is connected to the first tooth portion. It is pivotally supported by a fixed arm member.

DESCRIPTION OF SYMBOLS 1 Wearable robot 2 Control apparatus 3 Sensor information acquisition part 4 Various parameter calculation part 5 Walking motion determination part 6 Walking scene determination part 7 Memory | storage part 8 Walking assist force determination part 10 Toe reaction force sensor 11 踵 Reaction force sensor 12 Toe posture sensor 13 Waist Posture Sensor 14 Waist Posture Sensor 15 Upper Leg Posture Sensor 16 Lower Leg Posture Sensor 17 Hip Joint Assist Actuator 18 Knee Joint Assist Actuator 19 Ankle Joint Assist Actuator 21 Lumbar Mount Part 22 Upper Thigh Mount Part 23 Lower Thigh Mount Part 24 Leg Mount Part 26 Upper Thigh connecting member 27 Lower thigh connecting member 50 Double joint portion 52 Joint frame 54 Gear 55 Fixed shaft 56 Gear 57 Fixed shaft 60 Fixing tool 61 Connecting arm 62 Connecting shaft 63 Rod 64 Rod driving portion 65 Connecting shaft 100 Member 101 Member

Claims (3)

A first tooth portion pivotally supported by a first support member that supports the upper leg of the walking support target person and formed corresponding to the knee joint of the upper leg;
A second tooth part fixed to a second support member that supports a lower leg part joined to the knee joint, and meshes with and interlocks with the first tooth part;
A tooth holding member that pivotally supports the rotating shaft of the first tooth portion and the rotating shaft of the second tooth portion by eccentrically,
Driving means for driving and rotating the first tooth portion;
A walking support device characterized by comprising:   One end of the driving means is pivotally supported by the first support member, the other end is pivotally supported by the first tooth portion, and extends and contracts in the rotation direction of the first tooth portion. The walking support device according to claim 1.   The walking support device according to claim 2, wherein the other end of the driving unit is pivotally supported by an arm member fixed to the first tooth portion.

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