JP2013208293A - Walking support device and walking support program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an unnatural feeling of an assist in a swing phase by releasing a clutch arranged in a knee joint in a swing phase.SOLUTION: A drive system of a leg connection member 27 and a transmission system for transmitting drive force by the drive system to the leg connection member 27 are connected or released with the use of a clutch 36. A region where the angular velocity of a knee joint is higher in walking is the section from immediately before a swing phase to near the end of a swing phase. In the period, a body has no necessity to be supported and assist force is not required. A region requiring assist force is mainly a first half of a stance phase and an angular velocity is lower in the period. A wearable robot 1 determines timing of a stance phase or a swing phase. A clutch 36 is separated in a swing phase so as to demonstrate required assist force in a stance phase and to eliminate an unnatural feeling in walking assistance in a swing phase.

Description

  The present invention relates to a walking support device and a walking support program, for example, to assisting a wearer's walking.

In recent years, wearable walking support devices that assist users in walking have been developed.
The walking support device assists the wearer's walking by reducing the joint moment required for walking at the hip joint, knee joint, ankle joint, and the like of the wearer with an actuator. In addition to supporting the walking of healthy people, the walking support device can support the walking of users who are difficult to walk, such as elderly people.

As such a technique, there is a “walking assisting device” of Patent Document 1.
In general, it is difficult to achieve both a period in which sufficient torque is required in the stance phase and a period in which the speed of the swing phase is high and the load is light, with a single actuator, and either torque or speed may be insufficient. High nature.
This technology compensates for the insufficient capacity of the actuator by generating the output of the stance phase by engaging the one-way clutch regardless of the output of the actuator.

  However, this technique has a problem that since the actuator is interlocked with the leg during the swinging leg period, the speed during the swinging leg period is insufficient, causing resistance during walking and causing discomfort.

JP 2011-142958 A

  An object of the present invention is to reduce the discomfort of assist during the swing leg period.

(1) In the invention according to claim 1, a holding means for holding the leg part of the walking support target, an assist force output means for outputting an assist force for assisting a joint moment generated at the joint of the leg part, There is provided a walking support device comprising: a transmission unit that transmits the output assist force to the holding unit; and an opening unit that releases transmission by the transmission unit.
(2) In the invention described in claim 2, the walking support device according to claim 1, wherein the joint is a knee joint.
(3) In the invention described in claim 3, the opening means releases the transmission in synchronization with the walking cycle, and provides the walking support device according to claim 1 or 2. .
(4) In the invention according to claim 4, the release means releases the transmission during a free leg period. The invention according to claim 1, 2, or 3 A walking support device is provided.
(5) In the invention described in claim 5, the assist force output function for outputting the assist force for assisting the joint moment generated at the joint of the leg of the walking support target, and the output assist force is held in the leg. Provided is a walking support program for realizing a transmission function for transmitting to a holding means and an opening function for releasing transmission by the transmission means by a computer.

  According to the present invention, by disengaging the clutch provided at the knee joint during the swing phase, it is possible to reduce the discomfort of the assist during the swing phase.

It is the figure which showed the mounting state of the mounting type robot. It is a figure for demonstrating a clutch mechanism. It is the figure which showed the system configuration | structure of the mounting | wearing type robot. It is a figure for demonstrating the area | region which operates a clutch. It is a flowchart for demonstrating the procedure which operates a clutch. It is a flowchart for demonstrating the procedure of an open determination process. It is a flowchart for demonstrating the procedure of a connection determination process.

(1) Outline of Embodiment A drive system (such as the knee joint assist actuator 18) of the crus coupling member 27 and a transmission system (such as the knee joint shaft 34) that transmits the driving force by the drive system to the crus coupling member 27 are a clutch. 36 can be connected or released (FIG. 2A).
As is clear from the graph of FIG. 4, the region where the angular velocity of the knee joint is fast when walking is from just before the swing phase to the end of the swing phase, and during this period, it is not necessary to support the body and assist force is applied. do not need. On the other hand, the region where the assist force is required is mainly in the first half of the stance phase, and the angular velocity is slow during this period.
Therefore, the wearable robot 1 determines the timing of the stance phase and the swing phase and disconnects the clutch 36 during the swing phase, thereby demonstrating the necessary assist force during the stance phase. Eliminates the effects of insufficient speed of the drive system and eliminates discomfort in walking assistance.

(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 is provided at the same height as the knee joint of the wearer, and moves the lower leg connection member 27 in the front-rear direction with respect to the upper leg connection member 26 to move the lower leg of the wearer. Support.
The knee joint assist actuator 18 is provided with a clutch 36 which will be described later, and the torque generated by the knee joint assist actuator 18 with respect to the crus coupling member 27 can be released and connected by a command from the control device 2. .

  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.

Each drawing in FIG. 2 is a view for explaining a clutch mechanism formed in the knee joint assist actuator 18.
As shown in FIG. 2A, the knee joint assist actuator 18 includes a knee joint motor 31, a rotation shaft 32, a bevel gear 33, a bevel gear 35, a knee joint shaft 34, a clutch 36, and the like.

The upper thigh connecting member 26 and the lower thigh connecting member 27 are connected by a knee joint shaft 34 so as to be rotatable in the front-rear direction.
For example, the knee joint shaft 34 is formed coaxially with the knee joint of the wearer so that the longitudinal motion of the lower leg connection member 27 with respect to the upper leg connection member 26 and the longitudinal motion of the lower leg with respect to the wearer's upper leg coincide with each other. . This is an example, and the upper thigh connecting member 26 and the lower thigh connecting member 27 may be joined by a double joint so as to be more adapted to the movement of the knee joint of the wearer.

The knee joint motor 31 is, for example, a DC motor, and generates torque necessary for assisting the knee joint, that is, assist force.
Normally, an advanced motor is required which can achieve both low-speed rotation and large torque in the stance phase and high-speed rotation and small torque in the swing phase as much as possible. Since the joint motor 31 is separated from the knee joint drive system, a lower cost motor can be used.

On the knee joint side of the knee joint motor 31, a rotation shaft 32 of the knee joint motor 31 protrudes, and a bevel gear 33 is formed at the tip portion thereof.
On the other hand, a bevel gear 35 that meshes with the rotary shaft 32 is formed on the knee joint shaft 34, and the torque of the knee joint motor 31 is converted into torque that rotates the knee joint shaft 34.
The bevel gear 35 is joined to the knee joint shaft 34 via the clutch 36, and the torque transmitted from the bevel gear 33 to the bevel gear 35 is transmitted to the knee joint shaft 34 by connecting and releasing the clutch 36. Can be cut (blocked).

FIG. 2 (b) is a view showing a state where the clutch 36 is in an open state.
The clutch 36 includes a knee joint shaft side disk 42, a bevel gear side disk 41, a disk moving member 43, and the like.
The knee joint shaft side disc 42 is a disk that is fixed relative to the knee joint shaft 34 in the rotational direction of the knee joint shaft 34 and is movable in the rotational axis direction of the knee joint shaft 34. A plurality of joint shafts 34 are formed coaxially with the knee joint shaft 34 in the rotation axis direction.

The bevel gear disc 41 is a disk that is fixed to the bevel gear 35 in the rotational direction of the bevel gear 35 and is movable in the rotational axis direction of the bevel gear 35. A plurality of sheets are formed.
The knee joint shaft side discs 42 and the bevel gear side discs 41 are alternately arranged, and are located at a predetermined distance from each other by a spring mechanism or the like when the clutch 36 is released.
As described above, when the clutch 36 is released, no friction is generated between the knee joint shaft side disk 42 and the bevel gear side disk 41, and the torque generated by the bevel gear 35 is not transmitted to the knee joint shaft 34.

FIG. 2 (c) is a view showing a state where the clutch 36 is in a connected state.
The knee joint shaft 34 is formed with a disk moving member 43 that presses the knee joint shaft side disk 42 toward the bevel gear side disk 41 when the clutch 36 is connected.
The disk moving member 43 presses the outermost knee joint axis side disk 42 toward the bevel gear side disk 41 when the clutch 36 is connected.

Then, the knee joint shaft side disk 42 and the bevel gear side disk 41 are sequentially moved from the outer side toward the bevel gear 35 and are brought into close contact with each other.
As a result, the knee joint shaft side disk 42 and the bevel gear side disk 41 are joined by frictional force, and the torque generated by the bevel gear 35 is transmitted to the knee joint shaft 34.

Thus, the clutch 36 can control transmission and release of the driving force using the disk moving member 43.
The clutch 36 is an example, and various clutches such as an electromagnetic clutch can be used.

FIG. 3 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, a walking assist force determination unit 8, and a clutch control unit 9 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 the stance period / swing period, determination of walking motion, determination of walking scene, calculation of walking parameters, and the like.

The various parameter calculation unit 4 calculates parameter values necessary for determination of the stance phase / swing phase, such as the angle and angular velocity of each joint, from the detection values acquired by the sensor information acquisition unit 3.
The stance period is a period in which the leg is grounded and kicks the ground backward, and the free leg period is a period in which the leg is lifted from the ground and returned to the front.
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 each assist actuator to act on the legs.
The clutch control unit 9 controls the connection and release of the clutch 36 by driving the disk moving member 43 (FIG. 2).

Each figure of FIG. 4 is a figure for demonstrating the area | region (section) which operates the clutch 36 in one walk cycle.
FIG. 4A is a graph showing the transition of the joint moment of the knee joint.
As is apparent from the graph, the walking cycle is composed of a stance phase and a swing phase, and a larger joint moment is generated in the knee joint in the stance phase than in the swing phase.
For example, in the stance phase, the maximum absolute value of the joint moment is about 40 (Nm), whereas in the swing phase, the absolute value is about 10 (Nm).

FIG. 4B is a graph showing changes in the angular velocity of the knee joint.
As is apparent from the graph, the angular velocity is larger in the swing phase than in the stance phase.
For example, the absolute value of the angular velocity is about 400 (Deg / Sec) in the swing phase, whereas the absolute value is about 200 (Deg / Sec) in the stance.

As described above, it can be seen that the joint moment is large and the angular velocity is small in the stance phase, and conversely, the joint moment is small and the angular velocity is large in the swing phase.
In the conventional example, there is a case where resistance by the knee joint assist actuator 18 is felt in the region 51 where the angular velocity of the swing leg period indicated by the wavy line is fast, but the wearable robot 1 is driven by the knee joint assist actuator 18 by the region 51. In order to cut off the transmission system that transmits the driving force to the system, the movement of the lower limb by the wearer is not interlocked with the knee joint assist actuator 18 (that is, the lower limb is free to move), and the wearer naturally moves the lower limb. Can exercise.

FIG. 5 is a flowchart for explaining a procedure in which the control device 2 operates the clutch 36.
The following processing is performed by the CPU of the control device 2 according to a predetermined program.
In the following, the right foot clutch 36 will be described, but the left foot clutch 36 is processed in the same manner.

First, the control device 2 acquires the state (connected or released) of the right foot clutch 36 (step 5).
This can be done by acquiring the operating state of the disc moving member 43.
Next, the control device 2 determines whether the clutch 36 is being connected or released from the state of the clutch 36 (step 10).

When the clutch 36 is engaged (step 10; Y), the control device 2 performs a release determination process as to whether or not the clutch 36 can be released (step 15).
As a result of the release determination process, when it is determined that the release is possible (step 20; Y), the control device 2 releases the clutch 36 (step 25).
On the other hand, if it is determined that the clutch cannot be released (step 20; N), the control device 2 maintains the connection of the clutch 36 (step 30).

When it is determined in step 10 that the clutch 36 is disengaged (step 10; N), the control device 2 performs a connection determination process as to whether or not the clutch 36 can be connected (step 35).
As a result of the connection determination process, when it is determined that the connection is established (step 40; Y), the control device 2 connects the clutch 36 (step 45).
On the other hand, if it is determined that the connection is not established (step 40; N), the control device 2 maintains the release of the clutch 36 (step 50).

FIG. 6 is a flowchart for explaining the procedure of the release determination process in step 15 of FIG.
First, the control device 2 acquires the ground contact state of the right foot (step 105). This can be acquired by an output from the toe reaction force sensor 10, the heel reaction force sensor 11, or the like.
Next, it is determined whether only the right toe is in contact with the ground (step 110). This is to detect the initial stage and the final stage since only the toes are grounded at the initial stage and the final stage when standing.
When other than the toes (here, the heel) is also grounded (step 110; N), the control device 2 determines that the right foot is in the stance phase and determines that the clutch 36 is maintained connected (step 140).

On the other hand, when only the toe is grounded (step 110; Y), the control device 2 acquires the angle and angular velocity of the right hip joint (step 115). This is calculated by the various parameter calculation unit 4.
Next, the control device 2 determines whether or not the right foot is moving backward and backward from the wearer's body from the angle and angular velocity of the hip joint (step 120).
When at least one of the above conditions is not satisfied (step 120; N), the control device 2 determines that it is in the initial stage of the stance phase and determines that the clutch 36 is maintained (step 140).

When both of the above conditions are satisfied (step 120; Y), the control device 2 determines that it is the end of the stance phase.
The control device 2 estimates the joint moment of the knee joint of the right foot (step 125). This estimated value is calculated by various parameter calculation units 4.
Next, the control device 2 determines whether or not the estimated joint moment is equal to or less than a predetermined threshold (step 130).

When the joint moment is equal to or smaller than the threshold (step 130; Y), the control device 2 determines that the clutch 36 is released (step 135), and when the joint moment is larger than the threshold (step 130; N), It is determined that the connection of the clutch 36 is maintained (step 140).
Thus, by providing the threshold value of the joint moment in the determination criterion, it is possible to prevent the clutch 36 from being released even though torque is required at the end of the stance phase.

FIG. 7 is a flowchart for explaining the procedure of the connection determination process in step 35 of FIG.
First, the control device 2 estimates the joint moment of the knee joint of the right foot (step 205). This estimation is performed by the various parameter calculation unit 4.
Next, the control device 2 determines whether or not the joint moment is equal to or greater than a predetermined threshold (step 210).

When the joint moment is equal to or greater than the threshold (step 210; Y), the control device 2 determines that the clutch 36 is engaged (step 235).
When the joint moment is less than the threshold value (step 210; N), the control device 2 acquires the ground contact state of the right foot (step 215). This is acquired from the outputs of the toe reaction force sensor 10 and the heel reaction force sensor 11.

Next, the control device 2 determines whether or not the right foot is in contact with the acquired contact state (step 220).
When it is determined that the right foot is not in contact with the ground (step 220; N), the control device 2 determines to maintain the clutch 36 open (step 240).
On the other hand, when it is determined that the right foot is in contact with the ground (step 220; Y), the control device 2 acquires the previous state from the data (step 225). This data is stored in the storage unit 7. This is to determine whether or not it is the moment when the foot is grounded by comparing with the immediately preceding data.

Next, the control device 2 determines whether or not the right foot was not grounded in the previous data (step 230).
If the right foot is in contact with the previous data (step 230; N), the control device 2 determines that it is the end of the stance phase and determines to maintain the clutch 36 open (step 240).
On the other hand, when the right foot is not grounded in the previous data (step 230; Y), the control device 2 determines that it is the moment when the right foot is grounded and determines that the clutch 36 is connected (step 235).

In the embodiment described above, the transmission system is connected and released by the clutch 36 for the knee joint, but this is not limited to the knee joint, and can be applied to the hip joint and ankle joint.
For example, when the wearer is running or walking fast, it may be desirable to disengage the clutch in the same way for the hip joint.

In the embodiment described above, the following effects can be obtained.
(1) By disengaging the clutch 36 during the swing phase, it is not necessary to move the drive system that is a power source that is a load, that is, the knee joint assist actuator 18, and it is possible to move with a light force.
(2) It is not necessary for the knee joint motor 31 to cope with both high-output low-speed rotation during standing and low-output high-speed rotation during the swing phase, and it is not necessary to use an expensive and highly functional knee joint motor. Can be reduced.
(3) When the clutch 36 is disengaged, it is not necessary to drive the knee joint motor 31 and energy consumption can be reduced.
(4) By preventing whether the knee joint moment is equal to or less than a threshold value at the end of the swing leg period, the clutch 36 is prevented from being released despite the need for torque by the knee joint assist actuator 18. Can do.
(5) The clutch 36 can be connected at the moment when the foot contacts the ground by referring to the previous data at the start of the swing phase.

According to the embodiment described above, the following configuration can be obtained.
The wearable robot 1 includes holding means for holding the legs of the walking support target person in order to hold the legs of the wearer by the upper thigh connecting member 26 and the lower thigh connecting member 27.
Further, since the knee joint assist actuator 18 outputs an assist force for assisting the joint moment generated at the knee joint, the wearable robot 1 assists in outputting an assist force for assisting the joint moment generated at the joint of the leg. Force output means is provided.
Further, since the clutch 36 transmits the assist force to the crus coupling member 27, the wearable robot 1 includes a transmission unit that transmits the output assist force to the holding unit.
Since the control device 2 releases the clutch 36 during the free leg period, the wearable robot 1 includes an opening unit that releases transmission by the transmission unit.
For example, the opening by the opening means is configured to be automatically opened when a predetermined condition is satisfied, for example, in the case of a swing leg period, or to be manually opened by the wearer as necessary. You can also.

  The joint that is connected / released by the clutch mechanism is particularly effective at the knee joint, so that the joint can be a knee joint.

  Since the wearable robot 1 releases the clutch 36 during the free leg period of the walking cycle, the releasing means releases the transmission in synchronization with the walking cycle, and also releases the transmission during the free leg period. doing.

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 9 Clutch control part 10 Toe reaction force sensor 11 踵 Reaction force sensor 11 12 toe posture sensor 13 heel 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 waist attachment portion 22 upper leg attachment portion 23 lower leg attachment portion 24 foot Mounting part 26 Upper thigh connecting member 27 Lower thigh connecting member 31 Knee joint motor 32 Rotating shaft 33 Bevel gear 34 Knee joint shaft 35 Bevel gear 36 Clutch 41 Bevel gear side disc 42 Knee joint axis side disc 43 Disc moving member 51 Region

Claims (5)

Holding means for holding the legs of the walking support target person;
An assist force output means for outputting an assist force for assisting a joint moment generated at the joint of the leg,
A transmission means for transmitting the output assist force to the holding means;
Opening means for releasing transmission by the transmission means;
A walking support device characterized by comprising:   The walking support device according to claim 1, wherein the joint is a knee joint.   The walking support device according to claim 1, wherein the opening unit releases the transmission in synchronization with a walking cycle.   The walking support device according to claim 1, wherein the opening unit releases the transmission during a swing leg period. An assist force output function for outputting an assist force for assisting a joint moment generated at a joint of a leg of a walking support target;
A transmission function for transmitting the output assist force to a holding means for holding a leg;
An opening function for releasing transmission by the transmission means;
A walking support program that uses a computer.

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