JP5168158B2 - Walking training system - Google Patents

Description

  The present invention relates to a walking training system that assists walking motion by applying torque to a user's leg. In particular, the present invention relates to a walking training system that can quickly stop the control of an actuator when a user loses balance. In this specification, a leg that a user can freely move is referred to as a healthy leg, and a leg that cannot be freely moved is referred to as an affected leg.

  A walking assist device that assists the user's walking by applying torque to the joint of the affected leg has been studied. For example, Patent Document 1 discloses a walking assist device that applies torque to a joint of an affected leg so as to be the same as the movement of a healthy leg. The device that assists the user's muscular strength and that is worn by the user is particularly important for the fail-safe function. For example, in Patent Document 2, it is determined that the user is in a dangerous posture state that the user is likely to fall. A technique for sometimes stopping control of an actuator is disclosed.

JP 2003-116893 A JP 2001-276100 A

  The technique of Patent Document 2 determines whether or not the user is likely to fall from the user's posture, but it is difficult to accurately determine from the posture. In addition, the walking assistance device that applies force (torque) directly to the user's body is not based on whether or not the user is likely to fall, but whether or not the user is in a state suitable for receiving assistance for the planned walking motion. Judgment should be made. The “state of the user not suitable for receiving walking assistance” is typically a state in which the user is out of balance. This invention was created in view of the said subject. An object of the present invention is to provide a walking training system that accurately detects a state in which a user has lost balance and quickly stops control according to walking motion.

  The user tries to catch something if he loses his balance. Auxiliary tools such as handrails are arranged in an environment for walking training instead of a place for living. When the user loses balance, the user often deposits his / her own weight on an auxiliary tool (for example, a handrail) disposed in the vicinity. In other words, when the user's load applied to the auxiliary tool is large, the user is likely to be out of balance. The present invention was created based on the above findings. The present invention focuses on the fact that an auxiliary tool can be provided in addition to the walking assistance device worn by the user in a walking training field. By using an auxiliary tool that cooperates with the walking assistance device worn by the user, it is accurately detected that the user has lost balance.

  The present invention can be embodied in a walking training system including a leg brace and an auxiliary tool. The leg brace has an actuator that applies torque to the joint of the user's leg and a controller that controls the actuator, and is attached to the user's leg. The controller controls the actuator according to the user's walking motion. An auxiliary tool is arrange | positioned in the vicinity of a user, and a user can deposit a body and can support own weight. The auxiliary tool may be, for example, a handrail, a cane, a hanging tool that is suspended from above and can be grasped by the user, or a suspension that supports the user from above.

  A load sensor is attached to the auxiliary tool. A load sensor detects the load which an auxiliary tool receives from a user. This walking training system is characterized in that the controller stops the control according to the walking motion when the load detected by the load sensor exceeds a threshold value. In this walking training system, a load sensor is provided in an auxiliary tool that allows a user to hold his / her body and support his / her own weight, and when the load detected by the load sensor is excessive, control of the actuator corresponding to the walking motion is stopped. This walking training system detects that the user has lost the balance with the force sensor of the auxiliary tool, and quickly stops the control according to the walking motion.

  For example, the user may put a hand on the handrail even if the user is not out of balance, for example, to obtain a sense of security. Therefore, when a load is applied to the auxiliary tool, it is not always likely that the user is out of balance. When the assisting tool is a wand, the user pokes the wand even during walking, so the wand receives a load. The controller of the walking training system stops the control corresponding to the walking motion when the load applied to the assisting device exceeds the threshold value.

  In other words, the walking training system uses an auxiliary tool as a so-called emergency stop switch. Note that the auxiliary tool is an emergency stop switch, and may also serve as a human-machine interface for the user to intentionally operate the walking training system. Specifically, when the user touches the auxiliary tool lightly, the controller may control the walking training system so that the user can stand still in an upright posture.

  Various levels can be considered even when the user is out of balance. Therefore, it is preferable that the controller of the walking assist system stops the control according to the walking motion and executes different stop control modes according to the feature amount determined from the user's posture. The feature amount determined from the user's posture includes, for example, the posture angle of the user's trunk with respect to the vertical direction, the contact state of the foot (difference of whether or not the contact is made), or the distance between both feet.

  The leg brace has, for example, a multi-link structure in which an upper link attached to a user's upper leg and a lower link attached to the lower leg are connected to be swingable by a joint. The joint is positioned coaxially with the knee when the leg brace is worn by the user. That is, such a brace assists walking by appropriately applying torque to the user's knee. The leg brace includes a prohibiting unit that prohibits rotation of the joint. The prohibition means may typically be a brake.

  The stop control mode when the leg brace has the above-described configuration is, for example, as follows. The leg brace includes a sensor that detects the posture of the user. The “user posture” is the inclination angle of the user's trunk with respect to the vertical direction, the degree of bending of the legs, the position of the foot, and the like. In this specification, the inclination angle with respect to the vertical direction may be referred to as an absolute inclination angle. The controller of the walking training system stops the control according to the walking motion, and the first stop control mode that activates the prohibiting means when the first feature amount determined from the user's posture is within a predetermined first range. When the first feature amount is outside the first range, the second stop control mode is executed in which the prohibiting means is released to allow the lower link to swing. The first feature amount may be, for example, the inclination angle of the user's trunk. A case where the user's inclination angle is within the first range corresponds to a case where the balance is slightly lost. In such a case, the prohibiting means is actuated to lock the joint so that the balance can be easily restored by the legs. On the other hand, a case where the user's inclination angle is outside the first range corresponds to a case where the balance is largely lost. In such a case, the prohibiting means is released to allow the joint to swing freely so as not to prevent free swinging of the user's lower limbs. As an example, the controller executes the first stop control mode in which the brake is activated when the posture angle of the user's trunk is within a threshold angle (within the first range) with respect to the vertical direction, and the posture of the trunk When the angle exceeds the threshold angle (outside the first range), the second stop control mode for releasing the brake is executed. The threshold angle is defined as 30 degrees, for example.

  It is preferable that the leg orthosis further includes a damper for imparting damping to the rotation of the lower link. At this time, the second stop control mode described above is further divided into two sub-modes (a third stop control mode and a fourth stop control mode). That is, when the first feature amount is outside the first range, the controller releases the prohibiting means and activates the damper when the second feature amount determined from the user's posture is within the second range. When the second feature amount is outside the second range, it is preferable to execute the fourth stop control mode in which the prohibiting unit is released and the damper is released. The second feature amount may be, for example, the distance between the user's feet. As described above, since the position of each foot is obtained from the posture of the leg (that is, the angle of each joint of the leg), the distance between both feet is also determined from the posture of the user. The lower limb of the user can be bent gently by operating the damper. On the other hand, when the damper is released, the user's lower limb can be quickly bent. As a specific example, the controller determines that the posture angle of the user's trunk exceeds the threshold angle with respect to the vertical direction (when outside the first range), and further the distance between the both feet (second feature amount). When the distance is greater than or equal to the threshold distance, that is, when the second feature value is within the second range, the third stop control mode for releasing the brake and operating the damper is executed. On the other hand, when the distance between both feet is less than the threshold distance, that is, when the second feature amount is outside the second range, the controller executes the fourth stop control mode in which the brake is released and the damper is also released.

  The walking training system of the present invention has a solid fail safe, detects that the user has lost balance, and quickly stops the control according to the walking motion.

It is a schematic diagram of the walking training system of the 1st example. It is a schematic diagram of a leg brace. The list of stop control modes which the controller of the 1st example performs is shown. It is a schematic diagram of the walking training system of 2nd Example. The list of the stop control mode which the controller of 2nd Example performs is shown. It is a schematic diagram of the walking training system of 3rd Example. It is a schematic diagram of the walking training system of 4th Example. It is a schematic diagram of the walking training system of 5th Example.

  (First Embodiment) A walking training system 100 according to a first embodiment will be described with reference to the drawings. The walking training system 100 assists the user's walking motion. FIG. 1 is a schematic diagram of a walking training system 100. The walking training system 100 includes a leg brace 12 worn by a user and a handrail 50. The handrail 50 is a kind of assisting tool that allows the user to deposit his body and support his / her own weight when the balance is lost. As will be described later, the handrail 50 also functions as a human-machine interface of the walking training system 100. For example, when the user touches the handrail 50 lightly, the walking training system 100 stops the leg brace 12 by controlling the leg brace 12 so that the user can maintain an upright posture. FIG. 1 shows only the outline of the leg brace 12. FIG. 2 shows the structure of the leg orthosis 12. 2A shows a front view, and FIG. 2B shows a side view. In this embodiment, the leg brace 12 can apply an appropriate torque to the user's left knee joint.

  First, the leg orthosis 12 will be described with reference to FIG. The leg brace 12 has a structure in which a right leg brace 12R and a left leg brace 12L are connected by a support link 30. The left leg orthosis 12L is attached to the outside of the leg along the thigh from the user. The left leg orthosis 12L is a multi-link mechanism having an upper link 14L, a lower link 16L, and a sole link 18L. Similarly to the left leg orthosis 12L, the right leg orthosis 12R is a multi-link mechanism having an upper link 14R, a lower link 16R, and a sole link 18R. The left and right leg appliances 12R and 12L are connected by a support link 30. The support link 30 is disposed on the back side of the user and connects the upper end of the right leg orthosis 12R and the upper end of the left leg orthosis 12L.

  The left leg orthosis 12L will be described in detail. The upper end of the upper link 14L is connected to the support link 30 via the waist joint 20aL. The lower link 16L is connected to the upper link 14L by a knee joint 20bL located outside the knee. The sole link 18L is swingably connected to the lower link 16L by an ankle joint 20cL located outside the user's heel. The upper link 14L is fixed to the user's thigh with a belt. The lower link 16L is fixed to the user's lower leg with a belt. The sole link 18L is fixed to the user's sole with a belt. The belt for fixing the sole link 18L is not shown. The support link 30 is fixed to the trunk (waist) of the user.

  When the user wears the left leg orthosis 12L, the waist joint 20aL, the knee joint 20bL, and the ankle joint 20cL are positioned coaxially with the pitch axis of the user's hip joint, the pitch axis of the knee joint, and the pitch axis of the ankle joint, respectively. To do. That is, the left knee orthosis 12L can swing according to the movement of the user's left leg. An encoder 21 for detecting the angle between the links is attached to each joint.

  A plurality of ground sensors 22a and 22b are attached to the bottom surface of the foot link 18L. As shown in FIG. 2B, the plurality of ground sensors are attached to the front link 18L at a distance from the front and the rear. The ground sensor 22a is attached to the front of the sole link 18L, and the ground sensor 22b is attached to the rear of the sole link 18L. The front ground sensor 22a is attached to a position corresponding to the user's thumb ball, and the rear ground sensor 22b is attached to a position corresponding to the user's thumb. Each grounding sensor detects the grounding between the sole link 18L and the walking surface.

  A motor 32 is attached to the knee joint 20bL. The motor 32 is located outside the user's knee joint. The motor 32 can rotate the lower link 16L with respect to the upper link 14L. That is, the motor 32 can apply torque to the user's left knee joint. The motor 32 includes a brake 33 and a damper 34. When the brake 33 is operated, the relative positions of the upper link 12L and the lower link 16L are fixed. That is, the knee joint 20bL is locked. The damper 34 provides attenuation to the rotation of the lower link 16L. The damper 34 is not always operated, but is operated according to a command from the controller 40.

  The right leg link 12R has the same structure as the left leg link 12L except for the motor 32 (brake 33, damper 34).

  A controller 40 is attached to the support link 30. A tilt sensor 27 is provided inside the controller 40. The tilt sensor 27 detects the tilt angle (absolute tilt angle) of the support link 30 with respect to the vertical direction. The absolute inclination angle of the support link 30 corresponds to the absolute inclination angle of the user trunk.

  The controller 40 controls the motor 32 based on the outputs of the tilt angle sensor 27, the encoder 21, and the ground sensor 22. Specifically, the controller 40 corrects the walking pattern stored in advance according to the user's stride, walking speed, and slope angle of the walking surface, and follows the walking pattern in which the user's left leg is corrected. Torque is applied to the user's knee joint. Since the walking pattern of the walking training system and its correction are disclosed in detail in a patent application already filed (Japanese Patent Application No. 2008-235463, filed on September 12, 2008), description thereof is omitted here. The walking training system 100 controls the motor 32 to apply torque to the knee joint according to the user's walking motion using the walking pattern.

  Returning to FIG. 1, the handrail 50 will be described. A sheet-like touch sensor 54 is attached to the surface of the handrail 50. A force sensor 52 is attached to the column of the handrail 50. Signals from the touch sensor 54 and the force sensor 52 are sent to the controller 40 included in the leg orthosis 12. Although not shown, the handrail 50 is provided with a wireless device that sends a signal from the touch sensor 54 and the like to the controller 40.

  Processing of the controller 40 based on signals from the touch sensor 54 and the force sensor 52 will be described. The leg brace 12 drives the motor 32 so that the user's knee joint follows the trajectory drawn by the knee joint angle during walking. The control at this time corresponds to control according to walking motion. Hereinafter, “control according to walking motion” may be referred to as “walking assist control” for easy understanding. When the user touches the handrail 50, the touch sensor 54 is activated and the force sensor 52 detects a load applied to the handrail 50. The controller 40 ignores the output of the force sensor 52 when the load detected by the force sensor 52 does not exceed the load threshold. Here, the load threshold is set to, for example, half of the user's own weight.

  The touch sensor functions as a human-machine interface of the walking training system 100. That is, the user touches the handrail 50 lightly when he wants to stand still. When the touch sensor 54 is activated during the walking assistance control, the controller 40 stops the walking assistance control. At this time, the controller 40 controls the motor 32 at an angle at which the upper link 14L and the lower link 16L are in a straight line. Such control allows the user to maintain an upright posture. When the load detected by the force sensor 52 is equal to or less than the load threshold value and the touch sensor 54 is activated, there is a high possibility that the user has not lost the balance. In such a case, the controller 40 After controlling the motor 32 to a knee angle that can maintain an upright posture, the brake 33 is operated to stop the walking assist control.

  On the other hand, the force sensor 52 functions as an emergency stop switch of the walking training system 100. When the load detected by the force sensor 52 exceeds the load threshold, the user is likely to be out of balance and lean on the handrail. The controller 40 detects the timing when the load detected by the force sensor 52 exceeds the load threshold as the timing when the user is out of balance. When this timing is detected, the controller 40 stops the walking assist control and executes different stop control modes depending on the posture of the user when the load threshold is exceeded. Here, the “user posture” considered by the controller 40 is the absolute inclination angle of the user trunk and the distance between both feet. The absolute inclination angle of the user trunk is one of the feature quantities representing “user posture”. Since the distance between both feet is determined by the posture of the user's leg, in this specification, the distance between both feet is also regarded as one of the feature amounts representing the “user's posture”. Specifically, the controller 40 executes different stop control modes according to the absolute inclination angle of the user trunk when the load threshold is exceeded and the distance between both feet. The controller 40 obtains the absolute inclination angle of the user trunk from the inclination sensor 27. Further, the controller 40 obtains the distance between both feet from the angular joint angle measured by the encoder 20. Since the conversion from each joint angle of the multi-link mechanism to the position of the tip (foot) is well known as the kinematics of the robot, the description is omitted. In the following, for the sake of simplicity, the absolute inclination angle may be simply referred to as an inclination angle.

  FIG. 3 shows a list of stop control modes according to the user's posture. The stop control mode shown in FIG. 3 will be described. “Free (no damper)” means control in which the controller 40 releases the brake 33 and stops (releases) the damper 34. In this case, the lower link 16L can swing freely. “Free (with damper)” means control in which the controller 40 releases the brake 33 and operates the damper 34. In this case, the lower link 16L can rotate when an external force is applied, and attenuation is imparted to the rotation. “Lock” means control by which the controller 40 operates the brake 33. In this case, the knee joint 20bL is locked and the swinging of the lower link 16L is prohibited. The controller 40 starts any stop control mode and stops the motor 32. The above-mentioned several “stop control modes” can be generally expressed as a control for operating or releasing (stopping) a brake and a damper applied to the joint without actively driving the joint of the leg brace. Hereinafter, the control mode corresponding to “lock” is referred to as “first stop control mode”, the control mode corresponding to “free (with damper)” is referred to as “third stop control mode”, and “free (without damper)”. ) ”May be referred to as a“ fourth stop control mode ”. In addition, since both the third stop control mode and the fourth stop control mode are controls for releasing the brake 33, these may be collectively referred to as “second stop control mode”.

  As shown in FIG. 3, when the inclination angle A of the user's trunk exceeds 30 degrees, the controller 40 stops the walking assist control and executes the fourth stop control mode. The case where the tilt angle A exceeds 30 degrees corresponds to the case where the user is greatly out of balance. In this case, since the possibility that the user can recover the posture is small, the brake 33 is released and the damper 34 is released so that the lower link 16L can swing. Such control prevents excessive torque from being applied to the user's left knee.

  When the inclination angle A is 30 degrees or less, it corresponds to a state where the user is slightly out of balance. In this case, the controller 40 selects a different stop control mode depending on the type of the grounding leg and the foot distance W. When both legs are grounded and the distance W between the feet is 30 cm or less, the controller 40 executes the third stop control mode. That is, the controller 40 releases the brake 33 and operates the damper 34. When both legs are in contact with each other and the inter-foot distance W exceeds 30 cm, the controller 40 executes the first stop control mode. That is, the controller 40 operates the brake 33. When the affected leg is in the free leg state and the inter-foot distance W is 30 cm or less, the controller 40 executes the fourth stop control mode. That is, the controller 40 releases the brake 33 and releases (stops) the damper 34. When the affected leg is in the free leg state and the inter-foot distance W exceeds 30 cm, the controller 40 executes the third stop control mode. That is, the controller 40 releases the brake 33 and operates the damper 34. When the healthy leg is in the free leg state and the inter-foot distance W is 30 cm or less, the controller 40 executes the first stop control mode. When the healthy leg is in the free leg state and the inter-foot distance W exceeds 30 cm, the controller 40 executes the third stop control mode.

  The above stop control mode selection rule has the following advantages. When the inclination angle A is large, it is very likely that the user has greatly lost the balance. In such a case, since it is difficult for the user to restore the balance by himself, the lower link is made swingable so that no load is applied to the user's knee joint. When the inclination angle A is small and only the affected leg is grounded (that is, when the healthy leg is a free leg), the stop control mode is selected according to the distance W between both legs. When the distance W between both feet is small, the brake 33 is operated. When only the affected leg is grounded and the distance W between both feet is small, the brake 33 is operated to prevent an impact from being applied to the arm to support its own weight with a handrail or the like.

  As described above, the controller 40 stops the walking assist control and executes different stop control modes according to the feature amount representing the user's posture. This gait training system detects that the user has lost the balance by the force sensor of the assisting tool, and appropriately stops the walking assist control according to the user's posture at that time.

  The controller 40 according to the embodiment executes different stop control modes according to the feature amount determined from the user's posture. More specifically, the controller 40 determines whether the brake 33 and the damper 34 operate according to the inclination angle determined from the user's posture, whether each foot is floating, and the distance between both feet. An appropriate stop control mode is selected from a plurality of stop control modes defined by the combination of release and executed.

  Various modes other than the handrail 50 of the first embodiment are conceivable as auxiliary tools that the walking training system should have. Hereinafter, the preferable form of an auxiliary tool is demonstrated. In the following embodiments, the leg braces may be the same as those in the first embodiment, and therefore only the assisting devices will be described. In addition, in 2nd Example, the other selection rule of stop control mode is also illustrated.

  (2nd Example) FIG. 4: is a schematic diagram of the walking training system 200 of 2nd Example. The walking training system 200 includes a cane 60 as an auxiliary tool that supports the user's own weight. In the cane 60, a switch 64 is disposed at a gripping portion that the user grips. A force sensor 62 is disposed on the support of the cane. The user can operate the walking training system via the switch 64. When the load detected by the force sensor 62 built in the cane 60 exceeds half of the user's own weight, the walking training system 200 stops the walking assist control and exceeds the load threshold. Different stop control modes are executed according to the absolute inclination angle of the user's trunk and the distance between both feet.

FIG. 5 shows a list of stop control modes executed by the walking assist system 200 of the second embodiment. The controller 40 of the walking assist system 200 executes the first stop control mode when the inclination angle A of the trunk of the user is 30 degrees or less. That is, the controller 40 operates the brake 33. On the other hand, when the inclination angle A of the user's trunk exceeds 30 degrees, the controller 40 executes the second stop control mode. That is, the controller 40 releases the brake 33.
In other words, “30 degrees or less” is the first range. The controller 40 executes the first stop control mode when the tilt angle A is within the first range, and the first range when the tilt angle A is outside the first range. (2) The stop control mode is executed.

  Similar to the first embodiment, the second stop control mode for releasing the brake 33 is divided into a third stop control mode for operating the damper and a fourth stop control mode for releasing the damper. The controller 40 executes the third stop control mode when the distance W between both feet is 30 cm or more, and executes the fourth stop control mode when the distance W is less than 30 cm. In other words, “30 cm or more” is the second range. The controller 40 executes the third stop control mode when the distance W between both feet is within the second range, and when the distance W between both feet is outside the second range. The fourth stop control mode is executed.

  (3rd Example) FIG. 6: is a schematic diagram of the walking training system 300 of 3rd Example. The walking training system 300 includes a crane 70 as an auxiliary tool that supports the user's own weight. The crane 70 includes a crane rail 76 and a hanging tool 74 that moves along the crane rail 76. The hanging tool 74 is a tool for supporting its own weight when the user loses balance. A force sensor 72 is disposed on the hanging tool 74. When the load detected by the force sensor 72 exceeds half of the user's own weight, the walking training device 300 stops the walking assist control according to the same rules as the walking training system of the first embodiment or the second embodiment. A stop control mode corresponding to the user's posture is executed.

  (4th Example) FIG. 7: is a schematic diagram of the walking training system 400 of 4th Example. The walking training system 400 includes a crane 80 as an auxiliary tool that supports the user's own weight. The crane 80 includes a crane rail 86 and a suspension 84 that moves along the crane rail 86. A harness 88 is attached to the lower end of the suspension 84. The user wears the leg brace 12 and the harness 88 on the back. When the user loses balance, the harness 88 and the suspension 84 support the user. Even when the user loses balance, the user is prevented from falling by the crane 80. A force sensor 82 is disposed on the suspension 84. When the load detected by the force sensor 82 exceeds half of the user's own weight, the walking training apparatus 400 stops the walking assist control according to the same rules as those of the walking training system of the first embodiment or the second embodiment, and the user. The stop control mode corresponding to the posture is executed.

  (5th Example) FIG. 8: is a schematic diagram of the walking training system 500 of 5th Example. This walking training system 500 includes a self-propelled crane 90. The self-propelled crane 90 moves with the user. A hanging tool 94 is attached to the tip of the self-propelled crane 90. The hanging tool 94 is a tool for supporting its own weight when the user loses balance. A force sensor 92 is disposed on the hanger 94. When the load detected by the force sensor 92 exceeds half of the user's own weight, the walking training apparatus 500 stops the walking assist control according to the same rules as the walking training system of the first embodiment or the second embodiment. A stop control mode corresponding to the user's posture is executed.

  A modification of the walking training system according to the embodiment will be described. The leg orthosis 12 of an Example is provided with the motor which applies a torque to a user's one knee. The leg brace may include an actuator that applies torque to leg joints other than the knee. The leg brace may be one that assists walking motion by applying torque to the joints of both legs of the user.

  The leg orthosis 12 may reduce the angular gain of the motor in the damper mode instead of including the damper 34. By reducing the angle gain, the same effect as that of the damper can be obtained.

  The walking training system may employ a strain gauge as a sensor for detecting a load applied to an auxiliary tool such as a handrail instead of the force sensor.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

12, 12R, 12L: Leg orthosis 14R, 14L: Upper link 16R, 16L: Lower link 18R, 18L: Sole link 20: Joint 21: Encoder 22: Ground sensor 27: Inclination sensor 30: Support link 32: Motor 33: Brake 34: Damper 40: Controller 50: Handrail (auxiliary tool)
52: Force sensor

Claims (6)

A leg brace having an actuator mounted on the user's leg and applying torque to the leg joint;
A controller that controls the actuator in accordance with the user's walking motion;
An auxiliary tool that allows the user to hold the body and support its own weight,
A load sensor that detects a load that the auxiliary tool receives from the user,
The walking training system characterized in that the controller stops the control according to the walking motion when the load detected by the load sensor exceeds a threshold value.   2. The walking training system according to claim 1, wherein the controller stops control according to a walking motion and executes different stop control modes according to a feature amount determined from a user's posture. The leg brace is
The upper link attached to the user's upper leg and the lower link attached to the lower leg have a multi-link structure in which the joint is swingably connected by a joint,
A sensor for detecting the posture of the user;
A prohibition means for prohibiting rotation of the joint;
With
The controller stops the control according to the walking motion and executes a first stop control mode in which the prohibiting unit is operated when the first feature amount determined from the user's posture is within a predetermined first range. 3. The walking according to claim 2, wherein when the first feature amount is outside the first range, a second stop control mode in which the prohibiting means is released and the lower link is allowed to swing is executed. Training system. The leg brace further comprises a damper that provides damping to the rotation of the lower link,
When the first feature value is outside the first range, the controller releases the prohibiting means and activates the damper when the second feature value determined from the user's posture is within the second range. 4. The walking training system according to claim 3, wherein when the second feature amount is outside the second range, a fourth stop control mode is executed in which the prohibiting unit is released and the damper is released.   The walking training system according to claim 4, wherein the first feature amount is an inclination angle of a user's trunk, and the second feature amount is a distance between both feet of the user.   The assisting tool is any one of a handrail, a cane, a hanging tool that is suspended from above and can be grasped by a user, and a suspension that supports the user from above. The walking training system according to any one of 5.

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