JP5892506B2 - Healthy side information feedback type walking assist device - Google Patents

Description

  The present invention relates to a healthy information feedback type walking assist device that drives an affected actuator and controls the position of each joint angle of a diseased lower limb synchronously based on hip / knee joint angle information of a healthy lower limb.

Cerebral vascular injury is a general term for diseases that affect the brain by causing ischemia or hemorrhage in the cranium due to pathological changes in blood vessels or hemodynamics that perfuse the brain. Particularly, a syndrome mainly composed of rapidly developing neurological signs of the brain is called a stroke, and is classified into cerebral infarction, cerebral hemorrhage, subarachnoid hemorrhage and the like. Then, cerebral infarction (cerebral infarction: a condition causing liquefaction necrosis of the brain parenchyma due to cerebral artery occlusion), cerebral hemorrhage (cerebral hemorrhage: bleeding caused by rupture of intracerebral artery), subarachnoid hemorrhage (subarachnoid hemorrhage) Bleeding in the subarachnoid space), transient cerebral ischemia, hypertensive encephalopathy.
In general, stroke is often accompanied by sensory disturbances such as motor paralysis of the upper and lower limbs, and neglect of the half-side space in which half of the visual field is unrecognizable, higher dysfunction (aphasia, apraxia, agnosia), mental May have damage. The process of recovery from stroke hemiplegia is time-lapse, and it is flaccid paralysis immediately after the onset, but it often shifts to spastic paralysis due to changes over time.

The brain functions differently depending on the part, and there is functional localization in the motor area that controls the movement. Subarachnoid hemorrhage tends to cause headaches and disturbances of consciousness. In addition, in cerebral infarction or cerebral hemorrhage, the portion and the degree of difficulty of movement vary depending on the damaged brain portion. Hemiplegia, as a rule, occurs in the upper and lower limbs opposite to the brain lesion. It is known that paralysis is more often seen in the upper limbs than in the lower limbs, and occurs more strongly in parts far from the center.
Motor paralysis is a condition in which there is a disorder in the path from the motor center to the muscle fiber, and voluntary movement is not possible. There are essentially different central palsy (upper motor neuropathy) and peripheral palsy (lower motor neuropathy).
Peripheral paralysis occurs when the pathway of the lower motor neuron from the anterior horn cells of the spinal cord to the neuromuscular junction is impaired. It is caused by polio, which is a lesion of anterior horn cells, and nerve roots, plexus, and peripheral neuropathy caused by inflammation, compression, trauma, and the like.
In central paralysis, there is no direct change in the lower motor neuron from the anterior horn cells of the spinal cord to the neuromuscular junction, and the complex from the upper motor control center centering on the cerebral cortex to the anterior horn cells. It happens somewhere in the motor integration system. Hemiplegia due to cerebrovascular disorder is central paralysis.

Immediately after the occurrence of hemiplegia due to a stroke, flaccid paralysis often occurs and later shifts to spastic paralysis. When the resistance of the external force applied when bending the joint is smaller than normal, it is called relaxation, and when it is larger, it is called spasticity. A tension knee means a state where the knee bends to the opposite side when standing. Further, the varus refers to a state where the sole is twisted inward, and the pointed foot refers to a state where the ankle is walking with only the fingertips stuck.
Paralysis due to stroke is characterized by a specific contraction pattern occurring when trying to move rather than weakening the force. Even if you try to move some muscles, you can see a unique movement pattern in the recovery process of paralysis due to the movement of various muscles at the same time, which is called joint exercise. Also, if you try too hard to move a part of your body, you often involuntarily postural reflexes in other parts, which is called associative movement.
In the swing phase during walking on the paralyzed side, drooping legs are seen at the ankle joint. The drooping foot is a state where dorsiflexion cannot be achieved as expected. In addition, the gait of walking while swinging the paralyzed lower limb into a semi-circle is seen. The healthy hip and knee joints may be operated in a compensatory manner, resulting in an asymmetrical walk.

Excessive rest causes secondary complications such as pressure ulcers (bed slippage), muscle atrophy, and decreased bone density. All of them interfere with activities of daily living (ADL). Many of the patients who develop the disease are elderly people, and the elderly people generally have poor physical strength, and their resilience and willingness to recover are inferior. For this reason, disuse syndrome develops due to being bedridden more than necessary, and falls into a vicious circle of becoming a long-term bedridden patient. Therefore, in order to prevent the disuse syndrome, it is necessary to do personal activities as actively as possible.
In spinal animals such as cats and dogs that perform quadrupedal walking, a stepping reflex is seen, and it is known that a central pattern generator (CPG) present in the brainstem, spinal cord, etc. is involved. CPG refers to a neural network that generates a periodic movement pattern without sensory information. Regarding human walking, it is suggested that CPG exists in the spinal cord network. In order to mobilize the CPG, it is necessary to have information on the hip joint flexion and extension and load from the sole. In addition, it is considered that spinal nerve circuit is activated by applying afferent stimulation from the contralateral leg and contributes to the development of locomotor output. Therefore, there is a possibility that a smoother nerve output can be induced by giving appropriate nerve information input from the non-paralyzed foot (hereinafter, healthy side) to the paralyzed foot (hereinafter, affected side) or from the affected side to the healthy side.

  In rehabilitation for patients with hemiplegia due to cerebrovascular disorder, training is performed so that daily activities can be performed independently. Daily life operations include meal operation, toilet operation, conditioning operation, changing operation, bathing operation, communication operation, and movement operation, and life-related operations include operations such as cooking, washing, and cleaning. Among them, the moving operation is meaningless in itself, but is an indispensable operation for performing other operations. In gait training, a series of movements in walking, such as swinging out the lower limbs, supporting the weight, and moving the center of gravity, are trained using walking sticks and walking braces. Support by is required. When hemiplegic patients walk, compensation is performed on the healthy side. Due to the plasticity of the nervous system, the nervous system forms a compensating action on the healthy side, and the affected side declines and induces muscle atrophy and bone density reduction.

According to Wernig et al. In a study focusing on walking training for hemiplegic patients, BWSTT (Body Weight) is a load-free walking training for 33 hemiplegic patients who can barely walk by using canes and walker. It has been reported that 25 people were able to re-acquire independent walking without using these walking aids by performing Support Treadmill Training).
As an exercise therapy for promoting the recovery of hemiplegia, there is a method called a facilitating technique for inducing exercise by moving the paralyzed foot with a physical therapist (PT). Among them, there is a treatment called “Neurological rehabilitation based up the BOBATH concept” for adult stroke hemiplegic patients. Repetition time and manpower are required, but if it is mild, the facilitating technique may have helped improve not only the left-right symmetry of walking but also the left-right symmetry of brain motor cortex activity There is.

From the above, it is considered effective to give walking information to move the foot symmetrically, flex and extend the hip joint, and give load information from the sole.
One of the therapies for hemiplegia caused by cerebrovascular disorder is brace therapy. This has been incorporated into exercise therapy from an early stage in order to improve walking and activities of daily living. Acquiring and improving walking ability is a major goal in rehabilitation of hemiplegia. In addition, exercise therapy while using a brace can lead to promotion of motor function and improvement of recovery.
The process of recovery from stroke hemiplegia shifts from flaccid paralysis to spastic paralysis, and the movement pattern is governed by joint movement, resulting in gait disturbance. For this reason, the lower limb orthosis plays a major role.
A so-called “master-slave type rehabilitation system” in which rehabilitation on the paralyzed side is performed using a normal function on the non-paralyzed side in a hemiplegic patient or the like has already been proposed (for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-164860

However, fluctuations are seen in the biological signal. Similar to the heartbeat, fluctuations (fluctuations) are also seen in the rhythm of successive walking cycles. This fluctuation is not regarded as a mere random noise (thermal fluctuation) but has been regarded as a chaos that can explain the behavior deterministically, and the rhythm generation mechanism of the spinal CPG has a fractal (self-similar hierarchical structure) property. It is known to be seen. According to Housedorf et al., 1 / f fluctuation is observed in the walking cycle (duplicate walking time) in walking of a healthy person for a long time. The 1 / f fluctuation is fluctuation in which the slope of the log-log graph of the result of spectrum analysis (power spectrum) falls to the right.
As an example of application of fluctuation, there is a report that a learning effect is obtained in a learning process with appropriate fluctuation. The effect of incorporating 1 / f fluctuation in rehabilitation is expected.
While hemiplegic patient walking training mimics the walking of a healthy person, it presents a unique walking form and is accompanied by compensation on the healthy side, which may lead to functional decline on the affected side. In addition, rehabilitation using a load-free walking training robot is also performed. However, if training with a certain input is performed, it becomes passive training, so it is important to bring out the trainee's positiveness. Furthermore, the joint angle change during walking, the timing of swinging out the left and right feet, and the walking speed differ depending on the individual.
As described above, it is desired to develop a healthy side information feedback type walking assist device capable of performing walking training with a gait close to that of a healthy person and a gait suitable for an individual.
In addition, since walking speed varies depending on the individual and it is considered that the walking cycle includes fluctuations, it is necessary to adjust the time delay according to the walking cycle.

Therefore, the present invention is intended for patients with hemiplegia due to stroke, acquires joint angle information of the healthy lower limb, gives time delay to the joint of the affected lower limb, and feeds back the angle information on the healthy side to obtain the joint angle of the affected lower limb. It is an object of the present invention to provide a healthy side information feedback walking aid that enables training with a gait close to that of a healthy person and a gait that suits an individual by controlling the position.
Specifically, when tracking the slave with a certain time delay relative to the master, if the time delay is too short with respect to the walking cycle, each joint of the slave during the single leg support period begins to bend, and the balance is lost. There is a risk that. Therefore, it aims at adjusting time delay according to a master's walk cycle. In walking, it is necessary to adjust the slave to an appropriate walking cycle and left and right time delays. Since it is considered that the operation of the master is not always constant and changes, the slave needs to be able to follow the command angle. By controlling the position of each joint angle of the slave in synchronization with the movement of the master's hip and knee joints, the slave's response when the master's movement period is changed is examined. The purpose is to transmit the operation cycle of the master.

The healthy side information feedback type walking assist device of the present invention according to claim 1 has a master mechanism as a healthy side and a slave mechanism as a diseased side, and the master mechanism is for a hip joint attached to a hip joint part. An angle detector and a knee joint angle detector attached to the knee joint, the slave mechanism comprising: a slave hip joint mechanism that drives the hip joint; and a slave knee joint mechanism that drives the knee joint The slave hip joint mechanism portion and the slave knee joint mechanism portion are healthy side information feedback type walking assist devices each having a drive source and a drive mechanism, and have threshold values for determining flexion motion and extension motion in advance. set, when the master knee joint angle detected by the knee joint for angle detector exceeds the threshold value, it is determined that the bending operation, extending the time Te "0 The instruction of the extension operation to the slave mechanism is stopped, and while the bending operation is determined, the maximum angle of the master knee joint angle is updated and the bending time Tf is calculated. When the master knee joint angle detected by the joint angle detector is equal to or less than the threshold, the time of one cycle commanded to the slave mechanism is calculated from the bending time Tf immediately before being obtained, By setting the bending time Tf to “0”, the instruction of the bending operation to the slave mechanism is stopped, and while the extension operation is determined, the minimum angle of the master knee joint angle is updated and the extension is performed. When the time Te is calculated and it is determined that the extension time Te is longer than the time of the one cycle, it is determined that the wearer has stopped walking and the crotch and knee command angles are set to “0”. By the above Stop instruction of the bending operation and the stretching motion of the over blanking mechanism, the bending time Tf, the maximum angle of the master knee joint angle, the slave knee from the minimum angle of the extension time Te, and the master knee joint angle A command angle to the joint mechanism is calculated and output in units of one step, and the slave is delayed by a predetermined phase from the time when the master knee joint angle detected by the knee joint angle detector falls below the threshold. Bending is started by operating the driving source of the mechanism.
According to a second aspect of the present invention, in the unaffected side information feedback type walking assist device according to the first aspect, an angular velocity for operating the slave knee joint mechanism unit from the bending time and the maximum angle of the master knee joint angle. And the slave mechanism is bent and extended by feedback control after the master knee joint angle falls below the threshold value.

According to the present invention, the time at which each joint of the slave leg can be bent can be brought closer to the time at which the master becomes the minimum bending angle, and the time delay can be adjusted in accordance with the master's walking cycle. .
In addition, according to the present invention, by synchronizing the slave joint angles with the movement of the master's hip and knee joints, even if the operation period on the master side changes, Can be transmitted.
For these reasons, according to the present invention, it is possible to incorporate 1 / f fluctuation in rehabilitation, and the effect of walking training is expected.

1 is an external view of a healthy information feedback type walking assist device according to an embodiment of the present invention. System configuration diagram of the device Front view of the long leg brace of the device Side view of the same length lower limb orthosis The figure which shows the state at the time of the maximum bending of the orthosis hip joint part and the maximum extension The figure which shows the state at the time of the maximum bending of the orthosis hip joint part and the maximum extension The figure which shows the state at the time of the maximum bending of the orthosis knee joint part and the maximum extension The figure which shows the state at the time of the maximum bending of the orthosis knee joint part and the maximum extension Side view showing a slave hip joint mechanism according to the present embodiment. 9 is an enlarged view of the main part of FIG. 9 at the maximum bending. Mechanism model diagram of the mechanism External view of motor unit of the same mechanism Side view of slave knee joint mechanism according to this embodiment 9 is an enlarged view of the main part of FIG. 9 at the maximum bending. Mechanism model diagram of the mechanism Diagram showing set value of power supply of linear servo controller Diagram showing the maximum current setting value of the linear servo controller A graph showing the change in joint angle when the slave is made to follow the hip master with a certain delay. Graph showing the joint angle change when the slave is made to follow the knee joint master with a certain time delay Figure showing experimental results The figure which shows the attachment method to each left joint of a long leg brace Graph showing an example of each joint angle change measured Graph showing the relationship between the left and right knee joint angles during walking The figure which shows the average value and standard deviation of the maximum bending angle of each joint Graph showing the average value and standard deviation of the maximum flexion angle of each joint Schematic diagram of how to generate slave command angle from master joint angle information by time delay adjustment method Flow chart of operation by time delay adjustment method Graph showing the follow-up motion at each joint Graph showing the follow-up motion at each joint Diagram showing master and slave operation cycle and time delay, and maximum bending angle of slave with respect to input Fig. 3 is an external view of a healthy side information feedback walking assistive device according to another embodiment of the present invention. The figure explaining the length calculation of the actuator in the angle variable θ Diagram showing the appearance of the experimental model System configuration diagram of experimental model I / O waveform diagram

The healthy side information feedback type walking assist device according to the first embodiment of the present invention sets a threshold value for judging a bending motion and an extension motion in advance , and the master knee joint angle detected by the knee joint angle detector is If the threshold value is exceeded, it is determined that the movement is a bending operation, and the extension time Te is set to “0” to stop the instruction of the extension operation to the slave mechanism. The maximum joint angle is updated and the flexion time Tf is calculated. When the master knee joint angle detected by the knee joint angle detector is equal to or smaller than the threshold value, the slave is determined from the previous flexion time Tf already obtained. By calculating the time of one cycle commanded to the mechanism and setting the bending time Tf to “0”, the instruction of the bending operation to the slave mechanism is stopped, and while the extension operation is determined, the master knee joint angle is changed. Update minimum angle At the same time, when the extension time Te is calculated and it is determined that the extension time Te is longer than one cycle time, it is determined that the wearer has stopped walking, and the command angle of the crotch and knee is set to “0”. Thus, the instruction of the bending operation and the extension operation to the slave mechanism is stopped, and the command to the slave knee joint mechanism unit from the bending time Tf, the maximum angle of the master knee joint angle, the extension time Te, and the minimum angle of the master knee joint angle. The angle is calculated and output in increments of one step, and the master knee joint angle detected by the knee joint angle detector falls below the threshold, and then the slave mechanism drive source is operated with a predetermined phase delay to bend. It is what is started. According to the present embodiment, the time at which each joint of the slave side leg starts to be bent can be brought close to the time at which the master becomes the minimum bending angle, and the time delay is adjusted according to the master's walking cycle. Can do.

In the second embodiment of the present invention, in the healthy side information feedback type walking assist device according to the first embodiment, an angular velocity for operating the slave mechanism is determined from the bending time and the maximum angle of the master knee joint angle. The slave mechanism is bent and extended by feedback control after the master knee joint angle falls below the threshold value. According to the present embodiment, by synchronizing the slave joint angle with the operation of the master knee joint, even if the master operation cycle changes, the master operation cycle Can be transmitted.

Hereinafter, a healthy information feedback type walking assist device according to an embodiment of the present invention will be described.
FIG. 1 is an external view of a healthy side information feedback walking aid according to this embodiment, and FIG. 2 is a system configuration diagram of the apparatus.
The master mechanism 10 with the right foot as the healthy side, and the slave mechanism 20 with the left foot as the affected side. The master mechanism 10 acquires angle information from a hip joint angle detector (potentiometer) 11A attached to the hip joint and a knee joint angle detector (potentiometer) 11B attached to the knee joint. The slave mechanism 20 includes a slave hip joint mechanism 20A that drives the hip joint and a slave knee joint mechanism 20B that drives the knee joint. The slave hip joint mechanism portion 20A includes a drive source (DC motor) 21A and a drive mechanism (ball screw and L-shaped link) 22A, and the slave knee joint mechanism portion 20B includes a drive source (DC motor) 21B and a drive mechanism (ball screw). L-type link) 22B. A linear servo controller 31, encoders 32A and 32B, a pulse counter board 33, and an AD / DA board 34 are connected to the slave mechanism 20.

  Analog joint angle information from the hip joint angle detector 11A and knee joint angle detector 11B attached to the master mechanism 10 is AD-converted by the AD / DA board 34 and taken into the control unit (PC) 35 for control. A time delay is given by the unit 35, the information DA-converted by the AD / DA board 34 is sent to the linear servo controller 31, and the slave joint angle information is fed back by the encoders 32A and 32B integrated with the drive sources 21A and 21B. And angle control.

The healthy side information feedback type walking assist device according to the present embodiment is based on a general long leg brace. FIG. 3 is a front view of this type of long leg brace, and FIG. 4 is a side view of the same leg brace. The long leg brace used in this example is made of duralumin, has an outer diameter of 1200 × 420 × 150 mm, and a weight of 3 kg.
The movable range of each joint part of the long leg brace has a structure that does not obstruct the movable range of the joint of the wearer. In the orthosis hip joint, the bending direction is 140 ° and the extension direction is 20 °, and in the orthosis knee joint, the bending direction is 150 ° and the extension direction is 0 °. However, the movable range of each joint when worn by a person varies depending on the physique of the individual.

The state at the time of the maximum bending of the orthosis hip joint part and the maximum extension is shown in FIGS. The state at the time of the maximum bending | flexion of the orthosis knee joint part and the maximum extension is shown in FIG.7 and FIG.8.
As the hip joint angle detector 11A and knee joint angle detector 11B, contact-type potentiometers (manufactured by Green Sokki Co., Ltd.) were used.

9 is a side view of the slave hip joint mechanism according to the present embodiment, FIG. 10 is an enlarged view of the main part of FIG. 9 at the time of maximum bending, and FIG. 11 is a mechanism model diagram of the mechanism.
In FIG. 11, the hip joint bending angle is θ _h , and the position of the ball screw C of the hip joint B is X _h . Moving the X _h by rotating the ball screw C in the motor unit, to control the hip flexion angle theta _h. However, since there is play due to the point A sliding up and down about 10 mm and play due to the point A ′ rotating around the point A, the hip flexion angle when external force is applied even if the position of the ball screw C is fixed θ _h changes about 30 ° at the maximum. As for the slave angle, since the hip flexion angle is obtained by linear conversion from the encoder pulse signal for the rotation angle of the motor, the error fluctuates due to the active action of the wearer and the influence of the own weight. However, this play can reduce the burden on the wearer.

  FIG. 12 shows a hip joint motor unit. As shown in the figure, the hip motor unit uses a combination of a motor, a gear head, and encoders 32A and 32B. In this embodiment, a motor (manufactured by maxon, RE25, φ25 mm, graphite brush, 18 W) in which a gear head with a reduction ratio of 14 and a rotary encoder are assembled is used. The encoders 32A and 32B have a resolution of 512 pulses / rev. The encoder MR Type ML manufactured by maxon.

FIG. 13 is a side view showing a slave knee joint mechanism according to the present embodiment, FIG. 14 is an enlarged view of a main part of FIG. 9 at the time of maximum bending, and FIG. 15 is a mechanism model diagram of the mechanism.
In FIG. 15, it is assumed that the knee joint bending angle is θ _k1 and the position of the ball screw D of the knee joint E is X _k . Since there is a play in which the links F and G rotate in the knee joint mechanism, even if the position of the ball screw D is fixed, the knee joint bending angle θ _k1 changes by a maximum of about 30 ° when an external force is applied. This play is thought to reduce the burden on the wearer, but the controllable angle is 65 °.
As the motor unit of the knee joint mechanism unit, a motor (manufactured by maxon, RE26, φ26 mm, graphite brush, 18 W) combined with a gear head having a reduction ratio of 3 and 8 and a rotary encoder is used.

In the present embodiment, the voltage value is acquired by using potentiometers 11A and 11B this time to acquire the angle information on the healthy side. An AD / DA board (PCI-3523A, manufactured by Interface Co., Ltd.) was used for acquiring voltage values of the potentiometers 11A and 11B and outputting D / A to the actuator unit.
A pulse counter board (Interface, Inc., PCI-6204) was used to obtain the operating angle by the encoder arranged on the output shaft of the DC motor.
Single-ended input uses 2 channels and performs 1-fold phase difference pulse count.
A 4-quadrant linear servo controller (manufactured by maxon, 4-Q-DC Servo Control LSC 30/2) for processing a command signal sent from the D / A board from the PC 35 and controlling a motor for driving the hip and knee joints. ) Was used for each motor. This driver has five systems of control: an lxR correction (rotational speed control) control mode, a variable voltage control mode, a digital encoder rotational speed control mode, a DC tacho rotational speed control control mode, and a current control mode. Then, the current control mode was used.

Hereinafter, a constant time delayed operation confirmation experiment in the healthy side information feedback type walking assist device according to the present embodiment will be described.
In order to evaluate the time delay, amplitude ratio, and operation cycle ratio, which are considered to be important when performing the actual walking assistance operation, an operation confirmation experiment of the operation of causing the master to follow the slave with a certain time delay was performed.
The experimental devices include a healthy side information feedback type walking assist device (long leg device), potentiometer (joint angle evaluation POT) (manufactured by Tokyo Cosmos Electric Co., Ltd.), breadboard (manufactured by Sanhayato, SRH-53), and stabilized direct current. A power source 1 (manufactured by Kikusui Electronics Co., Ltd., PMC18-3), a stabilized DC power source 2 (manufactured by Takasago Seisakusho, LXO18-2B), and a stabilized DC power source 3 (manufactured by Kikusui Electronics Industrial Co., Ltd., PMC35-2) were used.

FIG. 16 shows the set value of the stabilized DC power supply used, and FIG. 17 shows the set value of the linear servo controller. The maximum current setting value of the stabilized DC power supply for the linear servo amplifier was determined from the maximum continuous current of the motor. Further, the proportional control equation for calculating the control input was determined as V _set = K _p (θ _m −θ _s ). V _set is a control input to the linear servo amplifier (saturated at ± 10 V), K _p is a proportional gain (0, 5 for the hip joint, 2, 0 for the knee joint), θ _m is the joint angle of the master, and θ _s is It is the joint angle of the slave.
The experiment was performed according to the following procedure.
First, each joint on the master side is bent and extended 20 times with a period of about 4 seconds so as to be close to a walking motion. Next, feedback control of each joint on the slave side was performed with a fixed time delay based on the angle information of each joint on the master side subjected to the 30-point moving average filter. Finally, each joint angle was measured at a sampling frequency of 20 Hz.

Experimental results and discussion are shown below.
FIG. 18 shows hip joints, and FIG. 19 shows changes in joint angles when the slaves follow the masters of the knee joints with a certain time delay. The time delay was defined as the time from the maximum bending of the master to the maximum bending of the slave. In order to evaluate the tracking error, the difference between the maximum bending angle and the minimum bending angle was calculated as the amplitude for each of the hip and knee joints of the master angle and the slave angle. In addition, in order to evaluate the fluctuation of the cycle between the master and the slave, the interval of maximum bending for each joint was obtained as the operation cycle. As the angle information of the slave, since the difference between the angle information from the potentiometer and the encoder was within 10 ° at the maximum, the angle information from the potentiometer was used because it was considered that there was no difference regardless of which angle information was used. .

  FIG. 20 shows the experimental results. In the knee joint, the average amplitude of the slave is 0.6 and the variation is large compared to the master. This is because if the hip joint is not bent about 20 ° at the start of flexion of the knee joint, the operation could be slowed due to mechanical problems, and the master operation range was given an input larger than the controllable range of the slave. This is thought to be due to the failure. However, since the ratio of the master to the slave is 1.0 with respect to the period, it can be considered that reproduction is possible with the slave. Although the number of flexing motions was different, the cycle ratio was slightly improved at the knee joint.

Below, the basic experiment result of the lower limb joint angle change measurement at the time of wearing the orthosis in the healthy side information feedback type walking assist device according to the present embodiment will be described.
Since a fixed time delay cannot cope with a change in the walking cycle, it is necessary to adjust the slave operation time delay in accordance with the master's walking cycle. At that time, the parameters for calculating the operation command from the master signal are set as follows, the walking cycle when generating the input to each slave joint device, the maximum bending angle of each joint, the slave operation for the master side In order to determine the time delay, the joint angle during walking is measured.
As the experimental device, a long leg brace and a potentiometer (manufactured by Tokyo Cosmos Electric Co., Ltd.) were used. For the long leg brace, the slave (left side) mechanism was removed.

FIG. 21 shows a method of attaching the long leg brace to the left joints. As shown in the figure, potentiometers were attached to the hip joints and knee joints of both legs of the long leg prosthesis with a pelvic belt, which is the foundation of the healthy side information feedback type walking assistive device.
The test subjects were 5 healthy men in their 20s. The subject was wearing a long leg brace, and the change in joint angle was measured at 20 Hz when the straight distance was reciprocated. The walking distance was limited to 3 m, and in order to make a difference in walking speed, walking was measured when the number of steps was specified as about 10 on the forward path, and free walking was measured on the return path.

Experimental results and discussion are shown below.
FIG. 22 shows an example of each joint angle change measured.
Looking at hip joint angle changes, flexion and extension were repeated alternately, and there was a tendency for flexion to be abrupt compared to extension. When the relationship between the left and right hip joint angle changes is viewed globally, it can be said that the phase is almost opposite. For this reason, it is conceivable to perform a reciprocal motion to extend the opposite side when one side is bent with respect to the hip joint. However, depending on the subject, there is a difference in motion speed between flexion and extension, so if the position control is performed at a command angle obtained by inverting the joint angle change on the opposite side, it may differ from the actual motion.
Looking at the knee joint angle change, the double knee action is not so much seen, and the flexion time is shorter than that of the hip joint. This is considered to be due to the fact that the resistance caused by attaching the long leg brace and the angle being measured are the rotation axes of the long leg brace and do not coincide with the rotation axes of the joints of the human body. Looking at the relationship between the change in the angle of the left and right knee joints, after the knee joint performs a large flexion / extension movement, a large flexion / extension movement of each joint of the contralateral leg starts. Is seen. This is considered to indicate that the other leg is swinging out while one leg is in the stance phase and maintaining the extended state. If this relationship breaks down and the operation is performed at a fast timing, the balance may be lost. A graph showing the relationship between the left and right knee joint angles at the same time is shown in FIG.

Also, looking at the interlocking movements of the hip and knee joints, the flexion of each joint starts almost simultaneously to swing out the foot. The time required for the knee joint flexion / extension motion is roughly half the time required for the hip joint flexion / extension motion.
The point where a large flexion / extension motion can be seen alternately at the left and right in the knee joint, and the time required to perform one large flexion / extension at a time is that the hip joint motion is about twice the knee joint motion, and the time to start flexion Paying attention to the fact that the hip joint and the knee joint are almost simultaneous, we considered that the slave's motion is started after the master's knee joint performs the stretching motion. It is considered that the time delay can be changed according to the walking cycle.

At this time, a method of generating a command angle to the slave side based on the time taken for one walking cycle from the master and the maximum bending angle of each joint will be considered.
As a method of acquiring the maximum bending angle and its cycle in each cycle, there are a method of paying attention to the angular velocity and a method of paying attention to the angle.
In the method of paying attention to the angular velocity, it is determined that the bending operation is performed when the angular velocity is positive continuously and the extension operation is performed when the angular velocity is negative continuously. However, since this method includes differentiation of angle information, setting of conditions is not easy due to the influence of noise. The method of paying attention to the angle is to judge that the angle is bent when the angle is larger than a certain value, and the extension is less than that. It is thought that it is hard to be affected by noise.
Therefore, a method of paying attention to the angle was adopted. Specifically, the time required for the bending / extending operation of each slave joint is determined from the time during which the knee joint is bent (bending time). Further, the maximum angle is acquired during bending, and the maximum angle is updated each time the extension is performed.

  In order to determine a threshold value for discriminating between flexion and extension, the maximum angle of each joint will be described. 24 and 25 show the average value and standard deviation of the maximum bending angle of each joint. When the left and right were compared, no significant difference was found, so it seems that there is no problem in using the maximum angle on one side for the opposite side operation. Considering the magnitude of the double knee action, it overlaps with the maximum flexion angle of the knee joint, so that it is not sufficient for detecting the walking motion. Set as °. 22 and 23, this value is not appropriate depending on the individual, so it is considered that adjustment is actually required.

Below, the time delay adjustment method in the healthy side information feedback type walking assistance apparatus by a present Example is demonstrated.
If the slave is operated during the master's swing phase, the walking balance may be lost. Therefore, it is considered that the master joint angle information is used to determine whether or not the stance is made and the slave is operated after the stance. Therefore, a method other than causing the slave to follow the angle change of each master joint with a fixed time delay is considered. If the time delay is too short with respect to the walking cycle and the joints of the slaves during the single leg support period are started to bend, the balance may be lost. Consider mastering the master signal as a parameter and assisting walking by swinging out the slave's foot after the master knee joint has extended.

FIG. 26 shows a schematic diagram of a method for generating a slave command angle from master joint angle information by a time delay adjustment method. In actual control, parameters are updated sequentially, but individual differences and offsets in joint angle changes have structural backlash and are ignored because it is considered that there is a limit in control accuracy.
In FIG. 26, for the knee joint, the threshold value for judging flexion and extension is 30 °, and when it exceeds 30 ° of the threshold value, it becomes the flexion time, and when it falls below 30 °, it becomes the extension time. For the knee joint shown in FIG. 26, the flexion time of the master knee joint is between about 0.2 seconds and about 0.8 seconds, and the master knee joint angle falls below the threshold value of 30 ° from about 0.8 seconds. The extension time of the master knee joint is between 1.8 seconds when the master knee joint angle exceeds the threshold of 30 °.
The slave operation is started by detecting the end of the flexion time of the master knee joint (around 0.8 seconds), but since it is delayed by a preset phase (π / 4), the slave operation start is performed at the master knee joint. Delayed from the end of the bending time.
In FIG. 26, the first slave operation (approximately 0.8 seconds to 1.9 seconds) is detected by the end of the flexion time of the master knee joint (approximately 0.8 seconds). Near the second to about 0.8 seconds), the maximum angle of the master knee joint, the minimum angle of the master knee joint, the maximum angle of the master hip joint, and the minimum angle of the master hip joint. The next slave movement (from about 2.4 seconds to) is detected by the flexion time T (from about 1.8 seconds to about 2.4 seconds) and the end of the flexion time of the master knee joint (around 2.4 seconds). The data is determined based on the updated data of the maximum angle of the master knee joint, the minimum angle of the master knee joint, the maximum angle of the master hip joint, and the minimum angle of the master hip joint.
As described above, by delaying the phase by π / 4 from the time when the knee joint angle is less than 30 °, the time when the bending of each joint of the slave side leg is brought closer to the time when it becomes the minimum bending angle of the master. ing.

FIG. 27 shows a flowchart of the time delay adjustment method.
When master angle information is acquired, it is first determined whether or not the master knee joint is bent. If the master knee joint angle exceeds the threshold value, it is determined that the movement is a bending action (Yes), and the extension time Te is set to “0” to stop the extension operation instruction to the slave. While the bending motion is determined, the maximum angle of the master knee joint is updated and the bending time Tf is calculated.
When the master knee joint angle does not exceed the threshold value, it is determined that the bending operation is not performed (No), and it is determined whether or not the bending time Tf is “0”. When the bending time Tf is “0” (No), it is determined that the first step after the apparatus is mounted (from 0 to 0.2 seconds in FIG. 26), and the bending time Tf is “ If it is not “0” (Yes), the period of the slave command is calculated from the previous bending time already obtained. One period is determined based on the bending time Tf. For example, in the pre-verification in which the threshold value is 30 °, it is preferable that one cycle is four times Tf. However, it is necessary to set one cycle time by setting the threshold value. For example, the slave command cycle is calculated as 3 times Tf.
When the bending time Tf is not “0” (Yes), the slave command cycle is calculated, and the bending time Tf is set to “0” to stop the bending operation instruction to the slave. While the extension operation is determined, the minimum angle of the master knee joint is updated and the extension time Te is calculated.
If it is determined that the extension time is longer than one cycle time (Yes), it is determined that the wearer has stopped walking, and the command angle of the crotch and knee is set to “0” to bend to the slave. Stop the extension operation instruction.
If it is determined that the extension time is not longer than the time of one cycle (No), it is determined whether or not the master hip joint is bent. If the master hip joint angle exceeds the threshold value, it is determined as a bending motion (Yes), and the maximum angle of the master hip joint is updated while the bending motion is determined. If the master hip joint angle is below the threshold value, it is determined that the motion is not a bending motion (No), and the master hip joint minimum angle is updated while it is determined that the motion is an extension motion.
The command angles to the slave knee joint and slave hip joint are calculated and output from the flexion time, knee joint maximum angle, knee joint minimum angle, hip joint maximum angle, and hip joint minimum angle obtained as described above. Here, the command angles to the slave knee joint and the slave hip joint are calculated and output in units of one step.
When a certain threshold value is exceeded, it is determined that the body is flexed, and the master knee joint flexion time T seconds and the maximum movement angle A _h ° (difference between the maximum hip joint angle and the minimum hip joint angle), A _k ° (the maximum knee joint) Difference between the angle and the minimum knee joint angle). Based on the acquired information, the angular velocity ωrad / s for operating the slave is determined by Equation 1, and the commands θ _h ° and θ _k ° to each slave joint are calculated by Equations 2 and 3, respectively, and master knee joint extension is performed. Later, each joint of the slave is bent and extended by feedback control. However, the time t seconds is 0 seconds immediately after extension. In the present embodiment, the bending time T is calculated from the knee joint angle information of the master, and a value obtained by multiplying the bending time T by 4 is determined as the cycle. The slave hip joint does not measure the flexion time and determines the cycle, but interlocks with the movement of the slave knee joint.

... (Formula 1)

... (Formula 2)

... (Formula 3)

The flexion time is set when the master knee joint once exceeds the threshold (near 0.2 seconds) and falls below the threshold (near 0.8 seconds), and the angular velocity is determined by (Equation 1) based on this flexion time.
On the other hand, assuming that the angle at time 0 is the maximum and minimum, and continuously measuring the angles of the master knee joint and master hip joint, the respective maximum and minimum angles are updated, and the latest updated data is used. The slave operation is determined by (Expression 2) and (Expression 3).
Below, the experimental result of the operation confirmation of the time delay adjustment method in the healthy side information feedback type walking assist device according to the present embodiment will be described.
In order to confirm the feasibility of the time delay adjustment method described above, the response of the slave when the master is manually bent / extended is evaluated.
The experiment was performed with a phase delay of 45 ° also applied to the slave hip joint. First, the device is suspended on a pipe hanger with an S-shaped hook, and the pelvic belt portion is fixed vertically. Next, each joint on the master side is bent and extended five times, and the slave side is operated by applying the time delay adjustment method already described.

Experimental results and discussion are shown below.
28 and 29 show graphs of the follow-up operation at each joint. From FIG. 29, it can be confirmed that the bending operation on the slave side has started after the knee joint of the master falls below the threshold value of 30 °. It can be confirmed that there is no change in the slave joint command angle after 34 seconds when the flexion of the master knee joint angle does not exceed the threshold value of about 27 °.

FIG. 30 shows the operation cycle and time delay of the master and the slave, and the maximum bending angle of the slave with respect to the input. However, an average value and a standard deviation are shown for five operations in which the master knee joint exceeds the threshold value of 30 °. As for the knee joint, the ratio of the master knee joint flexion time to the time delay is about one time, although there is variation, it is considered that a rough operation can be realized. The time delay was obtained as the difference between the bending start time of the master angle and the slave angle by the encoder.
Since the maximum bending angle ratio of the slave to the input is almost 1 at the hip joint, a high follow-up result was obtained because it was a slow input. The knee joint is inferior because it is about 0.9 compared to the hip joint, but is considered to be able to follow the input. This is considered to be influenced by 10 ° of play given to the knee joint.

The present invention focuses on gait training for hemiplegic patients and enables gait training with a gait close to that of a healthy person and a gait suitable for an individual. As a result of the development of a healthy side information feedback type walking assistive device that drives the lower limb joint, the slave's knee joint mechanism was modified to limit play, and the response speed sufficient for walking of hemiplegic patients from step response experiments It was suggested to have
It was also confirmed that changes in the operation cycle on the master side can be reproduced on the slave side by making the slave follow the movement of the hip and knee joints of the master.
In addition, based on the information of flexion time and maximum angle acquired during flexion, we developed a technique to flex and extend each slave joint after extension of the master knee joint. By this method, it was confirmed that it is possible to adjust the time delay corresponding to the walking cycle on the healthy side.

From the above, it was possible to confirm the realization of the healthy information feedback type walking assistive device capable of adjusting the time delay.
In the future, it will be necessary to develop an operation command generation method that is close to past joint angle changes on the healthy side, and to conduct an evaluation experiment by a healthy person on a method for adjusting the time delay of slave operation. Specifically, it is necessary to investigate by focusing on such points as whether time delay does not prevent walking, and whether the change in walking cycle is different from normal walking.
Furthermore, in order to prevent disuse syndrome and improve QOL, it may be possible to expand to a device that supports improvement of health and physical fitness. Specifically, it is conceivable to construct a system that allows the movement of the lower limb joints during running from walking to about 6.0 km / s using a treadmill, excluding weight. In that case, it is necessary to modify the knee joint to a mechanism in which the knee of the support leg bends from the moment of contact to the vertical position, and to incorporate an unloading device for preventing the fall and supporting the body into the system. Conceivable. In addition, the orthosis is worn on the chair, but it is considered that a hip joint of 120 ° and a knee joint of about 100 ° are necessary as the movable range of each joint required for standing.

Next, a healthy information feedback type walking assist device according to another embodiment of the present invention will be described.
FIG. 31 is an external view of a healthy side information feedback walking aid according to another embodiment of the present invention.
In this embodiment, a healthy side information feedback type walking assist device using pneumatic driving is used. As shown in the figure, a long lower limb orthosis with a trunk was basically used, and four McKibben actuators were used for power.
In addition, it is the same as that of the said Example except the point made into the mechanism which used the McKibben type actuator for motive power. That is, also in the present embodiment, it is a master-slave type healthy-side feedback type walking assist device in which the healthy side is the master and the affected side is the slave.

Since this embodiment is a master-slave type, it is necessary to determine the phase difference in swinging left and right legs according to the walking speed because it requires voluntary movement, so real-time performance is not important, and a certain time delay element is used. A feedback control system is desirable. Therefore, the function of performing feedback control with a certain time delay on the healthy joint angle information brought about by spontaneous movement is provided. It is possible to actively mobilize the human nervous control system by inducing spontaneous exercise and training. At the present stage, it operates by an open circuit using a PC.
The McKibben actuator is well known as a pneumatic actuator that performs a contraction motion, and is also called a pneumatic artificial muscle. This actuator is lightweight, has a high output density, and a high output. In addition, there is no risk of ignition, electric shock, or contamination when a leak occurs. In addition, it is excellent in environmental resistance, such as being usable in water. It is also flexible and has characteristics similar to human muscle characteristics. Furthermore, the material cost is low.
In the present invention, an actuator manufactured by Kanda Communication Industrial Co. is used.

Here, calculation of the supply pressure to the actuator will be described.
FIG. 32 is a diagram for explaining the calculation of the actuator length in the angle variable θ. This system achieves position control using the joint angle on the affected side as an output variable. The contraction rate of the actuator changes depending on the supply pressure. The actuator length L shown in the figure is regarded as a function of the supply pressure, and L is determined by the following equation (Equation 4) according to the geometrical arrangement of the joint angle and the link.

... (Formula 4)

  a, b, c, and d are link lengths, and L is an actuator length. Using this, the same angle as the input angle is reproduced by inputting a voltage value that makes an arbitrary angle.

Next, an experimental model will be described.
FIG. 33 shows the appearance of the experimental model.
The present invention is intended for hemiplegic patients, and this time, an input angle is given from the input device instead of the healthy hip joint angle, and the affected hip joint angle is used as an experimental model. The experimental model is one degree of freedom simulating a hip joint based on the orthosis used in previous studies. The specifications are φ30 mm, L = 430 mm for the actuator, 10 kΩ for the potentiometer, and aluminum for the member.
The experimental model has actuators on both sides and wires are attached. The range of motion of the experimental model is ± 45 ° as a result of being derived using Equation 4.
In the experimental model, the center of rotation is the center of the axis of rotation (joint axis), and bending / extending motion is performed. The operating angle is acquired by a potentiometer attached to the rotating shaft.

FIG. 34 shows a system configuration diagram of the experimental model.
Since the experimental model is built-in control, the PC 35 is not used.
The information obtained from the healthy side potentiometer is in the flow of operating the actuator by adjusting the compressed air with the regulator through the built-in system and supplying the air to the actuator arranged in the experimental model.
The input / output operating angle is obtained from each potentiometer.

Next, the control program will be described.
Since this system feeds back angle information on the healthy side as a command value on the affected side, a time difference (phase difference) between the left and right legs peculiar to walking motion is required. Therefore, an algorithm is constructed so as to cause a time delay of 1.0 second with respect to the angle input from the healthy side. In addition, a time delay of 1.0 second is produced by the PIC microcomputer. A time delay of 1.0 second is equivalent to a walking motion of 2, 0 km / h per hour if a healthy person walks. It can be said that the speed of 2,0 km / h is sufficient for walking training.
In order to operate the joint angle of the experimental model, two actuators and two servo valves are required. These correspond to the main and antagonist muscles that are similar to human muscle characteristics.
The present invention reproduces the action of initiative / antagonism by threshold control. FIG. 35 shows input / output waveforms.
The threshold value is set to 2.5V with respect to the input voltage, and the output voltage is divided into two values of the input voltage of 2.5V or more and the following. At this time, the voltage waveform of 2.5V or less is inverted and output. By dividing into two, a main action and an antagonistic action are created.
In addition, although the present Example demonstrated as an apparatus with respect to a hemiplegic patient, this apparatus can also be used as an assist method with respect to the worker who has a light load on the healthy side and a heavy load on the affected side.

  Although this invention can be used with respect to a hemiplegic patient, it can also be used for the assist apparatus with respect to the operator who adds a big burden to one leg.

10 Master mechanism 20 Slave mechanism 11A Hip joint angle detector (potentiometer)
11B Knee joint angle detector (potentiometer)
20A Slave hip joint mechanism 20B Slave knee joint mechanism 21A Drive source (DC motor)
21B Drive source (DC motor)
22A Drive mechanism (ball screw and L-shaped link)
22B Drive mechanism (ball screw and L-shaped link)
31 Linear servo controller 32A, 32B Encoder 33 Pulse counter board 34 AD / DA board

Claims (2)

It has a master mechanism as the healthy side and a slave mechanism as the affected side,
The master mechanism includes a hip joint angle detector attached to the hip joint and a knee joint angle detector attached to the knee joint.
The slave mechanism is composed of a slave hip joint mechanism part that drives the hip joint part, and a slave knee joint mechanism part that drives the knee joint part,
The slave hip joint mechanism unit and the slave knee joint mechanism unit are healthy side information feedback type walking assist devices each having a drive source and a drive mechanism,
The threshold for determining the the bending operation and stretching motion preset,
When the master knee joint angle detected by the knee joint angle detector exceeds the threshold value, it is determined as the bending operation, and the extension time Te is set to “0” to thereby provide the slave mechanism with the While the instruction of the extension operation is stopped and the bending operation is determined, the maximum angle of the master knee joint angle is updated and the bending time Tf is calculated.
When the master knee joint angle detected by the knee joint angle detector is equal to or smaller than the threshold value, the time of one cycle commanded to the slave mechanism is calculated from the bending time Tf immediately before being obtained. When the bending time Tf is set to “0”, the instruction of the bending operation to the slave mechanism is stopped, and while the extension operation is determined, the minimum angle of the master knee joint angle is updated. Calculating the extension time Te;
If it is determined that the extension time Te is longer than the time of the one cycle, it is determined that the wearer has stopped walking and the crotch and knee command angles are set to “0” to the slave mechanism. Stop the instruction of the bending motion and the stretching motion of
Calculate and output the command angle to the slave knee joint mechanism unit from the bending time Tf, the maximum angle of the master knee joint angle, the extension time Te, and the minimum angle of the master knee joint angle in units of one step;
From the time when the master knee joint angle detected by the knee joint angle detector falls below the threshold, the drive mechanism of the slave mechanism is operated to start bending after being delayed by a predetermined phase. Healthy side information feedback type walking assist device. An angular velocity for operating the slave knee joint mechanism unit is determined from the flexion time and the maximum angle of the master knee joint angle, and the slave mechanism is bent and fed back by feedback control after the master knee joint angle falls below the threshold value. The unaffected side information feedback type walking assist device according to claim 1, wherein the walking side assist device is extended.