JP6872847B2 - Operation assist device, operation method of operation assist device, and operation assist control program - Google Patents

Description

The present invention belongs to the technical fields of the operation assisting device, the operation method of the operation assisting device, and the operation assisting control program. More specifically, it belongs to the technical field of the motion assisting device and the operating method of the motion assisting device used for recovery training of a patient with so-called knee joint extension failure, and the motion assisting control program used in the motion assisting device.

In recovery training, etc. (so-called rehabilitation, hereinafter simply referred to as "rehabilitation") performed by a patient with knee disease, the patient has conventionally performed the necessary rehabilitation by himself / herself with the assistance of, for example, a physiotherapist. It was. On the other hand, in recent years, rehabilitation by passive operation using a drive source such as a motor (rehabilitation performed by using an external force) has also begun to be performed. For rehabilitation by such passive movement, a so-called wearable assist robot that is attached to the patient's body and assists the movement of the knee joint is used. This assist robot is attached to the thigh and lower leg including the knee joint of the patient by using a harness or the like, and operates so as to assist (in other words, forcibly move) the movement of the knee joint. That is, for example, in the case of walking training, the assist robot operates so as to realize the movement as a knee joint in an appropriate walking pattern, and moves the knee joint. As a result, the patient can perform necessary rehabilitation by walking independently so as to follow the movement of the assist robot. As an assist robot that can be used for such rehabilitation, for example, there is a walking training device described in Patent Document 1 below.

On the other hand, in recent years, in such a state, as one of the treatment methods for the above-mentioned knee disease, total knee arthroplasty may be performed to replace a part or all of the sick knee joint with an artificial knee joint. .. However, it has also been found that so-called knee arthroplasty symptoms may occur in patients after total knee arthroplasty. Here, knee arthroplasty is a complete extension of the knee joint (straightening the lower leg when viewed from the thigh) during passive movements in which the knee joint is moved with the assistance of a person (assistant) or a device after total knee arthroplasty. It is possible to cut), but it is a state in which the above-mentioned full extension cannot be reached during self-movement (automatic movement). If such knee joint extension failure is left as it is, it may lead to an accident such as an unexpected fall during walking training, and therefore effective treatment is desired. However, for knee joint extension failure, a clear cause and a treatment method corresponding to the cause have not been found at present, and effective rehabilitation after the operation is desired.

Japanese Unexamined Patent Publication No. 2009-183657

Here, in the conventional rehabilitation for knee joint extension failure as described above, a physiotherapist or the like has been involved to directly assist the knee joint extension movement. Therefore, it is desired to utilize a device or the like capable of such rehabilitation without the full involvement of a physiotherapist or the like and having the above-mentioned drive source.

There is an assist robot for rehabilitation of patients after total knee arthroplasty, but the premise is that it is basically limited to patients who can flex and extend the knee joint and can walk to some extent. Therefore, there is no assist robot considered for the above-mentioned patients with knee joint insufficiency. Further, neither disclosure nor suggestion is found in Patent Document 1 regarding the rehabilitation of patients with knee joint extension insufficiency.

Therefore, the present invention has been made in view of the above requirements and various problems, and one example of the problem is to efficiently assist in rehabilitation for recovery of a patient with knee joint extension failure as described above. It is an object of the present invention to provide an operation assisting device that can be performed, an operation method of the operation assisting device, and an operation assisting control program used in the operation assisting device.

In order to solve the above problems, the invention according to claim 1 is a motion assisting device for assisting the knee joint movement of a person to be assisted in a sitting position, wherein the assisting means for assisting the knee joint extension motion and the above-mentioned A knee joint angle detecting means for detecting the flexion angle of the knee joint, and a first drive control means for assisting the extension operation by the auxiliary means after the detected flexion angle reaches a preset first threshold angle. The second threshold angle that is uniquely set in advance and is the second threshold angle that advances in the extension direction of the knee joint when viewed from the first threshold angle is the flexion angle detected while assisting the extension movement. In the case of, the second drive control means assisted by the auxiliary means so that the extension state in which the bending angle is the second threshold angle is maintained, and the detected bending angle is the second threshold angle. After the extended state is maintained, the third drive control means for stopping the assistance by the auxiliary means and opening the knee joint is provided.

In order to solve the above problems, the invention according to claim 6 is a motion assisting device for assisting the movement of the knee joint of a person to be assisted in a sitting position, and is an assisting means for assisting the extension motion of the knee joint. , The knee joint angle in the operation method of the motion assist device executed in the motion assist device including the knee joint angle detecting means, the first drive control means, the second drive control means, and the third drive control means. The detection means is a knee joint angle detecting step of detecting the flexion angle of the knee joint, and the first drive control means and the auxiliary means have the detected flexion angle as a preset first threshold angle. Hereinafter, the first drive control step for assisting the extension motion and the flexion angle detected by the second drive control means while assisting the extension motion are the extensions of the knee joint when viewed from the first threshold angle. When the second threshold angle advances in the direction and becomes the second threshold angle uniquely set in advance, the auxiliary means assists the bending angle to maintain the extended state which is the second threshold angle. After the second drive control step and the third drive control means maintain the extended state in which the detected flexion angle is the second threshold angle, the assist by the auxiliary means is stopped and the knee joint is stopped. A third drive control step is included.

In order to solve the above problems, the invention according to claim 7, wherein the first drive control means for the operation assisting device according to any one of claims 1 to 5 and the second drive control means Further, the computer provided as the third drive control means is made to function as the first drive control means, the second drive control means , and the third drive control means, respectively.

According to the invention according to any one of claims 1, 6 or 7 , the extension motion after the flexion angle of the knee joint reaches the first threshold angle is assisted, and the flexion angle is further increased. When the second threshold angle advanced in the extension direction reaches the second threshold angle uniquely set in advance, the extension state of the second threshold angle is assisted to be maintained. Therefore, assistance in rehabilitation for recovery of a patient with knee joint extension failure can be efficiently performed.
Further, after the extension state in which the flexion angle of the knee joint is the second threshold angle is maintained, the assistance by the assisting means is stopped and the knee joint is opened, so that the recovery of the extension failure by itself can be promoted. .. In the present invention, "opening" of the knee joint means that the assist to the knee joint by the driving means of the motion assist device according to the present invention is stopped, and the knee joint by the assisted person (for example, the patient in the following embodiment) is stopped. It means to make the state that does not interfere with the automatic operation of.

In order to solve the above problems, the invention according to claim 2 is the operation assisting device according to claim 1, wherein the detected bending angle of the second drive control means is the second threshold angle . It is configured to assist the assistive means to maintain the extended state of the knee joint for a preset threshold time.

According to the invention of claim 2, in addition to the action of the invention of claim 1, the extended state of the knee joint in which the flexion angle of the knee joint is the second threshold angle is maintained for a predetermined threshold time. It is possible to more effectively recover from the insufficiency of extension.

In order to solve the above problems, the invention according to claim 3 uniquely sets the second threshold angle as an angle corresponding to the horizontal in the operation assisting device according to claim 1 or 2. It is configured to be an angle.

According to the invention of claim 3, in addition to the action of the invention of claim 1 or 2, the second threshold angle is an angle uniquely set in advance as an angle corresponding to the horizontal. , It is possible to recover from extension failure more effectively.

In order to solve the above problems, the invention according to claim 4 is the operation assisting device according to any one of claims 1 to 3 , wherein the first threshold angle, the second threshold angle, or the like. A change operation means for accepting an operation for changing all or a part of the threshold time is further provided.

According to the invention of claim 4 , in addition to the action of the invention of any one of claims 1 to 3 , all or part of the first threshold angle, the second threshold angle or the threshold time. Since the operation for changing the above is accepted, it is possible to more effectively recover from the extension failure by setting the first threshold angle or the like arbitrarily by the person being assisted or the supervisor.

In order to solve the above problems, the invention according to claim 5 stops the assistance during the assistance by the auxiliary means in the operation assist device according to any one of claims 1 to 4. The knee joint is further provided with a stopping means for opening the knee joint.

According to the invention of claim 5 , in addition to the action of the invention of any one of claims 1 to 4 , it is optional to stop it and open the knee joint during assistance. Since it is possible, the knee joint can be protected even in an emergency.

According to the present invention, after starting the extension motion of the knee joint by itself, the extension motion after the flexion angle of the knee joint reaches the first threshold angle is assisted, and the flexion angle further advances in the extension direction. When the threshold angle is the second threshold angle that is uniquely set in advance, the extension state of the second threshold angle is assisted to be maintained.

Therefore, assistance in rehabilitation for recovery of a patient with knee joint extension failure can be efficiently performed.
Further, after the extension state in which the flexion angle of the knee joint is the second threshold angle is maintained, the assistance by the assisting means is stopped and the knee joint is opened, so that the recovery of the extension failure by itself can be promoted. ..

It is a state diagram when the assist device which concerns on embodiment is attached to a patient. It is a block diagram which shows the structure of the assist device which concerns on embodiment. It is a side view conceptual diagram which illustrates the state of a patient at the time of the assist operation by the assist device which concerns on embodiment, (a) is a side view conceptual diagram which illustrates the initial posture state, and (b) is the state at the time of assist start. Is a side view conceptual diagram illustrating the above, (c) is a side view conceptual diagram illustrating a state during assist, (d) is a side view conceptual diagram while maintaining an extended state, and (e) is an assist end. It is a side view conceptual diagram which exemplifies the later state, and (f) is a side view conceptual diagram which exemplifies the time when it returns to the initial posture state. It is a flowchart which shows the auxiliary operation by the assist device which concerns on embodiment. It is a timing chart which illustrates the state of each signal and the like at the time of auxiliary operation in the assist device which concerns on embodiment. It is a figure which illustrates the effect of the auxiliary operation in the assist device which concerns on embodiment.

Next, a mode for carrying out the present invention will be described with reference to FIGS. 1 to 6. The embodiment described below is an embodiment in which the present invention is applied to an assist device that assists the rehabilitation of the patient with knee joint extension failure. At this time, the patient corresponds to an example of the "assistant" according to the present invention.

Further, FIG. 1 is a state diagram when the assist device according to the embodiment is attached to a patient, FIG. 2 is a block diagram showing a configuration of the assist device, and FIG. 3 is a patient during an auxiliary operation in the assist device. It is a side view conceptual diagram which illustrates the state of. Further, FIG. 4 is a flowchart showing an example of auxiliary operation in the assist device, FIG. 5 is a timing chart illustrating a state of each signal or the like during the auxiliary operation in the assist device, and FIG. 6 is an auxiliary operation in the assist device. It is a figure which illustrates the effect of operation.

As shown in FIG. 1, the assist device S according to the embodiment is a lower limb portion of one of the patients to be assisted by the assist device S (that is, a lower limb including a knee joint in which the knee joint is incompletely extended). A drive unit 10 is provided, which is attached to each of the parts) by a detachable tape-shaped fixture or a fixture 6 such as a band. Then, as shown in FIG. 1, the drive unit 10 is attached to the joint portion of the patient's knee portion 5 and attached to the link mechanism portion 3 for flexing and extending the knee joint and the joint portion of the patient's hip joint 9. A link mechanism portion 8 for flexing and extending the hip joint is attached. When rehabilitation of knee joint insufficiency is performed using the assist device S according to the embodiment, basically, the patient is in a sitting position sitting on the chair C with the sole of the foot not touching the floor (see FIG. 1). ), The link mechanism unit 8 is not necessary for the rehabilitation (and the auxiliary operation for that purpose) according to the embodiment.

Of these, as shown in FIG. 1, the link mechanism portion 3 includes, for example, a first link 3a attached to the side surface of an upper leg pad 4 wrapped around the patient's thigh and a lower portion wrapped around the patient's lower leg. Includes a second link 3b attached to the side surface of the leg rest 7 and a third link 3c that receives power from the drive unit 10 and swings the second link 3b in the front-rear direction of walking with respect to the first link 3a. Consists of. The first link 3a is attached so as to extend from the lumbar side of the patient to the knee 5 side, and the second link 3b is attached so as to extend from the knee 5 side of the patient to the tip (ground) side of the leg. The first link 3a and the second link 3b are rotatably connected in the vicinity of the patient's knee 5.

The connecting portion has a built-in knee joint angle sensor that outputs knee joint angle data indicating the angle formed by the first link 3a and the second link 3b. This knee joint angle sensor is realized by, for example, a so-called potentiometer or the like. Further, the end portion of the third link 3c is connected to the vicinity of the center of the second link 3b. The upper leg pad 4 and the lower leg pad 7 each include a pair of leg rest members (not shown), and the leg rest members are arranged so as to cover the circumference of the thigh and lower leg of the patient. , It is detachably attached by the fixture 6. Further, the upper leg pad 4 and the lower leg pad 7 are formed by molding, for example, polypropylene resin or the like, and a stretchable sponge member or the like (not shown) is attached to a portion in contact with the thigh of the user. ..

Here, the assist device S according to the embodiment performs an assisting operation for rehabilitation of knee joint extension failure while the patient is sitting on the chair C as described above. Then, in the rehabilitation, the knee joint is repeatedly flexed and extended while sitting. At this time, when the knee joint is flexed, for example, the center of rotation of the fibula in the lower leg continuously moves posteriorly (in the back of the knee) and downward in the femur in response to the flexion, so-called rollback. It is known to occur. Therefore, in the connecting portion, the same rotation as the rollback is performed by using a non-circular gear having a bow-shaped virtual rotation center motion generating groove cam and a rollback motion generating groove cam corresponding to the movement shape of the rotation center. It realizes flexion and extension of the knee joint including movement of the center. It has been confirmed by the inventors of the present application and the like that the structure of such a connecting portion enables smooth flexing, especially when the knee joint is bent at 90 °.

On the other hand, as shown in FIG. 1, the link mechanism portion 8 is attached to the first link 8a attached to the side surface of the upper leg rest 4 and the side portion of the belt 23 wrapped around the waist of the patient. The two links 8b and the like are included. The first link 8a is attached so as to extend from the buttocks side of the patient to the knee 5 side, and the second link 8b is attached so as to extend from the lumbar side of the patient to the buttocks side. The first link 8a and the second link 8b are rotatably connected in the vicinity of the patient's crotch portion 9. This connecting portion also has a built-in hip joint angle sensor that outputs hip joint angle data indicating the angle formed by the first link 8a and the second link 8b. This hip joint angle sensor is also realized by, for example, a so-called potentiometer. As described above, the link mechanism unit 8 is not required for the rehabilitation according to the embodiment.

Next, in the drive unit 10, a control board for controlling the auxiliary operation by the assist device S according to the embodiment, and a DC (Direct Current) motor described later for driving the first link 3a to the third link 3c are installed. Batteries for the purpose are stored. At this time, the control board is equipped with a CPU or the like described later that controls the auxiliary operation by the assist device S according to the embodiment. In the following description, the auxiliary operation by the assist device according to the embodiment is simply referred to as "assist operation according to the embodiment".

Next, the configuration of the assist device S according to the embodiment will be described more specifically with reference to FIG.

As shown in FIG. 2, the assist device S according to the embodiment is provided with a CPU (Central Processing Unit) 42 provided on the control board and a position that can be operated by a patient, a physiotherapist, or the like, and gives a command to the CPU 42. It includes an operation unit 41 provided with operation buttons and the like for performing operations, and a display unit 40 composed of a liquid crystal display or the like connected to the CPU 42 and provided at a position where a patient, a physiotherapist, or the like can see. These are incorporated in the drive unit 10 as described above. The CPU 42 has a storage unit (not shown) that stores a control program that controls the operating system and the assist device S, detected data, and the like. This storage unit is composed of a ROM (Read Only Memory), a RAM (Random Access Memory), a hard disk, a silicon disk, or the like.

The drive system of the assist device S as a whole includes the drive unit 10, the fixture 6, the upper leg pad 4, the lower leg pad 7, the link mechanism portion 3 including the knee joint angle sensor 16, and the hip joint angle (not shown). A link mechanism unit 8 including a sensor and a link mechanism unit 8 are included. Further, the drive unit 10 includes a DC motor 50, a gear portion 52 connected to each link, and a clutch portion 51 that transmits a driving force from the DC motor 50 to each link via the gear portion 52. It has been.

In the above configuration, the rotation direction and rotation speed of the DC motor 50 and the release / connection control of the clutch unit 51 are controlled by the CPU 42, respectively. Further, the knee joint angle sensor 16 generates the knee joint angle data and outputs it to the CPU 42.

At this time, the DC motor 50 corresponds to an example of the "auxiliary means" according to the present invention, the knee joint angle sensor 16 corresponds to an example of the "knee joint angle detecting means" according to the present invention, and the CPU 42 corresponds to the present invention. An example of the "first drive control means" according to the present invention, an example of the "second drive control means" according to the present invention, an example of the "third drive control means" according to the present invention, and the "stop means" according to the present invention. Each corresponds to an example. Further, the operation unit 41 and the CPU 42 correspond to an example of the "change operation means" according to the present invention.

Next, the assist operation according to the embodiment will be described with reference to FIGS. 3 to 6.

First, an outline of the assist operation according to the embodiment will be described. In the assist operation, in order to effectively rehabilitate the knee joint insufficiency, first, as shown in FIG. 3A, a patient P wearing the assist device S (that is, a patient P in knee joint insufficiency) is subjected to. The assist operation is started from the initial posture state in which the lower leg can be freely moved while sitting on the chair C and the sole of the foot does not touch the floor. Note that, in FIG. 3, the illustration of the assist device S itself according to the embodiment is omitted for the sake of simplification of the description. After that, as shown in FIG. 3B, the patient P started to extend the knee joint by himself / herself, and the angle α between the central axis of the lower leg and the horizontal became a preset first threshold angle. Assistance by the assist device S is started from the timing, and as shown in FIG. 3C, the knee joint is extended by itself and the knee joint by the assistance to a preset target angle (for example, horizontal or preset extension corresponding to horizontal). Extend to the target angle). This extension target angle corresponds to an example of the "second threshold angle" according to the present invention. Then, when the knee joint is extended until the lower leg reaches the extension target angle, the state of the extension target angle is maintained for a threshold time as shown in FIG. 3 (d), and then as shown in FIG. 3 (e). The assistance by the assist device S is finished and the knee joint is opened. After that, the patient P returns to the original initial posture state by himself / herself as shown in FIG. 3 (f). By the above series of assist movements, the initial posture state → extension of the knee joint by one's own power → extension to the extension target angle with the assistance of the assist device S → the state of the extension target angle by one's own power and the assistance of the assist device S The assist operation according to one embodiment of maintenance → termination of assistance by the assist device S and opening of the knee joint → return to the initial posture state by oneself is completed.

Next, the threshold angle data and the threshold time data according to the embodiment, which are stored in advance in the storage unit to be used for the assist operation, will be described.

As the threshold angle data according to the embodiment, first, the CPU 42 recognizes that the patient P wearing the assist device S according to the embodiment is in the initial posture state by using the knee joint angle data. The initial posture threshold angle data is non-volatilely stored in the storage unit. Here, in the initial posture state, as shown in FIG. 3A, the assist device S is mounted in the state shown in FIG. 1 by preventing the driving force from the DC motor 50 from being transmitted to the link mechanism unit 3. The patient P sits on the chair C and has his lower leg open. That is, in the initial posture state, the patient P can freely move the knee joint by himself / herself. Then, when the patient P does not apply force to the lower leg in the state shown in FIG. 3A, the angle α is usually an angle close to a right angle. Therefore, the initial posture angle threshold value as the angle of the angle α is set to 90 °, and the initial posture threshold value angle data indicating this is stored in advance in the storage unit. Then, the CPU 42 recognizes that the patient P himself is in the initial posture state by detecting that the angle α is 90 ° or an angle in the vicinity thereof based on the knee joint angle data from the knee joint angle sensor 16. .. The initial posture threshold angle data is operated by the operation unit 41 while displaying the value on the display unit 40, for example, according to the progress of the rehabilitation, for example, the patient P or a physiotherapist who assists the rehabilitation ( Hereinafter, it can be arbitrarily changed by simply referring to "patient P, etc.").

Next, as the above threshold angle data, secondly, from the initial posture state shown in FIG. 3A, after the patient P starts to extend the knee joint by himself / herself, the angle α (which should start the assist operation according to the embodiment) The first threshold angle data, which is the knee joint angle data for the CPU 42 to recognize whether or not the angle is (see FIG. 3B), is non-volatilely stored in the storage unit. The first threshold angle data can also be arbitrarily changed by the patient P or the like like the initial posture threshold angle data, but as a specific value, for example, 10 ° to 30 ° is preferable.

Next, as the threshold angle data, thirdly, after the start of the assist operation according to the embodiment, the knee reaches the extension target angle (specifically, the angle corresponding to the horizontal) shown in FIGS. 3 (c) and 3 (d). The extension target angle data (in other words, the threshold angle data indicating whether or not the angle α has reached the extension target angle), which is the knee joint angle data for the CPU 42 to recognize whether or not the joint is extended, is stored. It is stored in the part non-volatile. When the extension target angle is horizontal, the extension target angle data is 0 °. Further, the threshold value data as the extension target angle data can be arbitrarily changed by the patient P or the like like the initial posture threshold angle data or the like, but as a specific value, 0 ° is preferable as described above. ..

Finally, as the threshold time data, the CPU 42 recognizes whether or not the threshold time for maintaining the extended state has elapsed after the knee joint of the patient P is in the extended state shown in FIG. 3 (d). The threshold time data of is non-volatilely stored in the storage unit. This threshold time data can also be arbitrarily changed by the patient P or the like like the initial posture threshold angle data or the like, but as a specific value, for example, about 0 seconds (that is, no extension maintenance) to 0.5 seconds is preferable. Is.

Next, the assist operation according to the embodiment, which is executed mainly by the CPU 42, will be specifically described.

In the assist operation, the CPU 42 stops other modes (for example, a walking assist mode using the link mechanism unit 8) that have been executed up to that point as the initialization process of the assist device S, and also implements the embodiment. The drive unit 10 is switched to the mode in which the assist operation is performed (step S1). After that, when the patient wearing the assist device S in the manner illustrated in FIG. 1 is seated on the chair C in order to receive assistance from the assist device S, the CPU 42 shifts the drive unit 10 to the stopped state (step S2). .. Next, the CPU 42 activates the drive unit 10 (step S3), and further shifts the drive unit 10 to the initial posture state shown in FIG. 3A (step S4).

At this time, in the initial posture state, the CPU 42 controls the driving force from the DC motor 50 so as not to be transmitted to the link mechanism unit 3, so that the automatic operation of the knee joint including the lower leg by the patient P is not hindered. .. As a result, since the patient P sits on the chair C without the legs attached, the lower leg of the patient P can be freely moved in an open state. Since the initial posture angle threshold data is 90 °, the CPU 42 detects that the angle α is 90 ° based on the knee joint angle data from the knee joint angle sensor 16, so that the patient P is initially set. Recognize that you are in a posture state.

After that, the CPU 42 starts the extension of the knee joint by the patient P by himself as shown in FIG. 3 (b), so that the angle α is the angle indicated by the first threshold angle data as shown in FIG. 3 (c). (In other words, whether or not it is time to start the assist operation according to the embodiment) is monitored (step S5). In the monitoring of step S5, if it is not yet the timing to start the assist operation according to the embodiment (step S5; NO), the CPU 42 waits with the lower leg open until the timing is reached. On the other hand, when the timing to start the assist operation according to the embodiment comes in the monitoring of step S5 (step S5; YES), the CPU 42 drives the DC motor 50 via the drive unit 10 and gradually performs the assist operation according to the embodiment. (Step S6), and further assists the knee joint to extend at a constant velocity (in other words, a constant angular velocity) (step S7).

In steps S6 and S7, for example, when the DC motor 50 is of the PWM (Pulse width Modulation) method, the CPU 42 gradually increases the PWM value at the stage of step S6, and sets the PWM value to, for example, 100% in step S7. The DC motor 50 is controlled so as to do so. As a more specific PWM value, according to a survey by the inventor of the present application, the torque of extension of the knee joint from the sitting position is 5.1 Nm to 11.5 Nm in elderly men and women over 60 years old. Therefore, it is preferable to set the PWM value of the DC motor 50 so that 1/3 to 1/2 of this extension torque is assisted by the assist device S.

When the knee joint is extended at a constant speed in step S7, the CPU 42 then uses the extension target angle data stored in the storage unit to extend the knee joint as shown in FIG. 3 (d). It is monitored whether or not it has been extended to the target angle, that is, whether or not the angle α has reached the target extension angle (for example, 0 °) based on the knee joint angle data (step S8). If the knee joint has not yet been extended to the extension target angle in the monitoring of step S8 (step S8; NO), the CPU 42 continues to control the DC motor 50 to assist the extension of the knee joint. On the other hand, when the knee joint is extended to the extension target angle in the monitoring of step S8 (step S8; YES), the CPU 42 then controls the DC motor 50 so as to maintain the extension state of the extension target angle (step S9). (See FIG. 3D.), Whether or not the time indicated by the above threshold time data has elapsed since the knee joint was extended to the extension target angle (in other words, whether or not the assist operation according to the embodiment is terminated). Whether or not) is monitored (step S10). In the monitoring of step S10, when the time indicated by the threshold time data has not elapsed (step S10; NO), the CPU 42 continues to control the DC motor 50 for maintaining the extension state of the extension target angle. .. On the other hand, in the monitoring of step S10, when the time indicated by the threshold time data has elapsed (step S10; YES), the CPU 42 gradually stops the assist operation according to the embodiment (step S11), and finally the DC motor. The lower leg and knee joint of patient P are opened so that the driving force from 50 is not transmitted to the link mechanism unit 3, and the knee joint is waited to be flexed by itself (step S12; FIGS. 3 (e) and 3). 3 (f).).

After that, the CPU 42 determines whether or not it is instructed to end the assist operation according to the embodiment by, for example, an operation by the patient P or the like in the operation unit 41 (step S13), and if the end instruction is not given (step S13). Step S13; NO) Return to step S4 and repeat the series of assist operations described above. On the other hand, when the end instruction is given in the determination in step S13 (step S13; YES), the CPU 42 ends the assist operation according to the embodiment. At this time, the CPU 42 stops all the operations of the drive unit 10 and opens the knee joint in preparation for removal of the assist device S itself from the patient P, for example.

When the DC motor 50 is being driven in the assist operation according to the series of embodiments described above, for example, when an emergency stop operation is performed by the operation unit 41, the CPU 42 immediately drives the driving force from the DC motor 50. Is controlled so as not to be transmitted to the link mechanism unit 3, and the knee joint is opened.

Next, the control by the CPU 42 based on the knee joint angle data in the assist operation according to the embodiment will be collectively described with reference to the timing chart of FIG.

First, during one assist operation period according to the embodiment, the knee joint angle data is obtained from the extension target angle from 90 ° (initial posture state) by a series of knee joint extension and flexion (see FIG. 3) by the patient P. It changes as shown in the uppermost part of FIG. 5 within the range (a state in which the lower leg is fully extended to the extension target angle (for example, 0 °)). Then, in response to this change, the determination based on the initial posture threshold angle data (see step S4 and step S5 in FIG. 4; NO) is performed by the CPU 42 as illustrated in the second stage from the top of FIG. The determination based on the data (see steps S8 to S10 in FIG. 4) is performed by the CPU 42 as illustrated in the third stage from the top of FIG. At this time, the knee joint is maintained in the extended state at the extension target angle at the threshold time shown in FIG. 5 (see step S9 in FIG. 4).

On the other hand, the determination regarding whether or not the assist operation according to the embodiment using the first threshold angle data is executed (see step S5 and step S10 in FIG. 4) is determined by the CPU 42 in two steps from the bottom of FIG. 5 at the timing of sandwiching the threshold time. It is done as illustrated by the eyes. At this time, in response to the determinations in steps S5 and S10, the PWM value in the DC motor 50 changes from acceleration → constant speed → deceleration of knee joint extension (FIG. 4), as illustrated in the lowermost part of FIG. It changes according to step S5 to step S11). Further, in the change of the PWM value illustrated in the lowermost part of FIG. 5, both the acceleration time and the deceleration time are set to about 0.1 seconds, and the time from the start of acceleration to the start of the above threshold time is the knee joint. This is the time during which the rotation of is assisted by the assist operation according to the embodiment.

Finally, how much the load applied to the patient P is reduced by the assist operation according to the embodiment will be described with reference to FIG. Note that FIG. 6 shows a change in the knee joint angle (real curve graph) and a change in the PWM value in the DC motor 50 (solid line) when the assist operation according to the embodiment is performed twice in each assist section shown in FIG. It is a figure which shows the change of the pulse type graph) and the myoelectric potential (more specifically, the integrated myoelectric potential in the rectus femoris muscle and the vastus medialis muscle), respectively. At this time, in FIG. 6, the change in the myoelectric potential when the assist operation according to the embodiment is performed is indicated by a series of Δ, and the change in the myoelectric potential when the assist operation according to the embodiment is not performed is ●. It is indicated by a series of. As is clear from FIG. 6, it can be seen that the muscle activity is reduced by about 25% to 45% when the assisting motion according to the embodiment is performed as compared with the case where it is not performed. Therefore, it can be determined that the load applied to the patient P is also reduced to the same extent.

As described above, according to the assist operation according to the embodiment, the extension operation after the knee joint angle becomes an angle corresponding to the first threshold angle data after starting the extension operation of the knee joint by itself is assisted. And also assist in maintaining the knee joint angle when it is level. Therefore, assistance in rehabilitation for recovery of a patient with knee joint extension failure can be efficiently performed. Further, after the assist operation according to the embodiment is started, for example, the physiotherapist or the like does not need to accompany the patient P, so that the load on the physiotherapist or the like can be reduced.

Further, since the knee joint angle is assisted to maintain the extension state which is the extension target angle (specifically, horizontal) for a predetermined threshold time, it is possible to more effectively recover from the extension failure.

Furthermore, after the extension state in which the knee joint angle is the extension target angle is maintained for a threshold time, the assist operation according to the embodiment is stopped and the knee joint is opened, so that the self-recovery of the extension failure is promoted. be able to.

Further, since all or part of the first threshold angle data and the like can be changed by the patient P and the like, by setting these values arbitrarily by the patient P and the like, the recovery of the extension failure can be more effectively performed. Can be planned. From the viewpoint of effective rehabilitation, it is desirable to configure the settings such as the first threshold angle data to be set arbitrarily rather than being automated.

Further, since it is arbitrarily possible to stop the assist operation according to the embodiment and open the knee joint, the knee joint can be protected even in an emergency.

Furthermore, the assisting motion according to the embodiment should basically be performed independently for each leg, but in the case of a patient having knee joint insufficiency in both knee joints, depending on the progress of rehabilitation, for both legs. It is also possible to perform the assist operation according to the embodiment in parallel. In this case, the assist device S according to the embodiment is attached to each leg.

Further, the programs corresponding to the flowchart shown in FIG. 4 are recorded on a recording medium such as an optical disk, or acquired and stored via a network such as the Internet, and read out and executed by a general-purpose microcomputer. Thereby, it is also possible to operate the microcomputer as the CPU 42 according to the embodiment.

As described above, the present invention can be used in the field of motion assisting devices, and is particularly remarkable when applied to the field of motion assisting devices that assist the rehabilitation of patient P with knee joint extension failure. Is obtained.

3, 8 Link mechanism 3a, 8a 1st link 3b, 8b 2nd link 3c 3rd link 4 Upper leg pad 5 Knee 6 Fixture 7 Lower leg pad 9 Crotch 10 Drive unit 16 Knee joint angle sensor 23 Belt 40 Display 41 Operation 42 CPU
50 DC motor 51 Clutch part 52 Gear part S Assist device C Chair P Patient

Claims (7)

In the motion assist device that assists the motion of the knee joint of the person being assisted in the sitting position,
Auxiliary means to assist the extension movement of the knee joint and
A knee joint angle detecting means for detecting the flexion angle of the knee joint, and
After the detected bending angle reaches the preset first threshold angle, the first drive control means for assisting the extension operation by the auxiliary means and the first drive control means.
The flexion angle detected while assisting the extension motion is a second threshold angle that advances in the extension direction of the knee joint with respect to the first threshold angle, and is a second threshold angle that is uniquely set in advance. In this case, the second drive control means assisted by the auxiliary means so that the extension state in which the bending angle is the second threshold angle is maintained.
After the extension state in which the detected flexion angle is the second threshold angle is maintained, the third drive control means for stopping the assistance by the auxiliary means and opening the knee joint, and the third drive control means.
An operation assisting device characterized by being provided with. In the operation assisting device according to claim 1,
The second drive control means is characterized in that the auxiliary means assists the knee joint so that the detected flexion angle is the second threshold angle and the extended state of the knee joint is maintained for a preset threshold time. Operation assist device. In the operation assisting device according to claim 1 or 2.
An operation assisting device characterized in that the second threshold angle is an angle uniquely set in advance as an angle corresponding to horizontal. In the operation assisting device according to any one of claims 1 to 3.
Accepts an operation for changing all or part of a preset threshold time, the first threshold angle, or the second threshold angle as the time at which the detected bending angle should be maintained at the second threshold angle. An operation assisting device characterized by further including a changing operation means. In the operation assisting device according to any one of claims 1 to 4.
A motion assisting device further comprising a stopping means for stopping the assist and opening the knee joint during the assist by the assisting means. It is a motion assisting device that assists the movement of the knee joint of the person to be assisted in the sitting position, and is an assisting means for assisting the extension motion of the knee joint, a knee joint angle detecting means, a first drive control means, and a second drive. In the operation method of the operation assist device executed in the operation assist device including the control means and the third drive control means,
A knee joint angle detecting step in which the knee joint angle detecting means detects the flexion angle of the knee joint, and
After the detected bending angle of the first drive control means and the auxiliary means reaches a preset first threshold angle, the first drive control step for assisting the extension operation and the first drive control step.
The second drive control means uniquely sets in advance that the flexion angle detected while assisting the extension movement is a second threshold angle that advances in the extension direction of the knee joint with respect to the first threshold angle. When the second threshold angle is reached, the second drive control step of assisting the bending angle by the auxiliary means so as to maintain the extended state which is the second threshold angle,
A third drive control step in which the third drive control means stops the assistance by the auxiliary means and opens the knee joint after the extended state in which the detected flexion angle is the second threshold angle is maintained. When,
A method of operating an operation assisting device , which comprises . The first drive is a computer provided as the first drive control means, the second drive control means, and the third drive control means in the operation assisting device according to any one of claims 1 to 5. An operation assisting control program characterized in that it functions as a control means, the second drive control means, and the third drive control means, respectively .

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