JP6407539B2 - Knee joint motion support device - Google Patents

Description

  Embodiments described herein relate generally to a knee joint motion support device that supports the motion of a knee joint of a human leg.

  2. Description of the Related Art Conventionally, as an apparatus that assists the movement of a knee joint, for example, an apparatus that measures an angle change of a knee joint and assists the movement based on the change pattern is known. This device starts an assist operation triggered by an operation by a person who originally needs assistance.

JP 2011-120786 A

  For this reason, for example, when lifting a heavy load on the floor, when starting the assist operation by the device, the person wearing the device needs to move the knee joint with a very large force, There was a burden on the wearer's body.

  Therefore, development of a knee joint motion support device that does not burden the wearer is desired.

Knee operation support apparatus according to the embodiment includes a brace on mounting the waist, the upper frame is positioned outside of the thigh, on which linked to rotation with respect to the upper brace the upper end of the upper frame a connecting portion, and the lower frame disposed on the outside of the lower leg portion, a lower brace which is attached to the foot near the lower end of the lower frame, connected below to linked to rotation with respect to the lower brace the lower end of the lower frame And a rotation support portion that is disposed outside the knee joint and supports the upper end of the lower frame so as to be rotatable in the direction in which the knee joint moves relative to the lower end of the upper frame. The apparatus also includes an angle sensor for detecting the rotation angle of the rotation support portion, and a given el driver to the rotation supporting portion of the driving force in a direction to assist the bending and stretching operation of the wearer, the movement of the wearer Assists by applying a driving force to the rotation support unit based on the detection results of the angle sensor and the acceleration sensor , using the acceleration sensor that detects the accompanying acceleration and the detection of the wearer's movement through the acceleration sensor as a trigger A control unit that controls the drive unit to start the operation, and a storage unit that stores statistical data obtained by statistics of the output of the angle sensor and the acceleration sensor when the wearer performs the bending and stretching operation without receiving the assist operation; It has a. When the control unit detects that the wearer has moved out of the normal operation range based on the statistical data during the assist operation , the control unit holds the driving force applied to the driving unit for a certain period of time .
The knee joint motion support device according to the embodiment includes an upper brace to be worn on the waist, an upper frame disposed along the outer side of the thigh, and an upper end of the upper frame that is pivotally connected to the upper brace. An upper connecting part, a lower frame arranged along the outer side of the lower leg, a lower brace attached to the foot near the lower end of the lower frame, and a lower end of the lower frame being rotatable with respect to the lower brace A lower connecting portion to be connected, a rotating support portion that is disposed outside the knee joint and supports the upper end of the lower frame so as to be rotatable in the direction in which the knee joint moves relative to the lower end of the upper frame; An angle sensor that detects a rotation angle, a drive unit that applies a driving force in a direction to assist a wearer's bending and stretching operations to the rotation support unit, an acceleration sensor that detects an acceleration accompanying the movement of the wearer, and the acceleration Triggers detection of wearer movement via sensor As, based on the detection result of the angle sensor and the acceleration sensor, and a control unit for controlling the driving unit so as to start the assist operation by applying a driving force to the rotation support portion. When detecting the movement of the wearer's knee outward through the acceleration sensor, the control unit assists the movement of the wearer in the direction of rising and detects the movement of closing the wearer's knee inward through the acceleration sensor. Assist the operation in the direction that the wearer squats.

FIG. 1 is a front view of a knee joint motion support device according to an embodiment. FIG. 2 is a side view of the apparatus of FIG. FIG. 3 is a block diagram of a control system for controlling the operation of the apparatus of FIG. FIG. 4 is a diagram for explaining acceleration components detected via the acceleration sensor of the apparatus of FIG. FIG. 5 is a diagram illustrating an example of statistical data stored in advance in the storage unit of the apparatus in FIG. 1. FIG. 6 is a diagram showing an assist pattern at the time of startup stored in advance in the storage unit of the apparatus of FIG. FIG. 7 is a diagram showing an assist pattern when squatting stored in advance in the storage unit of the apparatus of FIG. FIG. 8 is a flowchart for explaining the operation of the apparatus shown in FIG. FIG. 9 is a flowchart for explaining the operation of the apparatus shown in FIG. FIG. 10 is a flowchart for explaining the operation of the apparatus shown in FIG. FIG. 11 is a flowchart for explaining the operation of the apparatus shown in FIG. FIG. 12 is a side view showing a modification of the apparatus of FIG. FIG. 13 is a side view showing a modification of the apparatus of FIG. FIG. 14 is a side view showing a modification of the apparatus of FIG. FIG. 15 is a side view showing a modification of the apparatus of FIG.

Hereinafter, embodiments will be described in detail with reference to the drawings.
FIG. 1 is a front view of a knee joint motion support device 100 (hereinafter simply referred to as device 100). FIG. 2 is a side view of the device 100 as viewed from the left side of the wearer P. FIG. 3 is a block diagram of a control system that controls the operation of the apparatus 100.

  In FIG. 1, only the configuration on the left side of the apparatus 100 is shown, and the configuration on the right side is omitted. Since the apparatus 100 has a left-right symmetric configuration, only the left side configuration will be representatively described in the following description, and the description of the right side configuration will be omitted. In the following description, when viewed from the wearer P standing upright, the left-right direction is the X-axis direction, the front-rear direction is the Y-axis direction, and the up-down direction is the Z-axis direction.

  The apparatus 100 has an upper brace 2, an upper frame 4, a lower frame 6, and a lower brace 8. The upper brace 2 includes a belt that is wound around the waist of the wearer P and fixed. The upper frame 4 extends in the Z-axis direction along the outer side of the thigh of the wearer P. The lower frame 6 extends in the Z direction along the outer side of the lower leg of the wearer P. The lower brace 8 is attached to a foot and fixed near the lower end of the lower frame 6. The lower brace 8 of this embodiment is formed by, for example, forming and bending a sheet metal, and has a portion on which the sole of the foot is placed.

  The upper frame 4 and the lower frame 6 are rod-like or plate-like members formed of a light and sufficient material such as resin or light metal. If it is resin, for example, CFRP or GFRP can be used. Moreover, if it is a light metal, Al alloy, Mg alloy, Ti alloy etc. can be used, for example. In the present embodiment, the upper frame 4 is formed of a single bar, but a slide mechanism that can extend and contract its length may be provided.

  In addition, the apparatus 100 includes an upper connecting portion 3 that rotatably connects the upper end of the upper frame 4 to the upper brace 2, and a lower connecting portion that rotatably connects the lower end of the lower frame 6 to the lower brace 8. 7 and a rotation support portion 5 that rotatably supports the upper end of the lower frame 6 with respect to the lower end of the upper frame 4 outside the knee joint.

  The upper connecting portion 3 connects the upper end of the upper frame 4 to the upper brace 2 in a state where the upper connecting portion 3 can be rotated by three degrees of freedom. The rotation with three degrees of freedom referred to here includes, for example, rotation about the X axis, rotation about the Y axis, and rotation about the Z axis, and rotation in all directions. Indicates that it is possible. Specifically, the upper connecting portion 3 is a free joint such as a ball joint or a universal joint. The lower connecting portion 7 has the same configuration as the upper connecting portion 3.

  The rotation support unit 5 allows rotation in one degree of freedom around the direction in which the knee joint moves, that is, the X axis. In other words, the rotation support part 5 rotates the upper frame 4 with respect to the lower frame 6 in directions other than the direction in which the knee joint rotates (rotation about the Y axis or rotation about the Z axis). Not allowed. That is, the device 100 as a whole allows rotation with seven degrees of freedom.

  When the wearer P bends and extends the knee joint, the rotation support portion 5 rotates in accordance with the operation of the knee joint, and the upper connection portion 3 and the lower connection portion 7 also slightly rotate. That is, at the time of bending / extending operation, the knee joint opens slightly outward and the knee joint does not rotate around a simple axis, so that the upper connecting portion 3 and the lower connecting portion 7 are each rotated by 3 degrees of freedom. By allowing movement, complex movement of the knee joint is enabled. The degree of freedom of rotation of the device 100 will be described in detail later.

  A drive unit 10 is coaxially attached to the rotation support unit 5. The drive unit 10 includes a servo motor 12, an electromagnetic clutch 14, and a speed reducer. The servo motor 12 applies a driving force in a direction that assists the bending / extending operation of the wearer P wearing the apparatus 100 to the rotation support unit 5. The electromagnetic clutch 14 selectively transmits the turning force of the servo motor 12 to the rotation support unit 5. The reducer decelerates the rotation of the servo motor 12 and transmits it to the rotation support unit 5.

  When the electromagnetic clutch 14 is disengaged, the turning power of the servo motor 12 is not transmitted to the rotation support portion 5. In this embodiment, the servo motor 12 and the electromagnetic clutch 14 are arranged coaxially with the rotation support unit 5. However, for example, a configuration in which the rotational power is transmitted to the rotation support unit 5 via a bevel gear, a timing belt, or a chain is adopted. You may do it.

  The servo motor 12 is provided with a rotary encoder 16 (angle sensor) for detecting the rotation angle of the rotation support portion 5. Further, near the lower end of the lower frame 6, a holding tool 18 is provided for holding the device 100 on the crus so that the apparatus 100 does not move outward from the body side of the wearer P. Further, an acceleration sensor 22 </ b> L for detecting an acceleration accompanying the movement of the wearer P is attached to the outside of the upper frame 4 close to the rotation support portion 5.

  More specifically, the rotary encoder 16 measures the rotation angle of the servo motor 12 and detects the angle α formed by the upper frame 4 and the lower frame 6. That is, the rotary encoder 16 detects the rotation angle of the knee joint of the wearer P.

  The holder 18 restrains a part of the device 100 to the wearer P (crus) so that the device 100 does not leave the wearer P during the bending / extending operation. In particular, by restraining the vicinity of the ankle of the wearer P, it is possible to prevent the leg muscles from contracting as much as possible from bending and stretching.

  The acceleration sensor 22L is, for example, a triaxial acceleration sensor, and can detect acceleration in any direction. In particular, in the present embodiment, the acceleration sensor 22L is provided near the knee joint in order to easily detect the movement of the knee joint being opened outward or closed inward. Thus, by arranging the acceleration sensor 22L near the knee joint, the acceleration sensor 22L can accurately follow the movement of the knee joint.

  In addition to the acceleration sensor 22L, the device 100 of this embodiment includes a total of six acceleration sensors 21R, 21L, 22R, (22L), 23R, and 23L, as shown in FIG. That is, the acceleration sensors 21R and 21L are attached to the upper brace 2 at the waist height, the acceleration sensors 22R and 22L are attached to the outer surface side of the upper frame 4 in the vicinity of the rotation support portion 5, and the acceleration sensors 23R and 23L are It is attached to the outer surface side of the lower end of the lower frame 6 near the ankle. Here, the symbol R indicates the right side and L indicates the left side.

  1 and 2, in particular, only the acceleration sensor 22L (only the left side is shown) close to the knee joint is shown. The apparatus 100 of this embodiment can be controlled mainly using acceleration sensors 22R and 22L (hereinafter collectively referred to as the acceleration sensor 22) provided near the knee joint.

  Since the acceleration sensor 22 is attached near the lower end of the upper frame 4, when the knee joint angle α changes as shown in FIG. In particular, the acceleration sensor 22 rotates about the X axis as the knee joint rotates. Thereby, the direction component of the acceleration detected through the acceleration sensor 22, that is, the acceleration component in the Y-axis direction and the acceleration component in the Z-axis direction also change as indicated by the arrows in the figure. For this reason, in the following description, all the detection values by the acceleration sensor 22 are based on the acceleration sensor 22.

  As shown in FIG. 3, acceleration sensors 21 </ b> R, 22 </ b> R, 23 </ b> R, 21 </ b> L, 22 </ b> L, 23 </ b> L and a rotary encoder 16 are connected to the control unit 20 that controls the operation of the apparatus 100. Further, the servo motor 12 of the drive unit 10 and the electromagnetic clutch 14 are connected to the control unit 20. Further, a storage unit 25 is connected to the control unit 20. The control unit 20 is, for example, a PC or a control board.

  The storage unit 25 detects the angle α detected via the rotary encoder 16 and the acceleration sensor 22 when the wearer P who wears the device 100 makes a bending / extending motion without the operation assistance of the device 100. The accelerations a1, a2, and a3 are stored in association with each other. Specifically, the wearer P who wears the device 100 performs bending and stretching motions a plurality of times in advance, takes statistics of the output of the acceleration sensor 22 at each angle α, and uses the statistical data illustrated in FIG. 5 as the reference motion data. As stored in the storage unit 25 in advance.

  FIG. 5 illustrates statistical data indicating the relationship between the angle α and the acceleration a1. For example, the acceleration a1 represents the acceleration along the X-axis direction, the acceleration a2 represents the acceleration along the Y-axis direction, and the acceleration a3 represents the acceleration along the Z-axis direction. That is, the statistical data in FIG. 5 shows changes in the acceleration a1 in the X-axis direction at each angle α when bending and stretching, and shows the movement of the knee joint inward or outward during the bending and stretching movement. is there. In addition, for one acceleration sensor 22, there is statistical data related to the acceleration a2 in the Y-axis direction and statistical data related to the acceleration a3 in the Z-axis direction.

  FIG. 5 illustrates some normal distribution curves at an angle α with statistical data, and shows the average value of statistical data of acceleration a1 in association with the angle α. Further, in FIG. 5, an interval (95% confidence interval) including 95% of statistical data, which means a normal operation range, is illustrated by a broken line.

  In addition to this, a suitable assist pattern by the drive unit 10 set in advance based on the above-described statistical data is stored in the storage unit 25. FIG. 6 shows a pattern of torque T applied by the drive unit 10 to the rotation support unit 5 when the knee joint is extended from a squatting state (angle α = 0 °) to a straight standing state (angle α = 180 °). An example is shown. FIG. 7 shows an example of a torque pattern when the knee joint is bent from a straight standing state to a squatting state.

  The torque pattern when standing straight from the squatting state (FIG. 6) shows the maximum torque when starting standing from the squatting state, and the torque is zero when the angle α immediately before standing straight is about 160 °. . When the angle α approaches 180 °, the wearer P's own force alone is sufficient, and by making the torque zero at this point, it is possible to naturally start up.

  In addition, the torque pattern when squatting from a straight standing state (FIG. 7) is zero when standing straight, and the torque gradually increases as squatting, and the angle α reaches 60 °. At that time, the torque is kept constant.

Here, the freedom degree of rotation of the apparatus 100 mentioned above is demonstrated.
As described above, the upper connecting portion 3 and the lower connecting portion 7 each allow rotation with three degrees of freedom. For this reason, for example, the angle between the upper brace 2 and the upper frame 4 can be expressed by (θ _A1 , θ _A2 , θ _A3 ). In addition, the angle between the lower frame 6 and the lower brace 8 can be represented by (θ _B1 , θ _B2 , θ _B3 ).

On the other hand, assuming that the center of rotation of the upper connecting portion 3 is the origin A (0, 0, 0), and the action point B is the grounding surface of the lower brace 8 and the extended line of the connecting portion link with the lower connecting portion 7. The position and direction of the assist force acting on B can be expressed by six degrees of freedom (x, y, z, φ, θ, ψ). That is, the point B during the bending / extending operation can be expressed by the following expression using an appropriate matrix J (including the angle α) from the geometrical relationship.

From this equation, when the position (x, y, z) of the action point B with respect to the origin A is determined, the angle of the upper connecting portion 3 (θ _A1 , θ _A2 , θ _A3 ) and the angle of the lower connecting portion 7 (θ _B1 , Θ _B2 , θ _B3 ) can be seen innumerable combinations. That is, the wearer P wearing the apparatus 100 of the present embodiment can freely move the knee without changing the positional relationship between the waist and the toes (that is, the angle α of the knee joint). Specifically, even when the angle α is fixed, an operation of opening the knee outward and an operation of closing the knee inward are possible.

  On the other hand, if the upper connecting portion 3 is provided with a driving portion and only allows rotation about the X axis, the degree of freedom of rotation in the upper connecting portion 3 is 1, and the entire apparatus is as a whole. The degree of freedom of rotation is 5. In this case, when the angle of the base of the thigh and the angle of the knee joint are determined, the posture of the device is fixed and the wearer cannot move freely. The same can be said even if a drive portion is provided in the lower connecting portion 7.

  According to the present embodiment, since the upper connecting portion 3 and the lower connecting portion 7 can be rotated with three degrees of freedom, the degree of freedom of rotation of the device 100 is 7, and the operation of opening and closing the knee is performed. Is possible.

Hereinafter, with reference to the flowcharts of FIGS. 8 to 11, an assist operation by the apparatus 100 having the above-described configuration will be described.
The control unit 20 starts an operation when a switch (not shown) is turned on, and first determines the posture of the wearer P in steps 1 to 3. First, the angle α of the knee joint is detected via the rotary encoder 16, and the accelerations (a1, a2, a3) are detected via the acceleration sensor 22 (step 1). Next, when the angle α detected through the rotary encoder 16 (hereinafter simply referred to as the angle α) is smaller than a threshold value α _fl (60 ° in the present embodiment) prepared in advance for judging the squatting state. Then, the control unit 20 determines that it is in a squatting state, and proceeds to step 4 described later (step 2; YES). On the other hand, when the angle α is larger than a threshold value α _ex (160 ° in the present embodiment) prepared in advance to determine the state of standing straight, the control unit 20 determines that the device is standing. The process proceeds to Step 9 described later (Step 2; NO, Step 3; YES). Furthermore, when neither condition is satisfied, it is determined that the body is in the middle waist state, and the process proceeds to Step 22 described later (Step 2; NO, Step 3; NO).

  In steps 4 to 7, a rising intention detection process from the squatting state is performed. First, the control unit 20 issues a command to the servo motor 12 to output a posture holding torque in order to hold the posture of the wearer P squatting (step 4). Next, the angle α and the acceleration (a1, a2, a3) are detected again (step 5), and the acceleration (a1, a2, a3) indicates the normal operating range indicated as the 95% confidence interval in the statistical data of FIG. It is determined whether it has been exceeded (step 6). At this time, if the acceleration (a1, a2, a3) exceeds the 95% confidence interval in the statistical data, it is detected as a rising intention of the wearer P, and the process proceeds to step 14 to be described later in order to start the rising movement assist ( Step 6; YES). On the other hand, when the acceleration (a1, a2, a3) indicates a value within the 95% confidence interval in the statistical data, it is determined that the wearer wants to maintain the posture (step 6; NO). In that case, the state of the switch is read (step 7). If the switch is OFF, the operation is terminated (step 8; YES), and if the switch is ON, the process returns to step 4 (step 8; NO). In other words, the control unit 20 waits for input of accelerations (a1, a2, a3) exceeding the 95% confidence interval in the statistical data while outputting the attitude holding torque to the servo motor 12 as long as the switch is ON. Continue (step 6; NO, step 8; NO).

Similarly, in steps 9 to 13, a crouching intention detection process from a standing state is performed. When the wearer P stands up, the knee joint of the wearer P is hardly loaded, and the assist torque by the device 100 is not necessary. Therefore, the control unit 20 first issues a command so that the output torque of the servo motor becomes zero (step 9). Next, the angle α and the acceleration (a1, a2, a3) are detected again (step 10), and the acceleration (a1, a2, a3) shows the normal operating range indicated as the 95% confidence interval in the statistical data of FIG. It is determined whether it has been exceeded (step 11). At this time, if the acceleration (a1, a2, a3) exceeds the 95% confidence interval in the statistical data, it is detected as a crouching intention of the wearer P, and the process proceeds to step 18 described later in order to start crouching operation assist ( Step 11: YES). On the other hand, when the acceleration (a1, a2, a3) shows a value within the 95% confidence interval in the statistical data, it is determined that the wearer wants to maintain the posture (step 11; NO). In that case, the state of the switch is read (step 12). If the switch is OFF, the operation is terminated (step 13; YES), and if the switch is ON, the process returns to step 9 (step 13; NO). In other words, the control unit 20 keeps waiting for the acceleration (a1, a2, a3) exceeding the 95% confidence interval in the statistical data to be input while keeping the output torque of the servo motor 12 as long as the switch is ON. (Step 11; NO, Step 13; NO).

Further, in steps 14 to 17, the rising motion assist process shown in FIG. 9 is performed. First, the control unit 20 outputs a rising motion assist torque determined by the angle α of the knee joint (step 14). Next, the angle α and the accelerations (a1, a2, a3) are detected again (step 15), and a threshold value α _ex (160 in the present embodiment) prepared in advance to determine whether the angle α is standing straight. If greater than (°), it is determined that the vehicle is in a standing state, and the process proceeds to step 9, that is, the squatting intention detection process again as the completion of the rising motion assist (step 16; YES). On the other hand, when the angle α is equal to or less than α _ex , it is determined that the rising motion assist has not been completed (step 16; NO), and unsteady acceleration detection processing is performed (step 17). The unsteady acceleration detection process means that if any of the accelerations (a1, a2, a3) detected in step 15 exceeds the 95% confidence interval in the statistical data corresponding to the simultaneously detected angle α, The operation is detected as an unsteady operation, and the process proceeds to step 22 to be described later to cause the servo motor 12 to output a posture holding torque (step 17; YES). On the other hand, if any of the accelerations (a1, a2, a3) detected in step 15 is within the 95% confidence interval in the statistical data corresponding to the simultaneously detected angle α, the updated value of the angle α is obtained. Based on this, the servo motor 12 outputs a new rising motion assist torque (step 17; NO). That is, as long as the acceleration (a1, a2, a3) detected in step 15 is within the normal operating range at the angle α detected at the same time, the angle α as shown in FIG. 6 is maintained until the wearer stands up straight. The servo motor 12 continues to output the operation assist torque according to the change in the.

Similarly, in steps 18 to 21, a squatting operation assist process shown in FIG. 10 is performed. The control unit 20 first outputs a squatting motion assist torque determined by the angle α of the knee joint (step 18). Next, the angle α and the accelerations (a1, a2, a3) are detected again (step 19), and a threshold value α _fl (60 ° in the present embodiment) prepared in advance to determine whether the angle α is crouched. If it is smaller, it is determined that it is in a squatting state, and the process proceeds to step 4, ie, the rising intention detection process again, as the squatting operation assist is completed (step 20; YES). On the other hand, when the angle α is equal to or greater than α _fl , it is assumed that the squatting operation assistance has not been completed yet (step 20; NO), and unsteady acceleration detection processing is performed as in step 17 (step 21). If any of the accelerations (a1, a2, a3) detected in step 19 exceeds the 95% confidence interval in the statistical data corresponding to the simultaneously detected angle α, it is detected as an unsteady motion, which will be described later. Then, the process proceeds to step 22 where the servo motor 12 is caused to output the attitude holding torque (step 21; YES). On the other hand, if any of the accelerations (a1, a2, a3) detected in step 19 is within the 95% confidence interval in the statistical data corresponding to the angle α detected at the same time, the updated value of the angle α is obtained. Based on this, the servo motor 12 outputs a new squatting operation assist torque (step 21; NO). That is, as long as the acceleration (a1, a2, a3) detected in step 19 is within the normal operating range at the simultaneously detected angle α, the angle α as shown in FIG. The servo motor 12 continues to output the operation assist torque according to the change in the.

  Finally, steps 22 to 25 in FIG. 11 represent the posture maintaining process, and when it is determined that the posture is the middle waist posture in steps 2 to 3 and when the unsteady motion is detected in step 17 or step 21. Is the action. First, the control unit 20 outputs a posture holding torque corresponding to the angle α measured immediately before (step 22). Next, the angle α and the accelerations (a1, a2, a3) are detected again (step 23), and the upward instruction acceleration is detected (step 24). The detection of the acceleration for raising instruction is, for example, from the 95% confidence interval in the statistical data of the acceleration a1 in the normal operation range in which the acceleration a1 detected in step 23 is stored in the storage unit 25 in advance. If the acceleration in the direction of opening the knee is detected, it is determined that the acceleration is for ascending instruction, and the process proceeds to the rising motion assist process in step 14 (step 24; YES). On the other hand, the acceleration a1 detected in step 23 is smaller than the 95% confidence interval in the statistical data of the acceleration a1 in the posture holding state stored in advance in the storage unit 25 (a negative value having a large absolute value). That is, when acceleration in the direction of closing the knee is detected, it is determined that the acceleration is for descent instruction, and the process proceeds to the squatting operation assist process in step 18 (step 24; NO, step 25; YES). If the acceleration a1 detected in step 23 is within the 95% confidence interval in the statistical data, the process proceeds to step 22 to output the posture holding torque (step 24; NO, step 25; NO). That is, when the wearer P is not moving in the middle waist state, a constant torque is continuously output so as to maintain the posture as it is.

  According to the knee joint motion support device of the embodiment described above, since the assist operation is started using the detection of the motion of the wearer via the acceleration sensor as a trigger, there is no burden on the wearer's body.

  Further, according to the present embodiment, when an operation out of the normal operation range is detected during the assist operation, the torque is maintained and the device 100 is temporarily stopped. The apparatus 100 can be urgently stopped when an abnormal movement occurs. In this case, the wearer P is restrained by the apparatus 100 in the movement of the knee joint around the X axis, but can prevent at least a fall by freely rotating the hip joint and ankle, The safety of the wearer P can be ensured.

  Further, according to the present embodiment, in the unsteady motion detection process in steps 17 and 21, it is determined that any of the accelerations (a1, a2, a3) is out of the normal motion range as the unsteady motion. A combination may be used as a determination condition, and any acceleration may not be used for determination. For example, it is also possible to perform processing in which both a1 and a2 are out of normal operation as the determination condition for the unsteady state and the value of a3 is not used as the determination condition.

  Further, in the posture holding process shown in steps 22 to 25, statistical data of accelerations (a1, a2, a3) for performing a knee opening operation and a closing operation are prepared in advance, and the detected acceleration (a1, The fact that a2 and a3) are within the 95% confidence interval of the respective statistical data may be determined as detection of acceleration for upward instruction and detection of acceleration for downward instruction.

  Further, according to the present embodiment, in the posture holding processing shown in steps 22 to 25, the acceleration a1 corresponding to the operation of opening the knee is used as an example of the acceleration for raising instruction, and the action of closing the knee is used as the acceleration for lowering instruction. However, the present invention is not limited to this. For example, the acceleration a1 corresponding to the motion of closing the knee may be determined as a descending motion instruction, and the values of a2 and a3 are used as the determination conditions. May be used.

  Further, when it is detected that the wearer P has moved out of the normal operation range in a state where the apparatus 100 has been urgently stopped by detecting an operation out of the normal operation range as described above, the control unit 20 Alternatively, the assist operation may be switched to the direction opposite to the operation direction before the emergency stop. For example, when an operation exceeding the normal operation range is performed while standing up from the squatting state, the apparatus 100 is stopped urgently. Thereafter, when an operation exceeding the normal operation range is detected, the device 100 operates in a squatting direction. You may make it assist. Alternatively, when the operation exceeds the normal operation range while crouching from the standing state, the apparatus 100 is stopped urgently. Thereafter, when an operation exceeding the normal operation range is detected, the device 100 operates in the direction of rising. You may make it assist.

  In addition, according to the present embodiment, when the knee is moved outward from the state where the movement is stopped, the assist operation can be started in a predetermined direction (in the direction of rising in the present embodiment), and the knee is moved inward. In this case, the assisting operation can be started in the reverse direction (in the present embodiment, the squatting direction), so that the wearer P can control the device 100 simply by moving the knee in the direction intended by the wearer P, thereby improving convenience. be able to.

  Furthermore, according to this embodiment, even if the wearer P does not intend, as a result, the apparatus 100 can be automatically operated in a desired direction. For example, when the wearer P wearing the apparatus 100 lifts a heavy load from a squatting state, the wearer P imagines extending the knee joint. However, since it is difficult for the knee joint to rotate in the direction of lifting the load, when the wearer P applies force, the knee joint moves in a direction in which it easily moves, that is, a direction in which the knee is opened. In the present embodiment, since the assist operation of the apparatus 100 is started with this operation as a trigger, the assist operation can be started even if the wearer P does not intend.

  In this embodiment, the assist in the direction of standing up is started simply by moving the knee outward, and the assist in the squatting direction is started by moving the knee inward. The assist may be started only when the acceleration when the is moved exceeds the normal operation range.

  Further, in this embodiment, the assist is started when the movement of the knee is detected in a state of being stopped at the middle waist, but the assist direction may be changed using the movement of the knee as a trigger during the assist operation. Or, if you move your knee inward from a crouched state, you may assist in the direction of further squatting, and if you move your knee outward from a standing state, assist your movement in the direction of further rising. You may do it.

  In the present embodiment, the case where the acceleration sensor 22 is arranged near the lower end of the upper frame 4, that is, near the rotation holding unit 5, has been described in order to improve the detection accuracy. In this case, the arrangement position of the acceleration sensor 22 can be arbitrarily changed. For example, it may be arranged on the lower frame 6 as shown in FIG.

  Further, the holder 18 may be provided at a position where the upper frame 4 is held on the thigh as shown in FIG. 12, for example. In this case, since the upper frame 4 can be made to follow the movement of the thigh reliably, the movement of the knee of the wearer P can be measured with higher accuracy by the acceleration sensor 22.

  Moreover, you may provide the lower brace 8 in the ankle of the wearer P, for example, as shown in FIG. In this case, the apparatus 100 can be mounted more easily, and convenience can be improved.

  Further, for example, as shown in FIG. 14, it is possible to prevent the device 100 from being displaced from the wearer P at the time of bending and stretching by restraining two or more portions of the lower leg by the holders 18 and 19.

  In addition to the plurality of acceleration sensors 21, 22, 23 and the rotary encoder 16, a pressure sensor may be provided on the back side of the foot. Thereby, the movement of the center of gravity of the wearer P can be detected, and more accurate operation control can be performed.

The knee angle threshold value α _fl for detecting the squatting state and the knee angle threshold value α _ex for detecting the standing state may be freely settable. Thereby, a threshold value can be set according to the wearer P, and convenience can be further improved.

  In the above-described embodiment, the operation of the apparatus 100 is controlled mainly based on the acceleration a1 in the X-axis direction detected by the acceleration sensor 22, but based on the weighting according to the angle α, the accelerations a1, a2, The apparatus 100 may be controlled based on any one or combination of functions a3.

  In the above-described embodiment, the case where the determination criterion is whether or not the 95% confidence interval set based on the statistical data of the acceleration a1 according to the angle α is used is not limited thereto. A 99% confidence interval may be provided, or a value obtained by multiplying the average value of the acceleration a1 by a certain coefficient may be used as the determination criterion.

Although several embodiments have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.
Hereinafter, the invention described in the scope of claims at the beginning of the application of the present application will be added.
[1]
Upper brace to be worn on the waist,
An upper frame arranged along the outside of the thigh;
An upper connecting portion that rotatably connects the upper end of the upper frame to the upper brace,
A lower frame arranged along the outside of the lower leg,
Underwear to attach to the foot near the lower end of this lower frame,
A lower connecting portion that rotatably connects the lower end of the lower frame to the lower brace,
A rotation support portion disposed outside the knee joint, and rotatably supporting the upper end of the lower frame with respect to the lower end of the upper frame in a direction in which the knee joint moves;
A driving unit that applies a driving force to the rotation support unit in a direction that assists the bending and stretching operation of the wearer wearing the device;
An acceleration sensor for detecting the acceleration accompanying the movement of the wearer;
A control unit that controls the drive unit so as to start the assist operation by applying a driving force to the rotation support unit triggered by detecting the movement of the wearer via the acceleration sensor;
A knee joint movement support device.
[2]
An angle sensor for detecting a rotation angle of the rotation support portion;
The control unit controls the driving unit based on detection results by the angle sensor and the acceleration sensor.
[1] The knee joint movement support device.
[3]
A holding tool that holds the lower end side of the lower frame on the lower leg so that the device does not move outward from the body side of the wearer;
[2] Knee joint motion support device.
[4]
The upper connecting portion and the lower connecting portion each enable rotation with three degrees of freedom.
[2] Knee joint motion support device.
[5]
The drive unit is
A motor,
A speed reducer that decelerates the rotation of the motor and transmits it to the rotation support section;
[2] The knee joint motion support device according to [2].
[6]
When the motion of the wearer is detected via the acceleration sensor in a state where the wearer is crouching via the angle sensor, the control unit starts an assist operation in a direction in which the wearer stands up. ,
[2] Knee joint motion support device.
[7]
The controller starts an assist operation in a direction in which the wearer squats when detecting the wearer's movement through the acceleration sensor in a state where the wearer is standing through the angle sensor. ,
[2] Knee joint motion support device.
[8]
A storage unit that stores statistical data obtained by statistics of the output of the angle sensor and the acceleration sensor when the wearer wearing the device performs a bending and stretching operation without receiving the assist operation of the device;
When the control unit detects that the wearer has moved out of the normal operation range based on the statistical data during the assist operation by the device, the control unit holds the driving force applied to the driving unit for a certain period of time.
[2] Knee joint motion support device.
[9]
The control unit detects that the wearer has moved out of the normal operation range based on the statistical data during the assist operation by the device, and further holds the driving force applied to the driving unit. When it is detected that the wearer operates out of the normal operation range, the assist operation is switched to the assist operation in the opposite direction to the assist operation.
[8] The knee joint movement support device.
[10]
When the control unit detects an operation of opening the wearer's knee outward through the acceleration sensor, the control unit assists the operation in the direction in which the wearer stands up, and opens the wearer's knee inward through the acceleration sensor. Assists the wearer in the direction of squatting when motion is detected,
[2] Knee joint motion support device.

  2 ... Upper brace, 3 ... Upper coupling part, 4 ... Upper frame, 5 ... Rotation support part, 6 ... Lower frame, 7 ... Lower coupling part, 8 ... Lower brace, 10 ... Drive part, 12 ... Servo motor, 14 DESCRIPTION OF SYMBOLS ... Electromagnetic clutch, 16 ... Rotary encoder, 18 ... Holder, 20 ... Control part, 21, 22, 23 ... Acceleration sensor, 25 ... Memory | storage part, A ... Origin, B ... Action point, P ... Wearer, T ... Torque .

Claims (3)

Upper brace to be worn on the waist,
An upper frame arranged along the outside of the thigh;
An upper connecting portion that rotatably connects the upper end of the upper frame to the upper brace,
A lower frame arranged along the outside of the lower leg,
Underwear to attach to the foot near the lower end of this lower frame,
A lower connecting portion that rotatably connects the lower end of the lower frame to the lower brace,
A rotation support portion disposed outside the knee joint, and rotatably supporting the upper end of the lower frame with respect to the lower end of the upper frame in a direction in which the knee joint moves;
An angle sensor for detecting a rotation angle of the rotation support unit;
A drive unit that applies a driving force in a direction that assists the bending and stretching operation of the wearer to the rotation support unit;
An acceleration sensor for detecting the acceleration accompanying the movement of the wearer;
Using the detection of the wearer's movement through the acceleration sensor as a trigger, based on the detection results of the angle sensor and the acceleration sensor, a driving force is applied to the rotation support unit to start an assist operation. A control unit for controlling the driving unit;
A storage unit storing statistical data obtained by statistics of the output of the angle sensor and the acceleration sensor when the wearer bends and stretches without receiving an assist operation;
When the control unit detects that the wearer has moved out of the normal operation range based on the statistical data during the assist operation, the control unit holds the driving force applied to the driving unit for a certain period of time.
Knee joint movement support device. The control unit detects that the wearer has moved out of the normal operation range based on the statistical data during the assist operation, and further holds the driving force applied to the drive unit, When it is detected that the operation is out of the normal operation range, the assist operation is switched to the assist operation in the opposite direction to the assist operation.
The knee joint movement support apparatus according to claim 1 . Upper brace to be worn on the waist,
An upper frame arranged along the outside of the thigh;
An upper connecting portion that rotatably connects the upper end of the upper frame to the upper brace,
A lower frame arranged along the outside of the lower leg,
Underwear to attach to the foot near the lower end of this lower frame,
A lower connecting portion that rotatably connects the lower end of the lower frame to the lower brace,
A rotation support portion disposed outside the knee joint, and rotatably supporting the upper end of the lower frame with respect to the lower end of the upper frame in a direction in which the knee joint moves;
An angle sensor for detecting a rotation angle of the rotation support unit;
A drive unit that applies a driving force in a direction that assists the bending and stretching operation of the wearer to the rotation support unit;
An acceleration sensor for detecting the acceleration accompanying the movement of the wearer;
Using the detection of the wearer's movement through the acceleration sensor as a trigger, based on the detection results of the angle sensor and the acceleration sensor, a driving force is applied to the rotation support unit to start an assist operation. A control unit for controlling the drive unit,
The control unit assists the operation in the direction in which the wearer stands up when detecting an operation of opening the wearer's knee outward through the acceleration sensor, and closes the wearer's knee inward through the acceleration sensor. Assists the wearer in the direction of squatting when motion is detected,
Knee joint movement support device.