JP4133936B2 - Fan tube actuator and lower limb drive device - Google Patents

Description

  The present invention relates to a fan-shaped tube actuator, and more particularly to a lower limb drive device suitable for assisting movement of lower limbs (knee joints).

  Excessive rest / bed for treatment results in secondary disorders such as disuse syndrome such as joint contracture, muscle weakness, and osteoporosis.

  As one of the preventive measures for this disuse syndrome, a wearable actuator that generates physical movement by applying an unreasonable external force to an affected part that cannot be moved freely seems to be effective.

  In addition to the above-mentioned applications, depending on the purpose and ability of the user, such as a device that can directly transmit the sports skills of advanced users to others, or as a power training device for maintaining the health of the elderly The need for a wearable actuator that can change the load is expected to increase in the future.

  Therefore, the inventors of the present application have so far proposed a driveable upper limb drive system Tail-arm using a uniquely developed WTA (Wound Tube Actuator) (see Patent Document 1 below) (Non-Patent Document 1 below). reference).

  Further, an arcuate tube actuator and a joint motion support device using the same are proposed (see Patent Document 2 below).

  Hereinafter, the structure and characteristics of the wearable actuator will be described.

  The feeling of mounting is very important in designing a mounting type actuator. Therefore, paying attention to the three important points in actuator design: (i) weight, (ii) movable range, and (iii) mechanical flexibility, each parameter can be as close to the state before mounting as possible. To do.

  With regard to the weight of (i), the pneumatic actuator can maximize the output / weight ratio at present as compared with other weights. Further, by using a pneumatic actuator, a desirable structure can be obtained with respect to the mechanical flexibility of (iii).

  Therefore, the inventors of the present application first set the reduction ratio and WTA size of the tail-arm planetary gear mechanism shown as the prior art to be large, respectively, and the lower limb drive system that supports lower limb movement that requires more torque than the upper limb. I tried to develop a tail-leg.

  However, when the actually manufactured tail-leg was attached to the human body, only a maximum torque of about 5 Nm could be generated when the supply pressure was 0.4 MPa, and a large output as planned could not be obtained. This is thought to be due to the fact that, compared to the upper limb, the lower limb movement is subjected to a very large load, and the friction loss due to the wire used to convert the WTA displacement into the rotational movement is greater than expected.

  Therefore, for lower limb movement support, energy loss is greatly reduced by using an actuator that can directly generate torque, instead of converting the displacement of the actuator into rotational movement via a wire as in the tail-leg. Is desirable.

Regarding actuators that can directly generate torque, there are already proposed actuators that deform into a fan shape when pressurized, such as cloth actuators (Non-Patent Document 2 below) and oscillating pneumatic actuators (Non-Patent Document 3 below).
JP 2002-303303 A JP 2004-008449 A Tsukakoshi, Kitagawa: “Various tube-type actuators with an emphasis on fit” Vol. 34, no. 5 (2003) Kawamura: “Wearable Robot”, Nippon Fluid Power System Journal, Vol. 34, no. 5 (2003) Noritsu: “Soft Actuator”, Journal of the Robotics Society of Japan Vol. 17, no. 6 (1999)

  However, the above-described conventional actuator can directly generate torque and can be reduced during storage, but has a drawback in that the driving efficiency is reduced because the side surface swells when a load is applied during pressurization.

  Therefore, the inventors of the present application focused on an actuator that performs a bending operation by partially constraining the previously developed WTA.

  Since this actuator swells only in the target direction, it is possible to perform a bending operation efficiently. However, since this actuator also has a spiral structure, it has a drawback that the center is hollow, the contact area is small, and the driving force is small.

  In view of the above circumstances, the present invention is a fan-shaped tube actuator capable of reducing weight and improving a feeling of wearing, and capable of realizing exercise support of the lower limb that requires torque more than the upper limb with sufficient driving force, and driving the lower limb An object is to provide an apparatus.

In order to achieve the above object, the present invention provides
[1] Fan-shaped tube actuator, which is a flat tube with a hollow cross section and no pressure, is bent into a V shape, and one end of the tube bent into the V shape is bent several times in a zigzag manner. Then, the fan is formed into a closed shape by connecting with the other end of the tube bent into the V shape, and the fan is deformed into an open shape by increasing the fluid pressure in the tube. It is.

  [2] The fan-shaped tube actuator according to [1], further comprising a tube bent in the V-shape and a string having elasticity that restrains the zigzag bent portion.

  [3] The fan-shaped tube actuator according to [1], wherein a spacer for securing a fluid path is inserted into the tube so as not to seal the fluid path at a zigzag bent portion of the tube. To do.

  [4] A main body to which the fan-shaped tube actuator according to the above [1], [2] or [3] is mounted, and a first fixed to the upper leg while being fixed to the main body and centering on the knee joint. The fan-shaped tube, a second bar fixed to the lower leg, an arm fixed to the second bar, and a shaft on which the arm and the second bar are pivotally coupled. An actuator is arranged corresponding to the arm.

  [5] The lower limb drive device according to [4], wherein the pair of fan-shaped tube actuators are mounted on the left and right sides of the arm.

  According to the present invention, the following effects can be achieved.

  (1) It is possible to realize weight reduction and improved wearing feeling.

  (2) It is possible to realize exercise support for the lower limbs that require torque more than the upper limbs.

  In particular, since a large bending motion can be generated in a wide range with a light-weight structure, it is possible to exert a great effect on knee exercise support and walking support by wearing them on the body.

  A fan-shaped tube actuator, wherein a tube having a hollow cross section and a flat shape with no pressure applied is bent into a V shape, and one end of the V-shaped tube portion is bent several times in a zigzag manner in small increments, and then the V-shaped tube The fan is formed in a closed shape by connecting to the other end of the portion, and the fan is deformed so as to open by increasing the fluid pressure in the tube. Therefore, it is possible to reduce the weight and improve the wearing feeling.

  In addition, it is possible to perform exercise support for the lower limbs that require torque more than the upper limbs.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is an explanatory view of a driving principle of a fan-shaped tube actuator (also referred to as ZTA (Z-Tube Actuator)) of the present invention, FIG. 1 (a) is a side view showing a state in which the fan is closed, and FIG. 1 (b). FIG. 3 is a side view showing a state where a fan is opened. FIG. 2 is a substitute photograph of the drawing showing the driving state (the fan is opened), FIG. 3 is a diagram showing the basic motion of the fan-shaped tube actuator, and FIG. 3A is a state where the fan-shaped tube actuator is bent. FIG. 3B is a diagram showing a state in which it is inflated, and FIG. 3C is a diagram in which it is extended linearly.

  As shown in FIG. 3, this fan-shaped tube actuator is composed of a single flat tube 1 made of urethane. However, the fan-shaped tube actuator is not spirally wound like WTA, but has a crease 2 on the tube 1 in a zigzag shape. Used in the state of the bent member 3. Here, when the inside of the flat tube 1 is pressurized with air without restraining anything, the initial state of FIG. 3 (a) goes through the intermediate state of FIG. 3 (b) and FIG. 3 (c). Extends with a large stroke as in the final state.

  Therefore, as shown in FIG. 1A, this is a member 3 in which the tube 1 is extended and bent in a zigzag shape, and the bent member 3 is formed between the distal end portions 6 and 6 of the tube-shaped portion 5 of the tube. 1A, the AA line portion is tied with an elastic string 7 and is constrained so that adjacent tubes do not spread, so that the structure swells only in the bending direction as shown in FIG. When the fan-shaped tube actuator is disposed in the same space, the contact area can be larger than that of the WTA, so that a torque larger than that of the conventional curved WTA can be generated.

  Hereinafter, this fan-shaped tube actuator will be examined.

  From the tube width and length of the fan-shaped tube actuator, the theoretical maximum generated torque of the fan-shaped tube actuator is calculated.

  FIG. 4 is a schematic view of the fan-shaped tube actuator of the present invention, FIG. 4 (a) is a front view of the fan-shaped tube actuator, and FIG. 4 (b) is a side view of the fan-shaped tube actuator.

As shown in FIG. 4, when the tube width is a, the length of the bent portion is b, the radius of the arc of the side surface of the fan-shaped tube actuator is r, the distance from the rotation center is x, and the supply pressure is P, the fan-shaped tube actuator The maximum generated torque T _max is expressed by the following equation.

However, the bent portions of the fan-shaped tube actuator are all in contact with each other, and torque is applied only to the bent portions.

  Next, the operation characteristics of the prototype fan-shaped tube actuator will be described.

  A fan-shaped tube actuator was prototyped and its output was measured. The measurement results are shown in FIG. In the figure, the horizontal axis represents the load (kgf), and the vertical axis represents the output (W).

  During this measurement, the supply pressure was 0.3 MPa. Moreover, the fan-shaped tube actuator used for the measurement this time is shown in FIG. 6A is a side view of the fan-shaped tube actuator, and FIG. 6B is a substitute photograph of a top view of the fan-shaped tube actuator. In this fan-shaped tube actuator, the tube width is 37 mm, the arc radius of the side surface of the fan-shaped tube actuator is 100 mm, and the height of the folded tube of the bent portion is 43 mm.

  From this measurement result, the maximum output of the fan-shaped tube actuator was 69 W. Since the mass of the fan-shaped tube actuator used for the measurement was 44 g, the output / weight ratio was 1.6 W / g. Since the output / weight ratio of WTA used in the conventional tail-leg is 1.1 W / g, it can be seen that the fan-shaped tube actuator of the present invention has a lighter and higher output structure than the conventional WTA. .

  Further, the movable range of the fan-shaped tube actuator can be increased by increasing the number of folds in the zigzag bent portion.

  From the above considerations, it can be seen that the fan-shaped tube actuator has a structure suitable for an actuator for assisting movement of lower limbs.

  Therefore, a lower limb drive mechanism using a fan-shaped tube actuator will be described.

  7A and 7B are schematic views of the fan-shaped tube actuator driving mechanism of the present invention. FIG. 7A is a side view thereof, and FIG. 7B is a front view thereof.

  In the figure, an arm 13 sandwiched between two fan-shaped tube actuators 11 and 12 mounted in a semi-cylindrical main body 10 is integrated with a second bar 15. The first bar 14 is fixed to the semi-cylindrical main body 10. The arm 13 and the second bar 15 are pivotally attached to a shaft 16 fixed to the semi-cylindrical body 10.

  Therefore, when air pressure is applied to the inside of one fan-shaped tube actuator 11 or 12 and the air inside the other fan-shaped tube actuator 12 or 11 is discharged, the arm 13 and the second bar 15 are connected to the main body 10 and the second bar 15. It is structured to rotate relative to one bar 14.

  FIG. 8 is a view showing the operation of the fan-shaped tube actuator driving mechanism of the present invention. FIG. 8A shows a state in which the second bar is straight with respect to the first bar, and FIG. This shows a state in which the bar is bent with respect to the first bar.

  As shown in FIG. 8A, when the second bar 15 is straight with respect to the first bar 14, air is supplied to the fan-shaped tube actuator 12, and the fan of the fan-shaped tube actuator 12 is sufficiently opened. At the same time, the air of the fan-shaped tube actuator 11 is discharged so that the fan is closed.

  From that state, as shown in FIG. 8B, in order to bend the second bar 15 with respect to the first bar 14, air is supplied to the fan-shaped tube actuator 11 so that the fan opens. Accordingly, air from the fan-shaped tube actuator 12 is discharged.

  FIG. 9 is a drawing-substituting photograph showing the operating state of the fan-shaped tube actuator driving mechanism of the present invention. FIG. 9A is a state where the second bar is straight with respect to the first bar, that is, the knee joint is extended. FIG. 9B shows a state where the second bar is bent with respect to the first bar, that is, a state where the knee joint is bent.

  In these drawings, 20 is a semi-cylindrical body, 21 is a first bar fixed to the upper leg (upper knee), and 22 is a second bar fixed to the lower leg (lower knee). is there.

  Here, the fan-shaped tube actuator drive mechanism has a tube width of 37 mm, a bent portion length of 50 mm, and an arc radius of 88 mm on the side surface of the fan-shaped tube actuator. Further, the fan-shaped tube actuator drive mechanism including the body wearing appliances weighed 1.2 kg, and finished to a weight that would not hinder the wearing.

  FIG. 10 is a view showing a result of measuring the generated torque of the fan-shaped tube actuator driving mechanism of the present invention.

  In this figure, a is a curve showing the result of applying a supply pressure of 0.15 MPa, b is 0.2 MPa, c is 0.3 MPa, and d is 0.35 MPa.

  From this measurement, it was confirmed that the fan-shaped tube actuator driving mechanism was able to generate a maximum torque of 34.5 Nm when the supply pressure was 0.35 MPa.

  Considering that the torque required to lift the human knee to the horizontal is about 8 Nm, and that the torque required for the knee joint when the human stands up is about 50 Nm, the fan-shaped tube actuator drive mechanism of the present invention provides the knee joint motion. It turns out that it is effective for support.

  As described above, the present invention provides a light-weight and high-output fan-shaped tube actuator drive mechanism suitable for lower limb exercise support.

  In addition, by producing a lower limb drive mechanism using the same and measuring the generated torque, it was confirmed that this mechanism was effective in assisting the movement of the lower limbs.

  Further, in the above-described embodiment, the fan-shaped tube actuator paired with the knee joint portion is disposed, but the knee joint portion may be driven by one fan-shaped tube actuator. In that case, it is only necessary to mount a fan-shaped tube actuator as shown in FIG. 1 on the main body and open and close the fan of the single fan-shaped tube actuator.

  Further, as shown in FIG. 11, a spacer 31 (here, a thin film member) for securing a fluid path may be inserted into the tube so as not to seal the fluid path at the zigzag bent portion of the tube. Good.

  In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  The fan-shaped tube actuator and the lower limb drive device of the present invention are suitable as a knee joint reinforcement device or a knee joint support device, that is, a wearable actuator that assists human lower limb motion.

It is explanatory drawing of the drive principle of the fan-shaped tube actuator of this invention. It is a substitute photograph of drawing which shows the drive state of the fan-shaped tube actuator of this invention. It is a figure which shows the basic motion of the fan-shaped tube actuator of this invention. It is a schematic diagram of the fan-shaped tube actuator of this invention. It is a figure which shows the measurement result of the output of the fan-shaped tube actuator of this invention. It is a drawing substitute photograph which shows the example of the fan-shaped tube actuator of this invention. It is a schematic diagram of the leg drive device by the fan-shaped tube actuator of this invention. It is a figure which shows operation | movement of the fan-shaped tube actuator drive mechanism of this invention. It is a drawing substitute photograph which shows the operation state of the leg drive device by the fan-shaped tube actuator of this invention. It is a figure which shows the production | generation torque measurement result of the fan-shaped tube actuator drive mechanism of this invention. It is a figure which shows the spacer inserted in the zigzag bending part of the tube of the fan-shaped tube actuator of this invention.

Explanation of symbols

1,1 ', 1 "tube (flat)
2 Folding 3 Zigzag-shaped member 5 U-shaped portion 6, 6 'U-shaped tip portion 7 Elastic string 10, 20 Semi-cylindrical body 11, 12 Fan-shaped tube actuator 13 Arm 14 First Bar 15 Second bar 16 Axis 21 First bar fixed to upper leg (upper knee) 22 Second bar fixed to lower leg (lower knee) 31 Spacer

Claims (5)

  A tube having a hollow cross section and a flat shape with no pressure applied is bent into a V shape, one end of the tube bent into the V shape is bent several times in a zigzag manner, and then the tube is bent into the V shape. A fan-shaped tube actuator in which a fan is formed in a closed shape by connecting to the other end of the tube, and the fan is deformed into an open shape by increasing the fluid pressure in the tube.   2. The fan-shaped tube actuator according to claim 1, further comprising an elastic string that restrains the tube bent in the V shape and a zigzag bent portion.   2. The fan-shaped tube actuator according to claim 1, wherein a spacer for securing a fluid path is inserted into the tube so as not to seal the fluid path in a zigzag bent portion of the tube. .   4. A main body to which the fan-shaped tube actuator according to claim 1, 2 or 3 is mounted, a first bar fixed to the main body and fixed to the upper leg portion around the knee joint portion, and fixed to the lower leg portion. A second bar, an arm fixed to the second bar, and a shaft on which the arm and the second bar are integrally pivoted, and the fan-shaped tube actuator is disposed corresponding to the arm. A lower limb drive device characterized by:   5. The lower limb drive device according to claim 4, wherein a pair of the fan-shaped tube actuators are mounted on the left and right sides of the arm.