阅读说明：本技术 流体压驱动器和检测单元 (Fluid pressure driver and detection unit ) 是由 樱井良 樱井秀之 于 2020-04-14 设计创作，主要内容包括：流体压驱动器(10)包括：驱动器主体部(100),其形状根据圆筒状的管的膨胀或收缩而变化,该管根据流体的压力而膨胀和收缩；以及检测单元(500),其检测驱动器主体部(100)的沿着管的长度方向的长度L。(A fluid pressure driver (10) includes: an actuator main body section (100) whose shape changes in accordance with expansion or contraction of a cylindrical tube that expands and contracts in accordance with the pressure of a fluid; and a detection unit (500) that detects the length L of the actuator main body (100) along the longitudinal direction of the tube.)

1. A fluid pressure actuator in which, in a fluid pressure actuator,

the fluid pressure driver includes:

an actuator main body portion including a cylindrical tube that expands and contracts in accordance with a pressure of a fluid, the shape of the actuator main body portion changing in accordance with the expansion or contraction of the tube; and

a detection unit that detects a length of the driver main body portion along a longitudinal direction of the tube.

2. A fluid pressure driver according to claim 1,

the detection unit includes:

a measuring section that measures an electrical characteristic of the tube; and

a length estimating unit that estimates the length based on the electrical characteristic measured by the measuring unit.

3. A fluid pressure driver according to claim 2,

the measuring section measures the resistance of the tube,

the length estimating unit estimates that the length is shorter as the resistance measured by the measuring unit is lower.

4. The fluid pressure driver according to claim 2 or 3,

the tube is formed of a rubber member containing a conductive material.

5. A fluid pressure driver according to any one of claims 1 to 4,

the actuator main body includes a sleeve covering an outer peripheral surface of the tube, and the sleeve is a stretchable structure in which a fiber cord oriented in a predetermined direction is knitted.

6. A detection unit is connected with a fluid pressure driver, wherein,

the fluid pressure driver includes a driver main body portion including a cylindrical tube that expands and contracts in accordance with a pressure of a fluid, the shape of which changes in accordance with the expansion or contraction of the tube,

the detection unit detects a length of the driver main body portion in a longitudinal direction of the tube.

Technical Field

The present invention relates to a fluid pressure actuator, and more particularly, to a fluid pressure actuator and a detection unit of a so-called myjb type.

Background

Conventionally, as a fluid pressure actuator that expands and contracts a tube using gas or liquid, a structure having a rubber tube that expands and contracts by gas pressure (or hydraulic pressure) and a sleeve that covers the outer peripheral surface of the tube (so-called "mackinje type") has been widely used.

The sleeve is a cylindrical structure in which high-tension fibers such as polyamide fibers are woven, and limits the expansion movement of the tube to a predetermined range (see patent document 1).

Documents of the prior art

Patent document

Patent document 1: international publication No. 2017/010304

Disclosure of Invention

In recent years, Internet of Things (IoT) is advancing, and in order to connect to IoT, it is desired that connected devices have various sensing functions.

For example, in the case of a fluid pressure actuator of the macjba type, the actuator main body portion expands and contracts in accordance with expansion and contraction of the tube, and therefore it is preferable to have a sensor capable of detecting the length of the actuator main body portion.

As a simple method, it is conceivable to estimate the length of the actuator main body in real time based on the pressure of the fluid supplied to the fluid pressure actuator. However, in the case of the fluid pressure actuator of the macjba type, the length of the actuator main body portion may differ depending on the magnitude of the load applied to the fluid pressure actuator, and therefore it is difficult to accurately detect (estimate) the length of the actuator main body portion from the pressure of the fluid.

The present invention has been made in view of such circumstances, and an object thereof is to provide a fluid pressure actuator and a detection unit capable of accurately detecting the length of an actuator main body in real time.

One aspect of the present invention is a fluid pressure driver (e.g., fluid pressure driver 10), wherein the fluid pressure driver includes: an actuator main body portion (actuator main body portion 100) including a cylindrical tube (tube 110) that expands and contracts in accordance with a pressure of a fluid, the shape of the tube changing in accordance with the expansion or contraction of the tube; and a detection unit (detection unit 500) that detects a length (length L) of the driver main body portion along the longitudinal direction of the tube.

One aspect of the present invention is a detection unit (detection unit 500) connected to a fluid pressure actuator (e.g., fluid pressure actuator 10) including an actuator main body portion (actuator main body portion 100) including a cylindrical tube (tube 110) that expands and contracts in accordance with a pressure of a fluid, the shape of the tube changing in accordance with the expansion or contraction of the tube, the detection unit detecting a length (length L) of the actuator main body portion along a longitudinal direction of the tube.

Drawings

Fig. 1 is a side external view of a fluid pressure driver 10 including a detection unit 500.

Fig. 2 is a side view of the fluid pressure driver 10.

Fig. 3 is an exploded perspective view of the driver main body portion 100.

Fig. 4 is a functional block diagram of a detection unit 500 that detects the length of the fluid pressure driver 10.

Fig. 5 is a diagram showing a flow of an operation of estimating the length L of the actuator main body 100 by the detection unit 500.

Fig. 6 is a graph showing a relationship between the shrinkage (%) of the actuator main body portion 100 and the resistance value (M Ω) of the tube 110.

Fig. 7A is a diagram schematically showing a state of dispersion of carbon particles contained in the tube 110 (in a state where the actuator main body portion 100 is not contracted).

Fig. 7B is a view schematically showing a state of dispersion of carbon particles contained in the tube 110 (a state in which the actuator main body portion 100 is contracted).

Fig. 8 is a side view of a modified fluid pressure actuator 10A.

Fig. 9 is a side view of a fluid pressure actuator 10B according to another modification.

Detailed Description

Hereinafter, embodiments will be described based on the drawings. The same or similar reference numerals are used for the same functions and structures, and the description thereof is appropriately omitted.

(1) Overall schematic structure of fluid pressure driver and detection unit

Fig. 1 is a side external view of a fluid pressure actuator 10 including a detection unit 500 according to the present embodiment. As shown in fig. 1, the fluid pressure actuator 10 is an actuator utilizing fluid pressure, and includes a fluid pressure in an axial direction D_AX(see fig. 2) an actuator main body 100 that extends and contracts.

The fluid pressure actuator 10 has two connection portions 20. A member 25 to be operated by the fluid pressure actuator 10 is connected to the connection portion 20. For example, members constituting limbs (upper limbs, lower limbs, and the like) of a human-shaped robot are connected to the connection portion 20.

A hose 180 is connected to the fluid pressure driver 10. The other end of the hose 180 is connected to a supply device (not shown) such as a compressor for supplying a fluid (gas or liquid). Fluid flows in and out with respect to the inside of the driver main body portion 100 via the hose 180.

Further, the detection unit 500 is connected to the fluid pressure driver 10 by using a lead wire 515. The detection unit 500 detects the axial direction D of the fluid pressure driver 10_AXLength (in the longitudinal direction).

Specifically, the detection unit 500 detects the axial direction D of the actuator main body 100_AXLength (in the longitudinal direction).

(2) Structure of fluid pressure driver

Fig. 2 is a side view of the fluid pressure driver 10. As shown in fig. 2, the fluid pressure actuator 10 includes an actuator main body portion 100, a closure mechanism 200, and a closure mechanism 300. Further, the fluid pressure actuator 10 is provided with coupling portions 20 at both ends thereof.

The actuator main body portion 100 is constituted by a tube 110 and a sleeve 120. Fluid flows into the driver main body portion 100 via the fitting 400 and the through hole 410.

The actuator main body portion 100 flows into the tube 110 by the fluid and is positioned in the axial direction D of the actuator main body portion 100_AXIs contracted upwards and in the radial direction D_RAnd (4) upward expansion. In addition, driveThe actuator main body portion 100 is configured such that the fluid flows out of the tube 110 in the axial direction D of the actuator main body portion 100_AXIs expanded in radial direction D_RAnd (4) upward shrinkage. By changing the shape of the actuator main body portion 100, the fluid pressure actuator 10 functions as an actuator.

The fluid used for driving the fluid pressure actuator 10 may be any of a gas such as air, or a liquid such as water or mineral oil, and particularly, the fluid pressure actuator 10 has high durability that can be endured even when the hydraulic drive is performed by applying a high pressure to the actuator main body 100.

The fluid pressure actuator 10 is a so-called "maiji-type", and can be applied not only to artificial muscles but also to limbs (upper limbs, lower limbs, etc.) of robots requiring higher performance (contractility). The connection portion 20 is connected to members constituting the limbs.

The closing mechanism 200 and the closing mechanism 300 close the axial direction D of the actuator main body portion 100_AXAnd (c) two end portions. Specifically, the closure mechanism 200 includes a closure member 210 and a rivet member 230. The closing member 210 closes the axial direction D of the driver main body portion 100_AXOf the end portion of (a). In addition, the caulking member 230 caulks together the driver main body portion 100 and the closure member 210. An indentation 231 is formed on the outer peripheral surface of the caulking member 230, and the indentation 231 is a mark obtained by caulking the caulking member 230 by a jig.

As the closing member 210, a metal such as stainless steel can be suitably used, but the closing member is not limited to such a metal, and a hard plastic material or the like can be used.

Further, as the caulking member 230, a metal such as an aluminum alloy, brass, or iron can be used.

The difference between the closing mechanism 200 and the closing mechanism 300 is whether or not the fitting 400 (and the passage hole 410) is provided.

The fitting 400 protrudes to mount the hose 180 connected to the driving pressure source of the fluid pressure driver 10, specifically, the supply device of gas, liquid. The fluid flowing through the fitting 400 flows into the interior of the driver main body portion 100, specifically, the interior of the tube 110, through the passage hole 410.

Fig. 3 is an exploded perspective view of the driver main body portion 100. As described above, the actuator main body portion 100 is constituted by the tube 110 and the sleeve 120.

That is, the actuator main body portion 100 includes the tube 110, and the shape changes according to expansion or contraction of the tube 110.

The tube 110 is a cylindrical tubular body that expands and contracts in accordance with the pressure of the fluid. The tube 110 is made of an elastic material such as butyl rubber to repeat contraction and expansion by a fluid. When the fluid pressure actuator 10 is hydraulically driven, it is preferable to use at least one selected from the group consisting of NBR (nitrile rubber) having high hydraulic pressure resistance, hydrogenated NBR, chloroprene rubber, and epichlorohydrin rubber.

In the present embodiment, the tube 110 is formed of a rubber member containing a conductive material (may also be referred to as a filler). For example, the tube 110 can be formed of a rubber member containing carbon particles.

The sleeve 120 is cylindrical and covers the outer circumferential surface of the tube 110. The sleeve 120 is a stretchable structure obtained by knitting fiber cords oriented in a predetermined direction, and the oriented cords are crossed to repeatedly obtain a rhombic shape. The sleeve 120 has a shape that scales deformation, limiting and following the contraction and expansion of the tube 110.

As the cord constituting the sleeve 120, a fiber cord of aromatic polyamide (aramid fiber) or polyethylene terephthalate (PET) is preferably used. However, the present invention is not limited to such a type of fiber cord, and may be a cord of high-strength fiber such as PBO fiber (polyparaphenylene benzobisoxazole).

(3) Function block structure of detection unit

Fig. 4 is a functional block diagram of a detection unit 500 that detects the length of the fluid pressure driver 10.

As described above, the detection unit 500 detects the length of the fluid pressure actuator 10 that changes in accordance with the inflow of the fluid into the actuator main body portion 100 and the outflow of the fluid from the actuator main body portion 100.

Specifically, the detection unit 500 detects the edge of the driver main body portion 100The tube 110 (see fig. 2 and 3) constituting the actuator main body portion 100 has a longitudinal direction (axial direction D)_AX) Length L of (a).

The detection unit 500 includes a measurement section 510 and a length estimation section 520.

The measuring section 510 measures the electrical characteristics of the tube 110. Therefore, the detection unit 500 and the actuator main body 100 are longitudinally oriented (in the axial direction D)_AX) Both end portions of the upper tube 110 are electrically connected. Specifically, both end portions of the tube 110 and the detection unit 500 are connected by lead wires 515.

The measuring section 510 measures the resistance of the tube 110. Specifically, the measurement unit 510 measures the longitudinal direction (axial direction D) of the tube 110 connected by the lead 515_AX) The value of the resistance between the upper ends (unit: m Ω, etc.).

The length estimation unit 520 estimates the length L of the driver main body unit 100 based on the electrical characteristics measured by the measurement unit 510.

Specifically, the length estimating unit 520 estimates the length of the pipe 110 in the longitudinal direction (axial direction D)_AX) The length L is estimated from the value of the resistance between the upper ends.

More specifically, the length estimating unit 520 estimates the length L based on the fact that the length L becomes shorter as the resistance measured by the measuring unit 510 becomes lower.

The length estimating unit 520 uses a value indicating the length L of the actuator main body 100 (tube 110) and the longitudinal direction (axial direction D) of the tube 110_AX) The length L is estimated by a mathematical expression (or table) of the relationship of the values of the resistances between the upper ends. The length L is further described later.

In fig. 4, the fluid pressure actuator 10 and the detection unit 500 are shown as separate bodies, but the detection unit 500 may be incorporated into the fluid pressure actuator 10 or incorporated into the fluid pressure actuator 10. In addition, the detection unit 500 is preferably connected to a communication network such as an IoT.

(4) Actuation of fluid pressure driver and detection unit

Next, the operation of the fluid pressure actuator 10 and the detection unit 500 will be described. Specifically, the operation of estimating the length L of the actuator main body 100 as the actuator main body 100 expands and contracts will be described.

Fig. 5 shows an operation flow of estimating the length L of the actuator main body 100 by the detection unit 500.

As shown in fig. 5, in order to operate the fluid pressure actuator 10, fluid is introduced into the fluid pressure actuator 10 or fluid is discharged from the fluid pressure actuator 10 (S10).

The detection unit 500 measures the resistance of the tube 110 (S20). Specifically, as described above, the detection unit 500 measures the longitudinal direction (axial direction D) of the tube 110_AX) The value of the resistance between the upper ends.

The detection unit 500 estimates the length of the fluid pressure actuator 10, specifically, the length L of the actuator main body portion 100, based on the measured value of the resistance (S30).

The detection unit 500 repeats the processing of S20 and S30 at a predetermined cycle (for example, about 0.1 to 1 second).

Fig. 6 is a graph showing a relationship between the shrinkage (%) of the actuator main body portion 100 and the resistance value (M Ω) of the tube 110. As shown in FIG. 6, the shrinkage and the resistance are quadratic coefficients of correlation (R)²＝0.9423)。

The contraction rate (%) of the actuator main body portion 100 indicates the degree of contraction of the actuator main body portion 100 (specifically, the tube 110) with reference to the length L (0.0%) of the actuator main body portion 100 in a state where the actuator main body portion 100 is not contracted, i.e., the fluid does not flow into the actuator main body portion 100.

The reason why the negative shrinkage rate is included is that: due to the load of the member 25 coupled to the coupling portion 20 of the fluid pressure actuator 10, the actuator main body portion 100 is stretched as compared to the length L in the state where the actuator main body portion 100 is not contracted.

The detection means 500 estimates the length L using a mathematical expression, a table, or the like that can derive the relationship between the parameter that can determine the length L of the actuator main body 100 and the resistance value of the actuator main body 100 (tube 110) as shown in the graph of fig. 6.

Fig. 7A and 7B are diagrams schematically showing a state of dispersion of carbon particles contained in the tube 110.

Specifically, fig. 7A shows a dispersed state of the carbon particles 111 in a state where the actuator main body portion 100 is not contracted (a state where the contraction rate shown in fig. 6 is 0.0%).

Fig. 7B shows a dispersed state of the carbon particles 111 in a state where the driver main body portion 100 is contracted.

As shown in fig. 6, when the contraction rate of the actuator main body portion 100 becomes high, the resistance value of the actuator main body portion 100 (tube 110) becomes low. Here, when the fluid flows into the actuator main body portion 100 and the actuator main body portion 100 contracts, the tube 110 is positioned in the axial direction D within a predetermined range limited by the sleeve 120_AXIn the upward expansion, the thickness of the tube 110 becomes thin, and the distance R between the carbon particles 111 contained in the tube 110 becomes narrow (see fig. 7B).

Specifically, when the actuator main body portion 100 contracts, the tube 110 expands, and thus the film thickness of the tube 110 becomes thin. As a result, the dimension (i.e., distance R) of the carbon particles 111 in the film thickness direction becomes narrower, and the carbon particles 111 (filler) approach each other.

That is, as the contraction rate of the actuator main body portion 100 increases and the length L becomes shorter, the distance R between the carbon particles 111 becomes narrower, and therefore the electrical conductivity of the tube 110 increases, in other words, the resistance value of the tube 110 decreases.

(5) Action and Effect

According to the above embodiment, the following operational effects can be obtained. Specifically, the detection unit 500 of the fluid pressure actuator 10 detects the length L of the actuator main body portion 100 whose shape changes in accordance with the expansion or contraction of the tube 110.

Therefore, even in the case of the fluid pressure actuator 10 of the maybook type in which the length L of the actuator main body portion 100 may differ depending on the magnitude of the load (the member 25) applied to the fluid pressure actuator 10, the length L can be detected accurately and in real time.

In addition, according to the fluid pressure driver 10, the following actions and effects can also be expected. Specifically, the responsiveness during control is improved. According to the fluid pressure actuator 10, the length L can be detected by the actuator main body 100, instead of detecting the length L by an external sensor (detection means) and calculating the detection result by a calculation device (CPU) and then performing feedback control, so that the reaction rate during control is improved.

Further, if a separate sensor is mounted, the number of components increases, and the failure probability increases, but according to the fluid pressure actuator 10, the failure probability can be suppressed, and a stable operation can be expected.

In the present embodiment, the detection unit 500 includes a measurement unit 510 that measures the electrical characteristics of the tube 110, and a length estimation unit 520 that estimates the length L based on the measured electrical characteristics.

Specifically, the measuring unit 510 measures the resistance of the tube 110, and the length estimating unit 520 estimates the length L based on the fact that the length L becomes shorter as the measured resistance becomes lower.

That is, as shown in fig. 7A and 7B, when the driver main body portion 100 contracts, the distance R between the carbon particles 111 contained in the tube 110 becomes narrow, and therefore the resistance of the tube 110 becomes low. The length estimation unit 520 estimates the length L using such a phenomenon.

Further, according to the fluid pressure actuator 10, the tube 110 itself can be used for detecting the length L as compared with a fluid pressure actuator of a modification described later, and therefore, the structure is simple. Further, since the driver main body 100 does not need to incorporate a detection unit having the length L, it is lightweight and inexpensive.

In particular, the fluid pressure actuator 10 is desired to be as lightweight as possible in consideration of the fact that it is also attached to a human body, but such a lightweight requirement is easily satisfied by the fluid pressure actuator 10.

In the present embodiment, the tube 110 is formed of a rubber member containing a conductive material (carbon particles 111). Therefore, the length L of the actuator main body portion 100 can be estimated more accurately.

In the present embodiment, the sleeve 120 is a stretchable structure in which a fiber cord oriented in a predetermined direction is woven, and covers the outer circumferential surface of the tube 110. Thus, the sleeve 120 restricts and follows the contraction and expansion of the tube 110, and thus the tube 110 is deformed within a predetermined range restricted by the sleeve 120. Therefore, the range of deformation of the tube 110, i.e., the actuator main body portion 100, is limited, and therefore the length L can be measured more accurately.

(6) Other embodiments

While the present invention has been described with reference to the embodiments, it is apparent to those skilled in the art that the present invention is not limited to the above description, and various modifications and improvements can be made.

For example, the fluid pressure driver 10 may be modified as follows. Fig. 8 is a side view of a modified fluid pressure actuator 10A.

As shown in fig. 8, the fluid pressure driver 10A incorporates a detection unit 500A. The detection unit 500A includes a laser transmitter/receiver 530 and a reflector 540.

The laser transmitter/receiver 530 irradiates the laser beam toward the reflector 540, and estimates the length L of the actuator main body 100 based on the time until the laser beam reflected by the reflector 540 returns.

Fig. 9 is a side view of a fluid pressure actuator 10B according to another modification. As shown in fig. 9, the fluid pressure driver 10B incorporates a detection unit 500B. The detection unit 500B includes an ultrasonic wave transmission/reception unit 550 and a reflection unit 560.

The ultrasonic wave transmitting/receiving unit 550 transmits an ultrasonic wave signal toward the reflecting unit 560, and estimates the length L of the driver main body unit 100 based on the time until the ultrasonic wave signal reflected by the reflecting unit 560 returns.

In the above-described embodiment, the detection unit 500 measures the resistance of the tube 110, but the length L may be estimated by measuring electrical characteristics other than the resistance. For example, the detection unit 500 may measure the electrostatic capacitance of the tube 110 and estimate the length L based on the measured electrostatic capacitance.

In addition, when the conductive material, that is, when the tube 110 is formed of conductive rubber, the conductive material is not limited to the carbon particles 111 as described above, and natural rubber or synthetic rubber mixed with metal powder may be used.

As described above, although the embodiments of the present invention have been described, the present invention should not be limited by the description and drawings constituting a part of the present disclosure. Various alternative embodiments, examples, and application techniques will be apparent to those skilled in the art in light of this disclosure.

Description of the reference numerals

10. 10A, 10B, a fluid pressure driver; 20. a connecting portion; 25. a member; 100. a driver main body portion; 110. a tube; 111. carbon particles; 120. a sleeve; 180. a hose; 200. a sealing mechanism; 210. a closure member; 230. a rivet member; 231. indentation; 300. a sealing mechanism; 400. an accessory; 410. through the hole; 500. 500A, 500B, a detection unit; 510. a measurement section; 515. a lead wire; 520. a length estimation unit; 530. a laser transmitting/receiving unit; 540. a reflection section; 550. an ultrasonic wave transmitting/receiving unit; 560. a reflection part.