Fluid machine and method for detecting contact of fluid machine

Abstract

To provide a fluid apparatus capable of detecting contact on the outer surface of a hollow body, without providing a contact sensor on the surface of the hollow body.SOLUTION: A fluid apparatus 1 includes an actuator 10 storing fluid inside, and constituted so that the outer surface can be deformed by contact, a pipe 2 whose tip 2a fluid-communicates with the inside of the actuator 10, a flow sensor 3 provided in the middle of the pipe 2, for measuring a flow of fluid flowing inside the pipe 2, and a contact detection part 25 for detecting contact based on a measurement result by the flow sensor 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fluid device and a method for detecting contact of a fluid device.

Background Art

[0002] As a fluid device, an actuator that generates a force by pneumatic pressure, such as a flexible finger, is known (see, for example, Patent Document 1). The flexible finger is configured to form a hollow body that houses a fluid inside with an elastic material, and to change the shape of the hollow body by changing the internal pressure of the hollow body to grip an article.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Such a fluid device has its operation controlled by adjusting the internal pressure of the hollow body. However, for realizing higher-functional operations, it is desired to accurately detect contact on the outer surface of the hollow body. Although it is also conceivable to mount a contact sensor on the outer surface of the hollow body, in this case, problems such as an increase in the cost of the fluid device and complication of the system occur.

[0005] In particular, when a contact sensor is mounted on a flexible finger for gripping an article, it is not easy to ensure the durability of the contact sensor and the wiring connected to the contact sensor. Furthermore, there are problems with the compatibility with the object to be gripped, such as food. Moreover, when used underwater, there are problems with ensuring the water resistance of the contact sensor. That is, there is room for improvement in the conventional fluid device from the viewpoint of detecting contact without providing a contact sensor.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a fluid device that can detect contact on the outer surface of a hollow body without providing a contact sensor on the surface of the hollow body in the fluid device.

Means for Solving the Problems

[0007] The first aspect of the present invention is a hollow body having fluid accommodated therein and an outer surface configured to be deformable by contact, and a pipe having a tip portion in fluid communication with the inside of the hollow body, a flow rate sensor provided in the middle of the pipe for measuring the flow of the fluid flowing in the pipe, and a contact detection unit that detects the contact based on the measurement result by the flow rate sensor and provides a fluid device.

[0008] When the outer surface of the hollow body is deformed by contact, the inner fluid is pushed out into the pipe by the amount of deformation and flow occurs, while the pressure of the fluid hardly changes. This phenomenon is more prominent as the deformation of the hollow body due to contact is smaller. As a result, when the hollow body is in contact, it is easy to accurately detect the flow of the fluid by the flow rate sensor, while it is difficult to detect the pressure fluctuation. Therefore, according to the present invention, it is possible to detect the contact in the hollow body based on the measurement result of the flow rate sensor without providing a contact sensor.

[0009] The contact detection unit may detect the contact when a differential value of the flow rate measured by the flow rate sensor exceeds a predetermined threshold value.

[0010] According to this configuration, by comparing the differential value of the flow rate with a predetermined threshold value, it is easy to accurately detect the flow of the fluid due to contact.

[0011] a pump connected to the base end of the pipe for supplying the fluid to the inside of the hollow body via the pipe, A valve provided in the middle of the pipe, located on the side opposite to the hollow body with respect to the flow rate sensor, and configured to be able to open and close a flow path defined in the pipe, and further includes The hollow body may be configured to be operable by the fluid supplied to the inside thereof.

[0012] According to this configuration, in a fluid device in which fluid is supplied from a pump to a hollow body via a valve, the present invention is preferably implemented.

[0013] Inside the pipe, a first space is defined on the side opposite to the hollow body with respect to the flow rate sensor and is configured as a closed space excluding the communication portion to the flow rate sensor. Inside the hollow body, a second space may be defined as a closed space excluding the communication portion to the pipe.

[0014] According to this configuration, even when the second space is configured as a closed space, it is possible to detect the flow of fluid from the first space to the second space caused by the compressibility of the fluid and / or the deformation of the first space and the second space.

[0015] The hollow body may constitute a cuff wound around a blood pressure measurement portion of a subject in a cuff type blood pressure monitor.

[0016] According to this configuration, in a cuff type blood pressure monitor, the present invention is preferably implemented. In particular, compared to the case of measuring blood pressure based on the pressure fluctuation of air in the cuff by the oscillometric method, since the flow of air in the cuff can be accurately detected more easily, for example, even in the case of a subject with a weak pulse such as a thready pulse, it is easy to stably measure blood pressure.

[0017] Further includes a contact force estimation unit that estimates the contact force in the contact, The contact force estimation unit estimates the contact force from a contact force estimation function based on a signal waveform measured by the flow rate sensor, The contact force estimation function may calculate the contact force using the signal waveform of the fluid as a variable.

[0018] According to this configuration, based on the signal waveform measured by the flow rate sensor, the contact force in the hollow body can be estimated.

[0019] The apparatus further includes a pressure sensor that measures the pressure of the fluid inside the hollow body or in the pipe. The contact force estimation function further includes, as the variable, the pressure of the fluid measured by the pressure sensor. The contact force estimation unit may estimate the contact force from the contact force estimation function based on the signal waveform and the pressure of the fluid.

[0020] According to this configuration, based on the signal waveform measured by the flow rate sensor and in addition, based on the pressure of the fluid measured by the pressure sensor, the contact force on the outer surface of the hollow body can be estimated with higher accuracy. In particular, by using the pressure of the fluid for the estimation of the contact force, even when the equilibrium state is reached and the flow stops after contact, the contact force can be estimated based on the pressure of the fluid.

[0021] The apparatus may further include a contact speed estimation unit that estimates the contact speed in the contact based on the signal waveform measured by the flow rate sensor.

[0022] According to this configuration, based on the signal waveform measured by the flow rate sensor, the contact speed can be estimated. For example, the contact speed may be estimated by dividing the area at one peak of the signal waveform by time, or the contact speed may be estimated by the slope of the rising part of the one peak, or the contact speed may be estimated by the rising height of the one peak. In addition to the signal waveform measured by the flow rate sensor, the pressure of the working fluid may be used.

[0023] A plurality of the flow rate sensors may be provided.

[0024] According to this configuration, based on the plurality of measurement results by the plurality of flow rate sensors, it is easier to detect the contact in the hollow body with higher accuracy.

[0025] A plurality of pipes are respectively connected to the hollow body at a plurality of different positions. The flow rate sensors are provided in each of the plurality of pipes. The apparatus further includes a contact position estimation unit that estimates the contact position in the contact. The contact position estimation unit may estimate the contact position based on the time difference between peaks when the contact is detected in each of a plurality of signal waveforms measured by the plurality of flow rate sensors.

[0026] According to this configuration, the contact position in the hollow body can be accurately estimated. Specifically, since the difference in distance from the contact position to each of the plurality of flow rate sensors corresponds to the time difference between peaks in each signal waveform, the difference in the above distances can be estimated from the time difference between peaks based on the speed at which the flow is transmitted due to contact in the hollow body and pipes obtained in advance. Therefore, based on the positions of the plurality of flow rate sensors and the difference in the above distances, the contact position in the hollow body can be accurately estimated.

[0027] At least three pipes are respectively connected to at least three different positions of the hollow body. The flow rate sensors may be provided in each of the at least three pipes.

[0028] According to this configuration, the differences in three distances from the contact position to at least three flow rate sensors can be estimated. Therefore, based on the differences in the three distances, the contact position can be estimated two-dimensionally or three-dimensionally.

[0029] The ends of the plurality of pipes on the side opposite to the ends connected to the hollow body may be connected to each other.

[0030] According to this configuration, a plurality of flow sensors are provided in a pipe annularly connected to the hollow body. As a result, when contacting the hollow body, since the fluid flows in one direction in the pipe, while the fluid flows from the hollow body to one flow sensor, it flows from the other flow sensor to the hollow body. That is, in the plurality of flow sensors, the flow direction of the fluid with respect to the hollow body is reversed. Thereby, the fluid flow can be detected more accurately and easily, and the contact position can be estimated more accurately.

[0031] Further comprising a contact shape estimation unit for estimating the contact shape in the contact, The contact shape estimation unit may estimate the contact shape based on the signal waveform measured by the flow sensor.

[0032] According to this configuration, the contact shape with respect to the hollow body can be estimated based on the signal waveform measured by the flow sensor. That is, among the signal waveforms corresponding to the contact, since the first peak corresponds to the volume of the fluid extruded from the hollow body by the contact, the contact shape can be estimated by obtaining the area of the first peak.

[0033] The second aspect of the present invention is In a pipe in fluid communication with a hollow body in which fluid is contained inside and whose outer surface is configured to be deformable by contact, measure the flow rate of the fluid when the fluid flows, Provided is a method for detecting contact of a fluid device that detects contact of the hollow body based on the measured flow rate of the fluid.

[0034] According to this method for detecting contact of the fluid device, the effects in the above fluid device are similarly exhibited.

Effects of the Invention

[0035] According to the present invention, in a fluid device, contact on the outer surface of a hollow body can be accurately detected without providing a contact sensor on the surface of the hollow body.

Brief Description of the Drawings

[0036]

Figure 1

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Figure 10

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Figure 12

MODE FOR CARRYING OUT THE INVENTION

[0037] Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings. Note that the following description is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses. Also, the drawings are schematic, and the ratios of each dimension etc. are different from the actual ones.

[0038] [First Embodiment] FIG. 1 schematically shows the configuration of the fluid device 1 according to the first embodiment of the present invention. As shown in FIG. 1, the fluid device 1 includes an actuator 10, a pipe 2 whose tip 2a is in fluid communication with the inside of the actuator 10, a flow rate sensor 3 provided in the middle of the pipe 2, and a control device 20 that controls the operation of the fluid device 1.

[0039] A pump 4 for supplying the working fluid into the pipe 2 is connected to the base end portion 2b of the pipe 2. A valve 5 is provided between the flow rate sensor 3 and the pump 4 in the pipe 2. A pressure sensor 6 is provided between the actuator 10 and the flow rate sensor 3 in the pipe 2.

[0040] The actuator 10 is a hollow body made of an elastic material, with the working fluid accommodated (filled) inside. Its outer surface is deformable (dented) by contact and is configured to return to its original shape by elastic force when the contact is released. In this embodiment, the actuator 10 has a base 11 to which the pipe 2 is connected and a pair of gripping fingers 12 extending downward from the base 11. The gripping fingers 12 are formed in an accordion shape on the back surface 12b located on the side opposite to the opposing surface 12a facing each other.

[0041] The pipe 2 has a flow path formed inside through which the working fluid flows. The pump 4 is electronically controlled by the control device 20 to supply the working fluid into the pipe 2. The valve 5 is electronically controlled by the control device 20 and is configured to be able to open and close the flow path defined in the pipe 2. When the valve 5 is open and the pump 4 supplies the working fluid to the inside of the actuator 10 through the pipe 2, the actuator 10 deforms according to the pressure of the working fluid inside.

[0042] The flow rate sensor 3 measures the flow rate (e.g., number of molecules, weight, volume) of the working fluid passing through the flow rate sensor 3. The pressure sensor 6 measures the pressure of the working fluid in the pipe 2. In this embodiment, the flow rate sensor 3 outputs the measured flow rate of the working fluid to the control device 20 as a voltage value, and similarly, the pressure sensor 6 outputs the measured pressure of the working fluid to the control device 20 as a voltage value.

[0043] In this embodiment, when the pressure of the working fluid is low (for example, equal to the atmospheric pressure), the pair of gripping fingers 12 are curved toward the back surface 12b side and spaced apart from each other. From this state, as the pressure of the working fluid increases by supplying the working fluid to the inside of the actuator 10 by the pump 4, as shown by the two-dot chain line, the pair of gripping fingers 12 are deformed in a direction in which the back surface 12b side extends, curves toward the opposing surface 12a side, and approaches each other. Thereby, an article can be gripped between the pair of gripping fingers 12. That is, the actuator 10 is configured to be operable by the working fluid supplied to the inside. In this embodiment, air is used as the working fluid, but any fluid such as water or physiological saline may be used instead.

[0044] The control device 20 is composed of a well-known computer including a storage unit 21 such as a hard disk, an arithmetic processing unit (CPU) 22, a memory, and an input / output device, and software installed in the computer. The arithmetic processing unit 22 has a pump control unit 23, a valve control unit 24, a contact detection unit 25, a contact force estimation unit 26, a contact speed estimation unit 27, and a contact shape estimation unit 28.

[0045] The storage unit 21 stores in advance information necessary for the operation of the fluid device 1. For example, a contact detection threshold value A, a contact force estimation function f(t), a contact speed estimation function g(t), and a contact shape estimation function h(t) are stored. The pump control unit 23 and the valve control unit 24 electronically control the operation of the pump 4 and the opening and closing of the valve 5, respectively.

[0046] The contact detection unit 25 detects the contact of an article with the outer surface of the actuator 10 based on the measurement result by the flow rate sensor 3. Specifically, when the outer surface of the actuator 10 is deformed so as to be recessed by the contact, the working fluid in the actuator 10 is pushed out toward the pipe 2 side, a flow of the working fluid occurs in the pipe 2, and the contact detection unit 25 detects the contact by detecting the flow by the flow rate sensor 3.

[0047] More specifically, the contact detection unit 25 calculates a differential value of a flow rate waveform W(t) showing the change over time of a signal indicating the flow rate of the working fluid measured by the flow rate sensor 3, and detects contact when the differential value exceeds a threshold value A read from the storage unit 21. Here, t represents time. When the threshold value A is set low, the detection sensitivity of contact can be increased, and when the threshold value A is set high, it is possible to prevent the detection sensitivity of contact from becoming excessively high. That is, the detection sensitivity of contact can be appropriately set by setting the threshold value A.

[0048] The contact force estimation unit 26 estimates the contact force (external force) of the article on the actuator 10 based on the measurement result by the flow rate sensor 3. Specifically, the contact force estimation unit 26 estimates the contact force from a contact force estimation function f(t) read from the storage unit 21 based on the flow rate waveform W(t) measured by the flow rate sensor 3.

[0049] The contact force estimation function f(t) is preset by, for example, a table look-up method, an analytical method, or a neural network method based on the relationship between the measured flow rate waveform W(t) and the contact force, and is a function for estimating the contact force with the signal waveform W(t) as a variable. For example, the contact force estimation function f(t) is determined from the relationship between the height, area, and / or slope, etc. of the first peak in the measured flow rate waveform W(t) and the measured contact force.

[0050] The contact speed estimation unit 27 estimates the contact speed of the article on the actuator 10 based on the measurement result by the flow rate sensor 3. Specifically, the contact speed estimation unit 27 estimates the contact speed from a contact speed estimation function g(t) read from the storage unit 21 based on the flow rate waveform W(t) measured by the flow rate sensor 3.

[0051] The contact speed estimation function g(t) is preset based on the relationship between the measured flow rate waveform W(t) and the contact speed, for example, by a table lookup method, an analytical method, or a neural network method, and is a function for estimating the contact speed with the flow rate waveform W(t) as a variable. For example, the contact speed estimation function g(t) may estimate the contact speed by dividing the area at one peak of the flow rate waveform W(t) by the time at which the peak occurs, or may estimate the contact speed by the slope of the rising portion of the one peak, or may further estimate the contact speed by the rising height of the one peak.

[0052] The contact shape estimation unit 28 estimates the contact shape of the article contacting the actuator 10 based on the measurement result by the flow rate sensor 3. Specifically, the contact shape estimation unit 28 estimates the contact shape from the contact shape estimation function h(t) read from the storage unit 21 based on the flow rate waveform W(t) measured by the flow rate sensor 3.

[0053] The contact shape estimation function h(t) is preset based on the relationship between the measured flow rate waveform W(t) and the contact shape, for example, by a table lookup method, an analytical method, or a neural network method, and is a function for estimating the contact shape with the flow rate waveform W(t) as a variable. For example, among the flow rate waveforms W(t) corresponding to the contact, since the first peak corresponds to the volume of the working fluid pushed out from the actuator 10 into the pipe 2 by the contact, the area of the first peak may be obtained and the contact shape may be estimated based on the area.

[0054] Incidentally, if necessary, the pressure waveform P(t) of the working fluid may be added as a variable to the contact force estimation function f(t), the contact velocity estimation function g(t), and the contact shape estimation function h(t). The pressure waveform P(t) is a signal waveform showing the change over time of the signal indicating the pressure of the working fluid measured by the pressure sensor 6. In this case, these functions f(t), g(t), and h(t) are preset by, for example, the table look-up method, the analytical method, or the neural network method based on the relationship between the measured flow rate waveform W(t), the pressure waveform P(t), and the contact force, and the contact force, the contact velocity, and the contact shape may be estimated using the flow rate waveform W(t) and the pressure waveform P(t) as variables, respectively.

[0055] Next, with reference to FIG. 2, the detection of contact, the estimation of the contact force, the estimation of the contact velocity, and the estimation of the contact shape in each of the cases where the internal pressure of the actuator 10 is the atmospheric pressure, is pressurized higher than the atmospheric pressure, and is depressurized lower than the atmospheric pressure will be described. In the state shown in FIG. 2, the internal pressure of the actuator 10 is maintained at a constant value, and the pair of gripping fingers 12 stop in a shape corresponding to the internal pressure.

[0056] Also, in each graph of FIG. 2, the flow rate waveform W(t) and the pressure waveform P(t) of the working fluid are shown. The flow rate waveform W(t) is the reference value W0(V) when there is no flow of the working fluid. In the present embodiment, when the working fluid flows from the actuator 10 side to the pipe 2 side, it becomes lower than the reference value W0, and when it flows from the pipe 2 side to the actuator 10 side, it becomes higher than the reference value W0. In FIG. 2, the pressure waveform P(t) means that the lower the value, the higher the pressure.

[0057] Figures 2(a) and 2(b) show the signal waveform W(t) when the pump 4 is not operating and the internal pressure of the pipe 2 and the actuator 10 is atmospheric pressure. Figure 2(a) shows the signal waveform W(t) in a state where the valve 5 is open and the inside of the actuator 10 is in communication with the ambient atmospheric pressure, and Figure 2(b) shows the signal waveform W(t) in a state where the valve 5 is closed and the inside of the actuator 10 is separated from the ambient atmospheric pressure.

[0058] In both Figures 2(a) and 2(b), the signal waveform W(t) shows a first variation Z1, a second variation Z2, a third variation Z3, and a fourth variation Z4 in order. The first variation Z1 shows the flow of the working fluid passing through the flow rate sensor 3 when it contacts the outer surface of the actuator 10. That is, first, the flow of the working fluid pushed out from the actuator 10 to the pipe 2 due to the contact is shown as the first downwardly convex peak, and then the reverse flow of the working fluid as a reaction (for example, the excessively pushed out working fluid returns) is shown as an upwardly convex peak.

[0059] After the first variation Z1, when the contact state is maintained for a while and then the contact is released, the second variation Z2 occurs. In the second variation Z2, with the detachment of the contact, as the deformation (denting) of the actuator 10 is eliminated, the flow of the working fluid into the actuator 10 occurs. At this time, the flow in the second variation Z2 occurs longer than the flow in the first variation Z1. This is presumably because in the first variation Z1, the outer surface of the actuator 10 is maintained in a certain shape because the contact state is maintained, while in the second variation Z2, the outer surface of the actuator 10 vibrates when it restores by its own elastic force because the contact state is released.

[0060] Next, in the third variation Z3, the contact state is shown, and in the fourth variation Z4, the released contact state is shown.

[0061] Figures 2(c) and (d) show the signal waveform W(t) when the pump 4 is operating and the internal pressures of the pipe 2 and the actuator 10 are pressurized higher than the atmospheric pressure. Figure 2(c) shows the signal waveform W(t) when the valve 5 is closed and the inside of the actuator 10 is disconnected from the pump 4 side, and Figure 2(d) shows the signal waveform W(t) when the valve 5 is open and the inside of the actuator 10 is in communication with the pump 4.

[0062] Also, Figures 2(e) and (f) show the signal waveform W(t) when a negative pressure source (not shown) is connected to the base end portion 2b of the pipe 2 instead of the pump 4 and the internal pressures of the pipe 2 and the actuator 10 are depressurized lower than the atmospheric pressure. Figure 2(e) shows the signal waveform W(t) when the valve 5 is closed and the inside of the actuator 10 is disconnected from the negative pressure source side, and Figure 2(f) shows the signal waveform W(t) when the valve 5 is open and the inside of the actuator 10 is in communication with the negative pressure source.

[0063] Also in each of Figures 2(c) to (f), similar to Figures 2(a) and (b), first to fourth fluctuations Z1 to Z4 are respectively recognized, which sequentially show contact, contact release, contact, and contact release.

[0064] The contact detection unit 25 detects contact on the outer surface of the actuator 10 based on the flow rate waveform W(t). Specifically, the contact detection unit 25 detects contact when the differential value of the flow rate waveform W(t) exceeds a predetermined threshold value A, that is, when the fluctuation of the working fluid is large. Note that the method for detecting the flow of the working fluid is not limited to the differential value of the flow rate waveform W(t). For example, the change amount (slope) of the flow rate waveform (t) per unit time may be obtained, and contact may be detected based on a threshold value corresponding to the change amount, and any method can be adopted.

[0065] Further, the contact force estimation unit 26 estimates the contact force on the outer surface of the actuator 10 from the contact force estimation function f(t) based on the flow rate waveform W(t). The contact speed estimation unit 27 estimates the contact speed on the outer surface of the actuator 10 from the contact speed estimation function g(t) based on the flow rate waveform W(t). The contact shape estimation unit 28 estimates the contact shape on the outer surface of the actuator 10 from the contact shape estimation function h(t) based on the flow rate waveform W(t).

[0066] At this time, referring to the pressure waveform P(t), when corresponding to the first to fourth fluctuations Z1 to Z4 of the flow rate waveform W(t), a very small amplitude is recognized, but it is difficult to distinguish this fluctuation from the noise of the signal to detect contact. In particular, it is difficult to accurately detect a more minute contact.

[0067] However, for example, in a state where contact is maintained and becomes steady, there is no flow of the working fluid and the output of the flow rate sensor 3 becomes constant at the reference value W0. However, by using the pressure waveform P(t), the accuracy of the contact force estimation by the contact force estimation unit 26 can be improved. That is, even when the internal pressure increases in a state where it is deformed to some extent but does not deform further, such as when the actuator 10 contacts a sufficiently hard object, the increase in the contact force can be accurately estimated by using the pressure waveform P(t).

[0068] Also, in each graph of FIG. 2, when comparing the state where the valve 5 is open and the state where the valve 5 is closed, the fluctuation of the working fluid is larger when the valve 5 is open. This is presumably because the working fluid extruded from the actuator 10 can flow more easily when the space where it can move is larger.

[0069] Therefore, when the side opposite to the actuator 10 of the flow rate sensor 3, such as by providing the valve 5, is a closed space, it is preferable to sufficiently secure the volume of the closed space in order to ensure the fluidity of the working fluid.

[0070] Even when the second space V2 is configured as a closed space, it is possible to detect the flow of fluid from the first space V1 to the second space V2 caused by the compressibility of the fluid and / or the deformation of the first space V1 and the second space V2.

[0071] Strictly speaking, if the volume of either the first space V1 or the second space V2 is non-zero, in principle, the flow of fluid can be detected. If the sensitivity (signal-to-noise ratio) of the detection by the flow rate sensor is sufficient, it is not limited to the volumes of the first space V1 and the second space V2.

[0072] Figure 3 shows the flow rate waveform W(t) and the pressure waveform P(t) when contact occurs on the outer surface of the pair of gripping fingers 12 while the actuator 10 is operating. Figure 3(a) shows the operation when the internal pressure of the actuator 10 is gradually increased to close the pair of gripping fingers 12, and Figure 3(b) shows the operation when the internal pressure of the actuator 10 is gradually decreased to open the pair of gripping fingers 12.

[0073] As shown in Figure 3(a), when the pair of gripping fingers 12 are closed, that is, when the working fluid is supplied from the pump 4 into the actuator 10 through the flow rate sensor 3, even if the output of the flow rate sensor 3 exceeds the reference value W0, an amplitude can be observed in the flow rate waveform W(t) at the time of contact.

[0074] On the other hand, as shown in Figure 3(b), when the pair of gripping fingers 12 are open, that is, when the working fluid is discharged from the actuator 10 to the pipe 2 side, even if the output of the flow rate sensor 3 is below the reference value W0, an amplitude can be observed in the flow rate waveform W(t) at the time of contact. Based on these amplitudes, the contact detection unit 25 accurately detects the contact.

[0075] In the above-described embodiment, the case where one flow rate sensor 3 is used has been described as an example. However, as shown by the dashed two-dot line in FIG. 1, an additional flow rate sensor 3' may be provided. Specifically, the flow rate sensor 3 and the additional flow rate sensor 3' may be provided in the pipe 2 so as to be parallel. In this case, the detection direction of the working fluid in the additional flow rate sensor 3' may be opposite to that of the flow rate sensor 3. In this case, as shown by the dashed two-dot line in FIG. 3, since the flow rate waveform W(t) by the flow rate sensor 3 and the flow rate waveform W'(t) by the additional flow rate sensor 3' have peaks in opposite directions to each other, it is easy to detect the flow of the working fluid.

[0076] Also, in the above-described embodiment, the actuator 10 has been described as an example of the fluid device. However, as shown in FIG. 4, the present invention may be applied to the cuff 81 of the cuff-type sphygmomanometer 80. That is, the actuator 10 in the fluid device 1 may be replaced with a cuff 81 (hollow body) wound around a blood pressure measurement part such as the arm of a subject. Thereby, at the time of blood pressure measurement, the vibration (flow) by the working fluid in the cuff 81 that can occur according to the change in the internal pressure of the cuff 81 can be accurately detected by the flow rate sensor 3.

[0077] In particular, compared with the case of measuring blood pressure based on the pressure fluctuation of the air in the cuff 81 by the oscillometric method, since it is easy to accurately detect the flow of the air in the cuff 81, for example, even in the case of a subject with a weak pulse such as a thready pulse, it is easy to stably measure blood pressure. Therefore, the present invention can be preferably implemented in a sphygmomanometer.

[0078] [Second Embodiment] Next, the fluid device 30 according to the second embodiment will be described with reference to FIGS. 5 to 7. FIG. 5 schematically shows the configuration of the fluid device 30. As shown in FIG. 5, the fluid device 30 includes an elongated hollow body 31 extending from a first end portion 31a to a second end portion 31b, a first pipe 32 having a tip end portion 32a connected to the first end portion 31a, a second pipe 33 having a tip end portion 33a connected to the second end portion 31b, a first flow rate sensor 34 provided in the middle of the first pipe 32, a second flow rate sensor 35 provided in the middle of the second pipe 33, and a control device 40 for controlling the operation of the fluid device 30. The base end portions 32b of the first pipe 32 and 33b of the second pipe 33 are open to the atmosphere.

[0079] The hollow body 31 is formed of an elastic material, and when an article or the like comes into contact with the outer surface, it is dented, and when the contact state is released, it returns to its original shape by the elastic force.

[0080] The first flow rate sensor 34 and the second flow rate sensor 35 are the same as the flow rate sensor 3 of the first embodiment, measure the flow rate of the fluid flowing in the first pipe 32 and the second pipe 33, and output the flow rate as a voltage value to the control device 40. In the present embodiment, the first flow rate sensor 34 and the second flow rate sensor 35 are each arranged in such a direction as to output a voltage value lower than the reference value W0 when the fluid is pushed out from the hollow body 31 into the first pipe 32 and the second pipe 33.

[0081] The control device 40 is composed of a well-known computer including a storage unit 41 such as a hard disk, an arithmetic processing unit (CPU) 42, a memory, and an input / output device, and software installed in the computer. The arithmetic processing unit 42 has a contact detection unit 45, a contact force estimation unit 46, a contact speed estimation unit 47, a contact shape estimation unit 48, and a contact position estimation unit 49. The contact detection unit 45, the contact force estimation unit 46, the contact speed estimation unit 47, and the contact shape estimation unit 48 are the same as the contact detection unit 25, the contact force estimation unit 26, the contact speed estimation unit 27, and the contact shape estimation unit 28 in the control device 20 of the first embodiment, and the description thereof will be omitted.

[0082] That is, the control device 40 is different from the control device 20 of the first embodiment in that it does not have the pump control unit 23 and the valve control unit 24, and additionally includes a contact position estimation unit 49.

[0083] The storage unit 41 stores in advance information necessary for the operation of the fluid device 30. Similar to the control device 20, for example, a contact detection threshold value A, a contact force estimation function f(t), a contact speed estimation function g(t), and a contact shape estimation function h(t) are stored. Further, a contact position estimation function x(t) is stored in the storage unit 41.

[0084] The contact position estimation unit 49 estimates the contact position based on the time difference between the first peaks when contact is detected in the two flow rate waveforms W1(t) and W2(t) measured by the first flow rate sensor 34 and the second flow rate sensor 35.

[0085] Specifically, since the lengths of the paths from the contact position in the hollow body 31 to the first flow rate sensor 34 and the second flow rate sensor 35 can be different, the time for the fluid flow due to contact to reach the first flow rate sensor 34 and the second flow rate sensor 35 can be different. Using this time difference, the contact position estimation unit 49 estimates the contact position from the contact position estimation function x(t).

[0086] For example, as shown in FIG. 5, when contacting at a contact position Y1 close to the first end portion 31a in the longitudinal direction on the outer surface of the hollow body 31, the fluid is pushed out from the contact position Y1 toward both sides of the first end portion 31a and the second end portion 31b, and the fluid is pushed out from the hollow body 31 to the atmosphere through the first flow rate sensor 34 and the second flow rate sensor 35.

[0087] At this time, as shown in Fig. 6(a), among the first flow rate sensor 34 and the second flow rate sensor 35, the peak of the flow rate waveform W1(t) by the first flow rate sensor 34 closer to the contact position Y1 occurs earlier than the peak of the flow rate waveform W2(t) by the second flow rate sensor 35 farther from the contact position Y1. Based on this time difference Δt1, the contact position estimation unit 49 estimates the contact position Y(t) from the contact position estimation function x(t).

[0088] Fig. 7 is a graph with the time difference between peaks on the horizontal axis and the length from the central position to the contact position in the longitudinal direction of the hollow body 31 on the vertical axis. As shown in Fig. 7, the time difference between peaks and the length from the central position of the contact position are in a proportional relationship.

[0089] For example, the plot M in the graph of Fig. 7 shows that the time difference between peaks was 10 mm seconds at a position 100 cm to the right in Fig. 5 from the central position. In this case, the length of the path from the contact position to the first flow rate sensor 34 is 200 cm longer than the length of the path from the contact position to the second flow rate sensor 35. Therefore, considering that a peak of 10 mm seconds is generated due to a path difference of 200 cm, it can be seen that the flow is transmitted from the contact position at a speed of 200 m / second, resulting in a value close to the speed of sound (340 m / second).

[0090] The contact position estimation function x(t) estimates the distance from the center position to the contact position from the time difference between peaks using the speed at which the above flow is transmitted to the side where the peak occurs earlier among the first flow rate sensor 34 and the second flow rate sensor 35.

[0091] Therefore, when the contact position estimation unit 49 contacts the position Y1 in the hollow body 31, based on the time difference Δt1, it estimates the distance L1 from the central position from the contact position estimation function x(t) read from the storage unit 41. Next, since the peak occurs earlier in the first flow rate sensor 34, the contact position estimation unit 49 can estimate that the contact position Y1 is located at a position L1 away from the central position toward the first flow rate sensor 34 side.

[0092] On the other hand, when contacting the contact position Y2 which is the central position in the longitudinal direction of the outer surface of the hollow body 31, as shown in Fig. 6(b), the time difference Δt2 between the peaks of the first flow rate waveform W1(t) and the second flow rate waveform W2(t) is approximately zero. In this case, the contact position estimation unit 49 estimates, based on the time difference Δt2, from the contact position estimation function that the distance from the central position is zero. Therefore, the contact position estimation unit 49 can estimate that the contact position Y2 is at the center in the longitudinal direction of the hollow body 31.

[0093] Furthermore, when contacting the contact position Y3 close to the second end 31b in the longitudinal direction of the outer surface of the hollow body 31, as shown in Fig. 6(c), the peak of the second flow rate waveform W2(t) occurs earlier than the first flow rate waveform W1(t), and the time difference between the peaks of the first flow rate waveform W1(t) and the second flow rate waveform W2(t) is Δt3.

[0094] Therefore, the contact position estimation unit 49 estimates the distance L3 from the central position from the contact position estimation function x(t) based on the time difference Δt3. Next, the contact position estimation unit 49 can estimate that the contact position Y3 is located at a position L3 away from the central position toward the second flow rate sensor 35 side because the peak occurs earlier in the second flow rate sensor 35.

[0095] In the fluid device 30, since the flow due to contact is accurately detected based on the two flow rate waveforms W1(t) and W2(t) measured by the two flow rate sensors 34 and 35, the contact detection unit 45 can detect the contact more accurately, and the accuracy of the estimation of the contact force by the contact force estimation unit 46, the estimation of the contact speed by the contact speed estimation unit 47, and the estimation of the contact shape by the contact shape estimation unit 48 is improved.

[0096] In the above embodiment, the case where the pump 4 and the valve 5 are not provided has been described as an example. However, like the first embodiment, the pump 4 and the valve 5 may be provided in the first pipe 32 and the second pipe 33.

[0097] FIG. 8 schematically shows a fluid device 50 according to a modified example of the second embodiment. The fluid device 50 is different from the fluid device 30 in that fluid bags 51 and 52 configured as closed spaces are connected to the proximal ends 32b and 33b of the first pipe 32 and the second pipe 33 and are not vented to the atmosphere. Even in this case, similar to the fluid device 30, for each of the contact positions Y1 to Y3, each contact position Y1 to Y3 can be estimated based on the peak time differences Δt1 to Δt3 shown in FIG. 9.

[0098] Further, FIG. 10 schematically shows a fluid device 60 according to a further modified example of the second embodiment. The fluid device 60 is different from the fluid device 30 in that the proximal ends 32b and 33b of the first pipe 32 and the second pipe 33 are connected to be in fluid communication with each other by a third pipe 61, and the flow path including the hollow body 31 is configured in an annular shape. Even in this case, similar to the fluid devices 30 and 50, for each of the contact positions Y1 to Y3, each contact position Y1 to Y3 can be estimated based on the peak time differences Δt1 to Δt3 shown in FIG. 11.

[0099] In this case, the flows in the first flow rate sensor 34 and the second flow rate sensor 35 occur in opposite directions to each other, except when the contact position is at the center in the longitudinal direction. That is, in the case of the contact position Y1 close to the first end 31a, a flow from the hollow body 31 toward the first pipe 32 occurs in the first flow rate sensor 34, while a flow from the second pipe 33 toward the hollow body 31 occurs in the second flow rate sensor 35. However, even in this case, since a peak time difference occurs according to the difference in the length of the path through which the flow is transmitted, the contact position estimation unit 49 can estimate the contact position based on the peak time difference.

[0100] FIG. 12 schematically shows a fluid device 70 according to still another modified example of the second embodiment. The fluid device 70 is different from the fluid device 30 in that it includes a third pipe 76 and a third flow rate sensor 77, and further includes a wide hollow body 71 instead of the long hollow body 31.

[0101] That is, at least three pipes 32, 33, and 76 are respectively connected to at least three different locations on the hollow body 71, and based on the flow rate waveforms W1(t), W2(t), and W3(t) measured by the three flow rate sensors 34, 35, and 77, the flow due to contact can be accurately detected. Therefore, the contact by the contact detection unit 45 can be detected with higher accuracy, and the accuracy of the estimation of the contact force by the contact force estimation unit 46, the estimation of the contact speed by the contact speed estimation unit 47, and the estimation of the contact shape by the contact shape estimation unit 48 is further improved.

[0102] Also, by using the three flow rate sensors 34, 35, and 77, two or more sets of the time difference between peaks and the distance from the central position are calculated, so that the two-dimensional contact position can be estimated. Furthermore, when the three flow rate sensors 34, 35, and 77 are arranged three-dimensionally, three sets of the time difference between peaks and the distance from the central position are calculated, so that the three-dimensional contact position can be estimated. Note that the number of pipes and flow rate sensors is not limited to three, and a plurality of them, four or more, may be provided.

[0103] The present invention is not limited to the configuration described in the above embodiment, and various modifications are possible.

Description of Reference Numerals

[0104] 1, 30, 50, 60, 70, 80 Fluid equipment 2 Pipe 3 Flow rate sensor 4 Pump 5 Valve 6 Pressure sensor 10 Actuator 25 Contact detection unit 26 Contact force estimation unit 27 Contact speed estimation unit 28 Contact shape estimation unit 31 Hollow body 34 First flow rate sensor 35 Second flow rate sensor 49 Contact position estimation unit W(t) Flow rate waveform P(t) Pressure waveform f(t) Contact force estimation function g(t) Contact velocity estimation function h(t) Contact shape estimation function x(t) Contact position estimation function

Claims

1. A hollow body with fluid contained inside and an outer surface configured to be deformable by contact, A pipe with a tip in fluid communication inside the hollow body, A flow rate sensor provided in the middle of the pipe for measuring the flow of fluid flowing in the pipe, A contact detection unit for detecting the contact based on the measurement result by the flow rate sensor, Comprising: Inside the pipe, on the side opposite to the hollow body with respect to the flow rate sensor, a first space configured as a closed space is defined excluding the communication part to the flow rate sensor, A fluid device in which a second space configured as a closed space is defined inside the hollow body excluding the communication part to the pipe.

2. A hollow body with fluid contained inside and an outer surface configured to be deformable by contact, A pipe with a tip in fluid communication inside the hollow body, A flow rate sensor provided in the middle of the pipe for measuring the flow of fluid flowing in the pipe, A contact detection unit for detecting the contact based on the measurement result by the flow rate sensor, Comprising: The hollow body constitutes a cuff wound around a blood pressure measurement part of a subject in a cuff type blood pressure monitor. A fluid device.

3. A hollow body with fluid contained inside and an outer surface configured to be deformable by contact, A pipe with a tip in fluid communication inside the hollow body, A flow rate sensor provided in the middle of the pipe for measuring the flow of fluid flowing in the pipe, A contact detection unit for detecting the contact based on the measurement result by the flow rate sensor, Comprising: The fluid device further comprises a contact speed estimation unit for estimating the contact speed at the contact based on the signal waveform measured by the flow rate sensor.

4. A hollow body with fluid contained inside and an outer surface configured to be deformable by contact, A pipe with a tip in fluid communication inside the hollow body, A flow rate sensor provided in the middle of the pipe for measuring the flow of fluid flowing in the pipe, A contact detection unit for detecting the contact based on the measurement result by the flow rate sensor, Comprising: A plurality of pipes are respectively connected to the hollow body at a plurality of different positions, The flow rate sensor is provided in each of the plurality of pipes, The fluid device further comprises a contact position estimation unit for estimating the contact position at the contact. The contact position estimation unit is a fluid device that estimates the contact position based on the time difference of peaks when the contact is detected in each of a plurality of signal waveforms measured by the plurality of flow sensors.

5. The contact detection unit detects the contact when a differential value of the flow rate measured by the flow sensor exceeds a predetermined threshold value. The fluid device according to any one of claims 1 to 4.

6. A pump connected to the base end portion of the pipe and supplying the fluid into the hollow body via the pipe, A valve provided in the middle of the pipe, located on the side opposite to the hollow body with respect to the flow sensor, and configured to be able to open and close a flow path defined in the pipe further comprising The hollow body is configured to be operable by the fluid supplied to the inside. The fluid device according to any one of claims 1 to 5.

7. further comprising a contact force estimation unit that estimates the contact force in the contact, The contact force estimation unit estimates the contact force from a contact force estimation function based on the signal waveform measured by the flow sensor, The contact force estimation function calculates the contact force using the signal waveform of the fluid as a variable. The fluid device according to any one of claims 1 to 6.

8. further comprising a pressure sensor that measures the pressure of the fluid inside the hollow body or in the pipe, The contact force estimation function further includes the pressure of the fluid measured by the pressure sensor as the variable, The contact force estimation unit estimates the contact force from the contact force estimation function based on the signal waveform and the pressure of the fluid. The fluid device according to claim 7.

9. further comprising a contact shape estimation unit that estimates the contact shape in the contact, The contact shape estimation unit estimates the contact shape based on the signal waveform measured by the flow sensor. The fluid device according to any one of claims 1 to 8.

10. In a pipe in fluid communication with a hollow body having fluid contained therein and an outer surface configured to be deformable by contact, the flow rate of the fluid when the fluid flows is measured by a flow rate sensor. Here, inside the pipe, on the side opposite to the hollow body with respect to the flow rate sensor, a first space is defined as a closed space excluding the communication portion to the flow rate sensor, and inside the hollow body, a second space is defined as a closed space excluding the communication portion to the pipe. A method for detecting contact of a fluid device, which detects contact of the hollow body based on the measured flow rate of the fluid.

11. In a pipe in fluid communication with a hollow body having fluid contained therein and an outer surface configured to be deformable by contact, the flow rate of the fluid when the fluid flows is measured. Here, the hollow body constitutes a cuff wound around a blood pressure measurement portion of a subject in a cuff-type blood pressure monitor. A method for detecting contact of a fluid device, which detects contact of the hollow body based on the measured flow rate of the fluid.

12. In a pipe in fluid communication with a hollow body having fluid contained therein and an outer surface configured to be deformable by contact, the flow rate of the fluid when the fluid flows is measured. Based on the measured flow rate of the fluid, contact of the hollow body is detected. A method for detecting contact of a fluid device, which estimates a contact speed at the contact based on a signal waveform of the measured flow rate of the fluid.

13. In a pipe in fluid communication with a hollow body having fluid contained therein and an outer surface configured to be deformable by contact, the flow rate of the fluid when the fluid flows is measured by a flow rate sensor. Here, a plurality of pipes are respectively connected to a plurality of different positions of the hollow body, and the flow rate sensors are provided in each of the plurality of pipes. Based on the measured flow rate of the fluid, contact of the hollow body is detected. A method for detecting contact of a fluid device, which estimates a contact position based on a time difference of peaks when the contact is detected in each of a plurality of signal waveforms measured by the plurality of flow rate sensors.

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