JP7698282B2 - Fluidic device and contact detection method for fluidic device - Google Patents

Description

The present invention relates to a fluid device and a contact detection method for the fluid device.

As fluid devices, actuators that generate force using air pressure, such as soft fingers, are known (see, for example, Patent Document 1). Soft fingers are configured to form a hollow body using an elastic material to hold a fluid inside, and to grip an object by changing the internal pressure of the hollow body to change the shape of the hollow body.

Special Publication No. 2020-512203

The operation of such fluidic devices is controlled by adjusting the internal pressure of the hollow body, but to achieve more sophisticated operations, it is desirable to accurately detect contact on the outer surface of the hollow body. It is possible to mount a contact sensor on the outer surface of the hollow body, but this would result in problems such as increased costs for the fluidic device and a more complicated system.

In particular, when a contact sensor is mounted on a soft finger that grasps an object, it is not easy to ensure the durability of the contact sensor and the wiring connected to the contact sensor. Furthermore, there are issues with compatibility with objects to be grasped, such as food. Furthermore, there are issues with ensuring the water resistance of the contact sensor when used underwater. In other words, there is room for improvement in conventional fluid devices in terms of detecting contact without providing a contact sensor.

The present invention was made in consideration of the above problems, and aims 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.

The first aspect of the present invention is
A hollow body containing a fluid therein and having an outer surface that is deformable upon contact;
a pipe having a tip end in fluid communication with the inside of the hollow body;
a flow rate sensor provided in the pipe to measure a flow of a fluid flowing through the pipe;
and a contact detection unit that detects the contact based on a measurement result by the flow rate sensor.

When the outer surface of a hollow body is deformed by contact, the fluid inside is pushed into the pipe by the amount of deformation, creating a flow, but the pressure of the fluid changes very little. This phenomenon is more pronounced the smaller the deformation of the hollow body due to contact. As a result, when the hollow body is in contact, it is easy to accurately detect the flow of fluid using a flow sensor, but it is difficult to detect pressure fluctuations. Therefore, according to the present invention, contact in a hollow body can be detected based on the measurement results of the flow sensor, without providing a contact sensor.

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

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

a pump connected to a base end of the pipe and configured to supply the fluid to the inside of the hollow body through the pipe;
a valve provided in the pipe on the opposite side of the hollow body with respect to the flow rate sensor and configured to open and close a flow path defined in the pipe;
The hollow body may be configured to be operable by the fluid supplied inside.

With this configuration, the present invention can be suitably implemented in a fluid device in which a fluid is supplied from a pump to a hollow body via a valve.

A first space is defined inside the pipe on the opposite side of the hollow body with respect to the flow sensor, the first space being a closed space except for a communication portion to the flow sensor,
A second space may be defined inside the hollow body, the second space being a closed space except for a portion communicating with the pipe.

With this configuration, even if 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.

The hollow body may form a cuff that is wrapped around the part of the subject whose blood pressure is to be measured in a cuff-type blood pressure monitor.

According to this configuration, the present invention can be suitably implemented in a cuff-type blood pressure monitor. In particular, compared to measuring blood pressure based on the fluctuation of air pressure in the cuff using the oscillometric method, it is easier to detect the air flow in the cuff with high accuracy, so blood pressure can be measured stably even in the case of a subject with a weak pulse, for example.

The touch panel further includes a contact force estimation unit that estimates a contact force at 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 sensor;
The contact force estimation function may calculate the contact force using the signal waveform of the fluid as a variable.

With this configuration, the contact force in the hollow body can be estimated based on the signal waveform measured by the flow sensor.

Further comprising a pressure sensor for measuring a pressure of the fluid inside the hollow body or in the pipe;
the contact force estimation function further includes, as one of the variables, a pressure of the fluid measured by the pressure sensor;
The contact force estimating unit may estimate the contact force from the contact force estimation function based on the signal waveform and the pressure of the fluid.

With this configuration, the contact force on the outer surface of the hollow body can be estimated with greater accuracy based on the fluid pressure measured by the pressure sensor in addition to the signal waveform measured by the flow sensor. In particular, by using the fluid pressure to estimate the contact force, the contact force can be estimated based on the fluid pressure even when an equilibrium state is reached after contact and no flow is observed.

The device may further include a contact speed estimation unit that estimates the contact speed at the time of contact based on the signal waveform measured by the flow sensor.

According to this configuration, the contact speed can be estimated based on the signal waveform measured by the flow sensor. For example, the contact speed may be estimated by dividing the area of one peak of the signal waveform by time, or the contact speed may be estimated from the slope of the rising part of the one peak, or the contact speed may be estimated from the rising height of the one peak. Note that the pressure of the working fluid may be used in addition to the signal waveform measured by the flow sensor.

There may be multiple flow rate sensors.

With this configuration, it is easier to detect contact in the hollow body with greater accuracy based on multiple measurement results from multiple flow sensors.

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

According to this configuration, the contact position in the hollow body can be estimated with high accuracy. Specifically, since the difference in distance from the contact position to each of the multiple flow sensors corresponds to the time difference between the peaks in the respective signal waveforms, the difference in distance can be estimated from the time difference between the peaks based on the speed at which the flow due to contact in the hollow body and piping is transmitted, which has been determined in advance. Therefore, the contact position in the hollow body can be estimated with high accuracy based on the positions of the multiple flow sensors and the difference in distance.

At least three pipes are connected to the hollow body at at least three different locations,
The flow rate sensor may be provided in each of the at least three pipes.

With this configuration, it is possible to estimate the differences in three distances from the contact position to at least three flow sensors. Therefore, it is possible to estimate the contact position in two or three dimensions based on the differences in the three distances.

The multiple pipes may be connected to each other at their ends opposite the end connected to the hollow body.

According to this configuration, multiple flow sensors are provided in a pipe that is connected in a ring shape to the hollow body. As a result, when contacting the hollow body, the fluid flows in one direction in the pipe, so that while the fluid flows from the hollow body to one of the flow sensors, it flows from the other flow sensor to the hollow body. In other words, the direction of fluid flow relative to the hollow body is reversed in the multiple flow sensors. This makes it easier to detect the fluid flow with greater accuracy, and allows the contact position to be estimated with greater accuracy.

The touch sensor further includes a contact shape estimation unit that estimates a contact shape of the touch,
The contact shape estimating unit may estimate the contact shape based on a signal waveform measured by the flow rate sensor.

With 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, since the first peak in the signal waveform corresponding to the contact corresponds to the volume of the fluid pushed out of the hollow body by the contact, the contact shape can be estimated by calculating the area of the first peak.

A second aspect of the present invention is
A flow rate of a fluid is measured in a pipe fluidically connected to a hollow body having an outer surface that is deformable by contact with the hollow body,
The present invention provides a contact detection method for a fluid device, which detects the contact of the hollow body based on the measured flow rate of the fluid.

This contact detection method for fluid devices achieves the same effects as those in the above-mentioned fluid devices.

According to the present invention, in a fluid device, contact on the outer surface of a hollow body can be detected with high accuracy without providing a contact sensor on the surface of the hollow body.

1 is a diagram illustrating a schematic diagram of a pneumatic device according to a first embodiment of the present invention; 4 is a graph showing fluctuations in the flow rate of a fluid detected by a flow sensor. 4 is a graph similar to FIG. 3 according to another example. FIG. 13 is a diagram illustrating a blood pressure monitor according to a modified example of the first embodiment. FIG. 5 is a schematic diagram showing a pneumatic device according to a second embodiment of the present invention. 4 is a graph showing fluctuations in the flow rate of a fluid detected by a flow sensor. 11 is a graph showing the relationship between the contact position and the time difference between peaks. FIG. 11 is a schematic diagram illustrating a pneumatic device according to a modified example of the second embodiment. 9 is a graph showing fluctuations in the flow rate of a fluid in the fluidic device of FIG. 8 . FIG. 13 is a diagram illustrating a pneumatic device according to a further modified example of the second embodiment. 11 is a graph showing fluctuations in the flow rate of a fluid in the fluidic device of FIG. 10 . FIG. 13 is a diagram illustrating a pneumatic device according to still another modified example of the second embodiment.

Embodiments of the present invention will now be described with reference to the accompanying drawings. Note that the following description is essentially merely illustrative and is not intended to limit the present invention, its applications, or its uses. The drawings are schematic, and the ratios of dimensions, etc., differ from the actual ones.

[First embodiment]
Fig. 1 shows a schematic configuration of a fluidic device 1 according to a first embodiment of the present invention. As shown in Fig. 1, the fluidic device 1 includes an actuator 10, a pipe 2 having a tip 2a fluidly connected to the inside of the actuator 10, a flow rate sensor 3 provided midway along the pipe 2, and a control device 20 that controls the operation of the fluidic device 1.

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

The actuator 10 is a hollow body made of an elastic material, and is filled (contains) a working fluid inside. The outer surface is deformable (deforms concavely) when contact is made, 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 piping 2 is connected, and a pair of gripping fingers 12 extending downward from the base 11. The gripping fingers 12 have a back surface 12b, located on the opposite side to the opposing surfaces 12a, which face each other, formed in an accordion shape.

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 configured to be capable of opening and closing the flow path defined within the pipe 2. When the pump 4 supplies the working fluid to the inside of the actuator 10 through the pipe 2 with the valve 5 open, the actuator 10 deforms according to the pressure of the working fluid inside.

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

In this embodiment, when the pressure of the working fluid in the actuator 10 is low (e.g., equal to the atmospheric pressure), the pair of gripping fingers 12 are curved toward the back surface 12b and separated from each other. As the pressure of the working fluid increases by supplying the working fluid to the inside of the actuator 10 from this state using the pump 4, the pair of gripping fingers 12 are deformed in a direction in which they approach each other, with the back surface 12b side extending and the pair of gripping fingers 12 curved toward the opposing surface 12a, as shown by the two-dot chain line. This allows an object to be gripped between the pair of gripping fingers 12. In other words, 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 other fluid such as water or saline may be used.

The control device 20 is composed of a well-known computer equipped with a storage unit 21 such as a hard disk, an arithmetic processing unit (CPU) 22, memory, and an input/output device, and software implemented 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.

The memory unit 21 stores information necessary for the operation of the fluid device 1 in advance, such as a contact detection threshold A, a contact force estimation function f(t), a contact speed estimation function g(t), and a contact shape estimation function h(t). 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.

The contact detection unit 25 detects contact of an object with the outer surface of the actuator 10 based on the measurement results from the flow sensor 3. Specifically, when the outer surface of the actuator 10 is deformed by being concave due to contact, the working fluid in the actuator 10 is pushed towards the pipe 2, causing a flow of the working fluid in the pipe 2, and the contact detection unit 25 detects the flow using the flow sensor 3 to detect the contact.

More specifically, the contact detection unit 25 calculates the differential value of the flow waveform W(t), which indicates the time progression of the signal indicating the flow rate of the working fluid measured by the flow sensor 3, and detects contact when the differential value exceeds the threshold value A read from the memory unit 21. t represents time. If the threshold value A is set low, the contact detection sensitivity can be increased, and if the threshold value A is set high, the contact detection sensitivity can be prevented from becoming excessively high. In other words, the contact detection sensitivity can be appropriately set by setting the threshold value A.

The contact force estimation unit 26 estimates the contact force (external force) of the article against the actuator 10 based on the measurement results from the flow sensor 3. Specifically, the contact force estimation unit 26 estimates the contact force from the contact force estimation function f(t) read out from the memory unit 21 based on the flow waveform W(t) measured by the flow sensor 3.

The contact force estimation function f(t) is preset based on the relationship between the measured flow waveform W(t) and the contact force, for example, by a table lookup method, an analytical method, or a neural network method, and is a function that estimates the contact force using the signal waveform W(t) as a variable. For example, the contact force estimation function f(t) focuses on the first peak of the measured flow waveform W(t) and is determined from the relationship between the height, area, and/or slope of this peak and the measured contact force.

The contact speed estimation unit 27 estimates the contact speed of the article with respect to the actuator 10 based on the measurement results from the flow sensor 3. Specifically, the contact speed estimation unit 27 estimates the contact speed from the contact speed estimation function g(t) read from the memory unit 21 based on the flow waveform W(t) measured by the flow sensor 3.

The contact speed estimation function g(t) is preset based on the relationship between the measured flow 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 that estimates the contact speed using the flow waveform W(t) as a variable. For example, the contact speed estimation function g(t) may estimate the contact speed by dividing the area of one peak of the flow waveform W(t) by the time at which the peak occurs, or may estimate the contact speed from the slope of the rising part of the one peak, or may further estimate the contact speed from the rising height of the one peak.

The contact shape estimation unit 28 estimates the contact shape of the item contacting the actuator 10 based on the measurement results from the flow sensor 3. Specifically, the contact shape estimation unit 28 estimates the contact shape from the contact shape estimation function h(t) read out from the memory unit 21 based on the flow waveform W(t) measured by the flow sensor 3.

The contact shape estimation function h(t) is a function that is set in advance, for example, by a table lookup method, an analytical method, or a neural network method, based on the relationship between the measured flow waveform W(t) and the contact shape, and estimates the contact shape using the flow waveform W(t) as a variable. For example, since the first peak of the flow waveform W(t) corresponding to the contact corresponds to the volume of the working fluid pushed out from the actuator 10 into the pipe 2 due to the contact, the contact shape estimation function h(t) may calculate the area of the first peak and estimate the contact shape based on the area.

If necessary, the pressure waveform P(t) of the working fluid may be added as a variable of 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 time progression 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 set in advance, for example, by a table lookup method, an analytical method, or a neural network method, based on the relationship between the actually measured flow 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 waveform W(t) and the pressure waveform P(t) as variables.

Next, referring to FIG. 2, the detection of contact, the estimation of contact force, the estimation of contact speed, and the estimation of contact shape in each of the cases where the internal pressure of the actuator 10 is atmospheric pressure, is pressurized higher than atmospheric pressure, and is depressurized lower than atmospheric pressure will be described. Note that 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 are stopped in a shape corresponding to the internal pressure.

In addition, each graph in FIG. 2 shows the flow rate waveform W(t) and pressure waveform P(t) of the working fluid. The flow rate waveform W(t) is a reference value W0 (V) when no flow of working fluid occurs, and in this embodiment, it becomes lower than the reference value W0 when the working fluid flows from the actuator 10 side to the piping 2 side, and becomes higher than the reference value W0 when the working fluid flows from the piping 2 side to the actuator 10 side. In FIG. 2, the smaller the value of the pressure waveform P(t), the higher the pressure.

Figures 2(a) and (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) when the valve 5 is open and the inside of the actuator 10 is connected to the surrounding atmospheric pressure, and Figure 2(b) shows the signal waveform W(t) when the valve 5 is closed and the inside of the actuator 10 is isolated from the surrounding atmospheric pressure.

2(a) and (b), the signal waveform W(t) shows the first fluctuation Z1, second fluctuation Z2, third fluctuation Z3, and fourth fluctuation Z4 in that order. The first fluctuation Z1 shows the flow of the working fluid passing through the flow sensor 3 when it comes into contact with the outer surface of the actuator 10. That is, the flow of the working fluid pushed out from the actuator 10 into the pipe 2 due to the contact is first shown as a downward convex peak, and then the flow of the working fluid in the opposite direction as a reaction (for example, the working fluid that was pushed out too much returns) is shown as an upward convex peak.

After the first variation Z1, when the contact state is maintained for a while and then the contact is released, a second variation Z2 occurs. In the second variation Z2, as the contact is released and the deformation (dent) of the actuator 10 is released, a flow of the working fluid occurs toward the inside of the actuator 10. At this time, the flow in the second variation Z2 occurs for longer than the flow in the first variation Z1. This is presumably because in the first variation Z1, the contact state is maintained and the outer surface of the actuator 10 is maintained in a constant shape, whereas in the second variation Z2, the contact state is released and the outer surface of the actuator 10 vibrates as it returns to its original shape due to its own elastic force.

Next, the third variation Z3 shows a contact state, and the fourth variation Z4 shows a contact-free state.

Figures 2(c) and (d) show the signal waveform W(t) when the pump 4 is operating and the internal pressure of the pipe 2 and the actuator 10 is higher than 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 separated from the pump 4, and Figure 2(d) shows the signal waveform W(t) when the valve 5 is open and the inside of the actuator 10 is connected to the pump 4.

Figures 2(e) and (f) show the signal waveform W(t) when a negative pressure source (not shown) is connected to the base end 2b of the pipe 2 instead of the pump 4, and the internal pressure of the pipe 2 and the actuator 10 is reduced below 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 isolated from the negative pressure source, and Figure 2(f) shows the signal waveform W(t) when the valve 5 is open and the inside of the actuator 10 is connected to the negative pressure source.

As in Figs. 2(a) and (b), Figs. 2(c) to (f) also show first to fourth fluctuations Z1 to Z4, which respectively indicate contact, contact elimination, contact, and contact elimination, respectively.

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

The contact force estimation unit 26 estimates the contact force on the outer surface of the actuator 10 from a contact force estimation function f(t) based on the flow waveform W(t). The contact velocity estimation unit 27 estimates the contact velocity on the outer surface of the actuator 10 from a contact velocity estimation function g(t) based on the flow waveform W(t). The contact shape estimation unit 28 estimates the contact shape on the outer surface of the actuator 10 from a contact shape estimation function h(t) based on the flow waveform W(t).

At this time, when looking at the pressure waveform P(t), a very slight amplitude is observed when it corresponds to the first to fourth fluctuations Z1 to Z4 of the flow waveform W(t), but it is difficult to distinguish this fluctuation from signal noise and detect contact. In particular, it is difficult to accurately detect even the most minute contacts.

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

In addition, in each graph in Figure 2, when comparing the state in which valve 5 is open with the state in which valve 5 is closed, the fluctuation of the working fluid is greater when valve 5 is open. This is thought to be because the working fluid can flow more easily when there is a larger space in which the working fluid pushed out from actuator 10 can move.

For this reason, when the side of the flow sensor 3 opposite the actuator 10 is made into a closed space by providing a valve 5 or the like, it is preferable to ensure that the volume of the closed space is sufficient in order to ensure the fluidity of the working fluid.

Even if 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.

In addition, to put it in extreme terms, if the volume of either the first space V1 or the second space V2 is not zero, the flow of fluid can in principle be detected, and if the detection sensitivity (signal-to-noise ratio) of the flow sensor is sufficient, there is no limitation to the volumes of the first space V1 and the second space V2.

Figure 3 shows the flow waveform W(t) and pressure waveform P(t) when contact occurs with the outer surfaces 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.

As shown in FIG. 3(a), when the pair of gripping fingers 12 is closed, that is, when the working fluid is supplied from the pump 4 to the actuator 10 through the flow sensor 3, and the output of the flow sensor 3 exceeds the reference value W0, an amplitude is observed in the flow waveform W(t) at the time of contact.

On the other hand, as shown in FIG. 3(b), when the pair of gripping fingers 12 is open, i.e., when the actuator 10 is releasing the working fluid into the pipe 2, and the output of the flow sensor 3 is below the reference value W0, amplitudes are observed in the flow waveform W(t) at the time of contact. Based on these amplitudes, the contact detection unit 25 detects contact with high accuracy.

In the above embodiment, the case where one flow sensor 3 is used has been described as an example, but an additional flow sensor 3' may be provided as shown by the two-dot chain line in FIG. 1. Specifically, the flow sensor 3 and the additional flow sensor 3' may be provided in parallel in the pipe 2. In this case, the detection direction of the working fluid in the additional flow sensor 3' may be the opposite direction to that of the flow sensor 3. In this case, as shown by the two-dot chain line in FIG. 3, the flow waveform W(t) by the flow sensor 3 and the flow waveform W'(t) by the additional flow sensor 3' have peaks in opposite directions, making it easier to detect the flow of the working fluid.

In the above embodiment, the actuator 10 has been used as an example of a fluid device, but the present invention may also be applied to the cuff 81 of a cuff-type blood pressure monitor 80, as shown in FIG. 4. That is, the actuator 10 in the fluid device 1 may be replaced with a cuff 81 (hollow body) that is wrapped around the part of the subject's body where blood pressure is to be measured, such as the subject's arm. This allows the flow sensor 3 to accurately detect vibrations (flow) caused by the working fluid in the cuff 81 that may occur due to changes in the internal pressure of the cuff 81 during blood pressure measurement.

In particular, since it is easier to detect the air flow in the cuff 81 with high accuracy compared to measuring blood pressure based on the fluctuation of air pressure in the cuff 81 using the oscillometric method, it is easier to stably measure blood pressure even in the case of a subject with a weak pulse, for example. Therefore, the present invention can be suitably implemented in a blood pressure monitor.

[Second embodiment]
Next, a fluid device 30 according to a second embodiment will be described with reference to Figs. 5 to 7. Fig. 5 shows a schematic configuration of the fluid device 30. As shown in Fig. 5, the fluid device 30 includes a long hollow body 31 extending from a first end 31a to a second end 31b, a first pipe 32 having a tip end 32a connected to the first end 31a, a second pipe 33 having a tip end 33a connected to the second end 31b, a first flow sensor 34 provided in the middle of the first pipe 32, a second flow 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. A base end 32b of the first pipe 32 and a base end 33b of the second pipe 33 are open to the atmosphere.

The hollow body 31 is made of an elastic material, and when an object or the like comes into contact with its outer surface, it becomes depressed, and when the contact is released, it returns to its original shape due to its elasticity.

The first flow sensor 34 and the second flow sensor 35 are the same as the flow sensor 3 in the first embodiment, and measure the flow rate of the fluid flowing through the first pipe 32 and the second pipe 33, and output the flow rate as a voltage value to the control device 40. In this embodiment, the first flow sensor 34 and the second flow sensor 35 are each oriented so 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.

The control device 40 is composed of a storage unit 41 such as a hard disk, a calculation processing unit (CPU) 42, a known computer equipped with a memory and an input/output device, and software implemented in the computer. The calculation 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 therefore a description thereof will be omitted.

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

The memory unit 41 stores in advance information necessary for the operation of the fluid device 30, and similar to the control device 20, stores, for example, a contact detection threshold A, a contact force estimation function f(t), a contact speed estimation function g(t), and a contact shape estimation function h(t). The memory unit 41 also stores a contact position estimation function x(t).

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 waveforms _W1 (t) and _W2 (t) measured by the first flow sensor 34 and the second flow sensor 35, respectively.

Specifically, since the length of the path from the contact position in the hollow body 31 to each of the first flow sensor 34 and the second flow sensor 35 may differ, the time it takes for the flow due to contact to be transmitted to the first flow sensor 34 and the second flow sensor 35 may differ, and the contact position estimation unit 49 uses this time difference to estimate the contact position from the contact position estimation function x(t).

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

6A, the peak of the flow waveform W _{1 (t) by the first flow sensor 34, which is closer to the contact position Y1, occurs earlier than the peak of the flow waveform W 2 (} t) by the second flow sensor 35, which is farther from the contact position Y1. Based on this time difference Δt1, the contact position estimator 49 estimates the contact position Y(t) from the contact position estimation function x(t).

Figure 7 is a graph in which the horizontal axis represents the time difference between the peaks and the vertical axis represents the length from the center position to the contact position in the longitudinal direction of the hollow body 31. As shown in Figure 7, the time difference between the peaks and the length from the center position to the contact position are in a proportional relationship.

For example, plot M in the graph of FIG. 7 indicates that the time difference between the peaks at a position 100 cm to the right of the center position in FIG. 5 was 10 ms. In this case, the length of the path from the contact position to the first flow sensor 34 is 200 cm longer than the length of the path from the contact position to the second flow sensor 35. Therefore, considering that a 10 ms peak occurs 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/s, which is roughly close to the speed of sound (340 m/s).

The contact position estimation function x(t) estimates the distance from the center position to the contact position from the time difference of the peaks, using the speed at which the flow is transmitted to the first flow sensor 34 or the second flow sensor 35, whichever occurs first.

Therefore, when contact is made at position Y1 in the hollow body 31, the contact position estimation unit 49 estimates the distance L1 from the central position from the contact position estimation function x(t) read from the memory unit 41 based on the time difference Δt1. Next, the contact position estimation unit 49 can estimate that the contact position Y1 is located at a position distance L1 away from the central position toward the first flow sensor 34 because a peak occurs early in the first flow sensor 34.

On the other hand, when contact is made at contact position Y2, which is the longitudinal center position 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 waveform _W1 (t) and the second flow waveform _W2 (t) is approximately zero. In this case, the contact position estimator 49 estimates that the distance from the central position is zero from the contact position estimation function based on the time difference Δt2. Therefore, the contact position estimator 49 can estimate that the contact position Y2 is the longitudinal center of the hollow body 31.

Furthermore, when contact is made at contact position Y3 on the outer surface of the hollow body 31, which is close to the second end 31b in the longitudinal direction, as shown in Figure 6 (c), the peak of the second flow waveform W2(t) occurs earlier than the peak of the first flow waveform _W1 (t), and the time difference between the peaks of the first flow waveform W1(t) and the second flow waveform _W2 (t) is Δt3.

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 that is the distance L3 away from the central position toward the second flow sensor 35 because a peak occurs earlier in the second flow sensor 35.

In the fluid device 30, the flow due to contact is accurately detected based on the two flow waveforms _W1 (t) and _W2 (t) measured by the two flow sensors 34, 35, so that the contact detection unit 45 can detect contact more accurately, and the accuracy of the contact force estimation by the contact force estimation unit 46, the contact velocity estimation by the contact velocity estimation unit 47, and the contact shape estimation by the contact shape estimation unit 48 is improved.

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

Figure 8 shows a schematic diagram of a fluid device 50 according to a modified example of the second embodiment. Fluid device 50 differs from fluid device 30 in that fluid bags 51, 52 configured as closed spaces are connected to base ends 32b, 33b of first pipe 32 and second pipe 33 and are not open to the atmosphere. Even in this case, as with fluid device 30, each of contact positions Y1 to Y3 can be estimated based on the time differences Δt1 to Δt3 of the peaks shown in Figure 9.

Figure 10 also shows a schematic diagram of a fluid device 60 according to a further modified example of the second embodiment. The fluid device 60 differs from the fluid device 30 in that the base ends 32b, 33b of the first pipe 32 and the second pipe 33 are connected to each other in fluid communication via a third pipe 61, and the flow path including the hollow body 31 is configured in a ring shape. Even in this case, as with the fluid devices 30 and 50, the contact positions Y1 to Y3 can be estimated based on the time differences Δt1 to Δt3 of the peaks shown in Figure 11 for each of the contact positions Y1 to Y3.

In this case, the flows in the first flow sensor 34 and the second flow sensor 35 occur in opposite directions, except when the contact position is in the center of the longitudinal direction. That is, in the case of contact position Y1 close to the first end 31a, a flow occurs in the first flow sensor 34 from the hollow body 31 toward the first pipe 32, whereas a flow occurs in the second flow sensor 35 from the second pipe 33 toward the hollow body 31. However, even in this case, a time difference in the peaks occurs according to the difference in the length of the path along which the flow travels, and the contact position estimation unit 49 can estimate the contact position based on the time difference in the peaks.

Figure 12 shows a schematic diagram of a fluid device 70 according to yet another modified example of the second embodiment. Fluid device 70 differs from 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.

That is, at least three pipes 32, 33, 76 are connected to at least three different locations on the hollow body 71, and the flow due to contact can be detected with high accuracy based on the flow waveforms _W1 (t), _W2 (t), W3(t) measured by the three flow sensors 34, ₃₅ , 77. Therefore, the contact can be detected with higher accuracy by the contact detection unit 45, and the accuracy of the estimation of the contact force by the contact force estimator 46, the estimation of the contact velocity by the contact velocity estimator 47, and the estimation of the contact shape by the contact shape estimator 48 are further improved.

In addition, by using three flow sensors 34, 35, 77, two or more sets of peak time differences and distances from the central position are calculated, making it possible to estimate a two-dimensional contact position. Furthermore, when three flow sensors 34, 35, 77 are arranged three-dimensionally, three sets of peak time differences and distances from the central position are calculated, making it possible to estimate a three-dimensional contact position. Note that the number of pipes and flow sensors is not limited to three, and multiple pipes and flow sensors may be provided, or four or more may be provided.

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

REFERENCE SIGNS LIST 1, 30, 50, 60, 70, 80 Fluid device 2 Pipe 3 Flow 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 sensor 35 Second flow sensor 49 Contact position estimation unit W(t) Flow waveform P(t) Pressure waveform f(t) Contact force estimation function g(t) Contact speed estimation function h(t) Contact shape estimation function x(t) Contact position estimation function

Claims (13)

A hollow body containing a fluid therein and having an outer surface that is deformable upon contact;
a pipe having a tip end in fluid communication with the inside of the hollow body;
a flow rate sensor provided in the pipe to measure a flow of a fluid flowing through the pipe;
a contact detection unit that detects the contact based on a measurement result by the flow rate sensor ,
A first space is defined inside the pipe on the opposite side of the hollow body with respect to the flow sensor, the first space being a closed space except for a communication portion to the flow sensor,
A fluid device , wherein a second space is defined inside the hollow body, the second space being a closed space except for a portion communicating with the pipe . A hollow body containing a fluid therein and having an outer surface that is deformable upon contact;
a pipe having a tip end in fluid communication with the inside of the hollow body;
a flow rate sensor provided in the pipe to measure a flow of a fluid flowing through the pipe;
a contact detection unit that detects the contact based on a measurement result by the flow rate sensor;
It is equipped with
The fluid device, wherein the hollow body constitutes a cuff that is wrapped around a part of a subject whose blood pressure is to be measured in a cuff-type sphygmomanometer. A hollow body containing a fluid therein and having an outer surface that is deformable upon contact;
a pipe having a tip end in fluid communication with the inside of the hollow body;
a flow rate sensor provided in the pipe to measure a flow of a fluid flowing through the pipe;
a contact detection unit that detects the contact based on a measurement result by the flow rate sensor;
It is equipped with
The fluid device further comprises a contact speed estimator that estimates a contact speed at the contact based on a signal waveform measured by the flow sensor. A hollow body containing a fluid therein and having an outer surface that is deformable upon contact;
a pipe having a tip end in fluid communication with the inside of the hollow body;
a flow rate sensor provided in the pipe to measure a flow of a fluid flowing through the pipe;
a contact detection unit that detects the contact based on a measurement result by the flow rate sensor;
It is equipped with
A plurality of pipes are connected to the hollow body at different positions,
The flow rate sensor is provided in each of the plurality of pipes,
The touch device further includes a touch position estimation unit that estimates a touch position of the touch,
The contact position estimating unit estimates the contact position based on a time difference between peaks when the contact is detected in each of a plurality of signal waveforms measured by the plurality of flow sensors. The contact detection unit detects the contact when a differential value of the flow rate measured by the flow rate sensor exceeds a predetermined threshold value.
The fluid device according to any one of claims 1 to 4 . a pump connected to a base end of the pipe and configured to supply the fluid to the inside of the hollow body through the pipe;
a valve provided in the pipe on the opposite side of the hollow body with respect to the flow rate sensor and configured to open and close a flow path defined in the pipe;
The hollow body is configured to be operable by the fluid supplied thereto.
The fluid device according to any one of claims 1 to 5 . The touch panel further includes a contact force estimation unit that estimates a contact force at 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 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 . Further comprising a pressure sensor for measuring a pressure of the fluid inside the hollow body or in the pipe;
the contact force estimation function further includes, as one of the variables, a pressure of the fluid measured by the pressure sensor;
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 . The touch sensor further includes a contact shape estimation unit that estimates a contact shape of the touch,
the contact shape estimation unit estimates the contact shape based on a signal waveform measured by the flow rate sensor;
A fluid device according to any one of claims 1 to 8 . In a pipe fluidly connected to a hollow body having a fluid contained therein and an outer surface configured to be deformable by contact, a flow rate of the fluid when the fluid flows is measured by a flow rate sensor, wherein a first space is defined inside the pipe on the opposite side of the hollow body from the flow rate sensor, the first space being a closed space except for a portion communicating with the flow rate sensor, and a second space is defined inside the hollow body, the second space being a closed space except for a portion communicating with the pipe,
A contact detection method for a fluid device, comprising: detecting contact of the hollow body based on a measured flow rate of the fluid. A flow rate of a fluid flowing through a pipe fluidly connected to a hollow body having a fluid contained therein and an outer surface configured to be deformable by contact, the hollow body constituting a cuff that is wrapped around a part of a subject to be subjected to blood pressure measurement in a cuff-type blood pressure monitor,
A contact detection method for a fluid device, comprising: detecting contact of the hollow body based on a measured flow rate of the fluid. A flow rate of a fluid is measured in a pipe fluidly connected to a hollow body having an outer surface that is deformable by contact with the hollow body,
detecting contact of the hollow body based on the measured flow rate of the fluid;
A contact detection method for a fluid device, comprising estimating a contact speed at the contact based on a signal waveform of the measured flow rate of the fluid. In a pipe fluidly connected to a hollow body having a fluid contained therein and an outer surface configured to be deformable by contact, a flow rate of the fluid when the fluid flows is measured by a flow rate sensor, wherein a plurality of pipes are connected to the hollow body at a plurality of different positions, and the flow rate sensor is provided in each of the plurality of pipes;
detecting contact of the hollow body based on the measured flow rate of the fluid;
A contact detection method for a fluid device, comprising: estimating a contact position based on a time difference between peaks when the contact is detected in each of a plurality of signal waveforms measured by a plurality of the flow sensors.

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