阅读说明：本技术 基于惯性测量单元的呼吸深度与呼吸频率测量装置和方法 (Respiration depth and respiration frequency measuring device and method based on inertia measuring unit ) 是由 方续东 邓武彬 方子艳 吴俊侠 高博楠 孙昊 吴晨 赵立波 田边 王淞立 朱楠 于 2021-09-08 设计创作，主要内容包括：本发明公开了一种基于惯性测量单元的呼吸深度与呼吸频率测量装置和方法,包括用于提供相对参考系的外壳、作为胸部呼吸深度与呼吸频率测量装置的内壳以及第一、第二惯性测量单元。首先通过内外壳以及弹簧连接,为胸部的运动提供了相对参考,再次采用相同的惯性测量单元以及相同的加速度信号处理算法,得到人体呼吸深度与呼吸频率,使得本装置可以避免测量呼吸时由于人体运动产生的干扰,从而获得了一种可实现人体呼吸深度与呼吸频率实时高精度测量的装备和方法,解决了目前呼吸频率监测缺乏实时性且精度受人体运动状态影响较大,而呼吸深度缺乏测量装备和方法的问题。(The invention discloses a respiratory depth and respiratory frequency measuring device and method based on an inertial measurement unit. The device comprises an inner shell, an outer shell, a spring, a measuring device and a measuring device, wherein the inner shell, the outer shell and the spring are connected to provide relative reference for chest movement, the same inertia measuring unit and the same acceleration signal processing algorithm are adopted again to obtain the breathing depth and the breathing frequency of a human body, so that the device can avoid interference caused by the movement of the human body when breathing is measured, equipment and a method capable of realizing real-time high-precision measurement of the breathing depth and the breathing frequency of the human body are obtained, and the problems that the existing breathing frequency monitoring is lack of real-time performance, the precision is greatly influenced by the movement state of the human body, and the breathing depth is lack of the measuring equipment and the method are solved.)

1. The device for measuring the breathing depth and the breathing frequency based on the inertial measurement unit is characterized by comprising an outer shell (11) and an inner shell (12), wherein a first inertial measurement unit (1) is installed in the outer shell (11), and a second inertial measurement unit (2) is installed in the inner shell (12); the first inertia measurement unit (1) and the second inertia measurement unit (2) are arranged oppositely; an inserting rod (15) is fixed on the outer shell (11), an inserting cylinder (16) is fixed on the inner shell (12), one end of the inserting rod (15) extends into the inserting cylinder (16), and a spring (13) is sleeved outside a combined piece formed by the inserting cylinder (16) and the inserting rod (15); the first inertia measurement unit (1) and the second inertia measurement unit (2) are completely the same;

the outer shell (11) and the inner shell (12) are both connected with waistbands, and the waistbands are connected through buckles.

2. The apparatus for measuring respiration depth and respiration frequency based on inertial measurement unit according to claim 1, wherein the first inertial measurement unit (1) and the second inertial measurement unit (2) are installed with wireless transceiver module.

3. The apparatus for measuring the breathing depth and breathing frequency based on the inertial measurement unit of claim 1, wherein the outer shell (11) and the inner shell (12) are made of rigid plastic.

4. The apparatus for measuring the breathing depth and breathing frequency based on the inertial measurement unit according to claim 1 or 3, wherein the surface of the inner shell (12) contacting the human body is coated with silica gel.

5. The inertial measurement unit-based breath depth and breath frequency measurement device according to claim 1, wherein the elastic modulus of the belt attached to the housing (11) is not less than 1 GPa.

6. The inertial measurement unit-based breath depth and frequency measurement device according to claim 1, wherein the waist belt attached to the inner shell (12) is made of a material having elasticity.

7. The method for measuring the breathing depth and the breathing frequency of the high-precision breathing depth and breathing frequency measuring device according to claim 1, comprising the following steps:

s1, calculating specific force data and angular velocity data acquired by the first inertial measurement unit and the second inertial measurement unit to obtain a first acceleration and a second acceleration;

s2, integrating the first acceleration and the second acceleration, and then performing trend term removing processing to obtain a first initial velocity of the first inertia measurement unit and a second initial velocity of the second inertia measurement unit;

s3, performing integration processing on the first initial speed and the second initial speed to obtain a first original displacement signal and a second original displacement signal;

s4, removing trend terms of the first original displacement signal and the second original displacement signal to obtain a first displacement signal and a second displacement signal which can be used;

s5, subtracting the available first displacement signal and the second displacement signal to accurately obtain the breathing depth; and peak processing is carried out on the breathing depth, image extreme points in the depth data are found, and the breathing frequency per minute can be accurately obtained by calculating the number of the extreme points in each minute.

8. The measurement method according to claim 7, wherein after the breathing depth and the breathing frequency per minute are obtained, the obtained breathing depth and the breathing frequency are compared with the recorded breathing depth and the breathing frequency in a calm state for analysis, so that the monitoring and the evaluation of the human body movement form and the physiological health state can be realized.

Technical Field

The invention belongs to the technical field of wearable monitoring of human body breathing depth and breathing frequency, and particularly relates to a high-precision measuring device of breathing depth and breathing frequency based on an inertia measuring unit.

Background

The main manifestations of the human respiratory signal are the respiratory depth and respiratory frequency. Wearable monitoring equipment for human respiratory rate develops rapidly in recent years, and various portable monitoring equipment for respiratory rate is available at present. The extraction method of the respiratory frequency is divided into non-contact measurement and contact measurement. The non-contact measurement comprises methods such as ultrasonic waves and radars, the respiratory depth and respiratory frequency monitoring with high precision can be realized, but the method can only be used under the condition that a person to be measured is static. The contact measurement uses various methods such as a carbon dioxide sensor, a temperature sensor, respiration induction volume marking, an electrocardiogram derivation method and the like, and can realize accurate measurement of the respiratory rate, but the measurement methods lack real-time performance and cannot measure the respiratory depth. The measurement mode using the acceleration sensor and the inertia measurement unit can realize real-time monitoring of the breathing depth and the breathing frequency, but the monitoring can only be used in a static state, and once a person to be measured moves, a larger error can be brought, and the accuracy is seriously influenced. From the above analysis, the measurement of the breathing rate is greatly influenced by the motion state of the human body and the measurement environment at present, and the measurement of the breathing depth lacks the measurement equipment and method.

In order to solve the problems, the patent provides a device and a measuring method, which can realize high-precision real-time measurement and can realize monitoring of the breathing depth and the breathing frequency under a large-amplitude motion state.

Disclosure of Invention

The invention aims to realize real-time high-precision measurement of the breathing depth and the breathing frequency of a human body and solve the problems that the existing breathing frequency measurement lacks real-time performance, the error is large in a motion state, and breathing depth measurement equipment and a method are lacked. The device and the method for monitoring the breathing depth and the breathing frequency in real time and high precision are realized, and the device and the method are particularly suitable for providing reliable real-time breathing depth and breathing frequency measurement under the state of human body large-amplitude motion.

In order to achieve the purpose, the respiration depth and respiration frequency measuring device based on the inertia measuring unit comprises an outer shell and an inner shell, wherein a first inertia measuring unit is installed in the outer shell, and a second inertia measuring unit is installed in the inner shell; the first inertia measurement unit and the second inertia measurement unit are arranged oppositely; an inserting rod is fixed on the outer shell, an inserting cylinder is fixed on the inner shell, one end of the inserting rod extends into the inserting cylinder, and a spring is sleeved outside a combined piece formed by the inserting cylinder and the inserting rod; the first inertia measurement unit and the second inertia measurement unit are completely the same; the outer shell and the inner shell are both connected with waistbands, and the waistbands are connected through buckles.

Furthermore, the first inertia measurement unit and the second inertia measurement unit are both provided with wireless transceiving modules.

Furthermore, the outer shell and the inner shell are made of hard plastics.

Furthermore, one surface of the inner shell, which is in contact with a human body, is coated with silica gel.

Furthermore, the elastic modulus of the waistband connected to the shell is not lower than 1 GPa.

Furthermore, the waistband connected with the inner shell is made of elastic materials.

The method for measuring the breathing depth and the breathing frequency based on the breathing depth and breathing frequency high-precision measuring device comprises the following steps:

s1, resolving data acquired by the first inertia measurement unit and the second inertia measurement unit to obtain a first acceleration and a second acceleration;

s2, after integrating the first acceleration and the second acceleration obtained by the first inertia measurement unit and the second inertia measurement unit, removing a trend term to obtain a first initial velocity and a second initial velocity;

s3, performing integration processing on the first initial speed and the second initial speed to obtain a first original displacement signal and a second original displacement signal;

s4, removing trend terms of the first original displacement signal and the second original displacement signal to obtain a first displacement signal and a second displacement signal which can be used;

s5, subtracting the available first displacement signal and the second displacement signal to accurately obtain the breathing depth; and peak processing is carried out on the breathing depth, image extreme points in the depth data are found, and the breathing frequency per minute can be accurately obtained by calculating the number of the extreme points in each minute.

Furthermore, after the breathing depth and the breathing frequency per minute are obtained, the obtained breathing depth and breathing frequency are compared with the recorded breathing depth and breathing frequency in a calm state for analysis, and the monitoring and evaluation of the human body movement form and the physiological health state can be realized.

Compared with the prior art, the invention has at least the following beneficial technical effects:

the device is provided with a first inertia measuring unit and a second inertia measuring unit, wherein the first inertia measuring unit positioned on the outer shell can provide a reference for the second inertia measuring unit positioned on the inner shell, and the data output by the second inertia measuring unit and the first inertia measuring unit are only caused by chest displacement when a human body breathes due to the fact that the same modules and the same data processing mode are adopted, so that the problem of motion interference caused by the change of the posture of the human body when an acceleration sensor is used for measuring the breathing depth and the breathing frequency is avoided in principle, and the breathing depth and the breathing frequency of a person to be measured can be measured with high precision even when the person to be measured is in a violent motion state.

During the measurement, the spring functions as:

1) the presence of the springs provides support for the housing portion and, due to the compressed state between the springs, provides support for the housing during breathing, preventing the housing from changing position relative to the body during movement.

2) The presence of the spring provides a thrust for the movement of the inner shell, which, when exhaling, reduces the profile of the chest, under the action of the spring,

the inner shell can move against the chest of the human body.

Furthermore, data are output to a mobile phone or other terminals in real time, and the data output of the first inertia measurement unit and the second inertia measurement unit has no hysteresis, so that the device can realize long-time respiration monitoring of a real-time motion state, discover abnormal respiration conditions in time, does not need to consider human motion, and has high precision and stable performance.

The method adopts the completely same sensor module and data processing part to perform difference processing on the obtained displacement signal, and the breathing depth and the breathing frequency of the person to be measured can be measured. A device for providing a relative reference for the movement of the chest during the movement of the human body is provided.

The outer shell, first waistband, the second waistband, the fifth waistband, sixth waistband and buckle constitute the outer loop, because the subassembly that constitutes the outer loop is all not stretchable, or stretch very little when the human body breathes, so the outer loop that its constitutes does not take place deformation on the whole, and because the existence of spring, can prop up the outer loop, make the outer loop keep the state of tightening always, consequently can make the shell on the outer loop and first inertia measuring unit part keep fixed, can guarantee for human thorax simultaneously that the data that first inertia measuring unit in the shell exported only contains human motion, can provide an absolute reference for second inertia measuring unit.

Furthermore, the inner shell, the third waistband, the fourth waistband, the fifth waistband, the sixth waistband and the inner ring formed by the buckle, the third waistband and the fourth waistband are made of stretchable materials, so that the inner shell can move along with the movement of the chest when a human body breathes, and data measured by the second inertia measurement unit fixed in the inner shell reflects the movement of the human body and the movement caused by the chest breathing.

According to the method, the data of the first inertial measurement unit and the data of the second inertial measurement unit are subjected to difference processing, and then the signal caused by breathing only can be obtained. Therefore, the device can inhibit the interference caused by the change of the posture or the motion of the human body and accurately obtain the breathing depth and the breathing frequency.

The device can acquire the breathing depth and the breathing frequency of a human body in real time, measure the breathing depth and the breathing frequency with high precision, has portability and real-time performance, and can effectively predict the health condition of a tested person according to the result and effectively early warn sudden diseases such as acute respiratory failure and the like simultaneously due to the real-time performance of the device.

Drawings

FIG. 1 is a schematic view of the housing construction;

FIG. 2 is a schematic view of an inner shell structure;

FIG. 3 is a schematic view of the inner and outer housings and spring assembly;

FIG. 4a is an assembled front view of the inner and outer housings and the spring;

FIG. 4b is a left side view of the inner and outer housings and spring assembly;

FIG. 4c is a top view of the inner and outer housings and spring assembly;

FIG. 5 is a schematic view of the entire apparatus;

FIG. 6 is a flowchart of a calculation of depth of breath and frequency of breath;

in the drawings: 1. the measuring device comprises a first inertia measuring unit, a second inertia measuring unit, a first waistband, a second waistband, a third waistband, a fourth waistband, a fifth waistband, a sixth waistband, a first inertia measuring unit fixing hole, a second belt, a third belt, a second belt, a third belt, a fourth belt, a.

Detailed Description

In order to make the objects and technical solutions of the present invention clearer and easier to understand. The present invention will be described in further detail with reference to the following drawings and examples, wherein the specific examples are provided for illustrative purposes only and are not intended to limit the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified. In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 5, an acceleration sensor-based apparatus for measuring depth of breath and respiratory rate includes a first inertial measurement unit 1, a second inertial measurement unit 2, a first waistband 3, a second waistband 4, a third waistband 5, a fourth waistband 6, a fifth waistband 7, a sixth waistband 8, an outer shell 11, an inner shell 12, a spring 13, and a buckle 14.

Referring to fig. 1 and 3, the housing 11 includes a first panel 18, a first fixing block 19 is fixed on an inner side of the first panel 18, a first fixing hole 9 is formed in the first fixing block 19, housing connecting portions 17 extend outward from four corners of the first panel 18, the housing connecting portions are connected to a first end of an insertion rod 15, and a second end of the insertion rod 15 is inserted into an insertion tube 16.

Referring to fig. 2, the inner shell 10 includes a second panel 20, a second fixing block 21 is fixed on an inner side of the second panel 20, a second fixing hole 10 is formed in the second fixing block 21, inner shell connecting portions 22 extend outward from four corners of the second panel 20, and the insert cylinder 16 is fixed on the inner shell connecting portions 22. The combination formed by the plunger 15 and the plunger 16 is sheathed with a spring 13.

Referring to fig. 4a, 4b and 4c, the first inertial measurement unit 1 is placed inside the first inertial measurement unit fixing hole 9 and fixed as a single body; the second inertia measurement unit 2 is placed inside the second inertia measurement unit fixing hole 10 and fixed integrally with the inner case 12. The data of the first inertia measurement unit and the second inertia measurement unit are exported to the mobile phone by a wireless module or a wired module.

The inner shell and the outer shell are matched through an inserted rod 15, an inserted cylinder 16 and a spring 13 and can move along the axial direction of the inserted cylinder; the plunger 15 is engaged with the plunger 16, and the inner housing is movable in the axial direction of the plunger 15. The first ends of the first waistband 3 and the second waistband 4 are respectively connected with a through hole arranged on the shell connecting part 17; the third waist belt 5 and the fourth waist belt 6 are respectively connected with through holes arranged on the connecting part 22 of the inner shell; the first end of the fifth waistband 7 is connected with the second ends of the first waistband 3 and the third waistband 5, and the first end of the sixth waistband 8 is connected with the second ends of the second waistband 4 and the fourth waistband 6; the second ends of the fifth waistband 7 and the sixth waistband 8 are respectively connected with the two ends of the buckle 14.

In the embodiment of the invention, the first inertial measurement unit 1 and the second inertial measurement unit 2 adopt the same inertial measurement unit, such as JY 901. According to the invention, the inertial measurement unit is used for measuring the breathing depth and the breathing frequency, JY901 is cheap in price and stable in performance, and the portability of the device is increased as data output adopts wireless output. Meanwhile, the first inertial measurement unit and the second inertial measurement unit adopt the same sensor to ensure the consistency of the output of the two sensors under the same condition to the maximum extent.

As shown in fig. 1, in the embodiment of the present invention, the material of the housing 11 is hard plastic. The hard plastic ensures that the shell part is not deformed or is less deformed, and the integral measurement precision of the device is improved.

As shown in figure 2, the inner shell 12 is made of hard plastic in the embodiment of the invention, the inner shell plays a role in supporting and fixing, the chest part can push the inner shell to move during breathing, and the inner shell is ensured not to deform when the two sides of the inner shell are stressed by using the hard plastic, so that the precision of the device is improved. The inner shell is coated with silica gel on the surface contacting with human body, so that the wearing comfort is improved.

In the present embodiment, the elastic modulus of the first and second waist belts 3 and 4 is not less than 1GPa, and the first and second waist belts are made of flexible materials which hardly or hardly deform under tension, such as nylon ropes or steel cables, and are externally covered by cloth. The first non-stretchable waistband is used in the invention, and the second waistband can fix the outer shell and prevent the outer shell from displacing under the condition that a human body breathes.

In the present embodiment, the third and fourth waist bands 5 and 6 are made of a stretch-recoverable material such as rubber band, and are externally covered with a fabric. In the invention, the pushing motion of the inner shell is pushed by the chest cavity of a human body, the restoring motion of the inner shell is pushed by the rubber band and the spring, and meanwhile, the rubber band is soft, stretchable and deformable, so that the wearing comfort of the device is improved.

In the embodiment of the present invention, the fifth belt 7 and the sixth belt 8 are made of flexible materials which hardly deform or deform little under the stretching condition, and the same materials as the first belt and the second belt can firmly fix the device on the measured person, and meanwhile, the fifth belt and the sixth belt are made of non-stretchable materials, but certain margin is left, so that the device can be worn on the body of any person, and the general applicability of the device is increased.

The wearing steps of the device are as follows:

s1: the whole device is assembled according to the connection relation. The installation mode of the inertia measurement unit is as follows: the z-axis direction of the inertial measurement unit is positioned perpendicular to the face plate 18 outward, i.e., perpendicular to the chest outward direction, and the x-axis is positioned in the horizontal direction.

S2: the side of the inner shell 12 of the device, which is coated with silica gel, faces the human body, and the side of the outer shell 10 faces outwards and is worn along the chest.

S3: when the chest strap is worn, the tested person exhales, the buckle of the chest strap is clamped around the chest of the person, the proper tightness is adjusted, the spring is in a pressed state, and the chest strap is guaranteed to be fixed on the chest of the tested person.

S4: the device is started, the first inertia measurement unit and the second inertia measurement unit start to work, and specific force and angular velocity data are recorded.

Because the output of the inertia measuring unit has the influence of temperature drift, self noise and the like under the actual condition, the device adopts the existing mature method for removing the drift noise of the acceleration sensor, such as: the trend item removing processing, and based on the method and the designed device, the invention also provides a method for monitoring the breathing depth and the breathing frequency in real time, which is shown in fig. 6 and comprises the following steps:

the method comprises the following steps: the acceleration signal of the accelerometer in the inertial measurement unit is not only the acceleration from respiration but also the acceleration from gravity and other types of accelerations. As shown in the following formula:

f＝a+(v·w)+R^T·g

matrix form

Transformation of

f: specific force; f. of_x: specific force along the x-axis; f. of_y: specific force along the y-axis; f. of_z: specific force along the z-axis; a ═ v'_xv′_yv′_z]^T: linear acceleration;

v′_x: x-axis linear acceleration; v'_y: linear acceleration of the y-axis; v'_z: x-axis linear acceleration;

v: a linear velocity; v. of_x: linear velocity along the x-axis; v. of_yLinear velocity along the y-axis; v. of_zLinear velocity along the z-axis; r^T: rotating the matrix;

w＝[w_xw_yw_z]^T: is the angular velocity; w is a_x: angular velocity about the x-axis; w is a_y: angular velocity about the y-axis; w is a_z: angular velocity about the z-axis; g ═ 00 g_z]^T: acceleration of gravity; g_z＝-9.81；

Resolving specific force data and angular velocity data acquired by the first inertial measurement unit and the second inertial measurement unit to obtain actual linear acceleration, and taking the acceleration a of the z axis of the first inertial measurement unit_zObtaining a first acceleration a₁(t) taking the z-axis acceleration a of the second inertial measurement unit_zObtaining a second acceleration a₂(t)。

Step two: the obtained first acceleration a₁(t), second acceleration a₂(t) after integral processing, removing trend term processing to obtain a first initial velocity v of the first inertia measurement unit₁(t), a second initial velocity v of the second inertial measurement unit₂(t)。

Step three: v to be obtained₁(t)，v₂And (t) performing integration processing on the signal to obtain an original displacement signal.

Step four: removing trend item from the original displacement signal obtained in the third step, and removing trend item method and stepThe same step two is carried out to obtain a usable displacement signal s₁(t)，s₂(t)。

Step five: will be available s₁(t)，s₂(t) signal differencing s₂(t)-s₁(t) h (t), the depth of breath h (t) is obtained. Meanwhile, peak processing is carried out on the respiration depth data, extreme points of the image in the depth data are found, and the respiration frequency per minute can be obtained by calculating the number of the extreme points per minute.

Step six: and comparing and analyzing the obtained respiratory frequency with the recorded normal respiratory frequency, and performing early warning treatment when an abnormality occurs.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.