Muscle contraction rate detection method based on thin film pressure sensor and magnetic field stimulator

Abstract

The invention relates to a muscle contraction rate detection method based on a thin film pressure sensor and a magnetic field stimulator, and belongs to the technical field of medical detection. The invention discloses a muscle contraction rate detection method based on a thin film pressure sensor. The method comprises the following steps: S1) pressure value conversion; s2) self-gravity measurement; s3) measuring resting muscle force; s4) measuring stimulation muscle force; and S5) calculating the muscle contraction rate. Based on a conversion formula of voltage and resistance of the thin film pressure sensor, according to factual analysis and theoretical derivation, and in combination with actual operation, the self-gravity of the stimulation coil module, a muscle force value in a resting state and a muscle force value in a stimulation state are measured. The influence of the self-gravity of the stimulation coil module and the muscle force value in the resting state on the actual muscle contraction rate is creatively analyzed and eliminated, and the detection precision of the muscle contraction rate is improved.

Description

Technical Field

[0001] The present invention belongs to the field of medical detection technology, and in particular, relates to a muscle contraction rate detection method based on a thin film pressure sensor and a magnetic field stimulator. Background Art

[0002] With the promotion and use of magnetic field stimulators, more and more magnetic field stimulators are used in pelvic floor treatment and muscle shaping; there is a lack of effective detection methods for indicators such as muscle contraction rate. There is no existing literature on the measurement and calculation methods for detecting indicators such as muscle contraction rate in related usage scenarios.

[0003] In addition, there are currently two main ways to measure indicators such as muscle contraction rate:

[0004] 1. Use electromyographic equipment to calculate the muscle contraction rate by detecting the electromyographic signals of the muscles when the magnetic field stimulator is working.

[0005] However, there is a disadvantage in using electromyographic equipment, which is that the electrodes must be in contact with human skin. This makes the detection work cumbersome and complicated when the magnetic field stimulator is used to treat female pelvic floor and buttocks shaping, and will also cause a considerable number of patients to resist and resist.

[0006] Second, use the air bag to fit the muscle. When the magnetic field stimulator is working, the muscle contraction rate is calculated by detecting the value of the air pressure sensor in the air path.

[0007] However, the magnetic field stimulator of this solution requires an additional air injection system, which makes the system bloated. At the same time, the airbag needs to be fitted with the muscle using a strap, and overpressure can easily cause damage to the airbag. Summary of the invention

[0008] In order to solve the technical problems of lack of effective detection methods for indicators such as muscle contraction rate in the prior art and simple and safe measurement products, the present invention provides a muscle contraction rate detection method based on a thin film pressure sensor and a magnetic field stimulator;

[0009] The purpose of the present invention can be achieved through the following technical solutions:

[0010] The muscle contraction rate detection method based on the thin film pressure sensor comprises the following steps:

[0011] S1) Pressure value conversion: Since the thin film pressure sensor is equivalent to a variable resistor, its real-time working resistance will change after being affected by pressure; the conversion relationship between the real-time working resistance and pressure of the thin film pressure sensor is:

[0012]

[0013] Wherein, R is the real-time working resistance of the thin film pressure sensor; F is the pressure on the thin film pressure sensor; K is the conversion coefficient.

[0014] Preferably, the method for measuring the real-time working resistance of the thin film pressure sensor is:

[0015] In the circuit of the magnetic field stimulator, a resistor voltage division method is used to measure and calculate the real-time working resistance of the thin film pressure sensor through the operational circuit of the operational amplifier; the calculation formula is:

[0016]

[0017] Where: V in is a given input voltage; V out is the operating voltage of the thin film pressure sensor, which is measured by the operational amplifier; R is the real-time working resistance of the thin film pressure sensor; R2 is a known resistance.

[0018] Preferably, the real-time working resistance of the thin film pressure sensor is measured by using a Wheatstone bridge method, and the specific steps are as follows:

[0019] The thin film pressure sensor is used as one arm of the bridge, and the other three arms are known resistors.

[0020] Adjust the bridge to reach a balanced state, at which point the output voltage of the bridge is zero.

[0021] The real-time working resistance of the thin film pressure sensor can be calculated by knowing the resistance and the balance condition of the bridge.

[0022] Preferably, the specific value of the conversion coefficient is solved and verified by a calibration experiment. The conversion coefficient (K) is a key parameter. A reasonable and matching calibration experiment is formulated according to the actual application scenario and measurement data; and its accuracy is verified. This method ensures the reliability and accuracy of the measurement results.

[0023] S2) Self-gravity measurement: measure the pressure value of the thin film pressure sensor under the gravity of the stimulation coil module only, that is, the self-gravity of the stimulation coil module; the calculation formula is expressed as:

[0024]

[0025] Where G is the self-weight of the stimulation coil module; R0 is the real-time working resistance of the thin film pressure sensor under the gravity of the stimulation coil module only; K is the conversion coefficient.

[0026] Preferably, a method of using a statistical root mean square value is also included to eliminate the measurement error of the self-gravity of the stimulation coil module, and used as a subsequent calculation standard; the specific method is:

[0027] By repeating the self-gravity measurement of step S2) for multiple times, the data set of the real-time working resistance of the thin film pressure sensor [R0] is obtained, and then the self-gravity data set of the stimulation coil module [G i ]; finally calculate its RMS value;

[0028]

[0029] In the formula, G RMS is the root mean square value of the self-gravity of the stimulation coil module; G i is the self-gravity value of the stimulation coil module; n is the total number of data sets.

[0030] S3) Resting muscle force measurement: when the stimulation coil module is placed on the muscle and not working, the muscle force generated by the muscle, the muscle force at this time interacts with the gravity of the stimulation coil module, causing the pressure of the thin film pressure sensor to change, resulting in the pressure of the thin film pressure sensor no longer being equal to the self-gravity of the stimulation coil module;

[0031] Obtain the real-time working resistance of the thin film pressure sensor in the static measurement at this time, and calculate the pressure of the thin film pressure sensor at this time;

[0032]

[0033] Where Fa is the pressure of the thin film pressure sensor in the static measurement; Ra is the real-time working resistance of the thin film pressure sensor in the static measurement;

[0034] The difference between the self-weight of the stimulation coil module and the pressure of the thin film pressure sensor in the resting measurement is the resting muscle force; its calculation formula is:

[0035] Fs = |Fa-G|;

[0036] Where Fs is the resting muscle force, taking the absolute value of the difference; Fa is the pressure of the thin film pressure sensor in the resting measurement; G is the self-weight of the stimulation coil module.

[0037] Preferably, by repeating the resting muscle strength measurement in step S3) for multiple times, a statistical root mean square value method is used to eliminate the measurement error of the resting muscle strength, and the method is used as a subsequent calculation standard.

[0038] S4) Stimulation muscle force measurement: When the stimulation coil module is placed on the muscle and works, the muscle will perform isometric or isotonic contraction according to the frequency of magnetic field stimulation, causing the pressure of the thin film pressure sensor to change;

[0039] Obtaining the real-time working resistance of the thin film pressure sensor in the stimulation measurement at this time, and calculating the pressure of the thin film pressure sensor at this time;

[0040]

[0041] Where, Fc is the pressure of the thin film pressure sensor in the stimulation measurement; Rc is the real-time working resistance of the thin film pressure sensor in the stimulation measurement;

[0042] The difference between the self-weight of the film pressure sensor and the stimulated measured pressure is the stimulated muscle force; its calculation formula is:

[0043] Fm = |Fc-G|;

[0044] Where, Fm is the stimulation muscle force, taking the absolute value of the difference; Fc is the pressure of the thin film pressure sensor in the stimulation measurement; G is the self-weight of the stimulation coil module.

[0045] Preferably, a statistical root mean square value method is used to eliminate the measurement error of the stimulated muscle force, and is used as a subsequent calculation standard.

[0046] S5) Calculation of muscle contraction rate: The muscle contraction rate is calculated based on the difference between resting muscle strength and stimulated muscle strength; the calculation formula is:

[0047]

[0048] Where P is the muscle contraction rate; Fm is the stimulated muscle force; Fs is the resting muscle force.

[0049] Preferably, the calculation data of the muscle contraction rate is based on the corresponding root mean square value.

[0050] Preferably, the present invention also proposes a magnetic field stimulator based on a thin film pressure sensor, including a thin film pressure sensor working circuit and a stimulation coil module; the thin film pressure sensor working circuit is used to measure the real-time working resistance of the thin film pressure sensor, including a thin film pressure sensor, a known resistor and an operational amplifier; the thin film pressure sensor is connected to the positive phase input terminal of the operational amplifier; the known resistor is respectively connected to the negative phase input terminal and output terminal of the operational amplifier; the stimulation coil module is used to generate a high-intensity changing magnetic field and act on the target muscle group.

[0051] Beneficial effects of the present invention:

[0052] 1. The present invention is based on the conversion formula of the voltage and resistance of the thin film pressure sensor, based on factual analysis and theoretical deduction, and combined with actual operation to measure the self-gravity of the stimulation coil module, the muscle strength value in the resting state, and the muscle strength value in the stimulation state. The invention creatively analyzes and eliminates the influence of the self-gravity of the stimulation coil module and the muscle strength value in the resting state on the actual muscle contraction rate, thereby improving the detection accuracy of the muscle contraction rate.

[0053] 2. Use the resistance voltage division method or Wheatstone bridge method to design the working circuit of the thin film pressure sensor to improve the convenience and accuracy of the real-time resistance measurement of the thin film pressure sensor.

[0054] 3. The magnetic field stimulator with integrated thin film pressure sensor of the present invention is different from the traditional method of measuring muscle strength using airbags and air pressure sensors. It does not require additional air pressure sensors, additional air delivery systems, and there is no risk of airbags bursting due to excessive pressure. Therefore, the solution based on thin film pressure sensors is simpler and easier to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0056] Figure 1 The present invention is a flow chart of a method for detecting muscle contraction rate based on a thin film pressure sensor.

[0057] Figure 2 It is a structural schematic diagram of a magnetic field stimulator based on a thin film pressure sensor of the present invention.

[0058] Figure 3 The present invention is a schematic diagram of the working circuit of the thin film pressure sensor in the magnetic field stimulator based on the thin film pressure sensor. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] See also Figure 1-Figure 3 As shown, the muscle contraction rate detection method based on the thin film pressure sensor and the magnetic field stimulator are both within the scope of protection of the present invention.

[0061] A muscle contraction rate detection method based on a thin film pressure sensor and a magnetic field stimulator include the following steps:

[0062] S1) Pressure value conversion: Since the thin film pressure sensor is equivalent to a variable resistor, its real-time working resistance will change after being affected by pressure; the conversion relationship between the real-time working resistance and pressure of the thin film pressure sensor is:

[0063]

[0064] Wherein, R is the real-time working resistance of the thin film pressure sensor; F is the pressure on the thin film pressure sensor; K is the conversion coefficient.

[0065] Specifically, a thin film pressure sensor is a device that converts pressure into resistance changes, and therefore can be equivalent to a variable resistor that changes with pressure; it is composed of sensitive materials such as carbon paste wrapped in PET material. It is suitable for smooth surfaces, has a repetition rate of ±5% and a nonlinear pressure-resistance relationship. Specifically, the relationship between pressure and resistance value is generally an approximate inverse, rather than a linear relationship.

[0066] It should be noted that the magnetic field stimulator in the present invention can be used in muscle detection and rehabilitation treatment; and the thin film pressure sensor therein can be used to monitor muscle activity in real time. By attaching the sensor to the surface of the skin, the subtle deformation and pressure changes of the muscle under magnetic field stimulation can be detected. These data can be used to evaluate the reactivity and functional status of the muscle, helping doctors and researchers understand the health status of the muscle.

[0067] The stimulation coil module can be used in muscle rehabilitation therapy. It generates a high-intensity changing magnetic field, penetrates fat tissue, and acts on the target muscle group. The magnetic field generates an induced current in the target muscle group, depolarizes the motor neurons, and induces muscle peak contraction. This peak contraction increases muscle strength and tension, which helps muscle rehabilitation.

[0068] Therefore, by integrating the thin film pressure sensor into the magnetic field stimulator, the new magnetic field stimulator can not only be used for muscle rehabilitation treatment, but also can detect and evaluate muscle pressure values, muscle contraction rate and other indicators; it shows its unique advantages and broad application prospects.

[0069] Preferably, the method for measuring the real-time working resistance of the thin film pressure sensor is:

[0070] In the circuit of the magnetic field stimulator, a resistor voltage division method is used to measure and calculate the real-time working resistance of the thin film pressure sensor through the operational circuit of the operational amplifier; the calculation formula is:

[0071]

[0072] Where: V in is a given input voltage; V out is the operating voltage of the thin film pressure sensor, which is measured by the operational amplifier; R is the real-time working resistance of the thin film pressure sensor; R2 is a known resistance.

[0073] Specifically, Figure 1As for the thin film pressure sensor measurement circuit shown in the figure, the resistance voltage division method is adopted. The real-time working resistance R of the thin film pressure sensor and the known resistance R2 form a voltage division circuit; the thin film pressure sensor is connected to the positive input terminal of the operational amplifier 0PA; the known resistance R2 is short-circuited with the negative input terminal and output terminal of 0PA to form a voltage follower. Therefore, for the resistance R of the thin film pressure sensor, its resistance R changes with the pressure. And different types of thin film pressure sensors (different sizes and manufacturing materials, etc.) will have different K values.

[0074] In the specific implementation process, you can choose the high-performance thin film pressure sensor produced by Changzhou Tiance Electronic Technology Co., Ltd., which uses a gridded semiconductor substrate and contains multiple sensing elements inside, which can accurately measure pressure changes. It is usually used in application scenarios that require high precision and high sensitivity, such as industrial automation and medical equipment.

[0075] Preferably, the real-time working resistance of the thin film pressure sensor is measured by using a Wheatstone bridge method, and the specific steps are as follows:

[0076] The thin film pressure sensor is used as one arm of the bridge, and the other three arms are known resistors.

[0077] Adjust the bridge to reach a balanced state, at which point the output voltage of the bridge is zero.

[0078] The real-time working resistance of the thin film pressure sensor can be calculated by knowing the resistance and the balance condition of the bridge.

[0079] In the specific implementation process, you can also choose WIKA's FLC-1000 series thin film pressure sensor produced by WIKA Automation Instrument (Suzhou) Co., Ltd., which adopts a grid-type resistor structure, integrates four resistors inside, and is installed on the diaphragm in the form of a Wheatstone bridge; thus directly calculating the real-time working resistance of the thin film pressure sensor. This design can accurately detect the deformation of the diaphragm under pressure and is suitable for high-precision pressure measurement.

[0080] Preferably, the specific value of the conversion coefficient is solved and verified by a calibration experiment. The conversion coefficient (K) is a key parameter. A reasonable and matching calibration experiment is formulated according to the actual application scenario and measurement data; and its accuracy is verified. This method ensures the reliability and accuracy of the measurement results.

[0081] S2) Self-gravity measurement: measure the pressure value of the thin film pressure sensor under the gravity of the stimulation coil module only, that is, the self-gravity of the stimulation coil module; the calculation formula is expressed as:

[0082]

[0083] Where G is the self-weight of the stimulation coil module; R0 is the real-time working resistance of the thin film pressure sensor under the gravity of the stimulation coil module only; K is the conversion coefficient.

[0084] Specifically, Figure 3 As shown, the present invention integrates a thin film pressure sensor into a magnetic field stimulator to detect muscle pressure. Since the thin film pressure sensor is combined with the stimulation coil module by adhesion or snapping, when the muscle tissue is detected, the thin film pressure sensor is subjected to the gravity from the stimulation coil module. If the muscle contraction rate is to be accurately calculated, it is necessary to eliminate the influence of the gravity of the stimulation coil module on the muscle strength. Therefore, it is necessary to measure the gravity of the stimulation coil module; the specific measurement process is as follows:

[0085] First, place the magnetic field stimulator horizontally on the table and power it on. The thin film pressure sensor can collect data, but the magnetic field stimulation coil does not work.

[0086] The real-time working resistance of the thin film pressure sensor collected when only the gravity of the stimulation coil module is applied;

[0087] The pressure value of the thin film pressure sensor is calculated through the resistance-pressure conversion formula, which is the self-weight of the stimulation coil module.

[0088] Preferably, a method of using a statistical root mean square value is also included to eliminate the measurement error of the self-gravity of the stimulation coil module, and used as a subsequent calculation standard; the specific method is:

[0089] By repeating the self-gravity measurement of step S2) for multiple times, the data set of the real-time working resistance of the thin film pressure sensor [R0] is obtained, and then the self-gravity data set of the stimulation coil module [G i ]; finally calculate its RMS value;

[0090]

[0091] In the formula, G RMS is the root mean square value of the self-gravity of the stimulation coil module; G i is the self-gravity value of the stimulation coil module; n is the total number of data sets.

[0092] Specifically, during the repeated measurement and sampling process, due to the structural layout and material distribution of the stimulation coil module and the thin film pressure sensor in the main structure of the new magnetic field stimulator, the thin film pressure sensor can more accurately measure the pressure by adjusting different placement postures and flattening its surface.

[0093] The root mean square (RMS) is a commonly used statistical indicator used to measure the degree of dispersion of a set of data. It is calculated by first squaring each data value, then finding the average of these square values, and finally taking the square root of the average. It is used as a subsequent calculation standard to further improve measurement accuracy and reliability.

[0094] S3) Resting muscle force measurement: when the stimulation coil module is placed on the muscle and not working, the muscle force generated by the muscle, the muscle force at this time interacts with the gravity of the stimulation coil module, causing the pressure of the thin film pressure sensor to change, resulting in the pressure of the thin film pressure sensor no longer being equal to the self-gravity of the stimulation coil module;

[0095] Obtain the real-time working resistance of the thin film pressure sensor in the static measurement at this time, and calculate the pressure of the thin film pressure sensor at this time;

[0096]

[0097] Where Fa is the pressure of the thin film pressure sensor in the static measurement; Ra is the real-time working resistance of the thin film pressure sensor in the static measurement;

[0098] The difference between the self-weight of the stimulation coil module and the pressure of the thin film pressure sensor in the resting measurement is the resting muscle force; its calculation formula is:

[0099] Fs = |Fa-G|;

[0100] Where Fs is the resting muscle force, taking the absolute value of the difference; Fa is the pressure of the thin film pressure sensor in the resting measurement; G is the self-weight of the stimulation coil module.

[0101] Specifically, before stimulation, resting muscle strength needs to be measured. This step mainly measures the muscle strength generated by the muscle when the stimulation coil acts on the muscle at rest. Usually, resting muscle strength measurement refers to obtaining the muscle strength when the stimulation coil module is combined with the muscle through its own gravity or through a strap before the magnetic field stimulator stimulates. At this time, the magnetic field stimulator does not stimulate, but the stimulation coil module actively or passively exerts pressure on the muscle, thereby generating resting muscle strength in the muscle.

[0102] Therefore, the difference between the self-weight of the stimulation coil module and the pressure of the thin film pressure sensor in the resting measurement is the resting muscle force.

[0103] Preferably, by repeating the resting muscle strength measurement in step S3) for multiple times, a statistical root mean square value method is used to eliminate the measurement error of the resting muscle strength, and the method is used as a subsequent calculation standard.

[0104] Specifically, this step can capture the data of pressure changes through high-frequency sampling to ensure the accuracy and integrity of the data. Statistical methods are used to analyze the data and extract accurate parameters, such as root mean square.

[0105] During the resting measurement process, a suitable time period is selected to collect the real-time working resistance of the thin film pressure sensor at a sampling rate of 60-100Hz, and then the pressure of the thin film pressure sensor in the resting measurement is calculated to form a data set. Finally, the statistical root mean square value method is used to eliminate the measurement error of resting muscle strength and serve as the subsequent calculation standard.

[0106] S4) Stimulation muscle force measurement: When the stimulation coil module is placed on the muscle and works, the muscle will perform isometric or isotonic contraction according to the frequency of magnetic field stimulation, causing the pressure of the thin film pressure sensor to change;

[0107] Obtaining the real-time working resistance of the thin film pressure sensor in the stimulation measurement at this time, and calculating the pressure of the thin film pressure sensor at this time;

[0108]

[0109] Where, Fc is the pressure of the thin film pressure sensor in the stimulation measurement; Rc is the real-time working resistance of the thin film pressure sensor in the stimulation measurement;

[0110] The difference between the self-weight of the film pressure sensor and the stimulated measured pressure is the stimulated muscle force; its calculation formula is:

[0111] Fm = |Fc-G|;

[0112] Where, Fm is the stimulation muscle force, taking the absolute value of the difference; Fc is the pressure of the thin film pressure sensor in the stimulation measurement; G is the self-weight of the stimulation coil module.

[0113] Preferably, a statistical root mean square value method is used to eliminate the measurement error of the stimulated muscle force, and is used as a subsequent calculation standard.

[0114] Specifically, the magnetic field stimulator measures the muscle force generated by the muscle when the stimulation coil module is working. After the stimulation coil starts working, the muscle will perform isometric or isotonic contraction with the frequency of magnetic field stimulation, thereby causing the pressure of the thin film pressure sensor to change.

[0115] Similarly, this step can also capture the data of pressure changes through high-frequency sampling. During the stimulation measurement process, select a suitable time period to collect the real-time working resistance of the thin film pressure sensor at a sampling rate of 60-100Hz and form a data collection. Finally, the statistical root mean square value method is used to eliminate the measurement error of resting muscle strength and serve as the subsequent calculation standard.

[0116] S5) Calculation of muscle contraction rate: The muscle contraction rate is calculated based on the difference between resting muscle strength and stimulated muscle strength; the calculation formula is:

[0117]

[0118] Where P is the muscle contraction rate; Fm is the stimulated muscle force; Fs is the resting muscle force.

[0119] Preferably, the calculation data of the muscle contraction rate is based on the corresponding root mean square value.

[0120] The present invention is based on the conversion formula of the voltage and resistance of the thin film pressure sensor, according to fact analysis and theoretical deduction, and combined with actual operation to measure the self-gravity of the stimulation coil module, the muscle strength value in the resting state, and the muscle strength value in the stimulation state. The invention creatively analyzes and eliminates the influence of the self-gravity of the stimulation coil module and the muscle strength value in the resting state on the actual muscle contraction rate, thereby improving the detection accuracy of the muscle contraction rate.

[0121] See also Figure 2-Figure 3 As shown, the present invention also proposes a magnetic field stimulator based on a thin film pressure sensor, including a thin film pressure sensor working circuit and a stimulation coil module; the thin film pressure sensor working circuit is used to measure the real-time working resistance of the thin film pressure sensor, including a thin film pressure sensor, a known resistor and an operational amplifier; the thin film pressure sensor is connected to the positive phase input terminal of the operational amplifier; the known resistor is respectively connected to the negative phase input terminal and the output terminal of the operational amplifier; the stimulation coil module is used to generate a high-intensity changing magnetic field and act on the target muscle group.

[0122] The new magnetic field stimulator is different from the traditional method of measuring muscle strength using air bags and air pressure sensors. It does not require additional air pressure sensors, does not require additional air supply systems, and does not have the risk of air bags bursting due to excessive pressure. Therefore, the solution of using thin film pressure sensors is simpler and easier to implement. Through the above implementation process and measurement method, the new magnetic field stimulator is applied in muscle medical testing to provide more accurate and reliable measurement results.

[0123] In several embodiments provided in this application, it should be understood that the disclosed calculation method can be implemented in other ways.

[0124] If the calculation method is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, read-only memory), random access memory (RAM, random access memory), disk or optical disk and other media that can store program code.

[0125] In the description of the specification, the description with reference to the terms "specifically", "example", "specific implementation process", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0126] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A muscle contraction rate detection method based on a thin film pressure sensor, characterized in that: The following steps are involved: S1) Pressure value conversion: Since the thin film pressure sensor is equivalent to a variable resistor, its real-time working resistance will change after being affected by pressure; the conversion relationship between the real-time working resistance and pressure of the thin film pressure sensor is: In the formula, R is the real-time working resistance of the thin film pressure sensor; F is the pressure on the thin film pressure sensor; K is the conversion coefficient; S2) Self-gravity measurement: measure the pressure value of the thin film pressure sensor under the gravity of the stimulation coil module only, that is, the self-gravity of the stimulation coil module; the calculation formula is expressed as: In the formula, G To stimulate the self-gravity of the coil module; R 0 is the real-time working resistance of the thin film pressure sensor under the gravity of the stimulation coil module only; K is the conversion coefficient; S3) Resting muscle strength measurement: The muscle strength generated by the muscle when the stimulation coil module is placed on the muscle and not working; Obtain the real-time working resistance of the thin film pressure sensor in the static measurement at this time, and calculate the pressure of the thin film pressure sensor at this time; In the formula, F a is the pressure of the thin film pressure sensor in the static measurement; R a is the real-time working resistance of the thin film pressure sensor in static measurement; The difference between the self-weight of the stimulation coil module and the pressure of the thin film pressure sensor in the resting measurement is the resting muscle force; The calculation formula is: Fs = |Fa-G|; Where, Fs is the resting muscle force, taking the absolute value of the difference; Fa is the pressure of the thin film pressure sensor in the resting measurement; G is the self-weight of the stimulation coil module; S4) Stimulation muscle force measurement: When the stimulation coil module is placed on the muscle and works, the muscle will perform isometric or isotonic contraction according to the frequency of magnetic field stimulation, causing the pressure of the thin film pressure sensor to change; Obtaining the real-time working resistance of the thin film pressure sensor in the stimulation measurement at this time, and calculating the pressure of the thin film pressure sensor at this time; Where, FC is the pressure of the thin film pressure sensor in the stimulus measurement; Rc is the real-time working resistance of the thin film pressure sensor in the stimulus measurement; The difference between the self-weight of the film pressure sensor and the stimulated measured pressure is the stimulated muscle force; its calculation formula is: Fm = |Fc-G|; Where, Fm is the stimulated muscle force, taking the absolute value of the difference; Fc is the pressure of the thin film pressure sensor in the stimulation measurement; G is the self-weight of the stimulation coil module; S5) Calculation of muscle contraction rate: The muscle contraction rate is calculated based on the difference between resting muscle strength and stimulated muscle strength; the calculation formula is: Where P is the muscle contraction rate; Fm is the stimulated muscle force; Fs is the resting muscle force.

2. The muscle contraction rate detection method based on a thin film pressure sensor according to claim 1 is characterized in that: The method for measuring the real-time working resistance of the thin film pressure sensor is: In the circuit of the magnetic field stimulator, a resistor voltage division method is used to measure and calculate the real-time working resistance of the thin film pressure sensor through the operational circuit of the operational amplifier; the calculation formula is: Where: V in is a given input voltage; V out is the operating voltage of the thin film pressure sensor, which is measured by the operational amplifier; R is the real-time working resistance of the thin film pressure sensor; R2 is a known resistance.

3. The muscle contraction rate detection method based on a thin film pressure sensor according to claim 1 is characterized in that: The method for measuring the real-time working resistance of the thin film pressure sensor is to use the Wheatstone bridge method, and the specific steps are as follows: The thin film pressure sensor is used as one arm of the bridge, and the other three arms are known resistors; Adjust the bridge to reach a balanced state, at which point the output voltage of the bridge is zero; The real-time working resistance of the thin film pressure sensor can be calculated by knowing the resistance and the balance condition of the bridge.

4. The muscle contraction rate detection method based on a thin film pressure sensor according to claim 1 is characterized in that: The specific value of the conversion coefficient is solved and verified through calibration experiments.

5. The muscle contraction rate detection method based on a thin film pressure sensor according to claim 1 is characterized in that: It also includes the use of a statistical root mean square value method to eliminate the measurement error of the self-gravity of the stimulation coil module and use it as a subsequent calculation standard; the specific method is: By repeating the self-gravity measurement of step S2) for multiple times, the data set of the real-time working resistance of the thin film pressure sensor [R0] is obtained, and then the self-gravity data set of the stimulation coil module [G i ]; finally calculate its RMS value; In the formula, G RMS is the root mean square value of the self-gravity of the stimulation coil module; G i is the self-gravity value of the stimulation coil module; n is the total number of data sets.

6. The muscle contraction rate detection method based on a thin film pressure sensor according to claim 1 is characterized in that: By repeating the resting muscle strength measurement in step S3) for multiple times, the measurement error of the resting muscle strength is eliminated by using the statistical root mean square value method, and it is used as the subsequent calculation standard.

7. The muscle contraction rate detection method based on a thin film pressure sensor according to claim 1 is characterized in that: By repeating the stimulation muscle force measurement in step S4) for multiple times, the measurement error of the stimulation muscle force is eliminated by using the statistical root mean square value method, and is used as the subsequent calculation standard.

8. The muscle contraction rate detection method based on a thin film pressure sensor according to any one of claims 5 to 7, characterized in that: The calculated data of the muscle contraction rate is based on the corresponding root mean square value.

9. A magnetic field stimulator based on a thin film pressure sensor, characterized in that: It includes a thin film pressure sensor working circuit and a stimulation coil module; The thin film pressure sensor working circuit is used to measure the real-time working resistance of the thin film pressure sensor, and includes the thin film pressure sensor, a known resistor and an operational amplifier; The thin film pressure sensor is connected to the positive phase input terminal of the operational amplifier; the known resistor is connected to the negative phase input terminal and the output terminal of the operational amplifier respectively; The stimulation coil module is used to generate a high-intensity changing magnetic field and act on the target muscle groups.

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