A method and system for feces hardness assessment for an assisted defecation system

Abstract

The present application relates to the technical field of biomedical engineering, and particularly relates to a feces hardness evaluation method and system for assisting defecation system, which comprises the following steps: controlling a mechanical arm to insert a probe integrated with a sensor into a rectum; after the probe passes through an anal sphincter, measuring an idling energy consumption; advancing by a unit distance to measure a rectal wall friction energy consumption; continuing to advance to contact feces to measure a total energy consumption; calculating a first feces hardness index based on the idling energy consumption, the friction energy consumption and the total energy consumption, then synchronously calculating a second feces hardness index by using composition data obtained by bioelectrical impedance measurement electrodes, and calculating a third feces hardness index by using pressure data obtained by a pressure sensor, and weighting and fusing the three indexes into a feces comprehensive hardness index. The present application realizes real-time and accurate feces hardness evaluation in the anus and intestines by multi-modal sensing and data fusion, and provides a reliable basis for personalized adjustment of parameter adjustment of the assisting defecation system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomedical engineering, in particular to a feces hardness evaluation method and system for an assisted defecation system. BACKGROUND

[0002] Defecation difficulty (such as constipation) is a common health problem that plagues many people, especially the elderly, bedridden patients, and postoperative patients. Long-term defecation difficulty not only reduces the quality of life, but also can cause hemorrhoids, anal fissures, and even serious complications such as cardiovascular and cerebrovascular accidents. In order to help these patients, various assisted defecation systems have emerged, which usually soften, break up, or push the feces through physical means (such as water flow flushing, air flow boosting, mechanical stirring, etc.) to assist in its discharge.

[0003] However, there is a significant common defect in the clinical application of existing assisted defecation systems: the lack of real-time and accurate perception of the physical properties of feces. The hardness of feces is a key physical parameter that determines the difficulty of its discharge. Currently, the working parameters of the system (such as water flow pressure) are mostly preset by medical personnel based on experience or roughly adjusted by the patient's subjective feeling, which can lead to the following problems: 1) low efficiency: for feces with low hardness, if the assistance force is too strong, it may cause resource waste, patient discomfort, and even rectal mucosa damage; for hard and dry feces, if the assistance force is insufficient, it cannot effectively solve the problem, resulting in repeated and ineffective defecation process; 2) safety risk: unable to real-time perceive the changes in feces state, there may be a risk of damaging the intestinal tissue during operation; 3) lack of individualization: unable to dynamically adjust the treatment plan according to the real-time changes in the feces of each patient, it is difficult to achieve truly personalized and adaptive medical care.

[0004] In the prior art, the evaluation of feces hardness is mostly limited to in vitro methods, such as the Bristol Stool Chart, which is a subjective classification method based on visual observation and cannot be used for real-time in vivo evaluation. Therefore, there is an urgent need in the art for a technology that can evaluate the hardness of feces in real time, online, and quantitatively after the assisted defecation probe enters the rectum, thereby providing a reliable control basis for the assisted defecation devices or systems mentioned in the publication numbers CN116650063A and CN116831698B, and achieving safe, efficient, and comfortable personalized defecation assistance. SUMMARY

[0005] The present application provides a feces hardness evaluation method and system for an assisted defecation system, which aims to solve the technical problems raised in the background.

[0006] In a first aspect, the present application provides a feces hardness evaluation method for an assisted defecation system, comprising:

[0007] Step S1: control the mechanical arm to insert the probe into the rectum through the anus, the probe front end coaxially integrated sensor;

[0008] Step S2: when the probe just passes through the anal sphincter and has not yet contacted the feces, the mechanical arm stops axial feeding and rotates the probe by the motor drive for a time , calculate the idling energy consumption ;

[0009] Step S3: the mechanical arm continues to advance axially by a unit distance , the probe still rotates at the same speed in the same time in the feces-free area , calculate the unit distance rectal wall friction energy consumption ;

[0010] Step S4: the mechanical arm continues to advance axially by a distance until the sensor detects contact with the feces, the mechanical arm immediately stops axial feeding and keeps the probe in contact with the feces;

[0011] Step S5: drive the probe to rotate again at the same speed for the same time , calculate the total energy consumption after contacting the feces ;

[0012] Step S6: calculate the first feces hardness index = - - , wherein is the energy-hardness calibration coefficient.

[0013] Further, in step S1, the sensor includes a pressure sensor, a bioelectrical impedance measurement electrode.

[0014] Further, in step S2, the idling energy consumption is calculated by the formula:

[0015] ;

[0016] wherein, is the bus voltage of the motor, is the motor current of the step, is the probe rotation time;

[0017] In step S5, the total energy consumption after contacting the feces is calculated by the formula:

[0018] ;

[0019] wherein, is the motor current of the step.

[0020] Further, the unit distance rectal wall friction energy consumption in step S3 is calculated as follows: The calculation formula is as follows:

[0021]

[0022] Wherein, I is the motor current of this step.

[0023] Further, the sensor detects the contact with feces in step S4, specifically: when the pressure sensor detects that the pressure value suddenly increases to the preset pressure threshold value, and the bioelectrical impedance phase angle sampled by the bioelectrical impedance measurement electrode changes to the preset phase angle angle, it is determined that the probe has contacted with feces.

[0024] Further, the energy-hardness calibration coefficient in step S6 is obtained by the following steps:

[0025] Step S601: Prepare a plurality of standard fecal simulants with different known hardness values H;

[0026] Step S602: Place the standard fecal simulants in the rectal simulator, control the mechanical arm and the probe, and repeatedly execute the steps S1 to S5, measure and record the corresponding idle energy consumption E, unit distance rectal wall friction energy consumption F, total energy consumption after contacting with feces T, and pushing distance D of each standard fecal simulator.

[0027] Step S603: For each standard fecal simulator, calculate its net energy consumption N.

[0028] Step S604: Perform linear regression analysis with the net energy consumption N as the independent variable and the known hardness value H as the dependent variable, and fit a linear equation of N.

[0029] Step S605: The slope K of the linear equation is determined as the energy-hardness calibration coefficient K. .

[0030] Further, when the contact with feces is detected in step S4, the bioelectrical impedance measurement electrode synchronously collects double-frequency bioelectrical impedance data, and the extracellular fluid ratio V and the phase angle φ are fitted by using the Cole-Cole model, and the second fecal hardness index H2 is calculated. Wherein, ​​​​​​​​​​​​​​These are the baseline values ​​for the proportion of extracellular fluid and the phase angle in the stool during stool softening. This is the electrical impedance-hardness calibration coefficient.

[0031] Furthermore, after step S6, the method further includes recording the pressure value collected by the pressure sensor after the probe stops rotating. The robotic arm continues to advance axially a unit distance. Record pressure values Calculate the third fecal hardness index ,in This is the pressure-hardness calibration factor.

[0032] Furthermore, step S6 further includes, […]. , , The weighted average of the combined fecal hardness index ,Will The signal is sent to the defecation assistance system to adjust the water flow pulse intensity, airflow boost frequency, and probe rotation speed in real time, thereby achieving personalized defecation assistance.

[0033] Secondly, the present invention provides a fecal hardness assessment system for an auxiliary defecation system, for implementing the aforementioned fecal hardness assessment method for an auxiliary defecation system, comprising:

[0034] robotic arm;

[0035] A probe, operably connected to the robotic arm 1, and configured for transanal insertion into the rectum;

[0036] An electric motor, which is connected to the probe drive, is used to drive the probe to rotate;

[0037] The sensor, coaxially integrated at the front end of the probe, is used to detect the contact between the probe and feces, and specifically includes a pressure sensor and a bioelectrical impedance measurement electrode.

[0038] A control unit, which is communicatively connected to the robotic arm, the sensor, and the motor;

[0039] The first fecal hardness index calculation unit in the control unit calculates the first fecal hardness index based on the energy consumption of the motor during the process of the probe being fed into the rectum and coming into contact with the feces.

[0040] The second fecal hardness index calculation unit, located within the control unit, calculates the second fecal hardness index based on the dual-frequency bioelectrical impedance data of the feces measured by the bioelectrical impedance measuring electrode.

[0041] A third stool hardness index calculation unit, the third stool hardness index calculation unit in the control unit calculates a third stool hardness index according to the pressure data detected by the pressure sensor;

[0042] A stool comprehensive hardness index calculation unit, the stool comprehensive hardness index calculation unit in the control unit calculates a comprehensive hardness index of the stool according to the first stool hardness index, the second stool hardness index and the third stool hardness index.

[0043] The present application has the following beneficial effects:

[0044] 1. Realize the in-vivo, real-time and quantitative evaluation of stool hardness. By integrating multi-modal sensors at the front end of the probe and combining with the precise control of the mechanical arm, the stool can be directly detected inside the rectum, overcoming the subjectivity and hysteresis of traditional in-vitro evaluation methods, and providing objective and quantitative stool hardness indicators for clinical use.

[0045] 2. Multi-dimensional cross-validation is adopted, and the evaluation result is more accurate and reliable. Through motor energy consumption analysis, bioelectrical impedance measurement and pressure sensing, the first, second and third stool hardness indexes are calculated respectively, and finally fused into a comprehensive hardness index. This multi-parameter fusion algorithm can effectively offset the limitations of single measurement method (such as the interference of intestinal environment on pressure and the influence of individual difference on impedance), significantly improving the accuracy and robustness of the evaluation result.

[0046] 3. Provides a core decision basis for personalized and adaptive treatment: the calculated comprehensive hardness index is sent to the auxiliary defecation system in real time, and the system can intelligently adjust the treatment parameters such as water flow pulse intensity, air flow boost frequency and probe rotation speed according to the index. This makes the treatment process dynamically adapt to the stool state of different patients or different periods of the same patient, realizes the leap from "experience-driven" to "data-driven", improves the efficiency of defecation assistance, effectively avoids tissue damage or poor effect caused by improper parameter setting, and greatly improves the safety and comfort of treatment. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 A flowchart of a stool hardness evaluation method for an auxiliary defecation system provided by the present application;

[0048] Figure 2 An auxiliary defecation device schematic diagram of an auxiliary defecation system provided by the present application;

[0049] Figure 3 A structural block diagram of a stool hardness evaluation system for an auxiliary defecation system provided by the present application.

[0050] In the drawings, the components represented by the respective reference numerals are listed as follows: 1 - mechanical arm, 2 - probe, 3 - motor. DETAILED DESCRIPTION

[0051] For a further understanding of the present application, reference will be made to the following description taken in conjunction with the accompanying drawings and embodiments. The following detailed description illustrates embodiments of the application by way of example and not by way of limitation. It is to be understood that this description will be based upon the figures described below and the examples provided. It is also to be understood that only the parts related to the application are shown in the drawings for the sake of convenience of description.

[0052] As Figure 1 The present embodiment provides a feces hardness evaluation method for an auxiliary defecation system, which comprises:

[0053] Step S1: control the mechanical arm to insert the probe into the rectum through the anus, and the probe has a sensor coaxially integrated at the front end. The sensor comprises a pressure sensor and a bioelectrical impedance measurement electrode.

[0054] Specifically, as Figure 2 shown, an auxiliary defecation device of an auxiliary defecation system has a pressure sensor and a bioelectrical impedance measurement electrode coaxially integrated at the front end of the probe. This structure design ensures that the sensor can be in direct contact with the feces sample. The control unit drives the mechanical arm to smoothly insert the probe into the rectal area through the anal channel. In this process, the motion trajectory and force of the mechanical arm are monitored in real time to avoid unnecessary mechanical damage to the intestinal tissue.

[0055] When the probe travels in the rectal cavity, the integrated sensor starts to synchronously collect original physical signals. The pressure sensor continuously monitors the pressure value borne by the probe in the axial direction, and the output signal is a voltage value, which is in a linear relationship with the axial pressure borne by the front end of the probe. The signal processing module in the control unit samples and digitizes these voltage signals to obtain a series of discrete pressure data points. The change trend of these pressure data points is used to judge whether the probe is in contact with the intestinal wall or feces. For example, when the pressure data shows a step increase in a short time, it indicates that the feces surface may have been touched. At the same time, the bioelectrical impedance measurement electrode applies a safe, specific frequency micro-current excitation signal to the surrounding tissue and measures the voltage response generated thereby. The bioelectrical impedance measurement is performed in a dual-frequency measurement mode, i.e., impedance is measured at two specific frequency points, i.e., low frequency and high frequency. The measured original complex impedance data are transmitted to the control unit.

[0056] Pressure data and bioelectrical impedance parameters function synergistically in the data processing workflow. The mechanical contact signal provided by the pressure sensor serves as a criterion for triggering in-depth bioelectrical impedance analysis. Specifically, when the pressure data exceeds a preset contact threshold, the control unit marks that time point and extracts the phase angle and extracellular fluid ratio data calculated by the bioelectrical impedance measurement electrodes at the same time or within a time window. This synchronicity and correlation in data acquisition ensures that subsequent stiffness assessments are based on multimodal information from a state where the probe has indeed made physical contact with the feces.

[0057] This combination of technical features solves the technical problems of single signals being easily interfered with in the complex rectal environment, making it difficult to reliably identify feces and assess their physical properties. Pressure sensing provides the mechanical basis for contact judgment, while bioelectrical impedance measurement provides internal information reflecting the composition and state of feces. The two techniques are functionally mutually supportive: the pressure signal confirms the spatial location and timing of the measurement, while the impedance signal reveals the intrinsic properties of the analyte. Their interaction enables the system to accurately distinguish between friction between the probe and the intestinal wall and actual contact with the feces, thus providing a reliable, multi-dimensional input data foundation for subsequent fecal hardness calculations. Ultimately, this achieves the technical effect of objectively and quantitatively assessing fecal hardness in the living intestine.

[0058] Step S2: Just as the probe passes through the anal sphincter but before contacting the feces, the robotic arm stops its axial feed and drives the probe to rotate via a motor until the specified time. Stop when idling and calculate energy consumption. .

[0059] Specifically, since the assisted defecation system is mainly designed for patients with fecal impaction, such as... Figure 2 The probe end of the auxiliary defecation device of the assisted defecation system shown has a protruding ridge. When the probe comes into contact with feces, the probe rotates and drives the surface of the protruding ridge to rub and dry the feces, causing it to break down. Therefore, the harder the feces, the higher the energy consumption when the probe rotates when it comes into contact with the feces. In order to achieve accurate quantitative assessment of fecal hardness, it is necessary to establish a stable energy consumption measurement benchmark so that when the probe rotates when it comes into contact with feces, only the energy consumption of the probe rotation caused by fecal friction is calculated. Therefore, it is necessary to first exclude the friction force applied to the probe by the anal sphincter and the friction force applied to the probe by the rectal cavity.

[0060] Because the anal sphincter and the distal end of the rectal cavity are approximately funnel-shaped, the frictional force exerted by the anal sphincter on the probe per unit area is greater than the frictional force exerted by the rectal cavity on the probe during probe insertion. Therefore, the energy consumption caused solely by the frictional force exerted by the anal sphincter on the probe during probe rotation is defined as idling energy consumption. When the probe just passes through the anal sphincter and has not yet contacted the stool, the mechanical arm stops axial feeding and rotates the probe by motor drive to a time When the probe just passes through the anal sphincter and has not yet contacted the stool, the mechanical arm stops axial feeding and rotates the probe by motor drive to a time The signal processing logic in the control unit processes the collected current data, identifies and extracts the current data, which is defined as motor current . The calculation of idle energy consumption is essentially the integration of electric power in the time dimension. Specifically, the control unit multiplies the constant bus voltage U with the extracted current , obtains the average electric power in the idle state, and then multiplies the average electric power with the constant idle time , thereby calculating the total energy consumed in the entire idle time period, i.e. the idle energy consumption .

[0061] Therefore, the idle energy consumption calculation formula is:

[0062]

[0063] wherein, is the motor bus voltage, is the motor current at this step, is the probe rotation time.

[0064] The calculation of idle energy consumption solves the technical problem of separating and quantifying the probe rotation non-stool reason loss in a complex internal environment. In the subsequent step, when the probe contacts the stool and is subjected to a load, the total energy consumption of the motor will include the idle energy consumption and the work done to overcome the resistance of the stool. The prior determination of idle energy consumption provides a reliable subtraction benchmark for accurately deducting the system background loss from the total energy consumption, ensuring the accuracy and reliability of the final stool hardness evaluation results.

[0065] Step S3: The mechanical arm continues to advance axially by a unit distance , the probe still rotates at the same speed in the same time in the non-stool area, and the unit distance rectal wall friction energy consumption is calculated.

[0066] After completing the idle energy consumption benchmark measurement, the probe rotation loss analysis enters the quantification stage of the influence of rectal wall friction. The control unit issues instructions to the mechanical arm to accurately advance along the axial direction of the rectal cavity by a preset unit distance d. After the advancement is completed, the probe maintains the same rotation speed as in the idle stage, and the sensor data continuously confirms that the front end of the probe is still in the rectal area that has not contacted the stool. This combination of actions simulates the typical working conditions of the probe traveling in the intestinal tract and sliding friction with the intestinal wall.

[0067] The propulsion action of the mechanical arm introduces mechanical interaction between the probe and the rectal wall. At this time, the load of the driving motor changes compared to the pure idling state, and the waveform and amplitude of the operating current change accordingly. The data acquisition system of the control unit synchronously records the bus voltage U and real-time current of the motor at this stage. The bus voltage U remains constant, and the current data reflects the power required to maintain the rotation of the probe in contact with the intestinal wall.

[0068] Friction energy consumption per unit distance of rectal wall The calculation is based on the energy difference principle. The processing logic of the control unit first calculates the total energy consumption of the current step using the same algorithm as the calculation of the idling energy consumption , i.e., using the bus voltage U, current and rotation time . This total energy consumption includes two main parts: the inherent idling loss of the system and the additional energy consumption due to the friction between the probe and the rectal wall. In order to accurately separate the latter, the calculation algorithm performs a subtraction operation to subtract the pre-stored idling energy consumption reference value from the current total energy consumption.

[0069] In this embodiment, the calculation formula for the friction energy consumption per unit distance of rectal wall is as follows:

[0070]

[0071] wherein, is the motor current at this step, is the idling energy consumption, is the bus voltage of the motor, is the rotation time of the probe, is the friction energy consumption per unit distance of rectal wall.

[0072] This step directly solves the key technical problem in in vivo assessment that it is difficult to distinguish between fecal resistance and inherent resistance of the intestinal environment. The rectal wall itself has viscous friction to the probe, and if this amount is not quantified and excluded, this part of the energy consumption will be misjudged as caused by fecal hardness when contacting feces later, resulting in a systematic positive deviation in the evaluation result. By pre-measuring and establishing the friction energy consumption per unit distance in the feces-free area, a calibration coefficient is introduced for subsequent calculation, so that it can be accurately deducted when calculating the net action energy consumption of feces. In this way, the interference of the intestinal environment on energy consumption measurement is effectively eliminated, significantly improving the accuracy and specificity of subsequent calculation of fecal hardness index, and laying a reliable foundation for achieving precise personalized assessment.

[0073] Step S4: The mechanical arm continues to advance axially by a distance The mechanical arm immediately stops axial feeding and keeps the probe in contact with the feces as soon as the sensor detects contact with the feces.

[0074] Specifically, when the pressure sensor detects a sudden increase in pressure value to a preset pressure threshold and the bioelectrical impedance measurement electrode samples a change in bioelectrical impedance phase angle to a preset phase angle threshold, it is determined that the probe has contacted the feces.

[0075] Specifically, after completing the rectal wall friction reference measurement, the technical solution enters the judgment stage of the feces contact point. The control unit instructs the mechanical arm to continue advancing the probe along the axial direction, and the advancing distance in this stage is a variable D determined by the sensor feedback in real time. During the advancing process, the pressure sensor at the front end of the probe and the bioelectrical impedance measurement electrode perform synchronous and continuous data acquisition, and the obtained data stream is transmitted to the control unit in real time for processing.

[0076] The pressure sensor generates a series of pressure data points corresponding to the axial pressure values experienced by the probe when traveling in the rectum. When the probe does not contact the feces, the pressure data fluctuates at a low level, mainly reflecting the slight contact of the intestinal wall and the fluid resistance of the intestinal contents. The bioelectrical impedance measurement electrode continuously generates phase angle data reflecting the dielectric properties of the tissue. When the rectal cavity or only the intestinal wall is contacted, the phase angle data remains in a relatively stable range. The control unit has a preset pressure threshold and a phase angle threshold, which are set based on prior knowledge of the physical properties of intestinal tissue and feces. For example, when the pressure increases ΔP≥0.2kPa and the phase angle changes ≥5°, the control unit decision algorithm determines that the front end of the probe has reliably contacted the surface of the feces. Once this condition is met, the control unit immediately sends a stop command to the mechanical arm to terminate the axial feeding motion and keep the probe in contact with the feces.

[0077] In this way, the key problem of a single sensor being unable to reliably distinguish between feces contact and intestinal wall folds or other tissue interference in the non-visible rectal environment is directly solved. A single pressure increase may be caused by touching the intestinal wall, and a single phase angle change may also be caused by the probe being too close to the intestinal wall. By requiring both types of sensing signals to meet the threshold condition simultaneously, the probability of misjudgment is greatly reduced. The technical effect lies in providing an accurate and reliable starting time and contact state for the subsequent feces hardness measurement step, ensuring that the subsequent energy consumption measurement and calculation are based on the true interaction between the probe and the feces, thereby ensuring the accuracy and effectiveness of the final feces hardness evaluation results from the source.

[0078] Step S5: Drive the probe to rotate again at the same speed for the same time Calculate the total energy consumption after contacting the feces .

[0079] This step is idle energy consumption The calculation principle is similar, and the total energy consumption of the probe rotating after contacting the feces is not described in detail The calculation formula is:

[0080]

[0081] Among them, is the motor current of this step, is the bus voltage of the motor, is the probe rotation time, is the total energy consumption of the probe rotating after contacting the feces.

[0082] Step S6: Calculate the first feces hardness index = - - , wherein is the energy-hardness calibration coefficient.

[0083] Specifically, after successfully detecting the contact of the feces and completing the energy consumption measurement in the contact state, the first feces hardness index can be determined. This calculation is based on a comprehensive data processing formula: = [ - - ]. In this formula, represents the total energy consumed by the probe contacting the feces and rotating for a period of time , which is measured and recorded by the control unit in real time during the contact step. is the pre-measured and stored system idle energy consumption reference, is the pre-measured unit distance rectal wall friction energy consumption, D is the actual pushing distance of the mechanical arm at the moment of detecting the contact of the feces, d is the unit pushing distance set before measuring , obviously, d≠0, is an energy-hardness calibration coefficient determined by calibration experiments in advance.

[0084] The physical meaning of is to model and estimate the total rectal wall friction energy consumption of the probe during the entire working stroke, wherein (D / d) normalizes the actual pushing distance D to multiple of unit distance d, and multiplying E1 obtains the energy consumption due to rectal wall friction on distance D. Adding an E1 is to consider that in the process of measuring E1 itself, the probe also pushes a distance d and generates additional friction energy consumption, which needs to be included in the total friction interference. Subsequently, the calculation logic executes The subtraction operation aims to subtract the parasitic energy consumption due to the rectal wall friction and the inherent idle loss of the system from the measured total energy consumption E2, so as to isolate the net energy consumption purely for overcoming the mechanical resistance of the stool. Finally, the calculated net energy consumption value is multiplied by the calibration coefficient K1. K1, as a proportional factor, establishes the quantitative conversion relationship between the two different physical quantities of "consumed energy" and "stool hardness", and its value represents the hardness value corresponding to unit net energy consumption, thereby mapping the energy scale to a hardness index with clear physical meaning .

[0085] Further, the energy-hardness calibration coefficient K1 is obtained by the following steps:

[0086] Step S601: Prepare a plurality of standard stool simulants with different known hardness values ;

[0087] Step S602: Place the standard stool simulants in the rectal phantom, control the mechanical arm and the probe, and repeatedly execute the steps S1 to S5 to measure and record the idle energy consumption , the rectal wall friction energy consumption per unit distance , the total energy consumption after contacting the stool , and the pushing distance D corresponding to each standard stool simulant;

[0088] Step S603: Calculate the net energy consumption ;

[0089] Step S604: Perform linear regression analysis with the net energy consumption as the independent variable and the known hardness value as the dependent variable, and fit a linear equation of ;

[0090] Step S605: Determine the slope of the linear equation as the energy-hardness calibration coefficient .

[0091] Further, when the contact with the stool is detected in step S4, the bioelectrical impedance measurement electrodes synchronously collect the dual-frequency bioelectrical impedance data, and the extracellular fluid proportion and the phase angle are fitted by using the Cole-Cole model to calculate the second stool hardness index , wherein​​​​ , is the reference value when the stool is completely softened, is the resistance-impedance calibration coefficient.

[0092] Specifically, since the stool hardness is considered only from the single dimension of the probe power consumption, it is not completely reliable, such as non-stool foreign matter inside the rectum, and the hardness is easily misjudged from the power consumption alone. Therefore, the dual-frequency bioelectrical impedance data are introduced to judge the stool hardness, and the hardness evaluation path based on the bioelectrical impedance principle is started synchronously at the moment when the probe contacts the stool. At this time, the bioelectrical impedance measurement electrodes integrated in the front end of the probe are activated, and in a very short time window, microampere-level alternating current signals of two specific frequencies of low frequency and high frequency are applied to the stool sample in turn. The electrodes synchronously measure the voltage response generated under different frequency current excitation, thereby obtaining a set of complex bioelectrical impedance raw data. This dual-frequency measurement mode can capture the characteristics of impedance changing with frequency, which is closely related to the microstructure of biological tissues.

[0093] After obtaining the raw impedance data, the processing logic in the control unit starts to perform calculations. First, the complex impedance data measured at low frequency and high frequency are processed, and the resistance component representing the resistance characteristic, which represents the proportion of extracellular fluid, and the phase angle representing the capacitance characteristic are calculated respectively. The resistance component mainly reflects the conductivity of extracellular fluid, and the phase angle is associated with the structural integrity of the cell membrane and the intracellular fluid volume. The hardness of the stool is related to its water content and cell structure integrity, and dry and hard stool usually shows higher resistance and lower phase angle. The formula for calculating the second stool hardness index is In this formula, and are real-time measurement values, and and are reference benchmarks established by experiments in advance, representing the expected resistance value and phase angle value of the stool in the ideal softening state. is a calibration coefficient that converts the impedance ratio relationship into a hardness scale, and the calibration process can refer to It should be noted that when the water content of the stool is extremely high (close to an aqueous solution) and the cell residue is extremely small, can tend to , but due to the influence of intestinal mucin and electrolytes, the actual measured is still 0.3°-0.8° larger than , so – ≠ 0, that is, the second stool hardness index In the formula, the denominator cannot be 0.

[0094] The physical logic of this calculation process lies in establishing an evaluation index directly related to the composition and structure of feces. Numerator ( This quantifies the degree of deviation of the current fecal resistivity from its fully softened state; a greater deviation generally indicates a higher degree of dryness. The denominator ( This quantifies the deviation of the current fecal phase angle from its softened state, a deviation related to the degree of cellular structural damage. Using this ratio as the basis for evaluation is significant because it simultaneously considers two key electrical properties of feces: conductivity (resistance) reflecting water content and dielectric properties (phase angle) reflecting microstructure. This approach allows... The index can more comprehensively reflect the physical state of feces, rather than relying on a single parameter. The extreme values ​​of the second fecal hardness index provide the ability to obtain the intrinsic electrical parameters of feces in real time within the anorectal region, reflecting the structural state of fecal hardness.

[0095] This approach addresses the technical challenge of single mechanical assessments being affected by fecal adhesion or probe contact conditions, providing a complementary dimension for hardness assessment based on material composition. By introducing electrical measurements directly related to fecal microstructure and moisture content, an assessment channel independent of mechanical action is added. This channel is more sensitive to changes in fecal composition, thereby enhancing the system's ability to distinguish between different types of feces and improving the reliability of the assessment results. This provides crucial compositional information for subsequent data fusion.

[0096] Furthermore, after step S6, the method also includes recording the pressure value collected by the pressure sensor at this time. The robotic arm continues to advance axially a unit distance d, and the pressure value is recorded. Calculate the third fecal hardness index ,in This is the pressure-hardness calibration factor.

[0097] After completing the initial assessment based on energy consumption and electrical impedance, a further assessment step based on quasi-static pressure measurement is performed to obtain the third fecal hardness index. This process begins with the probe at the confirmed fecal contact location. The control unit records the pressure value measured by the pressure sensor in this state, denoted as . The pressure This represents the static pressure that maintains the initial contact between the probe and the fecal surface. Subsequently, the control unit commands the robotic arm to precisely advance a unit distance d along the probe's axis. After the robotic arm completes this unit distance advance and comes to a stop again, the control unit immediately records the new reading from the pressure sensor, denoted as . .

[0098] Calculate a third stool hardness index The formula is In this processing logic, characterizes the increased pressure required to embed the probe into the stool by a unit distance d, i.e. the pressure increment per unit embedding depth. This pressure increment directly reflects the mechanical stiffness of the stool against the invasion of the probe. is a pressure calibration coefficient determined in advance through calibration experiments, which serves to convert the physical dimension of the pressure increment into a dimensionless or specific standard unit corresponding to the hardness index, and its acquisition mechanism can be referred to in The local mechanical hardness of the stool is quantified by calculating the rate of change of pressure with respect to displacement. The algorithm features, mechanical control, and pressure sensing are functionally mutually supportive and interactive: mechanical control creates standardized deformation conditions, pressure sensing provides mechanical data under these conditions, and the algorithm converts these data into a hardness index representing material properties. The three are closely integrated to form a complete quasi-static hardness measurement method.

[0099] This technical means aims to solve the technical problem that pure dynamic energy consumption evaluation may not be sensitive to certain viscoelastic stools, and provides a supplementary evaluation dimension based on static or quasi-static mechanical properties. For example, for some stools with loose internal structure but certain viscosity, the energy consumption of rotary cutting may not be high, but they may exhibit significant resistance when slowly pressed, at which time the index can effectively capture this mechanical property. By introducing a pressure-displacement relationship measurement based on a small embedding displacement, the technical solution can evaluate the elastic or plastic deformation resistance of the stool at a low strain rate, which provides another independent evaluation perspective for stool hardness based on direct mechanical contact, enhances the overall system's comprehensive perception of stools with different mechanical properties, and makes the final comprehensive hardness judgment more stable and accurate.

[0100] Further, the is weighted and fused into a comprehensive stool hardness index , wherein are the corresponding weights of , and ; the is sent to the auxiliary defecation system for real-time adjustment of the water flow pulse intensity, air flow boost frequency, and probe rotation speed, to realize personalized defecation assistance.

[0101] Specifically, after obtaining three independent stool hardness indices based on energy, bioelectrical impedance, and pressure respectively, the data fusion and closed-loop control phase is entered, which is executed by the control unit, and the core is to integrate the above multi-source heterogeneous evaluation data into a unified comprehensive hardness index The fusion algorithm uses a weighted summation mathematical form, expressed as: In this formula, These are pre-set weighting coefficients stored in the control unit, such as 0.5, 0.2, and 0.3. The specific weighting coefficients are assigned based on the physical principles underlying each sub-index and their reliability in a specific clinical scenario, pre-configured. For example, in routine assessments, weighting coefficients based on energy consumption... The index may be given a higher weight. Because it directly reflects the overall mechanical resistance of feces; when the system detects that the feces may have special viscous properties, it uses bioelectrical impedance analysis. Index weight It can be adjusted to focus more on component analysis; while when it is necessary to assess the local elastic modulus of feces, it can be based on quasi-static pressure. Index weight The corresponding enhancement can be achieved. The control unit retrieves these three sub-indices and their corresponding weight values ​​from memory, performs scalar multiplication and addition operations, and calculates the comprehensive hardness index. .

[0102] Calculated As a standardized hardness indicator, it is transmitted in real time to the actuator control module of the assisted defecation system via the data communication interface of the control unit. This control module has pre-stored... Strategies that map to specific treatment parameters, for example, for higher... In response to the increased mechanical resistance, the system will correspondingly enhance the intensity of the water flow pulse, increase the frequency of the airflow boost, and may adjust the probe's rotation speed. This directly solves the technical problems of single assessment methods being susceptible to interference in complex internal environments, having limited assessment dimensions, and thus leading to mismatched treatment parameter settings. Through multi-source information fusion, the robustness and comprehensiveness of fecal hardness assessment are significantly improved, thereby driving the assisted defecation system to achieve dynamic, personalized treatment that precisely matches the measured physical state of the feces, ultimately improving the efficiency and safety of defecation assistance.

[0103] Secondly, please refer to Figure 3 This application illustrates a fecal hardness assessment system for an auxiliary defecation system, which implements the fecal hardness assessment method for an auxiliary defecation system in the first aspect, including:

[0104] The mechanical arm 1; the probe 2, which is operatively connected to the mechanical arm 1 and is configured to be transanally inserted into the rectum; the motor 3, which is drivingly connected with the probe 2 and is used to drive the probe 2 to rotate; the sensor, which is coaxially integrated at the front end of the probe 2 and is used to detect the contact between the probe 2 and the feces, and specifically comprises a pressure sensor and a bioelectrical impedance measurement electrode; the control unit, which is in communication connection with the mechanical arm 1, the sensor and the motor 3; the first feces hardness index calculation unit, which is in the control unit and calculates the first feces hardness index according to the motor 3 working energy consumption during the process that the probe 2 is fed into the rectum to contact the feces; the second feces hardness index calculation unit, which is in the control unit and calculates the second feces hardness index according to the double-frequency bioelectrical impedance data of the feces measured by the bioelectrical impedance measurement electrode; the third feces hardness index calculation unit, which is in the control unit and calculates the third feces hardness index according to the pressure data detected by the pressure sensor; and the feces comprehensive hardness index calculation unit, which is in the control unit and calculates the comprehensive hardness index of the feces according to the first feces hardness index, the second feces hardness index and the third feces hardness index.

[0105] The probe integrated with the sensor is inserted into the rectum by controlling the mechanical arm in the embodiment; after the probe passes through the anal sphincter, the idling energy consumption is measured; the unit distance is pushed, and the friction energy consumption of the rectal wall is measured; the total energy consumption is measured by continuing to push to contact the feces; the first feces hardness index is calculated based on the idling energy consumption, the friction energy consumption and the total energy consumption, and then the second feces hardness index is calculated by synchronously using the component data obtained by the bioelectrical impedance measurement electrode, and the third feces hardness index is calculated by using the pressure data obtained by the pressure sensor, and the three indexes are weighted and fused into the feces comprehensive hardness index. The feces hardness is evaluated in real time and accurately in the anus and intestines by the multi-modal sensing and data fusion of the present application, and a reliable basis is provided for the personalized adjustment of the parameter adjustment of the auxiliary defecation system.

[0106] The above is only a specific embodiment of the present specification, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described system, module and unit can refer to the corresponding process in the foregoing method embodiment, which will not be described here. It should be understood that the protection scope of the present specification is not limited to this, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed in the present specification, and these modifications or replacements should be covered within the protection scope of the present specification.

Claims

1. A fecal hardness assessment system for an auxiliary defecation system, characterized in that, include: robotic arm (1); A probe (2), which is operatively connected to the robotic arm (1) and configured to be inserted into the rectum via the anus; Motor (3), which is connected to the probe (2) for driving the probe (2) to rotate; The sensor, which is coaxially integrated at the front end of the probe (2), is used to detect the contact between the probe (2) and the feces, and specifically includes a pressure sensor and a bioelectrical impedance measurement electrode; The control unit is communicatively connected to the robotic arm (1), the sensor, and the motor (3); The first fecal hardness index calculation unit, within the control unit, calculates the first fecal hardness index based on the energy consumption of the motor (3) during the process of the probe (2) feeding into the rectum and contacting the feces. The calculation method for the first fecal hardness index is as follows: ,in This is the energy-hardness calibration factor. Energy consumption during idling. The energy consumption per unit distance of rectal wall friction. The total energy consumption after contact with feces is given, D is the distance the probe travels from the area without feces to the area in contact with feces, and d is the unit travel distance. The second fecal hardness index calculation unit, located within the control unit, calculates the second fecal hardness index based on the dual-frequency bioelectrical impedance data of the feces measured by the bioelectrical impedance measuring electrode. The calculation method for the second fecal hardness index is as follows: Where K2 is the electrical impedance-hardness calibration coefficient, The extracellular fluid ratio is obtained by fitting dual-frequency bioelectrical impedance data. The phase angle is obtained by fitting dual-frequency bioelectrical impedance data. , This serves as the baseline value for the proportion of extracellular fluid and the phase angle in the stool during softening. The third fecal hardness index calculation unit, located within the control unit, calculates the third fecal hardness index based on the pressure data detected by the pressure sensor. The calculation method for the third fecal hardness index is as follows: ,in This is the pressure-hardness calibration factor. This is the pressure value when the probe initially contacts the feces. This represents the pressure value after the probe continues to advance a unit distance d; The fecal composite hardness index calculation unit, located within the control unit, calculates the composite hardness index of the feces based on the first fecal hardness index, the second fecal hardness index, and the third fecal hardness index. The calculation method for the composite hardness index is as follows: ,in , , The weights for the first, second, and third fecal hardness indices are respectively, and .

2. The fecal hardness assessment system for an auxiliary defecation system as described in claim 1, characterized in that, The system is used to implement the following steps: Step S1: Control the robotic arm to insert the probe into the rectum through the anus; Step S2: Just as the probe passes through the anal sphincter but before contacting the feces, the robotic arm stops its axial feed and drives the probe to rotate via a motor until the specified time. Stop when idling and calculate energy consumption. ; Step S3: The robotic arm continues to advance axially a unit distance. The probe continues to rotate at the same speed and for the same amount of time in the area without feces. Calculate the energy consumption per unit distance of rectal wall friction. ; Step S4: The robotic arm continues to advance axially a certain distance. The robotic arm immediately stops axial feeding and keeps the probe in contact with the feces until the sensor detects contact with the feces; Step S5: Drive the probe to rotate again at the same speed for the same amount of time. Calculate the total energy consumption after contact with feces. .

3. The fecal hardness assessment system for an auxiliary defecation system as described in claim 2, characterized in that, The idling energy consumption The calculation formula is: ； in, The voltage at the motor bus is... The motor current in step S2, This represents the probe rotation time.

4. The fecal hardness assessment system for an auxiliary defecation system as described in claim 2, characterized in that, The total energy consumption after contact with feces The calculation formula is: ； in, The voltage at the motor bus is... The motor current in step S5, This represents the probe rotation time.

5. The fecal hardness assessment system for an auxiliary defecation system as described in claim 2, characterized in that, The energy consumption per unit distance of rectal wall friction The calculation formula is: ； in, The voltage at the motor bus is... The motor current in step S3, This represents the probe rotation time.

6. The fecal hardness assessment system for an auxiliary defecation system as described in claim 2, characterized in that, Specifically, the sensor detects contact with feces when: when the pressure sensor detects a sudden increase in pressure value to a preset pressure threshold and the bioelectrical impedance phase angle sampled by the bioelectrical impedance measurement electrode changes to a preset phase angle, it is determined that the probe has come into contact with feces.

7. The fecal hardness assessment system for an auxiliary defecation system as described in claim 2, characterized in that, The energy-hardness calibration coefficient is obtained through the following steps: Step S601: Prepare multiple units with different known hardness values Standard fecal simulants; Step S602: Place the standard fecal simulant in the rectal phantom, control the robotic arm and probe, and repeat steps S1 to S5 to measure and record the idle energy consumption of each standard fecal simulant. Energy consumption per unit distance of rectal wall friction Total energy consumption after contact with feces And the propulsion distance D; Step S603: Calculate the net energy consumption for each standard fecal simulant. ; Step S604: Based on the net energy consumption As the independent variable, the known hardness value is used. Using [variable name] as the dependent variable, perform linear regression analysis and obtain the fitted result. The linear equation; Step S605: Calculate the slope of the linear equation. The energy-hardness calibration coefficient was determined to be... .

Images