Gait dynamic stability assessment methods, devices, equipment and storage media

Abstract

This invention discloses a method, apparatus, device, and storage medium for evaluating gait dynamic stability. The method includes: acquiring the displacement and velocity of the human body's center of mass in the sagittal plane at various moments within a single support phase time period, where the single support phase time period is from the moment the toes leave the ground to the moment the heel touches the ground; calculating the velocity stability domain in the sagittal plane using the displacement and velocity of the center of mass; plotting the velocity stability domain curve based on the velocity stability domain, and continuously differentiating the velocity stability domain curve to obtain the acceleration stability domain curve; quantifying the fluctuation degree of the acceleration stability domain curve, and evaluating gait stability based on the quantified fluctuation degree, with more severe fluctuation indicating poorer gait stability. This invention analyzes the acceleration stability domain curve of the human gait in the sagittal plane within a single support phase time period and analyzes gait stability based on the fluctuation degree of the acceleration stability domain curve; the more severe the fluctuation, the worse the gait stability.

Description

Technical Field

[0001] This application relates to the field of gait analysis technology, and in particular to a method, apparatus, device and storage medium for evaluating gait dynamic stability. Background Technology

[0002] Walking is the most basic form of human movement and the primary dynamic activity in the daily lives of the elderly. Because the human body is a complex, multi-jointed, flexible organism, and given the unique nature of bipedal walking, upright walking is a complex behavioral process controlled by the real-time dynamic adjustment and compensation of the body's center of mass (COM), characterized by continuous and variable changes and the need to maintain instantaneous dynamic balance at all times. Normal gait includes two basic elements: first, movement. Both lower limbs alternately bear the responsibility of supporting the passenger unit (HAT, i.e., the head, neck, trunk, arms, and other body parts carried during walking), thus moving the passenger unit forward; second, maintaining dynamic stability. Under normal circumstances, the human body relies on the coordinated action of the nervous and musculoskeletal systems to maintain a critically stable state of instantaneous balance during walking, and achieves dynamic stability throughout the entire walking process through continuous changes in posture and fine-tuning of limb movements. Normal gait is characterized by three features: body stability, appropriate stride length, and minimal energy consumption. Healthy young and middle-aged adults with normal limb function can maintain dynamic stability through the coordinated control of the neuromuscular and skeletal systems in normal walking environments. However, as people age, various functions decline, which may lead to sensory impairment, reduced joint flexibility, decreased muscle strength and ligament elasticity, and changes in the structure and function of the feet. All of these problems cause changes in the gait characteristics of the elderly to varying degrees, resulting in a decrease in dynamic stability and thus increasing the risk of falls while walking.

[0003] In recent years, scholars at home and abroad have proposed and developed dynamic stability control theory. Compared with traditional static stability control theory, dynamic stability control theory regards the interaction between COM position and velocity and the relationship with the base of support (BOS) as an indicator of human stability. This deepens the understanding of the human stability control mechanism and can better explain the imbalance and rebalancing problem in the process of human movement. It has important guiding significance for the assessment and intervention of fall risk in the elderly.

[0004] Despite extensive biomechanical studies on tripping by research teams both domestically and internationally, issues remain regarding research methods and parameter inclusion, leading to inconsistencies in results and hindering the development of strategies for tripping and falling prevention and recovery in the elderly. Regarding parameter inclusion, quantifying gait stability and clinical rehabilitation outcomes based on data collected in gait laboratories is one of the mainstream directions in gait research. Since tripping occurs during a single support phase, dynamic stability analysis during this phase is crucial for understanding tripping mechanisms. However, most current dynamic stability studies focus primarily on analyzing specific moments within the single support phase, such as toe-off or heel-to-spot contact. Because gait is a continuous process in real-world gait environments, stability analysis at only a single moment is insufficient to comprehensively reflect the stability issues within the single support phase. Summary of the Invention

[0005] In view of this, this application provides a method, apparatus, device and storage medium for evaluating gait dynamic stability, in order to solve the problem that existing gait stability analysis methods are insufficient to fully reflect the stability of a single support phase.

[0006] To address the aforementioned technical problems, this application provides a gait dynamic stability assessment method, comprising: acquiring the displacement and velocity of the human body's center of mass in the sagittal plane at various moments within a single support phase time period, wherein the single support phase time period is from the moment the toes leave the ground to the moment the heel touches the ground; calculating the velocity stability domain in the sagittal plane using the displacement and velocity of the center of mass; plotting the velocity stability domain curve based on the velocity stability domain, and continuously differentiating the velocity stability domain curve to obtain the acceleration stability domain curve; quantifying the fluctuation degree of the acceleration stability domain curve, and assessing gait stability based on the quantified fluctuation degree, wherein the more severe the fluctuation degree, the worse the gait stability of the human body.

[0007] As a further improvement of this application, the fluctuation degree of the acceleration stability domain curve is quantified, and gait stability is evaluated based on the quantified fluctuation degree. The more severe the fluctuation degree, the worse the gait stability of the human body. This includes: calculating the acceleration stability domain Shannon entropy based on the acceleration stability domain curve using a multifractal algorithm; evaluating gait stability based on the acceleration stability domain Shannon entropy, where a larger acceleration stability domain Shannon entropy indicates a worse gait stability of the human body.

[0008] As a further improvement to this application, based on the multifractal algorithm, the acceleration stability domain Shannon entropy is calculated using the acceleration stability domain curve, including: coarsening the acceleration stability domain curve to obtain a symbol sequence; and using the symbol sequence to calculate the acceleration stability domain Shannon entropy.

[0009] As a further improvement to this application, the calculation process of the Shannon entropy in the acceleration stability region is expressed as follows:

[0010]

[0011] in, Let X represent the Shannon entropy of the acceleration stability region, x represent each sample point of the symbol sequence, P1(x) and P2(x) represent the probability distribution of the random variable of sample x, ω1 and ω2 represent the weights of the random variable, and ω1+ω2=1.

[0012] As a further improvement of this application, the velocity stability domain in the sagittal plane is calculated using the centroid displacement and centroid velocity, including: obtaining the toe point and heel point of the reference foot, and confirming the length of the reference foot based on the toe point and heel point; standardizing the centroid displacement and centroid velocity using the length of the reference foot; and calculating the velocity stability domain using the standardized centroid displacement and standardized centroid velocity.

[0013] As a further improvement to this application, the velocity stability domain calculation process is expressed as follows:

[0014]

[0015]

[0016]

[0017] l fx =x1-x2;

[0018] in, This represents the standardized displacement of the centroid at time t. Let l be the standardized velocity of the center of mass at time t. x The length from the center of mass in the sagittal plane to the ankle, g is the acceleration due to gravity, x1 refers to the toe point, x2 refers to the heel point, and l fx For reference, X is a full length. t Let be the displacement of the centroid at time t. Let be the velocity of the center of mass at time t.

[0019] As a further improvement of this application, the velocity stability domain is based on the inverted pendulum model and is calculated using the displacement and velocity of the center of mass.

[0020] To address the aforementioned technical problems, another technical solution adopted in this application is: providing a gait dynamic stability assessment device, comprising: an acquisition module for acquiring the displacement and velocity of the human body's center of mass in the sagittal plane at various moments within a single support phase time period, wherein the single support phase time period is from the moment the toes leave the ground to the moment the heel touches the ground; a calculation module for calculating the velocity stability domain in the sagittal plane using the displacement and velocity of the center of mass; a plotting module for plotting the velocity stability domain curve based on the velocity stability domain and continuously differentiating the velocity stability domain curve to obtain the acceleration stability domain curve; and an assessment module for quantifying the fluctuation degree of the acceleration stability domain curve and assessing gait stability based on the quantified fluctuation degree, wherein the more severe the fluctuation degree, the worse the gait stability of the human body.

[0021] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide a computer device, the computer device including a processor and a memory coupled to the processor, the memory storing program instructions, and when the program instructions are executed by the processor, causing the processor to perform the steps of the gait dynamic stability evaluation method as described above.

[0022] To solve the above-mentioned technical problems, another technical solution adopted in this application is to provide a storage medium storing program instructions capable of implementing any of the above-mentioned gait dynamic stability evaluation methods.

[0023] The beneficial effects of this application are as follows: The gait dynamic stability assessment method of this application obtains the displacement and velocity of the human body's center of mass in the sagittal plane at each moment within a single support phase time period. Then, it calculates the velocity stability domain in the sagittal plane at each moment within the single support phase time period using the displacement and velocity of the center of mass. Based on the velocity stability domain, it plots the velocity stability domain curve within the single support phase time period. Then, it continuously differentiates the velocity stability domain curve to obtain the acceleration stability domain curve. Finally, it assesses the gait stability of the human body by analyzing the intensity of fluctuations in the acceleration stability domain curve. The more intense the fluctuation, the worse the gait stability of the human body. It extends the time-based gait stability analysis to the entire single support phase to comprehensively analyze the gait stability within the single support phase, thus realizing gait stability analysis in the time dimension. Furthermore, by analyzing the intensity of fluctuations in the acceleration stability domain curve of the human body's center of mass in the sagittal plane, it assesses the stability of the gait within the single support phase, thus realizing gait stability analysis in the spatial dimension. By comprehensively analyzing gait stability in both the time and spatial dimensions, the accuracy of the assessment results is improved. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the gait dynamic stability evaluation method according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of 15 segments and 26 marker points throughout the body according to an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the sagittal inverted pendulum model according to an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the velocity stability domain curve according to an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram illustrating the calculation of the Shannon entropy in the acceleration stability region using the multifractal algorithm according to an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the functional modules of the gait dynamic stability evaluation device according to an embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of the structure of a computer device according to an embodiment of the present invention;

[0031] Figure 8 This is a schematic diagram of the structure of the storage medium according to an embodiment of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0033] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0034] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0035] Figure 1 This is a flowchart illustrating the gait dynamic stability evaluation method according to an embodiment of the present invention. It should be noted that if substantially the same result is obtained, the method of the present invention is not necessarily identical. Figure 1 The illustrated process sequence is limited. For example... Figure 1 As shown, the gait dynamic stability evaluation method includes the following steps:

[0036] Step S101: Obtain the displacement and velocity of the human body's center of mass in the sagittal plane at each moment within the single support phase time period. The single support phase time period is from the moment the toes leave the ground to the moment the heels touch the ground.

[0037] It should be noted that in this embodiment, the right foot is used as the reference foot, and the single support phase time period is defined as the time period between the moment the left foot's toe leaves the ground and the moment the left foot's heel touches the ground. For example... Figure 2 As shown, in this embodiment, the position of the human body's center of mass is obtained by a 15-element mass weighted sum, and the human body measurement parameters are referenced from "Chinese Adult Human Inertial Parameters (GB / T17245-2004)".

[0038] Specifically, this embodiment is based on a single-hinge inverted pendulum model, taking motion data of the right leg during the support phase of walking. This motion data includes the displacement of the center of mass in the sagittal plane. The velocity of the center of mass is then calculated based on this displacement. The formula for calculating the velocity of the center of mass is as follows:

[0039]

[0040] Where V is the velocity of the center of mass, and X t Let X be the displacement of the centroid at time t. t-1 Let Δt be the displacement of the center of mass at time t-1, and Δt be the time interval between time t and time t-1. Using the above formula for calculating the center of mass velocity, the velocity of the center of mass in the sagittal plane can be calculated.

[0041] Step S102: Calculate the velocity stability domain of the sagittal plane using the centroid displacement and centroid velocity.

[0042] It should be noted that the velocity stability domain is based on the inverted pendulum model and is calculated using the displacement and velocity of the center of mass.

[0043] Specifically, the inverted pendulum model is one of the most widely used simplified models in gait analysis. The pendulum bob corresponds to the human body's center of mass, the pendulum rod (l) corresponds to the supporting leg, and the pivot corresponds to the ankle joint. Based on this inverted pendulum model, a velocity stability domain is constructed using the displacement and velocity of the center of mass.

[0044] Furthermore, the steps for calculating the velocity stability domain in the sagittal plane using the centroid displacement and centroid velocity specifically include:

[0045] 1. Obtain the toe point and heel point of the reference foot, and determine the foot length of the reference foot based on the toe point and heel point.

[0046] Specifically, in this embodiment, the right foot is used as the reference foot. The toe point and heel point of the reference foot are obtained, and the length of the reference foot is determined based on the toe point and heel point.

[0047] 2. Standardize the displacement and velocity of the center of mass using the reference length.

[0048] 3. The velocity stability region is calculated using the standardized centroid displacement and standardized centroid velocity.

[0049] Specifically, please refer to Figure 3 , Figure 3 This diagram illustrates a sagittal inverted pendulum model, where the Z-axis is the vertical axis, X is the sagittal axis in the walking direction, COM is the body's center of mass, m is the mass, g is the acceleration due to gravity, lx is the distance from COM to the ankle in the sagittal plane, and u... min and u max These represent the maximum and minimum values ​​of the support surface on the X-axis, approximating the heel and toe points, respectively. u is the instantaneous point of application of the center of plantar pressure (COP). Figure 3 (a), (b), and (c) represent three scenarios of COM and COP on the inner, lateral, and lateral sides of the ankle, respectively.

[0050] In human gait analysis, if the following three assumptions are met: (1) the com position (COM) can completely represent the balance problem of the human body; (2) the distance l from COM to the ankle remains constant; and (3) the COM offset is small relative to the distance l, then the human motion model can be simplified to an inverted pendulum model. This embodiment takes the moment of toe lift-off (TO moment) as an example to analyze the applicability of the inverted pendulum model in the sagittal plane:

[0051] First, considering the case where the relative velocities of COM and BOS are not taken into account, the applicability of the inverted pendulum model in the sagittal plane is analyzed:

[0052] COMx( Figure 3 (x, i.e., the projection position of the human body's center of mass on the sagittal axis) and COP ( Figure 3When u) is on the same side and both sides of the ankle, the angular momentum expression based on Newton's second law, relative to the "axis of rotation" ankle, is as follows:

[0053]

[0054] in, It is the linear acceleration of COM in the X-axis direction.

[0055] In the sagittal axis direction, during the single-leg support phase, COM rotates around the ankle. The angular momentum theorem can be applied, and the angular momentum equation is: COM can describe human stability, and at the moment of toe lift-off, the distance lx from COM to the ankle is constant. Compared with this distance, the COM offset is small. Human sagittal gait analysis conforms to the three assumptions of the inverted pendulum model. Therefore, the inverted pendulum model is suitable for static stability analysis of sagittal gait.

[0056] Secondly, considering the relative velocities of COM and BOS, the applicability of the inverted pendulum model to dynamic stability analysis in the sagittal plane is discussed.

[0057] Dynamic stability analysis shows that when COMx and COP are on the same side and both sides of the ankle, the following results are obtained:

[0058]

[0059] In the formula, x1 refers to the heel point, i.e. Figure 3 u in min x2 refers to the toe point, that is Figure 3 u in max Subtract x1 from both sides of the above formula, then divide both sides by l. fx =(x2-x1), l fx For reference, a sufficiently long time is used to obtain the velocity stability domain representation at time TO:

[0060]

[0061] in: l fx =(x2-x1), COMz is the projection position of the human body's center of mass in the Z-axis direction, anklez is the projection position of the ankle in the Z-axis direction, COMx is the projection position of the human body's center of mass in the X-axis direction, and anklex is the projection position of the ankle in the X-axis direction.

[0062] In summary, in the sagittal axis direction, the COM rotates around the ankle during the single-foot support phase. The dynamic stability analysis of human sagittal gait conforms to the above three assumptions, and the angular momentum theorem can be applied. The inverted pendulum model is suitable for the dynamic stability analysis of sagittal gait.

[0063] Based on the above verification process, the velocity stability domain at time TO is extended to the entire single-support phase time period, and the velocity stability domain is expressed as:

[0064]

[0065]

[0066]

[0067] l fx =x1-x2;

[0068] Where t is a moment within the entire single-support phase time period. This represents the standardized displacement of the centroid at time t. Let l be the standardized velocity of the center of mass at time t. x The length from the center of mass in the sagittal plane to the ankle, g is the acceleration due to gravity, x1 refers to the toe point, x2 refers to the heel point, and l fx For reference, X is a full length. t Let be the displacement of the centroid at time t. Let be the velocity of the center of mass at time t.

[0069] Step S103: Plot the velocity stability domain curve based on the velocity stability domain, and continuously differentiate the velocity stability domain curve to obtain the acceleration stability domain curve.

[0070] Specifically, after obtaining the velocity stability domain at each moment within the single-support phase time period, the velocity stability domain curve is plotted. For example... Figure 4 As shown, a coordinate system is constructed with the standardized center-of-mass displacement as the abscissa and the standardized center-of-mass velocity as the ordinate. The center-of-mass displacement and velocity at each moment are treated as coordinate points, and the velocity stability domain curve is plotted on the coordinate system. Then, by continuously differentiating the velocity stability domain curve, the acceleration stability domain curve can be obtained.

[0071] Step S104: Quantify the fluctuation degree of the acceleration stability domain curve, and evaluate gait stability based on the quantified fluctuation degree. The more severe the fluctuation degree, the worse the gait stability of the human body.

[0072] It should be noted that the acceleration index can more sensitively reflect the degree of influence of different momentum control capabilities on dynamic stability.

[0073] Specifically, after obtaining the acceleration stability domain curve within a single support phase time period, the fluctuation degree of the acceleration stability domain curve is quantified, and then the quantified fluctuation degree is used to evaluate the gait stability of the human body. The more intense the fluctuation degree, the worse the gait stability of the human body, and the smaller the fluctuation degree, the better the gait stability of the human body.

[0074] Furthermore, in this embodiment, Shannon entropy is preferably used to quantify the fluctuation degree of the acceleration stability domain curve. Based on this, step S104 specifically includes:

[0075] 1. Based on the multifractal algorithm, the Shannon entropy of the acceleration stability domain is calculated using the acceleration stability domain curve.

[0076] Specifically, Shannon entropy refers to the complexity of data information, or the degree of irregularity. It measures the uncertainty of a variable; the greater the uncertainty, the higher the Shannon entropy. For random variables, their values ​​are uncertain. Before conducting a random experiment, only the probability distribution of each value is known; after the experiment, the value is known precisely, and the uncertainty disappears completely. Thus, information is obtained through random experimentation, and the amount of this information is exactly equal to the entropy of the random variable. In this sense, entropy can be used as a measure of information. In this embodiment, the physical meaning of Shannon entropy in the acceleration stability region is the intensity of the fluctuations in the acceleration stability region curve. The more intense the fluctuations, the worse the body's momentum control ability and the worse the gait stability.

[0077] Furthermore, based on the multifractal algorithm, the step of calculating the Shannon entropy of the acceleration stability domain using the acceleration stability domain curve specifically includes:

[0078] 1.1. Coarse-grained processing is performed on the acceleration stability domain curve to obtain the symbol sequence.

[0079] 1.2. The Shannon entropy of the acceleration stability domain is calculated using a symbol sequence.

[0080] Specifically, such as Figure 5 As shown, Figure 5 A schematic diagram illustrating the calculation of the Shannon entropy of the acceleration stability region using a multifractal algorithm is shown. The curve formed by connecting rectangular points represents the acceleration stability region curve, while the curve formed by connecting circular points represents the symbol sequence obtained after coarsening. The Shannon entropy of the acceleration stability region is calculated based on the symbol sequence.

[0081] Furthermore, the calculation process for the Shannon entropy in the acceleration stability region is expressed as follows:

[0082]

[0083] in, Let X represent the Shannon entropy of the acceleration stability region, x represent each sample point of the symbol sequence, P1(x) and P2(x) represent the probability distribution of the random variable of sample x, ω1 and ω2 represent the weights of the random variable, and ω1+ω2=1.

[0084] Specifically, assuming there exists a discrete random variable X, P1 and P2 can be viewed as two probability distributions of variable X. The KL divergence can be mathematically expressed as:

[0085]

[0086] Find a method for measuring the difference entropy between probability distributions P1 and P2.

[0087]

[0088] K1 is represented as: Since K1 and I1 are asymmetric, there exists a difference entropy measure L1 relative to i1, which is expressed as:

[0089] L1(P1,P2)=I1(P1,P2)+I2(P2,P2);

[0090] L1 in Boltzmann-Gibbs-Shannon entropy H1(P)=-∑ j P j logP j In Chinese, it is expressed as:

[0091]

[0092] Assuming that the probability distributions P1 and P2 of the random variable X have the same weights, and letting ω1, ω2 ≥ 0, ω1 + ω2 = 1, we get:

[0093]

[0094] Extending to a continuous random variable X, JS1 can be expressed as:

[0095]

[0096] Shannon entropy is a concave function. When P1 = P2 It was just established.

[0097] 2. Gait stability is evaluated based on the Shannon entropy of the acceleration stability region. The larger the Shannon entropy of the acceleration stability region, the worse the gait stability of the human body.

[0098] The gait dynamic stability assessment method in this embodiment obtains the displacement and velocity of the human body's center of mass in the sagittal plane at various moments within a single support phase. It then calculates the velocity stability domain in the sagittal plane at each moment within the single support phase using these displacements and velocities. Based on this velocity stability domain, it plots the velocity stability domain curve for the single support phase and continuously differentiates the curve to obtain the acceleration stability domain curve. Finally, it assesses gait stability by analyzing the intensity of fluctuations in the acceleration stability domain curve; more severe fluctuations indicate poorer gait stability. This method extends time-based gait stability analysis to the entire single support phase, providing a comprehensive analysis of gait stability within that phase, thus achieving gait stability analysis in the time dimension. Furthermore, by analyzing the intensity of fluctuations in the acceleration stability domain curve in the sagittal plane, it assesses gait stability within the single support phase, thus achieving gait stability analysis in the spatial dimension. By comprehensively analyzing gait stability in both the time and spatial dimensions, the accuracy of the assessment results is improved.

[0099] Figure 6 This is a schematic diagram of the functional modules of the gait dynamic stability evaluation device according to an embodiment of the present invention. Figure 6 As shown, the gait dynamic stability evaluation device 20 includes an acquisition module 21, a calculation module 22, a drawing module 23, and an evaluation module 24.

[0100] The acquisition module 21 is used to acquire the displacement and velocity of the human body's center of mass in the sagittal plane at each moment within a single support phase time period, where the single support phase time period is from the moment the toes leave the ground to the moment the heels touch the ground.

[0101] Calculation module 22 is used to calculate the velocity stability domain of the sagittal plane using the centroid displacement and centroid velocity;

[0102] The plotting module 23 is used to plot the velocity stability domain curve based on the velocity stability domain, and to continuously differentiate the velocity stability domain curve to obtain the acceleration stability domain curve.

[0103] Evaluation module 24 is used to quantify the fluctuation of the acceleration stability domain curve and evaluate gait stability based on the quantified fluctuation. The more severe the fluctuation, the worse the gait stability of the human body.

[0104] Optionally, the evaluation module 24 performs the operation of quantifying the fluctuation degree of the acceleration stability domain curve and evaluating gait stability based on the quantified fluctuation degree. The more severe the fluctuation degree, the worse the gait stability of the human body. Specifically, this includes: calculating the acceleration stability domain Shannon entropy based on the acceleration stability domain curve using a multifractal algorithm; evaluating gait stability based on the acceleration stability domain Shannon entropy, where a larger acceleration stability domain Shannon entropy indicates a worse gait stability of the human body.

[0105] Optionally, the evaluation module 24 performs an operation based on a multifractal algorithm to calculate the Shannon entropy of the acceleration stability domain using the acceleration stability domain curve. Specifically, this includes: coarsening the acceleration stability domain curve to obtain a symbol sequence; and calculating the Shannon entropy of the acceleration stability domain using the symbol sequence.

[0106] Optionally, the calculation process of the Shannon entropy in the acceleration stability region is expressed as follows:

[0107]

[0108] in, Let X represent the Shannon entropy of the acceleration stability region, x represent each sample point of the symbol sequence, P1(x) and P2(x) represent the probability distribution of the random variable of sample x, ω1 and ω2 represent the weights of the random variable, and ω1+ω2=1.

[0109] Optionally, the calculation module 22 performs the operation of calculating the velocity stability domain in the sagittal plane using the centroid displacement and centroid velocity, specifically including: obtaining the toe point and heel point of the reference foot, and confirming the length of the reference foot based on the toe point and heel point; standardizing the centroid displacement and centroid velocity using the length of the reference foot; and calculating the velocity stability domain using the standardized centroid displacement and standardized centroid velocity.

[0110] Optionally, the velocity stability domain calculation process is expressed as follows:

[0111]

[0112]

[0113]

[0114] l fx =x1-x2;

[0115] in, This represents the standardized displacement of the centroid at time t. Let l be the standardized velocity of the center of mass at time t. x The length from the center of mass in the sagittal plane to the ankle, g is the acceleration due to gravity, x1 refers to the toe point, x2 refers to the heel point, and l fx For reference, X is a full length. t Let be the displacement of the centroid at time t. Let be the velocity of the center of mass at time t.

[0116] Optionally, the velocity stability domain is based on the inverted pendulum model and is calculated using the centroid displacement and centroid velocity.

[0117] For further details regarding the implementation techniques of each module in the gait dynamic stability evaluation device of the above embodiments, please refer to the description in the gait dynamic stability evaluation method of the above embodiments, which will not be repeated here.

[0118] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0119] Please see Figure 7 , Figure 7 This is a schematic diagram of the structure of a computer device according to an embodiment of the present invention. Figure 7 As shown, the computer device 30 includes a processor 31 and a memory 32 coupled to the processor 31. The memory 32 stores program instructions. When the program instructions are executed by the processor 31, the processor 31 performs the steps of the gait dynamic stability evaluation method described in any of the above embodiments.

[0120] The processor 31 can also be referred to as a CPU (Central Processing Unit). The processor 31 may be an integrated circuit chip with signal processing capabilities. The processor 31 can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. A general-purpose processor can be a microprocessor or any conventional processor.

[0121] See Figure 8 , Figure 8 This is a schematic diagram of the structure of the storage medium according to an embodiment of the present invention. The storage medium of this embodiment stores program instructions 41 capable of implementing the above-described gait dynamic stability evaluation method. These program instructions 41 can be stored in the storage medium in the form of a software product, including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks, or computer devices such as computers, servers, mobile phones, and tablets.

[0122] In the several embodiments provided in this application, it should be understood that the disclosed computer devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0123] Furthermore, the functional units in the various embodiments of this invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units described above can be implemented in hardware or as software functional units. The above are merely embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for evaluating gait dynamic stability, characterized in that, It includes: The displacement and velocity of the human body's center of mass in the sagittal plane are obtained at each moment within a single support phase time period, wherein the single support phase time period is from the moment the toes leave the ground to the moment the heels touch the ground. The velocity stability region of the sagittal plane is calculated using the centroid displacement and the centroid velocity. Based on the velocity stability domain, a velocity stability domain curve is plotted, and the velocity stability domain curve is continuously differentiated to obtain the acceleration stability domain curve. The fluctuation degree of the acceleration stability domain curve is quantified, and gait stability is evaluated based on the quantified fluctuation degree. The more severe the fluctuation degree, the worse the gait stability of the human body; wherein: The velocity stability domain is based on the inverted pendulum model and is calculated using the centroid displacement and centroid velocity. The velocity stability domain curve is obtained by plotting the velocity stability domain at each moment within a single support phase time period; The process of quantifying the fluctuation degree of the acceleration stability domain curve and evaluating gait stability based on the quantified fluctuation degree, where more severe the fluctuation indicates poorer gait stability, includes: Based on the multifractal algorithm, the Shannon entropy of the acceleration stability domain is calculated using the acceleration stability domain curve. Gait stability is evaluated based on the acceleration stability domain Shannon entropy, and the larger the acceleration stability domain Shannon entropy, the worse the gait stability of the human body.

2. The gait dynamic stability evaluation method according to claim 1, characterized in that, The method for calculating the Shannon entropy of the acceleration stability domain using the acceleration stability domain curve based on the multifractal algorithm includes: The acceleration stability domain curve is coarsened to obtain a symbol sequence; The Shannon entropy of the acceleration stability region is calculated using the symbol sequence.

3. The gait dynamic stability evaluation method according to claim 2, characterized in that, The calculation process of the Shannon entropy in the acceleration stability region is expressed as follows: ； in, This represents the Shannon entropy of the acceleration stability region. These represent the individual sample points of the symbol sequence. Indicates sample The probability distribution of a random variable. Represents the weights of random variables, and .

4. The gait dynamic stability evaluation method according to claim 1, characterized in that, The calculation of the sagittal velocity stability domain using the centroid displacement and the centroid velocity includes: Obtain the toe point and heel point of the reference foot, and determine the foot length of the reference foot based on the toe point and heel point; The displacement and velocity of the center of mass are standardized using the reference leg length. The velocity stability region is calculated using the standardized centroid displacement and standardized centroid velocity.

5. The gait dynamic stability evaluation method according to claim 4, characterized in that, The velocity stability domain calculation process is expressed as follows: ； ； ； ； in, For standardization The displacement of the center of mass at time t, For standardization The velocity of the center of mass at any given moment. denoted as , where is the length from the center of mass in the sagittal plane to the ankle, and g is the acceleration due to gravity. Referring to the toe point, Referring to the heel point, The reference is of full length. for The displacement of the center of mass at time t, for The velocity of the center of mass at any given moment.

6. A gait dynamic stability evaluation device for implementing the gait dynamic stability evaluation method of claim 1, characterized in that, It includes: The acquisition module is used to acquire the displacement and velocity of the human body's center of mass in the sagittal plane at each moment within a single support phase time period, wherein the single support phase time period is from the moment the toes leave the ground to the moment the heels touch the ground. The calculation module is used to calculate the velocity stability domain of the sagittal plane using the centroid displacement and the centroid velocity; The plotting module is used to plot the velocity stability domain curve based on the velocity stability domain, and to continuously differentiate the velocity stability domain curve to obtain the acceleration stability domain curve. The evaluation module is used to quantify the fluctuation degree of the acceleration stability domain curve and evaluate gait stability based on the quantified fluctuation degree. The more severe the fluctuation degree, the worse the gait stability of the human body.

7. A computer device, characterized in that, The computer device includes a processor and a memory coupled to the processor, the memory storing program instructions that, when executed by the processor, cause the processor to perform the steps of the gait dynamic stability evaluation method as described in any one of claims 1-5.

8. A storage medium, characterized in that, The system stores program instructions capable of implementing the gait dynamic stability evaluation method as described in any one of claims 1-5.

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