Gait dynamic stability evaluation method, device and equipment and storage medium

Abstract

This invention discloses a method, apparatus, device, and storage medium for evaluating the dynamic stability of walking gait. The method involves acquiring the displacement and velocity of the human body's center of mass in the sagittal, coronal, and three-dimensional planes at various moments within a single support phase. Then, using the displacement and velocity, the velocity stability domains in the sagittal, coronal, and three-dimensional planes within the single support phase are calculated, and a standard curve is identified. Based on these velocity stability domains, a velocity stability domain curve for the single support phase is plotted. The similarity between the velocity stability domain curve and the standard curve is then calculated. Finally, the curve similarity is used to evaluate the gait stability of the human body; a higher similarity indicates poorer gait stability. This invention evaluates gait stability by comprehensively analyzing the similarity between the stability domain curves in the sagittal, coronal, and three-dimensional planes within a single support phase and the standard curve, resulting in more accurate analysis results.

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 the dynamic stability of walking gait. 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 the dynamic stability of walking gait, 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 solve the above-mentioned technical problems, one technical solution adopted in this application is: providing a method for evaluating the dynamic stability of walking gait, which includes: acquiring the first centroid displacement and first centroid velocity in the sagittal plane, the second centroid displacement and second centroid velocity in the coronal plane, and the third centroid displacement and third centroid velocity in three-dimensional space 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; based on an inverted pendulum model, calculating the first velocity stability domain in the sagittal plane using the first centroid displacement and first centroid velocity and confirming the first standard curve, calculating the second velocity stability domain in the coronal plane using the second centroid displacement and second centroid velocity and confirming the second standard curve, and using the first centroid displacement and second centroid velocity... The third velocity stability domain in three-dimensional space is calculated using the displacement of the first center of mass, the velocity of the second center of mass, the displacement of the third center of mass, and the velocity of the third center of mass, and the third standard curve is confirmed. Based on the first velocity stability domain, the second velocity stability domain curve, and the third velocity stability domain curve, the first velocity stability domain curve and the first standard curve are plotted. The first curve similarity between the first velocity stability domain curve and the first standard curve is calculated, the second curve similarity between the second velocity stability domain curve and the second standard curve is calculated, and the third curve similarity between the third velocity stability domain curve and the third standard curve is calculated. Gait stability is evaluated based on the similarity of the first curve, the second curve, and the third curve. The greater the curve similarity, the worse the gait stability of the human body.

[0007] As a further improvement of this application, the first velocity stability domain in the sagittal plane is calculated using the first centroid displacement and the first centroid velocity, including: obtaining the toe point and heel point of the reference foot, and determining the foot length of the reference foot based on the toe point and heel point; standardizing the first centroid displacement and the first centroid velocity using the foot length of the reference foot; and calculating the first velocity stability domain using the standardized first centroid displacement and the standardized first centroid velocity. The calculation process of the first velocity stability domain is expressed as follows:

[0008]

[0009]

[0010]

[0011] l fx =x1-x2;

[0012] in, This represents the first centroid displacement at time t after standardization. Let l be the standardized velocity of the first centroid 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 first centroid displacement at time t. Let be the velocity of the first center of mass at time t.

[0013] As a further improvement of this application, the second velocity stability domain of the coronal plane is calculated using the second centroid displacement and the second centroid velocity, including: confirming the coronal plane stability boundary based on the envelope method; standardizing the second centroid displacement and the second centroid velocity using the coronal plane stability boundary; and calculating the second velocity stability domain using the standardized second centroid displacement and the standardized second centroid velocity. The calculation process of the second velocity stability domain is expressed as follows:

[0014]

[0015]

[0016]

[0017] l fy =y Pro -y Dis ;

[0018] in, This represents the standardized displacement of the second centroid at time t. Let l be the standardized velocity of the second center of mass at time t. yThe length from the center of mass in the coronal plane to the ankle, g is the acceleration due to gravity, and y Pro y Dis For the boundary value of the coronal plane stability boundary, l fy For the coronal stable boundary, Y t Let be the displacement of the second centroid at time t. Let be the velocity of the second center of mass at time t.

[0019] As a further improvement of this application, the coronal plane stability boundary is confirmed based on the envelope method, including: obtaining a plantar pressure map of a reference foot and extracting the plantar pressure envelope from the plantar pressure map; constructing a plane rectangular coordinate system with the sagittal plane direction as the abscissa and the coronal plane direction as the ordinate axis, and mapping the plantar pressure envelope to the plane rectangular coordinate system; defining the projection line segment of the plantar pressure envelope in the coronal plane direction as the coronal plane stability boundary.

[0020] As a further improvement of this application, a third velocity stability domain in three-dimensional space is calculated using the first centroid displacement, second centroid displacement, first centroid velocity, second centroid velocity, third centroid displacement, and third centroid velocity. This includes: confirming the three-dimensional stability boundary based on the envelope method; standardizing the third centroid displacement and third centroid velocity using the three-dimensional stability boundary; and calculating the third velocity stability domain using the standardized third centroid displacement and standardized third centroid velocity. The calculation process of the third velocity stability domain is expressed as follows:

[0021]

[0022]

[0023]

[0024] l fxy =BOS max -BOS min ;

[0025] in, The displacement of the third centroid at time t is the standardized value. Let l be the standardized velocity of the third centroid at time t. xy The distance from the center of mass to the ankle in three-dimensional space is given by g, where g is the acceleration due to gravity, and BOS is the distance from the center of mass to the ankle. min BOS max Boundary values ​​of a three-dimensional stable boundary, l fxy For a three-dimensional stable boundary, XY t Let be the displacement of the third centroid at time t. Let be the velocity of the third center of mass at time t.

[0026] As a further improvement of this application, the three-dimensional stable boundary is confirmed based on the envelope method, including: obtaining a plantar pressure map of a reference foot and extracting the plantar pressure envelope from the plantar pressure map; constructing a two-dimensional plane based on the sagittal and coronal directions and mapping the plantar pressure envelope and the human body's center of mass to the two-dimensional plane; defining the region between the two intersection points of the extension of the human body's center of mass in the current center of mass velocity direction and the plantar pressure envelope as the three-dimensional stable boundary.

[0027] As a further improvement of this application, the calculation of the first curve similarity between the first velocity stability domain curve and the first standard curve, the calculation of the second curve similarity between the second velocity stability domain curve and the second standard curve, and the calculation of the third curve similarity between the third velocity stability domain curve and the third standard curve include: calculating the first Fréchet distance between the first velocity stability domain curve and the first standard curve, the second Fréchet distance between the second velocity stability domain curve and the second standard curve, and the third Fréchet distance between the third velocity stability domain curve and the third standard curve, respectively; and using the first Fréchet distance as the first curve similarity, the second Fréchet distance as the second curve similarity, and the third Fréchet distance as the third curve similarity, respectively.

[0028] To solve the above-mentioned technical problems, another technical solution adopted in this application is: providing a walking gait dynamic stability assessment device, which includes: an acquisition module, used to acquire the first centroid displacement and first centroid velocity in the sagittal plane, the second centroid displacement and second centroid velocity in the coronal plane, and the third centroid displacement and third centroid velocity in three-dimensional space 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; and a stability domain calculation module, used to calculate the first velocity stability domain in the sagittal plane and confirm the first standard curve based on the inverted pendulum model using the first centroid displacement and first centroid velocity, calculate the second velocity stability domain in the coronal plane and confirm the second standard curve using the second centroid displacement and second centroid velocity, and calculate the second velocity stability domain in the coronal plane and confirm the second standard curve using the first centroid displacement and second centroid velocity. The system calculates the third velocity stability domain in three-dimensional space using the first, second, and third center-of-mass velocities and their displacements, and confirms the third standard curve. A plotting module plots the first, second, and third velocity stability domain curves based on these domains. A similarity calculation module calculates the first curve similarity between the first velocity stability domain curve and the first standard curve, the second curve similarity between the second velocity stability domain curve and the second standard curve, and the third curve similarity between the third velocity stability domain curve and the third standard curve. An evaluation module assesses gait stability based on the similarity of the first, second, and third curves; a higher curve similarity indicates poorer gait stability.

[0029] 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 walking gait dynamic stability evaluation method as described above.

[0030] 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 the walking gait dynamic stability evaluation method described above.

[0031] The beneficial effects of this application are as follows: The walking gait dynamic stability assessment method of this application obtains the displacement and velocity of the human body's center of mass in the sagittal, coronal, and three-dimensional spaces at various moments within a single support phase time period. Then, using the displacement and velocity, it calculates the velocity stability domains in the sagittal, coronal, and three-dimensional spaces at various moments within the single support phase time period and identifies the standard curve. Based on the velocity stability domains, it plots the velocity stability domain curves within the single support phase time period, calculates the curve similarity between the velocity stability domain curves and the standard curves, and finally uses the curve similarity to assess the gait stability of the human body. A higher curve similarity indicates greater gait stability. The worse the gait stability, the more it extends the time-based gait stability analysis to the entire single-stance phase, comprehensively analyzing gait stability within the single-stance phase. This achieves gait stability analysis in the time dimension. Furthermore, it constructs the stability domain curve for the single-stance phase using the velocity stability domain of the human body's center of mass in the sagittal, coronal, and three-dimensional spaces. The similarity between the stability domain curve and the standard curve is calculated, and the similarity is used to evaluate the stability of the gait within the single-stance 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 evaluation results is improved. Attached Figure Description

[0032] Figure 1 This is a flowchart illustrating a method for evaluating the dynamic stability of walking gait according to an embodiment of the present invention.

[0033] 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;

[0034] Figure 3 This is a schematic diagram of the sagittal inverted pendulum model according to an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the plantar pressure envelope diagram according to an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the coronal plane inverted pendulum model according to an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of calculating the three-dimensional stable boundary using the plantar pressure envelope method according to an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the velocity stability domain curve according to an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the functional modules of the walking gait dynamic stability evaluation device according to an embodiment of the present invention;

[0040] Figure 9 This is a schematic diagram of the structure of a computer device according to an embodiment of the present invention;

[0041] Figure 10 This is a schematic diagram of the structure of the storage medium according to an embodiment of the present invention. Detailed Implementation

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Figure 1 This is a flowchart illustrating the walking 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 method for evaluating the dynamic stability of walking gait includes the following steps:

[0046] Step S101: Obtain the first centroid displacement and first centroid velocity in the sagittal plane, the second centroid displacement and second centroid velocity in the coronal plane, and the third centroid displacement and third centroid velocity in three-dimensional space 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 heel touches the ground.

[0047] 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)".

[0048] 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 first, second, and third center-of-mass displacements in the sagittal, coronal, and three-dimensional spaces. The first, second, and third center-of-mass velocities are then calculated based on these displacements. The formula for calculating the center-of-mass velocity is as follows:

[0049]

[0050] 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 first, second, and third center of mass velocities in the sagittal, coronal, and three-dimensional spaces can be calculated.

[0051] Step S102: Based on the inverted pendulum model, calculate the first velocity stability domain in the sagittal plane using the first centroid displacement and the first centroid velocity, and confirm the first standard curve. Calculate the second velocity stability domain in the coronal plane using the second centroid displacement and the second centroid velocity, and confirm the second standard curve. Calculate the third velocity stability domain in three-dimensional space using the first centroid displacement, the second centroid displacement, the first centroid velocity, the second centroid velocity, the third centroid displacement, and the third centroid velocity, and confirm the third standard curve.

[0052] 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.

[0053] Furthermore, the step of calculating the first velocity stability domain in the sagittal plane using the first centroid displacement and the first centroid velocity specifically includes:

[0054] 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.

[0055] 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.

[0056] 2. Standardize the displacement and velocity of the first center of mass using the reference length.

[0057] 3. The first velocity stability region is calculated using the standardized first centroid displacement and the standardized first centroid velocity.

[0058] 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.

[0059] 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:

[0060] 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:

[0061] COMx( Figure 3 (x, i.e., the projection position of the human body's center of mass on the sagittal axis) and COP ( Figure 3 When 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:

[0062]

[0063] in, It is the linear acceleration of COM in the X-axis direction.

[0064] 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.

[0065] 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.

[0066] 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:

[0067]

[0068] 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:

[0069]

[0070] 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.

[0071] 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.

[0072] Based on the above verification process, the velocity stability domain at time TO is extended to the entire single-support phase time period. The first velocity stability domain is expressed as:

[0073]

[0074]

[0075] l fx =x1-x2;

[0076] Where t is a moment within the entire single-support phase time period. This represents the first centroid displacement at time t after standardization. Let l be the standardized velocity of the first centroid 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 first centroid displacement at time t. Let be the velocity of the first center of mass at time t.

[0077] Furthermore, the step of calculating the second velocity stability domain of the coronal plane using the second centroid displacement and the second centroid velocity specifically includes:

[0078] 1. Confirm the stable boundary of the coronal plane based on the envelope method.

[0079] Furthermore, the steps for confirming the stable boundaries of the coronal plane based on the envelope method specifically include:

[0080] 1.1 Obtain the plantar pressure map of the reference foot and extract the plantar pressure envelope from the plantar pressure map.

[0081] 1.2 Construct a Cartesian coordinate system with the sagittal plane as the abscissa and the coronal plane as the ordinate, and map the plantar pressure envelope to the Cartesian coordinate system.

[0082] 1.3 The projection segment of the plantar pressure envelope in the coronal plane is defined as the coronal plane stability boundary.

[0083] This embodiment uses the envelope method to solve for the foot width during human walking, using the foot width as the stable boundary of the coronal plane. Specifically, as shown... Figure 4 As shown, Figure 4 This is a schematic diagram of the plantar pressure envelope, where the X-axis is the sagittal axis (AP) and the Y-axis is the coronal axis (ML). Figure 4 (a) shows the plantar pressure distribution map based on static standing posture, selecting the plantar pressure envelope; Figure 4 (b) shows the approximation method, where the two intersecting dashed lines represent the foot length and foot width, respectively. Point a is the first metatarsophalangeal joint, i.e., 72.5%. fx Location point; point b is the fifth metatarsophalangeal joint, i.e., 63.5% l fx The location point, and line segment ab, represent the coronal stability boundary defined by the approximation method. Figure 4 (c) shows that, based on the plantar pressure envelope method, the coronal stability boundary is defined as the maximum projection distance of the plantar pressure envelope line onto the coronal axis. The toe and heel are extracted from the plantar pressure envelope line and matched with the three-dimensional spatial positions of the toe and heel at time TO. After fitting the marked points, the projection line segment of the envelope line in the ML direction is defined as the coronal stability boundary.

[0084] 2. The displacement and velocity of the second centroid are standardized using the coronal stable boundary.

[0085] 3. The second velocity stability region is calculated using the standardized second centroid displacement and the standardized second centroid velocity.

[0086] Specifically, please refer to Figure 5 , Figure 5 This diagram illustrates an inverted coronal pendulum model, where the Z-axis is the vertical axis, the Y-axis is the horizontal (ML) coronal axis, COM is the body's center of mass, m is the mass, g is the acceleration due to gravity, ly is the distance from COM to the ankle on the coronal plane, and u... min and u max These are the minimum values ​​of the support surface on the Y-axis (y Dis ) and maximum value (y) Pro u is the instantaneous point of application of the center of plantar pressure (COP). (a), (b), and (c) are the three cases of COM and COP on the inner, lateral, and lateral sides of the ankle, respectively.

[0087] Based on the sagittal gait stability analysis, and considering the case where the relative velocities of COM and BOS are not considered, the applicability of the inverted pendulum model in the coronal plane is analyzed, and a coronal static stability mechanical model is proposed.

[0088] like Figure 5 As shown, the expression for angular momentum based on Newton's second law is:

[0089] ∑M=Iα;

[0090] Where I is the moment of inertia, I = mr 2 , m is the mass, and r is the vertical distance from COM to the pivot (ankle) (l) y ), It is the linear acceleration of COM in the Y-axis direction, because α and These are the angular and linear accelerations of COM relative to the ankle, so we have

[0091] Similar to the sagittal plane, the coronal plane also applies the angular momentum expression of Newton's second law to analyze the applicability of the inverted pendulum model in the coronal plane. It can be concluded that the inverted pendulum model is applicable in the coronal plane, and the calculation formula for the velocity stability domain of the coronal plane is derived. The calculation process for the second velocity stability domain is expressed as follows:

[0092]

[0093]

[0094]

[0095] l fy =y Pro -y Dis ;

[0096] in, This represents the standardized displacement of the second centroid at time t. Let l be the standardized velocity of the second center of mass at time t. y The length from the center of mass in the coronal plane to the ankle, g is the acceleration due to gravity, and y Pro y Dis For the boundary value of the coronal plane stability boundary, l fy For the coronal stable boundary, Y t Let be the displacement of the second centroid at time t. Let be the velocity of the second center of mass at time t.

[0097] Furthermore, the steps for calculating the third velocity stability domain in three-dimensional space using the first centroid displacement, second centroid displacement, first centroid velocity, second centroid velocity, third centroid displacement, and third centroid velocity specifically include:

[0098] 1. Confirmation of three-dimensional stable boundaries based on the envelope method.

[0099] Furthermore, the steps for confirming the stable boundaries of the coronal plane based on the envelope method specifically include:

[0100] 1.1 Obtain the plantar pressure map of the reference foot and extract the plantar pressure envelope from the plantar pressure map.

[0101] Specifically, a pressure map of the plantar pressure of the reference foot during single-leg standing support can be collected using a pressure sensor.

[0102] 1.2 Construct a two-dimensional plane based on the sagittal and coronal directions, and map the plantar pressure envelope and the human body's center of mass onto the two-dimensional plane.

[0103] 1.3. The region between the two intersection points of the extension of the human body's center of mass in the current velocity direction and the foot pressure envelope is defined as the three-dimensional stable boundary.

[0104] Specifically, such as Figure 6 As shown, in this embodiment, the three-dimensional space is defined as features in both the sagittal and coronal planes. The three-dimensional stable boundary is defined as the boundary between the planar region reachable by the COP and the current centroid velocity direction. It is approximately the line connecting the two intersection points of the extension line in the current centroid velocity direction and the plantar pressure envelope. This line region is the three-dimensional stable boundary region.

[0105] 2. The displacement and velocity of the third centroid are standardized using a three-dimensional stable boundary.

[0106] 3. The third velocity stability region is calculated using the standardized third centroid displacement and the standardized third centroid velocity.

[0107] Specifically, similar to the coronal dynamic stability analysis, the calculation method for the velocity stability domain in three-dimensional space can also be derived based on Newton's second law. The calculation process for the third velocity stability domain is expressed as follows:

[0108]

[0109]

[0110]

[0111] l fxy =BOS max -BOS min ;

[0112] in, The displacement of the third centroid at time t is the standardized value. Let l be the standardized velocity of the third centroid at time t. xy The distance from the center of mass to the ankle in three-dimensional space is given by g, where g is the acceleration due to gravity, and BOS is the distance from the center of mass to the ankle. minBOS max Boundary values ​​of a three-dimensional stable boundary, l fxy For a three-dimensional stable boundary, XY t Let be the displacement of the third centroid at time t. Let be the velocity of the third center of mass at time t.

[0113] For the sagittal plane, and As the boundary of the first velocity stability region, with As the first standard curve. For the coronal plane, and As the boundary of the second velocity stability region, with As a second standard curve. For three-dimensional space, and As the boundary of the third velocity stability region, with As the third standard curve.

[0114] Step S103: Draw the curves of the first velocity stability domain, the second velocity stability domain, and the third velocity stability domain based on the first velocity stability domain, the second velocity stability domain, and the third velocity stability domain.

[0115] 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 7 As shown, a coordinate system is constructed with the standardized centroid displacement as the abscissa and the standardized centroid velocity as the ordinate. The centroid displacement and centroid velocity corresponding to each moment are used as coordinate points, and the velocity stability domain curve is plotted on the coordinate system.

[0116] Step S104: Calculate the first curve similarity between the first velocity stability domain curve and the first standard curve; calculate the second curve similarity between the second velocity stability domain curve and the second standard curve; calculate the third curve similarity between the third velocity stability domain curve and the third standard curve.

[0117] Specifically, after plotting the velocity stability domain curve, the similarity between the velocity stability domain curve and the standard curve is calculated, and the stability of human gait is evaluated by the curve similarity.

[0118] Furthermore, step S104 specifically includes:

[0119] 1. Calculate the first Fréchet distance between the first velocity stability domain curve and the first standard curve, the second Fréchet distance between the second velocity stability domain curve and the second standard curve, and the third Fréchet distance between the third velocity stability domain curve and the third standard curve.

[0120] 2. The first Fraser distance is used as the first curve similarity, the second Fraser distance is used as the second curve similarity, and the third Fraser distance is used as the third curve similarity.

[0121] It should be noted that the curve similarity problem belongs to the field of curve matching. Trajectory similarity can be basically divided into three categories: point-based distance, shape-based distance, and segment-based distance. Point-based distance can be implemented using methods such as Euclidean distance, dynamic time normalization, longest common substring, and edit distance. Shape-based distance generally uses Hausdorff distance or Fraser distance. Segment-based distance involves unidirectional distance and multi-line position distance. In this embodiment, the velocity stability domain curve similarity problem within a single support phase time period falls under the shape-based distance category. Hausdorff distance is the maximum distance between the closest points of two trajectories. However, since the Hausdorff distance method emphasizes static relative position changes, it is not suitable for analyzing the temporal dynamic stability domain parameters within a single support phase. The Fraser distance method is more efficient for evaluating the similarity of curves with a certain spatial-temporal sequence. Therefore, this embodiment intends to apply this method for velocity stability domain curve similarity analysis. Its basic principle is to calculate the difference between the velocity stability domain curve and the standard curve; the larger the value, the worse the dynamic stability of the gait.

[0122] Specifically, in this embodiment, as Figure 7 As shown, the calculation process for the Fraser distance is as follows:

[0123] Let the standard curve be L1 and the velocity stability domain curve be L2. L1 has M sampling points and L2 has N sampling points. The distance between any two points is represented by the Euclidean distance.

[0124]

[0125] in: (x m ,y m (x) represents the sampling point on L1. n ,y n ) represents the sampling point on L2.

[0126] The maximum distance is d max =max(D), initializing the minimum distance: d min =min(D)=f, the loop interval is set to Set the values ​​in the distance D that are less than or equal to f to 1, and the values ​​that are greater than f to 0, to obtain a 0-1 matrix D′:

[0127]

[0128] Defined with d′ 11 Starting from d′ MNThe path R with the end point, the path R can only be in the right d′ m(n+1) , down d′ (m+1)n , bottom - right d′ (m+1)(n+1) Three directions to choose from. R = {d′ 11 , ……, d′ mn , …… d′ MN} always satisfies d′ 11 ·d′ mn ·d′ (m+k)(n+k′) …d′ MN = 1, where k ∈ [0, 1], k′ ∈ [0, 1]. When R does not exist, it means that the initial minimum distance is set too large. At this time, f = f + r, and loop依次 until a path that satisfies R is found. R is the Fréchet distance.

[0129] Calculate the first Fréchet distance corresponding to the first velocity stability region curve, the second Fréchet distance corresponding to the second velocity stability region curve, and the third Fréchet distance corresponding to the third velocity stability region curve based on the above Fréchet distance calculation method. Then, take the first Fréchet distance, the second Fréchet distance, and the third Fréchet distance as the first curve similarity, the second curve similarity, and the third curve similarity respectively.

[0130] Step S105: Evaluate the gait stability based on the first curve similarity, the second curve similarity, and the third curve similarity. The greater the curve similarity, the worse the gait stability of the human body.

[0131] Specifically, the greater the curve similarity, the worse the gait stability of the human body.

[0132] The walking gait dynamic stability evaluation method of this embodiment obtains the centroid displacement and centroid velocity of the human body's center of mass at each moment in the sagittal plane, coronal plane, and three - dimensional space during the single - support phase. Then, it calculates the velocity stability regions in the sagittal plane, coronal plane, and three - dimensional space at each moment during the single - support phase using the centroid displacement and centroid velocity and determines the standard curve, and then draws the velocity stability region curve during the single - support phase based on the velocity stability region. Next, it calculates the curve similarity between the velocity stability region curve and the standard curve. Finally, it uses the curve similarity to evaluate the gait stability of the human body. The greater the curve similarity, the worse the gait stability of the human body. It extends the gait stability analysis based on moments to the entire single - support phase to comprehensively analyze the gait stability within the single - support phase, thereby realizing gait stability analysis in the time dimension. Moreover, it constructs the stability region curve of the single - support phase using the velocity stability regions of the human body's center of mass in the sagittal plane, coronal plane, and three - dimensional space, calculates the similarity between the stability region curve and the standard curve, and uses the similarity to evaluate the stability of the gait within the single - support phase, thereby realizing gait stability analysis in the spatial dimension. By comprehensively analyzing gait stability in the time dimension and spatial dimension, the accuracy of the evaluation results is improved.

[0133] Figure 8 This is a schematic diagram of the functional modules of the walking gait dynamic stability evaluation device according to an embodiment of the present invention. Figure 8 As shown, the walking gait dynamic stability evaluation device 20 includes an acquisition module 21, a stability domain calculation module 22, a drawing module 23, a similarity calculation module 24, and an evaluation module 25.

[0134] The acquisition module 21 is used to acquire the first centroid displacement and first centroid velocity in the sagittal plane, the second centroid displacement and second centroid velocity in the coronal plane, and the third centroid displacement and third centroid velocity in three-dimensional space at each moment during 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.

[0135] The stability domain calculation module 22 is used to calculate the first velocity stability domain in the sagittal plane and confirm the first standard curve based on the inverted pendulum model using the first centroid displacement and the first centroid velocity; to calculate the second velocity stability domain in the coronal plane and confirm the second standard curve using the second centroid displacement and the second centroid velocity; and to calculate the third velocity stability domain in the three-dimensional space and confirm the third standard curve using the first centroid displacement, the second centroid displacement, the first centroid velocity, the second centroid velocity, the third centroid displacement, and the third centroid velocity.

[0136] The drawing module 23 is used to draw the first velocity stability domain curve, the second velocity stability domain curve, and the third velocity stability domain curve based on the first velocity stability domain, the second velocity stability domain, and the third velocity stability domain.

[0137] The similarity calculation module 24 is used to calculate the first curve similarity between the first velocity stability domain curve and the first standard curve, calculate the second curve similarity between the second velocity stability domain curve and the second standard curve, and calculate the third curve similarity between the third velocity stability domain curve and the third standard curve.

[0138] Evaluation module 25 is used to evaluate gait stability based on the first curve similarity, the second curve similarity, and the third curve similarity. The greater the curve similarity, the worse the gait stability of the human body.

[0139] Optionally, the stability domain calculation module 22 performs the operation of calculating the first velocity stability domain in the sagittal plane using the first centroid displacement and the first centroid velocity, specifically including:

[0140] Obtain the toe and heel points of the reference foot, and determine the foot length of the reference foot based on the toe and heel points;

[0141] The displacement and velocity of the first center of mass are standardized using the reference length.

[0142] The first velocity stability region is calculated using the standardized first centroid displacement and the standardized first centroid velocity. The calculation process for the first velocity stability region is as follows:

[0143]

[0144]

[0145]

[0146] l fx =x1-x2;

[0147] in, This represents the first centroid displacement at time t after standardization. Let l be the standardized velocity of the first centroid 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 first centroid displacement at time t. Let be the velocity of the first center of mass at time t.

[0148] Optionally, the stability domain calculation module 22 performs the operation of calculating the second velocity stability domain of the coronal plane using the second centroid displacement and the second centroid velocity, specifically including:

[0149] Confirmation of stable boundaries in the coronal plane based on the envelope method;

[0150] The displacement and velocity of the second centroid are standardized using the coronal plane stable boundary.

[0151] The second velocity stability region is calculated using the standardized displacement and velocity of the second centroid. The calculation process for the second velocity stability region is as follows:

[0152]

[0153]

[0154]

[0155] l fy =y Pro -y Dis ;

[0156] in, This represents the standardized displacement of the second centroid at time t. Let l be the standardized velocity of the second center of mass at time t. y The length from the center of mass in the coronal plane to the ankle, g is the acceleration due to gravity, and yPro y Dis For the boundary value of the coronal plane stability boundary, l fy For the coronal stable boundary, Y t Let be the displacement of the second centroid at time t. Let be the velocity of the second center of mass at time t.

[0157] Optionally, the stability domain calculation module 22 performs an operation to confirm the coronal stability boundary based on the envelope method, specifically including:

[0158] Obtain the plantar pressure map of the reference foot and extract the plantar pressure envelope from the plantar pressure map;

[0159] A Cartesian coordinate system was constructed with the sagittal plane as the abscissa and the coronal plane as the ordinate, and the plantar pressure envelope was mapped to the Cartesian coordinate system.

[0160] The projection segment of the plantar pressure envelope onto the coronal plane is defined as the coronal plane stability boundary.

[0161] Optionally, the stability domain calculation module 22 performs the operation of calculating the third velocity stability domain in three-dimensional space using the first centroid displacement, the second centroid displacement, the first centroid velocity, the second centroid velocity, the third centroid displacement, and the third centroid velocity, specifically including:

[0162] Three-dimensional stable boundaries were identified based on the envelope method.

[0163] The displacement and velocity of the third centroid are standardized using a three-dimensional stable boundary.

[0164] The third velocity stability region is calculated using the standardized third centroid displacement and the standardized third centroid velocity. The calculation process for the third velocity stability region is as follows:

[0165]

[0166]

[0167]

[0168] l fxy =BOS max -BOS min ;

[0169] in, The displacement of the third centroid at time t is the standardized value. Let l be the standardized velocity of the third centroid at time t. xy The distance from the center of mass to the ankle in three-dimensional space is given by g, where g is the acceleration due to gravity, and BOS is the distance from the center of mass to the ankle. min BOS maxBoundary values ​​of a three-dimensional stable boundary, l fxy For a three-dimensional stable boundary, XY t Let be the displacement of the third centroid at time t. Let be the velocity of the third center of mass at time t.

[0170] Optionally, the stability domain calculation module 22 performs an operation to confirm the three-dimensional stability boundary based on the envelope method, specifically including:

[0171] Obtain the plantar pressure map of the reference foot and extract the plantar pressure envelope from the plantar pressure map;

[0172] A two-dimensional plane is constructed based on the sagittal and coronal directions, and the plantar pressure envelope and the human body's center of mass are mapped onto the two-dimensional plane;

[0173] The region between the two intersection points of the extension of the human body's center of mass in the current velocity direction and the foot pressure envelope is defined as the three-dimensional stable boundary.

[0174] Optionally, the similarity calculation module 24 performs operations to calculate the first curve similarity between the first velocity stability domain curve and the first standard curve, to calculate the second curve similarity between the second velocity stability domain curve and the second standard curve, and to calculate the third curve similarity between the third velocity stability domain curve and the third standard curve. Specifically, this includes:

[0175] Calculate the first Fréchet distance between the first velocity stability domain curve and the first standard curve, the second Fréchet distance between the second velocity stability domain curve and the second standard curve, and the third Fréchet distance between the third velocity stability domain curve and the third standard curve, respectively.

[0176] The first Frescher distance is used as the first curve similarity, the second Frescher distance is used as the second curve similarity, and the third Frescher distance is used as the third curve similarity.

[0177] For other details regarding the implementation of the technical solutions for each module in the walking gait dynamic stability evaluation device in the above embodiments, please refer to the description in the walking gait dynamic stability evaluation method in the above embodiments, which will not be repeated here.

[0178] 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.

[0179] Please see Figure 9 , Figure 9 This is a schematic diagram of the structure of a computer device according to an embodiment of the present invention. Figure 9 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 walking gait dynamic stability evaluation method described in any of the above embodiments.

[0180] 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.

[0181] See Figure 10 , Figure 10 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 walking 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.

[0182] 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, or indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0183] 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 the dynamic stability of walking gait, characterized in that, It includes: The first displacement and velocity of the human body's center of mass in the sagittal plane, the second displacement and velocity of the center of mass in the coronal plane, and the third displacement and velocity of the center of mass in three-dimensional space are obtained at each moment within a single support phase time period. The single support phase time period is from the moment the toes leave the ground to the moment the heel touches the ground. Based on the inverted pendulum model, the first velocity stability domain in the sagittal plane is calculated using the first centroid displacement and the first centroid velocity, and the first standard curve is confirmed. The second velocity stability domain in the coronal plane is calculated using the second centroid displacement and the second centroid velocity, and the second standard curve is confirmed. The third velocity stability domain in the three-dimensional space is calculated using the first centroid displacement, the second centroid displacement, the first centroid velocity, the second centroid velocity, the third centroid displacement, and the third centroid velocity, and the third standard curve is confirmed. Based on the first velocity stability domain, the second velocity stability domain, and the third velocity stability domain, plot the first velocity stability domain curve, the second velocity stability domain curve, and the third velocity stability domain curve; Calculate the first curve similarity between the first velocity stability domain curve and the first standard curve, calculate the second curve similarity between the second velocity stability domain curve and the second standard curve, and calculate the third curve similarity between the third velocity stability domain curve and the third standard curve. Gait stability is evaluated based on the first curve similarity, the second curve similarity, and the third curve similarity. The greater the curve similarity, the worse the gait stability of the human body. The calculation of the first velocity stability domain in the sagittal plane using the first centroid displacement and the first 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 first centroid are standardized using the reference leg length. The first velocity stability region is calculated using the standardized first centroid displacement and the standardized first centroid velocity. The calculation process for the first velocity stability region is as follows: ； ； ； ； in, For standardization The first displacement of the center of mass at time t, For standardization The first center of mass velocity 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 first displacement of the center of mass at time t, for The velocity of the first center of mass at any given moment; The calculation of the second velocity stability domain of the coronal plane using the second centroid displacement and the second centroid velocity includes: Confirmation of stable boundaries in the coronal plane based on the envelope method; The displacement and velocity of the second centroid are standardized using the coronal plane stability boundary. The second velocity stability region is calculated using the standardized second centroid displacement and the standardized second centroid velocity. The calculation process for the second velocity stability region is as follows: ； ； ； = - ； in, For standardization The second displacement of the center of mass at time t, For standardization The second center-of-mass velocity at time t. denoted as , where is the length from the center of mass in the coronal plane to the ankle, and g is the acceleration due to gravity. , The boundary value of the coronal plane stability boundary. This is the stable boundary of the coronal plane. for The second displacement of the center of mass at time t, for The second center-of-mass velocity at that moment; The calculation of the third velocity stability domain in three-dimensional space using the first centroid displacement, the second centroid displacement, the first centroid velocity, the second centroid velocity, the third centroid displacement, and the third centroid velocity includes: Three-dimensional stable boundaries were identified based on the envelope method. The displacement and velocity of the third centroid are standardized using the three-dimensional stable boundary. The third velocity stability region is calculated using the standardized third centroid displacement and the standardized third centroid velocity. The calculation process for the third velocity stability region is as follows: ； ； ； ； in, For standardization The displacement of the third center of mass at time t. For standardization The velocity of the third center of mass at time t. Let g be the length from the center of mass to the ankle in three-dimensional space, and g be the acceleration due to gravity. , The boundary values ​​of the three-dimensional stable boundary, For the three-dimensional stable boundary, for The displacement of the third center of mass at time t. for The velocity of the third center of mass at that moment; The calculation of the first curve similarity between the first velocity stability domain curve and the first standard curve, the calculation of the second curve similarity between the second velocity stability domain curve and the second standard curve, and the calculation of the third curve similarity between the third velocity stability domain curve and the third standard curve include: Calculate the first Fréchet distance between the first velocity stability domain curve and the first standard curve, the second Fréchet distance between the second velocity stability domain curve and the second standard curve, and the third Fréchet distance between the third velocity stability domain curve and the third standard curve, respectively. The first Fraser distance is used as the first curve similarity, the second Fraser distance is used as the second curve similarity, and the third Fraser distance is used as the third curve similarity.

2. The method for evaluating the dynamic stability of walking gait according to claim 1, characterized in that, The method of confirming the stable boundary of the coronal plane based on the envelope method includes: Obtain the plantar pressure map of the reference foot, and extract the plantar pressure envelope from the plantar pressure map; A Cartesian coordinate system is constructed with the sagittal plane direction as the abscissa and the coronal plane direction as the ordinate, and the plantar pressure envelope is mapped to the Cartesian coordinate system. The projection segment of the plantar pressure envelope in the coronal plane is defined as the coronal plane stability boundary.

3. The method for evaluating the dynamic stability of walking gait according to claim 2, characterized in that, The method of confirming three-dimensional stable boundaries based on the envelope method includes: Obtain the plantar pressure map of the reference foot, and extract the plantar pressure envelope from the plantar pressure map; A two-dimensional plane is constructed based on the sagittal plane and the coronal plane, and the plantar pressure envelope and the human body's center of mass are mapped onto the two-dimensional plane; The region between the two intersection points of the extension of the human body's center of mass in the current center of mass velocity direction and the foot pressure envelope is defined as the three-dimensional stable boundary.

4. A walking gait dynamic stability assessment device utilizing the walking gait dynamic stability assessment method of claim 1, characterized in that, It includes: The acquisition module is used to acquire the first centroid displacement and first centroid velocity in the sagittal plane, the second centroid displacement and second centroid velocity in the coronal plane, and the third centroid displacement and third centroid velocity in three-dimensional space at each moment within a 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. The stability domain calculation module is used to calculate the first velocity stability domain in the sagittal plane and confirm the first standard curve based on the inverted pendulum model using the first centroid displacement and the first centroid velocity; calculate the second velocity stability domain in the coronal plane and confirm the second standard curve using the second centroid displacement and the second centroid velocity; and calculate the third velocity stability domain in three-dimensional space and confirm the third standard curve using the first centroid displacement, the second centroid displacement, the first centroid velocity, the second centroid velocity, the third centroid displacement, and the third centroid velocity. The plotting module is used to plot the first velocity stability domain curve, the second velocity stability domain curve, and the third velocity stability domain curve based on the first velocity stability domain, the second velocity stability domain, and the third velocity stability domain. The similarity calculation module is used to calculate the first curve similarity between the first velocity stability domain curve and the first standard curve, calculate the second curve similarity between the second velocity stability domain curve and the second standard curve, and calculate the third curve similarity between the third velocity stability domain curve and the third standard curve. The evaluation module is used to evaluate gait stability based on the first curve similarity, the second curve similarity, and the third curve similarity. The greater the curve similarity, the worse the gait stability of the human body.

5. 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 walking gait dynamic stability evaluation method as described in any one of claims 1-3.

6. A storage medium, characterized in that, The system stores program instructions capable of implementing the walking gait dynamic stability evaluation method as described in any one of claims 1-3.

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