A high-biomimetic digital human body model lower limb impact verification method

Abstract

The present application relates to the technical fields of digital human model verification test, and discloses a high-biomimetic digital human model lower limb impact verification method, a collision simulation environment is constructed based on biomechanical response data, and a digital human model is positioned to a target impact position; through force analysis of a seat contact surface, a reaction force loading mechanism is established to simulate the interaction between human gravity and the seat; during the loading process, fixed constraints are applied to key skeletal parts, a retractable beam unit is used to drive joint posture adjustment, one end of the beam unit is bound to the skeleton, and the other end is fixed to the target position, the skeleton binding point is pulled to move to the target position by using unit contraction, and the movement of the skeleton and soft tissue is driven, so that accurate adjustment of the joint posture is realized; finally, multiple working conditions are fused, the activation and failure of each working condition are controlled through time series, and lower limb impact simulation verification is completed. The physiological posture and mechanical state before impact are effectively restored, and the model biomimetic degree and verification accuracy are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of digital human model verification test, and particularly relates to a high-biomimetic digital human model lower limb impact verification method. BACKGROUND

[0002] In the field of automobile collision safety analysis and biomechanics simulation, digital human models have gradually replaced traditional physical dummies and become key tools for human injury mechanism research, and ensuring the biomimetic fidelity of digital human models is a key prerequisite for verifying their effectiveness. At present, the most important method for verifying the biomimetic degree of digital human models is to compare and verify with high-precision biomechanics experimental data. However, the existing verification methods still have significant limitations in the biomimetic restoration degree when building experimental verification conditions, mainly showing two types of technical defects: one is to directly apply impact load to the target verification position of the digital human model, but ignoring the biomechanics influence of the joint angle of the human body at the impact moment; the other is to adjust the joint angle, but does not consider the distortion of the initial strain distribution of the mesh caused by the posture adjustment, and does not couple the interaction mechanism of the human body gravity and the seat. The above defects make it difficult for the existing method to accurately reproduce the biomechanics response of the biomechanics experiment.

[0003] Therefore, there is an urgent need for a high-biomimetic digital human model lower limb impact verification method, which makes the initial biomechanics state of the digital human model at the impact moment highly consistent with the biomechanics response data, thereby significantly improving the reliability and accuracy of the verification results. SUMMARY

[0004] To solve the above technical problems, the present application provides a high-biomimetic digital human model lower limb impact verification method, which makes the initial biomechanics state of the digital human model at the impact moment highly consistent with the biomechanics response data, thereby significantly improving the reliability and accuracy of the verification results.

[0005] The present application provides a high-biomimetic digital human model lower limb impact verification method, comprising the following steps:

[0006] Based on the biomechanics response data, a collision simulation environment is built, including an impact hammer model and a rigid seat model;

[0007] Position the digital human model to the target impact position;

[0008] Simulate the interaction of the gravity of the digital human model and the rigid seat model, and establish a counterforce loading mechanism based on the force analysis of the seat contact surface;

[0009] During the counterforce loading process, fixed constraints are applied to the key skeletal parts of the digital human model;

[0010] adjusting a joint posture of the digital human model to a target posture by a driving unit;

[0011] The working conditions of the reaction force loading, the fixed constraint applied to the key skeletal position, the target posture adjustment, the impact hammer hitting, and the gravity loading of the digital human model are activated and deactivated through time sequence control to complete the impact verification method for the lower limbs of the digital human model.

[0012] Further, the positioning of the digital human model to the target hitting position further comprises:

[0013] The distance between the hip contact surface of the digital human model and the seat contact surface is set to avoid physical penetration, and the distance is determined based on the sum of the outermost shell thickness of the digital human model and the seat thickness.

[0014] Further, the stress analysis comprises:

[0015] The thigh and the seat contact surface and the torso mass above the digital human model are measured, and the mass point of the geometric center of the seat contact surface is measured according to the seat mass and the thigh and the seat contact surface and the torso mass above the digital human model.

[0016] Further, the reaction force loading mechanism comprises:

[0017] An upward vertical force equivalent to gravity is applied to the seat.

[0018] Further, the key skeletal positions comprise: the pelvis, the ribs, and the spine.

[0019] Further, the driving unit is a fully retracted beam unit, the beam unit is bound to the skeleton through a first node, and a second node is fixed at a target position, the displacement of the skeleton and soft tissue is driven by the retraction movement of the beam unit, and the joint posture of the digital human model is adjusted to the target posture.

[0020] Further, the adjustment of the joint posture is for the lower limbs, comprising:

[0021] Femur angle adjustment: the first node is defined at the distal end of the femur, and the target position is determined based on the parallel relationship between the femur reference point connection line and the plane;

[0022] Calf angle adjustment: the first node is defined at the midpoint of the ankle, and the target position is determined based on the vertical relationship between the calf reference point connection line and the plane.

[0023] Further, the working conditions of the reaction force loading, the fixed constraint applied to the key skeletal position, the target posture adjustment, the impact hammer hitting, and the gravity loading of the digital human model are activated and deactivated through time sequence control, specifically comprising:

[0024] According to the biomechanical simulation requirements, the total time of the whole working condition is divided into: an initial time period and a subsequent time period;

[0025] The initial time period: maintain the reaction force loading, the key skeletal position fixed constraint application and the target posture adjustment working condition, wherein: the reaction force loading working condition is activated to simulate the extrusion effect of the seat on the digital human body model; the key skeletal position fixed constraint application working condition is activated to inhibit the displacement of the digital human body model; and the target posture adjustment working condition is activated to adjust the joint angle through the beam unit contraction driving.

[0026] The subsequent time period: release the key skeletal position fixed constraint application, and synchronously start the impact hammer impact and the digital human body model gravity loading working condition, wherein: the impact hammer impact working condition is activated to apply an acceleration load to the target part of the lower limb; and the digital human body model gravity loading working condition is activated to restore the effect of the human body gravity.

[0027] The present application has the following technical effects:

[0028] By building a collision simulation environment consistent with high-precision biomechanical experimental data, the standardization of the initial working condition is ensured; the digital human body model is positioned to the target impact position to avoid verification distortion caused by position deviation; a reaction force loading mechanism is established based on the force analysis of the seat contact surface to accurately simulate the interaction between the human body gravity and the seat and restore the real biomechanical load distribution; fixed constraints are applied during the reaction force loading process to effectively inhibit displacement deviation and provide a stable foundation for subsequent adjustment; the joint posture is adjusted to the target posture through the driving unit to dynamically generate an initial stress consistent with biological characteristics and eliminate the defects of traditional methods that ignore the initial strain; finally, multiple working conditions are fused and the activation and failure of each working condition are controlled through time sequence to realize seamless cooperation of static preloading and dynamic response, ensure that the stress transmission path at the impact moment and the biomechanical response data are highly consistent, and thus breakthrough improvement is realized in joint angle fidelity, initial stress distribution and gravity coupling accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0030] Figure 1 is a flowchart of a high-biomimetic digital human body model lower limb impact verification method provided by an embodiment of the present application;

[0031] Figure 2 is a schematic diagram of an impact hammer model and a rigid seat model provided by an embodiment of the present application;

[0032] Figure 3 is a schematic diagram of a positioned digital human body model provided by an embodiment of the present application;

[0033] Figure 4 is a schematic diagram of a thigh of a digital human body model and a seat contact surface and a mass point of a geometric center of an upper torso mass and a seat contact surface provided by an embodiment of the present application;

[0034] Figure 5 is a schematic diagram of femoral joint angle adjustment provided by an embodiment of the present application;

[0035] Figure 6 is a schematic diagram of calf joint angle adjustment provided by an embodiment of the present application;

[0036] Figure 7 is a schematic diagram of fusion multi-condition digital human body model lower limb impact verification provided by an embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0038] Figure 1 is a flowchart of a high-biomimetic digital human body model lower limb impact verification method provided by an embodiment of the present application. Referring to Figure 1 , specifically comprising:

[0039] S1, based on biomechanical response data, a collision simulation environment is built, including an impact hammer model and a rigid seat model.

[0040] When building the collision simulation environment, the standardization specifications for biomechanical response data are strictly followed to ensure that the virtual verification scenario is comparable to real biomechanical experiments. The biomechanical response data refers to experimentally obtained data that accurately reflects the mechanical response of the human body under impact. This data may include, but is not limited to, data obtained through post-mortem human body (PMHS) testing, animal experiments, or volunteer experiments (within safe limits). In a preferred embodiment of this invention, the data preferably originates from PMHS tests that adhere to strict testing specifications. This process uses finite element preprocessing software to construct two core models: an impact hammer model, which fully replicates the mass distribution and motion characteristics of the impact device in the PMHS test, configuring the same impact velocity curve to ensure that the kinetic energy transfer mechanism is consistent with the physical experiment; and a rigid seat model, which simplifies the seat into a rigid structure based on the stiffness difference between human tissue and seat material in the PMHS test, preserving the geometry and support characteristics of the contact interface while eliminating the interference of material deformation on the verification results.

[0041] In this embodiment, as Figure 2 As shown, a three-dimensional solid impact hammer was created using the geometric modeling function of finite element software and given the same inertial properties as the PMHS test equipment; the seat model was shielded from unnecessary deformation by defining a rigid body material. This design accurately reproduces the boundary conditions in the PMHS test while ensuring computational efficiency—simulating the dynamic behavior of the impact hammer to simulate real impact loads, while the rigid seat focuses on the interaction mechanism between the human body model and the support surface.

[0042] S2. Position the digital human body model to the target impact location.

[0043] Furthermore, S2 also includes: setting the distance between the buttock contact surface of the digital human body model and the seat contact surface to avoid physical penetration, wherein the distance is determined based on the sum of the thickness of the outermost shell of the digital human body model and the thickness of the seat.

[0044] The impact position and direction of the impact hammer are determined based on the PMHS test data, and a three-dimensional seat model consistent with the test is established in the virtual simulation environment. The digital human model is imported into the simulation system and is preliminarily positioned to be approximately in the sitting posture state in the test, and the posture of the trunk and lower limbs of the human model is adjusted by inverse kinematics or manually to be close to the initial posture recorded in the test. The overall displacement and rotation of the digital human model are further adjusted to align the expected impact area of the digital human model with the preset impact path of the impact hammer, and the projection position of the impact point on the human model is ensured to be within a preset range (generally controlled within ±10 mm) and the impact angle deviation is generally not more than ±5° by using a measuring tool. Physical penetration or virtual penetration due to the thickness of the shell between the human model and the seat is avoided, and the initial distance d between the contact surface of the buttocks of the digital human model and the contact surface of the seat is set to be the sum of half of the outermost shell thickness d1 of the digital human model and half of the seat thickness d2, that is, d = d1 / 2 + d2 / 2. In this way, the accurate posture matching of the digital human model is realized, the impact conditions are ensured to be highly consistent with the real vehicle or trolley test, the simulation result is prevented from being distorted due to initial penetration or posture deviation, the accuracy of the biomechanical response prediction is improved, and a reliable basis is provided for vehicle safety evaluation.

[0045] S3, simulate the interaction between the gravity of the digital human model and the rigid seat model, and establish a reaction force loading mechanism based on force analysis of the seat contact surface.

[0046] In some embodiments, the force analysis includes:

[0047] The mass of the thighs of the digital human model and the torso above the seat contact surface is measured, and the mass point of the geometric center of the seat contact surface is measured according to the mass of the seat and the mass of the thighs of the digital human model and the torso above the seat contact surface.

[0048] In some embodiments, in the S3, the reaction force loading mechanism includes:

[0049] An upward force equivalent to gravity is applied to the seat.

[0050] Specifically, after the positioning of the digital human model is completed, the force analysis of the seat contact surface and the reaction force loading are performed. First, the mass of the thighs of the digital human model and the torso above the seat contact surface is measured, denoted as m1, and the mass point m2 of the geometric center of the seat contact surface is measured according to the mass m3 of the seat and the mass m1 of the thighs of the digital human model and the torso above the seat contact surface, and the specific calculation formula is: m1 = m2 + m3, as shown in Figure 4The quality distribution of the seat system under static support condition is ensured to match the actual force condition. On this basis, the interaction between the digital human model gravity and the rigid seat model is simulated, and the reverse gravity is added to the seat with the mass point, the size of the force is equal to the gravity suffered by the digital human model thigh and the seat contact surface and the upper torso, and the direction is perpendicular to the seat surface upward. The force is used as the core of the counterforce loading mechanism to balance the compression of the human model on the seat in the static posture, ensure the reasonable distribution of the contact surface pressure, and avoid the sinking or unstable contact of the model due to unbalanced gravity. Through the counterforce loading mode, the stable initial contact state can be established without exciting the dynamic response, and the load distribution characteristics of the seat contact surface under the sitting posture of the human body are accurately reflected, so as to provide reliable initial mechanical boundary conditions for subsequent dynamic impact simulation.

[0051] The application restores the interaction relationship between the human body gravity and the seat through the seat stress analysis and the counterforce loading mechanism. The reverse force corresponding to the local mass of the human body is applied to the seat contact surface, the compression effect of the human body on the seat is simulated, the mechanical balance of the contact interface is ensured, the initial penetration or contact pressure distortion is effectively prevented, and the accuracy and stability of the contact force calculation are improved.

[0052] S4、In the counterforce loading process, fixed constraints are applied to the key skeletal parts of the digital human model.

[0053] In the counterforce loading process, in order to prevent the digital human model from producing non-physiological overall displacement or posture instability under the vertical counterforce applied by the seat, fixed constraints are applied to the key skeletal structures of the model. Specifically, the key skeletal parts include: the pelvis, the ribs and the spine.

[0054] The translational degrees of freedom (X, Y, Z directions) of the pelvic skeleton are completely fixed by the boundary condition setting function of the simulation software, which limits the overall movement of the pelvic skeleton in space; the rotational degrees of freedom (rotation around X, Y, Z axes) of the spine are constrained to prevent the trunk from swaying forward and backward or laterally twisting during the loading process; at the same time, slight lateral and forward and backward translational constraints are applied to the rib structure to maintain the stability of the chest shape and avoid distortion of the model due to uneven local stress. The above constraints only limit the rigid body displacement and non-physiological large deformation, ensuring that the digital human model can maintain a reasonable initial posture during the simulation of the seat being pressed upward, avoiding the influence of model sliding or overturning on the accuracy of contact force distribution and subsequent injury response. The fixed constraint is a temporary fixed constraint when the seat exerts gravity on key skeletal parts such as the pelvis, ribs and spine, effectively inhibiting non-physiological displacement or overall swaying of the model during preloading, ensuring the stability and controllability of posture reconstruction. The constraint is timely released before the start of dynamic impact, ensuring the reasonableness of the initial state and not hindering the natural evolution of subsequent free motion response.

[0055] S5, adjusting the joint posture of the digital human model to a target posture by a driving unit.

[0056] In some embodiments, in the S5, the driving unit is a fully contracted beam unit, the first node of which is bound to the skeleton, and the second node is fixed to a target position. The contraction movement of the beam unit drives the displacement of the skeleton and soft tissue, and adjusts the joint posture of the digital human model to the target posture.

[0057] In some embodiments, the adjustment of the joint posture is for the lower limbs, including:

[0058] Femur angle adjustment: the first node is defined at the distal end of the femur, and the target position is determined based on the parallel relationship between the femur reference point connection line and the plane;

[0059] Calf angle adjustment: the first node is defined at the midpoint of the ankle, and the target position is determined based on the vertical relationship between the calf reference point connection line and the plane.

[0060] In the embodiments of the present application, during the posture adjustment of the digital human model, a contraction type beam unit is used to drive the movement of the skeleton to achieve precise joint angle control. This method drives the movement of the skeleton node through the length change of the beam unit, and then pulls the connected soft tissue to achieve smooth adjustment of the overall posture.

[0061] Specifically, during femur joint angle adjustment, the target posture is first determined. For example, Figure 5As shown, the anatomical position of the distal femur is selected as the skeletal driving node (node 1), and its initial coordinates are (a1, b1, c1). Two angle reference points are set: the coordinates of angle reference point 1 are (X1, Y1, Z1), and the coordinates of angle reference point 2 are (X2, Y2, Z2), and Y1 = Y2 is satisfied to ensure that the line connecting the two points is at the same horizontal height. The target posture requires that the line connecting angle reference point 1 and angle reference point 2 is parallel to the XY plane, i.e., the line has no inclination in the Z-axis direction. According to this target, the target position to which node 1 should move is calculated, and another end node (node 2) of the beam element is set at this position, with coordinates (a2, b2, c2). To ensure the correct driving direction, the beam element is initially parallel to the XZ plane, i.e., its direction vector has no component in the Y-axis direction. Then, the beam element is defined as a fully contracted type, and its length is gradually shortened in the simulation step until it approaches zero. As the beam element contracts, node 1 moves towards node 2 under the action of the element tension and eventually coincides with it, thereby driving the femur to rotate around the hip joint to the target angle. In this process, the movement of the femur further pulls the soft tissues such as the hip muscles and fat to adjust synchronously, achieving a physiological sit-up reconstruction.

[0062] The coordinates of node 2 can be calculated from angle reference node 1, angle reference node 2, and node 1, and the calculation formula is:

[0063] .

[0064] When adjusting the angle of the lower leg joint, a similar method is used. As shown in Figure 6 , the driving node (node 3) is defined at the midpoint of the ankle, and its initial coordinates are (a3, b3, c3). Two anatomical points on the tibia are selected as angle reference points: the coordinates of angle reference point 3 are (X3, Y3, Z3), and the coordinates of angle reference point 4 are (X4, Y4, Z4), and Y3 = Y4 is satisfied to ensure that the reference line is horizontal. The target posture requires that the line connecting angle reference point 3 and angle reference point 4 is perpendicular to the XY plane, i.e., the line is in a vertical state in space. According to this target, the spatial position to which node 3 should reach is determined, and the fixed end node (node 4) of the beam element is set at this position, with coordinates (a4, b4, c4). The initial direction of the beam element is also set to be parallel to the XZ plane to ensure that the driving direction has no deviation in the Y-axis direction. After starting the beam element contraction function, node 3 moves towards node 4 under the action of the element and eventually coincides with it, driving the lower leg to rotate around the knee joint and ankle joint, and making the tibia reach the target vertical posture. This movement process synchronously adjusts the position of the lower leg muscles and foot soft tissues, completing the precise matching of the lower limb posture.

[0065] The coordinate mark of node 4 can be calculated by angle reference node 3, angle reference node 4 and node 3, and the calculation formula is:

[0066] .

[0067] The application realizes accurate control of joint angles of the digital human model by introducing the posture adjustment technology based on the beam unit contraction mechanism, can realize high-precision angle control of key parts such as the femur and the lower leg, and makes the model posture highly consistent with the PMHS test conditions. In the process of bone movement, the bone drives the synchronous displacement of the connected soft tissues such as muscles and fats, thereby generating initial strain and prestress distribution conforming to physiological characteristics in the model, avoiding the problems of soft tissue distortion or stress loss caused by the traditional adjustment mode, and making the model in a real biomechanical preloading state before impact.

[0068] S6, the working conditions of fusion reaction force loading, fixed constraint of key skeletal parts, target posture adjustment, impact hammer impact and digital human model gravity loading, activate and fail through time sequence control each working condition, complete the digital human model lower limb impact verification method.

[0069] In some embodiments, specifically including:

[0070] According to the biomechanical simulation requirements, the total time of the whole working condition is divided into: an initial time period and a subsequent time period;

[0071] The initial time period: maintain the reaction force loading, fixed constraint of key skeletal parts and target posture adjustment working conditions, wherein: the reaction force loading working condition is activated to simulate the extrusion effect of the seat on the digital human model; the fixed constraint of key skeletal parts working condition is activated to inhibit the displacement of the digital human model; and the target posture adjustment working condition is activated to adjust the joint angle through beam unit contraction driving;

[0072] The subsequent time period: remove the fixed constraint of key skeletal parts, and simultaneously start the impact hammer impact and the digital human model gravity loading working conditions, wherein: the impact hammer impact working condition is activated to apply an acceleration load to the target part of the lower limb; and the digital human model gravity loading working condition is activated to restore the gravity action of the human body.

[0073] Specifically, in order to complete the accurate simulation verification of the lower limb impact response of the digital human model, multiple physical working conditions such as reaction force loading, fixed constraint of key skeletal parts, target posture adjustment, impact hammer impact and human body gravity loading are fused, and the activation and failure of each working condition are controlled through accurate time sequence, to realize dynamic simulation of the whole process.

[0074] In this embodiment, the total time of the entire working condition is set to 450 ms, which is divided into an initial time period (0-300 ms) and a subsequent time period (300-450 ms) according to the time stage, and each working condition cooperates in sequence.

[0075] The initial state is shown in Figure 7 a, and then, in the initial time period (0-300 ms), as shown in Figure 7 b, the counterforce loading working condition is first activated: a concentrated force is applied at the geometric center of the seat contact surface, with a size equal to the product of the mass of the thigh and upper torso of the digital human model and the acceleration of gravity (g = 9.8 m / s²), and a direction perpendicular to the seat surface upward, simulating the extrusion of the seat on the human body during static support. At the same time, the fixed constraint working condition of key skeletal sites is activated, which applies displacement constraints of full or partial degrees of freedom to the key nodes of the pelvis, ribs and spine to prevent the model from undergoing non-physiological overall translation or shaking under the action of the counterforce, ensuring posture stability. In the 0-200 ms of this stage, the target posture adjustment working condition is activated: by defining a contraction type beam element, one end node (node 1, node 3) is co-nodal with the target bone (such as the distal femur or ankle midpoint), and the other end node (node 2, node 4) is placed at the target position, the complete contraction function of the beam element is started, and its length gradually shortens from the initial value to zero, driving the bone node to move to the target position, thus achieving precise adjustment of the femur and lower leg joint angle. During 200-300 ms, the beam element has completed contraction, and the two nodes coincide, maintaining this state to stabilize the final posture. At the same time, during 0-300 ms, the impact hammer remains in a static state and does not apply any dynamic load; the self-gravity of the digital human model is temporarily canceled to avoid initial stress imbalance caused by superimposing the counterforce.

[0076] After entering the subsequent time period (300-450 ms), as shown in Figure 7As shown in FIG. 6, the working condition switching and dynamic loading are performed. At the time of 300 ms, the key bone fixation constraints of the pelvis, ribs and spine are released, and all the restricted degrees of freedom are released, so that the digital human body model enters a free dynamic response state. The impact hammer impact working condition is started synchronously: the impact hammer moves at a preset impact speed (such as 6.7 m / s) in a specified direction, starts to contact the knee joint area at the time of 300 ms, and continuously applies impact load in the subsequent time, simulating the dynamic response in the real lower limb impact process. At the same time, the gravity loading working condition of the digital human body model is activated, and the overall gravity of the human body is restored at the time of 300 ms, that is, the vertical downward gravity acceleration (9.8 m / s²) is applied to all mass units of the model, so that it is in the real gravity environment in the impact process. In addition, the seat plate is set to a fixed constraint state at the time of 300 ms, and the movement is stopped and rigid support is provided to simulate the constraint effect of the vehicle structure on the seat in the impact. The beam unit used for posture adjustment before 300 ms is set to be completely disabled after 300 ms, and no longer participates in the mechanical calculation.

[0077] Through the above time sequence control strategy, the orderly fusion of multiple physical working conditions is realized: the model posture adjustment, stable support and preloading are completed within 0-300 ms, and a reasonable initial contact state is established; the constraints are released, the gravity is restored and the impact load is applied within 300-450 ms, and the real impact dynamics analysis stage is entered.

[0078] The present application realizes the smooth transition from static preloading to dynamic impact through multi-working condition fusion and time sequence cooperative control. In the early stage, the posture adjustment, counterforce loading and bone fixation are completed, and a high-fidelity initial contact state is established; in the impact stage, the constraints are released, the body's own gravity is restored and the impact load is applied, ensuring the logical coherence of each physical process, the smooth switching of boundary conditions, and avoiding numerical oscillation or simulation instability. The overall scheme simultaneously approaches the real human body state in two aspects of geometry matching and mechanical response, significantly improves the biomechanical authenticity and test comparability of the digital human body model in lower limb impact simulation, and provides a higher confidence simulation basis for damage mechanism analysis and safety system optimization.

[0079] It should be noted that the terms used in the present application are only intended to describe specific embodiments and are not intended to limit the scope of the present application. As shown in the specification of the present application, unless the context clearly indicates otherwise, "one", "a", "an", and / or "the" do not specifically refer to the singular, but can also include the plural. The terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of additional identical elements in the process, method or device including the element.

[0080] It should also be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only intended to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. Unless otherwise specified and limited, the terms "mount", "connect", "connect" and the like should be broadly understood, for example, it can be a fixed connection, or it can be a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application.

Claims

1. A high-biomimetic digital human body model lower limb impact verification method, characterized in that, The method comprises the following steps: Based on the biomechanical response data, a collision simulation environment is built, including: impact hammer model and rigid seat model; Position the digital human model to the target impact position; Simulate the interaction between the gravity of the digital human model and the rigid seat model, and establish a reaction force loading mechanism based on seat contact surface force analysis; During the reaction force loading process, fixed constraints are applied to the key skeletal parts of the digital human model; Adjust the joint posture of the digital human model to the target posture through the driving unit; Fusion of reaction force loading, key skeletal part fixed constraint, target posture adjustment, impact hammer impact and digital human model gravity loading working condition, through time sequence control each working condition activation and invalidation, complete digital human model lower limb impact verification method, specifically including: According to the biomechanical simulation requirements, the total time of the whole working condition is divided into: initial time period and subsequent time period; Initial time period: maintain the reaction force loading, key skeletal part fixed constraint and target posture adjustment working condition, wherein: the reaction force loading working condition is activated, which simulates the extrusion effect of the seat on the digital human model; the key skeletal part fixed constraint working condition is activated, which inhibits the displacement of the digital human model; the target posture adjustment working condition is activated, which adjusts the joint angle through the beam unit contraction driving; Subsequent time period: remove the key skeletal part fixed constraint, and simultaneously start the impact hammer impact and digital human model gravity loading working condition, wherein: the impact hammer impact working condition is activated, which applies acceleration load to the target part of the lower limb; the digital human model gravity loading working condition is activated, which restores the gravity effect of the human body itself.

2. The high-biomimetic digital human body model lower limb impact verification method according to claim 1, characterized in that, The positioning of the digital human model to the target impact position also includes: Set the distance between the hip contact surface of the digital human model and the seat contact surface to avoid physical penetration, and the distance is determined based on the sum of the outermost shell thickness of the digital human model and the seat thickness.

3. The high-biomimetic digital human body model lower limb impact verification method according to claim 1, characterized in that, The force analysis includes: Measure the thigh and seat contact surface and above torso mass of the digital human model, and measure the mass point of the geometric center of the seat contact surface based on the seat mass and the thigh and seat contact surface and above torso mass of the digital human model.

4. The high-biomimetic digital human body model lower limb impact verification method according to claim 1, characterized in that, The reaction force loading mechanism includes: Apply a vertical upward force to the seat that is equivalent to gravity.

5. The high-biomimetic digital human body model lower limb impact verification method according to claim 1, characterized in that, The key skeletal parts include: pelvis, ribs and spine.

6. The high-biomimetic digital human body model lower limb impact verification method according to claim 1, characterized in that, The driving unit is a fully contracted beam unit, which is bound to the skeleton through a first node and fixed to the target position through a second node. The beam unit drives the displacement of the skeleton and soft tissue through contraction movement, and adjusts the joint posture of the digital human model to the target posture.

7. The high-biomimetic digital human body model lower limb impact verification method according to claim 6, characterized in that, The adjustment of the joint posture is for the lower limbs, including: Femur angle adjustment: define the first node at the distal end of the femur, and determine the target position based on the parallel relationship between the femur reference point connection line and the plane; Calf angle adjustment: define the first node at the midpoint of the ankle, and determine the target position based on the vertical relationship between the calf reference point connection line and the plane.

Images