Human body balance function multi-posture evaluation method and device based on six-dimensional force measurement plate

Abstract

The invention discloses a human body balance function multi-posture evaluation method and device based on six-dimensional force plates, and the method comprises the steps: S1, placing and leveling two six-dimensional force plates side by side, and then connecting a data collection and processing terminal; s2, guiding the subject and checking the posture, and starting the test; s3, six-dimensional force / torque data are collected, data preprocessing is carried out, and each core index is calculated; and S4, based on each core index and the personal data of the subject, automatically generating a human body balance function evaluation report. The device is operated by adopting the method. According to the invention, the two six-dimensional force measuring plates arranged side by side are combined with the data acquisition and processing terminal, so that multi-posture standardized evaluation of the balance function of the human body is realized; various standing postures can be verified, various parameters are calculated based on fusion processing of biped mechanical data, a comprehensive report containing charts, interpretation, risk assessment and the like is finally and automatically generated, and objective and comprehensive quantitative data support is provided for the fields of clinical diagnosis, rehabilitation evaluation and the like.

Description

Technical Field

[0001] This invention relates to the fields of biomechanics, rehabilitation medicine and human factors engineering, specifically to a method and device for multi-posture assessment of human balance function based on a six-dimensional force plate. Background Technology

[0002] A Multi-Posture Assessment Method and Device for Human Balance Function Based on a Six-Dimensional Force Plate: Human balance ability is a key indicator for assessing nervous system function, musculoskeletal system status, and fall risk. Currently, commonly used balance assessment tools in clinical practice and research include clinical scales such as the Berg Balance Scale and the Tinetti Balance Scale. These scales rely on the therapist's subjective observation and scoring, and while convenient, they lack objective quantitative data and have low sensitivity.

[0003] While a single force plate can objectively measure the trajectory of the center of pressure (CoP), it typically treats both feet as a single unit, making it difficult to accurately analyze the pressure distribution and interaction forces between the feet, and thus challenging to assess asymmetry and detailed biomechanics in specific postures. Dynamic posture charts are expensive, complex to operate, and primarily used for testing dynamic balance or sensory integration; they are not well-suited for the detailed assessment of basic static postures.

[0004] Existing dual-force plate testing methods mostly use two independent four-dimensional (measuring only three-dimensional force + vertical torque) platforms, which cannot fully obtain the mechanical information of the six degrees of freedom of each foot. Furthermore, they lack standardized testing posture procedures and automated data analysis and interpretation systems, resulting in low testing efficiency and results that are highly dependent on the operator's experience. Summary of the Invention

[0005] To address the aforementioned issues, the present invention aims to propose a multi-posture assessment method and device for human balance function based on a six-dimensional force plate. This method involves simultaneously collecting six-dimensional force / torque data from the subject's feet using two side-by-side six-dimensional force plates. Combined with an optical motion capture system, the method provides standardized assessment and guidance for the subject's static standing posture. Three standard test postures are set: "feet level," "feet staggered," and "feet in line." After the subject's posture is confirmed by the motion capture system to meet the standards, the balance test is initiated. The data processing module performs spatiotemporal synchronization, coordinate unification, and mechanical fusion of the dual-plate data, calculating the overall pressure center trajectory and a series of quantitative balance parameters. Finally, based on a built-in algorithm and a norm database, a report containing data charts and risk assessments is automatically generated, achieving highly efficient, automated, and standardized assessment throughout the entire process from posture guidance, data acquisition, analysis to report output.

[0006] This was achieved through the following technical solutions: First, a multi-posture assessment method for human balance function based on a six-dimensional force plate is proposed, including the following steps: S1. Test preparation: Place the two six-dimensional force plates side by side and level them before connecting them to the data acquisition and processing terminal; the data acquisition and processing terminal includes an optical motion capture system, an acquisition software system, and a report generation system. S2. Guide the subject and calibrate the posture: Guide the subject to stand still on two six-dimensional force plates; first, use the optical motion capture system to acquire the subject's posture image, then synchronize it to the acquisition software system and calibrate it with the preset standard posture database. When the calibration standard is met, turn on the two six-dimensional force plates and let the subject perform various balance posture tests on the two six-dimensional force plates. S3. Data Acquisition and Processing: The acquisition software system is used to obtain six-dimensional force / torque data from two six-dimensional force plates, and then data preprocessing and calculation of each core index are performed sequentially. Among them, data preprocessing includes filtering and noise reduction, spatiotemporal synchronization and coordinate system unification, and fusion of mechanical parameters. Each core index includes basic mechanical charts, pressure center trajectory analysis index, and comprehensive evaluation parameters. S4. Automatic Report Generation: Based on each core indicator and the subject's personal data, the system automatically generates a corresponding human balance function assessment report.

[0007] Preferably, in step S1, each of the two six-dimensional force measuring plates is connected to a gateway, which is used to connect to the data acquisition software system wirelessly; or both six-dimensional force measuring plates are connected to the data acquisition software system via gigabit Ethernet cables or dedicated synchronization cables. The gateway enables flexible connection between the six-dimensional force measuring plates and the data acquisition system, supporting wired or wireless transmission modes, improving the convenience of system deployment and the stability of data transmission, and adapting to the needs of different testing environments.

[0008] Preferably, both six-dimensional force measuring plates are marked with footprint directions corresponding to various balance postures; these various balance postures include at least standing with both feet level, standing with both feet staggered, and standing with both feet in a straight line. Marking the footprint directions corresponding to various balance postures on the force measuring plates guides the subject to stand accurately, standardizes the testing movements, reduces errors caused by positioning deviations, and improves the consistency and repeatability of the test.

[0009] Preferably, during calibration in step S2, the acquired posture images are first processed sequentially in the acquisition software system using 2D point recognition, 3D reconstruction, marker point identification, and skeletal modeling. Data in C3D and CSV formats is exported and subjected to biomechanical analysis to create BVH or FBX animation images. These animation images are then compared with a standard posture database, and calibration is judged based on a set difference range. If the calibration criteria are met, two six-dimensional force plates are activated, and various balance posture tests are prepared. If the calibration is not met, the optical motion capture system provides a highlighting warning. By performing posture calibration through the optical motion capture system and comparing it with the standard posture database, automated posture calibration is achieved, ensuring that the initial test posture conforms to the standard and improving the accuracy and objectivity of the evaluation.

[0010] Preferably, in step S3, during the filtering and denoising process, a threshold filter is first used to remove high-frequency noise from the six-dimensional force / torque data, followed by moving average filtering using a Butterworth low-pass filter. Then, a baseline correction algorithm based on the no-load period is used to eliminate bias. Simultaneously, a six-dimensional force threshold is set based on the subject's weight, and truncation is performed according to this threshold. Filtering and denoising effectively eliminates high-frequency noise and system bias, improves data quality, and provides reliable signals for subsequent analysis.

[0011] Preferably, in step S3, when performing spatiotemporal synchronization and coordinate system integration, the six-dimensional force / torque data of the two six-dimensional force measuring plates are first timestamped, and then the center between the two six-dimensional force measuring plates is selected as the origin for coordinate system integration. This spatiotemporal synchronization and coordinate fusion of the dual-plate data provides a consistent spatial reference for the overall mechanical analysis.

[0012] Preferably, during the fusion of mechanical parameters in step S3, the six-dimensional force / torque data of the completed spatiotemporal synchronization and coordinate system one are fused and calculated into the corresponding resultant force and resultant torque; wherein, the global pressure center of the resultant torque is solved accordingly through the torque balance equation. Mechanical parameter fusion can integrate the mechanical information of the two plates, comprehensively reflect the overall force state of the subject, and provide core analytical data for balance function assessment.

[0013] Preferably, in step S3, the basic mechanical diagrams include at least the six-dimensional force diagrams of the left and right feet, the vertical resultant force diagrams of the left and right feet, the trajectory diagrams of the pressure centers of both feet, the change diagram of the angle between the line connecting the pressure centers of the left and right feet and the selected direction, the center of gravity frequency analysis diagram, the projection diagrams of both feet, and the three-dimensional surface force diagrams. The pressure center trajectory analysis indicators include displacement amplitude, total trajectory length of the pressure center, average velocity of the pressure center, area of ​​the 95% confidence ellipse, fractal dimension of the biaxial direction in the unified coordinate system, total oscillation distance of the pressure center along the biaxial direction, and bending moment impulse and deflection angle of the pressure center along the biaxial direction. The comprehensive evaluation parameters include pressure center symmetry, Romberg quotient, and balance bundle. Multiple core indicators are defined to quantify the balance function characteristics from multiple dimensions, achieving a comprehensive and detailed analysis of human balance ability.

[0014] Preferably, in step S4, the human balance function assessment report includes at least: subject information, a stress center trajectory diagram, a core indicator data table, a results summary, and a fall risk warning. This allows for the rapid generation of a structured assessment report, providing a clear and intuitive presentation of test results for easy interpretation and analysis.

[0015] Secondly, a device is proposed that operates using any of the above-mentioned methods for multi-posture assessment of human balance function based on a six-dimensional force plate. This device includes a data acquisition and processing terminal and two six-dimensional force plates placed side-by-side. The data acquisition and processing terminal includes an optical motion capture system, an acquisition software system, and a report generation system. The two six-dimensional force plates are used to simultaneously acquire six-dimensional force / torque data from both feet. The optical motion capture system is used to capture the standing posture image of the subject, and the acquisition software system is used to calibrate the posture image, preprocess the data, and calculate each core indicator. The report generation system generates a corresponding human balance function assessment report based on the calculation results from the acquisition software system.

[0016] The beneficial effects of this invention compared to the prior art are: The technical solution of this invention synchronously collects six-dimensional force / torque data of the subject's feet using two six-dimensional force plates placed side by side. Combined with an optical motion capture system, it standardizes and guides the subject's static standing posture, setting three standard test postures: "feet level," "feet staggered," and "feet in a straight line." After the subject's posture is confirmed by the motion capture system to meet the standards, a balance test is initiated. The data processing module performs spatiotemporal synchronization, coordinate unification, and mechanical fusion of the dual-plate data, calculating the overall pressure center trajectory and a series of quantitative balance parameters. Finally, based on the built-in algorithm and norm database, it automatically generates a report containing data charts and risk assessments, achieving highly efficient, automated, and standardized evaluation throughout the entire process from posture guidance, data collection, analysis to report output. Attached Figure Description

[0017] Figure 1This is a flowchart of a multi-posture assessment method for human balance function based on a six-dimensional force plate. Detailed Implementation

[0018] The following will be based on embodiments of the present invention. Figure 1 The technical solutions in the embodiments of the present invention will be described in detail below.

[0019] like Figure 1 The diagram shows a flowchart of a multi-posture assessment method for human balance function based on a six-dimensional force plate. By combining two six-dimensional force plates placed side-by-side with an optical motion capture system, a standardized multi-posture assessment of human balance function is achieved. The system automatically guides and verifies three standard standing postures: "side-by-side," "off-side," and "cross-legged." It simultaneously collects biomechanical data from both feet, processes the data, calculates the pressure center trajectory and multiple quantitative balance parameters, and finally automatically generates a comprehensive report including charts, interpretations, and risk assessments. The entire process automates and standardizes the assessment workflow, providing objective and comprehensive quantitative data support for clinical diagnosis and rehabilitation assessment, significantly improving assessment efficiency and accuracy.

[0020] The multi-posture assessment method for human balance function in this embodiment specifically includes the following steps: S1. Test preparation: Place two six-dimensional force plates side by side on a flat, level surface and perform leveling operations until the surfaces of the two force plates are on the same horizontal plane. Then connect the two six-dimensional force plates to the data acquisition and processing terminal. The data acquisition and processing terminal includes an optical motion capture system, an acquisition software system, and a report generation system.

[0021] The two six-dimensional force measuring boards can support wired or wireless connections. In wired connection mode, both boards connect to the data acquisition software system via a gigabit Ethernet cable or a dedicated synchronization cable. In wireless connection mode, each board connects to a gateway, which then connects to the data acquisition software system wirelessly. The data acquisition software system is the dedicated analysis software within the industrial control computer (acting as the host computer). The gateway can be a multimodal wireless aggregation gateway, with the two six-dimensional force measuring boards acting as terminal nodes. This dedicated network ensures high bandwidth and low latency. Taking Wi-Fi wireless mode as an example, the matrix setup for wireless communication within the six-dimensional force measuring board requires configuring two six-dimensional force measuring boards as Wi-Fi client mode. Both boards are connected to the same Wi-Fi network. The router automatically assigns IP addresses to the two force measuring boards. The host computer connects to the same Wi-Fi network created by the router, placing it on the same local area network as the two force measuring boards. Then, via Socket communication, the host computer's data acquisition software sends control commands (such as start acquisition, stop acquisition) to the IP addresses and preset ports of the two force measuring boards, and synchronously receives and stores data. A gateway enables flexible connection between the six-dimensional force measuring board and the acquisition system, supporting wired or wireless transmission modes, improving the convenience of system deployment and the stability of data transmission, and adapting to the needs of different testing environments.

[0022] Both six-dimensional force measuring plates are marked with footprint direction labels corresponding to various balance postures, including standing with both feet level (solid black line), standing with both feet staggered (dashed black line), and standing with both feet in a straight line (gray fill). The labels are used to distinguish and guide the subject's standing posture and position, standardize the test movements, reduce errors caused by position deviations, and improve the consistency and repeatability of the test.

[0023] It should be noted that the selected subjects must exclude those with obvious postural problems, such as tilting, limping, or hunchback. Before the test, approximately 50 patches are applied to the subjects for identification and judgment by the optical motion capture system.

[0024] S2. Guiding and Calibrating the Subject's Posture: Guide the subject to stand still on two six-dimensional force plates. First, use an optical motion capture system to acquire the subject's posture image, then synchronize it to the acquisition software system and calibrate it against a preset standard posture database. Once the calibration criteria are met, turn on the two six-dimensional force plates and have the subject perform various balance posture tests on them. These balance postures should include at least two feet level, two feet staggered, and two feet in a straight line.

[0025] Before the test began, the subjects removed their shoes and stood on a soft mat in front of the force measurement matrix. The operator controlled the industrial control computer to zero the data on the two six-dimensional force measurement plates. Then, the operator gave the instruction that the subjects step onto the left and right force measurement plates respectively, and stand naturally and still according to the corresponding footprint markings on the six-dimensional force measurement plates, ensuring their feet did not extend beyond the marked area. Furthermore, the subjects were required to maintain a natural and relaxed standing posture: upright body, eyes looking straight ahead, feet shoulder-width apart or slightly narrower, toes slightly turned outward (approximately 5-15°), and arms hanging naturally. To avoid environmental influences, a solid red circle was placed in front of the subjects as a guide; while standing, the subjects were instructed to look straight ahead and focus on the solid red circle.

[0026] After the subject has stabilized on the force plate matrix, the optical motion capture system assesses their posture. This system uses a high-speed infrared camera to capture light reflected from marked points. Combined with a high frame rate (e.g., 100-1000Hz or higher) hardware interface, the camera captures an image of the subject standing still and synchronizes it to the acquisition software system. The software system completes the steps of "2D point recognition → 3D reconstruction → marker point identification → skeletal modeling," exporting data in C3D and CSV formats for biomechanical analysis to create BVH or FBX animation images. These animation images are then compared to a standard posture database, and a calibration judgment is made based on a set difference range. For example, "a deviation of joint angles from the standard deviation within ±3~5° is considered normal," "a pelvic height difference <5mm is considered symmetrical," and "a head tilt distance <5cm is normal" are used to determine if the subject's natural standing posture is standard. Once the calibration criteria are met, two six-dimensional force plates are activated, and various balance posture tests are prepared. If the calibration fails to meet the specified standards, the optical motion capture system highlights the subject's posture, requiring the subject to adjust their posture to avoid significant postural differences caused by individual habits. The balance test begins once the subject's posture is deemed acceptable (i.e., no further highlighting occurs). Posture calibration is performed via the optical motion capture system and compared with a standard posture database, achieving automated posture calibration and ensuring that the initial test posture conforms to the standard, thus improving the accuracy and objectivity of the assessment.

[0027] S3. Data Acquisition and Processing: The acquisition software system is used to obtain six-dimensional force / torque data from two six-dimensional force plates, and then data preprocessing and calculation of each core index are performed sequentially. Among them, data preprocessing includes filtering and noise reduction, spatiotemporal synchronization and coordinate system unification, and fusion of mechanical parameters. Each core index includes basic mechanical charts, pressure center trajectory analysis index, and comprehensive evaluation parameters.

[0028] When the balance test is initiated, the operator clicks "Start Acquisition" to send control commands to the two six-dimensional force plates. After the subject has stably stood on the force plates for 10 seconds, they leave the force plates and click "End Acquisition." The processors built into the two plates package this six-dimensional force information (force / torque data), along with status information (such as error codes), into Ethernet data frames and transmit them to the acquisition software system. Simultaneously, the network cable transmits the digitized six-dimensional force information, obtaining an SQLite database file, which is then stored synchronously. Meanwhile, the UI thread is responsible for responding to user operations and updating the screen display, and the terminal software interface updates the graphical mechanical data in real time. This test procedure is used to complete balance force tests in three postures: standing with feet parallel (together), standing with feet staggered (offset), and standing with feet in a straight line (seamless). Both six-dimensional force plates have coordinate systems defined in the +x and +y directions on the horizontal plane. The direction the subject faces when standing in a "parallel" or "separated" posture is aligned with the +x direction of the force plate, and the direction they face after rotating 90° counterclockwise is aligned with the +y direction. This directional specification applies to the entire balance test. The specific test procedures for the three balance postures are as follows: Posture 1: The operator operates the host computer, selects the "two feet level" (parallel) mode, and clicks "start data collection". The subject stands on the left and right force plates with his / her left and right feet level, facing the same direction as the "+x" of the force plate, with his / her eyes looking straight ahead and his / her arms hanging naturally. After the subject's posture is stable, the data is collected for 10 seconds. Then, the operator clicks "end data collection", the subject leaves the force plate, and the data is stored synchronously.

[0029] Posture 2: After completing the test in Posture 1, the subject steps off the board, and the operator selects the "staggered feet" mode on the software and clicks "Start Data Collection". Following the on-screen instructions or operator guidance, the subject re-enters the board with one foot forward and one foot back in a staggered position. Once the subject's posture is stable, data collection is performed for 10 seconds, then "End Data Collection" is clicked, and the subject leaves the force plate while the data is simultaneously stored.

[0030] Posture 3: Finally, conduct the "two-footed straight line" (serial) test. The operator selects the "two-footed straight line" (serial) mode on the software and clicks "Start Data Acquisition". The subject faces the "+y" direction onto the board, with the toes of both feet pointing towards the "+y" direction, stepping onto the left and right force plates respectively, with both feet in a straight line. After the subject's posture stabilizes, data is collected for 10 seconds, then "End Data Acquisition" is clicked, the subject leaves the force plate, and the data is stored simultaneously.

[0031] In this embodiment, after obtaining the subject's six-dimensional force information, preprocessing of the six-dimensional force information is required. First, filtering and noise reduction are performed, using a threshold filter to filter any original force (F) in the six-dimensional force information. x , F y, F z ) and torque (M) x M y M z All signals are smoothed to remove high-frequency noise. Next, a Butterworth low-pass filter is used for signal conditioning, with a cutoff frequency of 20Hz set to retain biomechanically effective components while suppressing high-frequency noise. A moving average filter is applied using the formula y[n] = (x[n] + x[n-1] + ... + x[n-k+1]) / k, where n is a positive integer and k is no greater than n-2. Furthermore, to address potential data drift during processing, a baseline correction algorithm based on no-load periods (i.e., when no one is standing) can automatically detect and eliminate system biases. Simultaneously, a verification module is included to determine if data exceeds a threshold range. G =3 G r ( G r Abnormal force values ​​(based on the subject's weight) were identified as noise and truncated to ensure the filtered data met biomechanical constraints. Filtering and denoising effectively eliminated high-frequency noise and system bias, improved data quality, and provided reliable signals for subsequent analysis.

[0032] It should be noted that the core purpose of the baseline correction algorithm is to eliminate the small, non-zero force / torque readings that may occur when the six-dimensional force plate is unloaded (without a person standing on it), due to sensor characteristics (such as temperature drift and zero drift), circuit noise, or residual installation stress. These readings do not represent the actual force applied by the subject and can be called systematic bias or zero-point offset. Without correction, these non-realistic offsets will be superimposed on the subsequently collected real human biomechanical data, causing systematic errors in the calculated mechanical parameters (such as total pressure and pressure center position), affecting the accuracy of the assessment and the comparability between different tests and different devices.

[0033] When using the baseline correction algorithm, a no-load period is first defined when the two force plates are unloaded. Force and torque data are collected multiple times during this no-load period as multiple baselines. Then, the average value of the force or torque in each direction is calculated to obtain the corresponding offset (or drift). Thus, by subtracting the corresponding offset from the force or torque data in each direction in the test data of the subject, the actual force and torque data of the subject can be obtained.

[0034] When performing spatiotemporal synchronization and coordinate system unification, the six-dimensional force / torque data of the two six-dimensional force measuring plates are first time-stamped and then the center between the two six-dimensional force measuring plates is selected as the origin for coordinate system unification. The key to force measurement of the two plates is to achieve unified acquisition of the left and right foot forces, that is, to time-stamp align the six-dimensional force / torque data streams acquired by the left and right force measuring plates to ensure data synchronization; at the same time, the local coordinate systems of the left and right six-dimensional force measuring plates need to be uniformly transformed to the global coordinate system with the center of the two plates as the origin, which facilitates subsequent data fusion. Time synchronization can adopt a dual strategy, namely, using TTL pulse signals to achieve sampling clock synchronization at the hardware level; and calculating the time shift R{xy}[m] = Σ x[n]y[n+m] based on the cross-correlation function at the software level, where n and n+m represent the time points corresponding to the acquisition of data by the two plates, m is the time shift, x and y represent the signals / data acquired by the two plates, R represents the cross-correlation function, time alignment is performed based on the time shift, and R is the rotation matrix, which can be obtained by finding the vertical force signal. F z The cross-correlation peak value is used to determine the optimal time shift parameters. The rotation matrix R is determined by installing Euler angles on a six-dimensional force plate, and the translation vector... t Derived from the precise spatial location measured by a total station, the transformation from a local coordinate system to a globally unified coordinate system is achieved by establishing a homogeneous transformation matrix.

[0035] When performing mechanical parameter fusion, the six-dimensional force / torque data that have achieved spatiotemporal synchronization and coordinate system one are fused and calculated into the corresponding resultant force and resultant moment; among them, the global pressure center of the resultant moment is solved for by the torque balance equation. Under a unified spatiotemporal framework, based on the principles of Newtonian mechanics, vector-level mechanical parameter fusion can be achieved, i.e., the resultant force F. res =F plate1 + F plate2 The resultant moment calculation takes into account the lever arm effect M. res = M plate1 + M plate2 + r1 × F plate1 + r2 ×F plate2 The global center of pressure is determined by the moment balance equation: COP x = (-M y - F x·z0 ) / F z COP y = (M x -F y·z0 ) / F z Where z0 is the vertical distance from the surface of the force plate to the origin of the sensor, and COP represents the center of pressure; this fusion of mechanical parameters can obtain the true overall load distribution information, comprehensively reflect the overall force state of the subject, and provide core analytical data for balance function assessment.

[0036] In this embodiment, the basic mechanics diagrams include a six-dimensional force diagram of the left and right feet, a vertical resultant force diagram of the left and right feet, a trajectory diagram of the pressure center of both feet, and a diagram showing the change in the angle between the line connecting the pressure centers of the left and right feet and the selected direction (denoted as...). β Angle change diagram), center of gravity frequency analysis diagram, bipedal projection diagram, and three-dimensional surface force diagram. Six-dimensional force diagrams for left and right feet: plotting the forces (F) acting on each foot in three directions throughout the entire test time. x , F y , F z ) and three-directional torque (M) x M y M z The curve showing how the left and right feet change over time. z Resultant force diagram: Plot the curves of the vertical support reaction force of the left and right feet as a function of time, respectively, to assess the symmetry of weight distribution. Bipedal center of pressure trajectory diagram: Plot the overall center of pressure (COP) movement trajectory throughout the entire test on the global XY plane, using different colors to distinguish different test phases. β Angle change diagram: β The angle is the angle between the line connecting the pressure centers of the left and right feet and the X-axis of the global coordinate system. A curve showing the change of this angle over time is plotted to assess stability in the standing direction. Center of gravity frequency analysis image: Fourier transforms are performed on the X and Y direction signals of the COP to obtain the frequency spectrum, and the dominant frequencies of body sway are analyzed. Bipedal projection diagrams and 3D surface force maps: Both display the pressure distribution on the soles of the feet in heatmap form.

[0037] The metrics for COP trajectory analysis include displacement amplitude, total trajectory length of the COP, average velocity of the COP, 95% confidence ellipse area, directional fractal dimension of the biaxial axes in a unified coordinate system, total oscillation distance of the COP along the biaxial axes, and bending moment impulse and deflection angle of the COP in the biaxial directions (X / Y). Displacement amplitude: The maximum range of COP offset in the X and Y directions. Total COP trajectory length: The cumulative total length of COP movement over the entire test time; a longer total length indicates more frequent balance adjustments and poorer stability. Average COP velocity: Total trajectory length / test time; a faster velocity indicates that the nervous system needs to exert more effort to maintain balance, resulting in lower control efficiency. 95% confidence ellipse area: The area of ​​the ellipse containing 95% of the COP data points; a larger area represents a larger spatial range of body sway and weaker balance ability; this is the gold standard for assessing stability. X / Y direction fractal dimension: Used to quantify the complexity and irregularity of the COP trajectory; a higher fractal dimension indicates a more complex trajectory, potentially suggesting a more refined and aggressive balance control strategy. Total distance on both sides of the primary / secondary directions: The total sway distance of the COP trajectory in the primary and secondary axis directions. X / Y direction bending moment impulse: The integral of the COP offset distance over time, reflecting the "total work" required to maintain balance; the larger the impulse, the higher the energy consumption and neuromuscular control cost required to maintain balance. Deflection angle: The angle between the primary axis of the COP trajectory and the X-axis of the global coordinate system, reflecting the dominant direction of body sway.

[0038] The comprehensive assessment parameters include pressure center symmetry, Romberg quotient, and balance bundle. Multiple core indicators are defined to quantify balance function characteristics from multiple dimensions, enabling a comprehensive and detailed analysis of human balance ability. Pressure center symmetry: assessed by calculating the average Fz force of the left and right feet or the distribution of COP along the X-axis. Asymmetry >10% suggests potential muscle imbalance, pain, or nerve damage (such as hemiplegia). Romberg quotient: (parameter value under closed-eye conditions) / (parameter value under open-eye conditions), commonly calculated using 95% of the ellipse area or total trajectory length. A quotient significantly greater than 1 (e.g., >2) indicates that the patient over-relies on visual compensation, and proprioception or vestibular function may be impaired. Balance score: a single comprehensive score (e.g., 0-100) synthesized based on multiple core indicators (such as ellipse area, average velocity, fractal dimension) using a specific weighted algorithm. A higher score indicates better overall balance function and is used for rapid assessment and rehabilitation progress tracking.

[0039] S4. Automatic Report Generation: Based on each core indicator and the subject's personal data, the system automatically generates a corresponding human balance function assessment report.

[0040] After all test postures are completed, the operator can click the "Generate Report" button on the host computer, select the generation format such as "Word", "PDF", "TIFF", "JPG", etc., and then start the report generation process by following the steps of "input requirements → generate framework → content filling → table output → format adjustment". Input Requirements: Based on the user's input regarding the topic, objectives, content requirements, and formatting, natural language understanding technology is used to convert this information into a computer programming language, issuing and executing commands to the program. Framework Generation: Based on user requirements, the system rationally divides the report into chapters and content, checks the logic of the chapter divisions, and selects an optimal framework based on a large model. Simultaneously, the system calls a pre-set report template conforming to medical report standards to generate the content framework. Content Filling: Detailed test results are sequentially filled in according to chapters. A contextual memory mechanism is introduced to avoid repetitive content filling. All calculated indicator results and charts are automatically inserted into their corresponding positions in the template. Knowledge bases from professional fields such as biokinetics and dynamics are incorporated to ensure the accuracy of the generated content. Finally, a multi-round iterative mechanism is used to gradually improve the results report and provide a concise textual description of the results. Table Output: Based on the generated content, the target parameters are summarized in a table, and data differences are visually expressed through charts. The system automatically retrieves reference ranges from the built-in norm database based on the subject's age, gender, height, and weight, and displays the subject's results in percentile or Z-score format for comparison. Formatting: Polish the output content, use grammar checking tools to check for grammatical, logical and spelling errors, and combine with a professional terminology database to enhance the professionalism of the generated report.

[0041] A human balance function assessment report should include at least: subject information, stress center trajectory diagram, core indicator data table, results summary, and fall risk warning. This information presents the subject's assessment status in a visual way, facilitating quick interpretation and analysis.

[0042] The generated report will include the following sections (cover page, test summary, data details page, interpretation and recommendations, format output, data comparison, and final report file) and will have clear clinical interpretation guidelines.

[0043] The cover page includes subject information, test date, operator, and test conditions (such as footwear condition).

[0044] Test Summary: A concluding statement, automatically generated by the software, such as "This subject exhibited a significant decrease in forward and backward directional control under closed-eye conditions, with obvious left-right asymmetry (the ratio of weight-bearing to left / right side), a large Romberg quotient, and a moderate risk of falling." Risk Level: Determined as "low risk," "medium risk," or "high risk" based on a pre-set algorithm.

[0045] The data details page includes: charts, which present each basic mechanical chart in turn; and data tables, which clearly list the measured values, norm reference values ​​(preset data in the standard attitude database), and deviations (Z value or percentage) of all COP trajectory analysis indicators and comprehensive evaluation parameters in tabular form.

[0046] Interpretation and Recommendations: Results interpretation explains key abnormal indicators, such as "95% confidence ellipse area significantly larger than the age-matched norm (Z-score = +2.5), indicating poor static postural stability." Clinical indications include poor anteroposterior control, potentially suggesting insufficient ankle plantarflexor / dorsiflexor muscle strength, calf muscle tension, or sagittal plane motor control dysfunction; poor lateral control may indicate hip adductor / abductor muscle weakness, proprioceptive abnormalities, or coronal plane control strategy dominance. A high Romberg quotient strongly suggests proprioceptive dysfunction, commonly seen in peripheral neuropathy and posterior column syndrome. High asymmetry points to unilateral dysfunction, such as after ankle sprains, knee osteoarthritis, or hemiplegia after stroke. Training recommendations are automatically provided based on weaknesses, such as: "Strengthening hip abductor muscle strength training and performing balance training while standing with eyes closed to enhance proprioceptive input." Output format: The final output is a PDF report with pictures and text, which can be printed or archived electronically.

[0047] Data comparison: Call the built-in norm database to calculate the Z-value or percentile.

[0048] The final report file automatically populates a pre-designed report template, generating a report in the target format. The report content includes subject information, CoP trajectory plot, parameter data table, bar chart / radar chart comparing with norms, results summary (e.g., "significantly decreased forward and backward directional control under eye-closed conditions"), and fall risk warning.

[0049] Furthermore, this application proposes a device that operates using the aforementioned multi-posture assessment method for human balance function based on a six-dimensional force plate. This device includes a data acquisition and processing terminal and two six-dimensional force plates placed side-by-side. The data acquisition and processing terminal includes an optical motion capture system, an acquisition software system, and a report generation system. The two six-dimensional force plates are used to simultaneously acquire six-dimensional force / torque data from both feet. The optical motion capture system is used to capture posture images of the subject standing, and the acquisition software system is used to calibrate the posture images, preprocess the data, and calculate each core indicator. The report generation system generates a corresponding human balance function assessment report based on the calculation results from the acquisition software system. The operation process and beneficial effects of this device are detailed in the aforementioned multi-posture assessment method for human balance function, and will not be repeated here.

[0050] In summary, this invention synchronously collects six-dimensional force / torque data of the subject's feet using two six-dimensional force plates placed side by side. Combined with an optical motion capture system, it standardizes and guides the subject's static standing posture, setting three standard test postures: "feet level," "feet staggered," and "feet in a straight line." After the motion capture system confirms that the subject's posture meets the standards, a balance test is initiated. The data processing module performs spatiotemporal synchronization, coordinate unification, and mechanical fusion of the dual-plate data, calculating the overall pressure center trajectory and a series of quantitative balance parameters. Finally, based on the built-in algorithm and norm database, it automatically generates a report containing data charts and risk assessments. This achieves highly efficient, automated, and standardized evaluation throughout the entire process from posture guidance, data collection, analysis to report output, demonstrating significant advancements.

[0051] The above embodiments are merely illustrative of the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solutions based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A multi-posture assessment method for human balance function based on a six-dimensional force plate, characterized in that, Includes the following steps: S1. Test preparation: Place the two six-dimensional force plates side by side and level them before connecting them to the data acquisition and processing terminal; the data acquisition and processing terminal includes an optical motion capture system, an acquisition software system, and a report generation system. S2. Guide the subject and calibrate the posture: Guide the subject to stand still on two six-dimensional force plates; first, use the optical motion capture system to acquire the subject's posture image, then synchronize it to the acquisition software system and calibrate it with the preset standard posture database. When the calibration standard is met, turn on the two six-dimensional force plates and let the subject perform various balance posture tests on the two six-dimensional force plates. S3. Data Acquisition and Processing: The acquisition software system is used to obtain six-dimensional force / torque data from two six-dimensional force plates, and then data preprocessing and calculation of each core index are performed sequentially. Among them, data preprocessing includes filtering and noise reduction, spatiotemporal synchronization and coordinate system unification, and fusion of mechanical parameters. Each core index includes basic mechanical charts, pressure center trajectory analysis index, and comprehensive evaluation parameters. S4. Automatic Report Generation: Based on each core indicator and the subject's personal data, the system automatically generates a corresponding human balance function assessment report.

2. The method for multi-posture assessment of human balance function based on a six-dimensional force plate according to claim 1, characterized in that, In step S1, each of the two six-dimensional force measuring plates is connected to a gateway, which is used to connect to the data acquisition software system in wireless transmission mode; or both six-dimensional force measuring plates are connected to the data acquisition software system via gigabit network cable or dedicated synchronization cable.

3. The method for multi-posture assessment of human balance function based on a six-dimensional force plate according to claim 1, characterized in that, Both six-dimensional force measuring plates are marked with the direction of the footprints corresponding to various balance postures; the various balance postures include at least standing with both feet level, standing with both feet staggered, and standing with both feet in a straight line.

4. The method for multi-posture assessment of human balance function based on a six-dimensional force plate according to claim 1, characterized in that, During the calibration process in step S2, the acquired posture images are first processed sequentially in the acquisition software system using 2D point recognition, 3D reconstruction, marker point identification, and skeletal modeling. Data in C3D and CSV formats is exported and biomechanical analysis is performed to create BVH or FBX animation images. The animation images are then compared with the standard posture database, and calibration is judged based on the set difference range. If the calibration criteria are met, two six-dimensional force plates are activated and various balance posture tests are prepared. If the calibration is not met, the optical motion capture system provides a highlighting reminder.

5. The method for multi-posture assessment of human balance function based on a six-dimensional force plate according to claim 1, characterized in that, In step S3, during the filtering and denoising process, a threshold filter is first used to remove high-frequency noise from the six-dimensional force / torque data, and a Butterworth low-pass filter is used for moving average filtering. Then, the baseline correction algorithm based on the no-load period is used to eliminate bias. At the same time, a six-dimensional force threshold is set based on the subject's weight, and truncation is performed based on the six-dimensional force threshold.

6. The method for multi-posture assessment of human balance function based on a six-dimensional force plate according to claim 1, characterized in that, In step S3, when performing spatiotemporal synchronization and coordinate system one, the six-dimensional force / torque data of the two six-dimensional force measuring plates are first timestamped, and then the center between the two six-dimensional force measuring plates is selected as the origin to perform coordinate system one.

7. The method for multi-posture assessment of human balance function based on a six-dimensional force plate according to claim 1, characterized in that, When performing mechanical parameter fusion in step S3, the six-dimensional force / torque data of the completed spatiotemporal synchronization and coordinate system one are fused and calculated into the corresponding resultant force and resultant torque; among them, the global pressure center of the resultant torque is solved by the torque balance equation.

8. The method for multi-posture assessment of human balance function based on a six-dimensional force plate according to claim 1, characterized in that, In step S3, the basic mechanics diagrams include at least the six-dimensional force diagrams of the left and right feet, the vertical resultant force diagrams of the left and right feet, the trajectory diagrams of the pressure centers of both feet, the change diagram of the angle between the line connecting the pressure centers of the left and right feet and the selected direction, the center of gravity frequency analysis diagram, the projection diagram of both feet, and the three-dimensional surface force diagram. The pressure center trajectory analysis indicators include displacement amplitude, total trajectory length of the pressure center, average velocity of the pressure center, area of ​​the 95% confidence ellipse, directional fractal dimension of the two axes in the unified coordinate system, total oscillation distance of the pressure center in the two axes, bending moment impulse and deflection angle of the pressure center in the two axis directions. The comprehensive evaluation parameters include pressure center symmetry, Romberg quotient, and equilibrium bundle splitting.

9. A multi-posture assessment method for human balance function based on a six-dimensional force plate according to claim 1, characterized in that, In step S4, the human balance function assessment report shall include at least: subject information, stress center trajectory diagram, core indicator data table, results summary, and fall risk warning.

10. A device, operating using a multi-posture assessment method for human balance function based on a six-dimensional force plate as described in any one of claims 1 to 9, characterized in that, It includes a data acquisition and processing terminal and two six-dimensional force plates placed side by side; the data acquisition and processing terminal includes an optical motion capture system, an acquisition software system, and a report generation system. Two six-dimensional force plates are used to simultaneously collect six-dimensional force / torque data of both feet; an optical motion capture system is used to capture the subject's standing posture image; the acquisition software system is used to calibrate the posture image, preprocess the data, and calculate each core indicator; the report generation system generates the corresponding human balance function assessment report based on the calculation results in the acquisition software system.

Images