A multi-sensor fusion human motion monitoring device

Abstract

This invention provides a multi-sensor fusion human motion monitoring device, relating to the field of human motion monitoring and intelligent rehabilitation assessment technology. The device synchronously collects human motion data through a trunk reference unit, a pelvic reference unit, a plantar load monitoring unit, and a reverse-parallel six-cable joint monitoring unit. It utilizes six flexible measuring cables to form relative joint posture constraints and combines inertial measurement, cable length encoding, cable tension sampling, and fixed-ring pressure balance data for fusion calculation to obtain joint angles, axial rotation, lateral displacement, and gait load changes. The central processing unit generates motion state assessment data based on the fusion results and drives the motion feedback unit to output prompts. This invention improves the continuity, stability, and joint micro-displacement recognition capability of human motion monitoring.

Description

Technical Field

[0001] This invention relates to the field of human motion monitoring and intelligent rehabilitation assessment technology, specifically to a multi-sensor fusion human motion monitoring device. Background Technology

[0002] Existing human motion monitoring devices mostly use inertial sensors, plantar pressure sensors, visual recognition devices, or single-string displacement sensors to collect motion data. Inertial sensors are prone to posture drift during prolonged use; visual recognition devices are limited by obstructions, lighting conditions, and site conditions; plantar pressure sensors can only reflect the support state; and single-string displacement sensors can only reflect local length changes and cannot directly reflect the spatial relative movement between adjacent bone segments. For rehabilitation monitoring of the knee, ankle, hip, shoulder, and elbow joints, relying solely on flexion and extension angles cannot accurately reflect joint center migration, axial rotation, lateral translation, and abnormal compensatory movements, resulting in a lack of continuous, accurate, and quantifiable motion data for rehabilitation training, exercise risk assessment, and home monitoring. Summary of the Invention

[0003] Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides a multi-sensor fusion human motion monitoring device, solving the following problems:

[0005] 1. It solves the problem that traditional human motion monitoring equipment mainly relies on a single inertial sensor for attitude estimation, which is prone to integral drift during long-term monitoring, resulting in cumulative errors in joint angles and motion trajectories, and failing to stably reflect the true relative motion of adjacent bone segments.

[0006] 2. It solves the problem that existing visual motion capture equipment is limited by site, lighting, occlusion and camera deployment conditions, making it difficult to use continuously in home rehabilitation, community elderly care, sports training and daily work scenarios.

[0007] 3. It solves the problem that existing plantar pressure monitoring devices can only reflect support and force changes, and cannot directly obtain the six degrees of freedom motion state of joints such as knee, ankle, and hip joints, making it difficult to identify joint center migration, axial rotation, and lateral displacement.

[0008] 4. This solves the problem that existing multi-sensor human motion monitoring solutions are mostly simple superpositions of inertial, pressure, rope, or communication modules, lacking unified motion geometry constraints among various data types, which makes the monitoring results easily affected by skin slippage, sensor loosening, soft tissue deformation, and single threshold judgment.

[0009] Technical solution

[0010] To achieve the above objectives, the present invention provides the following technical solution: a multi-sensor fusion human motion monitoring device, comprising a central processing unit, a trunk reference unit, a pelvic reference unit, a reverse parallel six-cable joint monitoring unit, a plantar load monitoring unit, a wireless communication unit, a motion feedback unit, and a power supply unit. The reverse parallel six-cable joint monitoring unit includes a proximal bone segment fixation ring, a distal bone segment fixation ring, a first flexible measuring cable, a second flexible measuring cable, a third flexible measuring cable, a fourth flexible measuring cable, a fifth flexible measuring cable, a sixth flexible measuring cable, a constant tension cable retraction assembly, an absolute length encoding assembly, a cable tension sampling assembly, a proximal inertial measurement assembly, a distal inertial measurement assembly, and a fixation ring pressure balancing assembly. The system includes components and an edge processor. The proximal and distal bone segment fixation rings are fixed along adjacent bone segments of the human body. Six flexible measuring cables form a spatial cross-connection structure between the proximal and distal bone segment fixation rings. The constant tension cable receiving component, absolute length encoding component, and cable tension sampling component are connected to their respective flexible measuring cables. The proximal inertial measurement component is mounted on the proximal bone segment fixation ring, and the distal inertial measurement component is mounted on the distal bone segment fixation ring. The edge processor is electrically connected to the absolute length encoding component, cable tension sampling component, proximal inertial measurement component, distal inertial measurement component, and fixation ring pressure balancing component. The edge processor is communicatively connected to the central processing unit.

[0011] Preferably, the proximal bone segment fixation ring is provided with six proximal cable connectors, and the distal bone segment fixation ring is provided with six distal cable connectors. The first flexible measuring cable and the second flexible measuring cable form a first cross cable pair, the third flexible measuring cable and the fourth flexible measuring cable form a second cross cable pair, and the fifth flexible measuring cable and the sixth flexible measuring cable form a third cross cable pair. The first cross cable pair, the second cross cable pair, and the third cross cable pair are arranged at intervals along the circumference of the fixation ring.

[0012] Preferably, both the proximal cable connector and the distal cable connector include a spherical hinge joint, a low-friction guide wheel, and a cable end limiting block. The flexible measuring cable passes through the low-friction guide wheel and the cable end limiting block in sequence, and the center line of the groove of the low-friction guide wheel coincides with the spatial orientation of the corresponding flexible measuring cable.

[0013] Preferably, the constant tension cable winding assembly includes a cable winding wheel, a constant force spring, a damping plate, and a one-way limiting toothed ring. The cable winding wheel is connected to a corresponding flexible measuring cable, the constant force spring is coaxially connected to the cable winding wheel, the damping plate is arranged to fit against the side of the cable winding wheel, and the one-way limiting toothed ring engages with the outer peripheral tooth surface of the cable winding wheel.

[0014] Preferably, the absolute length encoding component includes a multi-turn magnetic encoder disk, a magnetic reading chip, a zero-position marker, and an encoding bracket. The multi-turn magnetic encoder disk is coaxially fixed with the winding reel, the magnetic reading chip is mounted on the encoding bracket, and the zero-position marker is set at the initial winding position of the winding reel.

[0015] Preferably, the cable tension sampling assembly includes a micro cantilever beam, strain gauges, and a preloaded guide post. The flexible measuring cable bypasses the preloaded guide post and presses against the stressed end of the micro cantilever beam. The strain gauges are fixed in the root region of the micro cantilever beam.

[0016] Preferably, the fixing ring pressure balancing assembly includes three arc-shaped skin-fitting pressure pads, three sets of pressure sampling plates, a circumferential traction belt, and a differential tensioning wheel. The three arc-shaped skin-fitting pressure pads are arranged at intervals along the inner circumference of the proximal bone segment fixing ring or the distal bone segment fixing ring. The three sets of pressure sampling plates are respectively disposed between the three arc-shaped skin-fitting pressure pads and the corresponding fixing ring. The circumferential traction belt is wrapped around the outer circumference of the corresponding fixing ring, and the differential tensioning wheel is connected to the circumferential traction belt.

[0017] Preferably, the plantar load monitoring unit includes a heel pressure plate, a first metatarsal pressure plate, a fifth metatarsal pressure plate, an arch inertial measurement plate, and a plantar edge processing plate. The plantar edge processing plate is electrically connected to the heel pressure plate, the first metatarsal pressure plate, the fifth metatarsal pressure plate, and the arch inertial measurement plate, respectively. The plantar edge processing plate is communicatively connected to the central processing unit.

[0018] Preferably, the central processing unit includes a joint pose solving module, a cable credible constraint module, a fixed ring slip correction module, an instantaneous axis calculation module, and a motion corridor comparison module. The joint pose solving module is connected to the cable credible constraint module, the fixed ring slip correction module, and the instantaneous axis calculation module, respectively. The instantaneous axis calculation module is connected to the motion corridor comparison module.

[0019] A human motion monitoring method for a multi-sensor fusion human motion monitoring device according to any one of claims 1-9 includes the following steps:

[0020] Sp1, the proximal bone segment fixation ring and the distal bone segment fixation ring are fixed to the stable skin area of ​​the adjacent bone segment respectively, and the pressure sampling values ​​of the three arc-shaped skin-adhering pressure pads are obtained through the fixation ring pressure balancing component;

[0021] Sp2, record the initial absolute length, initial tension, initial attitude of the near-end inertial measurement unit, and initial attitude of the far-end inertial measurement unit of the six flexible measuring cables;

[0022] Sp3, during the motion, simultaneously sample the absolute length of the six flexible measuring cables, the tension of the six flexible measuring cables, the angular velocity and acceleration of the proximal inertial measurement unit, the angular velocity and acceleration of the distal inertial measurement unit, and the pressure data of the plantar load monitoring unit;

[0023] Sp4, the edge processor generates reliable weights for six flexible measurement cables based on the cable tension sampling values ​​and absolute length change values;

[0024] Sp5, the central processing unit solves the relative pose of adjacent bone segments based on the absolute length of the six flexible measuring cables, the reliable weights of the six flexible measuring cables, and the inertial predicted poses of the proximal inertial measurement unit and the distal inertial measurement unit.

[0025] Sp6, the central processing unit corrects the slippage of the fixing ring relative to the skin based on the migration of the pressure center of the three arc-shaped skin-fitting pads and the common length offset of the six flexible measuring cables;

[0026] Sp7, the central processing unit calculates the instantaneous motion axis of the joint, the displacement of the joint center, the lateral translation, and the axial rotation based on the corrected relative pose of adjacent bone segments;

[0027] The SP8 central processing unit generates motion monitoring results based on the instantaneous joint motion axis, joint center migration, lateral translation, axial rotation, and plantar load data, and transmits them to an external terminal via a wireless communication unit.

[0028] Beneficial effects

[0029] This invention provides a multi-sensor fusion human motion monitoring device. It has the following beneficial effects:

[0030] 1. This invention constructs a reverse parallel six-cable joint monitoring structure by using a proximal bone segment fixation ring, a distal bone segment fixation ring, and six spatially intersecting flexible measuring cables. This structure transforms the movement between adjacent bone segments into changes in the length of the six flexible measuring cables, enabling joint monitoring to move beyond a single angle output and form a comprehensive monitoring basis for joint flexion and extension, axial rotation, lateral translation, and joint center migration.

[0031] 2. This invention uses a constant tension cable winding component, an absolute length encoding component, and a cable tension sampling component in combination to keep the flexible measuring cable taut during movement and simultaneously obtain length and tension data. It can distinguish between effective measurement states and relaxed, stuck, or interfered states, thus improving the stability of joint motion data.

[0032] 3. This invention collects the pressure distribution changes between the fixed ring and the human body surface through the fixed ring pressure balance component, and identifies the fixed ring slippage by combining the length changes of the six flexible measuring cables, thereby reducing the impact of skin slippage and soft tissue deformation on joint motion monitoring results, making the device suitable for continuous use in rehabilitation training, home monitoring and sports training.

[0033] 4. This invention uses a central processing unit to uniformly process the absolute length of the flexible measuring cable, cable tension, proximal inertial measurement data, distal inertial measurement data, and plantar load data, so that the multi-source data form a constraint relationship around the same joint moving object. Compared with simple threshold alarms or single sensor judgment, it can provide more continuous and complete human motion monitoring results. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall device structure of the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of the reverse parallel six-wire joint monitoring unit of the present invention;

[0036] Figure 3 This is a schematic diagram of the overall front view of the present invention;

[0037] Figure 4 This is a flowchart of the data acquisition and pose solving process of the present invention.

[0038] The components include: 1. Central Processing Unit; 2. Trunk Reference Unit; 3. Pelvic Reference Unit; 4. Inverse Parallel Six-Cable Joint Monitoring Unit; 5. Foot Load Monitoring Unit; 6. Wireless Communication Unit; 7. Motion Feedback Unit; 8. Power Supply Unit; 41. Proximal Bone Segment Fixation Ring; 42. Distal Bone Segment Fixation Ring; 431. First Flexible Measuring Cable; 432. Second Flexible Measuring Cable; 433. Third Flexible Measuring Cable; 434. Fourth Flexible Measuring Cable; 435. Fifth Flexible Measuring Cable; 436. Sixth Flexible Measuring Cable; 44. Constant Tension Cable Retraction Assembly; 45. Absolute Length Encoding Assembly; 46. Cable Tension Sampling Assembly; 47. Proximal Inertial Measurement Assembly; 48. Distal Inertial Measurement Assembly; 49. Fixation Ring Pressure Balancing Assembly; 50. Edge Processor. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation Example 1:

[0041] like Figures 1 to 4 As shown, a multi-sensor fusion human motion monitoring device includes a central processing unit (1), a trunk reference unit (2), a pelvic reference unit (3), a reverse parallel six-chain joint monitoring unit (4), a plantar load monitoring unit (5), a wireless communication unit (6), a motion feedback unit (7), and a power supply unit (8). The central processing unit (1) is configured as a portable control box, which contains a main control chip, a storage chip, a clock synchronization circuit, a communication interface, and a motion analysis program. The trunk reference unit (2) is configured as an independent posture sampling module, and the pelvic reference unit (3) is configured as a lumbar and pelvic posture sampling module. Both include a three-axis acceleration sampling component, a three-axis angular velocity sampling component, a housing, a fixing strap, and a communication circuit. The plantar load monitoring unit (5) is configured as a flat load plate, with pressure sampling pads embedded in the forefoot area, the lateral metatarsal area, and the heel area of ​​the load plate. The wireless communication unit (6) uses a low-power wireless communication module, the motion feedback unit (7) uses a vibration prompt and a display prompt, and the power supply unit (8) uses a rechargeable lithium battery, a power management circuit, and a charging interface.

[0042] The reverse parallel six-cable joint monitoring unit (4) includes a proximal bone segment fixation ring (41) and a distal bone segment fixation ring (42). The proximal bone segment fixation ring (41) consists of a proximal segmented ring body, a proximal locking seat, a proximal connecting seat group, and a proximal medial pressure pad. The distal bone segment fixation ring (42) consists of a distal segmented ring body, a distal locking seat, a distal connecting seat group, and a distal medial pressure pad. Both the proximal and distal segmented ring bodies adopt an open structure, and the ring body is closed and fixed by the locking seat. The proximal connecting seat group includes six proximal cable connecting seats, and the distal connecting seat group includes six distal cable connecting seats. Each cable connecting seat includes a mounting bracket, a rotating shaft, a guide wheel, and a cable end limiting component. The groove width of the guide wheel matches the diameter of the flexible measuring cable, and the flexible measuring cable is positioned by the cable end limiting component after passing through the groove of the guide wheel.

[0043] The first flexible measuring cable (431) and the second flexible measuring cable (432) form a first cross cable pair, the third flexible measuring cable (433) and the fourth flexible measuring cable (434) form a second cross cable pair, and the fifth flexible measuring cable (435) and the sixth flexible measuring cable (436) form a third cross cable pair. The six flexible measuring cables form a spatial cross structure between the proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42). One end of each flexible measuring cable is connected to a constant tension cable winding assembly (44), and the other end is connected to a corresponding cable end limiting component. The constant tension cable winding assembly (44) includes a cable winding shell, a cable winding wheel, a cable winding shaft, a constant force spring, a damping plate, and a one-way limiting toothed ring. The absolute length encoding assembly (45) includes a multi-turn magnetic encoding disk, a magnetically sensitive reading chip, a zero-position marker, and an encoding bracket. The cable tension sampling assembly (46) includes a tension shell, a micro-force beam, a strain sampling plate, and a pre-compression guide cable post.

[0044] The proximal inertial measurement unit (47) is fixed to the proximal bone segment fixation ring (41), and the distal inertial measurement unit (48) is fixed to the distal bone segment fixation ring (42). The fixation ring pressure balancing unit (49) includes three arc-shaped skin-contact pads, three sets of pressure sampling pads, a circumferential traction belt, and a differential tensioning wheel. The three arc-shaped skin-contact pads are arranged at intervals along the inner circumference of the fixation ring, and the three sets of pressure sampling pads are located between the arc-shaped skin-contact pads and the corresponding fixation rings, respectively. The edge processor (50) is set on the central support between the two fixation rings and is connected to six sets of absolute length encoding units (45), six sets of cable tension sampling units (46), the proximal inertial measurement unit (47), the distal inertial measurement unit (48), and the fixation ring pressure balancing unit (49), respectively.

[0045] Initial calibration is performed before using the equipment. First, the operator fixes the proximal bone segment fixation ring (41) to the stable skin area corresponding to the proximal bone segment of the joint, and the distal bone segment fixation ring (42) to the stable skin area corresponding to the distal bone segment of the joint. The operator then adjusts the circumferential traction belt using the differential tension wheel to bring the pressure values ​​of the three arc-shaped skin-contact pressure pads into the set working range. Second, the edge processor (50) records the initial absolute length of the six flexible measuring cables, the initial cable tension, the initial posture of the proximal inertial measurement component (47), the initial posture of the distal inertial measurement component (48), and the initial position of the pressure center of the fixation rings. Third, the user performs a small-angle flexion and extension movement, and the central processor (1) establishes the initial correspondence between the changes in the length of the flexible measuring cables, the changes in inertial prediction, and the changes in the pressure center.

[0046] During the movement, the edge processor (50) synchronously samples the absolute length of the six flexible measuring cables, the tension of the six flexible measuring cables, the angular velocity and acceleration of the proximal inertial measurement component (47), the angular velocity and acceleration of the distal inertial measurement component (48), and the pressure data of the fixed ring pressure balancing component (49) at a frequency of 100Hz to 400Hz. The plantar load monitoring unit (5) collects the heel pressure, the first metatarsal pressure, and the fifth metatarsal pressure, and sends the support state data to the central processor (1). The central processor (1) performs cable confidence weight calculation, joint pose solution, fixed ring slip correction, and joint movement result output at a frequency of 50Hz to 200Hz.

[0047] Mathematical Models and Symbol Interpretation

[0048] In solving joint pose, the first Root flexible measuring cable in the first The theoretical length of each sampling time point is calculated using the following formula:

[0049]

[0050] In the formula, For the first Root flexible measuring cable in the first The theoretical length of each sampling time point, in mm; The flexible measuring cable is numbered, and its value is [value missing]. to Dimensionless; The sampling time is numbered and is dimensionless. For the first At each sampling time, the distal bone segment fixation ring (42) relative to the proximal bone segment fixation ring (41) Rotation matrix, dimensionless; For the first The three-dimensional coordinate vector of the distal connection point of the flexible measuring cable in the coordinate system of the distal bone segment fixation ring, in mm; For the first The three-dimensional translation vector of the distal bone segment fixation ring (42) relative to the proximal bone segment fixation ring (41) at each sampling time, in mm; For the first The three-dimensional coordinate vector of the proximal connection point of the flexible measuring cable in the coordinate system of the proximal bone segment fixation ring, in mm; This is the Euclidean norm operator, which is dimensionless.

[0051] The central processing unit (1) solves the relative pose of adjacent bone segments at each sampling time, and the objective function is as follows:

[0052]

[0053] In the formula, For the first The rotation matrix obtained by solving at each sampling time is dimensionless. For the first The translation vector obtained at each sampling time point is in mm. The operator for finding the independent variable to minimize the objective function is dimensionless. For the first Root flexible measuring cable in the first The reliable weight at each sampling time, with a value range of [value missing]. to Dimensionless; For the first Root flexible measuring cable in the first The measured length output by the absolute length encoding component (45) at each sampling time, in mm; This represents the inertial prediction constraint coefficient, in mm². The results are predicted by the near-end inertial measurement unit (47) and the far-end inertial measurement unit (48). Homogeneous pose matrix, where the rotation submatrix is ​​dimensionless and the translation column vector is in mm; for The inverse matrix of , where the rotation submatrix is ​​dimensionless and the translation column vector is in mm; For the reason and Composition Homogeneous pose matrix, where the rotation submatrix is ​​dimensionless and the translation column vector is in mm; is the logarithmic mapping operator from Lie groups to Lie algebras, and is dimensionless.

[0054] The credible weight is calculated using the following formula:

[0055]

[0056] In the formula, For the first Root flexible measuring cable in the first The reliable weight at each sampling time, with a value range of [value missing]. to Dimensionless; For the first Root flexible measuring cable in the first The complete data marker for each sampling time is set to a value of [value]. or Dimensionless; It is a natural exponential function, dimensionless; The tension deviation penalty coefficient is dimensionless. For the first Root flexible measuring cable in the first The measured tension at each sampling time, in N; For the first The calibrated working tension of the flexible measuring cable, in N; This is the consistency penalty coefficient for length variation, in mm⁻². For the first Root flexible measuring cable in the first The measured length change at each sampling time relative to the previous sampling time, in mm; The first position calculated from the inertial prediction pose The predicted length change of the root flexible measuring cable is expressed in mm.

[0057] The center of pressure of the fixed ring is calculated according to the following formula:

[0058]

[0059] In the formula, For the first The fixed ring pressure center position vector is measured at each sampling time, in mm. The pressure sampling element is numbered, and its value is [value missing]. to Dimensionless; For the first The pressure sampling pad at the first Pressure values ​​at each sampling time, in N; For the first The installation position vector of each pressure sampling element in the fixed ring coordinate system is expressed in mm.

[0060] The pose increment between adjacent sampling times is calculated using the following formula:

[0061]

[0062] In the formula, For the first The sampling time relative to the first sampling time The homogeneous pose increment at each sampling time, where the rotation submatrix is ​​dimensionless and the translation column vector is in mm; For the first The inverse matrix of the homogeneous pose matrix at each sampling time, where the rotation submatrix is ​​dimensionless and the translation column vector is in mm; For the first The homogeneous pose matrix at each sampling time, where the rotation submatrix is ​​dimensionless and the translation column vector is in mm.

[0063] The instantaneous helical motion vector of the joint is calculated according to the following formula:

[0064]

[0065] In the formula, For the first The instantaneous helical motion vector of the joint at each sampling moment is composed of linear velocity components and angular velocity components; The time interval between two adjacent sampling times is expressed in seconds. For the first The sampling time relative to the first sampling time The homogeneous pose increment at each sampling time, where the rotation submatrix is ​​dimensionless and the translation column vector is in mm; The linear velocity component in the instantaneous helical motion vector is expressed in mm / s. This represents the angular velocity component in the instantaneous helical motion vector, with units of rad / s.

[0066] The instantaneous motion axis of the joint and a point on the axis are calculated using the following formulas:

[0067]

[0068]

[0069] In the formula, For the first The unit direction vector of the instantaneous motion axis of the joint at each sampling moment, dimensionless; For the first The angular velocity components at each sampling time, in rad / s; denoted as Euclidean norm of the angular velocity component, in rad / s; For the first A point on the instantaneous motion axis of the joint at each sampling moment, in mm; This is the vector cross product operator, which is dimensionless. For the first The linear velocity component at each sampling time point, in mm / s. Specific Implementation Example 2:

[0071] like Figures 1 to 4 As shown, based on the content of the above specific embodiments, the following content is further disclosed:

[0072] In this invention, the central processing unit (1) serves as the data collection and motion result output component of the entire machine. It adopts an independent box structure, and the box contains a main control circuit board, a data storage device, a clock synchronization circuit, a power interface, and a communication interface. The main control circuit board is connected to the wireless communication unit (6), the motion feedback unit (7), and the power supply unit (8), respectively. The central processing unit (1) receives data sent by the trunk reference unit (2), the pelvic reference unit (3), the inverse parallel six-chain joint monitoring unit (4), and the foot load monitoring unit (5), and organizes the data according to a unified timestamp. The outer side of the box of the central processing unit (1) is provided with buttons, status indicator lights, and a data interface, and the back of the box is provided with a clamping seat or a strap seat for fixing to a waist strap, training frame, or rehabilitation equipment shell.

[0073] Both the trunk reference unit (2) and the pelvic reference unit (3) adopt a small posture acquisition box structure. The trunk reference unit (2) is used to fix the trunk to the back or trunk fixation belt, and the pelvic reference unit (3) is used to fix the lumbar and pelvic fixation belt. The inertial sampling circuit board, wireless communication circuit and small battery are installed inside the shell of both the trunk reference unit (2) and the pelvic reference unit (3), and the fixing belt through slots or buckles are provided on the outside of the shell. The trunk reference unit (2) and the pelvic reference unit (3) are structurally separate from the central processing unit (1). When in use, they establish a data connection with the central processing unit (1) through the wireless communication unit (6) or the short-range wired debugging interface.

[0074] The inverse parallel six-cable joint monitoring unit (4) is the core monitoring structure of this invention, which includes a proximal bone segment fixation ring (41) and a distal bone segment fixation ring (42). Both the proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42) adopt an open segmented ring structure. Each fixation ring consists of a left half ring segment, a right half ring segment, a front connecting segment, a rear connecting segment, and a locking segment. Adjacent ring segments are connected by hinges, locking screws, or snap fasteners. A dry mounting plane is provided on the outer periphery of the fixation ring. The mounting plane is used to fix the constant tension cable assembly (44), the absolute length encoding assembly (45), the proximal inertial measurement assembly (47), the distal inertial measurement assembly (48), and the edge processor (50) as supports. An arc-shaped skin-fitting pressure pad is provided on the inner side of the fixation ring. A pressure sampling pad is provided between the arc-shaped skin-fitting pressure pad and the fixation ring, so that the fixation ring can maintain a stable fit and collect pressure changes between the fixation ring and the human body surface.

[0075] The first flexible measuring cable (431), the second flexible measuring cable (432), the third flexible measuring cable (433), the fourth flexible measuring cable (434), the fifth flexible measuring cable (435), and the sixth flexible measuring cable (436) are all small-diameter flexible cables. One end of each flexible measuring cable is connected to the cable connector on the proximal bone segment fixation ring (41), and the other end is connected to the corresponding cable connector on the distal bone segment fixation ring (42). The cable connector includes a mounting ear plate, a guide wheel, a rotating shaft, and a limiting groove. The guide wheel is mounted on the mounting ear plate through the rotating shaft. The flexible measuring cable passes through the groove of the guide wheel and enters the constant tension cable take-up assembly (44). The six flexible measuring cables are not arranged in parallel, but form a cross space connection between the two fixed rings. The first flexible measuring cable (431) and the second flexible measuring cable (432) form a cross cable, the third flexible measuring cable (433) and the fourth flexible measuring cable (434) form a cross cable, and the fifth flexible measuring cable (435) and the sixth flexible measuring cable (436) form a cross cable. The three sets of cross cables are distributed at intervals along the circumference of the fixed rings.

[0076] A constant tension cable reel assembly (44) is mounted on the outer mounting plane of the proximal bone segment fixation ring (41) or the distal bone segment fixation ring (42). The constant tension cable reel assembly (44) includes a cable housing, a cable reel, a cable reel shaft, a constant force spring, a damping plate, and a limiting toothed ring. The cable reel is mounted inside the cable housing via the cable reel shaft. The flexible measuring cable is wound around the cable reel. The constant force spring is connected to the cable reel to keep the flexible measuring cable taut during joint movement. The damping plate is fitted against the side of the cable reel to limit the rapid rebound of the cable reel. The limiting toothed ring is located on the outer circumference of the cable reel to limit the rotation range of the cable reel. A cable outlet is provided on the cable housing, and a guide sleeve is provided at the cable outlet. The flexible measuring cable enters the guide reel groove through the guide sleeve.

[0077] The absolute length encoding component (45) is arranged adjacent to the constant tension take-up cable component (44). The absolute length encoding component (45) includes a multi-turn magnetic encoding disk, a magnetic reading chip, a zero-position marker, and an encoding bracket. The multi-turn magnetic encoding disk is fixed coaxially with the take-up cable shaft. When the take-up cable pulley rotates, it drives the multi-turn magnetic encoding disk to rotate synchronously. The magnetic reading chip reads the angle change of the multi-turn magnetic encoding disk and converts it into the release length of the flexible measuring cable. The zero-position marker is set at the initial take-up position of the take-up cable pulley and is used to establish the initial length reference of the flexible measuring cable during installation and debugging. The absolute length encoding component (45) is connected to the edge processor (50) through a signal line.

[0078] The cable tension sampling assembly (46) is installed on the routing channel of the flexible measuring cable. The cable tension sampling assembly (46) includes a tension housing, a micro-force beam, a strain gauge, and a preloaded guide post. The flexible measuring cable bypasses the preloaded guide post and presses against the force-bearing end of the micro-force beam. When the tension of the flexible measuring cable changes, the micro-force beam undergoes a slight deformation, which is converted into an electrical signal by the strain gauge. The tension housing is provided with a cable inlet and a cable outlet. The cable inlet, the preloaded guide post, and the cable outlet are located in the same cable routing direction, ensuring that the flexible measuring cable maintains a stable routing within the tension sampling assembly.

[0079] The proximal inertial measurement unit (47) is fixed to the outer side or top mounting of the proximal bone segment fixation ring (41), and the distal inertial measurement unit (48) is fixed to the outer side or bottom mounting of the distal bone segment fixation ring (42). Both the proximal inertial measurement unit (47) and the distal inertial measurement unit (48) include a triaxial acceleration sampler, a triaxial angular velocity sampler, a temperature sampler, and a small encapsulated housing. The proximal inertial measurement unit (47) is used to collect the motion changes of the proximal bone segment fixation ring (41), and the distal inertial measurement unit (48) is used to collect the motion changes of the distal bone segment fixation ring (42). The data collected by both units, together with the length data of the six flexible measuring cables, are fed into the central processing unit (1) for pose calculation.

[0080] The fixation ring pressure balancing assembly (49) is located inside the proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42). The fixation ring pressure balancing assembly (49) includes three arc-shaped skin-fitting pads, three sets of pressure sampling pads, a circumferential traction belt, and a differential tensioning wheel. The three arc-shaped skin-fitting pads are arranged at intervals along the inner circumference of the fixation ring, and a set of pressure sampling pads is set on the outer side of each arc-shaped skin-fitting pad. The circumferential traction belt is wrapped around the outer side of the fixation ring, and the differential tensioning wheel is connected to the circumferential traction belt. When the operator rotates the differential tensioning wheel, the circumferential traction belt generates a tightening force on the fixation ring, so that the three arc-shaped skin-fitting pads are evenly attached to the human body surface. The pressure sampling pads send the fitting pressure to the edge processor (50), and the edge processor (50) calculates the pressure center of the fixation ring based on the data of the three pressure sampling pads.

[0081] An edge processor (50) is mounted on the central support of the inverse parallel six-cable joint monitoring unit (4), which connects the proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42). The edge processor (50) includes an edge processing circuit board, a signal acquisition interface, a clock synchronization circuit, a wireless transmission circuit, and a protective housing. The edge processor (50) is connected to six sets of absolute length encoding components (45), six sets of cable tension sampling components (46), a proximal inertial measurement component (47), a distal inertial measurement component (48), and a fixation ring pressure balancing component (49), respectively. The edge processor (50) adds a unified timestamp to each sampled data to form a data frame and sends it to the central processing unit (1).

[0082] The plantar load monitoring unit (5) is an independent flat plate or insole-type load sampling structure, which includes a plantar load plate, a heel pressure sampling plate, a first metatarsal pressure sampling plate, a fifth metatarsal pressure sampling plate, and a plantar edge processing plate. The plantar load plate is made of a flexible plate or a thin rigid-flexible composite plate. The heel pressure sampling plate is set in the heel stress area, the first metatarsal pressure sampling plate is set in the medial forefoot stress area, and the fifth metatarsal pressure sampling plate is set in the lateral forefoot stress area. The plantar edge processing plate is set at one end of the plantar load plate and is electrically connected to the three pressure sampling plates. The plantar load monitoring unit (5) sends the plantar support status to the central processing unit (1) to distinguish between the support phase, the swing phase, and the center of gravity transfer process.

[0083] The wireless communication unit (6) includes a wireless communication chip, an antenna, and a communication interface. The wireless communication unit (6) is installed inside the central processing unit (1) or is set as an independent communication box. The motion feedback unit (7) includes a vibration feedback element, an audio prompt element, and a display prompt element. The motion feedback unit (7) is installed on the housing of the central processing unit (1) or is set as an independent prompt module. The power supply unit (8) includes a rechargeable battery, a power management circuit, a charging interface, and a power detection circuit. The power supply unit (8) supplies power to the central processing unit (1), the trunk reference unit (2), the pelvic reference unit (3), the inverse parallel six-chain joint monitoring unit (4), the plantar load monitoring unit (5), the wireless communication unit (6), and the motion feedback unit (7). Specific Implementation Example 3:

[0085] like Figures 1 to 4 As shown, based on the above specific embodiments, the specific application of the present invention in the knee joint rehabilitation monitoring scenario is further disclosed:

[0086] In use, the proximal bone segment fixation ring (41) is fixed in the stable area of ​​the distal thigh, and the distal bone segment fixation ring (42) is fixed in the stable area of ​​the proximal lower leg. The two fixation rings are located on the upper and lower sides of the knee joint's flexion area, respectively. The fit adjustment is completed by the arc-shaped skin-fitting pads, circumferential traction belt, and differential tension wheel in the fixation ring pressure balance assembly (49). After the adjustment is completed, the pressure sampling plates corresponding to the three arc-shaped skin-fitting pads output pressure values ​​respectively. The central processing unit (1) determines whether the fixation ring is in a stable fit state based on the three sets of pressure values ​​and records the pressure center position in this state as the initial pressure reference.

[0087] During the initial calibration phase, the user remains stationary, either standing or sitting with knees extended. The edge processor (50) simultaneously acquires the initial absolute lengths of the first flexible measuring cable (431), the second flexible measuring cable (432), the third flexible measuring cable (433), the fourth flexible measuring cable (434), the fifth flexible measuring cable (435), and the sixth flexible measuring cable (436). It also acquires the initial tension of the six flexible measuring cables, the initial posture of the proximal inertial measurement unit (47), the initial posture of the distal inertial measurement unit (48), and the initial load value of the plantar load monitoring unit (5). The central processing unit (1) establishes the aforementioned initial data as a personal wearing reference and uses the length, tension, and center of pressure of the fixed ring of the six flexible measuring cables in the initial posture as the zero-point reference for subsequent motion calculations.

[0088] During the rehabilitation training phase, the user performs knee flexion and extension, leg raising, sitting-to-standing transition, or assisted walking movements according to the set training actions. The edge processor (50) synchronously collects the absolute length data of the six flexible measuring cables, the tension data of the six flexible measuring cables, the angular velocity and acceleration data of the proximal inertial measurement component (47) and the distal inertial measurement component (48), and the pressure data of the fixed ring pressure balancing component (49) at a frequency of 100Hz to 400Hz, and encapsulates the collected results into data frames according to a unified timestamp and sends them to the central processor (1). The plantar load monitoring unit (5) synchronously collects the load changes in the heel area, the first metatarsal area, and the fifth metatarsal area to distinguish between the support state, the center of gravity transfer state, and the off-ground state.

[0089] After receiving the data frame, the central processing unit (1) first calculates the reliable weight of each flexible measuring cable based on the tension deviation and length change continuity of the six flexible measuring cables. Then, it establishes the spatial geometric constraints between the proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42) based on the measured lengths of the six flexible measuring cables. Combining the short-term motion prediction results provided by the proximal inertial measurement component (47) and the distal inertial measurement component (48), it solves the rotation and translation of the distal bone segment fixation ring (42) relative to the proximal bone segment fixation ring (41). The center of pressure of the fixation ring continuously migrates relative to the initial pressure reference. The central processing unit (1) further corrects the slippage of the fixation ring by combining the common length offset of the six flexible measuring cables, so that the output result corresponds to the actual motion state of the knee joint.

[0090] After training, the central processing unit (1) outputs the knee flexion and extension angle, axial rotation, lateral translation, joint center migration, instantaneous joint motion axis, cable status marker, fixation ring slip marker, and gait phase marker. The wireless communication unit (6) sends the above monitoring results to the rehabilitation terminal or mobile terminal, and the motion feedback unit (7) provides vibration prompts, sound prompts, or display prompts based on the output results of the central processing unit (1). Through this implementation, the present invention can complete the entire application process of device wearing, initial calibration, continuous sampling, pose solving, slip correction, motion feedback, and data recording in actual rehabilitation training. Specific Implementation Example 4:

[0092] like Figures 1 to 4 As shown, based on the content of the above specific embodiments, the working principle of the present invention is further disclosed:

[0093] The working principle of this scheme is to convert the spatial motion between adjacent bone segments of the human body, which is originally difficult to measure directly, into the changes in length, tension, pressure of the fixed rings, and inertial posture of six flexible measuring cables between two fixed rings, and then the central processing unit (1) solves the joint motion state in a unified manner. Its core is not simply to combine inertial sensors, pressure sensors and cable sensors together, but to form a wearable "inverse parallel six-cable measurement structure" through the proximal bone segment fixed ring (41), the distal bone segment fixed ring (42) and the six flexible measuring cables, so that the joint motion is constrained to the same geometric solution object.

[0094] During installation, the proximal bone segment fixation ring (41) is fixed to the corresponding area of ​​the proximal bone segment of the joint, and the distal bone segment fixation ring (42) is fixed to the corresponding area of ​​the distal bone segment of the joint. When used for knee joint monitoring, the proximal bone segment fixation ring (41) is fixed to the stable area of ​​the distal thigh, and the distal bone segment fixation ring (42) is fixed to the stable area of ​​the proximal lower leg. The two fixation rings do not directly cover the joint folding area, but are fixed to adjacent bone segments, so that the fixation rings can move synchronously with the corresponding bone segments. The arc-shaped skin-fitting pressure pad in the fixation ring pressure balance component (49) fits against the human body surface, the pressure sampling plate collects the fitting pressure, and the circumferential traction belt and differential tension wheel are used to adjust the locking degree of the fixation ring, so that the fixation ring maintains a stable circumferential support state after being worn.

[0095] During the measurement phase, the first flexible measuring cable (431), the second flexible measuring cable (432), the third flexible measuring cable (433), the fourth flexible measuring cable (434), the fifth flexible measuring cable (435), and the sixth flexible measuring cable (436) are connected between the proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42). The six flexible measuring cables are not arranged in parallel, but form three sets of spatially intersecting cable pairs. When the human joint undergoes flexion, extension, inversion, axial rotation, or lateral translation, the relative position and relative posture between the proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42) change, and the released length of the six flexible measuring cables changes accordingly. Since the six flexible measuring cables are distributed in different spatial directions, the change in the length of each cable corresponds to the relative movement in different directions between the two fixation rings. Therefore, the six cables together constitute the geometric constraints of the six degrees of freedom of the joint's relative posture.

[0096] The constant tension cable reel assembly (44) is used to maintain the flexible measuring cable in a stable tension state. During joint movement, the flexible measuring cable is released or retracted according to the changes in the distance and posture of the two fixed rings. The cable reel automatically compensates for the cable length change under the action of the constant force spring, so that the flexible measuring cable does not slack. The damping plate limits the rapid rebound of the cable reel, and the one-way limiting tooth ring limits the rotation range of the cable reel, thereby reducing cable vibration during rapid movement. The absolute length encoding assembly (45) is set coaxially with the cable reel. When the cable reel rotates, it drives the multi-turn magnetic encoding disk to rotate synchronously. The magnetic reading chip reads the angle of the encoding disk, and the edge processor (50) converts the angle change into the actual released length of the flexible measuring cable.

[0097] The cable tension sampling component (46) is used to determine the stress state of each flexible measuring cable. When the flexible measuring cable passes through the preloaded guide post, it applies force to the micro-stress beam, which undergoes a small deformation. The strain gauge converts this deformation into a tension signal. If a flexible measuring cable becomes slack, stuck, or experiences external contact or friction interference, its tension value will deviate from the calibrated working range. The central processing unit (1) will reduce the reliability of the cable data during calculation. In this way, the device does not blindly use all cable length data, but determines whether each cable is currently in an effective measurement state based on the cable tension state.

[0098] The proximal inertial measurement unit (47) and the distal inertial measurement unit (48) are fixed to the proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42), respectively, and are used to collect the angular velocity and acceleration of the two fixation rings. The role of inertial measurement data is to provide short-term, high-frequency motion trend prediction, especially to compensate for the response lag of the flexible measurement cable, winding wheel and encoding component during rapid motion. Unlike relying solely on inertial sensors, this scheme does not directly use the inertial attitude as the final joint angle, but uses the inertial data as a predictive constraint in the pose solution, and corrects the inertial drift by the absolute length of the six flexible measurement cables.

[0099] The fixed ring pressure balancing component (49) is used to identify the slippage of the fixed ring relative to the human body surface. Three arc-shaped skin-adhering pressure pads correspond to three sets of pressure sampling pads, and the central processing unit (1) calculates the pressure center of the fixed ring based on the three sets of pressure values. When the fixed ring moves stably with the bone segment, the change in the pressure center is continuous; when the fixed ring slips relative to the skin, the pressure center will shift directionally, and at the same time, the six flexible measuring cables will have a common length shift. The central processing unit (1) makes a joint judgment on the pressure center migration and the common length shift of the six cables, thereby distinguishing the fixed ring slippage from the actual joint movement and reducing the influence of skin and soft tissue displacement on the monitoring results.

[0100] The plantar load monitoring unit (5) is used to provide the boundaries of the movement phases. The heel pressure sampling plate, the first metatarsal pressure sampling plate, and the fifth metatarsal pressure sampling plate on the plantar load plate collect the force changes of the heel, the medial side of the forefoot, and the lateral side of the forefoot, respectively. The central processing unit (1) determines the support phase, swing phase, forward shift of the center of gravity, outward shift of the center of gravity, and the process of leaving the ground based on the plantar load data. The plantar load data does not replace the joint pose solution, but provides gait phase markers for the joint movement results, so that joint flexion and extension, axial rotation, lateral translation, and joint center migration can be mapped to specific movement phases.

[0101] The edge processor (50) is responsible for near-end data acquisition and preprocessing. It synchronously receives the absolute length data of the six flexible measuring cables, the tension data of the six flexible measuring cables, the near-end inertial measurement data, the far-end inertial measurement data, and the fixed ring pressure data, and adds a unified timestamp to each set of data. The edge processor (50) sends the data frames to the central processor (1), which performs time alignment on the data from different sources to avoid sampling timing deviations between cable length data, inertial data, pressure data, and plantar load data.

[0102] The pose calculation process of the central processing unit (1) is divided into four levels. The first level is the six-cable geometry solution, which calculates the spatial position and orientation of the distal bone segment fixation ring (42) relative to the proximal bone segment fixation ring (41) based on the measured lengths of the six flexible measuring cables and the spatial coordinates of the cable connection points on the two fixed rings. The second level is the cable credibility constraint, which assigns credibility weights to each flexible measuring cable based on the tension deviation, length change continuity, and inertial prediction consistency of each flexible measuring cable. The third level is the fixed ring slip correction, which corrects the slip of the fixed ring relative to the human body surface based on the pressure center migration and the common length offset of the six cables. The fourth level is the motion result output, which calculates the joint flexion and extension angles, axial rotation, lateral translation, joint center migration, and instantaneous joint motion axis based on the corrected relative pose of adjacent bone segments.

[0103] Specifically, when a person completes a knee flexion-extension movement, the thigh drives the proximal bone segment fixation ring (41) to move, and the lower leg drives the distal bone segment fixation ring (42) to move, causing a change in the relative posture between the two fixation rings. The six flexible measuring cables located on the anterior, posterior, medial, and lateral sides will produce different length changes. After the central processing unit (1) reads the length changes of the six cables, it can determine that the movement includes not only changes in flexion-extension angles, but also axial rotation of the tibia relative to the femur, varus-valgus displacement, and slight translation in the anterior-posterior direction. If the plantar load in a certain movement shows normal support phase, but abnormal migration of the instantaneous joint movement axis occurs, it indicates that the user has joint movement path deviation or compensatory movements during the support phase.

[0104] The feedback process of this scheme is as follows: The central processing unit (1) compares the calculated motion results with the individualized motion corridor. The individualized motion corridor can be established during the initial calibration process using normal flexion and extension movements, including the range of joint center migration, axial rotation, lateral translation, and instantaneous motion axis region at different flexion and extension angles. When the motion results exceed the set range, the central processing unit (1) controls the motion feedback unit (7) to provide vibration, sound, or display prompts, and sends the data to an external terminal via the wireless communication unit (6). The external terminal records the complete motion trajectory for use in rehabilitation training assessment, motion risk analysis, or home monitoring records.

[0105] Therefore, the overall working mechanism of this invention is as follows: external measurement benchmarks for adjacent bone segments are established using proximal bone segment fixation rings (41) and distal bone segment fixation rings (42); absolute geometric constraints between the two measurement benchmarks are established using six flexible measurement cables; constant tension cable winding assembly (44) ensures continuous cable tension; absolute length encoding assembly (45) obtains cable length; cable tension sampling assembly (46) determines cable state; proximal inertial measurement assembly (47) and distal inertial measurement assembly (48) provide high-frequency motion trends; fixation ring pressure balancing assembly (49) identifies fixation ring slippage; foot load monitoring unit (5) marks the motion stage; and finally, the central processing unit (1) fuses and generates joint motion monitoring results. This working process transforms human motion monitoring from single-angle estimation to solving the relative pose of adjacent bone segments based on spatial geometric constraints.

[0106] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0107] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multi-sensor fusion human motion monitoring device, comprising a central processing unit (1), a trunk reference unit (2), a pelvic reference unit (3), an inverse parallel six-cable joint monitoring unit (4), a foot load monitoring unit (5), a wireless communication unit (6), a motion feedback unit (7), and a power supply unit (8), characterized in that: The inverse parallel six-cable joint monitoring unit (4) includes a proximal bone segment fixation ring (41), a distal bone segment fixation ring (42), a first flexible measuring cable (431), a second flexible measuring cable (432), a third flexible measuring cable (433), a fourth flexible measuring cable (434), a fifth flexible measuring cable (435), a sixth flexible measuring cable (436), a constant tension cable receiving assembly (44), an absolute length encoding assembly (45), a cable tension sampling assembly (46), a proximal inertial measurement assembly (47), a distal inertial measurement assembly (48), a fixation ring pressure balancing assembly (49), and an edge processor (50). The proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42) are fixed along adjacent bone segments of the human body, and the six flexible measuring cables are connected in a proximal... A spatial cross-connection structure is formed between the end bone segment fixation ring (41) and the distal bone segment fixation ring (42). The constant tension cable assembly (44), the absolute length encoding assembly (45), and the cable tension sampling assembly (46) are respectively connected to the corresponding flexible measuring cable. The proximal inertial measurement assembly (47) is set on the proximal bone segment fixation ring (41), and the distal inertial measurement assembly (48) is set on the distal bone segment fixation ring (42). The edge processor (50) is electrically connected to the absolute length encoding assembly (45), the cable tension sampling assembly (46), the proximal inertial measurement assembly (47), the distal inertial measurement assembly (48), and the fixation ring pressure balancing assembly (49). The edge processor (50) is communicatively connected to the central processing unit (1).

2. The multi-sensor fusion human motion monitoring device according to claim 1, characterized in that: The proximal bone segment fixation ring (41) is provided with six proximal cable connectors, and the distal bone segment fixation ring (42) is provided with six distal cable connectors. The first flexible measuring cable (431) and the second flexible measuring cable (432) form a first cross cable pair, the third flexible measuring cable (433) and the fourth flexible measuring cable (434) form a second cross cable pair, and the fifth flexible measuring cable (435) and the sixth flexible measuring cable (436) form a third cross cable pair. The first cross cable pair, the second cross cable pair and the third cross cable pair are arranged at intervals along the circumference of the fixation ring.

3. The multi-sensor fusion human motion monitoring device according to claim 2, characterized in that: Both the proximal cable connector and the distal cable connector include a spherical hinge joint, a low-friction guide wheel, and a cable end limiting block. The flexible measuring cable passes through the low-friction guide wheel and the cable end limiting block in sequence, and the center line of the groove of the low-friction guide wheel coincides with the spatial direction of the corresponding flexible measuring cable.

4. The multi-sensor fusion human motion monitoring device according to claim 1, characterized in that: The constant tension cable winding assembly (44) includes a cable winding wheel, a constant force spring, a damping plate, and a one-way limiting toothed ring. The cable winding wheel is connected to the corresponding flexible measuring cable. The constant force spring is coaxially connected to the cable winding wheel. The damping plate is arranged close to the side of the cable winding wheel. The one-way limiting toothed ring is engaged with the outer peripheral tooth surface of the cable winding wheel.

5. The multi-sensor fusion human motion monitoring device according to claim 4, characterized in that: The absolute length encoding component (45) includes a multi-turn magnetic encoding disk, a magnetic reading chip, a zero-position marker, and an encoding bracket. The multi-turn magnetic encoding disk is coaxially fixed with the winding reel. The magnetic reading chip is mounted on the encoding bracket. The zero-position marker is set at the initial winding position of the winding reel.

6. The multi-sensor fusion human motion monitoring device according to claim 1, characterized in that: The cable tension sampling assembly (46) includes a micro cantilever beam, strain gauges and a pre-compression guide post. The flexible measuring cable bypasses the pre-compression guide post and presses against the force-bearing end of the micro cantilever beam. The strain gauges are fixed in the root region of the micro cantilever beam.

7. The multi-sensor fusion human motion monitoring device according to claim 1, characterized in that: The fixed ring pressure balancing assembly (49) includes three arc-shaped skin-fitting pads, three sets of pressure sampling plates, a circumferential traction belt, and a differential tensioning wheel. The three arc-shaped skin-fitting pads are arranged at intervals along the inner circumference of the proximal bone segment fixed ring (41) or the distal bone segment fixed ring (42). The three sets of pressure sampling plates are respectively set between the three arc-shaped skin-fitting pads and the corresponding fixed ring. The circumferential traction belt is wrapped around the outer circumference of the corresponding fixed ring. The differential tensioning wheel is connected to the circumferential traction belt.

8. The multi-sensor fusion human motion monitoring device according to claim 1, characterized in that: The foot load monitoring unit (5) includes a heel pressure plate, a first metatarsal pressure plate, a fifth metatarsal pressure plate, an arch inertial measurement plate, and a foot edge processing plate. The foot edge processing plate is electrically connected to the heel pressure plate, the first metatarsal pressure plate, the fifth metatarsal pressure plate, and the arch inertial measurement plate, respectively. The foot edge processing plate is communicatively connected to the central processing unit (1).

9. The multi-sensor fusion human motion monitoring device according to claim 1, characterized in that: The central processing unit (1) includes a joint pose solving module, a cable credible constraint module, a fixed ring slip correction module, an instantaneous axis calculation module, and a motion corridor comparison module. The joint pose solving module is connected to the cable credible constraint module, the fixed ring slip correction module, and the instantaneous axis calculation module, respectively. The instantaneous axis calculation module is connected to the motion corridor comparison module.

10. A human motion monitoring method for a multi-sensor fusion human motion monitoring device according to any one of claims 1-9, characterized in that, Includes the following steps: Sp1, the proximal bone segment fixation ring (41) and the distal bone segment fixation ring (42) are fixed to the stable skin area of ​​the adjacent bone segment respectively, and the pressure sampling values ​​of the three arc-shaped skin-adhering pressure pads are obtained through the fixation ring pressure balance component (49); Sp2, record the initial absolute length, initial tension, initial attitude of the near-end inertial measurement unit (47), and initial attitude of the far-end inertial measurement unit (48) of the six flexible measuring cables; Sp3, during the motion, the absolute length of the six flexible measuring cables, the tension of the six flexible measuring cables, the angular velocity and acceleration of the proximal inertial measurement unit (47), the angular velocity and acceleration of the distal inertial measurement unit (48), and the pressure data of the plantar load monitoring unit (5) are simultaneously sampled. Sp4, the edge processor (50) generates the confidence weights of the six flexible measurement cables based on the cable tension sampling value and the absolute length change value; Sp5, the central processing unit (1) solves the relative pose of adjacent bone segments based on the absolute length of the six flexible measuring cables, the reliable weight of the six flexible measuring cables, and the inertial predicted pose of the proximal inertial measurement component (47) and the distal inertial measurement component (48). Sp6, Central Processing Unit (1) corrects the slippage of the fixing ring relative to the skin based on the migration of the pressure center of the three arc-shaped skin-fitting pads and the common length offset of the six flexible measuring cables; Sp7, Central Processing Unit (1) calculates the instantaneous motion axis of the joint, the migration of the joint center, the lateral translation and the axial rotation based on the corrected relative pose of the adjacent bone segments; Sp8, the central processing unit (1) generates motion monitoring results based on the instantaneous motion axis of the joint, the migration amount of the joint center, the lateral translation amount, the axial rotation amount and the plantar load data, and transmits them to the external terminal through the wireless communication unit (6).

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